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search.c
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search.c
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/* $NetBSD: search.c,v 1.21 2006/03/21 17:48:10 christos Exp $ */
/*
* Copyright 1996 Matt Thomas <matt@3am-software.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Polstra.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Dynamic linker for ELF.
*
* John Polstra <jdp@polstra.com>.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: search.c,v 1.21 2006/03/21 17:48:10 christos Exp $");
#endif /* not lint */
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <dirent.h>
#include "debug.h"
#include "rtld.h"
/*
* Data declarations.
*/
Search_Path *_rtld_invalid_paths;
static Obj_Entry *_rtld_search_library_path(const char *, size_t,
const char *, size_t, int);
static Obj_Entry *
_rtld_search_library_path(const char *name, size_t namelen,
const char *dir, size_t dirlen, int mode)
{
char pathname[MAXPATHLEN];
size_t pathnamelen;
Obj_Entry *obj;
Search_Path *sp;
pathnamelen = dirlen + 1 + namelen;
if (pathnamelen >= sizeof(pathname))
return NULL;
for (sp = _rtld_invalid_paths; sp != NULL; sp = sp->sp_next) {
if (sp->sp_pathlen == pathnamelen &&
!memcmp(name, sp->sp_path + dirlen + 1, namelen) &&
!memcmp(dir, sp->sp_path, dirlen)) {
return NULL;
}
}
(void)strncpy(pathname, dir, dirlen);
pathname[dirlen] = '/';
strcpy(pathname + dirlen + 1, name);
dbg((" Trying \"%s\"", pathname));
obj = _rtld_load_object(pathname, mode);
if (obj == NULL) {
Search_Path *path;
path = NEW(Search_Path);
path->sp_pathlen = pathnamelen;
path->sp_path = xstrdup(pathname);
path->sp_next = _rtld_invalid_paths;
_rtld_invalid_paths = path;
}
return obj;
}
/*
* Find the library with the given name, and return its full pathname.
* The returned string is dynamically allocated. Generates an error
* message and returns NULL if the library cannot be found.
*
* If the second argument is non-NULL, then it refers to an already-
* loaded shared object, whose library search path will be searched.
*/
Obj_Entry *
_rtld_load_library(const char *name, const Obj_Entry *refobj, int mode)
{
char tmperror[512], *tmperrorp;
Search_Path *sp;
const char *pathname;
int namelen;
Obj_Entry *obj;
if (strchr(name, '/') != NULL) { /* Hard coded pathname */
if (name[0] != '/' && !_rtld_trust) {
_rtld_error(
"absolute pathname required for shared object \"%s\"",
name);
return NULL;
}
pathname = name;
goto found;
}
dbg((" Searching for \"%s\" (%p)", name, refobj));
tmperrorp = dlerror();
if (tmperrorp != NULL) {
strncpy(tmperror, tmperrorp, sizeof tmperror);
tmperrorp = tmperror;
}
namelen = strlen(name);
for (sp = _rtld_paths; sp != NULL; sp = sp->sp_next)
if ((obj = _rtld_search_library_path(name, namelen,
sp->sp_path, sp->sp_pathlen, mode)) != NULL)
goto pathfound;
if (refobj != NULL)
for (sp = refobj->rpaths; sp != NULL; sp = sp->sp_next)
if ((obj = _rtld_search_library_path(name,
namelen, sp->sp_path, sp->sp_pathlen, mode)) != NULL)
goto pathfound;
for (sp = _rtld_default_paths; sp != NULL; sp = sp->sp_next)
if ((obj = _rtld_search_library_path(name, namelen,
sp->sp_path, sp->sp_pathlen, mode)) != NULL)
goto pathfound;
_rtld_error("Shared object \"%s\" not found", name);
return NULL;
pathfound:
/*
* Successfully found a library; restore the dlerror state as it was
* before _rtld_load_library() was called (any failed call to
* _rtld_search_library_path() will set the dlerror state, but if the
* library was eventually found, then the error state should not
* change.
*/
if (tmperrorp)
_rtld_error("%s", tmperror);
else
(void)dlerror();
return obj;
found:
return _rtld_load_object(pathname, mode);
}