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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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34
libc/include/stdio.h
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@@ -170,6 +170,7 @@ __END_DECLS
#define __SOFF 0x1000 /* set iff _offset is in fact correct */
#define __SMOD 0x2000 /* true => fgetln modified _p text */
#define __SALC 0x4000 /* allocate string space dynamically */
#define __SIGN 0x8000 /* ignore this file in _fwalk */
/*
* The following three definitions are for ANSI C, which took them
@@ -406,38 +407,43 @@ static __inline int __sputc(int _c, FILE *_p) {
#define __sclearerr(p) ((void)((p)->_flags &= ~(__SERR|__SEOF)))
#define __sfileno(p) ((p)->_file)
#define feof(p) __sfeof(p)
#define ferror(p) __sferror(p)
extern int __isthreaded;
#ifndef _POSIX_THREADS
#define clearerr(p) __sclearerr(p)
#endif
#define feof(p) (!__isthreaded ? __sfeof(p) : (feof)(p))
#define ferror(p) (!__isthreaded ? __sferror(p) : (ferror)(p))
#define clearerr(p) (!__isthreaded ? __sclearerr(p) : (clearerr)(p))
#if __POSIX_VISIBLE
#define fileno(p) __sfileno(p)
#define fileno(p) (!__isthreaded ? __sfileno(p) : (fileno)(p))
#endif
#define getc(fp) (!__isthreaded ? __sgetc(fp) : (getc)(fp))
#if __BSD_VISIBLE
/*
* The macro implementations of putc and putc_unlocked are not
* fully POSIX compliant; they do not set errno on failure
*/
#define putc(x, fp) (!__isthreaded ? __sputc(x, fp) : (putc)(x, fp))
#endif /* __BSD_VISIBLE */
#ifndef lint
#ifndef _POSIX_THREADS
#define getc(fp) __sgetc(fp)
#endif /* _POSIX_THREADS */
#if __POSIX_VISIBLE >= 199506
#define getc_unlocked(fp) __sgetc(fp)
/*
* The macro implementations of putc and putc_unlocked are not
* fully POSIX compliant; they do not set errno on failure
*/
#if __BSD_VISIBLE
#ifndef _POSIX_THREADS
#define putc(x, fp) __sputc(x, fp)
#endif /* _POSIX_THREADS */
#define putc_unlocked(x, fp) __sputc(x, fp)
#endif /* __BSD_VISIBLE */
#endif /* __POSIX_VISIBLE >= 199506 */
#endif /* lint */
#define getchar() getc(stdin)
#define putchar(x) putc(x, stdout)
#define getchar_unlocked() getc_unlocked(stdin)
#define putchar_unlocked(c) putc_unlocked(c, stdout)
#define getchar_unlocked() getc_unlocked(stdin)
#define putchar_unlocked(c) putc_unlocked(c, stdout)
#ifdef _GNU_SOURCE
/*