diff options
Diffstat (limited to 'js/src/ctypes/libffi/src/closures.c')
| -rw-r--r-- | js/src/ctypes/libffi/src/closures.c | 998 |
1 files changed, 998 insertions, 0 deletions
diff --git a/js/src/ctypes/libffi/src/closures.c b/js/src/ctypes/libffi/src/closures.c new file mode 100644 index 0000000000..5120021652 --- /dev/null +++ b/js/src/ctypes/libffi/src/closures.c @@ -0,0 +1,998 @@ +/* ----------------------------------------------------------------------- + closures.c - Copyright (c) 2019 Anthony Green + Copyright (c) 2007, 2009, 2010 Red Hat, Inc. + Copyright (C) 2007, 2009, 2010 Free Software Foundation, Inc + Copyright (c) 2011 Plausible Labs Cooperative, Inc. + + Code to allocate and deallocate memory for closures. + + Permission is hereby granted, free of charge, to any person obtaining + a copy of this software and associated documentation files (the + ``Software''), to deal in the Software without restriction, including + without limitation the rights to use, copy, modify, merge, publish, + distribute, sublicense, and/or sell copies of the Software, and to + permit persons to whom the Software is furnished to do so, subject to + the following conditions: + + The above copyright notice and this permission notice shall be included + in all copies or substantial portions of the Software. + + THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, + EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, + WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + DEALINGS IN THE SOFTWARE. + ----------------------------------------------------------------------- */ + +#if defined __linux__ && !defined _GNU_SOURCE +#define _GNU_SOURCE 1 +#endif + +#include <fficonfig.h> +#include <ffi.h> +#include <ffi_common.h> + +#ifdef __NetBSD__ +#include <sys/param.h> +#endif + +#if __NetBSD_Version__ - 0 >= 799007200 +/* NetBSD with PROT_MPROTECT */ +#include <sys/mman.h> + +#include <stddef.h> +#include <unistd.h> + +static const size_t overhead = + (sizeof(max_align_t) > sizeof(void *) + sizeof(size_t)) ? + sizeof(max_align_t) + : sizeof(void *) + sizeof(size_t); + +#define ADD_TO_POINTER(p, d) ((void *)((uintptr_t)(p) + (d))) + +void * +ffi_closure_alloc (size_t size, void **code) +{ + static size_t page_size; + size_t rounded_size; + void *codeseg, *dataseg; + int prot; + + /* Expect that PAX mprotect is active and a separate code mapping is necessary. */ + if (!code) + return NULL; + + /* Obtain system page size. */ + if (!page_size) + page_size = sysconf(_SC_PAGESIZE); + + /* Round allocation size up to the next page, keeping in mind the size field and pointer to code map. */ + rounded_size = (size + overhead + page_size - 1) & ~(page_size - 1); + + /* Primary mapping is RW, but request permission to switch to PROT_EXEC later. */ + prot = PROT_READ | PROT_WRITE | PROT_MPROTECT(PROT_EXEC); + dataseg = mmap(NULL, rounded_size, prot, MAP_ANON | MAP_PRIVATE, -1, 0); + if (dataseg == MAP_FAILED) + return NULL; + + /* Create secondary mapping and switch it to RX. */ + codeseg = mremap(dataseg, rounded_size, NULL, rounded_size, MAP_REMAPDUP); + if (codeseg == MAP_FAILED) { + munmap(dataseg, rounded_size); + return NULL; + } + if (mprotect(codeseg, rounded_size, PROT_READ | PROT_EXEC) == -1) { + munmap(codeseg, rounded_size); + munmap(dataseg, rounded_size); + return NULL; + } + + /* Remember allocation size and location of the