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Fix the handle locking in stdio

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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
This commit is contained in:
Kenny Root
2011-02-12 07:13:44 -08:00
parent 72f9a5c374
commit f582340a6a
36 changed files with 239 additions and 92 deletions
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16
libc/stdio/ungetc.c
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@@ -82,17 +82,20 @@ ungetc(int c, FILE *fp)
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 @@ ungetc(int c, FILE *fp)
*/
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 @@ ungetc(int c, FILE *fp)
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 @@ ungetc(int c, FILE *fp)
fp->_ubuf[sizeof(fp->_ubuf) - 1] = c;
fp->_p = &fp->_ubuf[sizeof(fp->_ubuf) - 1];
fp->_r = 1;
FUNLOCKFILE(fp);
return (c);
}