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Diffstat (limited to 'src/os_unix.c')
| -rw-r--r-- | src/os_unix.c | 8112 |
1 files changed, 8112 insertions, 0 deletions
diff --git a/src/os_unix.c b/src/os_unix.c new file mode 100644 index 0000000..722e4b2 --- /dev/null +++ b/src/os_unix.c @@ -0,0 +1,8112 @@ +/* +** 2004 May 22 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +****************************************************************************** +** +** This file contains the VFS implementation for unix-like operating systems +** include Linux, MacOSX, *BSD, QNX, VxWorks, AIX, HPUX, and others. +** +** There are actually several different VFS implementations in this file. +** The differences are in the way that file locking is done. The default +** implementation uses Posix Advisory Locks. Alternative implementations +** use flock(), dot-files, various proprietary locking schemas, or simply +** skip locking all together. +** +** This source file is organized into divisions where the logic for various +** subfunctions is contained within the appropriate division. PLEASE +** KEEP THE STRUCTURE OF THIS FILE INTACT. New code should be placed +** in the correct division and should be clearly labeled. +** +** The layout of divisions is as follows: +** +** * General-purpose declarations and utility functions. +** * Unique file ID logic used by VxWorks. +** * Various locking primitive implementations (all except proxy locking): +** + for Posix Advisory Locks +** + for no-op locks +** + for dot-file locks +** + for flock() locking +** + for named semaphore locks (VxWorks only) +** + for AFP filesystem locks (MacOSX only) +** * sqlite3_file methods not associated with locking. +** * Definitions of sqlite3_io_methods objects for all locking +** methods plus "finder" functions for each locking method. +** * sqlite3_vfs method implementations. +** * Locking primitives for the proxy uber-locking-method. (MacOSX only) +** * Definitions of sqlite3_vfs objects for all locking methods +** plus implementations of sqlite3_os_init() and sqlite3_os_end(). +*/ +#include "sqliteInt.h" +#if SQLITE_OS_UNIX /* This file is used on unix only */ + +/* +** There are various methods for file locking used for concurrency +** control: +** +** 1. POSIX locking (the default), +** 2. No locking, +** 3. Dot-file locking, +** 4. flock() locking, +** 5. AFP locking (OSX only), +** 6. Named POSIX semaphores (VXWorks only), +** 7. proxy locking. (OSX only) +** +** Styles 4, 5, and 7 are only available of SQLITE_ENABLE_LOCKING_STYLE +** is defined to 1. The SQLITE_ENABLE_LOCKING_STYLE also enables automatic +** selection of the appropriate locking style based on the filesystem +** where the database is located. +*/ +#if !defined(SQLITE_ENABLE_LOCKING_STYLE) +# if defined(__APPLE__) +# define SQLITE_ENABLE_LOCKING_STYLE 1 +# else +# define SQLITE_ENABLE_LOCKING_STYLE 0 +# endif +#endif + +/* Use pread() and pwrite() if they are available */ +#if defined(__APPLE__) +# define HAVE_PREAD 1 +# define HAVE_PWRITE 1 +#endif +#if defined(HAVE_PREAD64) && defined(HAVE_PWRITE64) +# undef USE_PREAD +# define USE_PREAD64 1 +#elif defined(HAVE_PREAD) && defined(HAVE_PWRITE) +# undef USE_PREAD64 +# define USE_PREAD 1 +#endif + +/* +** standard include files. +*/ +#include <sys/types.h> /* amalgamator: keep */ +#include <sys/stat.h> /* amalgamator: keep */ +#include <fcntl.h> +#include <sys/ioctl.h> +#include <unistd.h> /* amalgamator: keep */ +#include <time.h> +#include <sys/time.h> /* amalgamator: keep */ +#include <errno.h> +#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 +# include <sys/mman.h> +#endif + +#if SQLITE_ENABLE_LOCKING_STYLE +# include <sys/ioctl.h> +# include <sys/file.h> +# include <sys/param.h> +#endif /* SQLITE_ENABLE_LOCKING_STYLE */ + +/* +** Try to determine if gethostuuid() is available based on standard +** macros. This might sometimes compute the wrong value for some +** obscure platforms. For those cases, simply compile with one of +** the following: +** +** -DHAVE_GETHOSTUUID=0 +** -DHAVE_GETHOSTUUID=1 +** +** None if this matters except when building on Apple products with +** -DSQLITE_ENABLE_LOCKING_STYLE. +*/ +#ifndef HAVE_GETHOSTUUID +# define HAVE_GETHOSTUUID 0 +# if defined(__APPLE__) && ((__MAC_OS_X_VERSION_MIN_REQUIRED > 1050) || \ + (__IPHONE_OS_VERSION_MIN_REQUIRED > 2000)) +# if (!defined(TARGET_OS_EMBEDDED) || (TARGET_OS_EMBEDDED==0)) \ + && (!defined(TARGET_IPHONE_SIMULATOR) || (TARGET_IPHONE_SIMULATOR==0))\ + && (!defined(TARGET_OS_MACCATALYST) || (TARGET_OS_MACCATALYST==0)) +# undef HAVE_GETHOSTUUID +# define HAVE_GETHOSTUUID 1 +# else +# warning "gethostuuid() is disabled." +# endif +# endif +#endif + + +#if OS_VXWORKS +# include <sys/ioctl.h> +# include <semaphore.h> +# include <limits.h> +#endif /* OS_VXWORKS */ + +#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE +# include <sys/mount.h> +#endif + +#ifdef HAVE_UTIME +# include <utime.h> +#endif + +/* +** Allowed values of unixFile.fsFlags +*/ +#define SQLITE_FSFLAGS_IS_MSDOS 0x1 + +/* +** If we are to be thread-safe, include the pthreads header. +*/ +#if SQLITE_THREADSAFE +# include <pthread.h> +#endif + +/* +** Default permissions when creating a new file +*/ +#ifndef SQLITE_DEFAULT_FILE_PERMISSIONS +# define SQLITE_DEFAULT_FILE_PERMISSIONS 0644 +#endif + +/* +** Default permissions when creating auto proxy dir +*/ +#ifndef SQLITE_DEFAULT_PROXYDIR_PERMISSIONS +# define SQLITE_DEFAULT_PROXYDIR_PERMISSIONS 0755 +#endif + +/* +** Maximum supported path-length. +*/ +#define MAX_PATHNAME 512 + +/* +** Maximum supported symbolic links +*/ +#define SQLITE_MAX_SYMLINKS 100 + +/* Always cast the getpid() return type for compatibility with +** kernel modules in VxWorks. */ +#define osGetpid(X) (pid_t)getpid() + +/* +** Only set the lastErrno if the error code is a real error and not +** a normal expected return code of SQLITE_BUSY or SQLITE_OK +*/ +#define IS_LOCK_ERROR(x) ((x != SQLITE_OK) && (x != SQLITE_BUSY)) + +/* Forward references */ +typedef struct unixShm unixShm; /* Connection shared memory */ +typedef struct unixShmNode unixShmNode; /* Shared memory instance */ +typedef struct unixInodeInfo unixInodeInfo; /* An i-node */ +typedef struct UnixUnusedFd UnixUnusedFd; /* An unused file descriptor */ + +/* +** Sometimes, after a file handle is closed by SQLite, the file descriptor +** cannot be closed immediately. In these cases, instances of the following +** structure are used to store the file descriptor while waiting for an +** opportunity to either close or reuse it. +*/ +struct UnixUnusedFd { + int fd; /* File descriptor to close */ + int flags; /* Flags this file descriptor was opened with */ + UnixUnusedFd *pNext; /* Next unused file descriptor on same file */ +}; + +/* +** The unixFile structure is subclass of sqlite3_file specific to the unix +** VFS implementations. +*/ +typedef struct unixFile unixFile; +struct unixFile { + sqlite3_io_methods const *pMethod; /* Always the first entry */ + sqlite3_vfs *pVfs; /* The VFS that created this unixFile */ + unixInodeInfo *pInode; /* Info about locks on this inode */ + int h; /* The file descriptor */ + unsigned char eFileLock; /* The type of lock held on this fd */ + unsigned short int ctrlFlags; /* Behavioral bits. UNIXFILE_* flags */ + int lastErrno; /* The unix errno from last I/O error */ + void *lockingContext; /* Locking style specific state */ + UnixUnusedFd *pPreallocatedUnused; /* Pre-allocated UnixUnusedFd */ + const char *zPath; /* Name of the file */ + unixShm *pShm; /* Shared memory segment information */ + int szChunk; /* Configured by FCNTL_CHUNK_SIZE */ +#if SQLITE_MAX_MMAP_SIZE>0 + int nFetchOut; /* Number of outstanding xFetch refs */ + sqlite3_int64 mmapSize; /* Usable size of mapping at pMapRegion */ + sqlite3_int64 mmapSizeActual; /* Actual size of mapping at pMapRegion */ + sqlite3_int64 mmapSizeMax; /* Configured FCNTL_MMAP_SIZE value */ + void *pMapRegion; /* Memory mapped region */ +#endif + int sectorSize; /* Device sector size */ + int deviceCharacteristics; /* Precomputed device characteristics */ +#if SQLITE_ENABLE_LOCKING_STYLE + int openFlags; /* The flags specified at open() */ +#endif +#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__) + unsigned fsFlags; /* cached details from statfs() */ +#endif +#ifdef SQLITE_ENABLE_SETLK_TIMEOUT + unsigned iBusyTimeout; /* Wait this many millisec on locks */ +#endif +#if OS_VXWORKS + struct vxworksFileId *pId; /* Unique file ID */ +#endif +#ifdef SQLITE_DEBUG + /* The next group of variables are used to track whether or not the + ** transaction counter in bytes 24-27 of database files are updated + ** whenever any part of the database changes. An assertion fault will + ** occur if a file is updated without also updating the transaction + ** counter. This test is made to avoid new problems similar to the + ** one described by ticket #3584. + */ + unsigned char transCntrChng; /* True if the transaction counter changed */ + unsigned char dbUpdate; /* True if any part of database file changed */ + unsigned char inNormalWrite; /* True if in a normal write operation */ + +#endif + +#ifdef SQLITE_TEST + /* In test mode, increase the size of this structure a bit so that + ** it is larger than the struct CrashFile defined in test6.c. + */ + char aPadding[32]; +#endif +}; + +/* This variable holds the process id (pid) from when the xRandomness() +** method was called. If xOpen() is called from a different process id, +** indicating that a fork() has occurred, the PRNG will be reset. +*/ +static pid_t randomnessPid = 0; + +/* +** Allowed values for the unixFile.ctrlFlags bitmask: +*/ +#define UNIXFILE_EXCL 0x01 /* Connections from one process only */ +#define UNIXFILE_RDONLY 0x02 /* Connection is read only */ +#define UNIXFILE_PERSIST_WAL 0x04 /* Persistent WAL mode */ +#ifndef SQLITE_DISABLE_DIRSYNC +# define UNIXFILE_DIRSYNC 0x08 /* Directory sync needed */ +#else +# define UNIXFILE_DIRSYNC 0x00 +#endif +#define UNIXFILE_PSOW 0x10 /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */ +#define UNIXFILE_DELETE 0x20 /* Delete on close */ +#define UNIXFILE_URI 0x40 /* Filename might have query parameters */ +#define UNIXFILE_NOLOCK 0x80 /* Do no file locking */ + +/* +** Include code that is common to all os_*.c files +*/ +#include "os_common.h" + +/* +** Define various macros that are missing from some systems. +*/ +#ifndef O_LARGEFILE +# define O_LARGEFILE 0 +#endif +#ifdef SQLITE_DISABLE_LFS +# undef O_LARGEFILE +# define O_LARGEFILE 0 +#endif +#ifndef O_NOFOLLOW +# define O_NOFOLLOW 0 +#endif +#ifndef O_BINARY +# define O_BINARY 0 +#endif + +/* +** The threadid macro resolves to the thread-id or to 0. Used for +** testing and debugging only. +*/ +#if SQLITE_THREADSAFE +#define threadid pthread_self() +#else +#define threadid 0 +#endif + +/* +** HAVE_MREMAP defaults to true on Linux and false everywhere else. +*/ +#if !defined(HAVE_MREMAP) +# if defined(__linux__) && defined(_GNU_SOURCE) +# define HAVE_MREMAP 1 +# else +# define HAVE_MREMAP 0 +# endif +#endif + +/* +** Explicitly call the 64-bit version of lseek() on Android. Otherwise, lseek() +** is the 32-bit version, even if _FILE_OFFSET_BITS=64 is defined. +*/ +#ifdef __ANDROID__ +# define lseek lseek64 +#endif + +#ifdef __linux__ +/* +** Linux-specific IOCTL magic numbers used for controlling F2FS +*/ +#define F2FS_IOCTL_MAGIC 0xf5 +#define F2FS_IOC_START_ATOMIC_WRITE _IO(F2FS_IOCTL_MAGIC, 1) +#define F2FS_IOC_COMMIT_ATOMIC_WRITE _IO(F2FS_IOCTL_MAGIC, 2) +#define F2FS_IOC_START_VOLATILE_WRITE _IO(F2FS_IOCTL_MAGIC, 3) +#define F2FS_IOC_ABORT_VOLATILE_WRITE _IO(F2FS_IOCTL_MAGIC, 5) +#define F2FS_IOC_GET_FEATURES _IOR(F2FS_IOCTL_MAGIC, 12, u32) +#define F2FS_FEATURE_ATOMIC_WRITE 0x0004 +#endif /* __linux__ */ + + +/* +** Different Unix systems declare open() in different ways. Same use +** open(const char*,int,mode_t). Others use open(const char*,int,...). +** The difference is important when using a pointer to the function. +** +** The safest way to deal with the problem is to always use this wrapper +** which always has the same well-defined interface. +*/ +static int posixOpen(const char *zFile, int flags, int mode){ + return open(zFile, flags, mode); +} + +/* Forward reference */ +static int openDirectory(const char*, int*); +static int unixGetpagesize(void); + +/* +** Many system calls are accessed through pointer-to-functions so that +** they may be overridden at runtime to facilitate fault injection during +** testing and sandboxing. The following array holds the names and pointers +** to all overrideable system calls. +*/ +static struct unix_syscall { + const char *zName; /* Name of the system call */ + sqlite3_syscall_ptr pCurrent; /* Current value of the system call */ + sqlite3_syscall_ptr pDefault; /* Default value */ +} aSyscall[] = { + { "open", (sqlite3_syscall_ptr)posixOpen, 0 }, +#define osOpen ((int(*)(const char*,int,int))aSyscall[0].pCurrent) + + { "close", (sqlite3_syscall_ptr)close, 0 }, +#define osClose ((int(*)(int))aSyscall[1].pCurrent) + + { "access", (sqlite3_syscall_ptr)access, 0 }, +#define osAccess ((int(*)(const char*,int))aSyscall[2].pCurrent) + + { "getcwd", (sqlite3_syscall_ptr)getcwd, 0 }, +#define osGetcwd ((char*(*)(char*,size_t))aSyscall[3].pCurrent) + + { "stat", (sqlite3_syscall_ptr)stat, 0 }, +#define osStat ((int(*)(const char*,struct stat*))aSyscall[4].pCurrent) + +/* +** The DJGPP compiler environment looks mostly like Unix, but it +** lacks the fcntl() system call. So redefine fcntl() to be something +** that always succeeds. This means that locking does not occur under +** DJGPP. But it is DOS - what did you expect? +*/ +#ifdef __DJGPP__ + { "fstat", 0, 0 }, +#define osFstat(a,b,c) 0 +#else + { "fstat", (sqlite3_syscall_ptr)fstat, 0 }, +#define osFstat ((int(*)(int,struct stat*))aSyscall[5].pCurrent) +#endif + + { "ftruncate", (sqlite3_syscall_ptr)ftruncate, 0 }, +#define osFtruncate ((int(*)(int,off_t))aSyscall[6].pCurrent) + + { "fcntl", (sqlite3_syscall_ptr)fcntl, 0 }, +#define osFcntl ((int(*)(int,int,...))aSyscall[7].pCurrent) + + { "read", (sqlite3_syscall_ptr)read, 0 }, +#define osRead ((ssize_t(*)(int,void*,size_t))aSyscall[8].pCurrent) + +#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE + { "pread", (sqlite3_syscall_ptr)pread, 0 }, +#else + { "pread", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osPread ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[9].pCurrent) + +#if defined(USE_PREAD64) + { "pread64", (sqlite3_syscall_ptr)pread64, 0 }, +#else + { "pread64", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osPread64 ((ssize_t(*)(int,void*,size_t,off64_t))aSyscall[10].pCurrent) + + { "write", (sqlite3_syscall_ptr)write, 0 }, +#define osWrite ((ssize_t(*)(int,const void*,size_t))aSyscall[11].pCurrent) + +#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE + { "pwrite", (sqlite3_syscall_ptr)pwrite, 0 }, +#else + { "pwrite", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osPwrite ((ssize_t(*)(int,const void*,size_t,off_t))\ + aSyscall[12].pCurrent) + +#if defined(USE_PREAD64) + { "pwrite64", (sqlite3_syscall_ptr)pwrite64, 0 }, +#else + { "pwrite64", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osPwrite64 ((ssize_t(*)(int,const void*,size_t,off64_t))\ + aSyscall[13].pCurrent) + + { "fchmod", (sqlite3_syscall_ptr)fchmod, 0 }, +#define osFchmod ((int(*)(int,mode_t))aSyscall[14].pCurrent) + +#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE + { "fallocate", (sqlite3_syscall_ptr)posix_fallocate, 0 }, +#else + { "fallocate", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osFallocate ((int(*)(int,off_t,off_t))aSyscall[15].pCurrent) + + { "unlink", (sqlite3_syscall_ptr)unlink, 0 }, +#define osUnlink ((int(*)(const char*))aSyscall[16].pCurrent) + + { "openDirectory", (sqlite3_syscall_ptr)openDirectory, 0 }, +#define osOpenDirectory ((int(*)(const char*,int*))aSyscall[17].pCurrent) + + { "mkdir", (sqlite3_syscall_ptr)mkdir, 0 }, +#define osMkdir ((int(*)(const char*,mode_t))aSyscall[18].pCurrent) + + { "rmdir", (sqlite3_syscall_ptr)rmdir, 0 }, +#define osRmdir ((int(*)(const char*))aSyscall[19].pCurrent) + +#if defined(HAVE_FCHOWN) + { "fchown", (sqlite3_syscall_ptr)fchown, 0 }, +#else + { "fchown", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osFchown ((int(*)(int,uid_t,gid_t))aSyscall[20].pCurrent) + +#if defined(HAVE_FCHOWN) + { "geteuid", (sqlite3_syscall_ptr)geteuid, 0 }, +#else + { "geteuid", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osGeteuid ((uid_t(*)(void))aSyscall[21].pCurrent) + +#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 + { "mmap", (sqlite3_syscall_ptr)mmap, 0 }, +#else + { "mmap", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osMmap ((void*(*)(void*,size_t,int,int,int,off_t))aSyscall[22].pCurrent) + +#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 + { "munmap", (sqlite3_syscall_ptr)munmap, 0 }, +#else + { "munmap", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osMunmap ((int(*)(void*,size_t))aSyscall[23].pCurrent) + +#if HAVE_MREMAP && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0) + { "mremap", (sqlite3_syscall_ptr)mremap, 0 }, +#else + { "mremap", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osMremap ((void*(*)(void*,size_t,size_t,int,...))aSyscall[24].pCurrent) + +#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 + { "getpagesize", (sqlite3_syscall_ptr)unixGetpagesize, 0 }, +#else + { "getpagesize", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osGetpagesize ((int(*)(void))aSyscall[25].pCurrent) + +#if defined(HAVE_READLINK) + { "readlink", (sqlite3_syscall_ptr)readlink, 0 }, +#else + { "readlink", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osReadlink ((ssize_t(*)(const char*,char*,size_t))aSyscall[26].pCurrent) + +#if defined(HAVE_LSTAT) + { "lstat", (sqlite3_syscall_ptr)lstat, 0 }, +#else + { "lstat", (sqlite3_syscall_ptr)0, 0 }, +#endif +#define osLstat ((int(*)(const char*,struct stat*))aSyscall[27].pCurrent) + +#if defined(__linux__) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE) +# ifdef __ANDROID__ + { "ioctl", (sqlite3_syscall_ptr)(int(*)(int, int, ...))ioctl, 0 }, +#define osIoctl ((int(*)(int,int,...))aSyscall[28].pCurrent) +# else + { "ioctl", (sqlite3_syscall_ptr)ioctl, 0 }, +#define osIoctl ((int(*)(int,unsigned long,...))aSyscall[28].pCurrent) +# endif +#else + { "ioctl", (sqlite3_syscall_ptr)0, 0 }, +#endif + +}; /* End of the overrideable system calls */ + + +/* +** On some systems, calls to fchown() will trigger a message in a security +** log if they come from non-root processes. So avoid calling fchown() if +** we are not running as root. +*/ +static int robustFchown(int fd, uid_t uid, gid_t gid){ +#if defined(HAVE_FCHOWN) + return osGeteuid() ? 0 : osFchown(fd,uid,gid); +#else + return 0; +#endif +} + +/* +** This is the xSetSystemCall() method of sqlite3_vfs for all of the +** "unix" VFSes. Return SQLITE_OK opon successfully updating the +** system call pointer, or SQLITE_NOTFOUND if there is no configurable +** system call named zName. +*/ +static int unixSetSystemCall( + sqlite3_vfs *pNotUsed, /* The VFS pointer. Not used */ + const char *zName, /* Name of system call to override */ + sqlite3_syscall_ptr pNewFunc /* Pointer to new system call value */ +){ + unsigned int i; + int rc = SQLITE_NOTFOUND; + + UNUSED_PARAMETER(pNotUsed); + if( zName==0 ){ + /* If no zName is given, restore all system calls to their default + ** settings and return NULL + */ + rc = SQLITE_OK; + for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){ + if( aSyscall[i].pDefault ){ + aSyscall[i].pCurrent = aSyscall[i].pDefault; + } + } + }else{ + /* If zName is specified, operate on only the one system call + ** specified. + */ + for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){ + if( strcmp(zName, aSyscall[i].zName)==0 ){ + if( aSyscall[i].pDefault==0 ){ + aSyscall[i].pDefault = aSyscall[i].pCurrent; + } + rc = SQLITE_OK; + if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault; + aSyscall[i].pCurrent = pNewFunc; + break; + } + } + } + return rc; +} + +/* +** Return the value of a system call. Return NULL if zName is not a +** recognized system call name. NULL is also returned if the system call +** is currently undefined. +*/ +static sqlite3_syscall_ptr unixGetSystemCall( + sqlite3_vfs *pNotUsed, + const char *zName +){ + unsigned int i; + + UNUSED_PARAMETER(pNotUsed); + for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){ + if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent; + } + return 0; +} + +/* +** Return the name of the first system call after zName. If zName==NULL +** then return the name of the first system call. Return NULL if zName +** is the last system call or if zName is not the name of a valid +** system call. +*/ +static const char *unixNextSystemCall(sqlite3_vfs *p, const char *zName){ + int i = -1; + + UNUSED_PARAMETER(p); + if( zName ){ + for(i=0; i<ArraySize(aSyscall)-1; i++){ + if( strcmp(zName, aSyscall[i].zName)==0 ) break; + } + } + for(i++; i<ArraySize(aSyscall); i++){ + if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName; + } + return 0; +} + +/* +** Do not accept any file descriptor less than this value, in order to avoid +** opening database file using file descriptors that are commonly used for +** standard input, output, and error. +*/ +#ifndef SQLITE_MINIMUM_FILE_DESCRIPTOR +# define SQLITE_MINIMUM_FILE_DESCRIPTOR 3 +#endif + +/* +** Invoke open(). Do so multiple times, until it either succeeds or +** fails for some reason other than EINTR. +** +** If the file creation mode "m" is 0 then set it to the default for +** SQLite. The default is SQLITE_DEFAULT_FILE_PERMISSIONS (normally +** 0644) as modified by the system umask. If m is not 0, then +** make the file creation mode be exactly m ignoring the umask. +** +** The m parameter will be non-zero only when creating -wal, -journal, +** and -shm files. We want those files to have *exactly* the same +** permissions as their original database, unadulterated by the umask. +** In that way, if a database file is -rw-rw-rw or -rw-rw-r-, and a +** transaction crashes and leaves behind hot journals, then any +** process that is able to write to the database will also be able to +** recover the hot journals. +*/ +static int robust_open(const char *z, int f, mode_t m){ + int fd; + mode_t m2 = m ? m : SQLITE_DEFAULT_FILE_PERMISSIONS; + while(1){ +#if defined(O_CLOEXEC) + fd = osOpen(z,f|O_CLOEXEC,m2); +#else + fd = osOpen(z,f,m2); +#endif + if( fd<0 ){ + if( errno==EINTR ) continue; + break; + } + if( fd>=SQLITE_MINIMUM_FILE_DESCRIPTOR ) break; + if( (f & (O_EXCL|O_CREAT))==(O_EXCL|O_CREAT) ){ + (void)osUnlink(z); + } + osClose(fd); + sqlite3_log(SQLITE_WARNING, + "attempt to open \"%s\" as file descriptor %d", z, fd); + fd = -1; + if( osOpen("/dev/null", O_RDONLY, m)<0 ) break; + } + if( fd>=0 ){ + if( m!=0 ){ + struct stat statbuf; + if( osFstat(fd, &statbuf)==0 + && statbuf.st_size==0 + && (statbuf.st_mode&0777)!=m + ){ + osFchmod(fd, m); + } + } +#if defined(FD_CLOEXEC) && (!defined(O_CLOEXEC) || O_CLOEXEC==0) + osFcntl(fd, F_SETFD, osFcntl(fd, F_GETFD, 0) | FD_CLOEXEC); +#endif + } + return fd; +} + +/* +** Helper functions to obtain and relinquish the global mutex. The +** global mutex is used to protect the unixInodeInfo and +** vxworksFileId objects used by this file, all of which may be +** shared by multiple threads. +** +** Function unixMutexHeld() is used to assert() that the global mutex +** is held when required. This function is only used as part of assert() +** statements. e.g. +** +** unixEnterMutex() +** assert( unixMutexHeld() ); +** unixEnterLeave() +** +** To prevent deadlock, the global unixBigLock must must be acquired +** before the unixInodeInfo.pLockMutex mutex, if both are held. It is +** OK to get the pLockMutex without holding unixBigLock first, but if +** that happens, the unixBigLock mutex must not be acquired until after +** pLockMutex is released. +** +** OK: enter(unixBigLock), enter(pLockInfo) +** OK: enter(unixBigLock) +** OK: enter(pLockInfo) +** ERROR: enter(pLockInfo), enter(unixBigLock) +*/ +static sqlite3_mutex *unixBigLock = 0; +static void unixEnterMutex(void){ + assert( sqlite3_mutex_notheld(unixBigLock) ); /* Not a recursive mutex */ + sqlite3_mutex_enter(unixBigLock); +} +static void unixLeaveMutex(void){ + assert( sqlite3_mutex_held(unixBigLock) ); + sqlite3_mutex_leave(unixBigLock); +} +#ifdef SQLITE_DEBUG +static int unixMutexHeld(void) { + return sqlite3_mutex_held(unixBigLock); +} +#endif + + +#ifdef SQLITE_HAVE_OS_TRACE +/* +** Helper function for printing out trace information from debugging +** binaries. This returns the string representation of the supplied +** integer lock-type. +*/ +static const char *azFileLock(int eFileLock){ + switch( eFileLock ){ + case NO_LOCK: return "NONE"; + case SHARED_LOCK: return "SHARED"; + case RESERVED_LOCK: return "RESERVED"; + case PENDING_LOCK: return "PENDING"; + case EXCLUSIVE_LOCK: return "EXCLUSIVE"; + } + return "ERROR"; +} +#endif + +#ifdef SQLITE_LOCK_TRACE +/* +** Print out information about all locking operations. +** +** This routine is used for troubleshooting locks on multithreaded +** platforms. Enable by compiling with the -DSQLITE_LOCK_TRACE +** command-line option on the compiler. This code is normally +** turned off. +*/ +static int lockTrace(int fd, int op, struct flock *p){ + char *zOpName, *zType; + int s; + int savedErrno; + if( op==F_GETLK ){ + zOpName = "GETLK"; + }else if( op==F_SETLK ){ + zOpName = "SETLK"; + }else{ + s = osFcntl(fd, op, p); + sqlite3DebugPrintf("fcntl unknown %d %d %d\n", fd, op, s); + return s; + } + if( p->l_type==F_RDLCK ){ + zType = "RDLCK"; + }else if( p->l_type==F_WRLCK ){ + zType = "WRLCK"; + }else if( p->l_type==F_UNLCK ){ + zType = "UNLCK"; + }else{ + assert( 0 ); + } + assert( p->l_whence==SEEK_SET ); + s = osFcntl(fd, op, p); + savedErrno = errno; + sqlite3DebugPrintf("fcntl %d %d %s %s %d %d %d %d\n", + threadid, fd, zOpName, zType, (int)p->l_start, (int)p->l_len, + (int)p->l_pid, s); + if( s==(-1) && op==F_SETLK && (p->l_type==F_RDLCK || p->l_type==F_WRLCK) ){ + struct flock l2; + l2 = *p; + osFcntl(fd, F_GETLK, &l2); + if( l2.l_type==F_RDLCK ){ + zType = "RDLCK"; + }else if( l2.l_type==F_WRLCK ){ + zType = "WRLCK"; + }else if( l2.l_type==F_UNLCK ){ + zType = "UNLCK"; + }else{ + assert( 0 ); + } + sqlite3DebugPrintf("fcntl-failure-reason: %s %d %d %d\n", + zType, (int)l2.l_start, (int)l2.l_len, (int)l2.l_pid); + } + errno = savedErrno; + return s; +} +#undef osFcntl +#define osFcntl lockTrace +#endif /* SQLITE_LOCK_TRACE */ + +/* +** Retry ftruncate() calls that fail due to EINTR +** +** All calls to ftruncate() within this file should be made through +** this wrapper. On the Android platform, bypassing the logic below +** could lead to a corrupt database. +*/ +static int robust_ftruncate(int h, sqlite3_int64 sz){ + int rc; +#ifdef __ANDROID__ + /* On Android, ftruncate() always uses 32-bit offsets, even if + ** _FILE_OFFSET_BITS=64 is defined. This means it is unsafe to attempt to + ** truncate a file to any size larger than 2GiB. Silently ignore any + ** such attempts. */ + if( sz>(sqlite3_int64)0x7FFFFFFF ){ + rc = SQLITE_OK; + }else +#endif + do{ rc = osFtruncate(h,sz); }while( rc<0 && errno==EINTR ); + return rc; +} + +/* +** This routine translates a standard POSIX errno code into something +** useful to the clients of the sqlite3 functions. Specifically, it is +** intended to translate a variety of "try again" errors into SQLITE_BUSY +** and a variety of "please close the file descriptor NOW" errors into +** SQLITE_IOERR +** +** Errors during initialization of locks, or file system support for locks, +** should handle ENOLCK, ENOTSUP, EOPNOTSUPP separately. +*/ +static int sqliteErrorFromPosixError(int posixError, int sqliteIOErr) { + assert( (sqliteIOErr == SQLITE_IOERR_LOCK) || + (sqliteIOErr == SQLITE_IOERR_UNLOCK) || + (sqliteIOErr == SQLITE_IOERR_RDLOCK) || + (sqliteIOErr == SQLITE_IOERR_CHECKRESERVEDLOCK) ); + switch (posixError) { + case EACCES: + case EAGAIN: + case ETIMEDOUT: + case EBUSY: + case EINTR: + case ENOLCK: + /* random NFS retry error, unless during file system support + * introspection, in which it actually means what it says */ + return SQLITE_BUSY; + + case EPERM: + return SQLITE_PERM; + + default: + return sqliteIOErr; + } +} + + +/****************************************************************************** +****************** Begin Unique File ID Utility Used By VxWorks *************** +** +** On most versions of unix, we can get a unique ID for a file by concatenating +** the device number and the inode number. But this does not work on VxWorks. +** On VxWorks, a unique file id must be based on the canonical filename. +** +** A pointer to an instance of the following structure can be used as a +** unique file ID in VxWorks. Each instance of this structure contains +** a copy of the canonical filename. There is also a reference count. +** The structure is reclaimed when the number of pointers to it drops to +** zero. +** +** There are never very many files open at one time and lookups are not +** a performance-critical path, so it is sufficient to put these +** structures on a linked list. +*/ +struct vxworksFileId { + struct vxworksFileId *pNext; /* Next in a list of them all */ + int nRef; /* Number of references to this one */ + int nName; /* Length of the zCanonicalName[] string */ + char *zCanonicalName; /* Canonical filename */ +}; + +#if OS_VXWORKS +/* +** All unique filenames are held on a linked list headed by this +** variable: +*/ +static struct vxworksFileId *vxworksFileList = 0; + +/* +** Simplify a filename into its canonical form +** by making the following changes: +** +** * removing any trailing and duplicate / +** * convert /./ into just / +** * convert /A/../ where A is any simple name into just / +** +** Changes are made in-place. Return the new name length. +** +** The original filename is in z[0..n-1]. Return the number of +** characters in the simplified name. +*/ +static int vxworksSimplifyName(char *z, int n){ + int i, j; + while( n>1 && z[n-1]=='/' ){ n--; } + for(i=j=0; i<n; i++){ + if( z[i]=='/' ){ + if( z[i+1]=='/' ) continue; + if( z[i+1]=='.' && i+2<n && z[i+2]=='/' ){ + i += 1; + continue; + } + if( z[i+1]=='.' && i+3<n && z[i+2]=='.' && z[i+3]=='/' ){ + while( j>0 && z[j-1]!='/' ){ j--; } + if( j>0 ){ j--; } + i += 2; + continue; + } + } + z[j++] = z[i]; + } + z[j] = 0; + return j; +} + +/* +** Find a unique file ID for the given absolute pathname. Return +** a pointer to the vxworksFileId object. This pointer is the unique +** file ID. +** +** The nRef field of the vxworksFileId object is incremented before +** the object is returned. A new vxworksFileId object is created +** and added to the global list if necessary. +** +** If a memory allocation error occurs, return NULL. +*/ +static struct vxworksFileId *vxworksFindFileId(const char *zAbsoluteName){ + struct vxworksFileId *pNew; /* search key and new file ID */ + struct vxworksFileId *pCandidate; /* For looping over existing file IDs */ + int n; /* Length of zAbsoluteName string */ + + assert( zAbsoluteName[0]=='/' ); + n = (int)strlen(zAbsoluteName); + pNew = sqlite3_malloc64( sizeof(*pNew) + (n+1) ); + if( pNew==0 ) return 0; + pNew->zCanonicalName = (char*)&pNew[1]; + memcpy(pNew->zCanonicalName, zAbsoluteName, n+1); + n = vxworksSimplifyName(pNew->zCanonicalName, n); + + /* Search for an existing entry that matching the canonical name. + ** If found, increment the reference count and return a pointer to + ** the existing file ID. + */ + unixEnterMutex(); + for(pCandidate=vxworksFileList; pCandidate; pCandidate=pCandidate->pNext){ + if( pCandidate->nName==n + && memcmp(pCandidate->zCanonicalName, pNew->zCanonicalName, n)==0 + ){ + sqlite3_free(pNew); + pCandidate->nRef++; + unixLeaveMutex(); + return pCandidate; + } + } + + /* No match was found. We will make a new file ID */ + pNew->nRef = 1; + pNew->nName = n; + pNew->pNext = vxworksFileList; + vxworksFileList = pNew; + unixLeaveMutex(); + return pNew; +} + +/* +** Decrement the reference count on a vxworksFileId object. Free +** the object when the reference count reaches zero. +*/ +static void vxworksReleaseFileId(struct vxworksFileId *pId){ + unixEnterMutex(); + assert( pId->nRef>0 ); + pId->nRef--; + if( pId->nRef==0 ){ + struct vxworksFileId **pp; + for(pp=&vxworksFileList; *pp && *pp!