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.
diff --git a/src/stdio/fileno.c b/src/stdio/fileno.c
index ba7f939..0bd0e98 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);