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authorRich Felker <dalias@aerifal.cx>2018-08-28 18:40:15 -0400
committerRich Felker <dalias@aerifal.cx>2018-08-28 18:41:12 -0400
commitb39b47bac8ee5505cfc595000a140c35460e1cac (patch)
tree4541df8890654a784bdb40b9f5fe94dc028ea2e8 /src/stdio/fileno.c
parentbaf95a5aefe885ef8a675759c63d43649d312ec6 (diff)
downloadmusl-b39b47bac8ee5505cfc595000a140c35460e1cac.tar.gz
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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/stdio/fileno.c')
-rw-r--r--src/stdio/fileno.c11
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);