secondary mapping for ffi_closure_free. */ + memcpy(dataseg, &rounded_size, sizeof(rounded_size)); + memcpy(ADD_TO_POINTER(dataseg, sizeof(size_t)), &codeseg, sizeof(void *)); + *code = ADD_TO_POINTER(codeseg, overhead); + return ADD_TO_POINTER(dataseg, overhead); +} + +void +ffi_closure_free (void *ptr) +{ + void *codeseg, *dataseg; + size_t rounded_size; + + dataseg = ADD_TO_POINTER(ptr, -overhead); + memcpy(&rounded_size, dataseg, sizeof(rounded_size)); + memcpy(&codeseg, ADD_TO_POINTER(dataseg, sizeof(size_t)), sizeof(void *)); + munmap(dataseg, rounded_size); + munmap(codeseg, rounded_size); +} +#else /* !NetBSD with PROT_MPROTECT */ + +#if !FFI_MMAP_EXEC_WRIT && !FFI_EXEC_TRAMPOLINE_TABLE +# if __linux__ && !defined(__ANDROID__) +/* This macro indicates it may be forbidden to map anonymous memory + with both write and execute permission. Code compiled when this + option is defined will attempt to map such pages once, but if it + fails, it falls back to creating a temporary file in a writable and + executable filesystem and mapping pages from it into separate + locations in the virtual memory space, one location writable and + another executable. */ +# define FFI_MMAP_EXEC_WRIT 1 +# define HAVE_MNTENT 1 +# endif +# if defined(X86_WIN32) || defined(X86_WIN64) || defined(_M_ARM64) || defined(__OS2__) +/* Windows systems may have Data Execution Protection (DEP) enabled, + which requires the use of VirtualMalloc/VirtualFree to alloc/free + executable memory. */ +# define FFI_MMAP_EXEC_WRIT 1 +# endif +#endif + +#if FFI_MMAP_EXEC_WRIT && !defined FFI_MMAP_EXEC_SELINUX +# if defined(__linux__) && !defined(__ANDROID__) +/* When defined to 1 check for SELinux and if SELinux is active, + don't attempt PROT_EXEC|PROT_WRITE mapping at all, as that + might cause audit messages. */ +# define FFI_MMAP_EXEC_SELINUX 1 +# endif +#endif + +#if FFI_CLOSURES + +#if FFI_EXEC_TRAMPOLINE_TABLE + +#ifdef __MACH__ + +#include <mach/mach.h> +#include <pthread.h> +#include <stdio.h> +#include <stdlib.h> + +extern void *ffi_closure_trampoline_table_page; + +typedef struct ffi_trampoline_table ffi_trampoline_table; +typedef struct ffi_trampoline_table_entry ffi_trampoline_table_entry; + +struct ffi_trampoline_table +{ + /* contiguous writable and executable pages */ + vm_address_t config_page; + vm_address_t trampoline_page; + + /* free list tracking */ + uint16_t free_count; + ffi_trampoline_table_entry *free_list; + ffi_trampoline_table_entry *free_list_pool; + + ffi_trampoline_table *prev; + ffi_trampoline_table *next; +}; + +struct ffi_trampoline_table_entry +{ + void *(*trampoline) (void); + ffi_trampoline_table_entry *next; +}; + +/* Total number of trampolines that fit in one trampoline table */ +#define FFI_TRAMPOLINE_COUNT (PAGE_MAX_SIZE / FFI_TRAMPOLINE_SIZE) + +static pthread_mutex_t ffi_trampoline_lock = PTHREAD_MUTEX_INITIALIZER; +static ffi_trampoline_table *ffi_trampoline_tables = NULL; + +static ffi_trampoline_table * +ffi_trampoline_table_alloc (void) +{ + ffi_trampoline_table *table; + vm_address_t config_page; + vm_address_t trampoline_page; + vm_address_t trampoline_page_template; + vm_prot_t cur_prot; + vm_prot_t max_prot; + kern_return_t kt; + uint16_t i; + + /* Allocate two pages -- a config page and a placeholder page */ + config_page = 0x0; + kt = vm_allocate (mach_task_self (), &config_page, PAGE_MAX_SIZE * 