libelf/common/output.c

	output.c revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 *  Copyright (c) 1988 AT&T
 *    All Rights Reserved
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <libelf.h>
#include <errno.h>
#include "decl.h"
#include "msg.h"

/*
 * File output
 *  These functions write output files.
 *  On SVR4 and newer systems use mmap(2).  On older systems (or on
 *  file systems that don't support mmap), use write(2).
 */


char *
_elf_outmap(int fd, size_t sz, unsigned int *pflag)
{
    char    *p;

    /*
     * Note: Some NFS implementations do not provide from enlarging a file
     * via ftruncate(), thus this may fail with ENOSUP.  In this case the
     * fall through to the calloc() mechanism will occur.
     */
    if ((!*pflag) && (ftruncate(fd, (off_t)sz) == 0) &&
        (p = mmap((char *)0, sz, PROT_READ+PROT_WRITE,
        MAP_SHARED, fd, (off_t)0)) != (char *)-1) {
        *pflag = 1;
        return (p);
    }

    *pflag = 0;

    /*
     * If mmap fails, try calloc.  Some file systems don't mmap.  Note, we
     * use calloc rather than malloc, as ld(1) assumes that the backing
     * storage it is working with is zero filled.
     */
    if ((p = (char *)calloc(1, sz)) == 0)
        _elf_seterr(EMEM_OUT, errno);
    return (p);
}


size_t
_elf_outsync(int fd, char *p, size_t sz, unsigned int flag)
{
    if (flag != 0) {
        int err;
        /*
         * The value of MS_SYNC changed from zero to non-zero
         * in SunOS 5.7.  This double call covers both cases.
         */
        if ((fd = msync(p, sz, MS_SYNC)) == -1)
            fd = msync(p, sz, 0);
        if (fd == -1)
            err = errno;
        (void) munmap(p, sz);
        if (fd == 0)
            return (sz);
        _elf_seterr(EIO_SYNC, err);
        return (0);
    }
    if ((lseek(fd, 0L, SEEK_SET) == 0) &&
        (write(fd, p, sz) == sz) && (fsync(fd) == 0)) {
        (void) free(p);
        return (sz);
    }
    _elf_seterr(EIO_WRITE, errno);
    return (0);
}