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-rw-r--r--src/magic.c686
1 files changed, 686 insertions, 0 deletions
diff --git a/src/magic.c b/src/magic.c
new file mode 100644
index 0000000..052f997
--- /dev/null
+++ b/src/magic.c
@@ -0,0 +1,686 @@
+/*
+ * 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 1.121 2023/02/09 17:45:19 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
+
+file_private void close_and_restore(const struct magic_set *, const char *, int,
+ const struct stat *);
+file_private int unreadable_info(struct magic_set *, mode_t, const char *);
+file_private const char* get_default_magic(void);
+#ifndef COMPILE_ONLY
+file_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);
+}
+
+#ifndef BUILD_AS_WINDOWS_STATIC_LIBARAY
+/* 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
+#endif
+
+file_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;
+ }
+
+ /* Before anything else, try to get a magic file from user HOME */
+ if ((home = getenv("HOME")) != NULL)
+ _w32_append_path(&hmagicpath, "%s%s", home, hmagic);
+
+ /* 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
+}
+
+file_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;
+}
+
+file_public struct magic_set *
+magic_open(int flags)
+{
+ return file_ms_alloc(flags);
+}
+
+file_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;
+#ifndef WIN32
+ if (access(file, X_OK) == 0)
+ if (file_printf(ms, "executable, ") == -1)
+ return -1;
+#else
+ /* X_OK doesn't work well on MS-Windows */
+ {
+ const char *p = strrchr(file, '.');
+ if (p && (stricmp(p, ".exe")
+ || stricmp(p, ".dll")
+ || stricmp(p, ".bat")
+ || stricmp(p, ".cmd")))
+ if (file_printf(ms, "writable, ") == -1)
+ return -1;
+ }
+#endif
+ }
+ 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;
+}
+
+file_public void
+magic_close(struct magic_set *ms)
+{
+ if (ms == NULL)
+ return;
+ file_ms_free(ms);
+}
+
+/*
+ * load a magic file
+ */
+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.
+ */
+file_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
+
+file_public int
+magic_compile(struct magic_set *ms, const char *magicfile)
+{
+ if (ms == NULL)
+ return -1;
+ return file_apprentice(ms, magicfile, FILE_COMPILE);
+}
+
+file_public int
+magic_check(struct magic_set *ms, const char *magicfile)
+{
+ if (ms == NULL)
+ return -1;
+ return file_apprentice(ms, magicfile, FILE_CHECK);
+}
+
+file_public int
+magic_list(struct magic_set *ms, const char *magicfile)
+{
+ if (ms == NULL)
+ return -1;
+ return file_apprentice(ms, magicfile, FILE_LIST);
+}
+
+file_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
+ */
+file_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
+ */
+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);
+}
+
+file_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|O_CLOEXEC;
+ errno = 0;
+ if ((fd = open(inname, flags)) < 0) {
+ okstat = stat(inname, &sb) == 0;
+#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 O_CLOEXEC == 0 && defined(F_SETFD)
+ (void)fcntl(fd, F_SETFD, FD_CLOEXEC);
+#endif
+ }
+
+ if (fd != -1) {
+ 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 =
+#ifdef 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;
+}
+
+
+file_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
+
+file_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;
+}
+
+file_public int
+magic_errno(struct magic_set *ms)
+{
+ if (ms == NULL)
+ return EINVAL;
+ return (ms->event_flags & EVENT_HAD_ERR) ? ms->error : 0;
+}
+
+file_public int
+magic_getflags(struct magic_set *ms)
+{
+ if (ms == NULL)
+ return -1;
+
+ return ms->flags;
+}
+
+file_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;
+}
+
+file_public int
+magic_version(void)
+{
+ return MAGIC_VERSION;
+}
+
+file_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_SHSIZE_MAX:
+ ms->elf_shsize_max = *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;
+ case MAGIC_PARAM_ENCODING_MAX:
+ ms->encoding_max = *CAST(const size_t *, val);
+ return 0;
+ default:
+ errno = EINVAL;
+ return -1;
+ }
+}
+
+file_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_SHSIZE_MAX:
+ *CAST(size_t *, val) = ms->elf_shsize_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;
+ case MAGIC_PARAM_ENCODING_MAX:
+ *CAST(size_t *, val) = ms->encoding_max;
+ return 0;
+ default:
+ errno = EINVAL;
+ return -1;
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-02 10:55:56 +0000