wiretap/mp4.c

   1 /* mp4.c
   2  *
   3  * MP4 (ISO/IEC 14496-12) file format decoder for the Wiretap library.
   4  *
   5  * Wiretap Library
   6  *
   7  * SPDX-License-Identifier: GPL-2.0-or-later
   8  */
   9
  10 #include "mp4.h"
  11
  12 #include <string.h>
  13
  14 #include "file_wrappers.h"
  15 #include "wtap-int.h"
  16
  17 static const uint8_t mp4_magic[] = { 'f', 't', 'y', 'p' };
  18 static const uint8_t mp4_magic_sidx[] = { 's', 'i', 'd', 'x' };
  19 static const uint8_t mp4_magic_styp[] = { 's', 't', 'y', 'p' };
  20
  21 static int mp4_file_type_subtype = -1;
  22
  23 void register_mp4(void);
  24
  25 wtap_open_return_val
  26 mp4_open(wtap *wth, int *err, char **err_info)
  27 {
  28         char magic_buf[8];
  29         int bytes_read;
  30
  31         bytes_read = file_read(magic_buf, sizeof (magic_buf), wth->fh);
  32
  33         if (bytes_read < 0) {
  34                 *err = file_error(wth->fh, err_info);
  35                 return WTAP_OPEN_ERROR;
  36         }
  37         if (bytes_read == 0)
  38                 return WTAP_OPEN_NOT_MINE;
  39
  40         if (bytes_read == sizeof (magic_buf) &&
  41                         memcmp(magic_buf + 4, mp4_magic, sizeof (mp4_magic)) &&
  42                         memcmp(magic_buf + 4, mp4_magic_sidx, sizeof (mp4_magic_sidx)) &&
  43                         memcmp(magic_buf + 4, mp4_magic_styp, sizeof (mp4_magic_styp)))
  44                 return WTAP_OPEN_NOT_MINE;
  45
  46         if (file_seek(wth->fh, 0, SEEK_SET, err) == -1)
  47                 return WTAP_OPEN_ERROR;
  48
  49         wth->file_type_subtype = mp4_file_type_subtype;
  50         wth->file_encap = WTAP_ENCAP_MP4;
  51         wth->file_tsprec = WTAP_TSPREC_SEC;
  52         wth->subtype_read = wtap_full_file_read;
  53         wth->subtype_seek_read = wtap_full_file_seek_read;
  54         wth->snapshot_length = 0;
  55
  56         return WTAP_OPEN_MINE;
  57 }
  58
  59 static const struct supported_block_type mp4_blocks_supported[] = {
  60         /*
  61          * This is a file format that we dissect, so we provide
  62          * only one "packet" with the file's contents, and don't
  63          * support any options.
  64          */
  65         { WTAP_BLOCK_PACKET, ONE_BLOCK_SUPPORTED, NO_OPTIONS_SUPPORTED }
  66 };
  67
  68 static const struct file_type_subtype_info mp4_info = {
  69         "MP4 media", "mp4", "mp4", NULL,
  70         false, BLOCKS_SUPPORTED(mp4_blocks_supported),
  71         NULL, NULL, NULL
  72 };
  73
  74 void register_mp4(void)
  75 {
  76         mp4_file_type_subtype = wtap_register_file_type_subtype(&mp4_info);
  77
  78         /*
  79          * Register name for backwards compatibility with the
  80          * wtap_filetypes table in Lua.
  81          */
  82         wtap_register_backwards_compatibility_lua_name("MP4",
  83             mp4_file_type_subtype);
  84 }
  85
  86 /*
  87  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
  88  *
  89  * Local variables:
  90  * c-basic-offset: 8
  91  * tab-width: 8
  92  * indent-tabs-mode: t
  93  * End:
  94  *
  95  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
  96  * :indentSize=8:tabSize=8:noTabs=false:
  97  */