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FILE5_38
src/magic.c
655 строк
15 KB
Christos Zoulas
From: Denys Vlasenko
07 май 2019, 05:27
07 май 2019, 05:27
190362a
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/* * Copyright (c) Christos Zoulas 2003. * All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice immediately at the beginning of the file, without modification, * this list of conditions, and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifdef WIN32 #include <windows.h> #include <shlwapi.h> #endif #include "file.h" #ifndef lint FILE_RCSID("@(#)$File: magic.c,v 1.111 2019/05/07 02:27:11 christos Exp $") #endif /* lint */ #include "magic.h" #include <stdlib.h> #include <unistd.h> #include <string.h> #ifdef QUICK #include <sys/mman.h> #endif #include <limits.h> /* for PIPE_BUF */ #if defined(HAVE_UTIMES) # include <sys/time.h> #elif defined(HAVE_UTIME) # if defined(HAVE_SYS_UTIME_H) # include <sys/utime.h> # elif defined(HAVE_UTIME_H) # include <utime.h> # endif #endif #ifdef HAVE_UNISTD_H #include <unistd.h> /* for read() */ #endif #ifndef PIPE_BUF /* Get the PIPE_BUF from pathconf */ #ifdef _PC_PIPE_BUF #define PIPE_BUF pathconf(".", _PC_PIPE_BUF) #else #define PIPE_BUF 512 #endif #endif private void close_and_restore(const struct magic_set *, const char *, int, const struct stat *); private int unreadable_info(struct magic_set *, mode_t, const char *); private const char* get_default_magic(void); #ifndef COMPILE_ONLY private const char *file_or_fd(struct magic_set *, const char *, int); #endif #ifndef STDIN_FILENO #define STDIN_FILENO 0 #endif #ifdef WIN32 /* HINSTANCE of this shared library. Needed for get_default_magic() */ static HINSTANCE _w32_dll_instance = NULL; static void _w32_append_path(char **hmagicpath, const char *fmt, ...) { char *tmppath; char *newpath; va_list ap; va_start(ap, fmt); if (vasprintf(&tmppath, fmt, ap) < 0) { va_end(ap); return; } va_end(ap); if (access(tmppath, R_OK) == -1) goto out; if (*hmagicpath == NULL) { *hmagicpath = tmppath; return; } if (asprintf(&newpath, "%s%c%s", *hmagicpath, PATHSEP, tmppath) < 0) goto out; free(*hmagicpath); free(tmppath); *hmagicpath = newpath; return; out: free(tmppath); } static void _w32_get_magic_relative_to(char **hmagicpath, HINSTANCE module) { static const char *trypaths[] = { "%s/share/misc/magic.mgc", "%s/magic.mgc", }; LPSTR dllpath; size_t sp; dllpath = calloc(MAX_PATH + 1, sizeof(*dllpath)); if (!GetModuleFileNameA(module, dllpath, MAX_PATH)) goto out; PathRemoveFileSpecA(dllpath); if (module) { char exepath[MAX_PATH]; GetModuleFileNameA(NULL, exepath, MAX_PATH); PathRemoveFileSpecA(exepath); if (stricmp(exepath, dllpath) == 0) goto out; } sp = strlen(dllpath); if (sp > 3 && stricmp(&dllpath[sp - 3], "bin") == 0) { _w32_append_path(hmagicpath, "%s/../share/misc/magic.mgc", dllpath); goto out; } for (sp = 0; sp < __arraycount(trypaths); sp++) _w32_append_path(hmagicpath, trypaths[sp], dllpath); out: free(dllpath); } /* Placate GCC by offering a sacrificial previous prototype */ BOOL WINAPI DllMain(HINSTANCE, DWORD, LPVOID); BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved __attribute__((__unused__))) { if (fdwReason == DLL_PROCESS_ATTACH) _w32_dll_instance = hinstDLL; return 1; } #endif private const char * get_default_magic(void) { static const char hmagic[] = "/.magic/magic.mgc"; static