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Diffstat (limited to 'mit-pthreads/stdio/freopen.c')
| -rw-r--r-- | mit-pthreads/stdio/freopen.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/mit-pthreads/stdio/freopen.c b/mit-pthreads/stdio/freopen.c new file mode 100644 index 00000000000..f45571c8ea0 --- /dev/null +++ b/mit-pthreads/stdio/freopen.c @@ -0,0 +1,149 @@ +/*- + * Copyright (c) 1990 The Regents of the University of California. + * Copyright (c) 1993, 1994 Chris Provenzano. + * All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Chris Torek. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +/*static char *sccsid = "from: @(#)freopen.c 5.6 (Berkeley) 2/24/91";*/ +static char *rcsid = "$Id$"; +#endif /* LIBC_SCCS and not lint */ + +#include <pthread.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> +#include <unistd.h> +#include <stdio.h> +#include <stdlib.h> +#include "local.h" + +extern pthread_mutex_t __sfp_mutex; +extern pthread_cond_t __sfp_cond; +extern int __sfp_state; + +/* + * Re-direct an existing, open (probably) file to some other file. + * ANSI is written such that the original file gets closed if at + * all possible, no matter what. + */ +FILE * +freopen(file, mode, fp) + const char *file, *mode; + register FILE *fp; +{ + int f, flags, oflags; + FILE *ret; + + if ((flags = __sflags(mode, &oflags)) == 0) { + (void) fclose(fp); + return (NULL); + } + + __sinit (); + + /* + * There are actually programs that depend on being able to "freopen" + * descriptors that weren't originally open. Keep this from breaking. + * Remember whether the stream was open to begin with, and which file + * descriptor (if any) was associated with it. If it was attached to + * a descriptor, defer closing it; freopen("/dev/stdin", "r", stdin) + * should work. This is unnecessary if it was not a Unix file. + */ + /* while lock __sfp_mutex, to block out fopen, and other freopen calls */ + while (pthread_mutex_lock(&__sfp_mutex) == OK) { + if (ftrylockfile(fp) == OK) { + if (fp->_flags) { + /* flush the stream; ANSI doesn't require this. */ + if (fp->_flags & __SWR) + (void) __sflush(fp); + __sclose(fp); + /* + * Finish closing fp. We cannot keep fp->_base: + * it may be the wrong size. This loses the effect + * of any setbuffer calls, but stdio has always done + * this before. + * NOTE: We do this even if __ftrylockfilr failed with + * an error to avoid memory leaks. + */ + if (fp->_flags & __SMBF) + free((char *)fp->_bf._base); + fp->_w = 0; + fp->_r = 0; + fp->_p = NULL; + fp->_bf._base = NULL; + fp->_bf._size = 0; + fp->_lbfsize = 0; + if (HASUB(fp)) + FREEUB(fp); + fp->_ub._size = 0; + if (HASLB(fp)) + FREELB(fp); + fp->_lb._size = 0; + } + /* Get a new descriptor to refer to the new file. */ + if ((f = open(file, oflags, 0666)) < OK) + ret = NULL; + /* + * If reopening something that was open before on a real file, try + * to maintain the descriptor. Various C library routines (perror) + * assume stderr is always fd STDERR_FILENO, even if being + * freopen'd. + */ + /* Testing f == fp->_file may no longer be necessary */ + if (fp->_file >= 0 && f != fp->_file) { + if (dup2(f, fp->_file) >= OK) { + (void)close(f); + f = fp->_file; + } + } + fp->_flags = flags; + fp->_file = f; + ret = fp; + } else { + /* unlock __sfp_mutex, and try again later */ + pthread_mutex_unlock(&__sfp_mutex); + pthread_yield(); + continue; + } + /* @@ Yo, Chris! Between the "break" and "continue" statements + above, the program will never get here. What gives? */ + pthread_mutex_unlock(&__sfp_mutex); + funlockfile(fp); + return(ret); + } + (void)fclose(fp); + return(NULL); +} |