magic.c

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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.
 */
 
#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>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#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
 
#ifdef PHP_WIN32
# undef S_IFLNK
# undef S_IFIFO
#endif
 
file_private int unreadable_info(struct magic_set *, mode_t, const char *);
file_private const char *file_or_stream(struct magic_set *, const char *, php_stream *);
 
#ifndef STDIN_FILENO
#define STDIN_FILENO    0
#endif
 
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);
}
 
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);
}
 
#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_stream(ms, NULL, NULL);
}
 
/*
 * 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_stream(ms, inname, NULL);
}
 
file_public const char *
magic_stream(struct magic_set *ms, php_stream *stream)
{
    if (ms == NULL)
        return NULL;
    return file_or_stream(ms, NULL, stream);
}
 
file_private const char *
file_or_stream(struct magic_set *ms, const char *inname, php_stream *stream)
{
    int rv = -1;
    unsigned char *buf;
    zend_stat_t   sb = {0};
    ssize_t nbytes = 0; /* number of bytes read from a datafile */
    int no_in_stream = 0;
 
    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 *, emalloc(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;
    }
 
    errno = 0;
 
    if (inname && !stream) {
        no_in_stream = 1;
        stream = php_stream_open_wrapper((char *)inname, "rb", REPORT_ERRORS, NULL);
        if (!stream) {
            if (unreadable_info(ms, sb.st_mode, inname) == -1)
                goto done;
            rv = -1;
            goto done;
        }
    }
 
    php_stream_statbuf ssb;
    if (php_stream_stat(stream, &ssb) < 0) {
        if (ms->flags & MAGIC_ERROR) {
            file_error(ms, errno, "cannot stat `%s'", inname);
            rv = -1;
            goto done;
        }
    }
    memcpy(&sb, &ssb.sb, sizeof(zend_stat_t));
 
    /*
     * try looking at the first ms->bytes_max bytes
     */
    if ((nbytes = php_stream_read(stream, (char *)buf, ms->bytes_max - nbytes)) < 0) {
        file_error(ms, errno, "cannot read `%s'", inname);
        goto done;
    }
 
    (void)memset(buf + nbytes, 0, SLOP); /* NUL terminate */
    if (file_buffer(ms, stream, &sb, inname, buf, CAST(size_t, nbytes)) == -1)
        goto done;
    rv = 0;
done:
    efree(buf);
 
    if (no_in_stream && stream) {
        php_stream_close(stream);
    }
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, NULL, 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;
    }
}