=pId; pp = &((*pp)->pNext)){} + assert( *pp==pId ); + *pp = pId->pNext; + sqlite3_free(pId); + } + unixLeaveMutex(); +} +#endif /* OS_VXWORKS */ +/*************** End of Unique File ID Utility Used By VxWorks **************** +******************************************************************************/ + + +/****************************************************************************** +*************************** Posix Advisory Locking **************************** +** +** POSIX advisory locks are broken by design. ANSI STD 1003.1 (1996) +** section 6.5.2.2 lines 483 through 490 specify that when a process +** sets or clears a lock, that operation overrides any prior locks set +** by the same process. It does not explicitly say so, but this implies +** that it overrides locks set by the same process using a different +** file descriptor. Consider this test case: +** +** int fd1 = open("./file1", O_RDWR|O_CREAT, 0644); +** int fd2 = open("./file2", O_RDWR|O_CREAT, 0644); +** +** Suppose ./file1 and ./file2 are really the same file (because +** one is a hard or symbolic link to the other) then if you set +** an exclusive lock on fd1, then try to get an exclusive lock +** on fd2, it works. I would have expected the second lock to +** fail since there was already a lock on the file due to fd1. +** But not so. Since both locks came from the same process, the +** second overrides the first, even though they were on different +** file descriptors opened on different file names. +** +** This means that we cannot use POSIX locks to synchronize file access +** among competing threads of the same process. POSIX locks will work fine +** to synchronize access for threads in separate processes, but not +** threads within the same process. +** +** To work around the problem, SQLite has to manage file locks internally +** on its own. Whenever a new database is opened, we have to find the +** specific inode of the database file (the inode is determined by the +** st_dev and st_ino fields of the stat structure that fstat() fills in) +** and check for locks already existing on that inode. When locks are +** created or removed, we have to look at our own internal record of the +** locks to see if another thread has previously set a lock on that same +** inode. +** +** (Aside: The use of inode numbers as unique IDs does not work on VxWorks. +** For VxWorks, we have to use the alternative unique ID system based on +** canonical filename and implemented in the previous division.) +** +** The sqlite3_file structure for POSIX is no longer just an integer file +** descriptor. It is now a structure that holds the integer file +** descriptor and a pointer to a structure that describes the internal +** locks on the corresponding inode. There is one locking structure +** per inode, so if the same inode is opened twice, both unixFile structures +** point to the same locking structure. The locking structure keeps +** a reference count (so we will know when to delete it) and a "cnt" +** field that tells us its internal lock status. cnt==0 means the +** file is unlocked. cnt==-1 means the file has an exclusive lock. +** cnt>0 means there are cnt shared locks on the file. +** +** Any attempt to lock or unlock a file first checks the locking +** structure. The fcntl() system call is only invoked to set a +** POSIX lock if the internal lock structure transitions between +** a locked and an unlocked state. +** +** But wait: there are yet more problems with POSIX advisory locks. +** +** If you close a file descriptor that points to a file that has locks, +** all locks on that file that are owned by the current process are +** released. To work around this problem, each unixInodeInfo object +** maintains a count of the number of pending locks on tha inode. +** When an attempt is made to close an unixFile, if there are +** other unixFile open on the same inode that are holding locks, the call +** to close() the file descriptor is deferred until all of the locks clear. +** The unixInodeInfo structure keeps a list of file descriptors that need to +** be closed and that list is walked (and cleared) when the last lock +** clears. +** +** Yet another problem: LinuxThreads do not play well with posix locks. +** +** Many older versions of linux use the LinuxThreads library which is +** not posix compliant. Under LinuxThreads, a lock created by thread +** A cannot be modified or overridden by a different thread B. +** Only thread A can modify the lock. Locking behavior is correct +** if the appliation uses the newer Native Posix Thread Library (NPTL) +** on linux - with NPTL a lock created by thread A can override locks +** in thread B. But there is no way to know at compile-time which +** threading library is being used. So there is no way to know at +** compile-time whether or not thread A can override locks on thread B. +** One has to do a run-time check to discover the behavior of the +** current process. +** +** SQLite used to support LinuxThreads. But support for LinuxThreads +** was dropped beginning with version 3.7.0. SQLite will still work with +** LinuxThreads provided that (1) there is no more than one connection +** per database file in the same process and (2) database connections +** do not move across threads. +*/ + +/* +** An instance of the following structure serves as the key used +** to locate a particular unixInodeInfo object. +*/ +struct unixFileId { + dev_t dev; /* Device number */ +#if OS_VXWORKS + struct vxworksFileId *pId; /* Unique file ID for vxworks. */ +#else + /* We are told that some versions of Android contain a bug that + ** sizes ino_t at only 32-bits instead of 64-bits. (See + ** https://android-review.googlesource.com/#/c/115351/3/dist/sqlite3.c) + ** To work around this, always allocate 64-bits for the inode number. + ** On small machines that only have 32-bit inodes, this wastes 4 bytes, + ** but that should not be a big deal. */ + /* WAS: ino_t ino; */ + u64 ino; /* Inode number */ +#endif +}; + +/* +** An instance of the following structure is allocated for each open +** inode. +** +** A single inode can have multiple file descriptors, so each unixFile +** structure contains a pointer to an instance of this object and this +** object keeps a count of the number of unixFile pointing to it. +** +** Mutex rules: +** +** (1) Only the pLockMutex mutex must be held in order to read or write +** any of the locking fields: +** nShared, nLock, eFileLock, bProcessLock, pUnused +** +** (2) When nRef>0, then the following fields are unchanging and can +** be read (but not written) without holding any mutex: +** fileId, pLockMutex +** +** (3) With the exceptions above, all the fields may only be read +** or written while holding the global unixBigLock mutex. +** +** Deadlock prevention: The global unixBigLock mutex may not +** be acquired while holding the pLockMutex mutex. If both unixBigLock +** and pLockMutex are needed, then unixBigLock must be acquired first. +*/ +struct unixInodeInfo { + struct unixFileId fileId; /* The lookup key */ + sqlite3_mutex *pLockMutex; /* Hold this mutex for... */ + int nShared; /* Number of SHARED locks held */ + int nLock; /* Number of outstanding file locks */ + unsigned char eFileLock; /* One of SHARED_LOCK, RESERVED_LOCK etc. */ + unsigned char bProcessLock; /* An exclusive process lock is held */ + UnixUnusedFd *pUnused; /* Unused file descriptors to close */ + int nRef; /* Number of pointers to this structure */ + unixShmNode *pShmNode; /* Shared memory associated with this inode */ + unixInodeInfo *pNext; /* List of all unixInodeInfo objects */ + unixInodeInfo *pPrev; /* .... doubly linked */ +#if SQLITE_ENABLE_LOCKING_STYLE + unsigned long long sharedByte; /* for AFP simulated shared lock */ +#endif +#if OS_VXWORKS + sem_t *pSem; /* Named POSIX semaphore */ + char aSemName[MAX_PATHNAME+2]; /* Name of that semaphore */ +#endif +}; + +/* +** A lists of all unixInodeInfo objects. +** +** Must hold unixBigLock in order to read or write this variable. +*/ +static unixInodeInfo *inodeList = 0; /* All unixInodeInfo objects */ + +#ifdef SQLITE_DEBUG +/* +** True if the inode mutex (on the unixFile.pFileMutex field) is held, or not. +** This routine is used only within assert() to help verify correct mutex +** usage. +*/ +int unixFileMutexHeld(unixFile *pFile){ + assert( pFile->pInode ); + return sqlite3_mutex_held(pFile->pInode->pLockMutex); +} +int unixFileMutexNotheld(unixFile *pFile){ + assert( pFile->pInode ); + return sqlite3_mutex_notheld(pFile->pInode->pLockMutex); +} +#endif + +/* +** +** This function - unixLogErrorAtLine(), is only ever called via the macro +** unixLogError(). +** +** It is invoked after an error occurs in an OS function and errno has been +** set. It logs a message using sqlite3_log() containing the current value of +** errno and, if possible, the human-readable equivalent from strerror() or +** strerror_r(). +** +** The first argument passed to the macro should be the error code that +** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN). +** The two subsequent arguments should be the name of the OS function that +** failed (e.g. "unlink", "open") and the associated file-system path, +** if any. +*/ +#define unixLogError(a,b,c) unixLogErrorAtLine(a,b,c,__LINE__) +static int unixLogErrorAtLine( + int errcode, /* SQLite error code */ + const char *zFunc, /* Name of OS function that failed */ + const char *zPath, /* File path associated with error */ + int iLine /* Source line number where error occurred */ +){ + char *zErr; /* Message from strerror() or equivalent */ + int iErrno = errno; /* Saved syscall error number */ + + /* If this is not a threadsafe build (SQLITE_THREADSAFE==0), then use + ** the strerror() function to obtain the human-readable error message + ** equivalent to errno. Otherwise, use strerror_r(). + */ +#if SQLITE_THREADSAFE && defined(HAVE_STRERROR_R) + char aErr[80]; + memset(aErr, 0, sizeof(aErr)); + zErr = aErr; + + /* If STRERROR_R_CHAR_P (set by autoconf scripts) or __USE_GNU is defined, + ** assume that the system provides the GNU version of strerror_r() that + ** returns a pointer to a buffer containing the error message. That pointer + ** may point to aErr[], or it may point to some static storage somewhere. + ** Otherwise, assume that the system provides the POSIX version of + ** strerror_r(), which always writes an error message into aErr[]. + ** + ** If the code incorrectly assumes that it is the POSIX version that is + ** available, the error message will often be an empty string. Not a + ** huge problem. Incorrectly concluding that the GNU version is available + ** could lead to a segfault though. + */ +#if defined(STRERROR_R_CHAR_P) || defined(__USE_GNU) + zErr = +# endif + strerror_r(iErrno, aErr, sizeof(aErr)-1); + +#elif SQLITE_THREADSAFE + /* This is a threadsafe build, but strerror_r() is not available. */ + zErr = ""; +#else + /* Non-threadsafe build, use strerror(). */ + zErr = strerror(iErrno); +#endif + + if( zPath==0 ) zPath = ""; + sqlite3_log(errcode, + "os_unix.c:%d: (%d) %s(%s) - %s", + iLine, iErrno, zFunc, zPath, zErr + ); + + return errcode; +} + +/* +** Close a file descriptor. +** +** We assume that close() almost always works, since it is only in a +** very sick application or on a very sick platform that it might fail. +** If it does fail, simply leak the file descriptor, but do log the +** error. +** +** Note that it is not safe to retry close() after EINTR since the +** file descriptor might have already been reused by another thread. +** So we don't even try to recover from an EINTR. Just log the error +** and move on. +*/ +static void robust_close(unixFile *pFile, int h, int lineno){ + if( osClose(h) ){ + unixLogErrorAtLine(SQLITE_IOERR_CLOSE, "close", + pFile ? pFile->zPath : 0, lineno); + } +} + +/* +** Set the pFile->lastErrno. Do this in a subroutine as that provides +** a convenient place to set a breakpoint. +*/ +static void storeLastErrno(unixFile *pFile, int error){ + pFile->lastErrno = error; +} + +/* +** Close all file descriptors accumuated in the unixInodeInfo->pUnused list. +*/ +static void closePendingFds(unixFile *pFile){ + unixInodeInfo *pInode = pFile->pInode; + UnixUnusedFd *p; + UnixUnusedFd *pNext; + assert( unixFileMutexHeld(pFile) ); + for(p=pInode->pUnused; p; p=pNext){ + pNext = p->pNext; + robust_close(pFile, p->fd, __LINE__); + sqlite3_free(p); + } + pInode->pUnused = 0; +} + +/* +** Release a unixInodeInfo structure previously allocated by findInodeInfo(). +** +** The global mutex must be held when this routine is called, but the mutex +** on the inode being deleted must NOT be held. +*/ +static void releaseInodeInfo(unixFile *pFile){ + unixInodeInfo *pInode = pFile->pInode; + assert( unixMutexHeld() ); + assert( unixFileMutexNotheld(pFile) ); + if( ALWAYS(pInode) ){ + pInode->nRef--; + if( pInode->nRef==0 ){ + assert( pInode->pShmNode==0 ); + sqlite3_mutex_enter(pInode->pLockMutex); + closePendingFds(pFile); + sqlite3_mutex_leave(pInode->pLockMutex); + if( pInode->pPrev ){ + assert( pInode->pPrev->pNext==pInode ); + pInode->pPrev->pNext = pInode->pNext; + }else{ + assert( inodeList==pInode ); + inodeList = pInode->pNext; + } + if( pInode->pNext ){ + assert( pInode->pNext->pPrev==pInode ); + pInode->pNext->pPrev = pInode->pPrev; + } + sqlite3_mutex_free(pInode->pLockMutex); + sqlite3_free(pInode); + } + } +} + +/* +** Given a file descriptor, locate the unixInodeInfo object that +** describes that file descriptor. Create a new one if necessary. The +** return value might be uninitialized if an error occurs. +** +** The global mutex must held when calling this routine. +** +** Return an appropriate error code. +*/ +static int findInodeInfo( + unixFile *pFile, /* Unix file with file desc used in the key */ + unixInodeInfo **ppInode /* Return the unixInodeInfo object here */ +){ + int rc; /* System call return code */ + int fd; /* The file descriptor for pFile */ + struct unixFileId fileId; /* Lookup key for the unixInodeInfo */ + struct stat statbuf; /* Low-level file information */ + unixInodeInfo *pInode = 0; /* Candidate unixInodeInfo object */ + + assert( unixMutexHeld() ); + + /* Get low-level information about the file that we can used to + ** create a unique name for the file. + */ + fd = pFile->h; + rc = osFstat(fd, &statbuf); + if( rc!=0 ){ + storeLastErrno(pFile, errno); +#if defined(EOVERFLOW) && defined(SQLITE_DISABLE_LFS) + if( pFile->lastErrno==EOVERFLOW ) return SQLITE_NOLFS; +#endif + return SQLITE_IOERR; + } + +#ifdef __APPLE__ + /* On OS X on an msdos filesystem, the inode number is reported + ** incorrectly for zero-size files. See ticket #3260. To work + ** around this problem (we consider it a bug in OS X, not SQLite) + ** we always increase the file size to 1 by writing a single byte + ** prior to accessing the inode number. The one byte written is + ** an ASCII 'S' character which also happens to be the first byte + ** in the header of every SQLite database. In this way, if there + ** is a race condition such that another thread has already populated + ** the first page of the database, no damage is done. + */ + if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){ + do{ rc = osWrite(fd, "S", 1); }while( rc<0 && errno==EINTR ); + if( rc!=1 ){ + storeLastErrno(pFile, errno); + return SQLITE_IOERR; + } + rc = osFstat(fd, &statbuf); + if( rc!=0 ){ + storeLastErrno(pFile, errno); + return SQLITE_IOERR; + } + } +#endif + + memset(&fileId, 0, sizeof(fileId)); + fileId.dev = statbuf.st_dev; +#if OS_VXWORKS + fileId.pId = pFile->pId; +#else + fileId.ino = (u64)statbuf.st_ino; +#endif + assert( unixMutexHeld() ); + pInode = inodeList; + while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){ + pInode = pInode->pNext; + } + if( pInode==0 ){ + pInode = sqlite3_malloc64( sizeof(*pInode) ); + if( pInode==0 ){ + return SQLITE_NOMEM_BKPT; + } + memset(pInode, 0, sizeof(*pInode)); + memcpy(&pInode->fileId, &fileId, sizeof(fileId)); + if( sqlite3GlobalConfig.bCoreMutex ){ + pInode->pLockMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST); + if( pInode->pLockMutex==0 ){ + sqlite3_free(pInode); + return SQLITE_NOMEM_BKPT; + } + } + pInode->nRef = 1; + assert( unixMutexHeld() ); + pInode->pNext = inodeList; + pInode->pPrev = 0; + if( inodeList ) inodeList->pPrev = pInode; + inodeList = pInode; + }else{ + pInode->nRef++; + } + *ppInode = pInode; + return SQLITE_OK; +} + +/* +** Return TRUE if pFile has been renamed or unlinked since it was first opened. +*/ +static int fileHasMoved(unixFile *pFile){ +#if OS_VXWORKS + return pFile->pInode!=0 && pFile->pId!=pFile->pInode->fileId.pId; +#else + struct stat buf; + return pFile->pInode!=0 && + (osStat(pFile->zPath, &buf)!=0 + || (u64)buf.st_ino!=pFile->pInode->fileId.ino); +#endif +} + + +/* +** Check a unixFile that is a database. Verify the following: +** +** (1) There is exactly one hard link on the file +** (2) The file is not a symbolic link +** (3) The file has not been renamed or unlinked +** +** Issue sqlite3_log(SQLITE_WARNING,...) messages if anything is not right. +*/ +static void verifyDbFile(unixFile *pFile){ + struct stat buf; + int rc; + + /* These verifications occurs for the main database only */ + if( pFile->ctrlFlags & UNIXFILE_NOLOCK ) return; + + rc = osFstat(pFile->h, &buf); + if( rc!=0 ){ + sqlite3_log(SQLITE_WARNING, "cannot fstat db file %s", pFile->zPath); + return; + } + if( buf.st_nlink==0 ){ + sqlite3_log(SQLITE_WARNING, "file unlinked while open: %s", pFile->zPath); + return; + } + if( buf.st_nlink>1 ){ + sqlite3_log(SQLITE_WARNING, "multiple links to file: %s", pFile->zPath); + return; + } + if( fileHasMoved(pFile) ){ + sqlite3_log(SQLITE_WARNING, "file renamed while open: %s", pFile->zPath); + return; + } +} + + +/* +** This routine checks if there is a RESERVED lock held on the specified +** file by this or any other process. If such a lock is held, set *pResOut +** to a non-zero value otherwise *pResOut is set to zero. The return value +** is set to SQLITE_OK unless an I/O error occurs during lock checking. +*/ +static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){ + int rc = SQLITE_OK; + int reserved = 0; + unixFile *pFile = (unixFile*)id; + + SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); + + assert( pFile ); + assert( pFile->eFileLock<=SHARED_LOCK ); + sqlite3_mutex_enter(pFile->pInode->pLockMutex); + + /* Check if a thread in this process holds such a lock */ + if( pFile->pInode->eFileLock>SHARED_LOCK ){ + reserved = 1; + } + + /* Otherwise see if some other process holds it. + */ +#ifndef __DJGPP__ + if( !reserved && !pFile->pInode->bProcessLock ){ + struct flock lock; + lock.l_whence = SEEK_SET; + lock.l_start = RESERVED_BYTE; + lock.l_len = 1; + lock.l_type = F_WRLCK; + if( osFcntl(pFile->h, F_GETLK, &lock) ){ + rc = SQLITE_IOERR_CHECKRESERVEDLOCK; + storeLastErrno(pFile, errno); + } else if( lock.l_type!=F_UNLCK ){ + reserved = 1; + } + } +#endif + + sqlite3_mutex_leave(pFile->pInode->pLockMutex); + OSTRACE(("TEST WR-LOCK %d %d %d (unix)\n", pFile->h, rc, reserved)); + + *pResOut = reserved; + return rc; +} + +/* Forward declaration*/ +static int unixSleep(sqlite3_vfs*,int); + +/* +** Set a posix-advisory-lock. +** +** There are two versions of this routine. If compiled with +** SQLITE_ENABLE_SETLK_TIMEOUT then the routine has an extra parameter +** which is a pointer to a unixFile. If the unixFile->iBusyTimeout +** value is set, then it is the number of milliseconds to wait before +** failing the lock. The iBusyTimeout value is always reset back to +** zero on each call. +** +** If SQLITE_ENABLE_SETLK_TIMEOUT is not defined, then do a non-blocking +** attempt to set the lock. +*/ +#ifndef SQLITE_ENABLE_SETLK_TIMEOUT +# define osSetPosixAdvisoryLock(h,x,t) osFcntl(h,F_SETLK,x) +#else +static int osSetPosixAdvisoryLock( + int h, /* The file descriptor on which to take the lock */ + struct flock *pLock, /* The description of the lock */ + unixFile *pFile /* Structure holding timeout value */ +){ + int tm = pFile->iBusyTimeout; + int rc = osFcntl(h,F_SETLK,pLock); + while( rc<0 && tm>0 ){ + /* On systems that support some kind of blocking file lock with a timeout, + ** make appropriate changes here to invoke that blocking file lock. On + ** generic posix, however, there is no such API. So we simply try the + ** lock once every millisecond until either the timeout expires, or until + ** the lock is obtained. */ + unixSleep(0,1000); + rc = osFcntl(h,F_SETLK,pLock); + tm--; + } + return rc; +} +#endif /* SQLITE_ENABLE_SETLK_TIMEOUT */ + + +/* +** Attempt to set a system-lock on the file pFile. The lock is +** described by pLock. +** +** If the pFile was opened read/write from unix-excl, then the only lock +** ever obtained is an exclusive lock, and it is obtained exactly once +** the first time any lock is attempted. All subsequent system locking +** operations become no-ops. Locking operations still happen internally, +** in order to coordinate access between separate database connections +** within this process, but all of that is handled in memory and the +** operating system does not participate. +** +** This function is a pass-through to fcntl(F_SETLK) if pFile is using +** any VFS other than "unix-excl" or if pFile is opened on "unix-excl" +** and is read-only. +** +** Zero is returned if the call completes successfully, or -1 if a call +** to fcntl() fails. In this case, errno is set appropriately (by fcntl()). +*/ +static int unixFileLock(unixFile *pFile, struct flock *pLock){ + int rc; + unixInodeInfo *pInode = pFile->pInode; + assert( pInode!=0 ); + assert( sqlite3_mutex_held(pInode->pLockMutex) ); + if( (pFile->ctrlFlags & (UNIXFILE_EXCL|UNIXFILE_RDONLY))==UNIXFILE_EXCL ){ + if( pInode->bProcessLock==0 ){ + struct flock lock; + assert( pInode->nLock==0 ); + lock.l_whence = SEEK_SET; + lock.l_start = SHARED_FIRST; + lock.l_len = SHARED_SIZE; + lock.l_type = F_WRLCK; + rc = osSetPosixAdvisoryLock(pFile->h, &lock, pFile); + if( rc<0 ) return rc; + pInode->bProcessLock = 1; + pInode->nLock++; + }else{ + rc = 0; + } + }else{ + rc = osSetPosixAdvisoryLock(pFile->h, pLock, pFile); + } + return rc; +} + +/* +** Lock the file with the lock specified by parameter eFileLock - one +** of the following: +** +** (1) SHARED_LOCK +** (2) RESERVED_LOCK +** (3) PENDING_LOCK +** (4) EXCLUSIVE_LOCK +** +** Sometimes when requesting one lock state, additional lock states +** are inserted in between. The locking might fail on one of the later +** transitions leaving the lock state different from what it started but +** still short of its goal. The following chart shows the allowed +** transitions and the inserted intermediate states: +** +** UNLOCKED -> SHARED +** SHARED -> RESERVED +** SHARED -> (PENDING) -> EXCLUSIVE +** RESERVED -> (PENDING) -> EXCLUSIVE +** PENDING -> EXCLUSIVE +** +** This routine will only increase a lock. Use the sqlite3OsUnlock() +** routine to lower a locking level. +*/ +static int unixLock(sqlite3_file *id, int eFileLock){ + /* The following describes the implementation of the various locks and + ** lock transitions in terms of the POSIX advisory shared and exclusive + ** lock primitives (called read-locks and write-locks below, to avoid + ** confusion with SQLite lock names). The algorithms are complicated + ** slightly in order to be compatible with Windows95 systems simultaneously + ** accessing the same database file, in case that is ever required. + ** + ** Symbols defined in os.h indentify the 'pending byte' and the 'reserved + ** byte', each single bytes at well known offsets, and the 'shared byte + ** range', a range of 510 bytes at a well known offset. + ** + ** To obtain a SHARED lock, a read-lock is obtained on the 'pending + ** byte'. If this is successful, 'shared byte range' is read-locked + ** and the lock on the 'pending byte' released. (Legacy note: When + ** SQLite was first developed, Windows95 systems were still very common, + ** and Widnows95 lacks a shared-lock capability. So on Windows95, a + ** single randomly selected by from the 'shared byte range' is locked. + ** Windows95 is now pretty much extinct, but this work-around for the + ** lack of shared-locks on Windows95 lives on, for backwards + ** compatibility.) + ** + ** A process may only obtain a RESERVED lock after it has a SHARED lock. + ** A RESERVED lock is implemented by grabbing a write-lock on the + ** 'reserved byte'. + ** + ** A process may only obtain a PENDING lock after it has obtained a + ** SHARED lock. A PENDING lock is implemented by obtaining a write-lock + ** on the 'pending byte'. This ensures that no new SHARED locks can be + ** obtained, but existing SHARED locks are allowed to persist. A process + ** does not have to obtain a RESERVED lock on the way to a PENDING lock. + ** This property is used by the algorithm for rolling back a journal file + ** after a crash. + ** + ** An EXCLUSIVE lock, obtained after a PENDING lock is held, is + ** implemented by obtaining a write-lock on the entire 'shared byte + ** range'. Since all other locks require a read-lock on one of the bytes + ** within this range, this ensures that no other locks are held on the + ** database. + */ + int rc = SQLITE_OK; + unixFile *pFile = (unixFile*)id; + unixInodeInfo *pInode; + struct flock lock; + int tErrno = 0; + + assert( pFile ); + OSTRACE(("LOCK %d %s was %s(%s,%d) pid=%d (unix)\n", pFile->h, + azFileLock(eFileLock), azFileLock(pFile->eFileLock), + azFileLock(pFile->pInode->eFileLock), pFile->pInode->nShared, + osGetpid(0))); + + /* If there is already a lock of this type or more restrictive on the + ** unixFile, do nothing. Don't use the end_lock: exit path, as + ** unixEnterMutex() hasn't been called yet. + */ + if( pFile->eFileLock>=eFileLock ){ + OSTRACE(("LOCK %d %s ok (already held) (unix)\n", pFile->h, + azFileLock(eFileLock))); + return SQLITE_OK; + } + + /* Make sure the locking sequence is correct. + ** (1) We never move from unlocked to anything higher than shared lock. + ** (2) SQLite never explicitly requests a pendig lock. + ** (3) A shared lock is always held when a reserve lock is requested. + */ + assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK ); + assert( eFileLock!=PENDING_LOCK ); + assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK ); + + /* This mutex is needed because pFile->pInode is shared across threads + */ + pInode = pFile->pInode; + sqlite3_mutex_enter(pInode->pLockMutex); + + /* If some thread using this PID has a lock via a different unixFile* + ** handle that precludes the requested lock, return BUSY. + */ + if( (pFile->eFileLock!=pInode->eFileLock && + (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK)) + ){ + rc = SQLITE_BUSY; + goto end_lock; + } + + /* If a SHARED lock is requested, and some thread using this PID already + ** has a SHARED or RESERVED lock, then increment reference counts and + ** return SQLITE_OK. + */ + if( eFileLock==SHARED_LOCK && + (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){ + assert( eFileLock==SHARED_LOCK ); + assert( pFile->eFileLock==0 ); + assert( pInode->nShared>0 ); + pFile->eFileLock = SHARED_LOCK; + pInode->nShared++; + pInode->nLock++; + goto end_lock; + } + + + /* A PENDING lock is needed before acquiring a SHARED lock and before + ** acquiring an EXCLUSIVE lock. For the SHARED lock, the PENDING will + ** be released. + */ + lock.l_len = 1L; + lock.l_whence = SEEK_SET; + if( eFileLock==SHARED_LOCK + || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK) + ){ + lock.l_type = (eFileLock==SHARED_LOCK?F_RDLCK:F_WRLCK); + lock.l_start = PENDING_BYTE; + if( unixFileLock(pFile, &lock) ){ + tErrno = errno; + rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); + if( rc!=SQLITE_BUSY ){ + storeLastErrno(pFile, tErrno); + } + goto end_lock; + } + } + + + /* If control gets to this point, then actually go ahead and make + ** operating system calls for the specified lock. + */ + if( eFileLock==SHARED_LOCK ){ + assert( pInode->nShared==0 ); + assert( pInode->eFileLock==0 ); + assert( rc==SQLITE_OK ); + + /* Now get the read-lock */ + lock.l_start = SHARED_FIRST; + lock.l_len = SHARED_SIZE; + if( unixFileLock(pFile, &lock) ){ + tErrno = errno; + rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); + } + + /* Drop the temporary PENDING lock */ + lock.l_start = PENDING_BYTE; + lock.l_len = 1L; + lock.l_type = F_UNLCK; + if( unixFileLock(pFile, &lock) && rc==SQLITE_OK ){ + /* This could happen with a network mount */ + tErrno = errno; + rc = SQLITE_IOERR_UNLOCK; + } + + if( rc ){ + if( rc!=SQLITE_BUSY ){ + storeLastErrno(pFile, tErrno); + } + goto end_lock; + }else{ + pFile->eFileLock = SHARED_LOCK; + pInode->nLock++; + pInode->nShared = 1; + } + }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){ + /* We are trying for an exclusive lock but another thread in this + ** same process is still holding a shared lock. */ + rc = SQLITE_BUSY; + }else{ + /* The request was for a RESERVED or EXCLUSIVE lock. It is + ** assumed that there is a SHARED or greater lock on the file + ** already. + */ + assert( 0!=pFile->eFileLock ); + lock.l_type = F_WRLCK; + + assert( eFileLock==RESERVED_LOCK || eFileLock==EXCLUSIVE_LOCK ); + if( eFileLock==RESERVED_LOCK ){ + lock.l_start = RESERVED_BYTE; + lock.l_len = 1L; + }else{ + lock.l_start = SHARED_FIRST; + lock.l_len = SHARED_SIZE; + } + + if( unixFileLock(pFile, &lock) ){ + tErrno = errno; + rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); + if( rc!=SQLITE_BUSY ){ + storeLastErrno(pFile, tErrno); + } + } + } + + +#ifdef SQLITE_DEBUG + /* Set up the transaction-counter change checking flags when + ** transitioning from a SHARED to a RESERVED lock. The change + ** from SHARED to RESERVED marks the beginning of a normal + ** write operation (not a hot journal rollback). + */ + if( rc==SQLITE_OK + && pFile->eFileLock<=SHARED_LOCK + && eFileLock==RESERVED_LOCK + ){ + pFile->transCntrChng = 0; + pFile->dbUpdate = 0; + pFile->inNormalWrite = 1; + } +#endif + + + if( rc==SQLITE_OK ){ + pFile->eFileLock = eFileLock; + pInode->eFileLock = eFileLock; + }else if( eFileLock==EXCLUSIVE_LOCK ){ + pFile->eFileLock = PENDING_LOCK; + pInode->eFileLock = PENDING_LOCK; + } + +end_lock: + sqlite3_mutex_leave(pInode->pLockMutex); + OSTRACE(("LOCK %d %s %s (unix)\n", pFile->h, azFileLock(eFileLock), + rc==SQLITE_OK ? "ok" : "failed")); + return rc; +} + +/* +** Add the file descriptor used by file handle pFile to the corresponding +** pUnused list. +*/ +static void setPendingFd(unixFile *pFile){ + unixInodeInfo *pInode = pFile->pInode; + UnixUnusedFd *p = pFile->pPreallocatedUnused; + assert( unixFileMutexHeld(pFile) ); + p->pNext = pInode->pUnused; + pInode->pUnused = p; + pFile->h = -1; + pFile->pPreallocatedUnused = 0; +} + +/* +** Lower the locking level on file descriptor pFile to eFileLock. eFileLock +** must be either NO_LOCK or SHARED_LOCK. +** +** If the locking level of the file descriptor is already at or below +** the requested locking level, this routine is a no-op. +** +** If handleNFSUnlock is true, then on downgrading an EXCLUSIVE_LOCK to SHARED +** the byte range is divided into 2 parts and the first part is unlocked then +** set to a read lock, then the other part is simply unlocked. This works +** around a bug in BSD NFS lockd (also seen on MacOSX 10.3+) that fails to +** remove the write lock on a region when a read lock is set. +*/ +static int posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){ + unixFile *pFile = (unixFile*)id; + unixInodeInfo *pInode; + struct flock lock; + int rc = SQLITE_OK; + + assert( pFile ); + OSTRACE(("UNLOCK %d %d was %d(%d,%d) pid=%d (unix)\n", pFile->h, eFileLock, + pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared, + osGetpid(0))); + + assert( eFileLock<=SHARED_LOCK ); + if( pFile->eFileLock<=eFileLock ){ + return SQLITE_OK; + } + pInode = pFile->pInode; + sqlite3_mutex_enter(pInode->pLockMutex); + assert( pInode->nShared!