search.c revision 1.19
1 /* $NetBSD: search.c,v 1.19 2004/10/22 05:39:57 skrll Exp $ */ 2 3 /* 4 * Copyright 1996 Matt Thomas <matt (at) 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 (at) polstra.com>. 37 */ 38 39 #include <sys/cdefs.h> 40 #ifndef lint 41 __RCSID("$NetBSD: search.c,v 1.19 2004/10/22 05:39:57 skrll 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; 73 size_t pathnamelen; 74 Obj_Entry *obj; 75 Search_Path *sp; 76 77 pathnamelen = dirlen + 1 + namelen; 78 79 for (sp = _rtld_invalid_paths; sp != NULL; sp = sp->sp_next) { 80 if (sp->sp_pathlen == pathnamelen && 81 !memcmp(name, sp->sp_path + dirlen + 1, namelen) && 82 !memcmp(dir, sp->sp_path, dirlen)) { 83 return NULL; 84 } 85 } 86 87 pathname = xmalloc(pathnamelen + 1); 88 (void)strncpy(pathname, dir, dirlen); 89 pathname[dirlen] = '/'; 90 strcpy(pathname + dirlen + 1, name); 91 92 dbg((" Trying \"%s\"", pathname)); 93 obj = _rtld_load_object(pathname, mode); 94 if (obj == NULL) { 95 Search_Path *path; 96 97 path = NEW(Search_Path); 98 path->sp_pathlen = pathnamelen; 99 path->sp_path = pathname; 100 path->sp_next = _rtld_invalid_paths; 101 _rtld_invalid_paths = path; 102 } 103 return obj; 104 } 105 106 /* 107 * Find the library with the given name, and return its full pathname. 108 * The returned string is dynamically allocated. Generates an error 109 * message and returns NULL if the library cannot be found. 110 * 111 * If the second argument is non-NULL, then it refers to an already- 112 * loaded shared object, whose library search path will be searched. 113 */ 114 Obj_Entry * 115 _rtld_load_library(const char *name, const Obj_Entry *refobj, int mode) 116 { 117 char tmperror[512], *tmperrorp; 118 Search_Path *sp; 119 char *pathname; 120 int namelen; 121 Obj_Entry *obj; 122 123 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 124 if (name[0] != '/' && !_rtld_trust) { 125 _rtld_error( 126 "absolute pathname required for shared object \"%s\"", 127 name); 128 return NULL; 129 } 130 pathname = xstrdup(name); 131 goto found; 132 } 133 dbg((" Searching for \"%s\" (%p)", name, refobj)); 134 135 tmperrorp = dlerror(); 136 if (tmperrorp != NULL) { 137 strncpy(tmperror, tmperrorp, sizeof tmperror); 138 tmperrorp = tmperror; 139 } 140 141 namelen = strlen(name); 142 143 for (sp = _rtld_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 goto pathfound; 147 148 if (refobj != NULL) 149 for (sp = refobj->rpaths; sp != NULL; sp = sp->sp_next) 150 if ((obj = _rtld_search_library_path(name, 151 namelen, sp->sp_path, sp->sp_pathlen, mode)) != NULL) 152 goto pathfound; 153 154 for (sp = _rtld_default_paths; sp != NULL; sp = sp->sp_next) 155 if ((obj = _rtld_search_library_path(name, namelen, 156 sp->sp_path, sp->sp_pathlen, mode)) != NULL) 157 goto pathfound; 158 159 _rtld_error("Shared object \"%s\" not found", name); 160 return NULL; 161 162 pathfound: 163 /* 164 * Successfully found a library; restore the dlerror state as it was 165 * before _rtld_load_library() was called (any failed call to 166 * _rtld_search_library_path() will set the dlerror state, but if the 167 * library was eventually found, then the error state should not 168 * change. 169 */ 170 if (tmperrorp) 171 _rtld_error("%s", tmperror); 172 else 173 (void)dlerror(); 174 return obj; 175 176 found: 177 obj = _rtld_load_object(pathname, mode); 178 if (obj == NULL) 179 free(pathname); 180 return obj; 181 } 182
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