290 lines
7.2 KiB
C
290 lines
7.2 KiB
C
/* $NetBSD: load.c,v 1.10 1999/12/15 20:13:31 christos Exp $ */
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/*
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* Copyright 1996 John D. Polstra.
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* Copyright 1996 Matt Thomas <matt@3am-software.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Polstra.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Dynamic linker for ELF.
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*
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* John Polstra <jdp@polstra.com>.
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*/
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/mman.h>
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#include <sys/sysctl.h>
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#include <dirent.h>
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#include "debug.h"
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#include "rtld.h"
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static bool _rtld_load_by_name __P((const char *, Obj_Entry *, Needed_Entry **,
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bool));
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/*
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* Load a shared object into memory, if it is not already loaded. The
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* argument must be a string allocated on the heap. This function assumes
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* responsibility for freeing it when necessary.
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*
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* Returns a pointer to the Obj_Entry for the object. Returns NULL
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* on failure.
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*/
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Obj_Entry *
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_rtld_load_object(filepath, dodebug)
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char *filepath;
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bool dodebug;
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{
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Obj_Entry *obj;
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int fd = -1;
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struct stat sb;
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for (obj = _rtld_objlist->next; obj != NULL; obj = obj->next)
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if (strcmp(obj->path, filepath) == 0)
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break;
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/*
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* If we didn't find a match by pathname, open the file and check
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* again by device and inode. This avoids false mismatches caused
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* by multiple links or ".." in pathnames.
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*
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* To avoid a race, we open the file and use fstat() rather than
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* using stat().
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*/
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if (obj == NULL) {
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if ((fd = open(filepath, O_RDONLY)) == -1) {
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_rtld_error("Cannot open \"%s\"", filepath);
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return NULL;
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}
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if (fstat(fd, &sb) == -1) {
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_rtld_error("Cannot fstat \"%s\"", filepath);
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close(fd);
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return NULL;
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}
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for (obj = _rtld_objlist->next; obj != NULL; obj = obj->next) {
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if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) {
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close(fd);
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break;
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}
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}
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}
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if (obj == NULL) { /* First use of this object, so we must map it in */
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obj = _rtld_map_object(filepath, fd, &sb);
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(void)close(fd);
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if (obj == NULL) {
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free(filepath);
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return NULL;
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}
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obj->path = filepath;
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_rtld_digest_dynamic(obj);
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*_rtld_objtail = obj;
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_rtld_objtail = &obj->next;
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#ifdef RTLD_LOADER
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_rtld_linkmap_add(obj); /* for GDB */
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#endif
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if (dodebug) {
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dbg((" %p .. %p: %s", obj->mapbase,
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obj->mapbase + obj->mapsize - 1, obj->path));
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if (obj->textrel)
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dbg((" WARNING: %s has impure text",
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obj->path));
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}
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} else
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free(filepath);
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++obj->refcount;
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return obj;
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}
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static bool
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_rtld_load_by_name(name, obj, needed, dodebug)
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const char *name;
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Obj_Entry *obj;
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Needed_Entry **needed;
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bool dodebug;
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{
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Library_Xform *x = _rtld_xforms;
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Obj_Entry *o = NULL;
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size_t i, j;
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char *libpath;
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bool got = false;
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union {
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int i;
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char s[16];
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} val;
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if (dodebug)
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dbg(("load by name %s %p", name, x));
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for (; x; x = x->next) {
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if (strcmp(x->name, name) != 0)
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continue;
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i = sizeof(val);
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if (sysctl(x->ctl, x->ctlmax, &val, &i, NULL, 0) == -1) {
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warn("sysctl");
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break;
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}
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switch (x->ctltype[x->ctlmax - 1]) {
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case CTLTYPE_INT:
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xsnprintf(val.s, sizeof(val.s), "%d", val.i);
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break;
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case CTLTYPE_STRING:
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break;
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default:
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warnx("unsupported sysctl type %d",
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x->ctltype[x->ctlmax - 1]);
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break;
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}
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if (dodebug)
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dbg(("sysctl returns %s", val.s));
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for (i = 0; i < RTLD_MAX_ENTRY && x->entry[i].value != NULL;
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i++) {
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if (dodebug)
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dbg(("entry %ld", (unsigned long)i));
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if (strcmp(x->entry[i].value, val.s) == 0)
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break;
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}
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if (i == RTLD_MAX_ENTRY) {
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warnx("sysctl value %s not found for lib%s",
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val.s, name);
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break;
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}
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/* XXX: This can mess up debuggers, cause we lie about
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* what we loaded in the needed objects */
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for (j = 0; j < RTLD_MAX_LIBRARY &&
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x->entry[i].library[j] != NULL; j++) {
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libpath = _rtld_find_library(
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x->entry[i].library[j], obj);
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if (libpath == NULL) {
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warnx("could not load lib%s for lib%s",
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x->entry[i].library[j], name);
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continue;
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}
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o = _rtld_load_object(libpath, true);
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if (o == NULL)
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continue;
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got = true;
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if (j == 0)
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(*needed)->obj = o;
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else {
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/* make a new one and put it in the chain */
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Needed_Entry *ne = xmalloc(sizeof(*ne));
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ne->name = (*needed)->name;
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ne->obj = o;
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ne->next = (*needed)->next;
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(*needed)->next = ne;
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*needed = ne;
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}
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}
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}
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if (got)
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return true;
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libpath = _rtld_find_library(name, obj);
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if (libpath == NULL)
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return false;
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return ((*needed)->obj = _rtld_load_object(libpath, true)) != NULL;
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}
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/*
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* Given a shared object, traverse its list of needed objects, and load
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* each of them. Returns 0 on success. Generates an error message and
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* returns -1 on failure.
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*/
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int
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_rtld_load_needed_objects(first, dodebug)
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Obj_Entry *first;
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bool dodebug;
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{
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Obj_Entry *obj;
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int status = 0;
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for (obj = first; obj != NULL; obj = obj->next) {
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Needed_Entry *needed;
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for (needed = obj->needed; needed != NULL;
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needed = needed->next) {
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const char *name = obj->strtab + needed->name;
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if (!_rtld_load_by_name(name, obj, &needed, dodebug))
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status = -1; /* FIXME - cleanup */
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#ifdef RTLD_LOADER
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if (status == -1)
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return status;
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#endif
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}
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}
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return status;
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}
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#ifdef RTLD_LOADER
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int
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_rtld_preload(preload_path, dodebug)
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const char *preload_path;
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bool dodebug;
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{
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const char *path;
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char *cp, *buf;
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int status = 0;
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if (preload_path != NULL) {
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cp = buf = xstrdup(preload_path);
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while ((path = strsep(&cp, " ")) != NULL && status == 0) {
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if (_rtld_load_object(xstrdup(path), dodebug) == NULL)
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status = -1;
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else if (dodebug)
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dbg((" preloaded \"%s\"", path));
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}
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free(buf);
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}
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return (status);
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}
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#endif
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