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/freopen.c b/libc/stdio/freopen.c
index 59b2228..da3a674 100644
--- a/libc/stdio/freopen.c
+++ b/libc/stdio/freopen.c
@@ -59,6 +59,8 @@
if (!__sdidinit)
__sinit();
+ FLOCKFILE(fp);
+
/*
* There are actually programs that depend on being able to "freopen"
* descriptors that weren't originally open. Keep this from breaking.
@@ -120,6 +122,7 @@
if (f < 0) { /* did not get it after all */
fp->_flags = 0; /* set it free */
+ FUNLOCKFILE(fp);
errno = sverrno; /* restore in case _close clobbered */
return (NULL);
}
@@ -154,5 +157,6 @@
*/
if (oflags & O_APPEND)
(void) __sseek((void *)fp, (fpos_t)0, SEEK_END);
+ FUNLOCKFILE(fp);
return (fp);
}