=0 ); + if( pFile->eFileLock>SHARED_LOCK ){ + assert( pInode->eFileLock==pFile->eFileLock ); + +#ifdef SQLITE_DEBUG + /* When reducing a lock such that other processes can start + ** reading the database file again, make sure that the + ** transaction counter was updated if any part of the database + ** file changed. If the transaction counter is not updated, + ** other connections to the same file might not realize that + ** the file has changed and hence might not know to flush their + ** cache. The use of a stale cache can lead to database corruption. + */ + pFile->inNormalWrite = 0; +#endif + + /* downgrading to a shared lock on NFS involves clearing the write lock + ** before establishing the readlock - to avoid a race condition we downgrade + ** the lock in 2 blocks, so that part of the range will be covered by a + ** write lock until the rest is covered by a read lock: + ** 1: [WWWWW] + ** 2: [....W] + ** 3: [RRRRW] + ** 4: [RRRR.] + */ + if( eFileLock==SHARED_LOCK ){ +#if !defined(__APPLE__) || !SQLITE_ENABLE_LOCKING_STYLE + (void)handleNFSUnlock; + assert( handleNFSUnlock==0 ); +#endif +#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE + if( handleNFSUnlock ){ + int tErrno; /* Error code from system call errors */ + off_t divSize = SHARED_SIZE - 1; + + lock.l_type = F_UNLCK; + lock.l_whence = SEEK_SET; + lock.l_start = SHARED_FIRST; + lock.l_len = divSize; + if( unixFileLock(pFile, &lock)==(-1) ){ + tErrno = errno; + rc = SQLITE_IOERR_UNLOCK; + storeLastErrno(pFile, tErrno); + goto end_unlock; + } + lock.l_type = F_RDLCK; + lock.l_whence = SEEK_SET; + lock.l_start = SHARED_FIRST; + lock.l_len = divSize; + if( unixFileLock(pFile, &lock)==(-1) ){ + tErrno = errno; + rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK); + if( IS_LOCK_ERROR(rc) ){ + storeLastErrno(pFile, tErrno); + } + goto end_unlock; + } + lock.l_type = F_UNLCK; + lock.l_whence = SEEK_SET; + lock.l_start = SHARED_FIRST+divSize; + lock.l_len = SHARED_SIZE-divSize; + if( unixFileLock(pFile, &lock)==(-1) ){ + tErrno = errno; + rc = SQLITE_IOERR_UNLOCK; + storeLastErrno(pFile, tErrno); + goto end_unlock; + } + }else +#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ + { + lock.l_type = F_RDLCK; + lock.l_whence = SEEK_SET; + lock.l_start = SHARED_FIRST; + lock.l_len = SHARED_SIZE; + if( unixFileLock(pFile, &lock) ){ + /* In theory, the call to unixFileLock() cannot fail because another + ** process is holding an incompatible lock. If it does, this + ** indicates that the other process is not following the locking + ** protocol. If this happens, return SQLITE_IOERR_RDLOCK. Returning + ** SQLITE_BUSY would confuse the upper layer (in practice it causes + ** an assert to fail). */ + rc = SQLITE_IOERR_RDLOCK; + storeLastErrno(pFile, errno); + goto end_unlock; + } + } + } + lock.l_type = F_UNLCK; + lock.l_whence = SEEK_SET; + lock.l_start = PENDING_BYTE; + lock.l_len = 2L; assert( PENDING_BYTE+1==RESERVED_BYTE ); + if( unixFileLock(pFile, &lock)==0 ){ + pInode->eFileLock = SHARED_LOCK; + }else{ + rc = SQLITE_IOERR_UNLOCK; + storeLastErrno(pFile, errno); + goto end_unlock; + } + } + if( eFileLock==NO_LOCK ){ + /* Decrement the shared lock counter. Release the lock using an + ** OS call only when all threads in this same process have released + ** the lock. + */ + pInode->nShared--; + if( pInode->nShared==0 ){ + lock.l_type = F_UNLCK; + lock.l_whence = SEEK_SET; + lock.l_start = lock.l_len = 0L; + if( unixFileLock(pFile, &lock)==0 ){ + pInode->eFileLock = NO_LOCK; + }else{ + rc = SQLITE_IOERR_UNLOCK; + storeLastErrno(pFile, errno); + pInode->eFileLock = NO_LOCK; + pFile->eFileLock = NO_LOCK; + } + } + + /* Decrement the count of locks against this same file. When the + ** count reaches zero, close any other file descriptors whose close + ** was deferred because of outstanding locks. + */ + pInode->nLock--; + assert( pInode->nLock>=0 ); + if( pInode->nLock==0 ) closePendingFds(pFile); + } + +end_unlock: + sqlite3_mutex_leave(pInode->pLockMutex); + if( rc==SQLITE_OK ){ + pFile->eFileLock = eFileLock; + } + return rc; +} + +/* +** Lower the locking level on file descriptor pFile to eFileLock. eFileLock +** must be either NO_LOCK or SHARED_LOCK. +** +** If the locking level of the file descriptor is already at or below +** the requested locking level, this routine is a no-op. +*/ +static int unixUnlock(sqlite3_file *id, int eFileLock){ +#if SQLITE_MAX_MMAP_SIZE>0 + assert( eFileLock==SHARED_LOCK || ((unixFile *)id)->nFetchOut==0 ); +#endif + return posixUnlock(id, eFileLock, 0); +} + +#if SQLITE_MAX_MMAP_SIZE>0 +static int unixMapfile(unixFile *pFd, i64 nByte); +static void unixUnmapfile(unixFile *pFd); +#endif + +/* +** This function performs the parts of the "close file" operation +** common to all locking schemes. It closes the directory and file +** handles, if they are valid, and sets all fields of the unixFile +** structure to 0. +** +** It is *not* necessary to hold the mutex when this routine is called, +** even on VxWorks. A mutex will be acquired on VxWorks by the +** vxworksReleaseFileId() routine. +*/ +static int closeUnixFile(sqlite3_file *id){ + unixFile *pFile = (unixFile*)id; +#if SQLITE_MAX_MMAP_SIZE>0 + unixUnmapfile(pFile); +#endif + if( pFile->h>=0 ){ + robust_close(pFile, pFile->h, __LINE__); + pFile->h = -1; + } +#if OS_VXWORKS + if( pFile->pId ){ + if( pFile->ctrlFlags & UNIXFILE_DELETE ){ + osUnlink(pFile->pId->zCanonicalName); + } + vxworksReleaseFileId(pFile->pId); + pFile->pId = 0; + } +#endif +#ifdef SQLITE_UNLINK_AFTER_CLOSE + if( pFile->ctrlFlags & UNIXFILE_DELETE ){ + osUnlink(pFile->zPath); + sqlite3_free(*(char**)&pFile->zPath); + pFile->zPath = 0; + } +#endif + OSTRACE(("CLOSE %-3d\n", pFile->h)); + OpenCounter(-1); + sqlite3_free(pFile->pPreallocatedUnused); + memset(pFile, 0, sizeof(unixFile)); + return SQLITE_OK; +} + +/* +** Close a file. +*/ +static int unixClose(sqlite3_file *id){ + int rc = SQLITE_OK; + unixFile *pFile = (unixFile *)id; + unixInodeInfo *pInode = pFile->pInode; + + assert( pInode!=0 ); + verifyDbFile(pFile); + unixUnlock(id, NO_LOCK); + assert( unixFileMutexNotheld(pFile) ); + unixEnterMutex(); + + /* unixFile.pInode is always valid here. Otherwise, a different close + ** routine (e.g. nolockClose()) would be called instead. + */ + assert( pFile->pInode->nLock>0 || pFile->pInode->bProcessLock==0 ); + sqlite3_mutex_enter(pInode->pLockMutex); + if( pInode->nLock ){ + /* If there are outstanding locks, do not actually close the file just + ** yet because that would clear those locks. Instead, add the file + ** descriptor to pInode->pUnused list. It will be automatically closed + ** when the last lock is cleared. + */ + setPendingFd(pFile); + } + sqlite3_mutex_leave(pInode->pLockMutex); + releaseInodeInfo(pFile); + assert( pFile->pShm==0 ); + rc = closeUnixFile(id); + unixLeaveMutex(); + return rc; +} + +/************** End of the posix advisory lock implementation ***************** +******************************************************************************/ + +/****************************************************************************** +****************************** No-op Locking ********************************** +** +** Of the various locking implementations available, this is by far the +** simplest: locking is ignored. No attempt is made to lock the database +** file for reading or writing. +** +** This locking mode is appropriate for use on read-only databases +** (ex: databases that are burned into CD-ROM, for example.) It can +** also be used if the application employs some external mechanism to +** prevent simultaneous access of the same database by two or more +** database connections. But there is a serious risk of database +** corruption if this locking mode is used in situations where multiple +** database connections are accessing the same database file at the same +** time and one or more of those connections are writing. +*/ + +static int nolockCheckReservedLock(sqlite3_file *NotUsed, int *pResOut){ + UNUSED_PARAMETER(NotUsed); + *pResOut = 0; + return SQLITE_OK; +} +static int nolockLock(sqlite3_file *NotUsed, int NotUsed2){ + UNUSED_PARAMETER2(NotUsed, NotUsed2); + return SQLITE_OK; +} +static int nolockUnlock(sqlite3_file *NotUsed, int NotUsed2){ + UNUSED_PARAMETER2(NotUsed, NotUsed2); + return SQLITE_OK; +} + +/* +** Close the file. +*/ +static int nolockClose(sqlite3_file *id) { + return closeUnixFile(id); +} + +/******************* End of the no-op lock implementation ********************* +******************************************************************************/ + +/****************************************************************************** +************************* Begin dot-file Locking ****************************** +** +** The dotfile locking implementation uses the existence of separate lock +** files (really a directory) to control access to the database. This works +** on just about every filesystem imaginable. But there are serious downsides: +** +** (1) There is zero concurrency. A single reader blocks all other +** connections from reading or writing the database. +** +** (2) An application crash or power loss can leave stale lock files +** sitting around that need to be cleared manually. +** +** Nevertheless, a dotlock is an appropriate locking mode for use if no +** other locking strategy is available. +** +** Dotfile locking works by creating a subdirectory in the same directory as +** the database and with the same name but with a ".lock" extension added. +** The existence of a lock directory implies an EXCLUSIVE lock. All other +** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE. +*/ + +/* +** The file suffix added to the data base filename in order to create the +** lock directory. +*/ +#define DOTLOCK_SUFFIX ".lock" + +/* +** This routine checks if there is a RESERVED lock held on the specified +** file by this or any other process. If such a lock is held, set *pResOut +** to a non-zero value otherwise *pResOut is set to zero. The return value +** is set to SQLITE_OK unless an I/O error occurs during lock checking. +** +** In dotfile locking, either a lock exists or it does not. So in this +** variation of CheckReservedLock(), *pResOut is set to true if any lock +** is held on the file and false if the file is unlocked. +*/ +static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) { + int rc = SQLITE_OK; + int reserved = 0; + unixFile *pFile = (unixFile*)id; + + SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); + + assert( pFile ); + reserved = osAccess((const char*)pFile->lockingContext, 0)==0; + OSTRACE(("TEST WR-LOCK %d %d %d (dotlock)\n", pFile->h, rc, reserved)); + *pResOut = reserved; + return rc; +} + +/* +** Lock the file with the lock specified by parameter eFileLock - one +** of the following: +** +** (1) SHARED_LOCK +** (2) RESERVED_LOCK +** (3) PENDING_LOCK +** (4) EXCLUSIVE_LOCK +** +** Sometimes when requesting one lock state, additional lock states +** are inserted in between. The locking might fail on one of the later +** transitions leaving the lock state different from what it started but +** still short of its goal. The following chart shows the allowed +** transitions and the inserted intermediate states: +** +** UNLOCKED -> SHARED +** SHARED -> RESERVED +** SHARED -> (PENDING) -> EXCLUSIVE +** RESERVED -> (PENDING) -> EXCLUSIVE +** PENDING -> EXCLUSIVE +** +** This routine will only increase a lock. Use the sqlite3OsUnlock() +** routine to lower a locking level. +** +** With dotfile locking, we really only support state (4): EXCLUSIVE. +** But we track the other locking levels internally. +*/ +static int dotlockLock(sqlite3_file *id, int eFileLock) { + unixFile *pFile = (unixFile*)id; + char *zLockFile = (char *)pFile->lockingContext; + int rc = SQLITE_OK; + + + /* If we have any lock, then the lock file already exists. All we have + ** to do is adjust our internal record of the lock level. + */ + if( pFile->eFileLock > NO_LOCK ){ + pFile->eFileLock = eFileLock; + /* Always update the timestamp on the old file */ +#ifdef HAVE_UTIME + utime(zLockFile, NULL); +#else + utimes(zLockFile, NULL); +#endif + return SQLITE_OK; + } + + /* grab an exclusive lock */ + rc = osMkdir(zLockFile, 0777); + if( rc<0 ){ + /* failed to open/create the lock directory */ + int tErrno = errno; + if( EEXIST == tErrno ){ + rc = SQLITE_BUSY; + } else { + rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); + if( rc!=SQLITE_BUSY ){ + storeLastErrno(pFile, tErrno); + } + } + return rc; + } + + /* got it, set the type and return ok */ + pFile->eFileLock = eFileLock; + return rc; +} + +/* +** Lower the locking level on file descriptor pFile to eFileLock. eFileLock +** must be either NO_LOCK or SHARED_LOCK. +** +** If the locking level of the file descriptor is already at or below +** the requested locking level, this routine is a no-op. +** +** When the locking level reaches NO_LOCK, delete the lock file. +*/ +static int dotlockUnlock(sqlite3_file *id, int eFileLock) { + unixFile *pFile = (unixFile*)id; + char *zLockFile = (char *)pFile->lockingContext; + int rc; + + assert( pFile ); + OSTRACE(("UNLOCK %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock, + pFile->eFileLock, osGetpid(0))); + assert( eFileLock<=SHARED_LOCK ); + + /* no-op if possible */ + if( pFile->eFileLock==eFileLock ){ + return SQLITE_OK; + } + + /* To downgrade to shared, simply update our internal notion of the + ** lock state. No need to mess with the file on disk. + */ + if( eFileLock==SHARED_LOCK ){ + pFile->eFileLock = SHARED_LOCK; + return SQLITE_OK; + } + + /* To fully unlock the database, delete the lock file */ + assert( eFileLock==NO_LOCK ); + rc = osRmdir(zLockFile); + if( rc<0 ){ + int tErrno = errno; + if( tErrno==ENOENT ){ + rc = SQLITE_OK; + }else{ + rc = SQLITE_IOERR_UNLOCK; + storeLastErrno(pFile, tErrno); + } + return rc; + } + pFile->eFileLock = NO_LOCK; + return SQLITE_OK; +} + +/* +** Close a file. Make sure the lock has been released before closing. +*/ +static int dotlockClose(sqlite3_file *id) { + unixFile *pFile = (unixFile*)id; + assert( id!=0 ); + dotlockUnlock(id, NO_LOCK); + sqlite3_free(pFile->lockingContext); + return closeUnixFile(id); +} +/****************** End of the dot-file lock implementation ******************* +******************************************************************************/ + +/****************************************************************************** +************************** Begin flock Locking ******************************** +** +** Use the flock() system call to do file locking. +** +** flock() locking is like dot-file locking in that the various +** fine-grain locking levels supported by SQLite are collapsed into +** a single exclusive lock. In other words, SHARED, RESERVED, and +** PENDING locks are the same thing as an EXCLUSIVE lock. SQLite +** still works when you do this, but concurrency is reduced since +** only a single process can be reading the database at a time. +** +** Omit this section if SQLITE_ENABLE_LOCKING_STYLE is turned off +*/ +#if SQLITE_ENABLE_LOCKING_STYLE + +/* +** Retry flock() calls that fail with EINTR +*/ +#ifdef EINTR +static int robust_flock(int fd, int op){ + int rc; + do{ rc = flock(fd,op); }while( rc<0 && errno==EINTR ); + return rc; +} +#else +# define robust_flock(a,b) flock(a,b) +#endif + + +/* +** This routine checks if there is a RESERVED lock held on the specified +** file by this or any other process. If such a lock is held, set *pResOut +** to a non-zero value otherwise *pResOut is set to zero. The return value +** is set to SQLITE_OK unless an I/O error occurs during lock checking. +*/ +static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){ + int rc = SQLITE_OK; + int reserved = 0; + unixFile *pFile = (unixFile*)id; + + SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); + + assert( pFile ); + + /* Check if a thread in this process holds such a lock */ + if( pFile->eFileLock>SHARED_LOCK ){ + reserved = 1; + } + + /* Otherwise see if some other process holds it. */ + if( !reserved ){ + /* attempt to get the lock */ + int lrc = robust_flock(pFile->h, LOCK_EX | LOCK_NB); + if( !lrc ){ + /* got the lock, unlock it */ + lrc = robust_flock(pFile->h, LOCK_UN); + if ( lrc ) { + int tErrno = errno; + /* unlock failed with an error */ + lrc = SQLITE_IOERR_UNLOCK; + storeLastErrno(pFile, tErrno); + rc = lrc; + } + } else { + int tErrno = errno; + reserved = 1; + /* someone else might have it reserved */ + lrc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); + if( IS_LOCK_ERROR(lrc) ){ + storeLastErrno(pFile, tErrno); + rc = lrc; + } + } + } + OSTRACE(("TEST WR-LOCK %d %d %d (flock)\n", pFile->h, rc, reserved)); + +#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS + if( (rc & 0xff) == SQLITE_IOERR ){ + rc = SQLITE_OK; + reserved=1; + } +#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */ + *pResOut = reserved; + return rc; +} + +/* +** Lock the file with the lock specified by parameter eFileLock - one +** of the following: +** +** (1) SHARED_LOCK +** (2) RESERVED_LOCK +** (3) PENDING_LOCK +** (4) EXCLUSIVE_LOCK +** +** Sometimes when requesting one lock state, additional lock states +** are inserted in between. The locking might fail on one of the later +** transitions leaving the lock state different from what it started but +** still short of its goal. The following chart shows the allowed +** transitions and the inserted intermediate states: +** +** UNLOCKED -> SHARED +** SHARED -> RESERVED +** SHARED -> (PENDING) -> EXCLUSIVE +** RESERVED -> (PENDING) -> EXCLUSIVE +** PENDING -> EXCLUSIVE +** +** flock() only really support EXCLUSIVE locks. We track intermediate +** lock states in the sqlite3_file structure, but all locks SHARED or +** above are really EXCLUSIVE locks and exclude all other processes from +** access the file. +** +** This routine will only increase a lock. Use the sqlite3OsUnlock() +** routine to lower a locking level. +*/ +static int flockLock(sqlite3_file *id, int eFileLock) { + int rc = SQLITE_OK; + unixFile *pFile = (unixFile*)id; + + assert( pFile ); + + /* if we already have a lock, it is exclusive. + ** Just adjust level and punt on outta here. */ + if (pFile->eFileLock > NO_LOCK) { + pFile->eFileLock = eFileLock; + return SQLITE_OK; + } + + /* grab an exclusive lock */ + + if (robust_flock(pFile->h, LOCK_EX | LOCK_NB)) { + int tErrno = errno; + /* didn't get, must be busy */ + rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK); + if( IS_LOCK_ERROR(rc) ){ + storeLastErrno(pFile, tErrno); + } + } else { + /* got it, set the type and return ok */ + pFile->eFileLock = eFileLock; + } + OSTRACE(("LOCK %d %s %s (flock)\n", pFile->h, azFileLock(eFileLock), + rc==SQLITE_OK ? "ok" : "failed")); +#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS + if( (rc & 0xff) == SQLITE_IOERR ){ + rc = SQLITE_BUSY; + } +#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */ + return rc; +} + + +/* +** Lower the locking level on file descriptor pFile to eFileLock. eFileLock +** must be either NO_LOCK or SHARED_LOCK. +** +** If the locking level of the file descriptor is already at or below +** the requested locking level, this routine is a no-op. +*/ +static int flockUnlock(sqlite3_file *id, int eFileLock) { + unixFile *pFile = (unixFile*)id; + + assert( pFile ); + OSTRACE(("UNLOCK %d %d was %d pid=%d (flock)\n", pFile->h, eFileLock, + pFile->eFileLock, osGetpid(0))); + assert( eFileLock<=SHARED_LOCK ); + + /* no-op if possible */ + if( pFile->eFileLock==eFileLock ){ + return SQLITE_OK; + } + + /* shared can just be set because we always have an exclusive */ + if (eFileLock==SHARED_LOCK) { + pFile->eFileLock = eFileLock; + return SQLITE_OK; + } + + /* no, really, unlock. */ + if( robust_flock(pFile->h, LOCK_UN) ){ +#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS + return SQLITE_OK; +#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */ + return SQLITE_IOERR_UNLOCK; + }else{ + pFile->eFileLock = NO_LOCK; + return SQLITE_OK; + } +} + +/* +** Close a file. +*/ +static int flockClose(sqlite3_file *id) { + assert( id!=0 ); + flockUnlock(id, NO_LOCK); + return closeUnixFile(id); +} + +#endif /* SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORK */ + +/******************* End of the flock lock implementation ********************* +******************************************************************************/ + +/****************************************************************************** +************************ Begin Named Semaphore Locking ************************ +** +** Named semaphore locking is only supported on VxWorks. +** +** Semaphore locking is like dot-lock and flock in that it really only +** supports EXCLUSIVE locking. Only a single process can read or write +** the database file at a time. This reduces potential concurrency, but +** makes the lock implementation much easier. +*/ +#if OS_VXWORKS + +/* +** This routine checks if there is a RESERVED lock held on the specified +** file by this or any other process. If such a lock is held, set *pResOut +** to a non-zero value otherwise *pResOut is set to zero. The return value +** is set to SQLITE_OK unless an I/O error occurs during lock checking. +*/ +static int semXCheckReservedLock(sqlite3_file *id, int *pResOut) { + int rc = SQLITE_OK; + int reserved = 0; + unixFile *pFile = (unixFile*)id; + + SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); + + assert( pFile ); + + /* Check if a thread in this process holds such a lock */ + if( pFile->eFileLock>SHARED_LOCK ){ + reserved = 1; + } + + /* Otherwise see if some other process holds it. */ + if( !reserved ){ + sem_t *pSem = pFile->pInode->pSem; + + if( sem_trywait(pSem)==-1 ){ + int tErrno = errno; + if( EAGAIN != tErrno ){ + rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK); + storeLastErrno(pFile, tErrno); + } else { + /* someone else has the lock when we are in NO_LOCK */ + reserved = (pFile->eFileLock < SHARED_LOCK); + } + }else{ + /* we could have it if we want it */ + sem_post(pSem); + } + } + OSTRACE(("TEST WR-LOCK %d %d %d (sem)\n", pFile->h, rc, reserved)); + + *pResOut = reserved; + return rc; +} + +/* +** Lock the file with the lock specified by parameter eFileLock - one +** of the following: +** +** (1) SHARED_LOCK +** (2) RESERVED_LOCK +** (3) PENDING_LOCK +** (4) EXCLUSIVE_LOCK +** +** Sometimes when requesting one lock state, additional lock states +** are inserted in between. The locking might fail on one of the later +** transitions leaving the lock state different from what it started but +** still short of its goal. The following chart shows the allowed +** transitions and the inserted intermediate states: +** +** UNLOCKED -> SHARED +** SHARED -> RESERVED +** SHARED -> (PENDING) -> EXCLUSIVE +** RESERVED -> (PENDING) -> EXCLUSIVE +** PENDING -> EXCLUSIVE +** +** Semaphore locks only really support EXCLUSIVE locks. We track intermediate +** lock states in the sqlite3_file structure, but all locks SHARED or +** above are really EXCLUSIVE locks and exclude all other processes from +** access the file. +** +** This routine will only increase a lock. Use the sqlite3OsUnlock() +** routine to lower a locking level. +*/ +static int semXLock(sqlite3_file *id, int eFileLock) { + unixFile *pFile = (unixFile*)id; + sem_t *pSem = pFile->pInode->pSem; + int rc = SQLITE_OK; + + /* if we already have a lock, it is exclusive. + ** Just adjust level and punt on outta here. */ + if (pFile->eFileLock > NO_LOCK) { + pFile->eFileLock = eFileLock; + rc = SQLITE_OK; + goto sem_end_lock; + } + + /* lock semaphore now but bail out when already locked. */ + if( sem_trywait(pSem)==-1 ){ + rc = SQLITE_BUSY; + goto sem_end_lock; + } + + /* got it, set the type and return ok */ + pFile->eFileLock = eFileLock; + + sem_end_lock: + return rc; +} + +/* +** Lower the locking level on file descriptor pFile to eFileLock. eFileLock +** must be either NO_LOCK or SHARED_LOCK. +** +** If the locking level of the file descriptor is already at or below +** the requested locking level, this routine is a no-op. +*/ +static int semXUnlock(sqlite3_file *id, int eFileLock) { + unixFile *pFile = (unixFile*)id; + sem_t *pSem = pFile->pInode->pSem; + + assert( pFile ); + assert( pSem ); + OSTRACE(("UNLOCK %d %d was %d pid=%d (sem)\n", pFile->h, eFileLock, + pFile->eFileLock, osGetpid(0))); + assert( eFileLock<=SHARED_LOCK ); + + /* no-op if possible */ + if( pFile->eFileLock==eFileLock ){ + return SQLITE_OK; + } + + /* shared can just be set because we always have an exclusive */ + if (eFileLock==SHARED_LOCK) { + pFile->eFileLock = eFileLock; + return SQLITE_OK; + } + + /* no, really unlock. */ + if ( sem_post(pSem)==-1 ) { + int rc, tErrno = errno; + rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK); + if( IS_LOCK_ERROR(rc) ){ + storeLastErrno(pFile, tErrno); + } + return rc; + } + pFile->eFileLock = NO_LOCK; + return SQLITE_OK; +} + +/* + ** Close a file. + */ +static int semXClose(sqlite3_file *id) { + if( id ){ + unixFile *pFile = (unixFile*)id; + semXUnlock(id, NO_LOCK); + assert( pFile ); + assert( unixFileMutexNotheld(pFile) ); + unixEnterMutex(); + releaseInodeInfo(pFile); + unixLeaveMutex(); + closeUnixFile(id); + } + return SQLITE_OK; +} + +#endif /* OS_VXWORKS */ +/* +** Named semaphore locking is only available on VxWorks. +** +*************** End of the named semaphore lock implementation **************** +******************************************************************************/ + + +/****************************************************************************** +*************************** Begin AFP Locking ********************************* +** +** AFP is the Apple Filing Protocol. AFP is a network filesystem found +** on Apple Macintosh computers - both OS9 and OSX. +** +** Third-party implementations of AFP are available. But this code here +** only works on OSX. +*/ + +#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE +/* +** The afpLockingContext structure contains all afp lock specific state +*/ +typedef struct afpLockingContext afpLockingContext; +struct afpLockingContext { + int reserved; + const char *dbPath; /* Name of the open file */ +}; + +struct ByteRangeLockPB2 +{ + unsigned long long offset; /* offset to first byte to lock */ + unsigned long long length; /* nbr of bytes to lock */ + unsigned long long retRangeStart; /* nbr of 1st byte locked if successful */ + unsigned char unLockFlag; /* 1 = unlock, 0 = lock */ + unsigned char startEndFlag; /* 1=rel to end of fork, 0=rel to start */ + int fd; /* file desc to assoc this lock with */ +}; + +#define afpfsByteRangeLock2FSCTL _IOWR('z', 23, struct ByteRangeLockPB2) + +/* +** This is a utility for setting or clearing a bit-range lock on an +** AFP filesystem. +** +** Return SQLITE_OK on success, SQLITE_BUSY on failure. +*/ +static int afpSetLock( + const char *path, /* Name of the file to be locked or unlocked */ + unixFile *pFile, /* Open file descriptor on path */ + unsigned long long offset, /* First byte to be locked */ + unsigned long long length, /* Number of bytes to lock */ + int setLockFlag /* True to set lock. False to clear lock */ +){ + struct ByteRangeLockPB2 pb; + int err; + + pb.unLockFlag = setLockFlag ? 0 : 1; + pb.startEndFlag = 0; + pb.offset = offset; + pb.length = length; + pb.fd = pFile->h; + + OSTRACE(("AFPSETLOCK [%s] for %d%s in range %llx:%llx\n", + (setLockFlag?"ON":"OFF"), pFile->h, (pb.fd==-1?"[testval-1]":""), + offset, length)); + err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0); + if ( err==-1 ) { + int rc; + int tErrno = errno; + OSTRACE(("AFPSETLOCK failed to fsctl() '%s' %d %s\n", + path, tErrno, strerror(tErrno))); +#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS + rc = SQLITE_BUSY; +#else + rc = sqliteErrorFromPosixError(tErrno, + setLockFlag ? SQLITE_IOERR_LOCK : SQLITE_IOERR_UNLOCK); +#endif /* SQLITE_IGNORE_AFP_LOCK_ERRORS */ + if( IS_LOCK_ERROR(rc) ){ + storeLastErrno(pFile, tErrno); + } + return rc; + } else { + return SQLITE_OK; + } +} + +/* +** This routine checks if there is a RESERVED lock held on the specified +** file by this or any other process. If such a lock is held, set *pResOut +** to a non-zero value otherwise *pResOut is set to zero. The return value +** is set to SQLITE_OK unless an I/O error occurs during lock checking. +*/ +static int afpCheckReservedLock(sqlite3_file *id, int *pResOut){ + int rc = SQLITE_OK; + int reserved = 0; + unixFile *pFile = (unixFile*)id; + afpLockingContext *context; + + SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; ); + + assert( pFile ); + context = (afpLockingContext *) pFile->lockingContext; + if( context->reserved ){ + *pResOut = 1; + return SQLITE_OK; + } + sqlite3_mutex_enter(pFile->pInode->pLockMutex); + /* Check if a thread in this process holds such a lock */ + if( pFile->pInode->eFileLock>SHARED_LOCK ){ + reserved = 1; + } + + /* Otherwise see if some other process holds it. + */ + if( !reserved ){ + /* lock the RESERVED byte */ + int lrc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1); + if( SQLITE_OK==lrc ){ + /* if we succeeded in taking the reserved lock, unlock it to restore + ** the original state */ + lrc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0); + } else { + /* if we failed to get the lock then someone else must have it */ + reserved = 1; + } + if( IS_LOCK_ERROR(lrc) ){ + rc=lrc; + } + } + + sqlite3_mutex_leave(pFile->pInode->pLockMutex); + OSTRACE(("TEST WR-LOCK %d %d %d (afp)\n", pFile->h, rc, reserved)); + + *pResOut = reserved; + return rc; +} + +/* +** Lock the file with the lock specified by parameter eFileLock - one +** of the following: +** +** (1) SHARED_LOCK +** (2) RESERVED_LOCK +** (3) PENDING_LOCK +** (4) EXCLUSIVE_LOCK +** +** Sometimes when requesting one lock state, additional lock states +** are inserted in between. The locking might fail on one of the later +** transitions leaving the lock state different from what it started but +** still short of its goal. The following chart shows the allowed +** transitions and the inserted intermediate states: +** +** UNLOCKED -> SHARED +** SHARED -> RESERVED +** SHARED -> (PENDING) -> EXCLUSIVE +** RESERVED -> (PENDING) -> EXCLUSIVE +** PENDING -> EXCLUSIVE +** +** This routine will only increase a lock. Use the sqlite3OsUnlock() +** routine to lower a locking level. +*/ +static int afpLock(sqlite3_file *id, int eFileLock){ + int rc = SQLITE_OK; + unixFile *pFile = (unixFile*)id; + unixInodeInfo *pInode = pFile->pInode; + afpLockingContext *context = (afpLockingContext *) pFile->lockingContext; + + assert( pFile ); + OSTRACE(("LOCK %d %s was %s(%s,%d) pid=%d (afp)\n", pFile->h, + azFileLock(eFileLock), azFileLock(pFile->eFileLock), + azFileLock(pInode->eFileLock), pInode->nShared , osGetpid(0))); + + /* If there is already a lock of this type or more restrictive on the + ** unixFile, do nothing. Don't use the afp_end_lock: exit path, as + ** unixEnterMutex() hasn't been called yet. + */ + if( pFile->eFileLock>=eFileLock ){ + OSTRACE(("LOCK %d %s ok (already held) (afp)\n", pFile->h, + azFileLock(eFileLock))); + return SQLITE_OK; + } + + /* Make sure the locking sequence is correct + ** (1) We never move from unlocked to anything higher than shared lock. + ** (2) SQLite never explicitly requests a pendig lock. + ** (3) A shared lock is always held when a reserve lock is requested. + */ + assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK ); + assert( eFileLock!=PENDING_LOCK ); + assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK ); + + /* This mutex is needed because pFile->pInode is shared across threads + */ + pInode = pFile->pInode; + sqlite3_mutex_enter(pInode->pLockMutex); + + /* If some thread using this PID has a lock via a different unixFile* + ** handle that precludes the requested lock, return BUSY. + */ + if( (pFile->eFileLock!=pInode->eFileLock && + (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK)) + ){ + rc = SQLITE_BUSY; + goto afp_end_lock; + } + + /* If a SHARED lock is requested, and some thread using this PID already + ** has a SHARED or RESERVED lock, then increment reference counts and + ** return SQLITE_OK. + */ + if( eFileLock==SHARED_LOCK && + (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){ + assert( eFileLock==SHARED_LOCK ); + assert( pFile->eFileLock==0 ); + assert( pInode->nShared>0 ); + pFile->eFileLock = SHARED_LOCK; + pInode->nShared++; + pInode->nLock++; + goto afp_end_lock; + } + + /* A PENDING lock is needed before acquiring a SHARED lock and before + ** acquiring an EXCLUSIVE lock. For the SHARED lock, the PENDING will + ** be released. + */ + if( eFileLock==SHARED_LOCK + || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK) + ){ + int failed; + failed = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 1); + if (failed) { + rc = failed; + goto afp_end_lock; + } + } + + /* If control gets to this point, then actually go ahead and make + ** operating system calls for the specified lock. + */ + if( eFileLock==SHARED_LOCK ){ + int lrc1, lrc2, lrc1Errno = 0; + long lk, mask; + + assert( pInode->nShared==0 ); + assert( pInode->eFileLock==0 ); + + mask = (sizeof(long)==8) ? LARGEST_INT64 : 0x7fffffff; + /* Now get the read-lock SHARED_LOCK */ + /* note that the quality of the randomness doesn't matter that much */ + lk = random(); + pInode->sharedByte = (lk & mask)%(SHARED_SIZE - 1); + lrc1 = afpSetLock(context->dbPath, pFile, + SHARED_FIRST+pInode->sharedByte, 1, 1); + if( IS_LOCK_ERROR(lrc1) ){ + lrc1Errno = pFile->lastErrno; + } + /* Drop the temporary PENDING lock */ + lrc2 = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0); + + if( IS_LOCK_ERROR(lrc1) ) { + storeLastErrno(pFile, lrc1Errno); + rc = lrc1; + goto afp_end_lock; + } else if( IS_LOCK_ERROR(lrc2) ){ + rc = lrc2; + goto afp_end_lock; + } else if( lrc1 != SQLITE_OK ) { + rc = lrc1; + } else { + pFile->eFileLock = SHARED_LOCK; + pInode->nLock++; + pInode->nShared = 1; + } + }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){ + /* We are trying for an exclusive lock but another thread in this + ** same process is still holding a shared lock. */ + rc = SQLITE_BUSY; + }else{ + /* The request was for a RESERVED or EXCLUSIVE lock. It is + ** assumed that there is a SHARED or greater lock on the file + ** already. + */ + int failed = 0; + assert( 0!