libavformat/mpjpegdec.c

   1 /*
   2  * Multipart JPEG format
   3  * Copyright (c) 2015 Luca Barbato
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg 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 GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/avstring.h"
  23 #include "libavutil/opt.h"
  24
  25 #include "avformat.h"
  26 #include "internal.h"
  27 #include "avio_internal.h"
  28
  29
  30
  31 typedef struct MPJPEGDemuxContext {
  32     const AVClass *class;
  33     char       *boundary;
  34     char       *searchstr;
  35     int         searchstr_len;
  36     int         strict_mime_boundary;
  37 } MPJPEGDemuxContext;
  38
  39
  40 static void trim_right(char *p)
  41 {
  42     char *end;
  43
  44     if (!p || !*p)
  45         return;
  46
  47     end = p + strlen(p);
  48     while (end > p && av_isspace(*(end-1)))
  49         *(--end) = '\0';
  50 }
  51
  52 static int get_line(AVIOContext *pb, char *line, int line_size)
  53 {
  54     ff_get_line(pb, line, line_size);
  55
  56     if (pb->error)
  57         return pb->error;
  58
  59     if (pb->eof_reached)
  60         return AVERROR_EOF;
  61
  62     trim_right(line);
  63     return 0;
  64 }
  65
  66
  67
  68 static int split_tag_value(char **tag, char **value, char *line)
  69 {
  70     char *p = line;
  71     int  foundData = 0;
  72
  73     *tag = NULL;
  74     *value = NULL;
  75
  76
  77     while (*p != '\0' && *p != ':') {
  78         if (!av_isspace(*p)) {
  79             foundData = 1;
  80         }
  81         p++;
  82     }
  83     if (*p != ':')
  84         return foundData ? AVERROR_INVALIDDATA : 0;
  85
  86     *p   = '\0';
  87     *tag = line;
  88     trim_right(*tag);
  89
  90     p++;
  91
  92     while (av_isspace(*p))
  93         p++;
  94
  95     *value = p;
  96     trim_right(*value);
  97
  98     return 0;
  99 }
 100
 101 static int parse_multipart_header(AVIOContext *pb,
 102                                     int* size,
 103                                     const char* expected_boundary,
 104                                     void *log_ctx);
 105
 106 static int mpjpeg_read_close(AVFormatContext *s)
 107 {
 108     MPJPEGDemuxContext *mpjpeg = s->priv_data;
 109     av_freep(&mpjpeg->boundary);
 110     av_freep(&mpjpeg->searchstr);
 111     return 0;
 112 }
 113
 114 static int mpjpeg_read_probe(const AVProbeData *p)
 115 {
 116     AVIOContext pb;
 117     int ret = 0;
 118     int size = 0;
 119
 120     if (p->buf_size < 2 || p->buf[0] != '-' || p->buf[1] != '-')
 121         return 0;
 122
 123     ffio_init_context(&pb, p->buf, p->buf_size, 0, NULL, NULL, NULL, NULL);
 124
 125     ret = (parse_multipart_header(&pb, &size, "--", NULL) >= 0) ? AVPROBE_SCORE_MAX : 0;
 126
 127     return ret;
 128 }
 129
 130 static int mpjpeg_read_header(AVFormatContext *s)
 131 {
 132     AVStream *st;
 133     char boundary[70 + 2 + 1] = {0};
 134     int64_t pos = avio_tell(s->pb);
 135     int ret;
 136
 137     do {
 138         ret = get_line(s->pb, boundary, sizeof(boundary));
 139         if (ret < 0)
 140             return ret;
 141     } while (!boundary[0]);
 142
 143     if (strncmp(boundary, "--", 2))
 144         return AVERROR_INVALIDDATA;
 145
 146     st = avformat_new_stream(s, NULL);
 147     if (!st)
 148         return AVERROR(ENOMEM);
 149
 150     st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
 151     st->codecpar->codec_id   = AV_CODEC_ID_MJPEG;
 152
 153     avpriv_set_pts_info(st, 60, 1, 25);
 154
 155     avio_seek(s->pb, pos, SEEK_SET);
 156
 157     return 0;
 158 }
 159
 160 static int parse_content_length(const char *value)
 161 {
 162     long int val = strtol(value, NULL, 10);
 163
 164     if (val == LONG_MIN || val == LONG_MAX)
 165         return AVERROR(errno);
 166     if (val > INT_MAX)
 167         return AVERROR(ERANGE);
