diff options
Diffstat (limited to 'lib/wrappers/libffi/gcc/closures.c')
| -rw-r--r-- | lib/wrappers/libffi/gcc/closures.c | 627 |
1 files changed, 627 insertions, 0 deletions
diff --git a/lib/wrappers/libffi/gcc/closures.c b/lib/wrappers/libffi/gcc/closures.c new file mode 100644 index 000000000..c0ee06891 --- /dev/null +++ b/lib/wrappers/libffi/gcc/closures.c @@ -0,0 +1,627 @@ +/* ----------------------------------------------------------------------- + closures.c - 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 <ffi.h> +#include <ffi_common.h> + +#if !FFI_MMAP_EXEC_WRIT && !FFI_EXEC_TRAMPOLINE_TABLE +# if __gnu_linux__ +/* 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(__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 +# ifdef __linux__ +/* 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 + +// 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) + +#if FFI_CLOSURE_TEST +/* Don't release single pages, to avoid a worst-case scenario of + continuously allocating and releasing single pages, but release + pairs of pages, which should do just as well given that allocations + are likely to be small. */ +#define DEFAULT_TRIM_THRESHOLD ((size_t)malloc_getpagesize) +#endif + +#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) +#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) +{ + if (getenv ("FFI_DISABLE_EMUTRAMP") == NULL) + return 1; + else + return 0; +} + +#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 */ + +#if !(defined(X86_WIN32) || defined(X86_WIN64) || 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) */ + +#if !(defined(X86_WIN32) || defined(X86_WIN64) || 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 fd = mkstemp (name); + + 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 = strlen (dir); + char *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); +} + +/* 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 exexutable 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; +} + +/* 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 (ftruncate (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; + } + ftruncate (execfd, offset); + 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); + ftruncate (execfd, offset); + 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 FFI_CLOSURE_TEST + printf ("mapping in %zi\n", length); +#endif + + 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 FFI_CLOSURE_TEST + printf ("unmapping %zi\n", length); +#endif + + 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(__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) +{ + *code = malloc(size); + return *code; +#if 0 + 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; +#endif +} + +/* 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 0 +#if FFI_CLOSURE_FREE_CODE + msegmentptr seg = segment_holding_code(gm, ptr); + + if (seg) + ptr = sub_segment_exec_offset(ptr, seg); +#endif + + dlfree(ptr); +#endif + free(ptr); +} + + +#if FFI_CLOSURE_TEST +/* Do some internal sanity testing to make sure allocation and + deallocation of pages are working as intended. */ +int main () +{ + void *p[3]; +#define GET(idx, len) do { p[idx] = dlmalloc (len); printf ("allocated %zi for p[%i]\n", (len), (idx)); } while (0) +#define PUT(idx) do { printf ("freeing p[%i]\n", (idx)); dlfree (p[idx]); } while (0) + GET (0, malloc_getpagesize / 2); + GET (1, 2 * malloc_getpagesize - 64 * sizeof (void*)); + PUT (1); + GET (1, 2 * malloc_getpagesize); + GET (2, malloc_getpagesize / 2); + PUT (1); + PUT (0); + PUT (2); + return 0; +} +#endif /* FFI_CLOSURE_TEST */ +# 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); +} + +# endif /* ! FFI_MMAP_EXEC_WRIT */ +#endif /* FFI_CLOSURES */ |