=pFile->eFileLock ); + if (eFileLock >= RESERVED_LOCK && pFile->eFileLock < RESERVED_LOCK) { + /* Acquire a RESERVED lock */ + failed = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1); + if( !failed ){ + context->reserved = 1; + } + } + if (!failed && eFileLock == EXCLUSIVE_LOCK) { + /* Acquire an EXCLUSIVE lock */ + + /* Remove the shared lock before trying the range. we'll need to + ** reestablish the shared lock if we can't get the afpUnlock + */ + if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST + + pInode->sharedByte, 1, 0)) ){ + int failed2 = SQLITE_OK; + /* now attemmpt to get the exclusive lock range */ + failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST, + SHARED_SIZE, 1); + if( failed && (failed2 = afpSetLock(context->dbPath, pFile, + SHARED_FIRST + pInode->sharedByte, 1, 1)) ){ + /* Can't reestablish the shared lock. Sqlite can't deal, this is + ** a critical I/O error + */ + rc = ((failed & 0xff) == SQLITE_IOERR) ? failed2 : + SQLITE_IOERR_LOCK; + goto afp_end_lock; + } + }else{ + rc = failed; + } + } + if( failed ){ + rc = failed; + } + } + + if( rc==SQLITE_OK ){ + pFile->eFileLock = eFileLock; + pInode->eFileLock = eFileLock; + }else if( eFileLock==EXCLUSIVE_LOCK ){ + pFile->eFileLock = PENDING_LOCK; + pInode->eFileLock = PENDING_LOCK; + } + +afp_end_lock: + sqlite3_mutex_leave(pInode->pLockMutex); + OSTRACE(("LOCK %d %s %s (afp)\n", pFile->h, azFileLock(eFileLock), + rc==SQLITE_OK ? "ok" : "failed")); + return rc; +} + +/* +** Lower the locking level on file descriptor pFile to eFileLock. eFileLock +** must be either NO_LOCK or SHARED_LOCK. +** +** If the locking level of the file descriptor is already at or below +** the requested locking level, this routine is a no-op. +*/ +static int afpUnlock(sqlite3_file *id, int eFileLock) { + int rc = SQLITE_OK; + unixFile *pFile = (unixFile*)id; + unixInodeInfo *pInode; + afpLockingContext *context = (afpLockingContext *) pFile->lockingContext; + int skipShared = 0; +#ifdef SQLITE_TEST + int h = pFile->h; +#endif + + assert( pFile ); + OSTRACE(("UNLOCK %d %d was %d(%d,%d) pid=%d (afp)\n", pFile->h, eFileLock, + pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared, + osGetpid(0))); + + assert( eFileLock<=SHARED_LOCK ); + if( pFile->eFileLock<=eFileLock ){ + return SQLITE_OK; + } + pInode = pFile->pInode; + sqlite3_mutex_enter(pInode->pLockMutex); + assert( pInode->nShared!=0 ); + if( pFile->eFileLock>SHARED_LOCK ){ + assert( pInode->eFileLock==pFile->eFileLock ); + SimulateIOErrorBenign(1); + SimulateIOError( h=(-1) ) + SimulateIOErrorBenign(0); + +#ifdef SQLITE_DEBUG + /* When reducing a lock such that other processes can start + ** reading the database file again, make sure that the + ** transaction counter was updated if any part of the database + ** file changed. If the transaction counter is not updated, + ** other connections to the same file might not realize that + ** the file has changed and hence might not know to flush their + ** cache. The use of a stale cache can lead to database corruption. + */ + assert( pFile->inNormalWrite==0 + || pFile->dbUpdate==0 + || pFile->transCntrChng==1 ); + pFile->inNormalWrite = 0; +#endif + + if( pFile->eFileLock==EXCLUSIVE_LOCK ){ + rc = afpSetLock(context->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0); + if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1) ){ + /* only re-establish the shared lock if necessary */ + int sharedLockByte = SHARED_FIRST+pInode->sharedByte; + rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 1); + } else { + skipShared = 1; + } + } + if( rc==SQLITE_OK && pFile->eFileLock>=PENDING_LOCK ){ + rc = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0); + } + if( rc==SQLITE_OK && pFile->eFileLock>=RESERVED_LOCK && context->reserved ){ + rc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0); + if( !rc ){ + context->reserved = 0; + } + } + if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1)){ + pInode->eFileLock = SHARED_LOCK; + } + } + if( rc==SQLITE_OK && eFileLock==NO_LOCK ){ + + /* Decrement the shared lock counter. Release the lock using an + ** OS call only when all threads in this same process have released + ** the lock. + */ + unsigned long long sharedLockByte = SHARED_FIRST+pInode->sharedByte; + pInode->nShared--; + if( pInode->nShared==0 ){ + SimulateIOErrorBenign(1); + SimulateIOError( h=(-1) ) + SimulateIOErrorBenign(0); + if( !skipShared ){ + rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 0); + } + if( !rc ){ + pInode->eFileLock = NO_LOCK; + pFile->eFileLock = NO_LOCK; + } + } + if( rc==SQLITE_OK ){ + pInode->nLock--; + assert( pInode->nLock>=0 ); + if( pInode->nLock==0 ) closePendingFds(pFile); + } + } + + sqlite3_mutex_leave(pInode->pLockMutex); + if( rc==SQLITE_OK ){ + pFile->eFileLock = eFileLock; + } + return rc; +} + +/* +** Close a file & cleanup AFP specific locking context +*/ +static int afpClose(sqlite3_file *id) { + int rc = SQLITE_OK; + unixFile *pFile = (unixFile*)id; + assert( id!=0 ); + afpUnlock(id, NO_LOCK); + assert( unixFileMutexNotheld(pFile) ); + unixEnterMutex(); + if( pFile->pInode ){ + unixInodeInfo *pInode = pFile->pInode; + sqlite3_mutex_enter(pInode->pLockMutex); + if( pInode->nLock ){ + /* If there are outstanding locks, do not actually close the file just + ** yet because that would clear those locks. Instead, add the file + ** descriptor to pInode->aPending. It will be automatically closed when + ** the last lock is cleared. + */ + setPendingFd(pFile); + } + sqlite3_mutex_leave(pInode->pLockMutex); + } + releaseInodeInfo(pFile); + sqlite3_free(pFile->lockingContext); + rc = closeUnixFile(id); + unixLeaveMutex(); + return rc; +} + +#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ +/* +** The code above is the AFP lock implementation. The code is specific +** to MacOSX and does not work on other unix platforms. No alternative +** is available. If you don't compile for a mac, then the "unix-afp" +** VFS is not available. +** +********************* End of the AFP lock implementation ********************** +******************************************************************************/ + +/****************************************************************************** +*************************** Begin NFS Locking ********************************/ + +#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE +/* + ** Lower the locking level on file descriptor pFile to eFileLock. eFileLock + ** must be either NO_LOCK or SHARED_LOCK. + ** + ** If the locking level of the file descriptor is already at or below + ** the requested locking level, this routine is a no-op. + */ +static int nfsUnlock(sqlite3_file *id, int eFileLock){ + return posixUnlock(id, eFileLock, 1); +} + +#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ +/* +** The code above is the NFS lock implementation. The code is specific +** to MacOSX and does not work on other unix platforms. No alternative +** is available. +** +********************* End of the NFS lock implementation ********************** +******************************************************************************/ + +/****************************************************************************** +**************** Non-locking sqlite3_file methods ***************************** +** +** The next division contains implementations for all methods of the +** sqlite3_file object other than the locking methods. The locking +** methods were defined in divisions above (one locking method per +** division). Those methods that are common to all locking modes +** are gather together into this division. +*/ + +/* +** Seek to the offset passed as the second argument, then read cnt +** bytes into pBuf. Return the number of bytes actually read. +** +** NB: If you define USE_PREAD or USE_PREAD64, then it might also +** be necessary to define _XOPEN_SOURCE to be 500. This varies from +** one system to another. Since SQLite does not define USE_PREAD +** in any form by default, we will not attempt to define _XOPEN_SOURCE. +** See tickets #2741 and #2681. +** +** To avoid stomping the errno value on a failed read the lastErrno value +** is set before returning. +*/ +static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){ + int got; + int prior = 0; +#if (!defined(USE_PREAD) && !defined(USE_PREAD64)) + i64 newOffset; +#endif + TIMER_START; + assert( cnt==(cnt&0x1ffff) ); + assert( id->h>2 ); + do{ +#if defined(USE_PREAD) + got = osPread(id->h, pBuf, cnt, offset); + SimulateIOError( got = -1 ); +#elif defined(USE_PREAD64) + got = osPread64(id->h, pBuf, cnt, offset); + SimulateIOError( got = -1 ); +#else + newOffset = lseek(id->h, offset, SEEK_SET); + SimulateIOError( newOffset = -1 ); + if( newOffset<0 ){ + storeLastErrno((unixFile*)id, errno); + return -1; + } + got = osRead(id->h, pBuf, cnt); +#endif + if( got==cnt ) break; + if( got<0 ){ + if( errno==EINTR ){ got = 1; continue; } + prior = 0; + storeLastErrno((unixFile*)id, errno); + break; + }else if( got>0 ){ + cnt -= got; + offset += got; + prior += got; + pBuf = (void*)(got + (char*)pBuf); + } + }while( got>0 ); + TIMER_END; + OSTRACE(("READ %-3d %5d %7lld %llu\n", + id->h, got+prior, offset-prior, TIMER_ELAPSED)); + return got+prior; +} + +/* +** Read data from a file into a buffer. Return SQLITE_OK if all +** bytes were read successfully and SQLITE_IOERR if anything goes +** wrong. +*/ +static int unixRead( + sqlite3_file *id, + void *pBuf, + int amt, + sqlite3_int64 offset +){ + unixFile *pFile = (unixFile *)id; + int got; + assert( id ); + assert( offset>=0 ); + assert( amt>0 ); + + /* If this is a database file (not a journal, super-journal or temp + ** file), the bytes in the locking range should never be read or written. */ +#if 0 + assert( pFile->pPreallocatedUnused==0 + || offset>=PENDING_BYTE+512 + || offset+amt<=PENDING_BYTE + ); +#endif + +#if SQLITE_MAX_MMAP_SIZE>0 + /* Deal with as much of this read request as possible by transfering + ** data from the memory mapping using memcpy(). */ + if( offset<pFile->mmapSize ){ + if( offset+amt <= pFile->mmapSize ){ + memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt); + return SQLITE_OK; + }else{ + int nCopy = pFile->mmapSize - offset; + memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], nCopy); + pBuf = &((u8 *)pBuf)[nCopy]; + amt -= nCopy; + offset += nCopy; + } + } +#endif + + got = seekAndRead(pFile, offset, pBuf, amt); + if( got==amt ){ + return SQLITE_OK; + }else if( got<0 ){ + /* pFile->lastErrno has been set by seekAndRead(). + ** Usually we return SQLITE_IOERR_READ here, though for some + ** kinds of errors we return SQLITE_IOERR_CORRUPTFS. The + ** SQLITE_IOERR_CORRUPTFS will be converted into SQLITE_CORRUPT + ** prior to returning to the application by the sqlite3ApiExit() + ** routine. + */ + switch( pFile->lastErrno ){ + case ERANGE: + case EIO: +#ifdef ENXIO + case ENXIO: +#endif +#ifdef EDEVERR + case EDEVERR: +#endif + return SQLITE_IOERR_CORRUPTFS; + } + return SQLITE_IOERR_READ; + }else{ + storeLastErrno(pFile, 0); /* not a system error */ + /* Unread parts of the buffer must be zero-filled */ + memset(&((char*)pBuf)[got], 0, amt-got); + return SQLITE_IOERR_SHORT_READ; + } +} + +/* +** Attempt to seek the file-descriptor passed as the first argument to +** absolute offset iOff, then attempt to write nBuf bytes of data from +** pBuf to it. If an error occurs, return -1 and set *piErrno. Otherwise, +** return the actual number of bytes written (which may be less than +** nBuf). +*/ +static int seekAndWriteFd( + int fd, /* File descriptor to write to */ + i64 iOff, /* File offset to begin writing at */ + const void *pBuf, /* Copy data from this buffer to the file */ + int nBuf, /* Size of buffer pBuf in bytes */ + int *piErrno /* OUT: Error number if error occurs */ +){ + int rc = 0; /* Value returned by system call */ + + assert( nBuf==(nBuf&0x1ffff) ); + assert( fd>2 ); + assert( piErrno!=0 ); + nBuf &= 0x1ffff; + TIMER_START; + +#if defined(USE_PREAD) + do{ rc = (int)osPwrite(fd, pBuf, nBuf, iOff); }while( rc<0 && errno==EINTR ); +#elif defined(USE_PREAD64) + do{ rc = (int)osPwrite64(fd, pBuf, nBuf, iOff);}while( rc<0 && errno==EINTR); +#else + do{ + i64 iSeek = lseek(fd, iOff, SEEK_SET); + SimulateIOError( iSeek = -1 ); + if( iSeek<0 ){ + rc = -1; + break; + } + rc = osWrite(fd, pBuf, nBuf); + }while( rc<0 && errno==EINTR ); +#endif + + TIMER_END; + OSTRACE(("WRITE %-3d %5d %7lld %llu\n", fd, rc, iOff, TIMER_ELAPSED)); + + if( rc<0 ) *piErrno = errno; + return rc; +} + + +/* +** Seek to the offset in id->offset then read cnt bytes into pBuf. +** Return the number of bytes actually read. Update the offset. +** +** To avoid stomping the errno value on a failed write the lastErrno value +** is set before returning. +*/ +static int seekAndWrite(unixFile *id, i64 offset, const void *pBuf, int cnt){ + return seekAndWriteFd(id->h, offset, pBuf, cnt, &id->lastErrno); +} + + +/* +** Write data from a buffer into a file. Return SQLITE_OK on success +** or some other error code on failure. +*/ +static int unixWrite( + sqlite3_file *id, + const void *pBuf, + int amt, + sqlite3_int64 offset +){ + unixFile *pFile = (unixFile*)id; + int wrote = 0; + assert( id ); + assert( amt>0 ); + + /* If this is a database file (not a journal, super-journal or temp + ** file), the bytes in the locking range should never be read or written. */ +#if 0 + assert( pFile->pPreallocatedUnused==0 + || offset>=PENDING_BYTE+512 + || offset+amt<=PENDING_BYTE + ); +#endif + +#ifdef SQLITE_DEBUG + /* If we are doing a normal write to a database file (as opposed to + ** doing a hot-journal rollback or a write to some file other than a + ** normal database file) then record the fact that the database + ** has changed. If the transaction counter is modified, record that + ** fact too. + */ + if( pFile->inNormalWrite ){ + pFile->dbUpdate = 1; /* The database has been modified */ + if( offset<=24 && offset+amt>=27 ){ + int rc; + char oldCntr[4]; + SimulateIOErrorBenign(1); + rc = seekAndRead(pFile, 24, oldCntr, 4); + SimulateIOErrorBenign(0); + if( rc!=4 || memcmp(oldCntr, &((char*)pBuf)[24-offset], 4)!=0 ){ + pFile->transCntrChng = 1; /* The transaction counter has changed */ + } + } + } +#endif + +#if defined(SQLITE_MMAP_READWRITE) && SQLITE_MAX_MMAP_SIZE>0 + /* Deal with as much of this write request as possible by transfering + ** data from the memory mapping using memcpy(). */ + if( offset<pFile->mmapSize ){ + if( offset+amt <= pFile->mmapSize ){ + memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt); + return SQLITE_OK; + }else{ + int nCopy = pFile->mmapSize - offset; + memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, nCopy); + pBuf = &((u8 *)pBuf)[nCopy]; + amt -= nCopy; + offset += nCopy; + } + } +#endif + + while( (wrote = seekAndWrite(pFile, offset, pBuf, amt))<amt && wrote>0 ){ + amt -= wrote; + offset += wrote; + pBuf = &((char*)pBuf)[wrote]; + } + SimulateIOError(( wrote=(-1), amt=1 )); + SimulateDiskfullError(( wrote=0, amt=1 )); + + if( amt>wrote ){ + if( wrote<0 && pFile->lastErrno!=ENOSPC ){ + /* lastErrno set by seekAndWrite */ + return SQLITE_IOERR_WRITE; + }else{ + storeLastErrno(pFile, 0); /* not a system error */ + return SQLITE_FULL; + } + } + + return SQLITE_OK; +} + +#ifdef SQLITE_TEST +/* +** Count the number of fullsyncs and normal syncs. This is used to test +** that syncs and fullsyncs are occurring at the right times. +*/ +int sqlite3_sync_count = 0; +int sqlite3_fullsync_count = 0; +#endif + +/* +** We do not trust systems to provide a working fdatasync(). Some do. +** Others do no. To be safe, we will stick with the (slightly slower) +** fsync(). If you know that your system does support fdatasync() correctly, +** then simply compile with -Dfdatasync=fdatasync or -DHAVE_FDATASYNC +*/ +#if !defined(fdatasync) && !HAVE_FDATASYNC +# define fdatasync fsync +#endif + +/* +** Define HAVE_FULLFSYNC to 0 or 1 depending on whether or not +** the F_FULLFSYNC macro is defined. F_FULLFSYNC is currently +** only available on Mac OS X. But that could change. +*/ +#ifdef F_FULLFSYNC +# define HAVE_FULLFSYNC 1 +#else +# define HAVE_FULLFSYNC 0 +#endif + + +/* +** The fsync() system call does not work as advertised on many +** unix systems. The following procedure is an attempt to make +** it work better. +** +** The SQLITE_NO_SYNC macro disables all fsync()s. This is useful +** for testing when we want to run through the test suite quickly. +** You are strongly advised *not* to deploy with SQLITE_NO_SYNC +** enabled, however, since with SQLITE_NO_SYNC enabled, an OS crash +** or power failure will likely corrupt the database file. +** +** SQLite sets the dataOnly flag if the size of the file is unchanged. +** The idea behind dataOnly is that it should only write the file content +** to disk, not the inode. We only set dataOnly if the file size is +** unchanged since the file size is part of the inode. However, +** Ted Ts'o tells us that fdatasync() will also write the inode if the +** file size has changed. The only real difference between fdatasync() +** and fsync(), Ted tells us, is that fdatasync() will not flush the +** inode if the mtime or owner or other inode attributes have changed. +** We only care about the file size, not the other file attributes, so +** as far as SQLite is concerned, an fdatasync() is always adequate. +** So, we always use fdatasync() if it is available, regardless of +** the value of the dataOnly flag. +*/ +static int full_fsync(int fd, int fullSync, int dataOnly){ + int rc; + + /* The following "ifdef/elif/else/" block has the same structure as + ** the one below. It is replicated here solely to avoid cluttering + ** up the real code with the UNUSED_PARAMETER() macros. + */ +#ifdef SQLITE_NO_SYNC + UNUSED_PARAMETER(fd); + UNUSED_PARAMETER(fullSync); + UNUSED_PARAMETER(dataOnly); +#elif HAVE_FULLFSYNC + UNUSED_PARAMETER(dataOnly); +#else + UNUSED_PARAMETER(fullSync); + UNUSED_PARAMETER(dataOnly); +#endif + + /* Record the number of times that we do a normal fsync() and + ** FULLSYNC. This is used during testing to verify that this procedure + ** gets called with the correct arguments. + */ +#ifdef SQLITE_TEST + if( fullSync ) sqlite3_fullsync_count++; + sqlite3_sync_count++; +#endif + + /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a + ** no-op. But go ahead and call fstat() to validate the file + ** descriptor as we need a method to provoke a failure during + ** coverate testing. + */ +#ifdef SQLITE_NO_SYNC + { + struct stat buf; + rc = osFstat(fd, &buf); + } +#elif HAVE_FULLFSYNC + if( fullSync ){ + rc = osFcntl(fd, F_FULLFSYNC, 0); + }else{ + rc = 1; + } + /* If the FULLFSYNC failed, fall back to attempting an fsync(). + ** It shouldn't be possible for fullfsync to fail on the local + ** file system (on OSX), so failure indicates that FULLFSYNC + ** isn't supported for this file system. So, attempt an fsync + ** and (for now) ignore the overhead of a superfluous fcntl call. + ** It'd be better to detect fullfsync support once and avoid + ** the fcntl call every time sync is called. + */ + if( rc ) rc = fsync(fd); + +#elif defined(__APPLE__) + /* fdatasync() on HFS+ doesn't yet flush the file size if it changed correctly + ** so currently we default to the macro that redefines fdatasync to fsync + */ + rc = fsync(fd); +#else + rc = fdatasync(fd); +#if OS_VXWORKS + if( rc==-1 && errno==ENOTSUP ){ + rc = fsync(fd); + } +#endif /* OS_VXWORKS */ +#endif /* ifdef SQLITE_NO_SYNC elif HAVE_FULLFSYNC */ + + if( OS_VXWORKS && rc!= -1 ){ + rc = 0; + } + return rc; +} + +/* +** Open a file descriptor to the directory containing file zFilename. +** If successful, *pFd is set to the opened file descriptor and +** SQLITE_OK is returned. If an error occurs, either SQLITE_NOMEM +** or SQLITE_CANTOPEN is returned and *pFd is set to an undefined +** value. +** +** The directory file descriptor is used for only one thing - to +** fsync() a directory to make sure file creation and deletion events +** are flushed to disk. Such fsyncs are not needed on newer +** journaling filesystems, but are required on older filesystems. +** +** This routine can be overridden using the xSetSysCall interface. +** The ability to override this routine was added in support of the +** chromium sandbox. Opening a directory is a security risk (we are +** told) so making it overrideable allows the chromium sandbox to +** replace this routine with a harmless no-op. To make this routine +** a no-op, replace it with a stub that returns SQLITE_OK but leaves +** *pFd set to a negative number. +** +** If SQLITE_OK is returned, the caller is responsible for closing +** the file descriptor *pFd using close(). +*/ +static int openDirectory(const char *zFilename, int *pFd){ + int ii; + int fd = -1; + char zDirname[MAX_PATHNAME+1]; + + sqlite3_snprintf(MAX_PATHNAME, zDirname, "%s", zFilename); + for(ii=(int)strlen(zDirname); ii>0 && zDirname[ii]!='/'; ii--); + if( ii>0 ){ + zDirname[ii] = '\0'; + }else{ + if( zDirname[0]!='/' ) zDirname[0] = '.'; + zDirname[1] = 0; + } + fd = robust_open(zDirname, O_RDONLY|O_BINARY, 0); + if( fd>=0 ){ + OSTRACE(("OPENDIR %-3d %s\n", fd, zDirname)); + } + *pFd = fd; + if( fd>=0 ) return SQLITE_OK; + return unixLogError(SQLITE_CANTOPEN_BKPT, "openDirectory", zDirname); +} + +/* +** Make sure all writes to a particular file are committed to disk. +** +** If dataOnly==0 then both the file itself and its metadata (file +** size, access time, etc) are synced. If dataOnly!=0 then only the +** file data is synced. +** +** Under Unix, also make sure that the directory entry for the file +** has been created by fsync-ing the directory that contains the file. +** If we do not do this and we encounter a power failure, the directory +** entry for the journal might not exist after we reboot. The next +** SQLite to access the file will not know that the journal exists (because +** the directory entry for the journal was never created) and the transaction +** will not roll back - possibly leading to database corruption. +*/ +static int unixSync(sqlite3_file *id, int flags){ + int rc; + unixFile *pFile = (unixFile*)id; + + int isDataOnly = (flags&SQLITE_SYNC_DATAONLY); + int isFullsync = (flags&0x0F)==SQLITE_SYNC_FULL; + + /* Check that one of SQLITE_SYNC_NORMAL or FULL was passed */ + assert((flags&0x0F)==SQLITE_SYNC_NORMAL + || (flags&0x0F)==SQLITE_SYNC_FULL + ); + + /* Unix cannot, but some systems may return SQLITE_FULL from here. This + ** line is to test that doing so does not cause any problems. + */ + SimulateDiskfullError( return SQLITE_FULL ); + + assert( pFile ); + OSTRACE(("SYNC %-3d\n", pFile->h)); + rc = full_fsync(pFile->h, isFullsync, isDataOnly); + SimulateIOError( rc=1 ); + if( rc ){ + storeLastErrno(pFile, errno); + return unixLogError(SQLITE_IOERR_FSYNC, "full_fsync", pFile->zPath); + } + + /* Also fsync the directory containing the file if the DIRSYNC flag + ** is set. This is a one-time occurrence. Many systems (examples: AIX) + ** are unable to fsync a directory, so ignore errors on the fsync. + */ + if( pFile->ctrlFlags & UNIXFILE_DIRSYNC ){ + int dirfd; + OSTRACE(("DIRSYNC %s (have_fullfsync=%d fullsync=%d)\n", pFile->zPath, + HAVE_FULLFSYNC, isFullsync)); + rc = osOpenDirectory(pFile->zPath, &dirfd); + if( rc==SQLITE_OK ){ + full_fsync(dirfd, 0, 0); + robust_close(pFile, dirfd, __LINE__); + }else{ + assert( rc==SQLITE_CANTOPEN ); + rc = SQLITE_OK; + } + pFile->ctrlFlags &= ~UNIXFILE_DIRSYNC; + } + return rc; +} + +/* +** Truncate an open file to a specified size +*/ +static int unixTruncate(sqlite3_file *id, i64 nByte){ + unixFile *pFile = (unixFile *)id; + int rc; + assert( pFile ); + SimulateIOError( return SQLITE_IOERR_TRUNCATE ); + + /* If the user has configured a chunk-size for this file, truncate the + ** file so that it consists of an integer number of chunks (i.e. the + ** actual file size after the operation may be larger than the requested + ** size). + */ + if( pFile->szChunk>0 ){ + nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk; + } + + rc = robust_ftruncate(pFile->h, nByte); + if( rc ){ + storeLastErrno(pFile, errno); + return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath); + }else{ +#ifdef SQLITE_DEBUG + /* If we are doing a normal write to a database file (as opposed to + ** doing a hot-journal rollback or a write to some file other than a + ** normal database file) and we truncate the file to zero length, + ** that effectively updates the change counter. This might happen + ** when restoring a database using the backup API from a zero-length + ** source. + */ + if( pFile->inNormalWrite && nByte==0 ){ + pFile->transCntrChng = 1; + } +#endif + +#if SQLITE_MAX_MMAP_SIZE>0 + /* If the file was just truncated to a size smaller than the currently + ** mapped region, reduce the effective mapping size as well. SQLite will + ** use read() and write() to access data beyond this point from now on. + */ + if( nByte<pFile->mmapSize ){ + pFile->mmapSize = nByte; + } +#endif + + return SQLITE_OK; + } +} + +/* +** Determine the current size of a file in bytes +*/ +static int unixFileSize(sqlite3_file *id, i64 *pSize){ + int rc; + struct stat buf; + assert( id ); + rc = osFstat(((unixFile*)id)->h, &buf); + SimulateIOError( rc=1 ); + if( rc!=0 ){ + storeLastErrno((unixFile*)id, errno); + return SQLITE_IOERR_FSTAT; + } + *pSize = buf.st_size; + + /* When opening a zero-size database, the findInodeInfo() procedure + ** writes a single byte into that file in order to work around a bug + ** in the OS-X msdos filesystem. In order to avoid problems with upper + ** layers, we need to report this file size as zero even though it is + ** really 1. Ticket #3260. + */ + if( *pSize==1 ) *pSize = 0; + + + return SQLITE_OK; +} + +#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) +/* +** Handler for proxy-locking file-control verbs. Defined below in the +** proxying locking division. +*/ +static int proxyFileControl(sqlite3_file*,int,void*); +#endif + +/* +** This function is called to handle the SQLITE_FCNTL_SIZE_HINT +** file-control operation. Enlarge the database to nBytes in size +** (rounded up to the next chunk-size). If the database is already +** nBytes or larger, this routine is a no-op. +*/ +static int fcntlSizeHint(unixFile *pFile, i64 nByte){ + if( pFile->szChunk>0 ){ + i64 nSize; /* Required file size */ + struct stat buf; /* Used to hold return values of fstat() */ + + if( osFstat(pFile->h, &buf) ){ + return SQLITE_IOERR_FSTAT; + } + + nSize = ((nByte+pFile->szChunk-1) / pFile->szChunk) * pFile->szChunk; + if( nSize>(i64)buf.st_size ){ + +#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE + /* The code below is handling the return value of osFallocate() + ** correctly. posix_fallocate() is defined to "returns zero on success, + ** or an error number on failure". See the manpage for details. */ + int err; + do{ + err = osFallocate(pFile->h, buf.st_size, nSize-buf.st_size); + }while( err==EINTR ); + if( err && err!=EINVAL ) return SQLITE_IOERR_WRITE; +#else + /* If the OS does not have posix_fallocate(), fake it. Write a + ** single byte to the last byte in each block that falls entirely + ** within the extended region. Then, if required, a single byte + ** at offset (nSize-1), to set the size of the file correctly. + ** This is a similar technique to that used by glibc on systems + ** that do not have a real fallocate() call. + */ + int nBlk = buf.st_blksize; /* File-system block size */ + int nWrite = 0; /* Number of bytes written by seekAndWrite */ + i64 iWrite; /* Next offset to write to */ + + iWrite = (buf.st_size/nBlk)*nBlk + nBlk - 1; + assert( iWrite>=buf.st_size ); + assert( ((iWrite+1)%nBlk)==0 ); + for(/*no-op*/; iWrite<nSize+nBlk-1; iWrite+=nBlk ){ + if( iWrite>=nSize ) iWrite = nSize - 1; + nWrite = seekAndWrite(pFile, iWrite, "", 1); + if( nWrite!=1 ) return SQLITE_IOERR_WRITE; + } +#endif + } + } + +#if SQLITE_MAX_MMAP_SIZE>0 + if( pFile->mmapSizeMax>0 && nByte>pFile->mmapSize ){ + int rc; + if( pFile->szChunk<=0 ){ + if( robust_ftruncate(pFile->h, nByte) ){ + storeLastErrno(pFile, errno); + return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath); + } + } + + rc = unixMapfile(pFile, nByte); + return rc; + } +#endif + + return SQLITE_OK; +} + +/* +** If *pArg is initially negative then this is a query. Set *pArg to +** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set. +** +** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags. +*/ +static void unixModeBit(unixFile *pFile, unsigned char mask, int *pArg){ + if( *pArg<0 ){ + *pArg = (pFile->ctrlFlags & mask)!=0; + }else if( (*pArg)==0 ){ + pFile->ctrlFlags &= ~mask; + }else{ + pFile->ctrlFlags |= mask; + } +} + +/* Forward declaration */ +static int unixGetTempname(int nBuf, char *zBuf); +#ifndef SQLITE_OMIT_WAL + static int unixFcntlExternalReader(unixFile*, int*); +#endif + +/* +** Information and control of an open file handle. +*/ +static int unixFileControl(sqlite3_file *id, int op, void *pArg){ + unixFile *pFile = (unixFile*)id; + switch( op ){ +#if defined(__linux__) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE) + case SQLITE_FCNTL_BEGIN_ATOMIC_WRITE: { + int rc = osIoctl(pFile->h, F2FS_IOC_START_ATOMIC_WRITE); + return rc ? SQLITE_IOERR_BEGIN_ATOMIC : SQLITE_OK; + } + case SQLITE_FCNTL_COMMIT_ATOMIC_WRITE: { + int rc = osIoctl(pFile->h, F2FS_IOC_COMMIT_ATOMIC_WRITE); + return rc ? SQLITE_IOERR_COMMIT_ATOMIC : SQLITE_OK; + } + case SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE: { + int rc = osIoctl(pFile->h, F2FS_IOC_ABORT_VOLATILE_WRITE); + return rc ? SQLITE_IOERR_ROLLBACK_ATOMIC : SQLITE_OK; + } +#endif /* __linux__ && SQLITE_ENABLE_BATCH_ATOMIC_WRITE */ + + case SQLITE_FCNTL_LOCKSTATE: { + *(int*)pArg = pFile->eFileLock; + return SQLITE_OK; + } + case SQLITE_FCNTL_LAST_ERRNO: { + *(int*)pArg = pFile->lastErrno; + return SQLITE_OK; + } + case SQLITE_FCNTL_CHUNK_SIZE: { + pFile->szChunk = *(int *)pArg; + return SQLITE_OK; + } + case SQLITE_FCNTL_SIZE_HINT: { + int rc; + SimulateIOErrorBenign(1); + rc = fcntlSizeHint(pFile, *(i64 *)pArg); + SimulateIOErrorBenign(0); + return rc; + } + case SQLITE_FCNTL_PERSIST_WAL: { + unixModeBit(pFile, UNIXFILE_PERSIST_WAL, (int*)pArg); + return SQLITE_OK; + } + case SQLITE_FCNTL_POWERSAFE_OVERWRITE: { + unixModeBit(pFile, UNIXFILE_PSOW, (int*)pArg); + return SQLITE_OK; + } + case SQLITE_FCNTL_VFSNAME: { + *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName); + return SQLITE_OK; + } + case SQLITE_FCNTL_TEMPFILENAME: { + char *zTFile = sqlite3_malloc64( pFile->pVfs->mxPathname ); + if( zTFile ){ + unixGetTempname(pFile->pVfs->mxPathname, zTFile); + *(char**)pArg = zTFile; + } + return SQLITE_OK; + } + case SQLITE_FCNTL_HAS_MOVED: { + *(int*)pArg = fileHasMoved(pFile); + return SQLITE_OK; + } +#ifdef SQLITE_ENABLE_SETLK_TIMEOUT + case SQLITE_FCNTL_LOCK_TIMEOUT: { + int iOld = pFile->iBusyTimeout; + pFile->iBusyTimeout = *(int*)pArg; + *(int*)pArg = iOld; + return SQLITE_OK; + } +#endif +#if SQLITE_MAX_MMAP_SIZE>0 + case SQLITE_FCNTL_MMAP_SIZE: { + i64 newLimit = *(i64*)pArg; + int rc = SQLITE_OK; + if( newLimit>sqlite3GlobalConfig.mxMmap ){ + newLimit = sqlite3GlobalConfig.mxMmap; + } + + /* The value of newLimit may be eventually cast to (size_t) and passed + ** to mmap(). Restrict its value to 2GB if (size_t) is not at least a + ** 64-bit type. */ + if( newLimit>0 && sizeof(size_t)<8 ){ + newLimit = (newLimit & 0x7FFFFFFF); + } + + *(i64*)pArg = pFile->mmapSizeMax; + if( newLimit>=0 && newLimit!=pFile->mmapSizeMax && pFile->nFetchOut==0 ){ + pFile->mmapSizeMax = newLimit; + if( pFile->mmapSize>0 ){ + unixUnmapfile(pFile); + rc = unixMapfile(pFile, -1); + } + } + return rc; + } +#endif +#ifdef SQLITE_DEBUG + /* The pager calls this method to signal that it has done + ** a rollback and that the database is therefore unchanged and + ** it hence it is OK for the transaction change counter to be + ** unchanged. + */ + case SQLITE_FCNTL_DB_UNCHANGED: { + ((unixFile*)id)->dbUpdate = 0; + return SQLITE_OK; + } +#endif +#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) + case SQLITE_FCNTL_SET_LOCKPROXYFILE: + case SQLITE_FCNTL_GET_LOCKPROXYFILE: { + return proxyFileControl(id,op,pArg); + } +#endif /* SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) */ + + case SQLITE_FCNTL_EXTERNAL_READER: { +#ifndef SQLITE_OMIT_WAL + return unixFcntlExternalReader((unixFile*)id, (int*)pArg); +#else + *(int*)pArg = 0; + return SQLITE_OK; +#endif + } + } + return SQLITE_NOTFOUND; +} + +/* +** If pFd->sectorSize is non-zero when this function is called, it is a +** no-op. Otherwise, the values of pFd->sectorSize and +** pFd->deviceCharacteristics are set according to the file-system +** characteristics. +** +** There are two versions of this function. One for QNX and one for all +** other systems. +*/ +#ifndef __QNXNTO__ +static void setDeviceCharacteristics(unixFile *pFd){ + assert( pFd->deviceCharacteristics==0 || pFd->sectorSize!