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Diffstat (limited to 'mit-pthreads/pthreads/file.c')
| -rw-r--r-- | mit-pthreads/pthreads/file.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/mit-pthreads/pthreads/file.c b/mit-pthreads/pthreads/file.c new file mode 100644 index 00000000000..4b8a8aad6db --- /dev/null +++ b/mit-pthreads/pthreads/file.c @@ -0,0 +1,129 @@ +/* ==== file.c ============================================================ + * Copyright (c) 1993, 1994 by Chris Provenzano, proven@mit.edu + * All rights reserved. + * + * 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 Chris Provenzano. + * 4. The name of Chris Provenzano may not be used to endorse or promote + * products derived from this software without specific prior written + * permission. + * + * THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``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 CHRIS PROVENZANO 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. + * + * Description : The locking functions for stdio. + * + * 1.00 93/09/04 proven + * -Started coding this file. + */ + +#ifndef lint +static const char rcsid[] = "$Id$"; +#endif + +#include <pthread.h> +#include <stdio.h> + +/* ========================================================================== + * flockfile() + */ +void flockfile(FILE *fp) +{ + pthread_mutex_t *mutex; + int fd, flags; + + if ((fd = fileno(fp)) >= 0) { + pthread_mutex_lock(mutex = &(fd_table[fd]->mutex)); + + if (fp->_flags & __SRW) { + flags = FD_READ | FD_WRITE; + } else { + if (fp->_flags & __SWR) { + flags = FD_WRITE; + } else { + flags = FD_READ; + } + } + + /* This might fail but POSIX doesn't give a damn. */ + fd_basic_lock(fd, flags, mutex, NULL); + pthread_mutex_unlock(mutex); + } +} + +/* ========================================================================== + * ftrylockfile() + */ +int ftrylockfile(FILE *fp) +{ + pthread_mutex_t *mutex; + int fd, flags; + + if ((fd = fileno(fp)) >= 0) { + pthread_mutex_lock(mutex = &(fd_table[fd]->mutex)); + + if (fp->_flags & __SRW) { + flags = FD_READ | FD_WRITE; + } else { + if (fp->_flags & __SWR) { + flags = FD_WRITE; + } else { + flags = FD_READ; + } + } + if (!(fd_table[fd]->r_owner && fd_table[fd]->w_owner)) { + fd_basic_lock(fd, flags, mutex, NULL); + fd = OK; + } else { + fd = NOTOK; + } + pthread_mutex_unlock(mutex); + } else { + fd = OK; + } + return(fd); +} + +/* ========================================================================== + * funlockfile() + */ +void funlockfile(FILE *fp) +{ + pthread_mutex_t *mutex; + int fd, flags; + + if ((fd = fileno(fp)) >= 0) { + pthread_mutex_lock(mutex = &(fd_table[fd]->mutex)); + + if (fp->_flags & __SRW) { + flags = FD_READ | FD_WRITE; + } else { + if (fp->_flags & __SWR) { + flags = FD_WRITE; + } else { + flags = FD_READ; + } + } + fd_basic_unlock(fd, flags); + pthread_mutex_unlock(mutex); + } +} + |