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/fflush.c b/libc/stdio/fflush.c
index 3f72ad8..e69bdcc 100644
--- a/libc/stdio/fflush.c
+++ b/libc/stdio/fflush.c
@@ -39,14 +39,18 @@
int
fflush(FILE *fp)
{
+ int r;
if (fp == NULL)
- return (_fwalk(__sflush));
+ return (_fwalk(__sflush_locked));
+ FLOCKFILE(fp);
if ((fp->_flags & (__SWR | __SRW)) == 0) {
errno = EBADF;
- return (EOF);
- }
- return (__sflush(fp));
+ r = EOF;
+ } else
+ r = __sflush(fp);
+ FUNLOCKFILE(fp);
+ return (r);
}
int
@@ -80,3 +84,14 @@
}
return (0);
}
+
+int
+__sflush_locked(FILE *fp)
+{
+ int r;
+
+ FLOCKFILE(fp);
+ r = __sflush(fp);
+ FUNLOCKFILE(fp);
+ return (r);
+}