=0 ); + if( pFd->sectorSize==0 ){ +#if defined(__linux__) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE) + int res; + u32 f = 0; + + /* Check for support for F2FS atomic batch writes. */ + res = osIoctl(pFd->h, F2FS_IOC_GET_FEATURES, &f); + if( res==0 && (f & F2FS_FEATURE_ATOMIC_WRITE) ){ + pFd->deviceCharacteristics = SQLITE_IOCAP_BATCH_ATOMIC; + } +#endif /* __linux__ && SQLITE_ENABLE_BATCH_ATOMIC_WRITE */ + + /* Set the POWERSAFE_OVERWRITE flag if requested. */ + if( pFd->ctrlFlags & UNIXFILE_PSOW ){ + pFd->deviceCharacteristics |= SQLITE_IOCAP_POWERSAFE_OVERWRITE; + } + + pFd->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE; + } +} +#else +#include <sys/dcmd_blk.h> +#include <sys/statvfs.h> +static void setDeviceCharacteristics(unixFile *pFile){ + if( pFile->sectorSize == 0 ){ + struct statvfs fsInfo; + + /* Set defaults for non-supported filesystems */ + pFile->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE; + pFile->deviceCharacteristics = 0; + if( fstatvfs(pFile->h, &fsInfo) == -1 ) { + return; + } + + if( !strcmp(fsInfo.f_basetype, "tmp") ) { + pFile->sectorSize = fsInfo.f_bsize; + pFile->deviceCharacteristics = + SQLITE_IOCAP_ATOMIC4K | /* All ram filesystem writes are atomic */ + SQLITE_IOCAP_SAFE_APPEND | /* growing the file does not occur until + ** the write succeeds */ + SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind + ** so it is ordered */ + 0; + }else if( strstr(fsInfo.f_basetype, "etfs") ){ + pFile->sectorSize = fsInfo.f_bsize; + pFile->deviceCharacteristics = + /* etfs cluster size writes are atomic */ + (pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) | + SQLITE_IOCAP_SAFE_APPEND | /* growing the file does not occur until + ** the write succeeds */ + SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind + ** so it is ordered */ + 0; + }else if( !strcmp(fsInfo.f_basetype, "qnx6") ){ + pFile->sectorSize = fsInfo.f_bsize; + pFile->deviceCharacteristics = + SQLITE_IOCAP_ATOMIC | /* All filesystem writes are atomic */ + SQLITE_IOCAP_SAFE_APPEND | /* growing the file does not occur until + ** the write succeeds */ + SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind + ** so it is ordered */ + 0; + }else if( !strcmp(fsInfo.f_basetype, "qnx4") ){ + pFile->sectorSize = fsInfo.f_bsize; + pFile->deviceCharacteristics = + /* full bitset of atomics from max sector size and smaller */ + ((pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) << 1) - 2 | + SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind + ** so it is ordered */ + 0; + }else if( strstr(fsInfo.f_basetype, "dos") ){ + pFile->sectorSize = fsInfo.f_bsize; + pFile->deviceCharacteristics = + /* full bitset of atomics from max sector size and smaller */ + ((pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) << 1) - 2 | + SQLITE_IOCAP_SEQUENTIAL | /* The ram filesystem has no write behind + ** so it is ordered */ + 0; + }else{ + pFile->deviceCharacteristics = + SQLITE_IOCAP_ATOMIC512 | /* blocks are atomic */ + SQLITE_IOCAP_SAFE_APPEND | /* growing the file does not occur until + ** the write succeeds */ + 0; + } + } + /* Last chance verification. If the sector size isn't a multiple of 512 + ** then it isn't valid.*/ + if( pFile->sectorSize % 512 != 0 ){ + pFile->deviceCharacteristics = 0; + pFile->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE; + } +} +#endif + +/* +** Return the sector size in bytes of the underlying block device for +** the specified file. This is almost always 512 bytes, but may be +** larger for some devices. +** +** SQLite code assumes this function cannot fail. It also assumes that +** if two files are created in the same file-system directory (i.e. +** a database and its journal file) that the sector size will be the +** same for both. +*/ +static int unixSectorSize(sqlite3_file *id){ + unixFile *pFd = (unixFile*)id; + setDeviceCharacteristics(pFd); + return pFd->sectorSize; +} + +/* +** Return the device characteristics for the file. +** +** This VFS is set up to return SQLITE_IOCAP_POWERSAFE_OVERWRITE by default. +** However, that choice is controversial since technically the underlying +** file system does not always provide powersafe overwrites. (In other +** words, after a power-loss event, parts of the file that were never +** written might end up being altered.) However, non-PSOW behavior is very, +** very rare. And asserting PSOW makes a large reduction in the amount +** of required I/O for journaling, since a lot of padding is eliminated. +** Hence, while POWERSAFE_OVERWRITE is on by default, there is a file-control +** available to turn it off and URI query parameter available to turn it off. +*/ +static int unixDeviceCharacteristics(sqlite3_file *id){ + unixFile *pFd = (unixFile*)id; + setDeviceCharacteristics(pFd); + return pFd->deviceCharacteristics; +} + +#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 + +/* +** Return the system page size. +** +** This function should not be called directly by other code in this file. +** Instead, it should be called via macro osGetpagesize(). +*/ +static int unixGetpagesize(void){ +#if OS_VXWORKS + return 1024; +#elif defined(_BSD_SOURCE) + return getpagesize(); +#else + return (int)sysconf(_SC_PAGESIZE); +#endif +} + +#endif /* !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 */ + +#ifndef SQLITE_OMIT_WAL + +/* +** Object used to represent an shared memory buffer. +** +** When multiple threads all reference the same wal-index, each thread +** has its own unixShm object, but they all point to a single instance +** of this unixShmNode object. In other words, each wal-index is opened +** only once per process. +** +** Each unixShmNode object is connected to a single unixInodeInfo object. +** We could coalesce this object into unixInodeInfo, but that would mean +** every open file that does not use shared memory (in other words, most +** open files) would have to carry around this extra information. So +** the unixInodeInfo object contains a pointer to this unixShmNode object +** and the unixShmNode object is created only when needed. +** +** unixMutexHeld() must be true when creating or destroying +** this object or while reading or writing the following fields: +** +** nRef +** +** The following fields are read-only after the object is created: +** +** hShm +** zFilename +** +** Either unixShmNode.pShmMutex must be held or unixShmNode.nRef==0 and +** unixMutexHeld() is true when reading or writing any other field +** in this structure. +*/ +struct unixShmNode { + unixInodeInfo *pInode; /* unixInodeInfo that owns this SHM node */ + sqlite3_mutex *pShmMutex; /* Mutex to access this object */ + char *zFilename; /* Name of the mmapped file */ + int hShm; /* Open file descriptor */ + int szRegion; /* Size of shared-memory regions */ + u16 nRegion; /* Size of array apRegion */ + u8 isReadonly; /* True if read-only */ + u8 isUnlocked; /* True if no DMS lock held */ + char **apRegion; /* Array of mapped shared-memory regions */ + int nRef; /* Number of unixShm objects pointing to this */ + unixShm *pFirst; /* All unixShm objects pointing to this */ + int aLock[SQLITE_SHM_NLOCK]; /* # shared locks on slot, -1==excl lock */ +#ifdef SQLITE_DEBUG + u8 exclMask; /* Mask of exclusive locks held */ + u8 sharedMask; /* Mask of shared locks held */ + u8 nextShmId; /* Next available unixShm.id value */ +#endif +}; + +/* +** Structure used internally by this VFS to record the state of an +** open shared memory connection. +** +** The following fields are initialized when this object is created and +** are read-only thereafter: +** +** unixShm.pShmNode +** unixShm.id +** +** All other fields are read/write. The unixShm.pShmNode->pShmMutex must +** be held while accessing any read/write fields. +*/ +struct unixShm { + unixShmNode *pShmNode; /* The underlying unixShmNode object */ + unixShm *pNext; /* Next unixShm with the same unixShmNode */ + u8 hasMutex; /* True if holding the unixShmNode->pShmMutex */ + u8 id; /* Id of this connection within its unixShmNode */ + u16 sharedMask; /* Mask of shared locks held */ + u16 exclMask; /* Mask of exclusive locks held */ +}; + +/* +** Constants used for locking +*/ +#define UNIX_SHM_BASE ((22+SQLITE_SHM_NLOCK)*4) /* first lock byte */ +#define UNIX_SHM_DMS (UNIX_SHM_BASE+SQLITE_SHM_NLOCK) /* deadman switch */ + +/* +** Use F_GETLK to check whether or not there are any readers with open +** wal-mode transactions in other processes on database file pFile. If +** no error occurs, return SQLITE_OK and set (*piOut) to 1 if there are +** such transactions, or 0 otherwise. If an error occurs, return an +** SQLite error code. The final value of *piOut is undefined in this +** case. +*/ +static int unixFcntlExternalReader(unixFile *pFile, int *piOut){ + int rc = SQLITE_OK; + *piOut = 0; + if( pFile->pShm){ + unixShmNode *pShmNode = pFile->pShm->pShmNode; + struct flock f; + + memset(&f, 0, sizeof(f)); + f.l_type = F_WRLCK; + f.l_whence = SEEK_SET; + f.l_start = UNIX_SHM_BASE + 3; + f.l_len = SQLITE_SHM_NLOCK - 3; + + sqlite3_mutex_enter(pShmNode->pShmMutex); + if( osFcntl(pShmNode->hShm, F_GETLK, &f)<0 ){ + rc = SQLITE_IOERR_LOCK; + }else{ + *piOut = (f.l_type!=F_UNLCK); + } + sqlite3_mutex_leave(pShmNode->pShmMutex); + } + + return rc; +} + + +/* +** Apply posix advisory locks for all bytes from ofst through ofst+n-1. +** +** Locks block if the mask is exactly UNIX_SHM_C and are non-blocking +** otherwise. +*/ +static int unixShmSystemLock( + unixFile *pFile, /* Open connection to the WAL file */ + int lockType, /* F_UNLCK, F_RDLCK, or F_WRLCK */ + int ofst, /* First byte of the locking range */ + int n /* Number of bytes to lock */ +){ + unixShmNode *pShmNode; /* Apply locks to this open shared-memory segment */ + struct flock f; /* The posix advisory locking structure */ + int rc = SQLITE_OK; /* Result code form fcntl() */ + + /* Access to the unixShmNode object is serialized by the caller */ + pShmNode = pFile->pInode->pShmNode; + assert( pShmNode->nRef==0 || sqlite3_mutex_held(pShmNode->pShmMutex) ); + assert( pShmNode->nRef>0 || unixMutexHeld() ); + + /* Shared locks never span more than one byte */ + assert( n==1 || lockType!=F_RDLCK ); + + /* Locks are within range */ + assert( n>=1 && n<=SQLITE_SHM_NLOCK ); + + if( pShmNode->hShm>=0 ){ + int res; + /* Initialize the locking parameters */ + f.l_type = lockType; + f.l_whence = SEEK_SET; + f.l_start = ofst; + f.l_len = n; + res = osSetPosixAdvisoryLock(pShmNode->hShm, &f, pFile); + if( res==-1 ){ +#ifdef SQLITE_ENABLE_SETLK_TIMEOUT + rc = (pFile->iBusyTimeout ? SQLITE_BUSY_TIMEOUT : SQLITE_BUSY); +#else + rc = SQLITE_BUSY; +#endif + } + } + + /* Update the global lock state and do debug tracing */ +#ifdef SQLITE_DEBUG + { u16 mask; + OSTRACE(("SHM-LOCK ")); + mask = ofst>31 ? 0xffff : (1<<(ofst+n)) - (1<<ofst); + if( rc==SQLITE_OK ){ + if( lockType==F_UNLCK ){ + OSTRACE(("unlock %d ok", ofst)); + pShmNode->exclMask &= ~mask; + pShmNode->sharedMask &= ~mask; + }else if( lockType==F_RDLCK ){ + OSTRACE(("read-lock %d ok", ofst)); + pShmNode->exclMask &= ~mask; + pShmNode->sharedMask |= mask; + }else{ + assert( lockType==F_WRLCK ); + OSTRACE(("write-lock %d ok", ofst)); + pShmNode->exclMask |= mask; + pShmNode->sharedMask &= ~mask; + } + }else{ + if( lockType==F_UNLCK ){ + OSTRACE(("unlock %d failed", ofst)); + }else if( lockType==F_RDLCK ){ + OSTRACE(("read-lock failed")); + }else{ + assert( lockType==F_WRLCK ); + OSTRACE(("write-lock %d failed", ofst)); + } + } + OSTRACE((" - afterwards %03x,%03x\n", + pShmNode->sharedMask, pShmNode->exclMask)); + } +#endif + + return rc; +} + +/* +** Return the minimum number of 32KB shm regions that should be mapped at +** a time, assuming that each mapping must be an integer multiple of the +** current system page-size. +** +** Usually, this is 1. The exception seems to be systems that are configured +** to use 64KB pages - in this case each mapping must cover at least two +** shm regions. +*/ +static int unixShmRegionPerMap(void){ + int shmsz = 32*1024; /* SHM region size */ + int pgsz = osGetpagesize(); /* System page size */ + assert( ((pgsz-1)&pgsz)==0 ); /* Page size must be a power of 2 */ + if( pgsz<shmsz ) return 1; + return pgsz/shmsz; +} + +/* +** Purge the unixShmNodeList list of all entries with unixShmNode.nRef==0. +** +** This is not a VFS shared-memory method; it is a utility function called +** by VFS shared-memory methods. +*/ +static void unixShmPurge(unixFile *pFd){ + unixShmNode *p = pFd->pInode->pShmNode; + assert( unixMutexHeld() ); + if( p && ALWAYS(p->nRef==0) ){ + int nShmPerMap = unixShmRegionPerMap(); + int i; + assert( p->pInode==pFd->pInode ); + sqlite3_mutex_free(p->pShmMutex); + for(i=0; i<p->nRegion; i+=nShmPerMap){ + if( p->hShm>=0 ){ + osMunmap(p->apRegion[i], p->szRegion); + }else{ + sqlite3_free(p->apRegion[i]); + } + } + sqlite3_free(p->apRegion); + if( p->hShm>=0 ){ + robust_close(pFd, p->hShm, __LINE__); + p->hShm = -1; + } + p->pInode->pShmNode = 0; + sqlite3_free(p); + } +} + +/* +** The DMS lock has not yet been taken on shm file pShmNode. Attempt to +** take it now. Return SQLITE_OK if successful, or an SQLite error +** code otherwise. +** +** If the DMS cannot be locked because this is a readonly_shm=1 +** connection and no other process already holds a lock, return +** SQLITE_READONLY_CANTINIT and set pShmNode->isUnlocked=1. +*/ +static int unixLockSharedMemory(unixFile *pDbFd, unixShmNode *pShmNode){ + struct flock lock; + int rc = SQLITE_OK; + + /* Use F_GETLK to determine the locks other processes are holding + ** on the DMS byte. If it indicates that another process is holding + ** a SHARED lock, then this process may also take a SHARED lock + ** and proceed with opening the *-shm file. + ** + ** Or, if no other process is holding any lock, then this process + ** is the first to open it. In this case take an EXCLUSIVE lock on the + ** DMS byte and truncate the *-shm file to zero bytes in size. Then + ** downgrade to a SHARED lock on the DMS byte. + ** + ** If another process is holding an EXCLUSIVE lock on the DMS byte, + ** return SQLITE_BUSY to the caller (it will try again). An earlier + ** version of this code attempted the SHARED lock at this point. But + ** this introduced a subtle race condition: if the process holding + ** EXCLUSIVE failed just before truncating the *-shm file, then this + ** process might open and use the *-shm file without truncating it. + ** And if the *-shm file has been corrupted by a power failure or + ** system crash, the database itself may also become corrupt. */ + lock.l_whence = SEEK_SET; + lock.l_start = UNIX_SHM_DMS; + lock.l_len = 1; + lock.l_type = F_WRLCK; + if( osFcntl(pShmNode->hShm, F_GETLK, &lock)!=0 ) { + rc = SQLITE_IOERR_LOCK; + }else if( lock.l_type==F_UNLCK ){ + if( pShmNode->isReadonly ){ + pShmNode->isUnlocked = 1; + rc = SQLITE_READONLY_CANTINIT; + }else{ + rc = unixShmSystemLock(pDbFd, F_WRLCK, UNIX_SHM_DMS, 1); + /* The first connection to attach must truncate the -shm file. We + ** truncate to 3 bytes (an arbitrary small number, less than the + ** -shm header size) rather than 0 as a system debugging aid, to + ** help detect if a -shm file truncation is legitimate or is the work + ** or a rogue process. */ + if( rc==SQLITE_OK && robust_ftruncate(pShmNode->hShm, 3) ){ + rc = unixLogError(SQLITE_IOERR_SHMOPEN,"ftruncate",pShmNode->zFilename); + } + } + }else if( lock.l_type==F_WRLCK ){ + rc = SQLITE_BUSY; + } + + if( rc==SQLITE_OK ){ + assert( lock.l_type==F_UNLCK || lock.l_type==F_RDLCK ); + rc = unixShmSystemLock(pDbFd, F_RDLCK, UNIX_SHM_DMS, 1); + } + return rc; +} + +/* +** Open a shared-memory area associated with open database file pDbFd. +** This particular implementation uses mmapped files. +** +** The file used to implement shared-memory is in the same directory +** as the open database file and has the same name as the open database +** file with the "-shm" suffix added. For example, if the database file +** is "/home/user1/config.db" then the file that is created and mmapped +** for shared memory will be called "/home/user1/config.db-shm". +** +** Another approach to is to use files in /dev/shm or /dev/tmp or an +** some other tmpfs mount. But if a file in a different directory +** from the database file is used, then differing access permissions +** or a chroot() might cause two different processes on the same +** database to end up using different files for shared memory - +** meaning that their memory would not really be shared - resulting +** in database corruption. Nevertheless, this tmpfs file usage +** can be enabled at compile-time using -DSQLITE_SHM_DIRECTORY="/dev/shm" +** or the equivalent. The use of the SQLITE_SHM_DIRECTORY compile-time +** option results in an incompatible build of SQLite; builds of SQLite +** that with differing SQLITE_SHM_DIRECTORY settings attempt to use the +** same database file at the same time, database corruption will likely +** result. The SQLITE_SHM_DIRECTORY compile-time option is considered +** "unsupported" and may go away in a future SQLite release. +** +** When opening a new shared-memory file, if no other instances of that +** file are currently open, in this process or in other processes, then +** the file must be truncated to zero length or have its header cleared. +** +** If the original database file (pDbFd) is using the "unix-excl" VFS +** that means that an exclusive lock is held on the database file and +** that no other processes are able to read or write the database. In +** that case, we do not really need shared memory. No shared memory +** file is created. The shared memory will be simulated with heap memory. +*/ +static int unixOpenSharedMemory(unixFile *pDbFd){ + struct unixShm *p = 0; /* The connection to be opened */ + struct unixShmNode *pShmNode; /* The underlying mmapped file */ + int rc = SQLITE_OK; /* Result code */ + unixInodeInfo *pInode; /* The inode of fd */ + char *zShm; /* Name of the file used for SHM */ + int nShmFilename; /* Size of the SHM filename in bytes */ + + /* Allocate space for the new unixShm object. */ + p = sqlite3_malloc64( sizeof(*p) ); + if( p==0 ) return SQLITE_NOMEM_BKPT; + memset(p, 0, sizeof(*p)); + assert( pDbFd->pShm==0 ); + + /* Check to see if a unixShmNode object already exists. Reuse an existing + ** one if present. Create a new one if necessary. + */ + assert( unixFileMutexNotheld(pDbFd) ); + unixEnterMutex(); + pInode = pDbFd->pInode; + pShmNode = pInode->pShmNode; + if( pShmNode==0 ){ + struct stat sStat; /* fstat() info for database file */ +#ifndef SQLITE_SHM_DIRECTORY + const char *zBasePath = pDbFd->zPath; +#endif + + /* Call fstat() to figure out the permissions on the database file. If + ** a new *-shm file is created, an attempt will be made to create it + ** with the same permissions. + */ + if( osFstat(pDbFd->h, &sStat) ){ + rc = SQLITE_IOERR_FSTAT; + goto shm_open_err; + } + +#ifdef SQLITE_SHM_DIRECTORY + nShmFilename = sizeof(SQLITE_SHM_DIRECTORY) + 31; +#else + nShmFilename = 6 + (int)strlen(zBasePath); +#endif + pShmNode = sqlite3_malloc64( sizeof(*pShmNode) + nShmFilename ); + if( pShmNode==0 ){ + rc = SQLITE_NOMEM_BKPT; + goto shm_open_err; + } + memset(pShmNode, 0, sizeof(*pShmNode)+nShmFilename); + zShm = pShmNode->zFilename = (char*)&pShmNode[1]; +#ifdef SQLITE_SHM_DIRECTORY + sqlite3_snprintf(nShmFilename, zShm, + SQLITE_SHM_DIRECTORY "/sqlite-shm-%x-%x", + (u32)sStat.st_ino, (u32)sStat.st_dev); +#else + sqlite3_snprintf(nShmFilename, zShm, "%s-shm", zBasePath); + sqlite3FileSuffix3(pDbFd->zPath, zShm); +#endif + pShmNode->hShm = -1; + pDbFd->pInode->pShmNode = pShmNode; + pShmNode->pInode = pDbFd->pInode; + if( sqlite3GlobalConfig.bCoreMutex ){ + pShmNode->pShmMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST); + if( pShmNode->pShmMutex==0 ){ + rc = SQLITE_NOMEM_BKPT; + goto shm_open_err; + } + } + + if( pInode->bProcessLock==0 ){ + if( 0==sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){ + pShmNode->hShm = robust_open(zShm, O_RDWR|O_CREAT|O_NOFOLLOW, + (sStat.st_mode&0777)); + } + if( pShmNode->hShm<0 ){ + pShmNode->hShm = robust_open(zShm, O_RDONLY|O_NOFOLLOW, + (sStat.st_mode&0777)); + if( pShmNode->hShm<0 ){ + rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShm); + goto shm_open_err; + } + pShmNode->isReadonly = 1; + } + + /* If this process is running as root, make sure that the SHM file + ** is owned by the same user that owns the original database. Otherwise, + ** the original owner will not be able to connect. + */ + robustFchown(pShmNode->hShm, sStat.st_uid, sStat.st_gid); + + rc = unixLockSharedMemory(pDbFd, pShmNode); + if( rc!=SQLITE_OK && rc!=SQLITE_READONLY_CANTINIT ) goto shm_open_err; + } + } + + /* Make the new connection a child of the unixShmNode */ + p->pShmNode = pShmNode; +#ifdef SQLITE_DEBUG + p->id = pShmNode->nextShmId++; +#endif + pShmNode->nRef++; + pDbFd->pShm = p; + unixLeaveMutex(); + + /* The reference count on pShmNode has already been incremented under + ** the cover of the unixEnterMutex() mutex and the pointer from the + ** new (struct unixShm) object to the pShmNode has been set. All that is + ** left to do is to link the new object into the linked list starting + ** at pShmNode->pFirst. This must be done while holding the + ** pShmNode->pShmMutex. + */ + sqlite3_mutex_enter(pShmNode->pShmMutex); + p->pNext = pShmNode->pFirst; + pShmNode->pFirst = p; + sqlite3_mutex_leave(pShmNode->pShmMutex); + return rc; + + /* Jump here on any error */ +shm_open_err: + unixShmPurge(pDbFd); /* This call frees pShmNode if required */ + sqlite3_free(p); + unixLeaveMutex(); + return rc; +} + +/* +** This function is called to obtain a pointer to region iRegion of the +** shared-memory associated with the database file fd. Shared-memory regions +** are numbered starting from zero. Each shared-memory region is szRegion +** bytes in size. +** +** If an error occurs, an error code is returned and *pp is set to NULL. +** +** Otherwise, if the bExtend parameter is 0 and the requested shared-memory +** region has not been allocated (by any client, including one running in a +** separate process), then *pp is set to NULL and SQLITE_OK returned. If +** bExtend is non-zero and the requested shared-memory region has not yet +** been allocated, it is allocated by this function. +** +** If the shared-memory region has already been allocated or is allocated by +** this call as described above, then it is mapped into this processes +** address space (if it is not already), *pp is set to point to the mapped +** memory and SQLITE_OK returned. +*/ +static int unixShmMap( + sqlite3_file *fd, /* Handle open on database file */ + int iRegion, /* Region to retrieve */ + int szRegion, /* Size of regions */ + int bExtend, /* True to extend file if necessary */ + void volatile **pp /* OUT: Mapped memory */ +){ + unixFile *pDbFd = (unixFile*)fd; + unixShm *p; + unixShmNode *pShmNode; + int rc = SQLITE_OK; + int nShmPerMap = unixShmRegionPerMap(); + int nReqRegion; + + /* If the shared-memory file has not yet been opened, open it now. */ + if( pDbFd->pShm==0 ){ + rc = unixOpenSharedMemory(pDbFd); + if( rc!=SQLITE_OK ) return rc; + } + + p = pDbFd->pShm; + pShmNode = p->pShmNode; + sqlite3_mutex_enter(pShmNode->pShmMutex); + if( pShmNode->isUnlocked ){ + rc = unixLockSharedMemory(pDbFd, pShmNode); + if( rc!=SQLITE_OK ) goto shmpage_out; + pShmNode->isUnlocked = 0; + } + assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 ); + assert( pShmNode->pInode==pDbFd->pInode ); + assert( pShmNode->hShm>=0 || pDbFd->pInode->bProcessLock==1 ); + assert( pShmNode->hShm<0 || pDbFd->pInode->bProcessLock==0 ); + + /* Minimum number of regions required to be mapped. */ + nReqRegion = ((iRegion+nShmPerMap) / nShmPerMap) * nShmPerMap; + + if( pShmNode->nRegion<nReqRegion ){ + char **apNew; /* New apRegion[] array */ + int nByte = nReqRegion*szRegion; /* Minimum required file size */ + struct stat sStat; /* Used by fstat() */ + + pShmNode->szRegion = szRegion; + + if( pShmNode->hShm>=0 ){ + /* The requested region is not mapped into this processes address space. + ** Check to see if it has been allocated (i.e. if the wal-index file is + ** large enough to contain the requested region). + */ + if( osFstat(pShmNode->hShm, &sStat) ){ + rc = SQLITE_IOERR_SHMSIZE; + goto shmpage_out; + } + + if( sStat.st_size<nByte ){ + /* The requested memory region does not exist. If bExtend is set to + ** false, exit early. *pp will be set to NULL and SQLITE_OK returned. + */ + if( !bExtend ){ + goto shmpage_out; + } + + /* Alternatively, if bExtend is true, extend the file. Do this by + ** writing a single byte to the end of each (OS) page being + ** allocated or extended. Technically, we need only write to the + ** last page in order to extend the file. But writing to all new + ** pages forces the OS to allocate them immediately, which reduces + ** the chances of SIGBUS while accessing the mapped region later on. + */ + else{ + static const int pgsz = 4096; + int iPg; + + /* Write to the last byte of each newly allocated or extended page */ + assert( (nByte % pgsz)==0 ); + for(iPg=(sStat.st_size/pgsz); iPg<(nByte/pgsz); iPg++){ + int x = 0; + if( seekAndWriteFd(pShmNode->hShm, iPg*pgsz + pgsz-1,"",1,&x)!=1 ){ + const char *zFile = pShmNode->zFilename; + rc = unixLogError(SQLITE_IOERR_SHMSIZE, "write", zFile); + goto shmpage_out; + } + } + } + } + } + + /* Map the requested memory region into this processes address space. */ + apNew = (char **)sqlite3_realloc( + pShmNode->apRegion, nReqRegion*sizeof(char *) + ); + if( !apNew ){ + rc = SQLITE_IOERR_NOMEM_BKPT; + goto shmpage_out; + } + pShmNode->apRegion = apNew; + while( pShmNode->nRegion<nReqRegion ){ + int nMap = szRegion*nShmPerMap; + int i; + void *pMem; + if( pShmNode->hShm>=0 ){ + pMem = osMmap(0, nMap, + pShmNode->isReadonly ? PROT_READ : PROT_READ|PROT_WRITE, + MAP_SHARED, pShmNode->hShm, szRegion*(i64)pShmNode->nRegion + ); + if( pMem==MAP_FAILED ){ + rc = unixLogError(SQLITE_IOERR_SHMMAP, "mmap", pShmNode->zFilename); + goto shmpage_out; + } + }else{ + pMem = sqlite3_malloc64(nMap); + if( pMem==0 ){ + rc = SQLITE_NOMEM_BKPT; + goto shmpage_out; + } + memset(pMem, 0, nMap); + } + + for(i=0; i<nShmPerMap; i++){ + pShmNode->apRegion[pShmNode->nRegion+i] = &((char*)pMem)[szRegion*i]; + } + pShmNode->nRegion += nShmPerMap; + } + } + +shmpage_out: + if( pShmNode->nRegion>iRegion ){ + *pp = pShmNode->apRegion[iRegion]; + }else{ + *pp = 0; + } + if( pShmNode->isReadonly && rc==SQLITE_OK ) rc = SQLITE_READONLY; + sqlite3_mutex_leave(pShmNode->pShmMutex); + return rc; +} + +/* +** Check that the pShmNode->aLock[] array comports with the locking bitmasks +** held by each client. Return true if it does, or false otherwise. This +** is to be used in an assert(). e.g. +** +** assert( assertLockingArrayOk(pShmNode) ); +*/ +#ifdef SQLITE_DEBUG +static int assertLockingArrayOk(unixShmNode *pShmNode){ + unixShm *pX; + int aLock[SQLITE_SHM_NLOCK]; + assert( sqlite3_mutex_held(pShmNode->pShmMutex) ); + + memset(aLock, 0, sizeof(aLock)); + for(pX=pShmNode->pFirst; pX; pX=pX->pNext){ + int i; + for(i=0; i<SQLITE_SHM_NLOCK; i++){ + if( pX->exclMask & (1<<i) ){ + assert( aLock[i]==0 ); + aLock[i] = -1; + }else if( pX->sharedMask & (1<<i) ){ + assert( aLock[i]>=0 ); + aLock[i]++; + } + } + } + + assert( 0==memcmp(pShmNode->aLock, aLock, sizeof(aLock)) ); + return (memcmp(pShmNode->aLock, aLock, sizeof(aLock))==0); +} +#endif + +/* +** Change the lock state for a shared-memory segment. +** +** Note that the relationship between SHAREd and EXCLUSIVE locks is a little +** different here than in posix. In xShmLock(), one can go from unlocked +** to shared and back or from unlocked to exclusive and back. But one may +** not go from shared to exclusive or from exclusive to shared. +*/ +static int unixShmLock( + sqlite3_file *fd, /* Database file holding the shared memory */ + int ofst, /* First lock to acquire or release */ + int n, /* Number of locks to acquire or release */ + int flags /* What to do with the lock */ +){ + unixFile *pDbFd = (unixFile*)fd; /* Connection holding shared memory */ + unixShm *p; /* The shared memory being locked */ + unixShmNode *pShmNode; /* The underlying file iNode */ + int rc = SQLITE_OK; /* Result code */ + u16 mask; /* Mask of locks to take or release */ + int *aLock; + + p = pDbFd->pShm; + if( p==0 ) return SQLITE_IOERR_SHMLOCK; + pShmNode = p->pShmNode; + if( NEVER(pShmNode==0) ) return SQLITE_IOERR_SHMLOCK; + aLock = pShmNode->aLock; + + assert( pShmNode==pDbFd->pInode->pShmNode ); + assert( pShmNode->pInode==pDbFd->pInode ); + assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK ); + assert( n>=1 ); + assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED) + || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE) + || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED) + || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) ); + assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 ); + assert( pShmNode->hShm>=0 || pDbFd->pInode->bProcessLock==1 ); + assert( pShmNode->hShm<0 || pDbFd->pInode->bProcessLock==0 ); + + /* Check that, if this to be a blocking lock, no locks that occur later + ** in the following list than the lock being obtained are already held: + ** + ** 1. Checkpointer lock (ofst==1). + ** 2. Write lock (ofst==0). + ** 3. Read locks (ofst>=3 && ofst<SQLITE_SHM_NLOCK). + ** + ** In other words, if this is a blocking lock, none of the locks that + ** occur later in the above list than the lock being obtained may be + ** held. + ** + ** It is not permitted to block on the RECOVER lock. + */ +#ifdef SQLITE_ENABLE_SETLK_TIMEOUT + assert( (flags & SQLITE_SHM_UNLOCK) || pDbFd->iBusyTimeout==0 || ( + (ofst!=2) /* not RECOVER */ + && (ofst!=1 || (p->exclMask|p->sharedMask)==0) + && (ofst!=0 || (p->exclMask|p->sharedMask)<3) + && (ofst<3 || (p->exclMask|p->sharedMask)<(1<<ofst)) + )); +#endif + + mask = (1<<(ofst+n)) - (1<<ofst); + assert( n>1 || mask==(1<<ofst) ); + sqlite3_mutex_enter(pShmNode->pShmMutex); + assert( assertLockingArrayOk(pShmNode) ); + if( flags & SQLITE_SHM_UNLOCK ){ + if( (p->exclMask|p->sharedMask) & mask ){ + int ii; + int bUnlock = 1; + + for(ii=ofst; ii<ofst+n; ii++){ + if( aLock[ii]>((p->sharedMask & (1<<ii)) ? 