libconv/common/lddstub.c

	lddstub.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
#pragma ident   "%Z%%M% %I% %E% SMI"


#include    <unistd.h>
#include    <strings.h>
#include    <limits.h>
#include    <dlfcn.h>
#include    "_conv.h"
#include    "lddstub_msg.h"

static char orgstub[PATH_MAX];
static char orgstub64[PATH_MAX];
static int  orgflag;
static int  orgflag64;

#ifdef NEED_OWN_STRLCAT
/*
 * Appends src to the dstsize buffer at dst. The append will never
 * overflow the destination buffer and the buffer will always be null
 * terminated. Never reference beyond &bst[dstsize-1] when computing
 * the length of the pre-existing string.
 */
size_t
strlcat(char *dst, const char *src, size_t dstsize)
{
    char *df = dst;
    size_t left = dstsize;
    size_t l1;
    size_t l2 = strlen(src);
    size_t copied;

    while (left-- != 0 && *df != '\0')
        df++;
    l1 = df - dst;
    if (dstsize == l1)
        return (l1 + l2);

    copied = l1 + l2 >= dstsize ? dstsize - l1 - 1 : l2;
    memcpy(dst + l1, src, copied);
    dst[l1+copied] = '\0';
    return (l1 + l2);
}
#endif

static int
originlddstub(char *buffer, const char *orgfile)
{
    int len;

    if (dlinfo(RTLD_SELF, RTLD_DI_ORIGIN, (void *)buffer) == -1)
        return (-1);
    if (strlcat(buffer, orgfile, PATH_MAX) >= PATH_MAX)
        return (-1);
    if ((len = resolvepath(buffer, buffer, (PATH_MAX - 1))) == -1)
        return (-1);
    buffer[len] = '\0';
    if (access(orgstub, X_OK) == -1)
        return (-1);

    return (0);
}

/*
 * Determine what lddstub to run.
 */
const char *
conv_lddstub(int class)
{
    const char *stub;

    /*
     * Establish defaults.
     */
    if (class == ELFCLASS32)
        stub = MSG_ORIG(MSG_PTH_LDDSTUB);
    else
        stub = MSG_ORIG(MSG_PTH_LDDSTUB_64);

    /*
     * Provided we're not secure, determine lddstub's location from our
     * own origin.
     */
    if (geteuid()) {
        if ((class == ELFCLASS32) && (orgflag != -1)) {
            if (orgflag == 0) {
                if ((orgflag = originlddstub(orgstub,
                    MSG_ORIG(MSG_ORG_LDDSTUB))) == -1)
                    return (stub);
            }
            stub = (const char *)orgstub;
        }
        if ((class == ELFCLASS64) && (orgflag64 != -1)) {
            if (orgflag64 == 0) {
                if ((orgflag64 = originlddstub(orgstub64,
                    MSG_ORIG(MSG_ORG_LDDSTUB_64))) == -1)
                    return (stub);
            }
            stub = (const char *)orgstub64;
        }
    }
    return (stub);
}