/*
 * 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 1.78 2013/01/07 18:20:19 christos Exp $")
#endif  /* lint */

#include "magic.h" // @nolint

#include <stdlib.h>
#ifdef PHP_WIN32
#include "win32/unistd.h" // @nolint
#else
#include <unistd.h>
#endif
#include <string.h>

#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 close_and_restore(const struct magic_set *, const char *, int,
    const struct stat *);
private int unreadable_info(struct magic_set *, mode_t, const char *);
#if 0
private const char* get_default_magic(void);
#endif
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.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
  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)
{
  return file_ms_alloc(flags);
}

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 == 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);
}

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_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 ((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)
{
  if (ms == NULL)
    return NULL;
  return file_or_stream(ms, NULL, NULL);
}

/*
 * 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_stream(ms, inname, NULL);
}

public const char *
magic_stream(struct magic_set *ms, php_stream *stream)
{
  if (ms == NULL)
    return NULL;
  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 */
  HPHP::req::ptr<HPHP::File> file;

  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 = (unsigned char*) 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) {
    auto wrapper = HPHP::Stream::getWrapperFromURI(inname);
    if (wrapper) file = wrapper->open(inname, "rb", 0, nullptr);
    stream = file.get();
  }

  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 = stream->readImpl((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);

  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 (ms == NULL)
    return NULL;
  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)
{
  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_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;
}
