[FFmpeg-devel] [PATCH] libavformat/dashdec: Fix for ticket 6658 (Dash demuxer segfault)
Colin NG
colin_ng at hotmail.com
Wed Dec 6 01:57:26 EET 2017
________________________________
From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> on behalf of Steven Liu <lingjiujianke at gmail.com>
Sent: December 4, 2017 4:52 AM
To: FFmpeg development discussions and patches
Subject: Re: [FFmpeg-devel] [PATCH] libavformat/dashdec: Fix for ticket 6658 (Dash demuxer segfault)
2017-12-04 12:28 GMT+08:00 Colin NG <colin_ng at hotmail.com>:
> ---
> libavformat/dashdec.c | 112 ++++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 99 insertions(+), 13 deletions(-)
>
> diff --git a/libavformat/dashdec.c b/libavformat/dashdec.c
> index 3798649..d04bec0 100644
> --- a/libavformat/dashdec.c
> +++ b/libavformat/dashdec.c
> @@ -148,6 +148,11 @@ static uint64_t get_current_time_in_sec(void)
> return av_gettime() / 1000000;
> }
>
> +static char * ishttp(char *url) {
> + char *proto_name = avio_find_protocol_name(url);
> + return av_strstart(proto_name, "http", NULL);
> +}
> +
> static uint64_t get_utc_date_time_insec(AVFormatContext *s, const char *datetime)
> {
> struct tm timeinfo;
> @@ -392,7 +397,9 @@ static int open_url(AVFormatContext *s, AVIOContext **pb, const char *url,
> else if (strcmp(proto_name, "file") || !strncmp(url, "file,", 5))
> return AVERROR_INVALIDDATA;
>
> - ret = s->io_open(s, pb, url, AVIO_FLAG_READ, &tmp);
> + av_freep(pb);
> + ret = avio_open2(pb, url, AVIO_FLAG_READ, c->interrupt_callback, &tmp);
> +
> if (ret >= 0) {
> // update cookies on http response with setcookies.
> char *new_cookies = NULL;
> @@ -639,6 +646,87 @@ static int parse_manifest_segmenttimeline(AVFormatContext *s, struct representat
> return 0;
> }
>
> +static int resolve_content_path(AVFormatContext *s, const char *url, xmlNodePtr *baseurl_nodes, int n_baseurl_nodes) {
> +
> + int i;
> + char *text;
> + char *tmp_str = av_mallocz(MAX_URL_SIZE);
> + char *tmp_str_2= av_mallocz(MAX_URL_SIZE);
> +
> + char *path = av_mallocz(MAX_URL_SIZE);
> + int nameSize = 0;
> + int updated = 0;
> +
> + if (!tmp_str || !tmp_str_2 || !path) {
> + updated = AVERROR(ENOMEM);
> + goto end;
> + }
> +
> + av_strlcpy(tmp_str, url, strlen(url)+1);
> + char *mpdName = strtok (tmp_str," /");
> +
> + while ((mpdName =strtok (NULL, "/"))) {
What dose this do?
The above instruction will split the url (i.e. url of the mpd file) elements with "/" separator in between.
> + nameSize = strlen(mpdName);
> + }
> +
> + av_strlcpy (path, url, strlen(url)-nameSize+1);
> +
> + int rootId = 0;
> + xmlNodePtr *node = NULL;
> + for (rootId = n_baseurl_nodes-1; rootId >0; rootId--) {
> + if (!(node = baseurl_nodes[rootId])) {
> + continue;
> + }
> + if (ishttp(xmlNodeGetContent(node))) {
> + break;
> + }
> + }
> +
> + node = baseurl_nodes[rootId];
> + char *baseurl = xmlNodeGetContent(node);
> + char *root_url = (!av_strcasecmp(baseurl, ""))? path: baseurl;
> +
> + if (node) {
> + xmlNodeSetContent(node, root_url);
> + }
> +
> + int size = strlen(root_url);
> + char *isRootHttp= ishttp(root_url);
> +
> + char token ='/';
> + //if (root_url[size-1]==token) {
> + if (av_strncasecmp(&root_url[size-1],&token, 1) != 0) {
If this only compare 1 char, why don't use root_url[size-1] == token ?
> + av_strlcat(root_url, "/", size+2);
> + size+=2;
> + }
> +
> + for (i = 0; i < n_baseurl_nodes; ++i) {
> + if (i==rootId) {
> + continue;
> + }
> + text = xmlNodeGetContent(baseurl_nodes[i]);
> + if (text) {
> + memset(tmp_str, 0, strlen(tmp_str));
> +
> + if (!ishttp(text) && isRootHttp) {
> + av_strlcpy(tmp_str, root_url, size+1);
> + }
> + int start = (text[0]==token) ? 1: 0;
> + memset(tmp_str_2, 0, strlen(tmp_str_2));
> + av_strlcat(tmp_str, text+start, MAX_URL_SIZE);
> + xmlFree(text);
> + xmlNodeSetContent(baseurl_nodes[i], tmp_str);
> + updated = 1;
> + }
> + }
> +
> +end:
> + av_free(path);
> + av_free(tmp_str);
> + av_free(tmp_str_2);
> + return updated;
> +
> +}
> static int parse_manifest_representation(AVFormatContext *s, const char *url,
> xmlNodePtr node,
> xmlNodePtr adaptionset_node,
> @@ -698,6 +786,12 @@ static int parse_manifest_representation(AVFormatContext *s, const char *url,
> baseurl_nodes[2] = adaptionset_baseurl_node;
> baseurl_nodes[3] = representation_baseurl_node;
>
> + ret = resolve_content_path(s, url, baseurl_nodes, 4);
> +
> + if (ret == AVERROR(ENOMEM)) {
What about ret < 0 ?
> + goto end;
> + }
> +
> if (representation_segmenttemplate_node || fragment_template_node) {
> fragment_timeline_node = NULL;
> fragment_templates_tab[0] = representation_segmenttemplate_node;
> @@ -993,6 +1087,9 @@ static int parse_manifest(AVFormatContext *s, const char *url, AVIOContext *in)
> }
>
> mpd_baseurl_node = find_child_node_by_name(node, "BaseURL");
> + if (!mpd_baseurl_node) {
> + mpd_baseurl_node = xmlNewNode(node, "BaseURL");
> + }
>
> // at now we can handle only one period, with the longest duration
> node = xmlFirstElementChild(node);
> @@ -1315,6 +1412,7 @@ static int read_from_url(struct representation *pls, struct fragment *seg,
> } else {
> ret = avio_read(pls->input, buf, buf_size);
> }
> +
> if (ret > 0)
> pls->cur_seg_offset += ret;
>
> @@ -1343,18 +1441,6 @@ static int open_input(DASHContext *c, struct representation *pls, struct fragmen
> goto cleanup;
> }
>
> - /* Seek to the requested position. If this was a HTTP request, the offset
> - * should already be where want it to, but this allows e.g. local testing
> - * without a HTTP server. */
> - if (!ret && seg->url_offset) {
> - int64_t seekret = avio_seek(pls->input, seg->url_offset, SEEK_SET);
> - if (seekret < 0) {
> - av_log(pls->parent, AV_LOG_ERROR, "Unable to seek to offset %"PRId64" of DASH fragment '%s'\n", seg->url_offset, seg->url);
> - ret = (int) seekret;
> - ff_format_io_close(pls->parent, &pls->input);
> - }
> - }
> -
> cleanup:
> av_dict_free(&opts);
> pls->cur_seg_offset = 0;
> --
> 2.7.4
>
Thanks
Steven
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