search.c revision 1.6
1/* $NetBSD: search.c,v 1.6 1999/10/21 21:15:04 erh 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 bool _rtld_check_library __P((const char *)); 59static char *_rtld_search_library_path __P((const char *, size_t, const char *, 60 size_t)); 61 62static bool 63_rtld_check_library(pathname) 64 const char *pathname; 65{ 66 struct stat mystat; 67 Elf_Ehdr ehdr; 68 int fd; 69 70 if (stat(pathname, &mystat) == -1 || !S_ISREG(mystat.st_mode)) 71 return false; 72 73 if ((fd = open(pathname, O_RDONLY)) == -1) 74 return false; 75 76 if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr)) 77 goto lose; 78 79 /* Elf_e_ident includes class */ 80 if (memcmp(Elf_e_ident, ehdr.e_ident, Elf_e_siz) != 0) 81 goto lose; 82 83 switch (ehdr.e_machine) { 84 ELFDEFNNAME(MACHDEP_ID_CASES) 85 default: 86 goto lose; 87 } 88 89 if (ehdr.e_ident[Elf_ei_version] != Elf_ev_current || 90 ehdr.e_version != Elf_ev_current || 91 ehdr.e_ident[Elf_ei_data] != ELFDEFNNAME(MACHDEP_ENDIANNESS) || 92 ehdr.e_type != Elf_et_dyn) 93 goto lose; 94 95 close(fd); 96 return true; 97 98lose: 99 close(fd); 100 return false; 101} 102 103 104static char * 105_rtld_search_library_path(name, namelen, dir, dirlen) 106 const char *name; 107 size_t namelen; 108 const char *dir; 109 size_t dirlen; 110{ 111 char *pathname; 112 113 pathname = xmalloc(dirlen + 1 + namelen + 1); 114 (void)strncpy(pathname, dir, dirlen); 115 pathname[dirlen] = '/'; 116 strcpy(pathname + dirlen + 1, name); 117 118 dbg((" Trying \"%s\"", pathname)); 119 if (_rtld_check_library(pathname)) /* We found it */ 120 return pathname; 121 122 free(pathname); 123 return NULL; 124} 125 126/* 127 * Find the library with the given name, and return its full pathname. 128 * The returned string is dynamically allocated. Generates an error 129 * message and returns NULL if the library cannot be found. 130 * 131 * If the second argument is non-NULL, then it refers to an already- 132 * loaded shared object, whose library search path will be searched. 133 */ 134char * 135_rtld_find_library(name, refobj) 136 const char *name; 137 const Obj_Entry *refobj; 138{ 139 Search_Path *sp; 140 char *pathname; 141 int namelen; 142 143 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 144 if (name[0] != '/' && !_rtld_trust) { 145 _rtld_error( 146 "Absolute pathname required for shared object \"%s\"", 147 name); 148 return NULL; 149 } 150#ifdef SVR4_LIBDIR 151 if (strncmp(name, SVR4_LIBDIR, SVR4_LIBDIRLEN) == 0 152 && name[SVR4_LIBDIRLEN] == '/') { /* In "/usr/lib" */ 153 /* 154 * Map hard-coded "/usr/lib" onto our ELF library 155 * directory. 156 */ 157 pathname = xmalloc(strlen(name) + LIBDIRLEN - 158 SVR4_LIBDIRLEN + 1); 159 (void)strcpy(pathname, LIBDIR); 160 (void)strcpy(pathname + LIBDIRLEN, name + 161 SVR4_LIBDIRLEN); 162 return pathname; 163 } 164#endif /* SVR4_LIBDIR */ 165 return xstrdup(name); 166 } 167 dbg((" Searching for \"%s\" (%p)", name, refobj)); 168 169 namelen = strlen(name); 170 171 for (sp = _rtld_paths; sp != NULL; sp = sp->sp_next) 172 if ((pathname = _rtld_search_library_path(name, namelen, 173 sp->sp_path, sp->sp_pathlen)) != NULL) 174 return (pathname); 175 176 if (refobj != NULL) 177 for (sp = refobj->rpaths; sp != NULL; sp = sp->sp_next) 178 if ((pathname = _rtld_search_library_path(name, 179 namelen, sp->sp_path, sp->sp_pathlen)) != NULL) 180 return (pathname); 181 182 for (sp = _rtld_default_paths; sp != NULL; sp = sp->sp_next) 183 if ((pathname = _rtld_search_library_path(name, namelen, 184 sp->sp_path, sp->sp_pathlen)) != NULL) 185 return (pathname); 186 187#if 0 188 if ((refobj != NULL && 189 (pathname = _rtld_search_library_path(name, 190 refobj->rpath)) != NULL) || 191 (pathname = _rtld_search_library_path(name, 192 ld_library_path)) != NULL 193#ifdef SVR4_LIBDIR 194 LOSE ! 195 ||(pathname = _rtld_search_library_path(name, SVR4_LIBDIR)) != NULL 196#endif 197 ) 198 return pathname; 199#endif 200 201 _rtld_error("Shared object \"%s\" not found", name); 202 return NULL; 203} 204