2, + VM_FLAGS_ANYWHERE); + if (kt != KERN_SUCCESS) + return NULL; + + /* Remap the trampoline table on top of the placeholder page */ + trampoline_page = config_page + PAGE_MAX_SIZE; + trampoline_page_template = (vm_address_t)&ffi_closure_trampoline_table_page; +#ifdef __arm__ + /* ffi_closure_trampoline_table_page can be thumb-biased on some ARM archs */ + trampoline_page_template &= ~1UL; +#endif + kt = vm_remap (mach_task_self (), &trampoline_page, PAGE_MAX_SIZE, 0x0, + VM_FLAGS_OVERWRITE, mach_task_self (), trampoline_page_template, + FALSE, &cur_prot, &max_prot, VM_INHERIT_SHARE); + if (kt != KERN_SUCCESS) + { + vm_deallocate (mach_task_self (), config_page, PAGE_MAX_SIZE * 2); + return NULL; + } + + /* We have valid trampoline and config pages */ + table = calloc (1, sizeof (ffi_trampoline_table)); + table->free_count = FFI_TRAMPOLINE_COUNT; + table->config_page = config_page; + table->trampoline_page = trampoline_page; + + /* Create and initialize the free list */ + table->free_list_pool = + calloc (FFI_TRAMPOLINE_COUNT, sizeof (ffi_trampoline_table_entry)); + + for (i = 0; i < table->free_count; i++) + { + ffi_trampoline_table_entry *entry = &table->free_list_pool[i]; + entry->trampoline = + (void *) (table->trampoline_page + (i * FFI_TRAMPOLINE_SIZE)); + + if (i < table->free_count - 1) + entry->next = &table->free_list_pool[i + 1]; + } + + table->free_list = table->free_list_pool; + + return table; +} + +static void +ffi_trampoline_table_free (ffi_trampoline_table *table) +{ + /* Remove from the list */ + if (table->prev != NULL) + table->prev->next = table->next; + + if (table->next != NULL) + table->next->prev = table->prev; + + /* Deallocate pages */ + vm_deallocate (mach_task_self (), table->config_page, PAGE_MAX_SIZE * 2); + + /* Deallocate free list */ + free (table->free_list_pool); + free (table); +} + +void * +ffi_closure_alloc (size_t size, void **code) +{ + /* Create the closure */ + ffi_closure *closure = malloc (size); + if (closure == NULL) + return NULL; + + pthread_mutex_lock (&ffi_trampoline_lock); + + /* Check for an active trampoline table with available entries. */ + ffi_trampoline_table *table = ffi_trampoline_tables; + if (table == NULL || table->free_list == NULL) + { + table = ffi_trampoline_table_alloc (); + if (table == NULL) + { + pthread_mutex_unlock (&ffi_trampoline_lock); + free (closure); + return NULL; + } + + /* Insert the new table at the top of the list */ + table->next = ffi_trampoline_tables; + if (table->next != NULL) + table->next->prev = table; + + ffi_trampoline_tables = table; + } + + /* Claim the free entry */ + ffi_trampoline_table_entry *entry = ffi_trampoline_tables->free_list; + ffi_trampoline_tables->free_list = entry->next; + ffi_trampoline_tables->free_count--; + entry->next = NULL; + + pthread_mutex_unlock (&ffi_trampoline_lock); + + /* Initialize the return values */ + *code = entry->trampoline; + closure->trampoline_table = table; + closure->trampoline_table_entry = entry; + + return closure; +} + +void +ffi_closure_free (void *ptr) +{ + ffi_closure *closure = ptr; + + pthread_mutex_lock (&ffi_trampoline_lock); + + /* Fetch the table and entry references */ + ffi_trampoline_table *table = closure->trampoline_table; + ffi_trampoline_table_entry *entry = closure->trampoline_table_entry; + + /* Return the entry to the free list */ + entry->next = table->free_list; + table->free_list = entry; + table->free_count++; + + /* If all trampolines within this table are free, and at least one other table exists, deallocate + * the table */ + if (table->free_count == FFI_TRAMPOLINE_COUNT + && ffi_trampoline_tables != table) + { + ffi_trampoline_table_free (table); + } + else if (ffi_trampoline_tables != table) + { + /* Otherwise, bump this table to the top of the list */ + table->prev = NULL; + table->next = ffi_trampoline_tables; + if (ffi_trampoline_tables != NULL) + ffi_trampoline_tables->prev = table; + + ffi_trampoline_tables = table; + } + + pthread_mutex_unlock (&ffi_trampoline_lock); + + /* Free the closure */ + free (closure); +} + +#endif + +// Per-target implementation; It's unclear what can reasonable be shared between two OS/architecture implementations. + +#elif FFI_MMAP_EXEC_WRIT /* !FFI_EXEC_TRAMPOLINE_TABLE */ + +#define USE_LOCKS 1 +#define USE_DL_PREFIX 1 +#ifdef __GNUC__ +#ifndef USE_BUILTIN_FFS +#define USE_BUILTIN_FFS 1 +#endif +#endif + +/* We need to use mmap, not sbrk. */ +#define HAVE_MORECORE 0 + +/* We could, in theory, support mremap, but it wouldn't buy us anything. */ +#define HAVE_MREMAP 0 + +/* We have no use for this, so save some code and data. */ +#define NO_MALLINFO 1 + +/* We need all allocations to be in regular segments, otherwise we + lose track of the corresponding code address. */ +#define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T + +/* Don't allocate more than a page unless needed. */ +#define DEFAULT_GRANULARITY ((size_t)malloc_getpagesize) + +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> +#ifndef _MSC_VER +#include <unistd.h> +#endif +#include <string.h> +#include <stdio.h> +#if !defined(X86_WIN32) && !defined(X86_WIN64) && !defined(_M_ARM64) +#ifdef HAVE_MNTENT +#include <mntent.h> +#endif /* HAVE_MNTENT */ +#include <sys/param.h> +#include <pthread.h> + +/* We don't want sys/mman.h to be included after we redefine mmap and + dlmunmap. */ +#include <sys/mman.h> +#define LACKS_SYS_MMAN_H 1 + +#if FFI_MMAP_EXEC_SELINUX +#include <sys/statfs.h> +#include <stdlib.h> + +static int selinux_enabled = -1; + +static int +selinux_enabled_check (void) +{ + struct statfs sfs; + FILE *f; + char *buf = NULL; + size_t len = 0; + + if (statfs ("/selinux", &sfs) >= 0 + && (unsigned int) sfs.f_type == 0xf97cff8cU) + return 1; + f = fopen ("/proc/mounts", "r"); + if (f == NULL) + return 0; + while (getline (&buf, &len, f) >= 0) + { + char *p = strchr (buf, ' '); + if (p == NULL) + break; + p = strchr (p + 1, ' '); + if (p == NULL) + break; + if (strncmp (p + 1, "selinuxfs ", 10) == 0) + { + free (buf); + fclose (f); + return 1; + } + } + free (buf); + fclose (f); + return 0; +} + +#define is_selinux_enabled() (selinux_enabled >= 0 ? selinux_enabled \ + : (selinux_enabled = selinux_enabled_check ())) + +#else + +#define is_selinux_enabled() 0 + +#endif /* !FFI_MMAP_EXEC_SELINUX */ + +/* On PaX enable kernels that have MPROTECT enable we can't use PROT_EXEC. */ +#ifdef FFI_MMAP_EXEC_EMUTRAMP_PAX +#include <stdlib.h> + +static int emutramp_enabled = -1; + +static int +emutramp_enabled_check (void) +{ + char *buf = NULL; + size_t len = 0; + FILE *f; + int ret; + f = fopen ("/proc/self/status", "r"); + if (f == NULL) + return 0; + ret = 0; + + while (getline (&buf, &len, f) != -1) + if (!strncmp (buf, "PaX:", 4)) + { + char emutramp; + if (sscanf (buf, "%*s %*c%c", &emutramp) == 1) + ret = (emutramp == 'E'); + break; + } + free (buf); + fclose (f); + return ret; +} + +#define is_emutramp_enabled() (emutramp_enabled >= 0 ? emutramp_enabled \ + : (emutramp_enabled = emutramp_enabled_check ())) +#endif /* FFI_MMAP_EXEC_EMUTRAMP_PAX */ + +#elif defined (__CYGWIN__) || defined(__INTERIX) + +#include <sys/mman.h> + +/* Cygwin is Linux-like, but not quite that Linux-like. */ +#define is_selinux_enabled() 0 + +#endif /* !defined(X86_WIN32) && !defined(X86_WIN64) */ + +#ifndef FFI_MMAP_EXEC_EMUTRAMP_PAX +#define is_emutramp_enabled() 0 +#endif /* FFI_MMAP_EXEC_EMUTRAMP_PAX */ + +/* Declare all functions defined in dlmalloc.c as static. */ +static void *dlmalloc(size_t); +static void dlfree(void*); +static void *dlcalloc(size_t, size_t) MAYBE_UNUSED; +static void *dlrealloc(void *, size_t) MAYBE_UNUSED; +static void *dlmemalign(size_t, size_t) MAYBE_UNUSED; +static void *dlvalloc(size_t) MAYBE_UNUSED; +static int dlmallopt(int, int) MAYBE_UNUSED; +static size_t dlmalloc_footprint(void) MAYBE_UNUSED; +static size_t dlmalloc_max_footprint(void) MAYBE_UNUSED; +static void** dlindependent_calloc(size_t, size_t, void**) MAYBE_UNUSED; +static void** dlindependent_comalloc(size_t, size_t*, void**) MAYBE_UNUSED; +static void *dlpvalloc(size_t) MAYBE_UNUSED; +static int dlmalloc_trim(size_t) MAYBE_UNUSED; +static size_t dlmalloc_usable_size(void*) MAYBE_UNUSED; +static void dlmalloc_stats(void) MAYBE_UNUSED; + +#if !(defined(X86_WIN32) || defined(X86_WIN64) || defined(_M_ARM64) || defined(__OS2__)) || defined (__CYGWIN__) || defined(__INTERIX) +/* Use these for mmap and munmap within dlmalloc.c. */ +static void *dlmmap(void *, size_t, int, int, int, off_t); +static int dlmunmap(void *, size_t); +#endif /* !(defined(X86_WIN32) || defined(X86_WIN64) || defined(__OS2__)) || defined (__CYGWIN__) || defined(__INTERIX) */ + +#define mmap dlmmap +#define munmap dlmunmap + +#include "dlmalloc.c" + +#undef mmap +#undef munmap + +#if !(defined(X86_WIN32) || defined(X86_WIN64) || defined(_M_ARM64) || defined(__OS2__)) || defined (__CYGWIN__) || defined(__INTERIX) + +/* A mutex used to synchronize access to *exec* variables in this file. */ +static pthread_mutex_t open_temp_exec_file_mutex = PTHREAD_MUTEX_INITIALIZER; + +/* A file descriptor of a temporary file from which we'll map + executable pages. */ +static int execfd = -1; + +/* The amount of space already allocated from the temporary file. */ +static size_t execsize = 0; + +/* Open a temporary file name, and immediately unlink it. */ +static int +open_temp_exec_file_name (char *name, int flags) +{ + int fd; + +#ifdef HAVE_MKOSTEMP + fd = mkostemp (name, flags); +#else + fd = mkstemp (name); +#endif + + if (fd != -1) + unlink (name); + + return fd; +} + +/* Open a temporary file in the named directory. */ +static int +open_temp_exec_file_dir (const char *dir) +{ + static const char suffix[] = "/ffiXXXXXX"; + int lendir, flags; + char *tempname; +#ifdef O_TMPFILE + int fd; +#endif + +#ifdef O_CLOEXEC + flags = O_CLOEXEC; +#else + flags = 0; +#endif + +#ifdef O_TMPFILE + fd = open (dir, flags | O_RDWR | O_EXCL | O_TMPFILE, 0700); + /* If the running system does not support the O_TMPFILE flag then retry without it. */ + if (fd != -1 || (errno != EINVAL && errno != EISDIR && errno != EOPNOTSUPP)) { + return fd; + } else { + errno = 0; + } +#endif + + lendir = (int) strlen (dir); + tempname = __builtin_alloca (lendir + sizeof (suffix)); + + if (!tempname) + return -1; + + memcpy (tempname, dir, lendir); + memcpy (tempname + lendir, suffix, sizeof (suffix)); + + return open_temp_exec_file_name (tempname, flags); +} + +/* Open a temporary file in the directory in the named environment + variable. */ +static int +open_temp_exec_file_env (const char *envvar) +{ + const char *value = getenv (envvar); + + if (!value) + return -1; + + return open_temp_exec_file_dir (value); +} + +#ifdef HAVE_MNTENT +/* Open a temporary file in an executable and writable mount point + listed in the mounts file. Subsequent calls with the same mounts + keep searching for mount points in the same file. Providing NULL + as the mounts file closes the file. */ +static int +open_temp_exec_file_mnt (const char *mounts) +{ + static const char *last_mounts; + static FILE *last_mntent; + + if (mounts != last_mounts) + { + if (last_mntent) + endmntent (last_mntent); + + last_mounts = mounts; + + if (mounts) + last_mntent = setmntent (mounts, "r"); + else + last_mntent = NULL; + } + + if (!last_mntent) + return -1; + + for (;;) + { + int fd; + struct mntent mnt; + char buf[MAXPATHLEN * 3]; + + if (getmntent_r (last_mntent, &mnt, buf, sizeof (buf)) == NULL) + return -1; + + if (hasmntopt (&mnt, "ro") + || hasmntopt (&mnt, "noexec") + || access (mnt.mnt_dir, W_OK)) + continue; + + fd = open_temp_exec_file_dir (mnt.mnt_dir); + + if (fd != -1) + return fd; + } +} +#endif /* HAVE_MNTENT */ + +/* Instructions to look for a location to hold a temporary file that + can be mapped in for execution. */ +static struct +{ + int (*func)(const char *); + const char *arg; + int repeat; +} open_temp_exec_file_opts[] = { + { open_temp_exec_file_env, "TMPDIR", 0 }, + { open_temp_exec_file_dir, "/tmp", 0 }, + { open_temp_exec_file_dir, "/var/tmp", 0 }, + { open_temp_exec_file_dir, "/dev/shm", 0 }, + { open_temp_exec_file_env, "HOME", 0 }, +#ifdef HAVE_MNTENT + { open_temp_exec_file_mnt, "/etc/mtab", 1 }, + { open_temp_exec_file_mnt, "/proc/mounts", 1 }, +#endif /* HAVE_MNTENT */ +}; + +/* Current index into open_temp_exec_file_opts. */ +static int open_temp_exec_file_opts_idx = 0; + +/* Reset a current multi-call func, then advances to the next entry. + If we're at the last, go back to the first and return nonzero, + otherwise return zero. */ +static int +open_temp_exec_file_opts_next (void) +{ + if (open_temp_exec_file_opts[open_temp_exec_file_opts_idx].repeat) + open_temp_exec_file_opts[open_temp_exec_file_opts_idx].func (NULL); + + open_temp_exec_file_opts_idx++; + if (open_temp_exec_file_opts_idx + == (sizeof (open_temp_exec_file_opts) + / sizeof (*open_temp_exec_file_opts))) + { + open_temp_exec_file_opts_idx = 0; + return 1; + } + + return 0; +} + +/* Return a file descriptor of a temporary zero-sized file in a + writable and executable filesystem. */ +static int +open_temp_exec_file (void) +{ + int fd; + + do + { + fd = open_temp_exec_file_opts[open_temp_exec_file_opts_idx].func + (open_temp_exec_file_opts[open_temp_exec_file_opts_idx].arg); + + if (!open_temp_exec_file_opts[open_temp_exec_file_opts_idx].repeat + || fd == -1) + { + if (open_temp_exec_file_opts_next ()) + break; + } + } + while (fd == -1); + + return fd; +} + +/* We need to allocate space in a file that will be backing a writable + mapping. Several