[FFmpeg-cvslog] segment: Fix the failure paths

[Luca Barbato]

ffmpeg | branch: release/2.4 | Luca Barbato <lu_zero at gentoo.org> | Mon Jan  5 10:40:41 2015 +0100| [f6c82b34a320f105af266997f5951cbe7dfc8a05] | committer: Luca Barbato

segment: Fix the failure paths

A failure in segment_end() or segment_start() would lead to freeing
a dangling pointer and in general further calls to seg_write_packet()
or to seg_write_trailer() would have the same faulty behaviour.

CC: libav-stable at libav.org
Reported-By: luodalongde at gmail.com
(cherry picked from commit b3f04657368a32a9903406395f865e230b1de348)
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f6c82b34a320f105af266997f5951cbe7dfc8a05
---

 libavformat/segment.c |   32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/libavformat/segment.c b/libavformat/segment.c
index 9c757e4..61ec93f 100644
--- a/libavformat/segment.c
+++ b/libavformat/segment.c
@@ -183,6 +183,13 @@ static void close_null_ctx(AVIOContext *pb)
     av_free(pb);
 }
 
+static void seg_free_context(SegmentContext *seg)
+{
+    avio_closep(&seg->pb);
+    avformat_free_context(seg->avf);
+    seg->avf = NULL;
+}
+
 static int seg_write_header(AVFormatContext *s)
 {
     SegmentContext *seg = s->priv_data;
@@ -264,12 +271,9 @@ static int seg_write_header(AVFormatContext *s)
     }
 
 fail:
-    if (ret) {
-        if (seg->list)
-            avio_close(seg->pb);
-        if (seg->avf)
-            avformat_free_context(seg->avf);
-    }
+    if (ret < 0)
+        seg_free_context(seg);
+
     return ret;
 }
 
@@ -281,6 +285,9 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
     int64_t end_pts = seg->recording_time * seg->number;
     int ret, can_split = 1;
 
+    if (!oc)
+        return AVERROR(EINVAL);
+
     if (seg->has_video) {
         can_split = st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
                     pkt->flags & AV_PKT_FLAG_KEY;
@@ -321,11 +328,8 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
     ret = ff_write_chained(oc, pkt->stream_index, pkt, s);
 
 fail:
-    if (ret < 0) {
-        if (seg->list)
-            avio_close(seg->pb);
-        avformat_free_context(oc);
-    }
+    if (ret < 0)
+        seg_free_context(seg);
 
     return ret;
 }
@@ -334,7 +338,11 @@ static int seg_write_trailer(struct AVFormatContext *s)
 {
     SegmentContext *seg = s->priv_data;
     AVFormatContext *oc = seg->avf;
-    int ret;
+    int ret = 0;
+
+    if (!oc)
+        goto fail;
+
     if (!seg->write_header_trailer) {
         if ((ret = segment_end(oc, 0)) < 0)
             goto fail;