wiretap/mime_file.c

   1 /* mime_file.c
   2  *
   3  * MIME file format decoder for the Wiretap library.
   4  *
   5  * $Id$
   6  *
   7  * Wiretap Library
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version 2
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21  */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26
  27 #ifdef HAVE_SYS_TYPES_H
  28 #include <sys/types.h>
  29 #endif
  30
  31 #ifdef HAVE_UNISTD_H
  32 #include <unistd.h>
  33 #endif
  34
  35 #include <errno.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <time.h>
  39
  40 #include "wtap-int.h"
  41 #include "file_wrappers.h"
  42 #include "buffer.h"
  43 #include "mime_file.h"
  44
  45 typedef struct {
  46         gboolean last_packet;
  47
  48 } mime_file_private_t;
  49
  50 typedef struct {
  51         const guchar *magic;
  52         guint magic_len;
  53 } mime_files_t;
  54
  55 /*
  56  * Written by Marton Nemeth <nm127@freemail.hu>
  57  * Copyright 2009 Marton Nemeth
  58  * The JPEG and JFIF specification can be found at:
  59  *
  60  * http://www.jpeg.org/public/jfif.pdf
  61  * http://www.w3.org/Graphics/JPEG/itu-t81.pdf
  62  */
  63 static const guchar jpeg_jfif_magic[] = { 0xFF, 0xD8, /* SOF */
  64                                           0xFF        /* start of the next marker */
  65                                         };
  66
  67 static const mime_files_t magic_files[] = {
  68         { jpeg_jfif_magic, sizeof(jpeg_jfif_magic) }
  69 };
  70
  71 #define N_MAGIC_TYPES   (sizeof(magic_files) / sizeof(magic_files[0]))
  72
  73 static gboolean
  74 mime_read(wtap *wth, int *err, gchar **err_info, gint64 *data_offset)
  75 {
  76         mime_file_private_t *priv = (mime_file_private_t *) wth->priv;
  77
  78         char _buf[WTAP_MAX_PACKET_SIZE];
  79         guint8 *buf;
  80         int packet_size;
  81
  82         if (priv->last_packet) {
  83                 *err = file_error(wth->fh, err_info);
  84                 return FALSE;
  85         }
  86
  87         wth->phdr.ts.secs = (time_t) wth->data_offset;
  88         wth->phdr.ts.nsecs = 0;
  89
  90         *data_offset = wth->data_offset;
  91
  92         /* try to read max WTAP_MAX_PACKET_SIZE bytes */
  93         packet_size = file_read(_buf, sizeof(_buf), wth->fh);
  94
  95         if (packet_size <= 0) {
  96                 priv->last_packet = TRUE;
  97                 /* signal error for packet-mime-encap */
  98                 if (packet_size < 0)
  99                         wth->phdr.ts.nsecs = 1000000000;
 100
 101                 wth->phdr.caplen = 0;
 102                 wth->phdr.len = 0;
 103                 return TRUE;
 104         }
 105
 106         /* copy to wth frame buffer */
 107         buffer_assure_space(wth->frame_buffer, packet_size);
 108         buf = buffer_start_ptr(wth->frame_buffer);
 109         memcpy(buf, _buf, packet_size);
 110
 111         wth->data_offset += packet_size;
 112         wth->phdr.caplen = packet_size;
 113         wth->phdr.len = packet_size;
 114         return TRUE;
 115 }
 116
 117 static gboolean
 118 mime_seek_read(wtap *wth, gint64 seek_off, union wtap_pseudo_header *pseudo_header _U_, guchar *pd, int length, int *err, gchar **err_info)
 119 {
 120         if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1) {
 121                 *err_info = NULL;
 122                 return FALSE;
 123         }
 124
 125         wtap_file_read_expected_bytes(pd, length, wth->random_fh, err, err_info);
 126
 127         *err = 0;
 128         *err_info = NULL;
 129         return TRUE;
 130 }
 131
 132 int
 133 mime_file_open(wtap *wth, int *err, gchar **err_info)
 134 {
 135         char magic_buf[128]; /* increase buffer size when needed */
 136         int bytes_read;
 137         int ret;
 138         guint i;
 139
 140         guint read_bytes = 0;
 141
 142         for (i = 0; i < N_MAGIC_TYPES; i++)
 143                 read_bytes = MAX(read_bytes, magic_files[i].magic_len);
 144
 145         read_bytes = MIN(read_bytes, sizeof(magic_buf));
 146         bytes_read = file_read(magic_buf, read_bytes, wth->fh);
 147
 148         if (bytes_read > 0) {
 149                 gboolean found_file = FALSE;
 150                 /* guint file_ok; */
 151
 152                 for (i = 0; i < N_MAGIC_TYPES; i++) {
 153                         if ((guint) bytes_read >= magic_files[i].magic_len && !memcmp(magic_buf, magic_files[i].magic, MIN(magic_files[i].magic_len, (guint) bytes_read))) {
 154                                 if (!found_file) {
 155                                         found_file = TRUE;
 156                                         /* file_ok = i; */
 157                                 } else
 158                                         return 0;       /* many files matched, bad file */
 159                         }
 160                 }
 161
 162                 if (!found_file)
 163                         return 0;
 164
 165                 if (file_seek(wth->fh, 0, SEEK_SET, err) == -1)
 166                         return -1;
 167
 168                 wth->file_type = WTAP_FILE_MIME;
 169                 wth->file_encap = WTAP_ENCAP_MIME;
 170                 wth->tsprecision = WTAP_FILE_TSPREC_SEC;
 171                 wth->subtype_read = mime_read;
 172                 wth->subtype_seek_read = mime_seek_read;
 173                 wth->snapshot_length = 0;
 174                 ret = 1;
 175
 176                 wth->priv = g_malloc0(sizeof(mime_file_private_t));
 177
 178         } else {
 179                 *err = file_error(wth->fh, err_info);
 180                 ret = -1;
 181         }
 182         return ret;
 183 }
 184