root/fileinfo/libmagic/magic.c

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DEFINITIONS

This source file includes following definitions.
  1. FILE_RCSID
  2. magic_getpath
  3. magic_open
  4. free_mlist
  5. unreadable_info
  6. magic_close
  7. magic_load
  8. magic_compile
  9. magic_list
  10. close_and_restore
  11. magic_descriptor
  12. magic_file
  13. magic_stream
  14. file_or_stream
  15. magic_buffer
  16. magic_error
  17. magic_errno
  18. magic_setflags

/*
 * 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.
 */

#include "file.h"

#ifndef lint
FILE_RCSID("@(#)$File: magic.c,v 1.74 2011/05/26 01:27:59 christos Exp $")
#endif  /* lint */

#include "magic.h"

#include <stdlib.h>
#ifdef PHP_WIN32
#include "win32/unistd.h"
#else
#include <unistd.h>
#endif
#include <string.h>
#ifdef PHP_WIN32
# include "config.w32.h"
#else
# include "php_config.h"
#endif

#ifdef PHP_WIN32
#include <shlwapi.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

#ifdef PHP_WIN32
# undef S_IFLNK
# undef S_IFIFO
#endif

private void free_mlist(struct mlist *);
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);
private const char *file_or_stream(struct magic_set *, const char *, php_stream *);

#ifndef STDIN_FILENO
#define STDIN_FILENO    0
#endif

/* XXX this functionality is excluded in php, enable it in apprentice.c:340 */
#if 0
private const char *
get_default_magic(void)
{
        static const char hmagic[] = "/.magic/magic.mgc";
        static char *default_magic;
        char *home, *hmagicpath;

#ifndef PHP_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", 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
        char *hmagicp = hmagicpath;
        char *tmppath = NULL;
        LPTSTR dllpath;

#define APPENDPATH() \
        do { \
                if (tmppath && access(tmppath, R_OK) != -1) { \
                        if (hmagicpath == NULL) \
                                hmagicpath = tmppath; \
                        else { \
                                if (asprintf(&hmagicp, "%s%c%s", hmagicpath, \
                                    PATHSEP, tmppath) >= 0) { \
                                        free(hmagicpath); \
                                        hmagicpath = hmagicp; \
                                } \
                                free(tmppath); \
                        } \
                        tmppath = NULL; \
                } \
        } while (/*CONSTCOND*/0)
                                
        if (default_magic) {
                free(default_magic);
                default_magic = NULL;
        }

        /* First, try to get user-specific magic file */
        if ((home = getenv("LOCALAPPDATA")) == NULL) {
                if ((home = getenv("USERPROFILE")) != NULL)
                        if (asprintf(&tmppath,
                            "%s/Local Settings/Application Data%s", home,
                            hmagic) < 0)
                                tmppath = NULL;
        } else {
                if (asprintf(&tmppath, "%s%s", home, hmagic) < 0)
                        tmppath = NULL;
        }

        APPENDPATH();

        /* Second, try to get a magic file from Common Files */
        if ((home = getenv("COMMONPROGRAMFILES")) != NULL) {
                if (asprintf(&tmppath, "%s%s", home, hmagic) >= 0)
                        APPENDPATH();
        }

        /* Third, try to get magic file relative to dll location */
        dllpath = malloc(sizeof(*dllpath) * (MAX_PATH + 1));
        dllpath[MAX_PATH] = 0;  /* just in case long path gets truncated and not null terminated */
        if (GetModuleFileNameA(NULL, dllpath, MAX_PATH)){
                PathRemoveFileSpecA(dllpath);
                if (strlen(dllpath) > 3 &&
                    stricmp(&dllpath[strlen(dllpath) - 3], "bin") == 0) {
                        if (asprintf(&tmppath,
                            "%s/../share/misc/magic.mgc", dllpath) >= 0)
                                APPENDPATH();
                } else {
                        if (asprintf(&tmppath,
                            "%s/share/misc/magic.mgc", dllpath) >= 0)
                                APPENDPATH();
                        else if (asprintf(&tmppath,
                            "%s/magic.mgc", dllpath) >= 0)
                                APPENDPATH();
                }
        }

        /* Don't put 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;
}
#endif

public struct magic_set *
magic_open(int flags)
{
        struct magic_set *ms;

        ms = ecalloc((size_t)1, sizeof(struct magic_set));

        if (magic_setflags(ms, flags) == -1) {
                errno = EINVAL;
                goto free;
        }

        ms->o.buf = ms->o.pbuf = NULL;

        ms->c.li = emalloc((ms->c.len = 10) * sizeof(*ms->c.li));
        
        ms->event_flags = 0;
        ms->error = -1;
        ms->mlist = NULL;
        ms->file = "unknown";
        ms->line = 0;
        return ms;
free:
        efree(ms);
        return NULL;
}

private void
free_mlist(struct mlist *mlist)
{
        struct mlist *ml;

        if (mlist == NULL)
                return;

        for (ml = mlist->next; ml != mlist;) {
                struct mlist *next = ml->next;
                struct magic *mg = ml->magic;
                file_delmagic(mg, ml->mapped, ml->nmagic);
                efree(ml);
                ml = next;
        }
        efree(ml);
}

private int
unreadable_info(struct magic_set *ms, mode_t md, const char *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->mlist) {
                free_mlist(ms->mlist);
        }
        if (ms->o.pbuf) {
                efree(ms->o.pbuf);
        }
        if (ms->o.buf) {
                efree(ms->o.buf);
        }
        if (ms->c.li) {
                efree(ms->c.li);
        }
        efree(ms);
}

