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Diffstat (limited to '')
| -rw-r--r-- | lib/fcntl.c | 629 |
1 files changed, 629 insertions, 0 deletions
diff --git a/lib/fcntl.c b/lib/fcntl.c new file mode 100644 index 0000000..f9753c4 --- /dev/null +++ b/lib/fcntl.c @@ -0,0 +1,629 @@ +/* Provide file descriptor control. + + Copyright (C) 2009-2022 Free Software Foundation, Inc. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Written by Eric Blake <ebb9@byu.net>. */ + +#include <config.h> + +/* Specification. */ +#include <fcntl.h> + +#include <errno.h> +#include <limits.h> +#include <stdarg.h> +#include <stdlib.h> +#include <unistd.h> + +#ifdef __KLIBC__ +# define INCL_DOS +# include <os2.h> +#endif + +#if defined _WIN32 && ! defined __CYGWIN__ +/* Get declarations of the native Windows API functions. */ +# define WIN32_LEAN_AND_MEAN +# include <windows.h> + +/* Get _get_osfhandle. */ +# if GNULIB_MSVC_NOTHROW +# include "msvc-nothrow.h" +# else +# include <io.h> +# endif + +/* Upper bound on getdtablesize(). See lib/getdtablesize.c. */ +# define OPEN_MAX_MAX 0x10000 + +/* Duplicate OLDFD into the first available slot of at least NEWFD, + which must be positive, with FLAGS determining whether the duplicate + will be inheritable. */ +static int +dupfd (int oldfd, int newfd, int flags) +{ + /* Mingw has no way to create an arbitrary fd. Iterate until all + file descriptors less than newfd are filled up. */ + HANDLE curr_process = GetCurrentProcess (); + HANDLE old_handle = (HANDLE) _get_osfhandle (oldfd); + unsigned char fds_to_close[OPEN_MAX_MAX / CHAR_BIT]; + unsigned int fds_to_close_bound = 0; + int result; + BOOL inherit = flags & O_CLOEXEC ? FALSE : TRUE; + int mode; + + if (newfd < 0 || getdtablesize () <= newfd) + { + errno = EINVAL; + return -1; + } + if (old_handle == INVALID_HANDLE_VALUE + || (mode = _setmode (oldfd, O_BINARY)) == -1) + { + /* oldfd is not open, or is an unassigned standard file + descriptor. */ + errno = EBADF; + return -1; + } + _setmode (oldfd, mode); + flags |= mode; + + for (;;) + { + HANDLE new_handle; + int duplicated_fd; + unsigned int index; + + if (!DuplicateHandle (curr_process, /* SourceProcessHandle */ + old_handle, /* SourceHandle */ + curr_process, /* TargetProcessHandle */ + (PHANDLE) &new_handle, /* TargetHandle */ + (DWORD) 0, /* DesiredAccess */ + inherit, /* InheritHandle */ + DUPLICATE_SAME_ACCESS)) /* Options */ + { + switch (GetLastError ()) + { + case ERROR_TOO_MANY_OPEN_FILES: + errno = EMFILE; + break; + case ERROR_INVALID_HANDLE: + case ERROR_INVALID_TARGET_HANDLE: + case ERROR_DIRECT_ACCESS_HANDLE: + errno = EBADF; + break; + case ERROR_INVALID_PARAMETER: + case ERROR_INVALID_FUNCTION: + case ERROR_INVALID_ACCESS: + errno = EINVAL; + break; + default: + errno = EACCES; + break; + } + result = -1; + break; + } + duplicated_fd = _open_osfhandle ((intptr_t) new_handle, flags); + if (duplicated_fd < 0) + { + CloseHandle (new_handle); + result = -1; + break; + } + if (newfd <= duplicated_fd) + { + result = duplicated_fd; + break; + } + + /* Set the bit duplicated_fd in fds_to_close[]. */ + index = (unsigned int) duplicated_fd / CHAR_BIT; + if (fds_to_close_bound <= index) + { + if (sizeof fds_to_close <= index) + /* Need to increase OPEN_MAX_MAX. */ + abort (); + memset (fds_to_close + fds_to_close_bound, '\0', + index + 1 - fds_to_close_bound); + fds_to_close_bound = index + 1; + } + fds_to_close[index] |= 1 << ((unsigned int) duplicated_fd % CHAR_BIT); + } + + /* Close the previous fds that turned out to be too small. */ + { + int saved_errno = errno; + unsigned int duplicated_fd; + + for (duplicated_fd = 0; + duplicated_fd < fds_to_close_bound * CHAR_BIT; + duplicated_fd++) + if ((fds_to_close[duplicated_fd / CHAR_BIT] + >> (duplicated_fd % CHAR_BIT)) + & 1) + close (duplicated_fd); + + errno = saved_errno; + } + +# if REPLACE_FCHDIR + if (0 <= result) + result = _gl_register_dup (oldfd, result); +# endif + return result; +} +#endif /* W32 */ + +/* Forward declarations, because we '#undef fcntl' in the middle of this + compilation unit. */ +/* Our implementation of fcntl (fd, F_DUPFD, target). */ +static int rpl_fcntl_DUPFD (int fd, int target); +/* Our implementation of fcntl (fd, F_DUPFD_CLOEXEC, target). */ +static int rpl_fcntl_DUPFD_CLOEXEC (int fd, int target); +#ifdef __KLIBC__ +/* Adds support for fcntl on directories. */ +static int klibc_fcntl (int fd, int action, /* arg */...); +#endif + + +/* Perform the specified ACTION on the file descriptor FD, possibly + using the argument ARG further described below. This replacement + handles the following actions, and forwards all others on to the + native fcntl. An unrecognized ACTION returns -1 with errno set to + EINVAL. + + F_DUPFD - duplicate FD, with int ARG being the minimum target fd. + If successful, return the duplicate, which will be inheritable; + otherwise return -1 and set errno. + + F_DUPFD_CLOEXEC - duplicate FD, with int ARG being the minimum + target fd. If successful, return the duplicate, which will not be + inheritable; otherwise return -1 and set errno. + + F_GETFD - ARG need not be present. If successful, return a + non-negative value containing the descriptor flags of FD (only + FD_CLOEXEC is portable, but other flags may be present); otherwise + return -1 and set errno. */ + +int +fcntl (int fd, int action, /* arg */...) +#undef fcntl +#ifdef __KLIBC__ +# define fcntl klibc_fcntl +#endif +{ + va_list arg; + int result = -1; + va_start (arg, action); + switch (action) + { + case F_DUPFD: + { + int target = va_arg (arg, int); + result = rpl_fcntl_DUPFD (fd, target); + break; + } + + case F_DUPFD_CLOEXEC: + { + int target = va_arg (arg, int); + result = rpl_fcntl_DUPFD_CLOEXEC (fd, target); + break; + } + +#if !HAVE_FCNTL + case F_GETFD: + { +# if defined _WIN32 && ! defined __CYGWIN__ + HANDLE handle = (HANDLE) _get_osfhandle (fd); + DWORD flags; + if (handle == INVALID_HANDLE_VALUE + || GetHandleInformation (handle, &flags) == 0) + errno = EBADF; + else + result = (flags & HANDLE_FLAG_INHERIT) ? 0 : FD_CLOEXEC; +# else /* !W32 */ + /* Use dup2 to reject invalid file descriptors. No way to + access this information, so punt. */ + if (0 <= dup2 (fd, fd)) + result = 0; +# endif /* !W32 */ + break; + } /* F_GETFD */ +#endif /* !HAVE_FCNTL */ + + /* Implementing F_SETFD on mingw is not trivial - there is no + API for changing the O_NOINHERIT bit on an fd, and merely + changing the HANDLE_FLAG_INHERIT bit on the underlying handle + can lead to odd state. It may be possible by duplicating the + handle, using _open_osfhandle with the right flags, then + using dup2 to move the duplicate onto the original, but that + is not supported for now. */ + + default: + { +#if HAVE_FCNTL + switch (action) + { + #ifdef F_BARRIERFSYNC /* macOS */ + case F_BARRIERFSYNC: + #endif + #ifdef F_CHKCLEAN /* macOS */ + case F_CHKCLEAN: + #endif + #ifdef F_CLOSEM /* NetBSD, HP-UX */ + case F_CLOSEM: + #endif + #ifdef F_FLUSH_DATA /* macOS */ + case F_FLUSH_DATA: + #endif + #ifdef F_FREEZE_FS /* macOS */ + case F_FREEZE_FS: + #endif + #ifdef F_FULLFSYNC /* macOS */ + case F_FULLFSYNC: + #endif + #ifdef F_GETCONFINED /* macOS */ + case F_GETCONFINED: + #endif + #ifdef F_GETDEFAULTPROTLEVEL /* macOS */ + case F_GETDEFAULTPROTLEVEL: + #endif + #ifdef F_GETFD /* POSIX */ + case F_GETFD: + #endif + #ifdef F_GETFL /* POSIX */ + case F_GETFL: + #endif + #ifdef F_GETLEASE /* Linux */ + case F_GETLEASE: + #endif + #ifdef F_GETNOSIGPIPE /* macOS */ + case F_GETNOSIGPIPE: + #endif + #ifdef F_GETOWN /* POSIX */ + case F_GETOWN: + #endif + #ifdef F_GETPIPE_SZ /* Linux */ + case F_GETPIPE_SZ: + #endif + #ifdef F_GETPROTECTIONCLASS /* macOS */ + case F_GETPROTECTIONCLASS: + #endif + #ifdef F_GETPROTECTIONLEVEL /* macOS */ + case F_GETPROTECTIONLEVEL: + #endif + #ifdef F_GET_SEALS /* Linux */ + case F_GET_SEALS: + #endif + #ifdef F_GETSIG /* Linux */ + case F_GETSIG: + #endif + #ifdef F_MAXFD /* NetBSD */ + case F_MAXFD: + #endif + #ifdef F_RECYCLE /* macOS */ + case F_RECYCLE: + #endif + #ifdef F_SETFIFOENH /* HP-UX */ + case F_SETFIFOENH: + #endif + #ifdef F_THAW_FS /* macOS */ + case F_THAW_FS: + #endif + /* These actions take no argument. */ + result = fcntl (fd, action); + break; + + #ifdef F_ADD_SEALS /* Linux */ + case F_ADD_SEALS: + #endif + #ifdef F_BADFD /* Solaris */ + case F_BADFD: + #endif + #ifdef F_CHECK_OPENEVT /* macOS */ + case F_CHECK_OPENEVT: + #endif + #ifdef F_DUP2FD /* FreeBSD, AIX, Solaris */ + case F_DUP2FD: + #endif + #ifdef F_DUP2FD_CLOEXEC /* FreeBSD, Solaris */ + case F_DUP2FD_CLOEXEC: + #endif + #ifdef F_DUP2FD_CLOFORK /* Solaris */ + case F_DUP2FD_CLOFORK: + #endif + #ifdef F_DUPFD /* POSIX */ + case F_DUPFD: + #endif + #ifdef F_DUPFD_CLOEXEC /* POSIX */ + case F_DUPFD_CLOEXEC: + #endif + #ifdef F_DUPFD_CLOFORK /* Solaris */ + case F_DUPFD_CLOFORK: + #endif + #ifdef F_GETXFL /* Solaris */ + case F_GETXFL: + #endif + #ifdef F_GLOBAL_NOCACHE /* macOS */ + case F_GLOBAL_NOCACHE: + #endif + #ifdef F_MAKECOMPRESSED /* macOS */ + case F_MAKECOMPRESSED: + #endif + #ifdef F_MOVEDATAEXTENTS /* macOS */ + case F_MOVEDATAEXTENTS: + #endif + #ifdef F_NOCACHE /* macOS */ + case F_NOCACHE: + #endif + #ifdef F_NODIRECT /* macOS */ + case F_NODIRECT: + #endif + #ifdef F_NOTIFY /* Linux */ + case F_NOTIFY: + #endif + #ifdef F_OPLKACK /* IRIX */ + case F_OPLKACK: + #endif + #ifdef F_OPLKREG /* IRIX */ + case F_OPLKREG: + #endif + #ifdef F_RDAHEAD /* macOS */ + case F_RDAHEAD: + #endif + #ifdef F_SETBACKINGSTORE /* macOS */ + case F_SETBACKINGSTORE: + #endif + #ifdef F_SETCONFINED /* macOS */ + case F_SETCONFINED: + #endif + #ifdef F_SETFD /* POSIX */ + case F_SETFD: + #endif + #ifdef F_SETFL /* POSIX */ + case F_SETFL: + #endif + #ifdef F_SETLEASE /* Linux */ + case F_SETLEASE: + #endif + #ifdef F_SETNOSIGPIPE /* macOS */ + case F_SETNOSIGPIPE: + #endif + #ifdef F_SETOWN /* POSIX */ + case F_SETOWN: + #endif + #ifdef F_SETPIPE_SZ /* Linux */ + case F_SETPIPE_SZ: + #endif + #ifdef F_SETPROTECTIONCLASS /* macOS */ + case F_SETPROTECTIONCLASS: + #endif + #ifdef F_SETSIG /* Linux */ + case F_SETSIG: + #endif + #ifdef F_SINGLE_WRITER /* macOS */ + case F_SINGLE_WRITER: + #endif + /* These actions take an 'int' argument. */ + { + int x = va_arg (arg, int); + result = fcntl (fd, action, x); + } + break; + + default: + /* Other actions take a pointer argument. */ + { + void *p = va_arg (arg, void *); + result = fcntl (fd, action, p); + } + break; + } +#else + errno = EINVAL; +#endif + break; + } + } + va_end (arg); + return result; +} + +static int +rpl_fcntl_DUPFD (int fd, int target) +{ + int result; +#if !HAVE_FCNTL + result = dupfd (fd, target, 0); +#elif FCNTL_DUPFD_BUGGY || REPLACE_FCHDIR + /* Detect invalid target; needed for cygwin 1.5.x. */ + if (target < 0 || getdtablesize () <= target) + { + result = -1; + errno = EINVAL; + } + else + { + /* Haiku