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/setvbuf.c b/libc/stdio/setvbuf.c
index 9b92bf0..2fb76af 100644
--- a/libc/stdio/setvbuf.c
+++ b/libc/stdio/setvbuf.c
@@ -61,6 +61,7 @@
* malloc()ed. We also clear any eof condition, as if this were
* a seek.
*/
+ FLOCKFILE(fp);
ret = 0;
(void)__sflush(fp);
if (HASUB(fp))
@@ -107,6 +108,7 @@
fp->_w = 0;
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
+ FUNLOCKFILE(fp);
return (ret);
}
flags |= __SMBF;
@@ -145,6 +147,7 @@
/* begin/continue reading, or stay in intermediate state */
fp->_w = 0;
}
+ FUNLOCKFILE(fp);
__atexit_register_cleanup(_cleanup);
return (ret);