search.c revision 1.12 
1/*	$NetBSD: search.c,v 1.12 2002/09/24 00:02:46 mycroft Exp $	 */
2
3/*
4 * Copyright 1996 Matt Thomas <matt@3am-software.com>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *      This product includes software developed by John Polstra.
18 * 4. The name of the author may not be used to endorse or promote products
19 *    derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33/*
34 * Dynamic linker for ELF.
35 *
36 * John Polstra <jdp@polstra.com>.
37 */
38
39#include <err.h>
40#include <errno.h>
41#include <fcntl.h>
42#include <stdarg.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47#include <sys/types.h>
48#include <sys/mman.h>
49#include <sys/stat.h>
50#include <dirent.h>
51
52#include "debug.h"
53#include "rtld.h"
54
55/*
56 * Data declarations.
57 */
58static Obj_Entry *_rtld_search_library_path __P((const char *, size_t,
59    const char *, size_t, int));
60
61static Obj_Entry *
62_rtld_search_library_path(name, namelen, dir, dirlen, mode)
63	const char *name;
64	size_t namelen;
65	const char *dir;
66	size_t dirlen;
67	int mode;
68{
69	char *pathname;
70	Obj_Entry *obj;
71
72	pathname = xmalloc(dirlen + 1 + namelen + 1);
73	(void)strncpy(pathname, dir, dirlen);
74	pathname[dirlen] = '/';
75	strcpy(pathname + dirlen + 1, name);
76
77	dbg(("  Trying \"%s\"", pathname));
78	obj = _rtld_load_object(pathname, mode);
79	if (obj == NULL)
80		free(pathname);
81	return obj;
82}
83
84/*
85 * Find the library with the given name, and return its full pathname.
86 * The returned string is dynamically allocated.  Generates an error
87 * message and returns NULL if the library cannot be found.
88 *
89 * If the second argument is non-NULL, then it refers to an already-
90 * loaded shared object, whose library search path will be searched.
91 */
92Obj_Entry *
93_rtld_load_library(name, refobj, mode)
94	const char *name;
95	const Obj_Entry *refobj;
96	int mode;
97{
98	Search_Path *sp;
99	char *pathname;
100	int namelen;
101	Obj_Entry *obj;
102
103	if (strchr(name, '/') != NULL) {	/* Hard coded pathname */
104		if (name[0] != '/' && !_rtld_trust) {
105			_rtld_error(
106			"Absolute pathname required for shared object \"%s\"",
107			    name);
108			return NULL;
109		}
110#ifdef SVR4_LIBDIR
111		if (strncmp(name, SVR4_LIBDIR, SVR4_LIBDIRLEN) == 0
112		    && name[SVR4_LIBDIRLEN] == '/') {	/* In "/usr/lib" */
113			/*
114			 * Map hard-coded "/usr/lib" onto our ELF library
115			 * directory.
116			 */
117			pathname = xmalloc(strlen(name) + LIBDIRLEN -
118			    SVR4_LIBDIRLEN + 1);
119			(void)strcpy(pathname, LIBDIR);
120			(void)strcpy(pathname + LIBDIRLEN, name +
121			    SVR4_LIBDIRLEN);
122			goto found;
123		}
124#endif /* SVR4_LIBDIR */
125		pathname = xstrdup(name);
126		goto found;
127	}
128	dbg((" Searching for \"%s\" (%p)", name, refobj));
129
130	namelen = strlen(name);
131
132	for (sp = _rtld_paths; sp != NULL; sp = sp->sp_next)
133		if ((obj = _rtld_search_library_path(name, namelen,
134		    sp->sp_path, sp->sp_pathlen, mode)) != NULL)
135			return obj;
136
137	if (refobj != NULL)
138		for (sp = refobj->rpaths; sp != NULL; sp = sp->sp_next)
139			if ((obj = _rtld_search_library_path(name,
140			    namelen, sp->sp_path, sp->sp_pathlen, mode)) != NULL)
141				return obj;
142
143	for (sp = _rtld_default_paths; sp != NULL; sp = sp->sp_next)
144		if ((obj = _rtld_search_library_path(name, namelen,
145		    sp->sp_path, sp->sp_pathlen, mode)) != NULL)
146			return obj;
147
148	_rtld_error("Shared object \"%s\" not found", name);
149	return NULL;
150
151found:
152	obj = _rtld_load_object(pathname, mode);
153	if (obj == NULL)
154		free(pathname);
155	return obj;
156}
157