1 : 0) ){ + bUnlock = 0; + } + } + + if( bUnlock ){ + rc = unixShmSystemLock(pDbFd, F_UNLCK, ofst+UNIX_SHM_BASE, n); + if( rc==SQLITE_OK ){ + memset(&aLock[ofst], 0, sizeof(int)*n); + } + }else if( ALWAYS(p->sharedMask & (1<<ofst)) ){ + assert( n==1 && aLock[ofst]>1 ); + aLock[ofst]--; + } + + /* Undo the local locks */ + if( rc==SQLITE_OK ){ + p->exclMask &= ~mask; + p->sharedMask &= ~mask; + } + } + }else if( flags & SQLITE_SHM_SHARED ){ + assert( n==1 ); + assert( (p->exclMask & (1<<ofst))==0 ); + if( (p->sharedMask & mask)==0 ){ + if( aLock[ofst]<0 ){ + rc = SQLITE_BUSY; + }else if( aLock[ofst]==0 ){ + rc = unixShmSystemLock(pDbFd, F_RDLCK, ofst+UNIX_SHM_BASE, n); + } + + /* Get the local shared locks */ + if( rc==SQLITE_OK ){ + p->sharedMask |= mask; + aLock[ofst]++; + } + } + }else{ + /* Make sure no sibling connections hold locks that will block this + ** lock. If any do, return SQLITE_BUSY right away. */ + int ii; + for(ii=ofst; ii<ofst+n; ii++){ + assert( (p->sharedMask & mask)==0 ); + if( ALWAYS((p->exclMask & (1<<ii))==0) && aLock[ii] ){ + rc = SQLITE_BUSY; + break; + } + } + + /* Get the exclusive locks at the system level. Then if successful + ** also update the in-memory values. */ + if( rc==SQLITE_OK ){ + rc = unixShmSystemLock(pDbFd, F_WRLCK, ofst+UNIX_SHM_BASE, n); + if( rc==SQLITE_OK ){ + assert( (p->sharedMask & mask)==0 ); + p->exclMask |= mask; + for(ii=ofst; ii<ofst+n; ii++){ + aLock[ii] = -1; + } + } + } + } + assert( assertLockingArrayOk(pShmNode) ); + sqlite3_mutex_leave(pShmNode->pShmMutex); + OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x\n", + p->id, osGetpid(0), p->sharedMask, p->exclMask)); + return rc; +} + +/* +** Implement a memory barrier or memory fence on shared memory. +** +** All loads and stores begun before the barrier must complete before +** any load or store begun after the barrier. +*/ +static void unixShmBarrier( + sqlite3_file *fd /* Database file holding the shared memory */ +){ + UNUSED_PARAMETER(fd); + sqlite3MemoryBarrier(); /* compiler-defined memory barrier */ + assert( fd->pMethods->xLock==nolockLock + || unixFileMutexNotheld((unixFile*)fd) + ); + unixEnterMutex(); /* Also mutex, for redundancy */ + unixLeaveMutex(); +} + +/* +** Close a connection to shared-memory. Delete the underlying +** storage if deleteFlag is true. +** +** If there is no shared memory associated with the connection then this +** routine is a harmless no-op. +*/ +static int unixShmUnmap( + sqlite3_file *fd, /* The underlying database file */ + int deleteFlag /* Delete shared-memory if true */ +){ + unixShm *p; /* The connection to be closed */ + unixShmNode *pShmNode; /* The underlying shared-memory file */ + unixShm **pp; /* For looping over sibling connections */ + unixFile *pDbFd; /* The underlying database file */ + + pDbFd = (unixFile*)fd; + p = pDbFd->pShm; + if( p==0 ) return SQLITE_OK; + pShmNode = p->pShmNode; + + assert( pShmNode==pDbFd->pInode->pShmNode ); + assert( pShmNode->pInode==pDbFd->pInode ); + + /* Remove connection p from the set of connections associated + ** with pShmNode */ + sqlite3_mutex_enter(pShmNode->pShmMutex); + for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){} + *pp = p->pNext; + + /* Free the connection p */ + sqlite3_free(p); + pDbFd->pShm = 0; + sqlite3_mutex_leave(pShmNode->pShmMutex); + + /* If pShmNode->nRef has reached 0, then close the underlying + ** shared-memory file, too */ + assert( unixFileMutexNotheld(pDbFd) ); + unixEnterMutex(); + assert( pShmNode->nRef>0 ); + pShmNode->nRef--; + if( pShmNode->nRef==0 ){ + if( deleteFlag && pShmNode->hShm>=0 ){ + osUnlink(pShmNode->zFilename); + } + unixShmPurge(pDbFd); + } + unixLeaveMutex(); + + return SQLITE_OK; +} + + +#else +# define unixShmMap 0 +# define unixShmLock 0 +# define unixShmBarrier 0 +# define unixShmUnmap 0 +#endif /* #ifndef SQLITE_OMIT_WAL */ + +#if SQLITE_MAX_MMAP_SIZE>0 +/* +** If it is currently memory mapped, unmap file pFd. +*/ +static void unixUnmapfile(unixFile *pFd){ + assert( pFd->nFetchOut==0 ); + if( pFd->pMapRegion ){ + osMunmap(pFd->pMapRegion, pFd->mmapSizeActual); + pFd->pMapRegion = 0; + pFd->mmapSize = 0; + pFd->mmapSizeActual = 0; + } +} + +/* +** Attempt to set the size of the memory mapping maintained by file +** descriptor pFd to nNew bytes. Any existing mapping is discarded. +** +** If successful, this function sets the following variables: +** +** unixFile.pMapRegion +** unixFile.mmapSize +** unixFile.mmapSizeActual +** +** If unsuccessful, an error message is logged via sqlite3_log() and +** the three variables above are zeroed. In this case SQLite should +** continue accessing the database using the xRead() and xWrite() +** methods. +*/ +static void unixRemapfile( + unixFile *pFd, /* File descriptor object */ + i64 nNew /* Required mapping size */ +){ + const char *zErr = "mmap"; + int h = pFd->h; /* File descriptor open on db file */ + u8 *pOrig = (u8 *)pFd->pMapRegion; /* Pointer to current file mapping */ + i64 nOrig = pFd->mmapSizeActual; /* Size of pOrig region in bytes */ + u8 *pNew = 0; /* Location of new mapping */ + int flags = PROT_READ; /* Flags to pass to mmap() */ + + assert( pFd->nFetchOut==0 ); + assert( nNew>pFd->mmapSize ); + assert( nNew<=pFd->mmapSizeMax ); + assert( nNew>0 ); + assert( pFd->mmapSizeActual>=pFd->mmapSize ); + assert( MAP_FAILED!=0 ); + +#ifdef SQLITE_MMAP_READWRITE + if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE; +#endif + + if( pOrig ){ +#if HAVE_MREMAP + i64 nReuse = pFd->mmapSize; +#else + const int szSyspage = osGetpagesize(); + i64 nReuse = (pFd->mmapSize & ~(szSyspage-1)); +#endif + u8 *pReq = &pOrig[nReuse]; + + /* Unmap any pages of the existing mapping that cannot be reused. */ + if( nReuse!=nOrig ){ + osMunmap(pReq, nOrig-nReuse); + } + +#if HAVE_MREMAP + pNew = osMremap(pOrig, nReuse, nNew, MREMAP_MAYMOVE); + zErr = "mremap"; +#else + pNew = osMmap(pReq, nNew-nReuse, flags, MAP_SHARED, h, nReuse); + if( pNew!=MAP_FAILED ){ + if( pNew!=pReq ){ + osMunmap(pNew, nNew - nReuse); + pNew = 0; + }else{ + pNew = pOrig; + } + } +#endif + + /* The attempt to extend the existing mapping failed. Free it. */ + if( pNew==MAP_FAILED || pNew==0 ){ + osMunmap(pOrig, nReuse); + } + } + + /* If pNew is still NULL, try to create an entirely new mapping. */ + if( pNew==0 ){ + pNew = osMmap(0, nNew, flags, MAP_SHARED, h, 0); + } + + if( pNew==MAP_FAILED ){ + pNew = 0; + nNew = 0; + unixLogError(SQLITE_OK, zErr, pFd->zPath); + + /* If the mmap() above failed, assume that all subsequent mmap() calls + ** will probably fail too. Fall back to using xRead/xWrite exclusively + ** in this case. */ + pFd->mmapSizeMax = 0; + } + pFd->pMapRegion = (void *)pNew; + pFd->mmapSize = pFd->mmapSizeActual = nNew; +} + +/* +** Memory map or remap the file opened by file-descriptor pFd (if the file +** is already mapped, the existing mapping is replaced by the new). Or, if +** there already exists a mapping for this file, and there are still +** outstanding xFetch() references to it, this function is a no-op. +** +** If parameter nByte is non-negative, then it is the requested size of +** the mapping to create. Otherwise, if nByte is less than zero, then the +** requested size is the size of the file on disk. The actual size of the +** created mapping is either the requested size or the value configured +** using SQLITE_FCNTL_MMAP_LIMIT, whichever is smaller. +** +** SQLITE_OK is returned if no error occurs (even if the mapping is not +** recreated as a result of outstanding references) or an SQLite error +** code otherwise. +*/ +static int unixMapfile(unixFile *pFd, i64 nMap){ + assert( nMap>=0 || pFd->nFetchOut==0 ); + assert( nMap>0 || (pFd->mmapSize==0 && pFd->pMapRegion==0) ); + if( pFd->nFetchOut>0 ) return SQLITE_OK; + + if( nMap<0 ){ + struct stat statbuf; /* Low-level file information */ + if( osFstat(pFd->h, &statbuf) ){ + return SQLITE_IOERR_FSTAT; + } + nMap = statbuf.st_size; + } + if( nMap>pFd->mmapSizeMax ){ + nMap = pFd->mmapSizeMax; + } + + assert( nMap>0 || (pFd->mmapSize==0 && pFd->pMapRegion==0) ); + if( nMap!=pFd->mmapSize ){ + unixRemapfile(pFd, nMap); + } + + return SQLITE_OK; +} +#endif /* SQLITE_MAX_MMAP_SIZE>0 */ + +/* +** If possible, return a pointer to a mapping of file fd starting at offset +** iOff. The mapping must be valid for at least nAmt bytes. +** +** If such a pointer can be obtained, store it in *pp and return SQLITE_OK. +** Or, if one cannot but no error occurs, set *pp to 0 and return SQLITE_OK. +** Finally, if an error does occur, return an SQLite error code. The final +** value of *pp is undefined in this case. +** +** If this function does return a pointer, the caller must eventually +** release the reference by calling unixUnfetch(). +*/ +static int unixFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){ +#if SQLITE_MAX_MMAP_SIZE>0 + unixFile *pFd = (unixFile *)fd; /* The underlying database file */ +#endif + *pp = 0; + +#if SQLITE_MAX_MMAP_SIZE>0 + if( pFd->mmapSizeMax>0 ){ + if( pFd->pMapRegion==0 ){ + int rc = unixMapfile(pFd, -1); + if( rc!=SQLITE_OK ) return rc; + } + if( pFd->mmapSize >= iOff+nAmt ){ + *pp = &((u8 *)pFd->pMapRegion)[iOff]; + pFd->nFetchOut++; + } + } +#endif + return SQLITE_OK; +} + +/* +** If the third argument is non-NULL, then this function releases a +** reference obtained by an earlier call to unixFetch(). The second +** argument passed to this function must be the same as the corresponding +** argument that was passed to the unixFetch() invocation. +** +** Or, if the third argument is NULL, then this function is being called +** to inform the VFS layer that, according to POSIX, any existing mapping +** may now be invalid and should be unmapped. +*/ +static int unixUnfetch(sqlite3_file *fd, i64 iOff, void *p){ +#if SQLITE_MAX_MMAP_SIZE>0 + unixFile *pFd = (unixFile *)fd; /* The underlying database file */ + UNUSED_PARAMETER(iOff); + + /* If p==0 (unmap the entire file) then there must be no outstanding + ** xFetch references. Or, if p!=0 (meaning it is an xFetch reference), + ** then there must be at least one outstanding. */ + assert( (p==0)==(pFd->nFetchOut==0) ); + + /* If p!=0, it must match the iOff value. */ + assert( p==0 || p==&((u8 *)pFd->pMapRegion)[iOff] ); + + if( p ){ + pFd->nFetchOut--; + }else{ + unixUnmapfile(pFd); + } + + assert( pFd->nFetchOut>=0 ); +#else + UNUSED_PARAMETER(fd); + UNUSED_PARAMETER(p); + UNUSED_PARAMETER(iOff); +#endif + return SQLITE_OK; +} + +/* +** Here ends the implementation of all sqlite3_file methods. +** +********************** End sqlite3_file Methods ******************************* +******************************************************************************/ + +/* +** This division contains definitions of sqlite3_io_methods objects that +** implement various file locking strategies. It also contains definitions +** of "finder" functions. A finder-function is used to locate the appropriate +** sqlite3_io_methods object for a particular database file. The pAppData +** field of the sqlite3_vfs VFS objects are initialized to be pointers to +** the correct finder-function for that VFS. +** +** Most finder functions return a pointer to a fixed sqlite3_io_methods +** object. The only interesting finder-function is autolockIoFinder, which +** looks at the filesystem type and tries to guess the best locking +** strategy from that. +** +** For finder-function F, two objects are created: +** +** (1) The real finder-function named "FImpt()". +** +** (2) A constant pointer to this function named just "F". +** +** +** A pointer to the F pointer is used as the pAppData value for VFS +** objects. We have to do this instead of letting pAppData point +** directly at the finder-function since C90 rules prevent a void* +** from be cast into a function pointer. +** +** +** Each instance of this macro generates two objects: +** +** * A constant sqlite3_io_methods object call METHOD that has locking +** methods CLOSE, LOCK, UNLOCK, CKRESLOCK. +** +** * An I/O method finder function called FINDER that returns a pointer +** to the METHOD object in the previous bullet. +*/ +#define IOMETHODS(FINDER,METHOD,VERSION,CLOSE,LOCK,UNLOCK,CKLOCK,SHMMAP) \ +static const sqlite3_io_methods METHOD = { \ + VERSION, /* iVersion */ \ + CLOSE, /* xClose */ \ + unixRead, /* xRead */ \ + unixWrite, /* xWrite */ \ + unixTruncate, /* xTruncate */ \ + unixSync, /* xSync */ \ + unixFileSize, /* xFileSize */ \ + LOCK, /* xLock */ \ + UNLOCK, /* xUnlock */ \ + CKLOCK, /* xCheckReservedLock */ \ + unixFileControl, /* xFileControl */ \ + unixSectorSize, /* xSectorSize */ \ + unixDeviceCharacteristics, /* xDeviceCapabilities */ \ + SHMMAP, /* xShmMap */ \ + unixShmLock, /* xShmLock */ \ + unixShmBarrier, /* xShmBarrier */ \ + unixShmUnmap, /* xShmUnmap */ \ + unixFetch, /* xFetch */ \ + unixUnfetch, /* xUnfetch */ \ +}; \ +static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){ \ + UNUSED_PARAMETER(z); UNUSED_PARAMETER(p); \ + return &METHOD; \ +} \ +static const sqlite3_io_methods *(*const FINDER)(const char*,unixFile *p) \ + = FINDER##Impl; + +/* +** Here are all of the sqlite3_io_methods objects for each of the +** locking strategies. Functions that return pointers to these methods +** are also created. +*/ +IOMETHODS( + posixIoFinder, /* Finder function name */ + posixIoMethods, /* sqlite3_io_methods object name */ + 3, /* shared memory and mmap are enabled */ + unixClose, /* xClose method */ + unixLock, /* xLock method */ + unixUnlock, /* xUnlock method */ + unixCheckReservedLock, /* xCheckReservedLock method */ + unixShmMap /* xShmMap method */ +) +IOMETHODS( + nolockIoFinder, /* Finder function name */ + nolockIoMethods, /* sqlite3_io_methods object name */ + 3, /* shared memory and mmap are enabled */ + nolockClose, /* xClose method */ + nolockLock, /* xLock method */ + nolockUnlock, /* xUnlock method */ + nolockCheckReservedLock, /* xCheckReservedLock method */ + 0 /* xShmMap method */ +) +IOMETHODS( + dotlockIoFinder, /* Finder function name */ + dotlockIoMethods, /* sqlite3_io_methods object name */ + 1, /* shared memory is disabled */ + dotlockClose, /* xClose method */ + dotlockLock, /* xLock method */ + dotlockUnlock, /* xUnlock method */ + dotlockCheckReservedLock, /* xCheckReservedLock method */ + 0 /* xShmMap method */ +) + +#if SQLITE_ENABLE_LOCKING_STYLE +IOMETHODS( + flockIoFinder, /* Finder function name */ + flockIoMethods, /* sqlite3_io_methods object name */ + 1, /* shared memory is disabled */ + flockClose, /* xClose method */ + flockLock, /* xLock method */ + flockUnlock, /* xUnlock method */ + flockCheckReservedLock, /* xCheckReservedLock method */ + 0 /* xShmMap method */ +) +#endif + +#if OS_VXWORKS +IOMETHODS( + semIoFinder, /* Finder function name */ + semIoMethods, /* sqlite3_io_methods object name */ + 1, /* shared memory is disabled */ + semXClose, /* xClose method */ + semXLock, /* xLock method */ + semXUnlock, /* xUnlock method */ + semXCheckReservedLock, /* xCheckReservedLock method */ + 0 /* xShmMap method */ +) +#endif + +#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE +IOMETHODS( + afpIoFinder, /* Finder function name */ + afpIoMethods, /* sqlite3_io_methods object name */ + 1, /* shared memory is disabled */ + afpClose, /* xClose method */ + afpLock, /* xLock method */ + afpUnlock, /* xUnlock method */ + afpCheckReservedLock, /* xCheckReservedLock method */ + 0 /* xShmMap method */ +) +#endif + +/* +** The proxy locking method is a "super-method" in the sense that it +** opens secondary file descriptors for the conch and lock files and +** it uses proxy, dot-file, AFP, and flock() locking methods on those +** secondary files. For this reason, the division that implements +** proxy locking is located much further down in the file. But we need +** to go ahead and define the sqlite3_io_methods and finder function +** for proxy locking here. So we forward declare the I/O methods. +*/ +#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE +static int proxyClose(sqlite3_file*); +static int proxyLock(sqlite3_file*, int); +static int proxyUnlock(sqlite3_file*, int); +static int proxyCheckReservedLock(sqlite3_file*, int*); +IOMETHODS( + proxyIoFinder, /* Finder function name */ + proxyIoMethods, /* sqlite3_io_methods object name */ + 1, /* shared memory is disabled */ + proxyClose, /* xClose method */ + proxyLock, /* xLock method */ + proxyUnlock, /* xUnlock method */ + proxyCheckReservedLock, /* xCheckReservedLock method */ + 0 /* xShmMap method */ +) +#endif + +/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */ +#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE +IOMETHODS( + nfsIoFinder, /* Finder function name */ + nfsIoMethods, /* sqlite3_io_methods object name */ + 1, /* shared memory is disabled */ + unixClose, /* xClose method */ + unixLock, /* xLock method */ + nfsUnlock, /* xUnlock method */ + unixCheckReservedLock, /* xCheckReservedLock method */ + 0 /* xShmMap method */ +) +#endif + +#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE +/* +** This "finder" function attempts to determine the best locking strategy +** for the database file "filePath". It then returns the sqlite3_io_methods +** object that implements that strategy. +** +** This is for MacOSX only. +*/ +static const sqlite3_io_methods *autolockIoFinderImpl( + const char *filePath, /* name of the database file */ + unixFile *pNew /* open file object for the database file */ +){ + static const struct Mapping { + const char *zFilesystem; /* Filesystem type name */ + const sqlite3_io_methods *pMethods; /* Appropriate locking method */ + } aMap[] = { + { "hfs", &posixIoMethods }, + { "ufs", &posixIoMethods }, + { "afpfs", &afpIoMethods }, + { "smbfs", &afpIoMethods }, + { "webdav", &nolockIoMethods }, + { 0, 0 } + }; + int i; + struct statfs fsInfo; + struct flock lockInfo; + + if( !filePath ){ + /* If filePath==NULL that means we are dealing with a transient file + ** that does not need to be locked. */ + return &nolockIoMethods; + } + if( statfs(filePath, &fsInfo) != -1 ){ + if( fsInfo.f_flags & MNT_RDONLY ){ + return &nolockIoMethods; + } + for(i=0; aMap[i].zFilesystem; i++){ + if( strcmp(fsInfo.f_fstypename, aMap[i].zFilesystem)==0 ){ + return aMap[i].pMethods; + } + } + } + + /* Default case. Handles, amongst others, "nfs". + ** Test byte-range lock using fcntl(). If the call succeeds, + ** assume that the file-system supports POSIX style locks. + */ + lockInfo.l_len = 1; + lockInfo.l_start = 0; + lockInfo.l_whence = SEEK_SET; + lockInfo.l_type = F_RDLCK; + if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) { + if( strcmp(fsInfo.f_fstypename, "nfs")==0 ){ + return &nfsIoMethods; + } else { + return &posixIoMethods; + } + }else{ + return &dotlockIoMethods; + } +} +static const sqlite3_io_methods + *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl; + +#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ + +#if OS_VXWORKS +/* +** This "finder" function for VxWorks checks to see if posix advisory +** locking works. If it does, then that is what is used. If it does not +** work, then fallback to named semaphore locking. +*/ +static const sqlite3_io_methods *vxworksIoFinderImpl( + const char *filePath, /* name of the database file */ + unixFile *pNew /* the open file object */ +){ + struct flock lockInfo; + + if( !filePath ){ + /* If filePath==NULL that means we are dealing with a transient file + ** that does not need to be locked. */ + return &nolockIoMethods; + } + + /* Test if fcntl() is supported and use POSIX style locks. + ** Otherwise fall back to the named semaphore method. + */ + lockInfo.l_len = 1; + lockInfo.l_start = 0; + lockInfo.l_whence = SEEK_SET; + lockInfo.l_type = F_RDLCK; + if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) { + return &posixIoMethods; + }else{ + return &semIoMethods; + } +} +static const sqlite3_io_methods + *(*const vxworksIoFinder)(const char*,unixFile*) = vxworksIoFinderImpl; + +#endif /* OS_VXWORKS */ + +/* +** An abstract type for a pointer to an IO method finder function: +*/ +typedef const sqlite3_io_methods *(*finder_type)(const char*,unixFile*); + + +/**************************************************************************** +**************************** sqlite3_vfs methods **************************** +** +** This division contains the implementation of methods on the +** sqlite3_vfs object. +*/ + +/* +** Initialize the contents of the unixFile structure pointed to by pId. +*/ +static int fillInUnixFile( + sqlite3_vfs *pVfs, /* Pointer to vfs object */ + int h, /* Open file descriptor of file being opened */ + sqlite3_file *pId, /* Write to the unixFile structure here */ + const char *zFilename, /* Name of the file being opened */ + int ctrlFlags /* Zero or more UNIXFILE_* values */ +){ + const sqlite3_io_methods *pLockingStyle; + unixFile *pNew = (unixFile *)pId; + int rc = SQLITE_OK; + + assert( pNew->pInode==NULL ); + + /* No locking occurs in temporary files */ + assert( zFilename!=0 || (ctrlFlags & UNIXFILE_NOLOCK)!=0 ); + + OSTRACE(("OPEN %-3d %s\n", h, zFilename)); + pNew->h = h; + pNew->pVfs = pVfs; + pNew->zPath = zFilename; + pNew->ctrlFlags = (u8)ctrlFlags; +#if SQLITE_MAX_MMAP_SIZE>0 + pNew->mmapSizeMax = sqlite3GlobalConfig.szMmap; +#endif + if( sqlite3_uri_boolean(((ctrlFlags & UNIXFILE_URI) ? zFilename : 0), + "psow", SQLITE_POWERSAFE_OVERWRITE) ){ + pNew->ctrlFlags |= UNIXFILE_PSOW; + } + if( strcmp(pVfs->zName,"unix-excl")==0 ){ + pNew->ctrlFlags |= UNIXFILE_EXCL; + } + +#if OS_VXWORKS + pNew->pId = vxworksFindFileId(zFilename); + if( pNew->pId==0 ){ + ctrlFlags |= UNIXFILE_NOLOCK; + rc = SQLITE_NOMEM_BKPT; + } +#endif + + if( ctrlFlags & UNIXFILE_NOLOCK ){ + pLockingStyle = &nolockIoMethods; + }else{ + pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew); +#if SQLITE_ENABLE_LOCKING_STYLE + /* Cache zFilename in the locking context (AFP and dotlock override) for + ** proxyLock activation is possible (remote proxy is based on db name) + ** zFilename remains valid until file is closed, to support */ + pNew->lockingContext = (void*)zFilename; +#endif + } + + if( pLockingStyle == &posixIoMethods +#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE + || pLockingStyle == &nfsIoMethods +#endif + ){ + unixEnterMutex(); + rc = findInodeInfo(pNew, &pNew->pInode); + if( rc!=SQLITE_OK ){ + /* If an error occurred in findInodeInfo(), close the file descriptor + ** immediately, before releasing the mutex. findInodeInfo() may fail + ** in two scenarios: + ** + ** (a) A call to fstat() failed. + ** (b) A malloc failed. + ** + ** Scenario (b) may only occur if the process is holding no other + ** file descriptors open on the same file. If there were other file + ** descriptors on this file, then no malloc would be required by + ** findInodeInfo(). If this is the case, it is quite safe to close + ** handle h - as it is guaranteed that no posix locks will be released + ** by doing so. + ** + ** If scenario (a) caused the error then things are not so safe. The + ** implicit assumption here is that if fstat() fails, things are in + ** such bad shape that dropping a lock or two doesn't matter much. + */ + robust_close(pNew, h, __LINE__); + h = -1; + } + unixLeaveMutex(); + } + +#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) + else if( pLockingStyle == &afpIoMethods ){ + /* AFP locking uses the file path so it needs to be included in + ** the afpLockingContext. + */ + afpLockingContext *pCtx; + pNew->lockingContext = pCtx = sqlite3_malloc64( sizeof(*pCtx) ); + if( pCtx==0 ){ + rc = SQLITE_NOMEM_BKPT; + }else{ + /* NB: zFilename exists and remains valid until the file is closed + ** according to requirement F11141. So we do not need to make a + ** copy of the filename. */ + pCtx->dbPath = zFilename; + pCtx->reserved = 0; + srandomdev(); + unixEnterMutex(); + rc = findInodeInfo(pNew, &pNew->pInode); + if( rc!=SQLITE_OK ){ + sqlite3_free(pNew->lockingContext); + robust_close(pNew, h, __LINE__); + h = -1; + } + unixLeaveMutex(); + } + } +#endif + + else if( pLockingStyle == &dotlockIoMethods ){ + /* Dotfile locking uses the file path so it needs to be included in + ** the dotlockLockingContext + */ + char *zLockFile; + int nFilename; + assert( zFilename!=0 ); + nFilename = (int)strlen(zFilename) + 6; + zLockFile = (char *)sqlite3_malloc64(nFilename); + if( zLockFile==0 ){ + rc = SQLITE_NOMEM_BKPT; + }else{ + sqlite3_snprintf(nFilename, zLockFile, "%s" DOTLOCK_SUFFIX, zFilename); + } + pNew->lockingContext = zLockFile; + } + +#if OS_VXWORKS + else if( pLockingStyle == &semIoMethods ){ + /* Named semaphore locking uses the file path so it needs to be + ** included in the semLockingContext + */ + unixEnterMutex(); + rc = findInodeInfo(pNew, &pNew->pInode); + if( (rc==SQLITE_OK) && (pNew->pInode->pSem==NULL) ){ + char *zSemName = pNew->pInode->aSemName; + int n; + sqlite3_snprintf(MAX_PATHNAME, zSemName, "/%s.sem", + pNew->pId->zCanonicalName); + for( n=1; zSemName[n]; n++ ) + if( zSemName[n]=='/' ) zSemName[n] = '_'; + pNew->pInode->pSem = sem_open(zSemName, O_CREAT, 0666, 1); + if( pNew->pInode->pSem == SEM_FAILED ){ + rc = SQLITE_NOMEM_BKPT; + pNew->pInode->aSemName[0] = '\0'; + } + } + unixLeaveMutex(); + } +#endif + + storeLastErrno(pNew, 0); +#if OS_VXWORKS + if( rc!=SQLITE_OK ){ + if( h>=0 ) robust_close(pNew, h, __LINE__); + h = -1; + osUnlink(zFilename); + pNew->ctrlFlags |= UNIXFILE_DELETE; + } +#endif + if( rc!=SQLITE_OK ){ + if( h>=0 ) robust_close(pNew, h, __LINE__); + }else{ + pId->pMethods = pLockingStyle; + OpenCounter(+1); + verifyDbFile(pNew); + } + return rc; +} + +/* +** Directories to consider for temp files. +*/ +static const char *azTempDirs[] = { + 0, + 0, + "/var/tmp", + "/usr/tmp", + "/tmp", + "." +}; + +/* +** Initialize first two members of azTempDirs[] array. +*/ +static void unixTempFileInit(void){ + azTempDirs[0] = getenv("SQLITE_TMPDIR"); + azTempDirs[1] = getenv("TMPDIR"); +} + +/* +** Return the name of a directory in which to put temporary files. +** If no suitable temporary file directory can be found, return NULL. +*/ +static const char *unixTempFileDir(void){ + unsigned int i = 0; + struct stat buf; + const char *zDir = sqlite3_temp_directory; + + while(1){ + if( zDir!=0 + && osStat(zDir, &buf)==0 + && S_ISDIR(buf.st_mode) + && osAccess(zDir, 03)==0 + ){ + return zDir; + } + if( i>=sizeof(azTempDirs)/sizeof(azTempDirs[0]) ) break; + zDir = azTempDirs[i++]; + } + return 0; +} + +/* +** Create a temporary file name in zBuf. zBuf must be allocated +** by the calling process and must be big enough to hold at least +** pVfs->mxPathname bytes. +*/ +static int unixGetTempname(int nBuf, char *zBuf){ + const char *zDir; + int iLimit = 0; + int rc = SQLITE_OK; + + /* It's odd to simulate an io-error here, but really this is just + ** using the io-error infrastructure to test that SQLite handles this + ** function failing. + */ + zBuf[0] = 0; + SimulateIOError( return SQLITE_IOERR ); + + sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR)); + zDir = unixTempFileDir(); + if( zDir==0 ){ + rc = SQLITE_IOERR_GETTEMPPATH; + }else{ + do{ + u64 r; + sqlite3_randomness(sizeof(r), &r); + assert( nBuf>2 ); + zBuf[nBuf-2] = 0; + sqlite3_snprintf(nBuf, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX"%llx%c", + zDir, r, 0); + if( zBuf[nBuf-2]!=0 || (iLimit++)>10 ){ + rc = SQLITE_ERROR; + break; + } + }while( osAccess(zBuf,0)==0 ); + } + sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR)); + return rc; +} + +#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) +/* +** Routine to transform a unixFile into a proxy-locking unixFile. +** Implementation in the proxy-lock division, but used by unixOpen() +** if SQLITE_PREFER_PROXY_LOCKING is defined. +*/ +static int proxyTransformUnixFile(unixFile*, const char*); +#endif + +/* +** Search for an unused file descriptor that was opened on the database +** file (not a journal or super-journal file) identified by pathname +** zPath with SQLITE_OPEN_XXX flags matching those passed as the second +** argument to this function. +** +** Such a file descriptor may exist if a database connection was closed +** but the associated file descriptor could not be closed because some +** other file descriptor open on the same file is holding a file-lock. +** Refer to comments in the unixClose() function and the lengthy comment +** describing "Posix Advisory Locking" at the start of this file for +** further details. Also, ticket #4018. +** +** If a suitable file descriptor is found, then it is returned. If no +** such file descriptor is located, -1 is returned. +*/ +static UnixUnusedFd *findReusableFd(const char *zPath, int flags){ + UnixUnusedFd *pUnused = 0; + + /* Do not search for an unused file descriptor on vxworks. Not because + ** vxworks would not benefit from the change (it might, we're not sure), + ** but because no way to test it is currently available. It is better + ** not to risk breaking vxworks support for the sake of such an obscure + ** feature. */ +#if !OS_VXWORKS + struct stat sStat; /* Results of stat() call */ + + unixEnterMutex(); + + /* A stat() call may fail for various reasons. If this happens, it is + ** almost certain that an open() call on the same path will also fail. + ** For this reason, if an error occurs in the stat() call here, it is + ** ignored and -1 is returned. The caller will try to open a new file + ** descriptor on the same path, fail, and return an error to SQLite. + ** + ** Even if a subsequent open() call does succeed, the consequences of + ** not searching for a reusable file descriptor are not dire. */ + if( inodeList!=0 && 0==osStat(zPath, &sStat) ){ + unixInodeInfo *pInode; + + pInode = inodeList; + while( pInode && (pInode->fileId.dev!=sStat.st_dev + || pInode->fileId.ino!=(u64)sStat.st_ino) ){ + pInode = pInode->pNext; + } + if( pInode ){ + UnixUnusedFd **pp; + assert( sqlite3_mutex_notheld(pInode->pLockMutex) ); + sqlite3_mutex_enter(pInode->pLockMutex); + flags &= (SQLITE_OPEN_READONLY|SQLITE_OPEN_READWRITE); + for(pp=&pInode->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext)); + pUnused = *pp; + if( pUnused ){ + *pp = pUnused->pNext; + } + sqlite3_mutex_leave(pInode->pLockMutex); + } + } + unixLeaveMutex(); +#endif /* if !OS_VXWORKS */ + return pUnused; +} + +/* +** Find the mode, uid and gid of file zFile. +*/ +static int getFileMode( + const char *zFile, /* File name */ + mode_t *pMode, /* OUT: Permissions of zFile */ + uid_t *pUid, /* OUT: uid of zFile. */ + gid_t *pGid /* OUT: gid of zFile. */ +){ + struct stat sStat; /* Output of stat() on database file */ + int rc = SQLITE_OK; + if( 0==osStat(zFile, &sStat) ){ + *pMode = sStat.st_mode & 0777; + *pUid = sStat.st_uid; + *pGid = sStat.st_gid; + }else{ + rc = SQLITE_IOERR_FSTAT; + } + return rc; +} + +/* +** This function is called by unixOpen() to determine the unix permissions +** to create new files with. If no error occurs, then SQLITE_OK is returned +** and a value suitable for passing as the third argument to open(2) is +** written to *pMode. If an IO error occurs, an SQLite error code is +** returned and the value of *pMode is not modified. +** +** In most cases, this routine sets *pMode to 0, which will become +** an indication to robust_open() to create the file using +** SQLITE_DEFAULT_FILE_PERMISSIONS adjusted by the umask. +** But if the file being opened is a WAL or regular journal file, then +** this function queries the file-system for the permissions on the +** corresponding database file and sets *pMode to this value. Whenever +** possible, WAL and journal files are created using the same permissions +** as the associated database file. +** +** If the SQLITE_ENABLE_8_3_NAMES option is enabled, then the +** original filename is unavailable. But 8_3_NAMES is only used for +** FAT filesystems and permissions do not matter there, so just use +** the default permissions. In 8_3_NAMES mode, leave *pMode set to zero. +*/ +static int findCreateFileMode( + const char *zPath, /* Path of file (possibly) being created */ + int flags, /* Flags passed as 4th argument to xOpen() */ + mode_t *pMode, /* OUT: Permissions to open file with */ + uid_t *pUid, /* OUT: uid to set on the file */ + gid_t *pGid /* OUT: gid to set on the file */ +){ + int rc = SQLITE_OK; /* Return Code */ + *pMode = 0; + *pUid = 0; + *pGid = 0; + if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){ + char zDb[MAX_PATHNAME+1]; /* Database file path */ + int nDb; /* Number of valid bytes in zDb */ + + /* zPath is a path to a WAL or journal file. The following block derives + ** the path to the associated database file from zPath. This block handles + ** the following naming conventions: + ** + ** "<path to db>-journal" + ** "<path to db>-wal" + ** "<path to db>-journalNN" + ** "<path to db>-walNN" + ** + ** where NN is a decimal number. The NN naming schemes are + ** used by the test_multiplex.c module. + ** + ** In normal operation, the journal file name will always contain + ** a '-' character. However in 8+3 filename mode, or if a corrupt + ** rollback journal specifies a super-journal with a goofy name, then + ** the '-' might be missing or the '-' might be the first character in + ** the filename. In that case, just return SQLITE_OK with *pMode==0. + */ + nDb = sqlite3Strlen30(zPath) - 1; + while( nDb>0 && zPath[nDb]!