1 /* $NetBSD: search.c,v 1.21 2006/03/21 17:48:10 christos 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 <sys/cdefs.h> 40 #ifndef lint 41 __RCSID("$NetBSD: search.c,v 1.21 2006/03/21 17:48:10 christos Exp $"); 42 #endif /* not lint */ 43 44 #include <err.h> 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <stdarg.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <unistd.h> 52 #include <sys/types.h> 53 #include <sys/mman.h> 54 #include <sys/stat.h> 55 #include <dirent.h> 56 57 #include "debug.h" 58 #include "rtld.h" 59 60 /* 61 * Data declarations. 62 */ 63 Search_Path *_rtld_invalid_paths; 64 65 static Obj_Entry *_rtld_search_library_path(const char *, size_t, 66 const char *, size_t, int); 67 68 static Obj_Entry * 69 _rtld_search_library_path(const char *name, size_t namelen, 70 const char *dir, size_t dirlen, int mode) 71 { 72 char pathname[MAXPATHLEN]; 73 size_t pathnamelen; 74 Obj_Entry *obj; 75 Search_Path *sp; 76 77 pathnamelen = dirlen + 1 + namelen; 78 if (pathnamelen >= sizeof(pathname)) 79 return NULL; 80 81 for (sp = _rtld_invalid_paths; sp != NULL; sp = sp->sp_next) { 82 if (sp->sp_pathlen == pathnamelen && 83 !memcmp(name, sp->sp_path + dirlen + 1, namelen) && 84 !memcmp(dir, sp->sp_path, dirlen)) { 85 return NULL; 86 } 87 } 88 89 (void)strncpy(pathname, dir, dirlen); 90 pathname[dirlen] = '/'; 91 strcpy(pathname + dirlen + 1, name); 92 93 dbg((" Trying \"%s\"", pathname)); 94 obj = _rtld_load_object(pathname, mode); 95 if (obj == NULL) { 96 Search_Path *path; 97 98 path = NEW(Search_Path); 99 path->sp_pathlen = pathnamelen; 100 path->sp_path = xstrdup(pathname); 101 path->sp_next = _rtld_invalid_paths; 102 _rtld_invalid_paths = path; 103 } 104 return obj; 105 } 106 107 /* 108 * Find the library with the given name, and return its full pathname. 109 * The returned string is dynamically allocated. Generates an error 110 * message and returns NULL if the library cannot be found. 111 * 112 * If the second argument is non-NULL, then it refers to an already- 113 * loaded shared object, whose library search path will be searched. 114 */ 115 Obj_Entry * 116 _rtld_load_library(const char *name, const Obj_Entry *refobj, int mode) 117 { 118 char tmperror[512], *tmperrorp; 119 Search_Path *sp; 120 const char *pathname; 121 int namelen; 122 Obj_Entry *obj; 123 124 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 125 if (name[0] != '/' && !_rtld_trust) { 126 _rtld_error( 127 "absolute pathname required for shared object \"%s\"", 128 name); 129 return NULL; 130 } 131 pathname = name; 132 goto found; 133 } 134 dbg((" Searching for \"%s\" (%p)", name, refobj)); 135 136 tmperrorp = dlerror(); 137 if (tmperrorp != NULL) { 138 strncpy(tmperror, tmperrorp, sizeof tmperror); 139 tmperrorp = tmperror; 140 } 141 142 namelen = strlen(name); 143 144 for (sp = _rtld_paths; sp != NULL; sp = sp->sp_next) 145 if ((obj = _rtld_search_library_path(name, namelen, 146 sp->sp_path, sp->sp_pathlen, mode)) != NULL) 147 goto pathfound; 148 149 if (refobj != NULL) 150 for (sp = refobj->rpaths; sp != NULL; sp = sp->sp_next) 151 if ((obj = _rtld_search_library_path(name, 152 namelen, sp->sp_path, sp->sp_pathlen, mode)) != NULL) 153 goto pathfound; 154 155 for (sp = _rtld_default_paths; sp != NULL; sp = sp->sp_next) 156 if ((obj = _rtld_search_library_path(name, namelen, 157 sp->sp_path, sp->sp_pathlen, mode)) != NULL) 158 goto pathfound; 159 160 _rtld_error("Shared object \"%s\" not found", name); 161 return NULL; 162 163 pathfound: 164 /* 165 * Successfully found a library; restore the dlerror state as it was 166 * before _rtld_load_library() was called (any failed call to 167 * _rtld_search_library_path() will set the dlerror state, but if the 168 * library was eventually found, then the error state should not 169 * change. 170 */ 171 if (tmperrorp) 172 _rtld_error("%s", tmperror); 173 else 174 (void)dlerror(); 175 return obj; 176 177 found: 178 return _rtld_load_object(pathname, mode); 179 } 180