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/ungetc.c b/libc/stdio/ungetc.c
index fe05258..b493d21 100644
--- a/libc/stdio/ungetc.c
+++ b/libc/stdio/ungetc.c
@@ -82,17 +82,20 @@
return (EOF);
if (!__sdidinit)
__sinit();
+ FLOCKFILE(fp);
_SET_ORIENTATION(fp, -1);
if ((fp->_flags & __SRD) == 0) {
/*
* Not already reading: no good unless reading-and-writing.
* Otherwise, flush any current write stuff.
*/
- if ((fp->_flags & __SRW) == 0)
+ if ((fp->_flags & __SRW) == 0) {
+error: FUNLOCKFILE(fp);
return (EOF);
+ }
if (fp->_flags & __SWR) {
if (__sflush(fp))
- return (EOF);
+ goto error;
fp->_flags &= ~__SWR;
fp->_w = 0;
fp->_lbfsize = 0;
@@ -107,9 +110,10 @@
*/
if (HASUB(fp)) {
if (fp->_r >= _UB(fp)._size && __submore(fp))
- return (EOF);
+ goto error;
*--fp->_p = c;
- fp->_r++;
+inc_ret: fp->_r++;
+ FUNLOCKFILE(fp);
return (c);
}
fp->_flags &= ~__SEOF;
@@ -122,8 +126,7 @@
if (fp->_bf._base != NULL && fp->_p > fp->_bf._base &&
fp->_p[-1] == c) {
fp->_p--;
- fp->_r++;
- return (c);
+ goto inc_ret;
}
/*
@@ -137,5 +140,6 @@
fp->_ubuf[sizeof(fp->_ubuf) - 1] = c;
fp->_p = &fp->_ubuf[sizeof(fp->_ubuf) - 1];
fp->_r = 1;
+ FUNLOCKFILE(fp);
return (c);
}