usr/src/cmd/sgs/libelf/common/output.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 2009 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*
  28  *      Copyright (c) 1988 AT&T
  29  *        All Rights Reserved
  30  */
  31
  32 #include <sys/mman.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <unistd.h>
  36 #include <libelf.h>
  37 #include <errno.h>
  38 #include "decl.h"
  39 #include "msg.h"
  40
  41 /*
  42  * File output
  43  *      These functions write output files.
  44  *      On SVR4 and newer systems use mmap(2).  On older systems (or on
  45  *      file systems that don't support mmap), use write(2).
  46  */
  47
  48
  49 char *
  50 _elf_outmap(int fd, size_t sz, unsigned int *pflag)
  51 {
  52         char    *p;
  53
  54         /*
  55          * Note: Some NFS implementations do not provide from enlarging a file
  56          * via ftruncate(), thus this may fail with ENOSUP.  In this case the
  57          * fall through to the calloc() mechanism will occur.
  58          */
  59         if ((!*pflag) && (ftruncate(fd, (off_t)sz) == 0) &&
  60             (p = mmap(NULL, sz, PROT_READ+PROT_WRITE,
  61             MAP_SHARED, fd, (off_t)0)) != (char *)-1) {
  62                 *pflag = 1;
  63                 return (p);
  64         }
  65
  66         *pflag = 0;
  67
  68         /*
  69          * If mmap fails, try calloc.  Some file systems don't mmap.  Note, we
  70          * use calloc rather than malloc, as ld(1) assumes that the backing
  71          * storage it is working with is zero filled.
  72          */
  73         if ((p = (char *)calloc(1, sz)) == 0)
  74                 _elf_seterr(EMEM_OUT, errno);
  75         return (p);
  76 }
  77
  78
  79 size_t
  80 _elf_outsync(int fd, char *p, size_t sz, unsigned int flag)
  81 {
  82         if (flag != 0) {
  83                 int     err;
  84
  85                 if ((fd = msync(p, sz, MS_ASYNC)) == -1)
  86                         err = errno;
  87                 (void) munmap(p, sz);
  88                 if (fd == 0)
  89                         return (sz);
  90                 _elf_seterr(EIO_SYNC, err);
  91                 return (0);
  92         }
  93         if ((lseek(fd, 0L, SEEK_SET) == 0) &&
  94             (write(fd, p, sz) == sz)) {
  95                 (void) free(p);
  96                 return (sz);
  97         }
  98         _elf_seterr(EIO_WRITE, errno);
  99         return (0);
 100 }