musl - musl - an implementation of the standard library for Linux-based systems

musl - an implementation of the standard library for Linux-based systems

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author	Rich Felker <dalias@aerifal.cx>	2018年08月28日 18:40:15 -0400
committer	Rich Felker <dalias@aerifal.cx>	2018年08月28日 18:41:12 -0400
commit	b39b47bac8ee5505cfc595000a140c35460e1cac (patch)
tree	4541df8890654a784bdb40b9f5fe94dc028ea2e8 /src
parent	baf95a5aefe885ef8a675759c63d43649d312ec6 (diff)
download	musl-b39b47bac8ee5505cfc595000a140c35460e1cac.tar.gz

set errno when fileno is called on a FILE with no underlying fd

this is a POSIX requirement. also remove the gratuitous locking shenanigans and simply access f->fd under control of the lock. there is no advantage to not doing so, and it made the correctness non-obvious at best.

Diffstat (limited to 'src')

-rw-r--r--

src/stdio/fileno.c

1 files changed, 7 insertions, 4 deletions

diff --git a/src/stdio/fileno.c b/src/stdio/fileno.c
index ba7f9391..0bd0e988 100644
--- a/src/stdio/fileno.c
+++ b/src/stdio/fileno.c

@@ -1,13 +1,16 @@

#include "stdio_impl.h"

+#include <errno.h>

int fileno(FILE *f)

{

- /* f->fd never changes, but the lock must be obtained and released

- * anyway since this function cannot return while another thread

- * holds the lock. */

FLOCK(f);

+ int fd = f->fd;

FUNLOCK(f);

- return f->fd;

+ if (fd < 0) {

+ errno = EBADF;

+ return -1;

+ }

+ return fd;

}

weak_alias(fileno, fileno_unlocked);

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