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/fwrite.c b/libc/stdio/fwrite.c
index 8a508dc..a97313e 100644
--- a/libc/stdio/fwrite.c
+++ b/libc/stdio/fwrite.c
@@ -45,6 +45,7 @@
size_t n;
struct __suio uio;
struct __siov iov;
+ int ret;
iov.iov_base = (void *)buf;
uio.uio_resid = iov.iov_len = n = count * size;
@@ -56,7 +57,10 @@
* skip the divide if this happens, since divides are
* generally slow and since this occurs whenever size==0.
*/
- if (__sfvwrite(fp, &uio) == 0)
+ FLOCKFILE(fp);
+ ret = __sfvwrite(fp, &uio);
+ FUNLOCKFILE(fp);
+ if (ret == 0)
return (count);
return ((n - uio.uio_resid) / size);
}