[FFmpeg-devel] [PATCH] avformat/file: fail for non-numerical arguments to pipe:

[Nils Goroll]

Before this patch, the implementation of pipe: inputs/outputs would
silently fall back to stdin/stdout for any argument not successfully
parsed by strtol().

This patch introduces an explicit error for any non-numerical arguments,
which should avoid user confusion as in #10977.

New behavior:

$ cat /tmp/video.mkv | ./ffmpeg -i pipe:aa -acodec copy -vcodec copy -f matroska 
pipe:1 | cat >/tmp/out.mkv

[pipe @ 0x5618c7bcf740] Non-numerical argument "aa" to pipe:
[in#0 @ 0x5618c7bced00] Error opening input: Invalid argument
Error opening input file pipe:aa.
Error opening input files: Invalid argument

Signed-off-by: Nils Goroll <nils.goroll at uplex.de>
---
  libavformat/file.c | 19 +++++++++++--------
  1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/libavformat/file.c b/libavformat/file.c
index 0b7452bc20..317a769e32 100644
--- a/libavformat/file.c
+++ b/libavformat/file.c
@@ -437,18 +437,21 @@ static int pipe_open(URLContext *h, const char *filename, 
int flags)
  {
      FileContext *c = h->priv_data;
      int fd;
-    char *final;
+    char *final = NULL;
       if (c->fd < 0) {
          av_strstart(filename, "pipe:", &filename);
  -        fd = strtol(filename, &final, 10);
-        if((filename == final) || *final ) {/* No digits found, or something 
like 10ab */
-            if (flags & AVIO_FLAG_WRITE) {
-                fd = 1;
-            } else {
-                fd = 0;
-            }
+        if (*filename == '\0')
+                fd = (flags & AVIO_FLAG_WRITE) ? 1 : 0;
+        else
+                fd = strtol(filename, &final, 10);
+
+        if (final != NULL && *final != '\0') {
+                av_log(h, AV_LOG_ERROR,
+                    "Non-numerical argument \"%s\" to pipe:\n",
+		    filename);
+                return AVERROR(EINVAL);
          }
          c->fd = fd;
      }
-- 
2.39.2