char *default_magic; char *home, *hmagicpath; #ifndef WIN32 struct stat st; if (default_magic) { free(default_magic); default_magic = NULL; } if ((home = getenv("HOME")) == NULL) return MAGIC; if (asprintf(&hmagicpath, "%s/.magic.mgc", home) < 0) return MAGIC; if (stat(hmagicpath, &st) == -1) { free(hmagicpath); if (asprintf(&hmagicpath, "%s/.magic", home) < 0) return MAGIC; if (stat(hmagicpath, &st) == -1) goto out; if (S_ISDIR(st.st_mode)) { free(hmagicpath); if (asprintf(&hmagicpath, "%s/%s", home, hmagic) < 0) return MAGIC; if (access(hmagicpath, R_OK) == -1) goto out; } } if (asprintf(&default_magic, "%s:%s", hmagicpath, MAGIC) < 0) goto out; free(hmagicpath); return default_magic; out: default_magic = NULL; free(hmagicpath); return MAGIC; #else hmagicpath = NULL; if (default_magic) { free(default_magic); default_magic = NULL; } /* First, try to get a magic file from user-application data */ if ((home = getenv("LOCALAPPDATA")) != NULL) _w32_append_path(&hmagicpath, "%s%s", home, hmagic); /* Second, try to get a magic file from the user profile data */ if ((home = getenv("USERPROFILE")) != NULL) _w32_append_path(&hmagicpath, "%s/Local Settings/Application Data%s", home, hmagic); /* Third, try to get a magic file from Common Files */ if ((home = getenv("COMMONPROGRAMFILES")) != NULL) _w32_append_path(&hmagicpath, "%s%s", home, hmagic); /* Fourth, try to get magic file relative to exe location */ _w32_get_magic_relative_to(&hmagicpath, NULL); /* Fifth, try to get magic file relative to dll location */ _w32_get_magic_relative_to(&hmagicpath, _w32_dll_instance); /* Avoid MAGIC constant - it likely points to a file within MSys tree */ default_magic = hmagicpath; return default_magic; #endif } public const char * magic_getpath(const char *magicfile, int action) { if (magicfile != NULL) return magicfile; magicfile = getenv("MAGIC"); if (magicfile != NULL) return magicfile; return action == FILE_LOAD ? get_default_magic() : MAGIC; } public struct magic_set * magic_open(int flags) { return file_ms_alloc(flags); } private int unreadable_info(struct magic_set *ms, mode_t md, const char *file) { if (file) { /* We cannot open it, but we were able to stat it. */ if (access(file, W_OK) == 0) if (file_printf(ms, "writable, ") == -1) return -1; if (access(file, X_OK) == 0) if (file_printf(ms, "executable, ") == -1) return -1; } if (S_ISREG(md)) if (file_printf(ms, "regular file, ") == -1) return -1; if (file_printf(ms, "no read permission") == -1) return -1; return 0; } public void magic_close(struct magic_set *ms) { if (ms == NULL) return; file_ms_free(ms); } /* * load a magic file */ public int magic_load(struct magic_set *ms, const char *magicfile) { if (ms == NULL) return -1; return file_apprentice(ms, magicfile, FILE_LOAD); } #ifndef COMPILE_ONLY /* * Install a set of compiled magic buffers. */ public int magic_load_buffers(struct magic_set *ms, void **bufs, size_t *sizes, size_t nbufs) { if (ms == NULL) return -1; return buffer_apprentice(ms, RCAST(struct magic **, bufs), sizes, nbufs); } #endif public int magic_compile(struct magic_set *ms, const char *magicfile) { if (ms == NULL) return -1; return file_apprentice(ms, magicfile, FILE_COMPILE); } public int magic_check(struct magic_set *ms, const char *magicfile) { if (ms == NULL) return -1; return file_apprentice(ms, magicfile, FILE_CHECK); } public int