 168     return val;
 169 }
 170
 171 static int parse_multipart_header(AVIOContext *pb,
 172                             int* size,
 173                             const char* expected_boundary,
 174                             void *log_ctx)
 175 {
 176     char line[128];
 177     int found_content_type = 0;
 178     int ret;
 179
 180     *size = -1;
 181
 182     // get the CRLF as empty string
 183     ret = get_line(pb, line, sizeof(line));
 184     if (ret < 0)
 185         return ret;
 186
 187     /* some implementation do not provide the required
 188      * initial CRLF (see rfc1341 7.2.1)
 189      */
 190     while (!line[0]) {
 191         ret = get_line(pb, line, sizeof(line));
 192         if (ret < 0)
 193             return ret;
 194     }
 195
 196     if (!av_strstart(line, expected_boundary, NULL)) {
 197         if (log_ctx)
 198         av_log(log_ctx,
 199             AV_LOG_ERROR,
 200             "Expected boundary '%s' not found, instead found a line of %"SIZE_SPECIFIER" bytes\n",
 201             expected_boundary,
 202             strlen(line));
 203
 204         return AVERROR_INVALIDDATA;
 205     }
 206
 207     while (!pb->eof_reached) {
 208         char *tag, *value;
 209
 210         ret = get_line(pb, line, sizeof(line));
 211         if (ret < 0) {
 212             if (ret == AVERROR_EOF)
 213                 break;
 214             return ret;
 215         }
 216
 217         if (line[0] == '\0')
 218             break;
 219
 220         ret = split_tag_value(&tag, &value, line);
 221         if (ret < 0)
 222             return ret;
 223         if (value==NULL || tag==NULL)
 224             break;
 225
 226         if (!av_strcasecmp(tag, "Content-type")) {
 227             if (av_strcasecmp(value, "image/jpeg")) {
 228                 if (log_ctx)
 229                 av_log(log_ctx, AV_LOG_ERROR,
 230                            "Unexpected %s : %s\n",
 231                            tag, value);
 232                 return AVERROR_INVALIDDATA;
 233             } else
 234                 found_content_type = 1;
 235         } else if (!av_strcasecmp(tag, "Content-Length")) {
 236             *size = parse_content_length(value);
 237             if ( *size < 0 )
 238                 if (log_ctx)
 239                 av_log(log_ctx, AV_LOG_WARNING,
 240                            "Invalid Content-Length value : %s\n",
 241                            value);
 242         }
 243     }
 244
 245     return found_content_type ? 0 : AVERROR_INVALIDDATA;
 246 }
 247
 248
 249 static char* mpjpeg_get_boundary(AVIOContext* pb)
 250 {
 251     uint8_t *mime_type = NULL;
 252     const char *start;
 253     const char *end;
 254     uint8_t *res = NULL;
 255     int     len;
 256
 257     /* get MIME type, and skip to the first parameter */
 258     av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type);
 259     start = mime_type;
 260     while (start != NULL && *start != '\0') {
 261         start = strchr(start, ';');
 262         if (!start)
 263             break;
 264
 265         start = start+1;
 266
 267         while (av_isspace(*start))
 268             start++;
 269
 270         if (av_stristart(start, "boundary=", &start)) {
 271             end = strchr(start, ';');
 272             if (end)
 273                 len = end - start - 1;
 274             else
 275                 len = strlen(start);
 276
 277             /* some endpoints may enclose the boundary
 278               in Content-Type in quotes */
 279             if ( len>2 && *start == '"' && start[len-1] == '"' ) {
 280                 start++;
 281                 len -= 2;
 282             }
 283             res = av_strndup(start, len);
 284             break;
 285         }
 286     }
 287
 288     av_freep(&mime_type);
 289     return res;
 290 }
 291
 292