alpha 2 loses fd flags on original. */ + int flags = fcntl (fd, F_GETFD); + if (flags < 0) + result = -1; + else + { + result = fcntl (fd, F_DUPFD, target); + if (0 <= result && fcntl (fd, F_SETFD, flags) == -1) + { + int saved_errno = errno; + close (result); + result = -1; + errno = saved_errno; + } +# if REPLACE_FCHDIR + if (0 <= result) + result = _gl_register_dup (fd, result); +# endif + } + } +#else + result = fcntl (fd, F_DUPFD, target); +#endif + return result; +} + +static int +rpl_fcntl_DUPFD_CLOEXEC (int fd, int target) +{ + int result; +#if !HAVE_FCNTL + result = dupfd (fd, target, O_CLOEXEC); +#else /* HAVE_FCNTL */ +# if defined __NetBSD__ || defined __HAIKU__ + /* On NetBSD 9.0, the system fcntl (fd, F_DUPFD_CLOEXEC, target) + has only the same effect as fcntl (fd, F_DUPFD, target). */ + /* On Haiku, the system fcntl (fd, F_DUPFD_CLOEXEC, target) sets + the FD_CLOEXEC flag on fd, not on target. Therefore avoid the + system fcntl in this case. */ +# define have_dupfd_cloexec -1 +# else + /* Try the system call first, if the headers claim it exists + (that is, if GNULIB_defined_F_DUPFD_CLOEXEC is 0), since we + may be running with a glibc that has the macro but with an + older kernel that does not support it. Cache the + information on whether the system call really works, but + avoid caching failure if the corresponding F_DUPFD fails + for any reason. 0 = unknown, 1 = yes, -1 = no. */ + static int have_dupfd_cloexec = GNULIB_defined_F_DUPFD_CLOEXEC ? -1 : 0; + if (0 <= have_dupfd_cloexec) + { + result = fcntl (fd, F_DUPFD_CLOEXEC, target); + if (0 <= result || errno != EINVAL) + { + have_dupfd_cloexec = 1; +# if REPLACE_FCHDIR + if (0 <= result) + result = _gl_register_dup (fd, result); +# endif + } + else + { + result = rpl_fcntl_DUPFD (fd, target); + if (result >= 0) + have_dupfd_cloexec = -1; + } + } + else +# endif + result = rpl_fcntl_DUPFD (fd, target); + if (0 <= result && have_dupfd_cloexec == -1) + { + int flags = fcntl (result, F_GETFD); + if (flags < 0 || fcntl (result, F_SETFD, flags | FD_CLOEXEC) == -1) + { + int saved_errno = errno; + close (result); + errno = saved_errno; + result = -1; + } + } +#endif /* HAVE_FCNTL */ + return result; +} + +#undef fcntl + +#ifdef __KLIBC__ + +static int +klibc_fcntl (int fd, int action, /* arg */...) +{ + va_list arg_ptr; + int arg; + struct stat sbuf; + int result; + + va_start (arg_ptr, action); + arg = va_arg (arg_ptr, int); + result = fcntl (fd, action, arg); + /* EPERM for F_DUPFD, ENOTSUP for others */ + if (result == -1 && (errno == EPERM || errno == ENOTSUP) + && !fstat (fd, &sbuf) && S_ISDIR (sbuf.st_mode)) + { + ULONG ulMode; + + switch (action) + { + case F_DUPFD: + /* Find available fd */ + while (fcntl (arg, F_GETFL) != -1 || errno != EBADF) + arg++; + + result = dup2 (fd, arg); + break; + + /* Using underlying APIs is right ? */ + case F_GETFD: + if (DosQueryFHState (fd, &ulMode)) + break; + + result = (ulMode & OPEN_FLAGS_NOINHERIT) ? FD_CLOEXEC : 0; + break; + + case F_SETFD: + if (arg & ~FD_CLOEXEC) + break; + + if (DosQueryFHState (fd, &ulMode)) + break; + + if (arg & FD_CLOEXEC) + ulMode |= OPEN_FLAGS_NOINHERIT; + else + ulMode &= ~OPEN_FLAGS_NOINHERIT; + + /* Filter supported flags. */ + ulMode &= (OPEN_FLAGS_WRITE_THROUGH | OPEN_FLAGS_FAIL_ON_ERROR + | OPEN_FLAGS_NO_CACHE | OPEN_FLAGS_NOINHERIT); + + if (DosSetFHState (fd, ulMode)) + break; + + result = 0; + break; + + case F_GETFL: + result = 0; + break; + + case F_SETFL: + if (arg != 0) + break; + + result = 0; + break; + + default: + errno = EINVAL; + break; + } + } + + va_end (arg_ptr); + + return result; +} + +#endif |