Fixes an issue where an int64_t ffurl_seek return-value was being stored
in a generic int "r" variable, leading to integer overflow when seeking
into a large file (>2GB), and ultimately a "Failed to perform internal
seek" error mesage. The "r" variable was used both for storing the
result of any seeks and for the result of any reads. Instead, I separate
the variable into an int64_t seek-variable and int read-variable.
To test, try running `ffprobe 'cache:http://<something>'` on a file that
is ~3GB large, whose moov atom is at the end of the file
---
libavformat/cache.c | 49 +++++++++++++++++++++++++------------------------
1 files changed, 25 insertions(+), 24 deletions(-)
diff --git a/libavformat/cache.c b/libavformat/cache.c
index a762aa9..b654f45 100644
--- a/libavformat/cache.c
+++ b/libavformat/cache.c
@@ -156,7 +156,8 @@ static int cache_read(URLContext *h, unsigned char *buf,
int size)
{
Context *c= h->priv_data;
CacheEntry *entry, *next[2] = {NULL, NULL};
- int r;
+ int64_t off;
+ int bytes_read = 0;
entry = av_tree_find(c->root, &c->logical_pos, cmp, (void**)next);
@@ -169,21 +170,21 @@ static int cache_read(URLContext *h, unsigned char *buf,
int size)
if (in_block_pos < entry->size) {
int64_t physical_target = entry->physical_pos + in_block_pos;
- if (c->cache_pos != physical_target) {
- r = lseek(c->fd, physical_target, SEEK_SET);
- } else
- r = c->cache_pos;
+ if (c->cache_pos != physical_target)
+ off = lseek(c->fd, physical_target, SEEK_SET);
+ else
+ off = c->cache_pos;
- if (r >= 0) {
- c->cache_pos = r;
- r = read(c->fd, buf, FFMIN(size, entry->size - in_block_pos));
+ if (off >= 0) {
+ c->cache_pos = off;
+ bytes_read = read(c->fd, buf, FFMIN(size, entry->size -
in_block_pos));
}
- if (r > 0) {
- c->cache_pos += r;
- c->logical_pos += r;
+ if (bytes_read > 0) {
+ c->cache_pos += bytes_read;
+ c->logical_pos += bytes_read;
c->cache_hit ++;
- return r;
+ return bytes_read;
}
}
}
@@ -191,30 +192,30 @@ static int cache_read(URLContext *h, unsigned char *buf,
int size)
// Cache miss or some kind of fault with the cache
if (c->logical_pos != c->inner_pos) {
- r = ffurl_seek(c->inner, c->logical_pos, SEEK_SET);
- if (r<0) {
+ off = ffurl_seek(c->inner, c->logical_pos, SEEK_SET);
+ if (off<0) {
av_log(h, AV_LOG_ERROR, "Failed to perform internal seek\n");
- return r;
+ return off;
}
- c->inner_pos = r;
+ c->inner_pos = off;
}
- r = ffurl_read(c->inner, buf, size);
- if (r == 0 && size>0) {
+ bytes_read = ffurl_read(c->inner, buf, size);
+ if (bytes_read == 0 && size>0) {
c->is_true_eof = 1;
av_assert0(c->end >= c->logical_pos);
}
- if (r<=0)
- return r;
- c->inner_pos += r;
+ if (bytes_read<=0)
+ return bytes_read;
+ c->inner_pos += bytes_read;
c->cache_miss ++;
- add_entry(h, buf, r);
- c->logical_pos += r;
+ add_entry(h, buf, bytes_read);
+ c->logical_pos += bytes_read;
c->end = FFMAX(c->end, c->logical_pos);
- return r;
+ return bytes_read;
}
static int64_t cache_seek(URLContext *h, int64_t pos, int whence)
--
1.7.1
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