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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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6
libc/stdio/wbuf.c
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@@ -65,20 +65,20 @@ __swbuf(int c, FILE *fp)
* stuff c into the buffer. If this causes the buffer to fill
* completely, or if c is '\n' and the file is line buffered,
* flush it (perhaps a second time). The second flush will always
* happen on unbuffered streams, where _bf._size==1; fflush()
* happen on unbuffered streams, where _bf._size==1; __sflush()
* guarantees that putc() will always call wbuf() by setting _w
* to 0, so we need not do anything else.
*/
n = fp->_p - fp->_bf._base;
if (n >= fp->_bf._size) {
if (fflush(fp))
if (__sflush(fp))
return (EOF);
n = 0;
}
fp->_w--;
*fp->_p++ = c;
if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n'))
if (fflush(fp))
if (__sflush(fp))
return (EOF);
return (c);
}