From 40e7b3ce74e32798e742725d743e484f11766ba4 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Sun, 30 Jun 2019 02:45:00 +0100 Subject: [PATCH] tools: mkenvimage: Fix reading from slow pipe It is perfectly fine for the read(2) syscall to return with less than the requested number of bytes read (short read, see the "RETURN VALUE" section of the man page). This typically happens with slow input (keyboard, network) or with complex pipes. So far mkenvimage expects the exact number of requested bytes to be read, assuming an end-of-file condition otherwise. This wrong behaviour can be easily shown with: $ (echo "foo=bar"; sleep 1; echo "bar=baz") | mkenvimage -s 256 -o out - The second line will be missing from the output. Correct this by checking for any positive, non-zero return value. This fixes a problem with a complex pipe in one of my scripts, where the environment consist of two parts. Signed-off-by: Andre Przywara Acked-by: Alexander Dahl --- tools/mkenvimage.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/tools/mkenvimage.c b/tools/mkenvimage.c index 75967d0c2d..ffaebd5565 100644 --- a/tools/mkenvimage.c +++ b/tools/mkenvimage.c @@ -173,8 +173,7 @@ int main(int argc, char **argv) return EXIT_FAILURE; } filesize += readbytes; - } while (readbytes == readlen); - + } while (readbytes > 0); } else { txt_filename = argv[optind]; txt_fd = open(txt_filename, O_RDONLY); -- 2.25.1