search.c revision 1.4
1/* $NetBSD: search.c,v 1.4 1999/03/01 16:40:07 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 <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#define CONCAT(x,y) __CONCAT(x,y) 56#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x))) 57#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y)))) 58#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE)) 59#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x))) 60 61/* 62 * Data declarations. 63 */ 64static bool _rtld_check_library __P((const char *)); 65static char *_rtld_search_library_path __P((const char *, size_t, const char *, 66 size_t)); 67 68static bool 69_rtld_check_library(pathname) 70 const char *pathname; 71{ 72 struct stat mystat; 73 Elf_Ehdr ehdr; 74 int fd; 75 76 if (stat(pathname, &mystat) == -1 || !S_ISREG(mystat.st_mode)) 77 return false; 78 79 if ((fd = open(pathname, O_RDONLY)) == -1) 80 return false; 81 82 if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr)) 83 goto lose; 84 85 /* Elf_e_ident includes class */ 86 if (memcmp(Elf_e_ident, ehdr.e_ident, Elf_e_siz) != 0) 87 goto lose; 88 89 switch (ehdr.e_machine) { 90 ELFDEFNNAME(MACHDEP_ID_CASES) 91 default: 92 goto lose; 93 } 94 95 if (ehdr.e_ident[Elf_ei_version] != Elf_ev_current || 96 ehdr.e_version != Elf_ev_current || 97 ehdr.e_ident[Elf_ei_data] != ELFDEFNNAME(MACHDEP_ENDIANNESS) || 98 ehdr.e_type != Elf_et_dyn) 99 goto lose; 100 101 close(fd); 102 return true; 103 104lose: 105 close(fd); 106 return false; 107} 108 109 110static char * 111_rtld_search_library_path(name, namelen, dir, dirlen) 112 const char *name; 113 size_t namelen; 114 const char *dir; 115 size_t dirlen; 116{ 117 char *pathname; 118 119 pathname = xmalloc(dirlen + 1 + namelen + 1); 120 (void)strncpy(pathname, dir, dirlen); 121 pathname[dirlen] = '/'; 122 strcpy(pathname + dirlen + 1, name); 123 124 dbg((" Trying \"%s\"", pathname)); 125 if (_rtld_check_library(pathname)) /* We found it */ 126 return pathname; 127 128 free(pathname); 129 return NULL; 130} 131 132/* 133 * Find the library with the given name, and return its full pathname. 134 * The returned string is dynamically allocated. Generates an error 135 * message and returns NULL if the library cannot be found. 136 * 137 * If the second argument is non-NULL, then it refers to an already- 138 * loaded shared object, whose library search path will be searched. 139 */ 140char * 141_rtld_find_library(name, refobj) 142 const char *name; 143 const Obj_Entry *refobj; 144{ 145 Search_Path *sp; 146 char *pathname; 147 int namelen; 148 149 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 150 if (name[0] != '/' && !_rtld_trust) { 151 _rtld_error( 152 "Absolute pathname required for shared object \"%s\"", 153 name); 154 return NULL; 155 } 156#ifdef SVR4_LIBDIR 157 if (strncmp(name, SVR4_LIBDIR, SVR4_LIBDIRLEN) == 0 158 && name[SVR4_LIBDIRLEN] == '/') { /* In "/usr/lib" */ 159 /* 160 * Map hard-coded "/usr/lib" onto our ELF library 161 * directory. 162 */ 163 pathname = xmalloc(strlen(name) + LIBDIRLEN - 164 SVR4_LIBDIRLEN + 1); 165 (void)strcpy(pathname, LIBDIR); 166 (void)strcpy(pathname + LIBDIRLEN, name + 167 SVR4_LIBDIRLEN); 168 return pathname; 169 } 170#endif /* SVR4_LIBDIR */ 171 return xstrdup(name); 172 } 173 dbg((" Searching for \"%s\" (%p)", name, refobj)); 174 175 namelen = strlen(name); 176 177 if (refobj != NULL) 178 for (sp = refobj->rpaths; sp != NULL; sp = sp->sp_next) 179 if ((pathname = _rtld_search_library_path(name, namelen, 180 sp->sp_path, sp->sp_pathlen)) != NULL) 181 return (pathname); 182 183 for (sp = _rtld_paths; sp != NULL; sp = sp->sp_next) 184 if ((pathname = _rtld_search_library_path(name, namelen, 185 sp->sp_path, sp->sp_pathlen)) != NULL) 186 return (pathname); 187 188#if 0 189 if ((refobj != NULL && 190 (pathname = _rtld_search_library_path(name, 191 refobj->rpath)) != NULL) || 192 (pathname = _rtld_search_library_path(name, 193 ld_library_path)) != NULL 194#ifdef SVR4_LIBDIR 195 LOSE ! 196 ||(pathname = _rtld_search_library_path(name, SVR4_LIBDIR)) != NULL 197#endif 198 ) 199 return pathname; 200#endif 201 202 _rtld_error("Shared object \"%s\" not found", name); 203 return NULL; 204} 205