='.' ){ + if( zPath[nDb]=='-' ){ + memcpy(zDb, zPath, nDb); + zDb[nDb] = '\0'; + rc = getFileMode(zDb, pMode, pUid, pGid); + break; + } + nDb--; + } + }else if( flags & SQLITE_OPEN_DELETEONCLOSE ){ + *pMode = 0600; + }else if( flags & SQLITE_OPEN_URI ){ + /* If this is a main database file and the file was opened using a URI + ** filename, check for the "modeof" parameter. If present, interpret + ** its value as a filename and try to copy the mode, uid and gid from + ** that file. */ + const char *z = sqlite3_uri_parameter(zPath, "modeof"); + if( z ){ + rc = getFileMode(z, pMode, pUid, pGid); + } + } + return rc; +} + +/* +** Open the file zPath. +** +** Previously, the SQLite OS layer used three functions in place of this +** one: +** +** sqlite3OsOpenReadWrite(); +** sqlite3OsOpenReadOnly(); +** sqlite3OsOpenExclusive(); +** +** These calls correspond to the following combinations of flags: +** +** ReadWrite() -> (READWRITE | CREATE) +** ReadOnly() -> (READONLY) +** OpenExclusive() -> (READWRITE | CREATE | EXCLUSIVE) +** +** The old OpenExclusive() accepted a boolean argument - "delFlag". If +** true, the file was configured to be automatically deleted when the +** file handle closed. To achieve the same effect using this new +** interface, add the DELETEONCLOSE flag to those specified above for +** OpenExclusive(). +*/ +static int unixOpen( + sqlite3_vfs *pVfs, /* The VFS for which this is the xOpen method */ + const char *zPath, /* Pathname of file to be opened */ + sqlite3_file *pFile, /* The file descriptor to be filled in */ + int flags, /* Input flags to control the opening */ + int *pOutFlags /* Output flags returned to SQLite core */ +){ + unixFile *p = (unixFile *)pFile; + int fd = -1; /* File descriptor returned by open() */ + int openFlags = 0; /* Flags to pass to open() */ + int eType = flags&0x0FFF00; /* Type of file to open */ + int noLock; /* True to omit locking primitives */ + int rc = SQLITE_OK; /* Function Return Code */ + int ctrlFlags = 0; /* UNIXFILE_* flags */ + + int isExclusive = (flags & SQLITE_OPEN_EXCLUSIVE); + int isDelete = (flags & SQLITE_OPEN_DELETEONCLOSE); + int isCreate = (flags & SQLITE_OPEN_CREATE); + int isReadonly = (flags & SQLITE_OPEN_READONLY); + int isReadWrite = (flags & SQLITE_OPEN_READWRITE); +#if SQLITE_ENABLE_LOCKING_STYLE + int isAutoProxy = (flags & SQLITE_OPEN_AUTOPROXY); +#endif +#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE + struct statfs fsInfo; +#endif + + /* If creating a super- or main-file journal, this function will open + ** a file-descriptor on the directory too. The first time unixSync() + ** is called the directory file descriptor will be fsync()ed and close()d. + */ + int isNewJrnl = (isCreate && ( + eType==SQLITE_OPEN_SUPER_JOURNAL + || eType==SQLITE_OPEN_MAIN_JOURNAL + || eType==SQLITE_OPEN_WAL + )); + + /* If argument zPath is a NULL pointer, this function is required to open + ** a temporary file. Use this buffer to store the file name in. + */ + char zTmpname[MAX_PATHNAME+2]; + const char *zName = zPath; + + /* Check the following statements are true: + ** + ** (a) Exactly one of the READWRITE and READONLY flags must be set, and + ** (b) if CREATE is set, then READWRITE must also be set, and + ** (c) if EXCLUSIVE is set, then CREATE must also be set. + ** (d) if DELETEONCLOSE is set, then CREATE must also be set. + */ + assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly)); + assert(isCreate==0 || isReadWrite); + assert(isExclusive==0 || isCreate); + assert(isDelete==0 || isCreate); + + /* The main DB, main journal, WAL file and super-journal are never + ** automatically deleted. Nor are they ever temporary files. */ + assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_DB ); + assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_JOURNAL ); + assert( (!isDelete && zName) || eType!=SQLITE_OPEN_SUPER_JOURNAL ); + assert( (!isDelete && zName) || eType!=SQLITE_OPEN_WAL ); + + /* Assert that the upper layer has set one of the "file-type" flags. */ + assert( eType==SQLITE_OPEN_MAIN_DB || eType==SQLITE_OPEN_TEMP_DB + || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL + || eType==SQLITE_OPEN_SUBJOURNAL || eType==SQLITE_OPEN_SUPER_JOURNAL + || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL + ); + + /* Detect a pid change and reset the PRNG. There is a race condition + ** here such that two or more threads all trying to open databases at + ** the same instant might all reset the PRNG. But multiple resets + ** are harmless. + */ + if( randomnessPid!=osGetpid(0) ){ + randomnessPid = osGetpid(0); + sqlite3_randomness(0,0); + } + memset(p, 0, sizeof(unixFile)); + +#ifdef SQLITE_ASSERT_NO_FILES + /* Applications that never read or write a persistent disk files */ + assert( zName==0 ); +#endif + + if( eType==SQLITE_OPEN_MAIN_DB ){ + UnixUnusedFd *pUnused; + pUnused = findReusableFd(zName, flags); + if( pUnused ){ + fd = pUnused->fd; + }else{ + pUnused = sqlite3_malloc64(sizeof(*pUnused)); + if( !pUnused ){ + return SQLITE_NOMEM_BKPT; + } + } + p->pPreallocatedUnused = pUnused; + + /* Database filenames are double-zero terminated if they are not + ** URIs with parameters. Hence, they can always be passed into + ** sqlite3_uri_parameter(). */ + assert( (flags & SQLITE_OPEN_URI) || zName[strlen(zName)+1]==0 ); + + }else if( !zName ){ + /* If zName is NULL, the upper layer is requesting a temp file. */ + assert(isDelete && !isNewJrnl); + rc = unixGetTempname(pVfs->mxPathname, zTmpname); + if( rc!=SQLITE_OK ){ + return rc; + } + zName = zTmpname; + + /* Generated temporary filenames are always double-zero terminated + ** for use by sqlite3_uri_parameter(). */ + assert( zName[strlen(zName)+1]==0 ); + } + + /* Determine the value of the flags parameter passed to POSIX function + ** open(). These must be calculated even if open() is not called, as + ** they may be stored as part of the file handle and used by the + ** 'conch file' locking functions later on. */ + if( isReadonly ) openFlags |= O_RDONLY; + if( isReadWrite ) openFlags |= O_RDWR; + if( isCreate ) openFlags |= O_CREAT; + if( isExclusive ) openFlags |= (O_EXCL|O_NOFOLLOW); + openFlags |= (O_LARGEFILE|O_BINARY|O_NOFOLLOW); + + if( fd<0 ){ + mode_t openMode; /* Permissions to create file with */ + uid_t uid; /* Userid for the file */ + gid_t gid; /* Groupid for the file */ + rc = findCreateFileMode(zName, flags, &openMode, &uid, &gid); + if( rc!=SQLITE_OK ){ + assert( !p->pPreallocatedUnused ); + assert( eType==SQLITE_OPEN_WAL || eType==SQLITE_OPEN_MAIN_JOURNAL ); + return rc; + } + fd = robust_open(zName, openFlags, openMode); + OSTRACE(("OPENX %-3d %s 0%o\n", fd, zName, openFlags)); + assert( !isExclusive || (openFlags & O_CREAT)!=0 ); + if( fd<0 ){ + if( isNewJrnl && errno==EACCES && osAccess(zName, F_OK) ){ + /* If unable to create a journal because the directory is not + ** writable, change the error code to indicate that. */ + rc = SQLITE_READONLY_DIRECTORY; + }else if( errno!=EISDIR && isReadWrite ){ + /* Failed to open the file for read/write access. Try read-only. */ + flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE); + openFlags &= ~(O_RDWR|O_CREAT); + flags |= SQLITE_OPEN_READONLY; + openFlags |= O_RDONLY; + isReadonly = 1; + fd = robust_open(zName, openFlags, openMode); + } + } + if( fd<0 ){ + int rc2 = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zName); + if( rc==SQLITE_OK ) rc = rc2; + goto open_finished; + } + + /* The owner of the rollback journal or WAL file should always be the + ** same as the owner of the database file. Try to ensure that this is + ** the case. The chown() system call will be a no-op if the current + ** process lacks root privileges, be we should at least try. Without + ** this step, if a root process opens a database file, it can leave + ** behinds a journal/WAL that is owned by root and hence make the + ** database inaccessible to unprivileged processes. + ** + ** If openMode==0, then that means uid and gid are not set correctly + ** (probably because SQLite is configured to use 8+3 filename mode) and + ** in that case we do not want to attempt the chown(). + */ + if( openMode && (flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL))!=0 ){ + robustFchown(fd, uid, gid); + } + } + assert( fd>=0 ); + if( pOutFlags ){ + *pOutFlags = flags; + } + + if( p->pPreallocatedUnused ){ + p->pPreallocatedUnused->fd = fd; + p->pPreallocatedUnused->flags = + flags & (SQLITE_OPEN_READONLY|SQLITE_OPEN_READWRITE); + } + + if( isDelete ){ +#if OS_VXWORKS + zPath = zName; +#elif defined(SQLITE_UNLINK_AFTER_CLOSE) + zPath = sqlite3_mprintf("%s", zName); + if( zPath==0 ){ + robust_close(p, fd, __LINE__); + return SQLITE_NOMEM_BKPT; + } +#else + osUnlink(zName); +#endif + } +#if SQLITE_ENABLE_LOCKING_STYLE + else{ + p->openFlags = openFlags; + } +#endif + +#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE + if( fstatfs(fd, &fsInfo) == -1 ){ + storeLastErrno(p, errno); + robust_close(p, fd, __LINE__); + return SQLITE_IOERR_ACCESS; + } + if (0 == strncmp("msdos", fsInfo.f_fstypename, 5)) { + ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS; + } + if (0 == strncmp("exfat", fsInfo.f_fstypename, 5)) { + ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS; + } +#endif + + /* Set up appropriate ctrlFlags */ + if( isDelete ) ctrlFlags |= UNIXFILE_DELETE; + if( isReadonly ) ctrlFlags |= UNIXFILE_RDONLY; + noLock = eType!=SQLITE_OPEN_MAIN_DB; + if( noLock ) ctrlFlags |= UNIXFILE_NOLOCK; + if( isNewJrnl ) ctrlFlags |= UNIXFILE_DIRSYNC; + if( flags & SQLITE_OPEN_URI ) ctrlFlags |= UNIXFILE_URI; + +#if SQLITE_ENABLE_LOCKING_STYLE +#if SQLITE_PREFER_PROXY_LOCKING + isAutoProxy = 1; +#endif + if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){ + char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING"); + int useProxy = 0; + + /* SQLITE_FORCE_PROXY_LOCKING==1 means force always use proxy, 0 means + ** never use proxy, NULL means use proxy for non-local files only. */ + if( envforce!=NULL ){ + useProxy = atoi(envforce)>0; + }else{ + useProxy = !(fsInfo.f_flags&MNT_LOCAL); + } + if( useProxy ){ + rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags); + if( rc==SQLITE_OK ){ + rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:"); + if( rc!=SQLITE_OK ){ + /* Use unixClose to clean up the resources added in fillInUnixFile + ** and clear all the structure's references. Specifically, + ** pFile->pMethods will be NULL so sqlite3OsClose will be a no-op + */ + unixClose(pFile); + return rc; + } + } + goto open_finished; + } + } +#endif + + assert( zPath==0 || zPath[0]=='/' + || eType==SQLITE_OPEN_SUPER_JOURNAL || eType==SQLITE_OPEN_MAIN_JOURNAL + ); + rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags); + +open_finished: + if( rc!=SQLITE_OK ){ + sqlite3_free(p->pPreallocatedUnused); + } + return rc; +} + + +/* +** Delete the file at zPath. If the dirSync argument is true, fsync() +** the directory after deleting the file. +*/ +static int unixDelete( + sqlite3_vfs *NotUsed, /* VFS containing this as the xDelete method */ + const char *zPath, /* Name of file to be deleted */ + int dirSync /* If true, fsync() directory after deleting file */ +){ + int rc = SQLITE_OK; + UNUSED_PARAMETER(NotUsed); + SimulateIOError(return SQLITE_IOERR_DELETE); + if( osUnlink(zPath)==(-1) ){ + if( errno==ENOENT +#if OS_VXWORKS + || osAccess(zPath,0)!=0 +#endif + ){ + rc = SQLITE_IOERR_DELETE_NOENT; + }else{ + rc = unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath); + } + return rc; + } +#ifndef SQLITE_DISABLE_DIRSYNC + if( (dirSync & 1)!=0 ){ + int fd; + rc = osOpenDirectory(zPath, &fd); + if( rc==SQLITE_OK ){ + if( full_fsync(fd,0,0) ){ + rc = unixLogError(SQLITE_IOERR_DIR_FSYNC, "fsync", zPath); + } + robust_close(0, fd, __LINE__); + }else{ + assert( rc==SQLITE_CANTOPEN ); + rc = SQLITE_OK; + } + } +#endif + return rc; +} + +/* +** Test the existence of or access permissions of file zPath. The +** test performed depends on the value of flags: +** +** SQLITE_ACCESS_EXISTS: Return 1 if the file exists +** SQLITE_ACCESS_READWRITE: Return 1 if the file is read and writable. +** SQLITE_ACCESS_READONLY: Return 1 if the file is readable. +** +** Otherwise return 0. +*/ +static int unixAccess( + sqlite3_vfs *NotUsed, /* The VFS containing this xAccess method */ + const char *zPath, /* Path of the file to examine */ + int flags, /* What do we want to learn about the zPath file? */ + int *pResOut /* Write result boolean here */ +){ + UNUSED_PARAMETER(NotUsed); + SimulateIOError( return SQLITE_IOERR_ACCESS; ); + assert( pResOut!=0 ); + + /* The spec says there are three possible values for flags. But only + ** two of them are actually used */ + assert( flags==SQLITE_ACCESS_EXISTS || flags==SQLITE_ACCESS_READWRITE ); + + if( flags==SQLITE_ACCESS_EXISTS ){ + struct stat buf; + *pResOut = 0==osStat(zPath, &buf) && + (!S_ISREG(buf.st_mode) || buf.st_size>0); + }else{ + *pResOut = osAccess(zPath, W_OK|R_OK)==0; + } + return SQLITE_OK; +} + +/* +** A pathname under construction +*/ +typedef struct DbPath DbPath; +struct DbPath { + int rc; /* Non-zero following any error */ + int nSymlink; /* Number of symlinks resolved */ + char *zOut; /* Write the pathname here */ + int nOut; /* Bytes of space available to zOut[] */ + int nUsed; /* Bytes of zOut[] currently being used */ +}; + +/* Forward reference */ +static void appendAllPathElements(DbPath*,const char*); + +/* +** Append a single path element to the DbPath under construction +*/ +static void appendOnePathElement( + DbPath *pPath, /* Path under construction, to which to append zName */ + const char *zName, /* Name to append to pPath. Not zero-terminated */ + int nName /* Number of significant bytes in zName */ +){ + assert( nName>0 ); + assert( zName!=0 ); + if( zName[0]=='.' ){ + if( nName==1 ) return; + if( zName[1]=='.' && nName==2 ){ + if( pPath->nUsed<=1 ){ + pPath->rc = SQLITE_ERROR; + return; + } + assert( pPath->zOut[0]=='/' ); + while( pPath->zOut[--pPath->nUsed]!='/' ){} + return; + } + } + if( pPath->nUsed + nName + 2 >= pPath->nOut ){ + pPath->rc = SQLITE_ERROR; + return; + } + pPath->zOut[pPath->nUsed++] = '/'; + memcpy(&pPath->zOut[pPath->nUsed], zName, nName); + pPath->nUsed += nName; +#if defined(HAVE_READLINK) && defined(HAVE_LSTAT) + if( pPath->rc==SQLITE_OK ){ + const char *zIn; + struct stat buf; + pPath->zOut[pPath->nUsed] = 0; + zIn = pPath->zOut; + if( osLstat(zIn, &buf)!=0 ){ + if( errno!=ENOENT ){ + pPath->rc = unixLogError(SQLITE_CANTOPEN_BKPT, "lstat", zIn); + } + }else if( S_ISLNK(buf.st_mode) ){ + ssize_t got; + char zLnk[SQLITE_MAX_PATHLEN+2]; + if( pPath->nSymlink++ > SQLITE_MAX_SYMLINK ){ + pPath->rc = SQLITE_CANTOPEN_BKPT; + return; + } + got = osReadlink(zIn, zLnk, sizeof(zLnk)-2); + if( got<=0 || got>=(ssize_t)sizeof(zLnk)-2 ){ + pPath->rc = unixLogError(SQLITE_CANTOPEN_BKPT, "readlink", zIn); + return; + } + zLnk[got] = 0; + if( zLnk[0]=='/' ){ + pPath->nUsed = 0; + }else{ + pPath->nUsed -= nName + 1; + } + appendAllPathElements(pPath, zLnk); + } + } +#endif +} + +/* +** Append all path elements in zPath to the DbPath under construction. +*/ +static void appendAllPathElements( + DbPath *pPath, /* Path under construction, to which to append zName */ + const char *zPath /* Path to append to pPath. Is zero-terminated */ +){ + int i = 0; + int j = 0; + do{ + while( zPath[i] && zPath[i]!='/' ){ i++; } + if( i>j ){ + appendOnePathElement(pPath, &zPath[j], i-j); + } + j = i+1; + }while( zPath[i++] ); +} + +/* +** Turn a relative pathname into a full pathname. The relative path +** is stored as a nul-terminated string in the buffer pointed to by +** zPath. +** +** zOut points to a buffer of at least sqlite3_vfs.mxPathname bytes +** (in this case, MAX_PATHNAME bytes). The full-path is written to +** this buffer before returning. +*/ +static int unixFullPathname( + sqlite3_vfs *pVfs, /* Pointer to vfs object */ + const char *zPath, /* Possibly relative input path */ + int nOut, /* Size of output buffer in bytes */ + char *zOut /* Output buffer */ +){ + DbPath path; + UNUSED_PARAMETER(pVfs); + path.rc = 0; + path.nUsed = 0; + path.nSymlink = 0; + path.nOut = nOut; + path.zOut = zOut; + if( zPath[0]!='/' ){ + char zPwd[SQLITE_MAX_PATHLEN+2]; + if( osGetcwd(zPwd, sizeof(zPwd)-2)==0 ){ + return unixLogError(SQLITE_CANTOPEN_BKPT, "getcwd", zPath); + } + appendAllPathElements(&path, zPwd); + } + appendAllPathElements(&path, zPath); + zOut[path.nUsed] = 0; + if( path.rc || path.nUsed<2 ) return SQLITE_CANTOPEN_BKPT; + if( path.nSymlink ) return SQLITE_OK_SYMLINK; + return SQLITE_OK; +} + +#ifndef SQLITE_OMIT_LOAD_EXTENSION +/* +** Interfaces for opening a shared library, finding entry points +** within the shared library, and closing the shared library. +*/ +#include <dlfcn.h> +static void *unixDlOpen(sqlite3_vfs *NotUsed, const char *zFilename){ + UNUSED_PARAMETER(NotUsed); + return dlopen(zFilename, RTLD_NOW | RTLD_GLOBAL); +} + +/* +** SQLite calls this function immediately after a call to unixDlSym() or +** unixDlOpen() fails (returns a null pointer). If a more detailed error +** message is available, it is written to zBufOut. If no error message +** is available, zBufOut is left unmodified and SQLite uses a default +** error message. +*/ +static void unixDlError(sqlite3_vfs *NotUsed, int nBuf, char *zBufOut){ + const char *zErr; + UNUSED_PARAMETER(NotUsed); + unixEnterMutex(); + zErr = dlerror(); + if( zErr ){ + sqlite3_snprintf(nBuf, zBufOut, "%s", zErr); + } + unixLeaveMutex(); +} +static void (*unixDlSym(sqlite3_vfs *NotUsed, void *p, const char*zSym))(void){ + /* + ** GCC with -pedantic-errors says that C90 does not allow a void* to be + ** cast into a pointer to a function. And yet the library dlsym() routine + ** returns a void* which is really a pointer to a function. So how do we + ** use dlsym() with -pedantic-errors? + ** + ** Variable x below is defined to be a pointer to a function taking + ** parameters void* and const char* and returning a pointer to a function. + ** We initialize x by assigning it a pointer to the dlsym() function. + ** (That assignment requires a cast.) Then we call the function that + ** x points to. + ** + ** This work-around is unlikely to work correctly on any system where + ** you really cannot cast a function pointer into void*. But then, on the + ** other hand, dlsym() will not work on such a system either, so we have + ** not really lost anything. + */ + void (*(*x)(void*,const char*))(void); + UNUSED_PARAMETER(NotUsed); + x = (void(*(*)(void*,const char*))(void))dlsym; + return (*x)(p, zSym); +} +static void unixDlClose(sqlite3_vfs *NotUsed, void *pHandle){ + UNUSED_PARAMETER(NotUsed); + dlclose(pHandle); +} +#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */ + #define unixDlOpen 0 + #define unixDlError 0 + #define unixDlSym 0 + #define unixDlClose 0 +#endif + +/* +** Write nBuf bytes of random data to the supplied buffer zBuf. +*/ +static int unixRandomness(sqlite3_vfs *NotUsed, int nBuf, char *zBuf){ + UNUSED_PARAMETER(NotUsed); + assert((size_t)nBuf>=(sizeof(time_t)+sizeof(int))); + + /* We have to initialize zBuf to prevent valgrind from reporting + ** errors. The reports issued by valgrind are incorrect - we would + ** prefer that the randomness be increased by making use of the + ** uninitialized space in zBuf - but valgrind errors tend to worry + ** some users. Rather than argue, it seems easier just to initialize + ** the whole array and silence valgrind, even if that means less randomness + ** in the random seed. + ** + ** When testing, initializing zBuf[] to zero is all we do. That means + ** that we always use the same random number sequence. This makes the + ** tests repeatable. + */ + memset(zBuf, 0, nBuf); + randomnessPid = osGetpid(0); +#if !defined(SQLITE_TEST) && !defined(SQLITE_OMIT_RANDOMNESS) + { + int fd, got; + fd = robust_open("/dev/urandom", O_RDONLY, 0); + if( fd<0 ){ + time_t t; + time(&t); + memcpy(zBuf, &t, sizeof(t)); + memcpy(&zBuf[sizeof(t)], &randomnessPid, sizeof(randomnessPid)); + assert( sizeof(t)+sizeof(randomnessPid)<=(size_t)nBuf ); + nBuf = sizeof(t) + sizeof(randomnessPid); + }else{ + do{ got = osRead(fd, zBuf, nBuf); }while( got<0 && errno==EINTR ); + robust_close(0, fd, __LINE__); + } + } +#endif + return nBuf; +} + + +/* +** Sleep for a little while. Return the amount of time slept. +** The argument is the number of microseconds we want to sleep. +** The return value is the number of microseconds of sleep actually +** requested from the underlying operating system, a number which +** might be greater than or equal to the argument, but not less +** than the argument. +*/ +static int unixSleep(sqlite3_vfs *NotUsed, int microseconds){ +#if OS_VXWORKS + struct timespec sp; + + sp.tv_sec = microseconds / 1000000; + sp.tv_nsec = (microseconds % 1000000) * 1000; + nanosleep(&sp, NULL); + UNUSED_PARAMETER(NotUsed); + return microseconds; +#elif defined(HAVE_USLEEP) && HAVE_USLEEP + if( microseconds>=1000000 ) sleep(microseconds/1000000); + if( microseconds%1000000 ) usleep(microseconds%1000000); + UNUSED_PARAMETER(NotUsed); + return microseconds; +#else + int seconds = (microseconds+999999)/1000000; + sleep(seconds); + UNUSED_PARAMETER(NotUsed); + return seconds*1000000; +#endif +} + +/* +** The following variable, if set to a non-zero value, is interpreted as +** the number of seconds since 1970 and is used to set the result of +** sqlite3OsCurrentTime() during testing. +*/ +#ifdef SQLITE_TEST +int sqlite3_current_time = 0; /* Fake system time in seconds since 1970. */ +#endif + +/* +** Find the current time (in Universal Coordinated Time). Write into *piNow +** the current time and date as a Julian Day number times 86_400_000. In +** other words, write into *piNow the number of milliseconds since the Julian +** epoch of noon in Greenwich on November 24, 4714 B.C according to the +** proleptic Gregorian calendar. +** +** On success, return SQLITE_OK. Return SQLITE_ERROR if the time and date +** cannot be found. +*/ +static int unixCurrentTimeInt64(sqlite3_vfs *NotUsed, sqlite3_int64 *piNow){ + static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000; + int rc = SQLITE_OK; +#if defined(NO_GETTOD) + time_t t; + time(&t); + *piNow = ((sqlite3_int64)t)*1000 + unixEpoch; +#elif OS_VXWORKS + struct timespec sNow; + clock_gettime(CLOCK_REALTIME, &sNow); + *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_nsec/1000000; +#else + struct timeval sNow; + (void)gettimeofday(&sNow, 0); /* Cannot fail given valid arguments */ + *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_usec/1000; +#endif + +#ifdef SQLITE_TEST + if( sqlite3_current_time ){ + *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch; + } +#endif + UNUSED_PARAMETER(NotUsed); + return rc; +} + +#ifndef SQLITE_OMIT_DEPRECATED +/* +** Find the current time (in Universal Coordinated Time). Write the +** current time and date as a Julian Day number into *prNow and +** return 0. Return 1 if the time and date cannot be found. +*/ +static int unixCurrentTime(sqlite3_vfs *NotUsed, double *prNow){ + sqlite3_int64 i = 0; + int rc; + UNUSED_PARAMETER(NotUsed); + rc = unixCurrentTimeInt64(0, &i); + *prNow = i/86400000.0; + return rc; +} +#else +# define unixCurrentTime 0 +#endif + +/* +** The xGetLastError() method is designed to return a better +** low-level error message when operating-system problems come up +** during SQLite operation. Only the integer return code is currently +** used. +*/ +static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){ + UNUSED_PARAMETER(NotUsed); + UNUSED_PARAMETER(NotUsed2); + UNUSED_PARAMETER(NotUsed3); + return errno; +} + + +/* +************************ End of sqlite3_vfs methods *************************** +******************************************************************************/ + +/****************************************************************************** +************************** Begin Proxy Locking ******************************** +** +** Proxy locking is a "uber-locking-method" in this sense: It uses the +** other locking methods on secondary lock files. Proxy locking is a +** meta-layer over top of the primitive locking implemented above. For +** this reason, the division that implements of proxy locking is deferred +** until late in the file (here) after all of the other I/O methods have +** been defined - so that the primitive locking methods are available +** as services to help with the implementation of proxy locking. +** +**** +** +** The default locking schemes in SQLite use byte-range locks on the +** database file to coordinate safe, concurrent access by multiple readers +** and writers [http://sqlite.org/lockingv3.html]. The five file locking +** states (UNLOCKED, PENDING, SHARED, RESERVED, EXCLUSIVE) are implemented +** as POSIX read & write locks over fixed set of locations (via fsctl), +** on AFP and SMB only exclusive byte-range locks are available via fsctl +** with _IOWR('z', 23, struct ByteRangeLockPB2) to track the same 5 states. +** To simulate a F_RDLCK on the shared range, on AFP a randomly selected +** address in the shared range is taken for a SHARED lock, the entire +** shared range is taken for an EXCLUSIVE lock): +** +** PENDING_BYTE 0x40000000 +** RESERVED_BYTE 0x40000001 +** SHARED_RANGE 0x40000002 -> 0x40000200 +** +** This works well on the local file system, but shows a nearly 100x +** slowdown in read performance on AFP because the AFP client disables +** the read cache when byte-range locks are present. Enabling the read +** cache exposes a cache coherency problem that is present on all OS X +** supported network file systems. NFS and AFP both observe the +** close-to-open semantics for ensuring cache coherency +** [http://nfs.sourceforge.net/#faq_a8], which does not effectively +** address the requirements for concurrent database access by multiple +** readers and writers +** [http://www.nabble.com/SQLite-on-NFS-cache-coherency-td15655701.html]. +** +** To address the performance and cache coherency issues, proxy file locking +** changes the way database access is controlled by limiting access to a +** single host at a time and moving file locks off of the database file +** and onto a proxy file on the local file system. +** +** +** Using proxy locks +** ----------------- +** +** C APIs +** +** sqlite3_file_control(db, dbname, SQLITE_FCNTL_SET_LOCKPROXYFILE, +** <proxy_path> | ":auto:"); +** sqlite3_file_control(db, dbname, SQLITE_FCNTL_GET_LOCKPROXYFILE, +** &<proxy_path>); +** +** +** SQL pragmas +** +** PRAGMA [database.]lock_proxy_file=<proxy_path> | :auto: +** PRAGMA [database.]lock_proxy_file +** +** Specifying ":auto:" means that if there is a conch file with a matching +** host ID in it, the proxy path in the conch file will be used, otherwise +** a proxy path based on the user's temp dir +** (via confstr(_CS_DARWIN_USER_TEMP_DIR,...)) will be used and the +** actual proxy file name is generated from the name and path of the +** database file. For example: +** +** For database path "/Users/me/foo.db" +** The lock path will be "<tmpdir>/sqliteplocks/_Users_me_foo.db:auto:") +** +** Once a lock proxy is configured for a database connection, it can not +** be removed, however it may be switched to a different proxy path via +** the above APIs (assuming the conch file is not being held by another +** connection or process). +** +** +** How proxy locking works +** ----------------------- +** +** Proxy file locking relies primarily on two new supporting files: +** +** * conch file to limit access to the database file to a single host +** at a time +** +** * proxy file to act as a proxy for the advisory locks normally +** taken on the database +** +** The conch file - to use a proxy file, sqlite must first "hold the conch" +** by taking an sqlite-style shared lock on the conch file, reading the +** contents and comparing the host's unique host ID (see below) and lock +** proxy path against the values stored in the conch. The conch file is +** stored in the same directory as the database file and the file name +** is patterned after the database file name as ".<databasename>-conch". +** If the conch file does not exist, or its contents do not match the +** host ID and/or proxy path, then the lock is escalated to an exclusive +** lock and the conch file contents is updated with the host ID and proxy +** path and the lock is downgraded to a shared lock again. If the conch +** is held by another process (with a shared lock), the exclusive lock +** will fail and SQLITE_BUSY is returned. +** +** The proxy file - a single-byte file used for all advisory file locks +** normally taken on the database file. This allows for safe sharing +** of the database file for multiple readers and writers on the same +** host (the conch ensures that they all use the same local lock file). +** +** Requesting the lock proxy does not immediately take the conch, it is +** only taken when the first request to lock database file is made. +** This matches the semantics of the traditional locking behavior, where +** opening a connection to a database file does not take a lock on it. +** The shared lock and an open file descriptor are maintained until +** the connection to the database is closed. +** +** The proxy file and the lock file are never deleted so they only need +** to be created the first time they are used. +** +** Configuration options +** --------------------- +** +** SQLITE_PREFER_PROXY_LOCKING +** +** Database files accessed on non-local file systems are +** automatically configured for proxy locking, lock files are +** named automatically using the same logic as +** PRAGMA lock_proxy_file=":auto:" +** +** SQLITE_PROXY_DEBUG +** +** Enables the logging of error messages during host id file +** retrieval and creation +** +** LOCKPROXYDIR +** +** Overrides the default directory used for lock proxy files that +** are named automatically via the ":auto:" setting +** +** SQLITE_DEFAULT_PROXYDIR_PERMISSIONS +** +** Permissions to use when creating a directory for storing the +** lock proxy files, only used when LOCKPROXYDIR is not set. +** +** +** As mentioned above, when compiled with SQLITE_PREFER_PROXY_LOCKING, +** setting the environment variable SQLITE_FORCE_PROXY_LOCKING to 1 will +** force proxy locking to be used for every database file opened, and 0 +** will force automatic proxy locking to be disabled for all database +** files (explicitly calling the SQLITE_FCNTL_SET_LOCKPROXYFILE pragma or +** sqlite_file_control API is not affected by SQLITE_FORCE_PROXY_LOCKING). +*/ + +/* +** Proxy locking is only available on MacOSX +*/ +#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE + +/* +** The proxyLockingContext has the path and file structures for the remote +** and local proxy files in it +*/ +typedef struct proxyLockingContext proxyLockingContext; +struct proxyLockingContext { + unixFile *conchFile; /* Open conch file */ + char *conchFilePath; /* Name of the conch file */ + unixFile *lockProxy; /* Open proxy lock file */ + char *lockProxyPath; /* Name of the proxy lock file */ + char *dbPath; /* Name of the open file */ + int conchHeld; /* 1 if the conch is held, -1 if lockless */ + int nFails; /* Number of conch taking failures */ + void *oldLockingContext; /* Original lockingcontext to restore on close */ + sqlite3_io_methods const *pOldMethod; /* Original I/O methods for close */ +}; + +/* +** The proxy lock file path for the database at dbPath is written into lPath, +** which must point to valid, writable memory large enough for a maxLen length +** file path. +*/ +static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){ + int len; + int dbLen; + int i; + +#ifdef LOCKPROXYDIR + len = strlcpy(lPath, LOCKPROXYDIR, maxLen); +#else +# ifdef _CS_DARWIN_USER_TEMP_DIR + { + if( !confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen) ){ + OSTRACE(("GETLOCKPATH failed %s errno=%d pid=%d\n", + lPath, errno, osGetpid(0))); + return SQLITE_IOERR_LOCK; + } + len = strlcat(lPath, "sqliteplocks", maxLen); + } +# else + len = strlcpy(lPath, "/tmp/", maxLen); +# endif +#endif + + if( lPath[len-1]!='/' ){ + len = strlcat(lPath, "/", maxLen); + } + + /* transform the db path to a unique cache name */ + dbLen = (int)strlen(dbPath); + for( i=0; i<dbLen && (i+len+7)<(int)maxLen; i++){ + char c = dbPath[i]; + lPath[i+len] = (c=='/')?'_':c; + } + lPath[i+len]='\0'; + strlcat(lPath, ":auto:", maxLen); + OSTRACE(("GETLOCKPATH proxy lock path=%s pid=%d\n", lPath, osGetpid(0))); + return SQLITE_OK; +} + +/* + ** Creates the lock file and any missing directories in lockPath + */ +static int proxyCreateLockPath(const char *lockPath){ + int i, len; + char buf[MAXPATHLEN]; + int start = 0; + + assert(lockPath!=NULL); + /* try to create all the intermediate directories */ + len = (int)strlen(lockPath); + buf[0] = lockPath[0]; + for( i=1; i<len; i++ ){ + if( lockPath[i] == '/' && (i - start > 0) ){ + /* only mkdir if leaf dir != "." or "/" or ".." */ + if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/') + || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){ + buf[i]='\0'; + if( osMkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){ + int err=errno; + if( err!