 293 static int mpjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
 294 {
 295     int size;
 296     int ret;
 297
 298     MPJPEGDemuxContext *mpjpeg = s->priv_data;
 299     if (mpjpeg->boundary == NULL) {
 300         uint8_t* boundary = NULL;
 301         if (mpjpeg->strict_mime_boundary) {
 302             boundary = mpjpeg_get_boundary(s->pb);
 303         }
 304         if (boundary != NULL) {
 305             mpjpeg->boundary = av_asprintf("--%s", boundary);
 306             mpjpeg->searchstr = av_asprintf("\r\n--%s\r\n", boundary);
 307             av_freep(&boundary);
 308         } else {
 309             mpjpeg->boundary = av_strdup("--");
 310             mpjpeg->searchstr = av_strdup("\r\n--");
 311         }
 312         if (!mpjpeg->boundary || !mpjpeg->searchstr) {
 313             av_freep(&mpjpeg->boundary);
 314             av_freep(&mpjpeg->searchstr);
 315             return AVERROR(ENOMEM);
 316         }
 317         mpjpeg->searchstr_len = strlen(mpjpeg->searchstr);
 318     }
 319
 320     ret = parse_multipart_header(s->pb, &size, mpjpeg->boundary, s);
 321
 322
 323     if (ret < 0)
 324         return ret;
 325
 326     if (size > 0) {
 327         /* size has been provided to us in MIME header */
 328         ret = av_get_packet(s->pb, pkt, size);
 329     } else {
 330         /* no size was given -- we read until the next boundary or end-of-file */
 331         int remaining = 0, len;
 332
 333         const int read_chunk = 2048;
 334
 335         pkt->pos  = avio_tell(s->pb);
 336
 337         while ((ret = ffio_ensure_seekback(s->pb, read_chunk - remaining)) >= 0 && /* we may need to return as much as all we've read back to the buffer */
 338                (ret = av_append_packet(s->pb, pkt, read_chunk - remaining)) >= 0) {
 339             /* scan the new data */
 340             char *start;
 341
 342             len = ret + remaining;
 343             start = pkt->data + pkt->size - len;
 344             do {
 345                 if (!memcmp(start, mpjpeg->searchstr, mpjpeg->searchstr_len)) {
 346                     // got the boundary! rewind the stream
 347                     avio_seek(s->pb, -len, SEEK_CUR);
 348                     pkt->size -= len;
 349                     return pkt->size;
 350                 }
 351                 len--;
 352                 start++;
 353             } while (len >= mpjpeg->searchstr_len);
 354             remaining = len;
 355         }
 356
 357         /* error or EOF occurred */
 358         if (ret == AVERROR_EOF) {
 359             ret = pkt->size > 0 ? pkt->size : AVERROR_EOF;
 360         }
 361     }
 362
 363     return ret;
 364 }
 365
 366 #define OFFSET(x) offsetof(MPJPEGDemuxContext, x)
 367
 368 #define DEC AV_OPT_FLAG_DECODING_PARAM
 369 static const AVOption mpjpeg_options[] = {
 370     { "strict_mime_boundary",  "require MIME boundaries match", OFFSET(strict_mime_boundary), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, DEC },
 371     { NULL }
 372 };
 373
 374
 375 static const AVClass mpjpeg_demuxer_class = {
 376     .class_name     = "MPJPEG demuxer",
 377     .item_name      = av_default_item_name,
 378     .option         = mpjpeg_options,
 379     .version        = LIBAVUTIL_VERSION_INT,
 380 };
 381
 382 AVInputFormat ff_mpjpeg_demuxer = {
 383     .name              = "mpjpeg",
 384     .long_name         = NULL_IF_CONFIG_SMALL("MIME multipart JPEG"),
 385     .mime_type         = "multipart/x-mixed-replace",
 386     .extensions        = "mjpg",
 387     .priv_data_size    = sizeof(MPJPEGDemuxContext),
 388     .read_probe        = mpjpeg_read_probe,
 389     .read_header       = mpjpeg_read_header,
 390     .read_packet       = mpjpeg_read_packet,
 391     .read_close        = mpjpeg_read_close,
 392     .priv_class        = &mpjpeg_demuxer_class,
 393     .flags             = AVFMT_NOTIMESTAMPS,
 394 };
 395
 396