problems exist with the usual approaches: + - fallocate() is Linux-only + - posix_fallocate() is not available on all platforms + - ftruncate() does not allocate space on filesystems with sparse files + Failure to allocate the space will cause SIGBUS to be thrown when + the mapping is subsequently written to. */ +static int +allocate_space (int fd, off_t offset, off_t len) +{ + static size_t page_size; + + /* Obtain system page size. */ + if (!page_size) + page_size = sysconf(_SC_PAGESIZE); + + unsigned char buf[page_size]; + memset (buf, 0, page_size); + + while (len > 0) + { + off_t to_write = (len < page_size) ? len : page_size; + if (write (fd, buf, to_write) < to_write) + return -1; + len -= to_write; + } + + return 0; +} + +/* Map in a chunk of memory from the temporary exec file into separate + locations in the virtual memory address space, one writable and one + executable. Returns the address of the writable portion, after + storing an offset to the corresponding executable portion at the + last word of the requested chunk. */ +static void * +dlmmap_locked (void *start, size_t length, int prot, int flags, off_t offset) +{ + void *ptr; + + if (execfd == -1) + { + open_temp_exec_file_opts_idx = 0; + retry_open: + execfd = open_temp_exec_file (); + if (execfd == -1) + return MFAIL; + } + + offset = execsize; + + if (allocate_space (execfd, offset, length)) + return MFAIL; + + flags &= ~(MAP_PRIVATE | MAP_ANONYMOUS); + flags |= MAP_SHARED; + + ptr = mmap (NULL, length, (prot & ~PROT_WRITE) | PROT_EXEC, + flags, execfd, offset); + if (ptr == MFAIL) + { + if (!offset) + { + close (execfd); + goto retry_open; + } + if (ftruncate (execfd, offset) != 0) + { + /* Fixme : Error logs can be added here. Returning an error for + * ftruncte() will not add any advantage as it is being + * validating in the error case. */ + } + + return MFAIL; + } + else if (!offset + && open_temp_exec_file_opts[open_temp_exec_file_opts_idx].repeat) + open_temp_exec_file_opts_next (); + + start = mmap (start, length, prot, flags, execfd, offset); + + if (start == MFAIL) + { + munmap (ptr, length); + if (ftruncate (execfd, offset) != 0) + { + /* Fixme : Error logs can be added here. Returning an error for + * ftruncte() will not add any advantage as it is being + * validating in the error case. */ + } + return start; + } + + mmap_exec_offset ((char *)start, length) = (char*)ptr - (char*)start; + + execsize += length; + + return start; +} + +/* Map in a writable and executable chunk of memory if possible. + Failing that, fall back to dlmmap_locked. */ +static void * +dlmmap (void *start, size_t length, int prot, + int flags, int fd, off_t offset) +{ + void *ptr; + + assert (start == NULL && length % malloc_getpagesize == 0 + && prot == (PROT_READ | PROT_WRITE) + && flags == (MAP_PRIVATE | MAP_ANONYMOUS) + && fd == -1 && offset == 0); + + if (execfd == -1 && is_emutramp_enabled ()) + { + ptr = mmap (start, length, prot & ~PROT_EXEC, flags, fd, offset); + return ptr; + } + + if (execfd == -1 && !is_selinux_enabled ()) + { + ptr = mmap (start, length, prot | PROT_EXEC, flags, fd, offset); + + if (ptr != MFAIL || (errno != EPERM && errno != EACCES)) + /* Cool, no need to mess with separate segments. */ + return ptr; + + /* If MREMAP_DUP is ever introduced and implemented, try mmap + with ((prot & ~PROT_WRITE) | PROT_EXEC) and mremap with + MREMAP_DUP and