=EEXIST ) { + OSTRACE(("CREATELOCKPATH FAILED creating %s, " + "'%s' proxy lock path=%s pid=%d\n", + buf, strerror(err), lockPath, osGetpid(0))); + return err; + } + } + } + start=i+1; + } + buf[i] = lockPath[i]; + } + OSTRACE(("CREATELOCKPATH proxy lock path=%s pid=%d\n",lockPath,osGetpid(0))); + return 0; +} + +/* +** Create a new VFS file descriptor (stored in memory obtained from +** sqlite3_malloc) and open the file named "path" in the file descriptor. +** +** The caller is responsible not only for closing the file descriptor +** but also for freeing the memory associated with the file descriptor. +*/ +static int proxyCreateUnixFile( + const char *path, /* path for the new unixFile */ + unixFile **ppFile, /* unixFile created and returned by ref */ + int islockfile /* if non zero missing dirs will be created */ +) { + int fd = -1; + unixFile *pNew; + int rc = SQLITE_OK; + int openFlags = O_RDWR | O_CREAT | O_NOFOLLOW; + sqlite3_vfs dummyVfs; + int terrno = 0; + UnixUnusedFd *pUnused = NULL; + + /* 1. first try to open/create the file + ** 2. if that fails, and this is a lock file (not-conch), try creating + ** the parent directories and then try again. + ** 3. if that fails, try to open the file read-only + ** otherwise return BUSY (if lock file) or CANTOPEN for the conch file + */ + pUnused = findReusableFd(path, openFlags); + if( pUnused ){ + fd = pUnused->fd; + }else{ + pUnused = sqlite3_malloc64(sizeof(*pUnused)); + if( !pUnused ){ + return SQLITE_NOMEM_BKPT; + } + } + if( fd<0 ){ + fd = robust_open(path, openFlags, 0); + terrno = errno; + if( fd<0 && errno==ENOENT && islockfile ){ + if( proxyCreateLockPath(path) == SQLITE_OK ){ + fd = robust_open(path, openFlags, 0); + } + } + } + if( fd<0 ){ + openFlags = O_RDONLY | O_NOFOLLOW; + fd = robust_open(path, openFlags, 0); + terrno = errno; + } + if( fd<0 ){ + if( islockfile ){ + return SQLITE_BUSY; + } + switch (terrno) { + case EACCES: + return SQLITE_PERM; + case EIO: + return SQLITE_IOERR_LOCK; /* even though it is the conch */ + default: + return SQLITE_CANTOPEN_BKPT; + } + } + + pNew = (unixFile *)sqlite3_malloc64(sizeof(*pNew)); + if( pNew==NULL ){ + rc = SQLITE_NOMEM_BKPT; + goto end_create_proxy; + } + memset(pNew, 0, sizeof(unixFile)); + pNew->openFlags = openFlags; + memset(&dummyVfs, 0, sizeof(dummyVfs)); + dummyVfs.pAppData = (void*)&autolockIoFinder; + dummyVfs.zName = "dummy"; + pUnused->fd = fd; + pUnused->flags = openFlags; + pNew->pPreallocatedUnused = pUnused; + + rc = fillInUnixFile(&dummyVfs, fd, (sqlite3_file*)pNew, path, 0); + if( rc==SQLITE_OK ){ + *ppFile = pNew; + return SQLITE_OK; + } +end_create_proxy: + robust_close(pNew, fd, __LINE__); + sqlite3_free(pNew); + sqlite3_free(pUnused); + return rc; +} + +#ifdef SQLITE_TEST +/* simulate multiple hosts by creating unique hostid file paths */ +int sqlite3_hostid_num = 0; +#endif + +#define PROXY_HOSTIDLEN 16 /* conch file host id length */ + +#if HAVE_GETHOSTUUID +/* Not always defined in the headers as it ought to be */ +extern int gethostuuid(uuid_t id, const struct timespec *wait); +#endif + +/* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN +** bytes of writable memory. +*/ +static int proxyGetHostID(unsigned char *pHostID, int *pError){ + assert(PROXY_HOSTIDLEN == sizeof(uuid_t)); + memset(pHostID, 0, PROXY_HOSTIDLEN); +#if HAVE_GETHOSTUUID + { + struct timespec timeout = {1, 0}; /* 1 sec timeout */ + if( gethostuuid(pHostID, &timeout) ){ + int err = errno; + if( pError ){ + *pError = err; + } + return SQLITE_IOERR; + } + } +#else + UNUSED_PARAMETER(pError); +#endif +#ifdef SQLITE_TEST + /* simulate multiple hosts by creating unique hostid file paths */ + if( sqlite3_hostid_num != 0){ + pHostID[0] = (char)(pHostID[0] + (char)(sqlite3_hostid_num & 0xFF)); + } +#endif + + return SQLITE_OK; +} + +/* The conch file contains the header, host id and lock file path + */ +#define PROXY_CONCHVERSION 2 /* 1-byte header, 16-byte host id, path */ +#define PROXY_HEADERLEN 1 /* conch file header length */ +#define PROXY_PATHINDEX (PROXY_HEADERLEN+PROXY_HOSTIDLEN) +#define PROXY_MAXCONCHLEN (PROXY_HEADERLEN+PROXY_HOSTIDLEN+MAXPATHLEN) + +/* +** Takes an open conch file, copies the contents to a new path and then moves +** it back. The newly created file's file descriptor is assigned to the +** conch file structure and finally the original conch file descriptor is +** closed. Returns zero if successful. +*/ +static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){ + proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; + unixFile *conchFile = pCtx->conchFile; + char tPath[MAXPATHLEN]; + char buf[PROXY_MAXCONCHLEN]; + char *cPath = pCtx->conchFilePath; + size_t readLen = 0; + size_t pathLen = 0; + char errmsg[64] = ""; + int fd = -1; + int rc = -1; + UNUSED_PARAMETER(myHostID); + + /* create a new path by replace the trailing '-conch' with '-break' */ + pathLen = strlcpy(tPath, cPath, MAXPATHLEN); + if( pathLen>MAXPATHLEN || pathLen<6 || + (strlcpy(&tPath[pathLen-5], "break", 6) != 5) ){ + sqlite3_snprintf(sizeof(errmsg),errmsg,"path error (len %d)",(int)pathLen); + goto end_breaklock; + } + /* read the conch content */ + readLen = osPread(conchFile->h, buf, PROXY_MAXCONCHLEN, 0); + if( readLen<PROXY_PATHINDEX ){ + sqlite3_snprintf(sizeof(errmsg),errmsg,"read error (len %d)",(int)readLen); + goto end_breaklock; + } + /* write it out to the temporary break file */ + fd = robust_open(tPath, (O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW), 0); + if( fd<0 ){ + sqlite3_snprintf(sizeof(errmsg), errmsg, "create failed (%d)", errno); + goto end_breaklock; + } + if( osPwrite(fd, buf, readLen, 0) != (ssize_t)readLen ){ + sqlite3_snprintf(sizeof(errmsg), errmsg, "write failed (%d)", errno); + goto end_breaklock; + } + if( rename(tPath, cPath) ){ + sqlite3_snprintf(sizeof(errmsg), errmsg, "rename failed (%d)", errno); + goto end_breaklock; + } + rc = 0; + fprintf(stderr, "broke stale lock on %s\n", cPath); + robust_close(pFile, conchFile->h, __LINE__); + conchFile->h = fd; + conchFile->openFlags = O_RDWR | O_CREAT; + +end_breaklock: + if( rc ){ + if( fd>=0 ){ + osUnlink(tPath); + robust_close(pFile, fd, __LINE__); + } + fprintf(stderr, "failed to break stale lock on %s, %s\n", cPath, errmsg); + } + return rc; +} + +/* Take the requested lock on the conch file and break a stale lock if the +** host id matches. +*/ +static int proxyConchLock(unixFile *pFile, uuid_t myHostID, int lockType){ + proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; + unixFile *conchFile = pCtx->conchFile; + int rc = SQLITE_OK; + int nTries = 0; + struct timespec conchModTime; + + memset(&conchModTime, 0, sizeof(conchModTime)); + do { + rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType); + nTries ++; + if( rc==SQLITE_BUSY ){ + /* If the lock failed (busy): + * 1st try: get the mod time of the conch, wait 0.5s and try again. + * 2nd try: fail if the mod time changed or host id is different, wait + * 10 sec and try again + * 3rd try: break the lock unless the mod time has changed. + */ + struct stat buf; + if( osFstat(conchFile->h, &buf) ){ + storeLastErrno(pFile, errno); + return SQLITE_IOERR_LOCK; + } + + if( nTries==1 ){ + conchModTime = buf.st_mtimespec; + unixSleep(0,500000); /* wait 0.5 sec and try the lock again*/ + continue; + } + + assert( nTries>1 ); + if( conchModTime.tv_sec != buf.st_mtimespec.tv_sec || + conchModTime.tv_nsec != buf.st_mtimespec.tv_nsec ){ + return SQLITE_BUSY; + } + + if( nTries==2 ){ + char tBuf[PROXY_MAXCONCHLEN]; + int len = osPread(conchFile->h, tBuf, PROXY_MAXCONCHLEN, 0); + if( len<0 ){ + storeLastErrno(pFile, errno); + return SQLITE_IOERR_LOCK; + } + if( len>PROXY_PATHINDEX && tBuf[0]==(char)PROXY_CONCHVERSION){ + /* don't break the lock if the host id doesn't match */ + if( 0!=memcmp(&tBuf[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN) ){ + return SQLITE_BUSY; + } + }else{ + /* don't break the lock on short read or a version mismatch */ + return SQLITE_BUSY; + } + unixSleep(0,10000000); /* wait 10 sec and try the lock again */ + continue; + } + + assert( nTries==3 ); + if( 0==proxyBreakConchLock(pFile, myHostID) ){ + rc = SQLITE_OK; + if( lockType==EXCLUSIVE_LOCK ){ + rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, SHARED_LOCK); + } + if( !rc ){ + rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType); + } + } + } + } while( rc==SQLITE_BUSY && nTries<3 ); + + return rc; +} + +/* Takes the conch by taking a shared lock and read the contents conch, if +** lockPath is non-NULL, the host ID and lock file path must match. A NULL +** lockPath means that the lockPath in the conch file will be used if the +** host IDs match, or a new lock path will be generated automatically +** and written to the conch file. +*/ +static int proxyTakeConch(unixFile *pFile){ + proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; + + if( pCtx->conchHeld!=0 ){ + return SQLITE_OK; + }else{ + unixFile *conchFile = pCtx->conchFile; + uuid_t myHostID; + int pError = 0; + char readBuf[PROXY_MAXCONCHLEN]; + char lockPath[MAXPATHLEN]; + char *tempLockPath = NULL; + int rc = SQLITE_OK; + int createConch = 0; + int hostIdMatch = 0; + int readLen = 0; + int tryOldLockPath = 0; + int forceNewLockPath = 0; + + OSTRACE(("TAKECONCH %d for %s pid=%d\n", conchFile->h, + (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), + osGetpid(0))); + + rc = proxyGetHostID(myHostID, &pError); + if( (rc&0xff)==SQLITE_IOERR ){ + storeLastErrno(pFile, pError); + goto end_takeconch; + } + rc = proxyConchLock(pFile, myHostID, SHARED_LOCK); + if( rc!=SQLITE_OK ){ + goto end_takeconch; + } + /* read the existing conch file */ + readLen = seekAndRead((unixFile*)conchFile, 0, readBuf, PROXY_MAXCONCHLEN); + if( readLen<0 ){ + /* I/O error: lastErrno set by seekAndRead */ + storeLastErrno(pFile, conchFile->lastErrno); + rc = SQLITE_IOERR_READ; + goto end_takeconch; + }else if( readLen<=(PROXY_HEADERLEN+PROXY_HOSTIDLEN) || + readBuf[0]!=(char)PROXY_CONCHVERSION ){ + /* a short read or version format mismatch means we need to create a new + ** conch file. + */ + createConch = 1; + } + /* if the host id matches and the lock path already exists in the conch + ** we'll try to use the path there, if we can't open that path, we'll + ** retry with a new auto-generated path + */ + do { /* in case we need to try again for an :auto: named lock file */ + + if( !createConch && !forceNewLockPath ){ + hostIdMatch = !memcmp(&readBuf[PROXY_HEADERLEN], myHostID, + PROXY_HOSTIDLEN); + /* if the conch has data compare the contents */ + if( !pCtx->lockProxyPath ){ + /* for auto-named local lock file, just check the host ID and we'll + ** use the local lock file path that's already in there + */ + if( hostIdMatch ){ + size_t pathLen = (readLen - PROXY_PATHINDEX); + + if( pathLen>=MAXPATHLEN ){ + pathLen=MAXPATHLEN-1; + } + memcpy(lockPath, &readBuf[PROXY_PATHINDEX], pathLen); + lockPath[pathLen] = 0; + tempLockPath = lockPath; + tryOldLockPath = 1; + /* create a copy of the lock path if the conch is taken */ + goto end_takeconch; + } + }else if( hostIdMatch + && !strncmp(pCtx->lockProxyPath, &readBuf[PROXY_PATHINDEX], + readLen-PROXY_PATHINDEX) + ){ + /* conch host and lock path match */ + goto end_takeconch; + } + } + + /* if the conch isn't writable and doesn't match, we can't take it */ + if( (conchFile->openFlags&O_RDWR) == 0 ){ + rc = SQLITE_BUSY; + goto end_takeconch; + } + + /* either the conch didn't match or we need to create a new one */ + if( !pCtx->lockProxyPath ){ + proxyGetLockPath(pCtx->dbPath, lockPath, MAXPATHLEN); + tempLockPath = lockPath; + /* create a copy of the lock path _only_ if the conch is taken */ + } + + /* update conch with host and path (this will fail if other process + ** has a shared lock already), if the host id matches, use the big + ** stick. + */ + futimes(conchFile->h, NULL); + if( hostIdMatch && !createConch ){ + if( conchFile->pInode && conchFile->pInode->nShared>1 ){ + /* We are trying for an exclusive lock but another thread in this + ** same process is still holding a shared lock. */ + rc = SQLITE_BUSY; + } else { + rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK); + } + }else{ + rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK); + } + if( rc==SQLITE_OK ){ + char writeBuffer[PROXY_MAXCONCHLEN]; + int writeSize = 0; + + writeBuffer[0] = (char)PROXY_CONCHVERSION; + memcpy(&writeBuffer[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN); + if( pCtx->lockProxyPath!=NULL ){ + strlcpy(&writeBuffer[PROXY_PATHINDEX], pCtx->lockProxyPath, + MAXPATHLEN); + }else{ + strlcpy(&writeBuffer[PROXY_PATHINDEX], tempLockPath, MAXPATHLEN); + } + writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]); + robust_ftruncate(conchFile->h, writeSize); + rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0); + full_fsync(conchFile->h,0,0); + /* If we created a new conch file (not just updated the contents of a + ** valid conch file), try to match the permissions of the database + */ + if( rc==SQLITE_OK && createConch ){ + struct stat buf; + int err = osFstat(pFile->h, &buf); + if( err==0 ){ + mode_t cmode = buf.st_mode&(S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP | + S_IROTH|S_IWOTH); + /* try to match the database file R/W permissions, ignore failure */ +#ifndef SQLITE_PROXY_DEBUG + osFchmod(conchFile->h, cmode); +#else + do{ + rc = osFchmod(conchFile->h, cmode); + }while( rc==(-1) && errno==EINTR ); + if( rc!=0 ){ + int code = errno; + fprintf(stderr, "fchmod %o FAILED with %d %s\n", + cmode, code, strerror(code)); + } else { + fprintf(stderr, "fchmod %o SUCCEDED\n",cmode); + } + }else{ + int code = errno; + fprintf(stderr, "STAT FAILED[%d] with %d %s\n", + err, code, strerror(code)); +#endif + } + } + } + conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK); + + end_takeconch: + OSTRACE(("TRANSPROXY: CLOSE %d\n", pFile->h)); + if( rc==SQLITE_OK && pFile->openFlags ){ + int fd; + if( pFile->h>=0 ){ + robust_close(pFile, pFile->h, __LINE__); + } + pFile->h = -1; + fd = robust_open(pCtx->dbPath, pFile->openFlags, 0); + OSTRACE(("TRANSPROXY: OPEN %d\n", fd)); + if( fd>=0 ){ + pFile->h = fd; + }else{ + rc=SQLITE_CANTOPEN_BKPT; /* SQLITE_BUSY? proxyTakeConch called + during locking */ + } + } + if( rc==SQLITE_OK && !pCtx->lockProxy ){ + char *path = tempLockPath ? tempLockPath : pCtx->lockProxyPath; + rc = proxyCreateUnixFile(path, &pCtx->lockProxy, 1); + if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && tryOldLockPath ){ + /* we couldn't create the proxy lock file with the old lock file path + ** so try again via auto-naming + */ + forceNewLockPath = 1; + tryOldLockPath = 0; + continue; /* go back to the do {} while start point, try again */ + } + } + if( rc==SQLITE_OK ){ + /* Need to make a copy of path if we extracted the value + ** from the conch file or the path was allocated on the stack + */ + if( tempLockPath ){ + pCtx->lockProxyPath = sqlite3DbStrDup(0, tempLockPath); + if( !pCtx->lockProxyPath ){ + rc = SQLITE_NOMEM_BKPT; + } + } + } + if( rc==SQLITE_OK ){ + pCtx->conchHeld = 1; + + if( pCtx->lockProxy->pMethod == &afpIoMethods ){ + afpLockingContext *afpCtx; + afpCtx = (afpLockingContext *)pCtx->lockProxy->lockingContext; + afpCtx->dbPath = pCtx->lockProxyPath; + } + } else { + conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK); + } + OSTRACE(("TAKECONCH %d %s\n", conchFile->h, + rc==SQLITE_OK?"ok":"failed")); + return rc; + } while (1); /* in case we need to retry the :auto: lock file - + ** we should never get here except via the 'continue' call. */ + } +} + +/* +** If pFile holds a lock on a conch file, then release that lock. +*/ +static int proxyReleaseConch(unixFile *pFile){ + int rc = SQLITE_OK; /* Subroutine return code */ + proxyLockingContext *pCtx; /* The locking context for the proxy lock */ + unixFile *conchFile; /* Name of the conch file */ + + pCtx = (proxyLockingContext *)pFile->lockingContext; + conchFile = pCtx->conchFile; + OSTRACE(("RELEASECONCH %d for %s pid=%d\n", conchFile->h, + (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), + osGetpid(0))); + if( pCtx->conchHeld>0 ){ + rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK); + } + pCtx->conchHeld = 0; + OSTRACE(("RELEASECONCH %d %s\n", conchFile->h, + (rc==SQLITE_OK ? "ok" : "failed"))); + return rc; +} + +/* +** Given the name of a database file, compute the name of its conch file. +** Store the conch filename in memory obtained from sqlite3_malloc64(). +** Make *pConchPath point to the new name. Return SQLITE_OK on success +** or SQLITE_NOMEM if unable to obtain memory. +** +** The caller is responsible for ensuring that the allocated memory +** space is eventually freed. +** +** *pConchPath is set to NULL if a memory allocation error occurs. +*/ +static int proxyCreateConchPathname(char *dbPath, char **pConchPath){ + int i; /* Loop counter */ + int len = (int)strlen(dbPath); /* Length of database filename - dbPath */ + char *conchPath; /* buffer in which to construct conch name */ + + /* Allocate space for the conch filename and initialize the name to + ** the name of the original database file. */ + *pConchPath = conchPath = (char *)sqlite3_malloc64(len + 8); + if( conchPath==0 ){ + return SQLITE_NOMEM_BKPT; + } + memcpy(conchPath, dbPath, len+1); + + /* now insert a "." before the last / character */ + for( i=(len-1); i>=0; i-- ){ + if( conchPath[i]=='/' ){ + i++; + break; + } + } + conchPath[i]='.'; + while ( i<len ){ + conchPath[i+1]=dbPath[i]; + i++; + } + + /* append the "-conch" suffix to the file */ + memcpy(&conchPath[i+1], "-conch", 7); + assert( (int)strlen(conchPath) == len+7 ); + + return SQLITE_OK; +} + + +/* Takes a fully configured proxy locking-style unix file and switches +** the local lock file path +*/ +static int switchLockProxyPath(unixFile *pFile, const char *path) { + proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext; + char *oldPath = pCtx->lockProxyPath; + int rc = SQLITE_OK; + + if( pFile->eFileLock!=NO_LOCK ){ + return SQLITE_BUSY; + } + + /* nothing to do if the path is NULL, :auto: or matches the existing path */ + if( !path || path[0]=='\0' || !strcmp(path, ":auto:") || + (oldPath && !strncmp(oldPath, path, MAXPATHLEN)) ){ + return SQLITE_OK; + }else{ + unixFile *lockProxy = pCtx->lockProxy; + pCtx->lockProxy=NULL; + pCtx->conchHeld = 0; + if( lockProxy!=NULL ){ + rc=lockProxy->pMethod->xClose((sqlite3_file *)lockProxy); + if( rc ) return rc; + sqlite3_free(lockProxy); + } + sqlite3_free(oldPath); + pCtx->lockProxyPath = sqlite3DbStrDup(0, path); + } + + return rc; +} + +/* +** pFile is a file that has been opened by a prior xOpen call. dbPath +** is a string buffer at least MAXPATHLEN+1 characters in size. +** +** This routine find the filename associated with pFile and writes it +** int dbPath. +*/ +static int proxyGetDbPathForUnixFile(unixFile *pFile, char *dbPath){ +#if defined(__APPLE__) + if( pFile->pMethod == &afpIoMethods ){ + /* afp style keeps a reference to the db path in the filePath field + ** of the struct */ + assert( (int)strlen((char*)pFile->lockingContext)<=MAXPATHLEN ); + strlcpy(dbPath, ((afpLockingContext *)pFile->lockingContext)->dbPath, + MAXPATHLEN); + } else +#endif + if( pFile->pMethod == &dotlockIoMethods ){ + /* dot lock style uses the locking context to store the dot lock + ** file path */ + int len = strlen((char *)pFile->lockingContext) - strlen(DOTLOCK_SUFFIX); + memcpy(dbPath, (char *)pFile->lockingContext, len + 1); + }else{ + /* all other styles use the locking context to store the db file path */ + assert( strlen((char*)pFile->lockingContext)<=MAXPATHLEN ); + strlcpy(dbPath, (char *)pFile->lockingContext, MAXPATHLEN); + } + return SQLITE_OK; +} + +/* +** Takes an already filled in unix file and alters it so all file locking +** will be performed on the local proxy lock file. The following fields +** are preserved in the locking context so that they can be restored and +** the unix structure properly cleaned up at close time: +** ->lockingContext +** ->pMethod +*/ +static int proxyTransformUnixFile(unixFile *pFile, const char *path) { + proxyLockingContext *pCtx; + char dbPath[MAXPATHLEN+1]; /* Name of the database file */ + char *lockPath=NULL; + int rc = SQLITE_OK; + + if( pFile->eFileLock!=NO_LOCK ){ + return SQLITE_BUSY; + } + proxyGetDbPathForUnixFile(pFile, dbPath); + if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ){ + lockPath=NULL; + }else{ + lockPath=(char *)path; + } + + OSTRACE(("TRANSPROXY %d for %s pid=%d\n", pFile->h, + (lockPath ? lockPath : ":auto:"), osGetpid(0))); + + pCtx = sqlite3_malloc64( sizeof(*pCtx) ); + if( pCtx==0 ){ + return SQLITE_NOMEM_BKPT; + } + memset(pCtx, 0, sizeof(*pCtx)); + + rc = proxyCreateConchPathname(dbPath, &pCtx->conchFilePath); + if( rc==SQLITE_OK ){ + rc = proxyCreateUnixFile(pCtx->conchFilePath, &pCtx->conchFile, 0); + if( rc==SQLITE_CANTOPEN && ((pFile->openFlags&O_RDWR) == 0) ){ + /* if (a) the open flags are not O_RDWR, (b) the conch isn't there, and + ** (c) the file system is read-only, then enable no-locking access. + ** Ugh, since O_RDONLY==0x0000 we test for !O_RDWR since unixOpen asserts + ** that openFlags will have only one of O_RDONLY or O_RDWR. + */ + struct statfs fsInfo; + struct stat conchInfo; + int goLockless = 0; + + if( osStat(pCtx->conchFilePath, &conchInfo) == -1 ) { + int err = errno; + if( (err==ENOENT) && (statfs(dbPath, &fsInfo) != -1) ){ + goLockless = (fsInfo.f_flags&MNT_RDONLY) == MNT_RDONLY; + } + } + if( goLockless ){ + pCtx->conchHeld = -1; /* read only FS/ lockless */ + rc = SQLITE_OK; + } + } + } + if( rc==SQLITE_OK && lockPath ){ + pCtx->lockProxyPath = sqlite3DbStrDup(0, lockPath); + } + + if( rc==SQLITE_OK ){ + pCtx->dbPath = sqlite3DbStrDup(0, dbPath); + if( pCtx->dbPath==NULL ){ + rc = SQLITE_NOMEM_BKPT; + } + } + if( rc==SQLITE_OK ){ + /* all memory is allocated, proxys are created and assigned, + ** switch the locking context and pMethod then return. + */ + pCtx->oldLockingContext = pFile->lockingContext; + pFile->lockingContext = pCtx; + pCtx->pOldMethod = pFile->pMethod; + pFile->pMethod = &proxyIoMethods; + }else{ + if( pCtx->conchFile ){ + pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile); + sqlite3_free(pCtx->conchFile); + } + sqlite3DbFree(0, pCtx->lockProxyPath); + sqlite3_free(pCtx->conchFilePath); + sqlite3_free(pCtx); + } + OSTRACE(("TRANSPROXY %d %s\n", pFile->h, + (rc==SQLITE_OK ? "ok" : "failed"))); + return rc; +} + + +/* +** This routine handles sqlite3_file_control() calls that are specific +** to proxy locking. +*/ +static int proxyFileControl(sqlite3_file *id, int op, void *pArg){ + switch( op ){ + case SQLITE_FCNTL_GET_LOCKPROXYFILE: { + unixFile *pFile = (unixFile*)id; + if( pFile->pMethod == &proxyIoMethods ){ + proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext; + proxyTakeConch(pFile); + if( pCtx->lockProxyPath ){ + *(const char **)pArg = pCtx->lockProxyPath; + }else{ + *(const char **)pArg = ":auto: (not held)"; + } + } else { + *(const char **)pArg = NULL; + } + return SQLITE_OK; + } + case SQLITE_FCNTL_SET_LOCKPROXYFILE: { + unixFile *pFile = (unixFile*)id; + int rc = SQLITE_OK; + int isProxyStyle = (pFile->pMethod == &proxyIoMethods); + if( pArg==NULL || (const char *)pArg==0 ){ + if( isProxyStyle ){ + /* turn off proxy locking - not supported. If support is added for + ** switching proxy locking mode off then it will need to fail if + ** the journal mode is WAL mode. + */ + rc = SQLITE_ERROR /*SQLITE_PROTOCOL? SQLITE_MISUSE?*/; + }else{ + /* turn off proxy locking - already off - NOOP */ + rc = SQLITE_OK; + } + }else{ + const char *proxyPath = (const char *)pArg; + if( isProxyStyle ){ + proxyLockingContext *pCtx = + (proxyLockingContext*)pFile->lockingContext; + if( !strcmp(pArg, ":auto:") + || (pCtx->lockProxyPath && + !strncmp(pCtx->lockProxyPath, proxyPath, MAXPATHLEN)) + ){ + rc = SQLITE_OK; + }else{ + rc = switchLockProxyPath(pFile, proxyPath); + } + }else{ + /* turn on proxy file locking */ + rc = proxyTransformUnixFile(pFile, proxyPath); + } + } + return rc; + } + default: { + assert( 0 ); /* The call assures that only valid opcodes are sent */ + } + } + /*NOTREACHED*/ assert(0); + return SQLITE_ERROR; +} + +/* +** Within this division (the proxying locking implementation) the procedures +** above this point are all utilities. The lock-related methods of the +** proxy-locking sqlite3_io_method object follow. +*/ + + +/* +** This routine checks if there is a RESERVED lock held on the specified +** file by this or any other process. If such a lock is held, set *pResOut +** to a non-zero value otherwise *pResOut is set to zero. The return value +** is set to SQLITE_OK unless an I/O error occurs during lock checking. +*/ +static int proxyCheckReservedLock(sqlite3_file *id, int *pResOut) { + unixFile *pFile = (unixFile*)id; + int rc = proxyTakeConch(pFile); + if( rc==SQLITE_OK ){ + proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; + if( pCtx->conchHeld>0 ){ + unixFile *proxy = pCtx->lockProxy; + return proxy->pMethod->xCheckReservedLock((sqlite3_file*)proxy, pResOut); + }else{ /* conchHeld < 0 is lockless */ + pResOut=0; + } + } + return rc; +} + +/* +** Lock the file with the lock specified by parameter eFileLock - one +** of the following: +** +** (1) SHARED_LOCK +** (2) RESERVED_LOCK +** (3) PENDING_LOCK +** (4) EXCLUSIVE_LOCK +** +** Sometimes when requesting one lock state, additional lock states +** are inserted in between. The locking might fail on one of the later +** transitions leaving the lock state different from what it started but +** still short of its goal. The following chart shows the allowed +** transitions and the inserted intermediate states: +** +** UNLOCKED -> SHARED +** SHARED -> RESERVED +** SHARED -> (PENDING) -> EXCLUSIVE +** RESERVED -> (PENDING) -> EXCLUSIVE +** PENDING -> EXCLUSIVE +** +** This routine will only increase a lock. Use the sqlite3OsUnlock() +** routine to lower a locking level. +*/ +static int proxyLock(sqlite3_file *id, int eFileLock) { + unixFile *pFile = (unixFile*)id; + int rc = proxyTakeConch(pFile); + if( rc==SQLITE_OK ){ + proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; + if( pCtx->conchHeld>0 ){ + unixFile *proxy = pCtx->lockProxy; + rc = proxy->pMethod->xLock((sqlite3_file*)proxy, eFileLock); + pFile->eFileLock = proxy->eFileLock; + }else{ + /* conchHeld < 0 is lockless */ + } + } + return rc; +} + + +/* +** Lower the locking level on file descriptor pFile to eFileLock. eFileLock +** must be either NO_LOCK or SHARED_LOCK. +** +** If the locking level of the file descriptor is already at or below +** the requested locking level, this routine is a no-op. +*/ +static int proxyUnlock(sqlite3_file *id, int eFileLock) { + unixFile *pFile = (unixFile*)id; + int rc = proxyTakeConch(pFile); + if( rc==SQLITE_OK ){ + proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; + if( pCtx->conchHeld>0 ){ + unixFile *proxy = pCtx->lockProxy; + rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, eFileLock); + pFile->eFileLock = proxy->eFileLock; + }else{ + /* conchHeld < 0 is lockless */ + } + } + return rc; +} + +/* +** Close a file that uses proxy locks. +*/ +static int proxyClose(sqlite3_file *id) { + if( ALWAYS(id) ){ + unixFile *pFile = (unixFile*)id; + proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; + unixFile *lockProxy = pCtx->lockProxy; + unixFile *conchFile = pCtx->conchFile; + int rc = SQLITE_OK; + + if( lockProxy ){ + rc = lockProxy->pMethod->xUnlock((sqlite3_file*)lockProxy, NO_LOCK); + if( rc ) return rc; + rc = lockProxy->pMethod->xClose((sqlite3_file*)lockProxy); + if( rc ) return rc; + sqlite3_free(lockProxy); + pCtx->lockProxy = 0; + } + if( conchFile ){ + if( pCtx->conchHeld ){ + rc = proxyReleaseConch(pFile); + if( rc ) return rc; + } + rc = conchFile->pMethod->xClose((sqlite3_file*)conchFile); + if( rc ) return rc; + sqlite3_free(conchFile); + } + sqlite3DbFree(0, pCtx->lockProxyPath); + sqlite3_free(pCtx->conchFilePath); + sqlite3DbFree(0, pCtx->dbPath); + /* restore the original locking context and pMethod then close it */ + pFile->lockingContext = pCtx->oldLockingContext; + pFile->pMethod = pCtx->pOldMethod; + sqlite3_free(pCtx); + return pFile->pMethod->xClose(id); + } + return SQLITE_OK; +} + + + +#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */ +/* +** The proxy locking style is intended for use with AFP filesystems. +** And since AFP is only supported on MacOSX, the proxy locking is also +** restricted to MacOSX. +** +** +******************* End of the proxy lock implementation ********************** +******************************************************************************/ + +/* +** Initialize the operating system interface. +** +** This routine registers all VFS implementations for unix-like operating +** systems. This routine, and the sqlite3_os_end() routine that follows, +** should be the only routines in this file that are visible from other +** files. +** +** This routine is called once during SQLite initialization and by a +** single thread. The memory allocation and mutex subsystems have not +** necessarily been initialized when this routine is called, and so they +** should not be used. +*/ +int sqlite3_os_init(void){ + /* + ** The following macro defines an initializer for an sqlite3_vfs object. + ** The name of the VFS is NAME. The pAppData is a pointer to a pointer + ** to the "finder" function. (pAppData is a pointer to a pointer because + ** silly C90 rules prohibit a void* from being cast to a function pointer + ** and so we have to go through the intermediate pointer to avoid problems + ** when compiling with -pedantic-errors on GCC.) + ** + ** The FINDER parameter to this macro is the name of the pointer to the + ** finder-function. The finder-function returns a pointer to the + ** sqlite_io_methods object that implements the desired locking + ** behaviors. See the division above that contains the IOMETHODS + ** macro for addition information on finder-functions. + ** + ** Most finders simply return a pointer to a fixed sqlite3_io_methods + ** object. But the "autolockIoFinder" available on MacOSX does a little + ** more than that; it looks at the filesystem type that hosts the + ** database file and tries to choose an locking method appropriate for + ** that filesystem time. + */ + #define UNIXVFS(VFSNAME, FINDER) { \ + 3, /* iVersion */ \ + sizeof(unixFile), /* szOsFile */ \ + MAX_PATHNAME, /* mxPathname */ \ + 0, /* pNext */ \ + VFSNAME, /* zName */ \ + (void*)&FINDER, /* pAppData */ \ + unixOpen, /* xOpen */ \ + unixDelete, /* xDelete */ \ + unixAccess, /* xAccess */ \ + unixFullPathname, /* xFullPathname */ \ + unixDlOpen, /* xDlOpen */ \ + unixDlError, /* xDlError */ \ + unixDlSym, /* xDlSym */ \ + unixDlClose, /* xDlClose */ \ + unixRandomness, /* xRandomness */ \ + unixSleep, /* xSleep */ \ + unixCurrentTime, /* xCurrentTime */ \ + unixGetLastError, /* xGetLastError */ \ + unixCurrentTimeInt64, /* xCurrentTimeInt64 */ \ + unixSetSystemCall, /* xSetSystemCall */ \ + unixGetSystemCall, /* xGetSystemCall */ \ + unixNextSystemCall, /* xNextSystemCall */ \ + } + + /* + ** All default VFSes for unix are contained in the following array. + ** + ** Note that the sqlite3_vfs.pNext field of the VFS object is modified + ** by the SQLite core when the VFS is registered. So the following + ** array cannot be const. + */ + static sqlite3_vfs aVfs[] = { +#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) + UNIXVFS("unix", autolockIoFinder ), +#elif OS_VXWORKS + UNIXVFS("unix", vxworksIoFinder ), +#else + UNIXVFS("unix", posixIoFinder ), +#endif + UNIXVFS("unix-none", nolockIoFinder ), + UNIXVFS("unix-dotfile", dotlockIoFinder ), + UNIXVFS("unix-excl", posixIoFinder ), +#if OS_VXWORKS + UNIXVFS("unix-namedsem", semIoFinder ), +#endif +#if SQLITE_ENABLE_LOCKING_STYLE || OS_VXWORKS + UNIXVFS("unix-posix", posixIoFinder ), +#endif +#if SQLITE_ENABLE_LOCKING_STYLE + UNIXVFS("unix-flock", flockIoFinder ), +#endif +#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) + UNIXVFS("unix-afp", afpIoFinder ), + UNIXVFS("unix-nfs", nfsIoFinder ), + UNIXVFS("unix-proxy", proxyIoFinder ), +#endif + }; + unsigned int i; /* Loop counter */ + + /* Double-check that the aSyscall[] array has been constructed + ** correctly. See ticket [bb3a86e890c8e96ab] */ + assert( ArraySize(aSyscall)==29 ); + + /* Register all VFSes defined in the aVfs[] array */ + for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){ +#ifdef SQLITE_DEFAULT_UNIX_VFS + sqlite3_vfs_register(&aVfs[i], + 0==strcmp(aVfs[i].zName,SQLITE_DEFAULT_UNIX_VFS)); +#else + sqlite3_vfs_register(&aVfs[i], i==0); +#endif + } +#ifdef SQLITE_OS_KV_OPTIONAL + sqlite3KvvfsInit(); +#endif + unixBigLock = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1); + +#ifndef SQLITE_OMIT_WAL + /* Validate lock assumptions */ + assert( SQLITE_SHM_NLOCK==8 ); /* Number of available locks */ + assert( UNIX_SHM_BASE==120 ); /* Start of locking area */ + /* Locks: + ** WRITE UNIX_SHM_BASE 120 + ** CKPT UNIX_SHM_BASE+1 121 + ** RECOVER UNIX_SHM_BASE+2 122 + ** READ-0 UNIX_SHM_BASE+3 123 + ** READ-1 UNIX_SHM_BASE+4 124 + ** READ-2 UNIX_SHM_BASE+5 125 + ** READ-3 UNIX_SHM_BASE+6 126 + ** READ-4 UNIX_SHM_BASE+7 127 + ** DMS UNIX_SHM_BASE+8 128 + */ + assert( UNIX_SHM_DMS==128 ); /* Byte offset of the deadman-switch */ +#endif + + /* Initialize temp file dir array. */ + unixTempFileInit(); + + return SQLITE_OK; +} + +/* +** Shutdown the operating system interface. +** +** Some operating systems might need to do some cleanup in this routine, +** to release dynamically allocated objects. But not on unix. +** This routine is a no-op for unix. +*/ +int sqlite3_os_end(void){ + unixBigLock = 0; + return SQLITE_OK; +} + +#endif /* SQLITE_OS_UNIX */ |