magic_list(struct magic_set *ms, const char *magicfile) { if (ms == NULL) return -1; return file_apprentice(ms, magicfile, FILE_LIST); } private void close_and_restore(const struct magic_set *ms, const char *name, int fd, const struct stat *sb) { if (fd == STDIN_FILENO || name == NULL) return; (void) close(fd); if ((ms->flags & MAGIC_PRESERVE_ATIME) != 0) { /* * Try to restore access, modification times if read it. * This is really *bad* because it will modify the status * time of the file... And of course this will affect * backup programs */ #ifdef HAVE_UTIMES struct timeval utsbuf[2]; (void)memset(utsbuf, 0, sizeof(utsbuf)); utsbuf[0].tv_sec = sb->st_atime; utsbuf[1].tv_sec = sb->st_mtime; (void) utimes(name, utsbuf); /* don't care if loses */ #elif defined(HAVE_UTIME_H) || defined(HAVE_SYS_UTIME_H) struct utimbuf utbuf; (void)memset(&utbuf, 0, sizeof(utbuf)); utbuf.actime = sb->st_atime; utbuf.modtime = sb->st_mtime; (void) utime(name, &utbuf); /* don't care if loses */ #endif } } #ifndef COMPILE_ONLY /* * find type of descriptor */ public const char * magic_descriptor(struct magic_set *ms, int fd) { if (ms == NULL) return NULL; return file_or_fd(ms, NULL, fd); } /* * find type of named file */ public const char * magic_file(struct magic_set *ms, const char *inname) { if (ms == NULL) return NULL; return file_or_fd(ms, inname, STDIN_FILENO); } private const char * file_or_fd(struct magic_set *ms, const char *inname, int fd) { int rv = -1; unsigned char *buf; struct stat sb; ssize_t nbytes = 0; /* number of bytes read from a datafile */ int ispipe = 0; int okstat = 0; off_t pos = CAST(off_t, -1); if (file_reset(ms, 1) == -1) goto out; /* * one extra for terminating '\0', and * some overlapping space for matches near EOF */ #define SLOP (1 + sizeof(union VALUETYPE)) if ((buf = CAST(unsigned char *, malloc(ms->bytes_max + SLOP))) == NULL) return NULL; switch (file_fsmagic(ms, inname, &sb)) { case -1: /* error */ goto done; case 0: /* nothing found */ break; default: /* matched it and printed type */ rv = 0; goto done; } #ifdef WIN32 /* Place stdin in binary mode, so EOF (Ctrl+Z) doesn't stop early. */ if (fd == STDIN_FILENO) _setmode(STDIN_FILENO, O_BINARY); #endif if (inname != NULL) { int flags = O_RDONLY|O_BINARY|O_NONBLOCK; errno = 0; if ((fd = open(inname, flags)) < 0) { okstat = stat(inname, &sb) == 0; if (okstat && S_ISFIFO(sb.st_mode)) ispipe = 1; #ifdef WIN32 /* * Can't stat, can't open. It may have been opened in * fsmagic, so if the user doesn't have read permission, * allow it to say so; otherwise an error was probably * displayed in fsmagic. */ if (!okstat && errno == EACCES) { sb.st_mode = S_IFBLK; okstat = 1; } #endif if (okstat && unreadable_info(ms, sb.st_mode, inname) == -1) goto done; rv = 0; goto done; } } if (fd != -1) { if (!okstat) okstat = fstat(fd, &sb) == 0; if (okstat && S_ISFIFO(sb.st_mode)) ispipe = 1; if (inname == NULL) pos = lseek(fd, CAST(off_t, 0), SEEK_CUR); } /* * try looking at the first ms->bytes_max bytes */ if (ispipe) { if (fd != -1) { ssize_t r = 0; while ((r = sread(fd, RCAST(void *, &buf[nbytes]), CAST(size_t, ms->bytes_max - nbytes), 1)) > 0) { nbytes += r; if (r < PIPE_BUF) break; } } if (nbytes == 0 && inname) { /* We can not read it, but we were able to stat it. */ if (unreadable_info(ms, sb.st_mode, inname) == -1) goto done; rv = 0; goto done; } } else if (fd != -1) { /* Windows refuses to read from a big console buffer. */ size_t howmany = #if defined(WIN32) _isatty(fd) ? 