generic-library/ffmpeg
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prefer avio_check() over url_exist()

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The problem with url_exist() is that it tries to open a resource in
RDONLY mode. If the file is a FIFO and there is already a reading
client, the open() call will hang.

By using avio_check() with access mode of 0, the second reading
process will check if the file exists without attempting to open it,
thus avoiding the lock.

Fix issue #1663.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
This commit is contained in:
Stefano Sabatini 2011-04-09 01:32:37 +02:00 committed by Anton Khirnov
parent 59d96941f0
commit 55815edca0
3 changed files with 6 additions and 6 deletions
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2
ffmpeg.c
View File

@ -3733,7 +3733,7 @@ static void opt_output_file(const char *filename)
(strchr(filename, ':') == NULL || (strchr(filename, ':') == NULL ||
filename[1] == ':' || filename[1] == ':' ||
av_strstart(filename, "file:", NULL))) { av_strstart(filename, "file:", NULL))) {
if (url_exist(filename)) { if (avio_check(filename, 0) == 0) {
if (!using_stdin) { if (!using_stdin) {
fprintf(stderr,"File '%s' already exists. Overwrite ? [y/N] ", filename); fprintf(stderr,"File '%s' already exists. Overwrite ? [y/N] ", filename);
fflush(stderr); fflush(stderr);

4
ffserver.c
View File

@ -3679,7 +3679,7 @@ static void build_feed_streams(void)
for(feed = first_feed; feed != NULL; feed = feed->next_feed) { for(feed = first_feed; feed != NULL; feed = feed->next_feed) {
int fd; int fd;
if (url_exist(feed->feed_filename)) { if (avio_check(feed->feed_filename, AVIO_FLAG_READ) > 0) {
/* See if it matches */ /* See if it matches */
AVFormatContext *s; AVFormatContext *s;
int matches = 0; int matches = 0;
@ -3752,7 +3752,7 @@ static void build_feed_streams(void)
unlink(feed->feed_filename); unlink(feed->feed_filename);
} }
} }
if (!url_exist(feed->feed_filename)) { if (avio_check(feed->feed_filename, AVIO_FLAG_WRITE) <= 0) {
AVFormatContext s1 = {0}, *s = &s1; AVFormatContext s1 = {0}, *s = &s1;
if (feed->readonly) { if (feed->readonly) {

6
libavformat/img2.c
View File

@ -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){ if (av_get_frame_filename(buf, sizeof(buf), path, first_index) < 0){
*pfirst_index = *pfirst_index =
*plast_index = 1; *plast_index = 1;
if(url_exist(buf)) if (avio_check(buf, AVIO_FLAG_READ) > 0)
return 0; return 0;
return -1; return -1;
} }
if (url_exist(buf)) if (avio_check(buf, AVIO_FLAG_READ) > 0)
break; break;
} }
if (first_index == 5) 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, if (av_get_frame_filename(buf, sizeof(buf), path,
last_index + range1) < 0) last_index + range1) < 0)
goto fail; goto fail;
if (!url_exist(buf)) if (avio_check(buf, AVIO_FLAG_READ) <= 0)
break; break;
range = range1; range = range1;
/* just in case... */ /* just in case... */