prot at this point. */ + } + + if (execsize == 0 || execfd == -1) + { + pthread_mutex_lock (&open_temp_exec_file_mutex); + ptr = dlmmap_locked (start, length, prot, flags, offset); + pthread_mutex_unlock (&open_temp_exec_file_mutex); + + return ptr; + } + + return dlmmap_locked (start, length, prot, flags, offset); +} + +/* Release memory at the given address, as well as the corresponding + executable page if it's separate. */ +static int +dlmunmap (void *start, size_t length) +{ + /* We don't bother decreasing execsize or truncating the file, since + we can't quite tell whether we're unmapping the end of the file. + We don't expect frequent deallocation anyway. If we did, we + could locate pages in the file by writing to the pages being + deallocated and checking that the file contents change. + Yuck. */ + msegmentptr seg = segment_holding (gm, start); + void *code; + + if (seg && (code = add_segment_exec_offset (start, seg)) != start) + { + int ret = munmap (code, length); + if (ret) + return ret; + } + + return munmap (start, length); +} + +#if FFI_CLOSURE_FREE_CODE +/* Return segment holding given code address. */ +static msegmentptr +segment_holding_code (mstate m, char* addr) +{ + msegmentptr sp = &m->seg; + for (;;) { + if (addr >= add_segment_exec_offset (sp->base, sp) + && addr < add_segment_exec_offset (sp->base, sp) + sp->size) + return sp; + if ((sp = sp->next) == 0) + return 0; + } +} +#endif + +#endif /* !(defined(X86_WIN32) || defined(X86_WIN64) || defined(_M_ARM64) || defined(__OS2__)) || defined (__CYGWIN__) || defined(__INTERIX) */ + +/* Allocate a chunk of memory with the given size. Returns a pointer + to the writable address, and sets *CODE to the executable + corresponding virtual address. */ +void * +ffi_closure_alloc (size_t size, void **code) +{ + void *ptr; + + if (!code) + return NULL; + + ptr = dlmalloc (size); + + if (ptr) + { + msegmentptr seg = segment_holding (gm, ptr); + + *code = add_segment_exec_offset (ptr, seg); + } + + return ptr; +} + +void * +ffi_data_to_code_pointer (void *data) +{ + msegmentptr seg = segment_holding (gm, data); + /* We expect closures to be allocated with ffi_closure_alloc(), in + which case seg will be non-NULL. However, some users take on the + burden of managing this memory themselves, in which case this + we'll just return data. */ + if (seg) + return add_segment_exec_offset (data, seg); + else + return data; +} + +/* Release a chunk of memory allocated with ffi_closure_alloc. If + FFI_CLOSURE_FREE_CODE is nonzero, the given address can be the + writable or the executable address given. Otherwise, only the + writable address can be provided here. */ +void +ffi_closure_free (void *ptr) +{ +#if FFI_CLOSURE_FREE_CODE + msegmentptr seg = segment_holding_code (gm, ptr); + + if (seg) + ptr = sub_segment_exec_offset (ptr, seg); +#endif + + dlfree (ptr); +} + +# else /* ! FFI_MMAP_EXEC_WRIT */ + +/* On many systems, memory returned by malloc is writable and + executable, so just use it. */ + +#include <stdlib.h> + +void * +ffi_closure_alloc (size_t size, void **code) +{ + if (!code) + return NULL; + + return *code = malloc (size); +} + +void +ffi_closure_free (void *ptr) +{ + free (ptr); +} + +void * +ffi_data_to_code_pointer (void *data) +{ + return data; +} + +# endif /* ! FFI_MMAP_EXEC_WRIT */ +#endif /* FFI_CLOSURES */ + +#endif /* NetBSD with PROT_MPROTECT */ |