8 * 1024 : #endif ms->bytes_max; if ((nbytes = read(fd, RCAST(void *, buf), howmany)) == -1) { if (inname == NULL && fd != STDIN_FILENO) file_error(ms, errno, "cannot read fd %d", fd); else file_error(ms, errno, "cannot read `%s'", inname == NULL ? "/dev/stdin" : inname); goto done; } } (void)memset(buf + nbytes, 0, SLOP); /* NUL terminate */ if (file_buffer(ms, fd, okstat ? &sb : NULL, inname, buf, CAST(size_t, nbytes)) == -1) goto done; rv = 0; done: free(buf); if (fd != -1) { if (pos != CAST(off_t, -1)) (void)lseek(fd, pos, SEEK_SET); close_and_restore(ms, inname, fd, &sb); } out: return rv == 0 ? file_getbuffer(ms) : NULL; } public const char * magic_buffer(struct magic_set *ms, const void *buf, size_t nb) { if (ms == NULL) return NULL; if (file_reset(ms, 1) == -1) return NULL; /* * The main work is done here! * We have the file name and/or the data buffer to be identified. */ if (file_buffer(ms, -1, NULL, NULL, buf, nb) == -1) { return NULL; } return file_getbuffer(ms); } #endif public const char * magic_error(struct magic_set *ms) { if (ms == NULL) return "Magic database is not open"; return (ms->event_flags & EVENT_HAD_ERR) ? ms->o.buf : NULL; } public int magic_errno(struct magic_set *ms) { if (ms == NULL) return EINVAL; return (ms->event_flags & EVENT_HAD_ERR) ? ms->error : 0; } public int magic_getflags(struct magic_set *ms) { if (ms == NULL) return -1; return ms->flags; } public int magic_setflags(struct magic_set *ms, int flags) { if (ms == NULL) return -1; #if !defined(HAVE_UTIME) && !defined(HAVE_UTIMES) if (flags & MAGIC_PRESERVE_ATIME) return -1; #endif ms->flags = flags; return 0; } public int magic_version(void) { return MAGIC_VERSION; } public int magic_setparam(struct magic_set *ms, int param, const void *val) { if (ms == NULL) return -1; switch (param) { case MAGIC_PARAM_INDIR_MAX: ms->indir_max = CAST(uint16_t, *CAST(const size_t *, val)); return 0; case MAGIC_PARAM_NAME_MAX: ms->name_max = CAST(uint16_t, *CAST(const size_t *, val)); return 0; case MAGIC_PARAM_ELF_PHNUM_MAX: ms->elf_phnum_max = CAST(uint16_t, *CAST(const size_t *, val)); return 0; case MAGIC_PARAM_ELF_SHNUM_MAX: ms->elf_shnum_max = CAST(uint16_t, *CAST(const size_t *, val)); return 0; case MAGIC_PARAM_ELF_NOTES_MAX: ms->elf_notes_max = CAST(uint16_t, *CAST(const size_t *, val)); return 0; case MAGIC_PARAM_REGEX_MAX: ms->regex_max = CAST(uint16_t, *CAST(const size_t *, val)); return 0; case MAGIC_PARAM_BYTES_MAX: ms->bytes_max = *CAST(const size_t *, val); return 0; default: errno = EINVAL; return -1; } } public int magic_getparam(struct magic_set *ms, int param, void *val) { if (ms == NULL) return -1; switch (param) { case MAGIC_PARAM_INDIR_MAX: *CAST(size_t *, val) = ms->indir_max; return 0; case MAGIC_PARAM_NAME_MAX: *CAST(size_t *, val) = ms->name_max; return 0; case MAGIC_PARAM_ELF_PHNUM_MAX: *CAST(size_t *, val) = ms->elf_phnum_max; return 0; case MAGIC_PARAM_ELF_SHNUM_MAX: *CAST(size_t *, val) = ms->elf_shnum_max; return 0; case MAGIC_PARAM_ELF_NOTES_MAX: *CAST(size_t *, val) = ms->elf_notes_max; return 0; case MAGIC_PARAM_REGEX_MAX: *CAST(size_t *, val) = ms->regex_max; return 0; case MAGIC_PARAM_BYTES_MAX: *CAST(size_t *, val) = ms->bytes_max; return 0; default: errno = EINVAL; return -1; } }