wiretap/tnef.c

   1 /* tnef.c
   2  *
   3  * Transport-Neutral Encapsulation Format (TNEF) file reading
   4  *
   5  * $Id$
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  */
  21
  22 #include "config.h"
  23
  24 #include <errno.h>
  25
  26 #ifdef HAVE_SYS_STAT_H
  27 #include <sys/stat.h>
  28 #endif
  29
  30 #include "wtap-int.h"
  31 #include "file_wrappers.h"
  32 #include "buffer.h"
  33 #include "tnef.h"
  34
  35 static gboolean tnef_read_file(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr,
  36                                Buffer *buf, int *err, gchar **err_info)
  37 {
  38   gint64 file_size;
  39   int packet_size;
  40
  41   if ((file_size = wtap_file_size(wth, err)) == -1)
  42     return FALSE;
  43
  44   if (file_size > WTAP_MAX_PACKET_SIZE) {
  45     /*
  46      * Probably a corrupt capture file; don't blow up trying
  47      * to allocate space for an immensely-large packet.
  48      */
  49     *err = WTAP_ERR_BAD_FILE;
  50     *err_info = g_strdup_printf("tnef: File has %" G_GINT64_MODIFIER "d-byte packet, bigger than maximum of %u",
  51                                 file_size, WTAP_MAX_PACKET_SIZE);
  52     return FALSE;
  53   }
  54   packet_size = (int)file_size;
  55
  56   phdr->presence_flags = 0; /* yes, we have no bananas^Wtime stamp */
  57
  58   phdr->caplen = packet_size;
  59   phdr->len = packet_size;
  60
  61   phdr->ts.secs = 0;
  62   phdr->ts.nsecs = 0;
  63
  64   return wtap_read_packet_bytes(fh, buf, packet_size, err, err_info);
  65 }
  66
  67 static gboolean tnef_read(wtap *wth, int *err, gchar **err_info, gint64 *data_offset)
  68 {
  69   gint64 offset;
  70
  71   *err = 0;
  72
  73   offset = file_tell(wth->fh);
  74
  75   /* there is only ever one packet */
  76   if (offset)
  77     return FALSE;
  78
  79   *data_offset = offset;
  80
  81   return tnef_read_file(wth, wth->fh, &wth->phdr, wth->frame_buffer, err, err_info);
  82 }
  83
  84 static gboolean tnef_seek_read(wtap *wth, gint64 seek_off,
  85                                struct wtap_pkthdr *phdr,
  86                                Buffer *buf, int length _U_, int *err, gchar **err_info)
  87 {
  88   /* there is only one packet */
  89   if(seek_off > 0) {
  90     *err = 0;
  91     return FALSE;
  92   }
  93
  94   if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
  95     return FALSE;
  96
  97   return tnef_read_file(wth, wth->random_fh, phdr, buf, err, err_info);
  98 }
  99
 100 int tnef_open(wtap *wth, int *err, gchar **err_info)
 101 {
 102   int bytes_read;
 103   guint32 magic;
 104
 105   bytes_read = file_read(&magic, sizeof magic, wth->fh);
 106   if (bytes_read != sizeof magic) {
 107     *err = file_error(wth->fh, err_info);
 108     return (*err != 0) ? -1 : 0;
 109   }
 110
 111   if (htolel(magic) != TNEF_SIGNATURE)
 112      /* Not a tnef file */
 113      return 0;
 114
 115   /* seek back to the start of the file  */
 116   if (file_seek(wth->fh, 0, SEEK_SET, err) == -1)
 117     return -1;
 118
 119   wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_TNEF;
 120   wth->file_encap = WTAP_ENCAP_TNEF;
 121   wth->snapshot_length = 0;
 122
 123   wth->subtype_read = tnef_read;
 124   wth->subtype_seek_read = tnef_seek_read;
 125   wth->tsprecision = WTAP_FILE_TSPREC_SEC;
 126
 127   return 1;
 128 }