From: Stefano Sabatini <stefano.sabatini-l...@poste.it>
The problem with url_exist() is that it tries to open a file in RDONLY
mode. If the file is a FIFO and there is a reading client, the open()
call will hang, and the ffmpeg process will get stuck.
Using avio_check() with no access mode of ~0 check if the file simply
exists without attempting to open it, thus avoiding locks.
Fix issue #1663.
---
ffmpeg.c | 2 +-
ffserver.c | 4 ++--
libavformat/avio.c | 2 ++
libavformat/avio.h | 3 +++
libavformat/img2.c | 6 +++---
5 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/ffmpeg.c b/ffmpeg.c
index 46adb9a..3cd887b 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -3733,7 +3733,7 @@ static void opt_output_file(const char *filename)
(strchr(filename, ':') == NULL ||
filename[1] == ':' ||
av_strstart(filename, "file:", NULL))) {
- if (url_exist(filename)) {
+ if (avio_check(filename, 0) != AVERROR(ENOENT)) {
if (!using_stdin) {
fprintf(stderr,"File '%s' already exists. Overwrite ?
[y/N] ", filename);
fflush(stderr);
diff --git a/ffserver.c b/ffserver.c
index eab8ae2..dd8ed23 100644
--- a/ffserver.c
+++ b/ffserver.c
@@ -3684,7 +3684,7 @@ static void build_feed_streams(void)
for(feed = first_feed; feed != NULL; feed = feed->next_feed) {
int fd;
- if (url_exist(feed->feed_filename)) {
+ if (avio_check(feed->feed_filename, URL_RDONLY) > 0) {
/* See if it matches */
AVFormatContext *s;
int matches = 0;
@@ -3757,7 +3757,7 @@ static void build_feed_streams(void)
unlink(feed->feed_filename);
}
}
- if (!url_exist(feed->feed_filename)) {
+ if (avio_check(feed->feed_filename, URL_RDONLY) <= 0) {
AVFormatContext s1 = {0}, *s = &s1;
if (feed->readonly) {
diff --git a/libavformat/avio.c b/libavformat/avio.c
index ecc7f27..f811073 100644
--- a/libavformat/avio.c
+++ b/libavformat/avio.c
@@ -365,6 +365,7 @@ int ffurl_close(URLContext *h)
return ret;
}
+#if FF_API_OLD_AVIO
int url_exist(const char *filename)
{
URLContext *h;
@@ -373,6 +374,7 @@ int url_exist(const char *filename)
ffurl_close(h);
return 1;
}
+#endif
int avio_check(const char *url, int flags)
{
diff --git a/libavformat/avio.h b/libavformat/avio.h
index 823aa97..806822c 100644
--- a/libavformat/avio.h
+++ b/libavformat/avio.h
@@ -119,11 +119,14 @@ attribute_deprecated int64_t av_url_read_seek(URLContext
*h, int stream_index,
attribute_deprecated void url_set_interrupt_cb(int (*interrupt_cb)(void));
#endif
+#if FF_API_OLD_AVIO
/**
* Return a non-zero value if the resource indicated by url
* exists, 0 otherwise.
*/
+attribute_deprecated
int url_exist(const char *url);
+#endif
/**
* Return a positive value if the resource indicated by url can be
diff --git a/libavformat/img2.c b/libavformat/img2.c
index 2b5d63b..917bae6 100644
--- a/libavformat/img2.c
+++ b/libavformat/img2.c
@@ -131,11 +131,11 @@ static int find_image_range(int *pfirst_index, int
*plast_index,
if (av_get_frame_filename(buf, sizeof(buf), path, first_index) < 0){
*pfirst_index =
*plast_index = 1;
- if(url_exist(buf))
+ if (avio_check(buf, URL_RDONLY) != AVERROR(ENOENT))
return 0;
return -1;
}
- if (url_exist(buf))
+ if (avio_check(buf, URL_RDONLY) != AVERROR(ENOENT))
break;
}
if (first_index == 5)
@@ -153,7 +153,7 @@ static int find_image_range(int *pfirst_index, int
*plast_index,
if (av_get_frame_filename(buf, sizeof(buf), path,
last_index + range1) < 0)
goto fail;
- if (!url_exist(buf))
+ if (avio_check(buf, URL_RDONLY) == AVERROR(ENOENT))
break;
range = range1;
/* just in case... */
--
1.7.4.1
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