/src/common/fd.h

  1/*****************************************************************************
  2 *  $Id$
  3 *****************************************************************************
  4 *  This file is part of the Munge Uid 'N' Gid Emporium (MUNGE).
  5 *  For details, see <http://www.llnl.gov/linux/munge/>.
  6 *  UCRL-CODE-2003-???.
  7 *
  8 *  Copyright (C) 2001-2003 The Regents of the University of California.
  9 *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
 10 *  Written by Chris Dunlap <cdunlap@llnl.gov>.
 11 *
 12 *  This is free software; you can redistribute it and/or modify it
 13 *  under the terms of the GNU General Public License as published by
 14 *  the Free Software Foundation; either version 2 of the License, or
 15 *  (at your option) any later version.
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 17 *  This is distributed in the hope that it will be useful, but WITHOUT
 18 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 19 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 20 *  for more details.
 21 *
 22 *  You should have received a copy of the GNU General Public License;
 23 *  if not, write to the Free Software Foundation, Inc., 59 Temple Place,
 24 *  Suite 330, Boston, MA  02111-1307  USA.
 25 *****************************************************************************/
 26
 27
 28#ifndef FD_H
 29#define FD_H
 30
 31
 32#if HAVE_CONFIG_H
 33#  include "config.h"
 34#endif /* HAVE_CONFIG_H */
 35
 36#include <sys/types.h>
 37#include <unistd.h>
 38
 39
 40int fd_set_close_on_exec (int fd);
 41/*
 42 *  Sets the file descriptor [fd] to be closed on exec().
 43 *  Returns 0 on success, or -1 on error.
 44 */
 45
 46int fd_set_nonblocking (int fd);
 47/*
 48 *  Sets the file descriptor [fd] for non-blocking I/O.
 49 *  Returns 0 on success, or -1 on error.
 50 */
 51
 52int fd_get_read_lock (int fd);
 53/*
 54 *  Obtain a read lock on the file specified by [fd].
 55 *  Returns 0 on success, or -1 if prevented from obtaining the lock.
 56 */
 57
 58int fd_get_readw_lock (int fd);
 59/*
 60 *  Obtain a read lock on the file specified by [fd],
 61 *    blocking until one becomes available.
 62 *  Returns 0 on success, or -1 on error.
 63 */
 64
 65int fd_get_write_lock (int fd);
 66/*
 67 *  Obtain a write lock on the file specified by [fd].
 68 *  Returns 0 on success, or -1 if prevented from obtaining the lock.
 69 */
 70
 71int fd_get_writew_lock (int fd);
 72/*
 73 *  Obtain a write lock on the file specified by [fd],
 74 *    blocking until one becomes available.
 75 *  Returns 0 on success, or -1 on error.
 76 */
 77
 78int fd_release_lock (int fd);
 79/*
 80 *  Release a lock held on the file specified by [fd].
 81 *  Returns 0 on success, or -1 on error.
 82 */
 83
 84pid_t fd_is_read_lock_blocked (int fd);
 85/*
 86 *  Checks to see if a lock exists on [fd] that would block a request for a
 87 *    read-lock (ie, if a write-lock is already being held on the file).
 88 *  Returns the pid of the process holding the lock, 0 if no lock exists,
 89 *    or -1 on error.
 90 */
 91
 92pid_t fd_is_write_lock_blocked (int fd);
 93/*
 94 *  Checks to see if a lock exists on [fd] that would block a request for a
 95 *    write-lock (ie, if any lock is already being held on the file).
 96 *  Returns the pid of the process holding the lock, 0 if no lock exists,
 97 *    or -1 on error.
 98 */
 99
100ssize_t fd_read_n (int fd, void *buf, size_t n);
101/*
102 *  Reads up to [n] bytes from [fd] into [buf].
103 *  Returns the number of bytes read, 0 on EOF, or -1 on error.
104 */
105
106ssize_t fd_write_n (int fd, void *buf, size_t n);
107/*
108 *  Writes [n] bytes from [buf] to [fd].
109 *  Returns the number of bytes written, or -1 on error.
110 */
111
112ssize_t fd_read_line (int fd, void *buf, size_t maxlen);
113/*
114 *  Reads at most [maxlen-1] bytes up to a newline from [fd] into [buf].
115 *  The [buf] is guaranteed to be NUL-terminated and will contain the
116 *    newline if it is encountered within [maxlen-1] bytes.
117 *  Returns the number of bytes read, 0 on EOF, or -1 on error.
118 */
119
120ssize_t fd_null_read_n (int fd, void *buf, size_t maxlen);
121/*
122 *  Reads up to [n] bytes from [fd] into [buf].
123 *  Returns the number of bytes read, 0 on EOF, or -1 on error.
124 *  Differs from fd_read_n() in that it checks for the presence
125 *  a null along the partial read and breaks out if it does.
126 *  Added by Mike Haskell <mhaskell@llnl.gov>
127 */
128
129#endif /* !FD_H */