usr/src/lib/libbc/libc/sys/common/ftruncate.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include <sys/syscall.h>
  30 #include <sys/types.h>
  31
  32 /* The following are from SVR4 sys/fcntl.h */
  33
  34 #define F_FREESP        11      /* Free file space */
  35 #define F_WRLCK         02      /* Write Lock */
  36
  37 /* lock structure from SVR4. */
  38 struct fl {
  39         short l_type;
  40         short l_whence;
  41         off_t l_start;
  42         off_t l_len;
  43         long  l_sysid;
  44         pid_t l_pid;
  45         long  pad[4];
  46 };
  47
  48 int
  49 ftruncate(int fd, off_t length)
  50 {
  51
  52         struct fl lck;
  53
  54         lck.l_whence = 0;       /* offset l_start from beginning of file */
  55         lck.l_start = length;
  56         lck.l_type = F_WRLCK;   /* setting a write lock */
  57         lck.l_len = 0L;
  58
  59         if (_syscall(SYS_fcntl, fd, F_FREESP, (int)&lck) == -1)
  60                 return (-1);
  61         else
  62                 return (0);
  63 }