From: Rich Felker <dalias@aerifal.cx>
Date: Tue, 28 Aug 2018 22:40:15 +0000 (-0400)
Subject: set errno when fileno is called on a FILE with no underlying fd
X-Git-Tag: v1.1.20~17
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=b39b47bac8ee5505cfc595000a140c35460e1cac;p=oweals%2Fmusl.git

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 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);