1/* $NetBSD: search.c,v 1.27 2020/04/22 23:54:32 joerg 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 1.27 2020/04/22 23:54:32 joerg 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 */ 63static Search_Path *_rtld_invalid_paths; 64 65static Obj_Entry *_rtld_search_library_path(const char *, size_t, 66 const char *, size_t, int); 67 68static Obj_Entry * 69_rtld_search_library_path(const char *name, size_t namelen, 70 const char *dir, size_t dirlen, int flags) 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 sp->sp_path[dirlen] == '/' && 84 !memcmp(name, sp->sp_path + dirlen + 1, namelen) && 85 !memcmp(dir, sp->sp_path, dirlen)) { 86 return NULL; 87 } 88 } 89 90 memcpy(pathname, dir, dirlen); 91 pathname[dirlen] = '/'; 92 memcpy(pathname + dirlen + 1, name, namelen); 93 pathname[pathnamelen] = '\0'; 94 95 dbg((" Trying \"%s\"", pathname)); 96 obj = _rtld_load_object(pathname, flags); 97 if (obj == NULL) { 98 Search_Path *path; 99 100 path = NEW(Search_Path); 101 path->sp_pathlen = pathnamelen; 102 path->sp_path = xstrdup(pathname); 103 path->sp_next = _rtld_invalid_paths; 104 _rtld_invalid_paths = path; 105 } 106 return obj; 107} 108 109/* 110 * Find the library with the given name, and return its full pathname. 111 * The returned string is dynamically allocated. Generates an error 112 * message and returns NULL if the library cannot be found. 113 * 114 * If the second argument is non-NULL, then it refers to an already- 115 * loaded shared object, whose library search path will be searched. 116 */ 117Obj_Entry * 118_rtld_load_library(const char *name, const Obj_Entry *refobj, int flags) 119{ 120 extern char *__progname; 121 char tmperror[512], *tmperrorp; 122 Search_Path *sp; 123 const char *pathname; 124 int namelen; 125 Obj_Entry *obj; 126 127 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 128 if (name[0] != '/' && !_rtld_trust) { 129 _rtld_error( 130 "absolute pathname required for shared object \"%s\"", 131 name); 132 return NULL; 133 } 134 pathname = name; 135 goto found; 136 } 137 dbg((" Searching for \"%s\" (%p)", name, refobj)); 138 139 tmperrorp = dlerror(); 140 if (tmperrorp != NULL) { 141 strlcpy(tmperror, tmperrorp, sizeof(tmperror)); 142 tmperrorp = tmperror; 143 } 144 145 namelen = strlen(name); 146 147 for (sp = _rtld_paths; sp != NULL; sp = sp->sp_next) 148 if ((obj = _rtld_search_library_path(name, namelen, 149 sp->sp_path, sp->sp_pathlen, flags)) != NULL) 150 goto pathfound; 151 152 if (refobj != NULL) 153 for (sp = refobj->rpaths; sp != NULL; sp = sp->sp_next) 154 if ((obj = _rtld_search_library_path(name, 155 namelen, sp->sp_path, sp->sp_pathlen, flags)) != NULL) 156 goto pathfound; 157 158 for (sp = _rtld_default_paths; sp != NULL; sp = sp->sp_next) 159 if ((obj = _rtld_search_library_path(name, namelen, 160 sp->sp_path, sp->sp_pathlen, flags)) != NULL) 161 goto pathfound; 162 163 _rtld_error("%s: Shared object \"%s\" not found", 164 refobj ? refobj->path : __progname, name); 165 return NULL; 166 167pathfound: 168 /* 169 * The library has been found, but it couldn't be loaded for some 170 * reason. 171 */ 172 if (obj == OBJ_ERR) 173 return NULL; 174 /* 175 * Successfully found a library; restore the dlerror state as it was 176 * before _rtld_load_library() was called (any failed call to 177 * _rtld_search_library_path() will set the dlerror state, but if the 178 * library was eventually found, then the error state should not 179 * change. 180 */ 181 if (tmperrorp) 182 _rtld_error("%s", tmperror); 183 else 184 (void)dlerror(); 185 return obj; 186 187found: 188 obj = _rtld_load_object(pathname, flags); 189 if (obj == OBJ_ERR) 190 return NULL; 191 192 return obj; 193} 194 195