/*
 * load a magic file
 */
public int
magic_load(struct magic_set *ms, const char *magicfile)
{
        struct mlist *ml = file_apprentice(ms, magicfile, FILE_LOAD);
        if (ml) {
                free_mlist(ms->mlist);
                ms->mlist = ml;
                return 0;
        }
        return -1;
}

public int
magic_compile(struct magic_set *ms, const char *magicfile)
{
        struct mlist *ml = file_apprentice(ms, magicfile, FILE_COMPILE);
        free_mlist(ml);
        return ml ? 0 : -1;
}


public int
magic_list(struct magic_set *ms, const char *magicfile)
{
        struct mlist *ml = file_apprentice(ms, magicfile, FILE_LIST);
        free_mlist(ml);
        return ml ? 0 : -1;
}

private void
close_and_restore(const struct magic_set *ms, const char *name, int fd,
    const struct stat *sb)
{

        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
        }
}


/*
 * find type of descriptor
 */
public const char *
magic_descriptor(struct magic_set *ms, int fd)
{
        return file_or_stream(ms, NULL, NULL);
}

/*
 * find type of named file
 */
public const char *
magic_file(struct magic_set *ms, const char *inname)
{
        return file_or_stream(ms, inname, NULL);
}

public const char *
magic_stream(struct magic_set *ms, php_stream *stream)
{
        return file_or_stream(ms, NULL, stream);
}

private const char *
file_or_stream(struct magic_set *ms, const char *inname, php_stream *stream)
{
        int     rv = -1;
        unsigned char *buf;
        struct stat     sb;
        ssize_t nbytes = 0;     /* number of bytes read from a datafile */
        int no_in_stream = 0;
        TSRMLS_FETCH();

        if (!inname && !stream) {
                return NULL;
        }

        /*
         * one extra for terminating '\0', and
         * some overlapping space for matches near EOF
         */
#define SLOP (1 + sizeof(union VALUETYPE))
        buf = emalloc(HOWMANY + SLOP);

        if (file_reset(ms) == -1)
                goto done;

        switch (file_fsmagic(ms, inname, &sb, stream)) {
        case -1:                /* error */
                goto done;
        case 0:                 /* nothing found */
                break;
        default:                /* matched it and printed type */
                rv = 0;
                goto done;
        }

        errno = 0;

        if (!stream && inname) {
                no_in_stream = 1;
#if PHP_API_VERSION < 20100412
                stream = php_stream_open_wrapper((char *)inname, "rb", REPORT_ERRORS|ENFORCE_SAFE_MODE, NULL);
#else
                stream = php_stream_open_wrapper((char *)inname, "rb", REPORT_ERRORS, NULL);
#endif
        }

        if (!stream) {
                if (unreadable_info(ms, sb.st_mode, inname) == -1)
                        goto done;
                rv = 0;
                goto done;
        }

#ifdef O_NONBLOCK
/* we should be already be in non blocking mode for network socket */
#endif

        /*
         * try looking at the first HOWMANY bytes
         */
        if ((nbytes = php_stream_read(stream, (char *)buf, HOWMANY)) < 0) {
                file_error(ms, errno, "cannot read `%s'", inname);
                goto done;
        }

        (void)memset(buf + nbytes, 0, SLOP); /* NUL terminate */
        if (file_buffer(ms, stream, inname, buf, (size_t)nbytes) == -1)
                goto done;
        rv = 0;
done:
        efree(buf);

        if (no_in_stream && stream) {
                php_stream_close(stream);
        }

        close_and_restore(ms, inname, 0, &sb);
        return rv == 0 ? file_getbuffer(ms) : NULL;
}


public const char *
magic_buffer(struct magic_set *ms, const void *buf, size_t nb)
{
        if (file_reset(ms) == -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, NULL, NULL, buf, nb) == -1) {
                return NULL;
        }
        return file_getbuffer(ms);
}

public const char *
magic_error(struct magic_set *ms)
{
        return (ms->event_flags & EVENT_HAD_ERR) ? ms->o.buf : NULL;
}

public int
magic_errno(struct magic_set *ms)
{
        return (ms->event_flags & EVENT_HAD_ERR) ? ms->error : 0;
}

public int
magic_setflags(struct magic_set *ms, int flags)
{
#if !defined(HAVE_UTIME) && !defined(HAVE_UTIMES)
        if (flags & MAGIC_PRESERVE_ATIME)
                return -1;
#endif
        ms->flags = flags;
        return 0;
}

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