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flock.c

/*
 * Copyright (c) 2003 QUALCOMM Incorporated.  All rights reserved.
 * The file License.txt specifies the terms for use, modification,
 * and redistribution.
 */


/*
 * Copyright (c) 1989 Mark Davies
 * Copyright (c) 1990 Andy Linton
 * Copyright (c) 1990 Victoria University of Wellington.
 *
 * Redistribution and use in source and binary forms are permitted provided
 * that: (1) source distributions retain this entire copyright notice and
 * comment, and (2) distributions including binaries display the following
 * acknowledgement:  ``This product includes software developed by the
 * Victoria University of Wellington, New Zealand and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software.
 * 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */


#include "config.h"

#ifndef HAVE_FLOCK /*  defined(SYSV) || defined(ISC) */

#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
#ifdef ISC
#  include <net/errno.h>
#endif
#include <flock.h>               /* defines normally in <sys/file.h> */


#if defined(F_SETLK) && defined(F_SETLKW)

int
flock(fd, operation)
int fd, operation;
{
    int op, ret;
    struct flock arg;
    extern int errno;

    op = (LOCK_NB & operation) ? F_SETLK : F_SETLKW;
    
    arg.l_type = (LOCK_EX & operation) ? F_WRLCK :
        (LOCK_SH & operation) ? F_RDLCK : F_UNLCK;
    arg.l_whence = arg.l_start = arg.l_len = 0;
    
    if ((ret = fcntl(fd, op, &arg)) == -1) {
        if (errno == EACCES || errno == EAGAIN)
            errno = EWOULDBLOCK;
    }
    return (ret);
}

#else

int
flock(fd, operation)
int fd, operation;
{
    int op, ret;
    extern int errno;

    op = (LOCK_UN & operation) ? F_ULOCK :
      (LOCK_NB & operation) ? F_TLOCK : F_LOCK;

    if ((ret = lockf(fd, op, 0)) == -1) {
        if (errno == EACCES || errno == EAGAIN)
            errno = EWOULDBLOCK;
    }

    return (ret);
}

#endif /* F_SETLK && F_SETLKW */

#endif /* HAVE_FLOCK */


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