Fix the handle locking in stdio
Fix the handle locking in stdio to use flockfile/funlockfile
internally when and where required. Macros in <stdio.h> are updated
to automatically call the underlying functions when the process is
threaded to obtain the necessary locking. A private mutex is added
to protect __sglue, the internal list of FILE handles, and another
to protect the one-time initialization. Some routines in libc that
use getc() change to use getc_unlocked() as they're either protected
by their own lock or aren't thread-safe routines anyway.
Based on OpenBSD change by guenther@openbsd.org
http://www.mail-archive.com/source-changes@cvs.openbsd.org/msg01015.html
Bug: 3446659
Change-Id: Ie82116e358c541718d6709ec45ca6796be5a007b
diff --git a/libc/stdio/gets.c b/libc/stdio/gets.c
index 004eb99..93e2edd 100644
--- a/libc/stdio/gets.c
+++ b/libc/stdio/gets.c
@@ -32,6 +32,7 @@
*/
#include <stdio.h>
+#include "local.h"
__warn_references(gets,
"warning: gets() is very unsafe; consider using fgets()");
@@ -42,14 +43,17 @@
int c;
char *s;
- for (s = buf; (c = getchar()) != '\n';)
+ FLOCKFILE(stdin);
+ for (s = buf; (c = getchar_unlocked()) != '\n';)
if (c == EOF)
- if (s == buf)
+ if (s == buf) {
+ FUNLOCKFILE(stdin);
return (NULL);
- else
+ } else
break;
else
*s++ = c;
*s = '\0';
+ FUNLOCKFILE(stdin);
return (buf);
}