1 /* Standard find_debuginfo callback for libdwfl. 2 Copyright (C) 2005, 2006, 2007, 2008 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 5 Red Hat elfutils is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by the 7 Free Software Foundation; version 2 of the License. 8 9 Red Hat elfutils is distributed in the hope that it will be useful, but 10 WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 General Public License for more details. 13 14 You should have received a copy of the GNU General Public License along 15 with Red Hat elfutils; if not, write to the Free Software Foundation, 16 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 17 18 In addition, as a special exception, Red Hat, Inc. gives You the 19 additional right to link the code of Red Hat elfutils with code licensed 20 under any Open Source Initiative certified open source license 21 (http://www.opensource.org/licenses/index.php) which requires the 22 distribution of source code with any binary distribution and to 23 distribute linked combinations of the two. Non-GPL Code permitted under 24 this exception must only link to the code of Red Hat elfutils through 25 those well defined interfaces identified in the file named EXCEPTION 26 found in the source code files (the "Approved Interfaces"). The files 27 of Non-GPL Code may instantiate templates or use macros or inline 28 functions from the Approved Interfaces without causing the resulting 29 work to be covered by the GNU General Public License. Only Red Hat, 30 Inc. may make changes or additions to the list of Approved Interfaces. 31 Red Hat's grant of this exception is conditioned upon your not adding 32 any new exceptions. If you wish to add a new Approved Interface or 33 exception, please contact Red Hat. You must obey the GNU General Public 34 License in all respects for all of the Red Hat elfutils code and other 35 code used in conjunction with Red Hat elfutils except the Non-GPL Code 36 covered by this exception. If you modify this file, you may extend this 37 exception to your version of the file, but you are not obligated to do 38 so. If you do not wish to provide this exception without modification, 39 you must delete this exception statement from your version and license 40 this file solely under the GPL without exception. 41 42 Red Hat elfutils is an included package of the Open Invention Network. 43 An included package of the Open Invention Network is a package for which 44 Open Invention Network licensees cross-license their patents. No patent 45 license is granted, either expressly or impliedly, by designation as an 46 included package. Should you wish to participate in the Open Invention 47 Network licensing program, please visit www.openinventionnetwork.com 48 <http://www.openinventionnetwork.com>. */ 49 50 #include "libdwflP.h" 51 #include <stdio.h> 52 #include <fcntl.h> 53 #include <unistd.h> 54 #include "system.h" 55 56 /* Try to open64 [DIR/][SUBDIR/]DEBUGLINK, return file descriptor or -1. 57 On success, *DEBUGINFO_FILE_NAME has the malloc'd name of the open file. */ 58 static int 59 try_open (const char *dir, const char *subdir, const char *debuglink, 60 char **debuginfo_file_name) 61 { 62 char *fname; 63 if (dir == NULL && subdir == NULL) 64 { 65 fname = strdup (debuglink); 66 if (fname == NULL) 67 return -1; 68 } 69 else if ((subdir == NULL ? asprintf (&fname, "%s/%s", dir, debuglink) 70 : dir == NULL ? asprintf (&fname, "%s/%s", subdir, debuglink) 71 : asprintf (&fname, "%s/%s/%s", dir, subdir, debuglink)) < 0) 72 return -1; 73 74 int fd = TEMP_FAILURE_RETRY (open64 (fname, O_RDONLY)); 75 if (fd < 0) 76 free (fname); 77 else 78 *debuginfo_file_name = fname; 79 80 return fd; 81 } 82 83 /* Return true iff the FD's contents CRC matches DEBUGLINK_CRC. */ 84 static inline bool 85 check_crc (int fd, GElf_Word debuglink_crc) 86 { 87 uint32_t file_crc; 88 return (__libdwfl_crc32_file (fd, &file_crc) == 0 89 && file_crc == debuglink_crc); 90 } 91 92 static bool 93 validate (Dwfl_Module *mod, int fd, bool check, GElf_Word debuglink_crc) 94 { 95 /* If we have a build ID, check only that. */ 96 if (mod->build_id_len > 0) 97 { 98 /* We need to open an Elf handle on the file so we can check its 99 build ID note for validation. Backdoor the handle into the 100 module data structure since we had to open it early anyway. */ 101 mod->debug.elf = elf_begin (fd, ELF_C_READ_MMAP_PRIVATE, NULL); 102 if (likely (__libdwfl_find_build_id (mod, false, mod->debug.elf) == 2)) 103 /* Also backdoor the gratuitous flag. */ 104 mod->debug.valid = true; 105 else 106 { 107 /* A mismatch! */ 108 elf_end (mod->debug.elf); 109 mod->debug.elf = NULL; 110 mod->debug.valid = false; 111 } 112 113 return mod->debug.valid; 114 } 115 116 return !check || check_crc (fd, debuglink_crc); 117 } 118 119 static int 120 find_debuginfo_in_path (Dwfl_Module *mod, const char *file_name, 121 const char *debuglink_file, GElf_Word debuglink_crc, 122 char **debuginfo_file_name) 123 { 124 bool cancheck = debuglink_crc != (GElf_Word) 0; 125 126 const char *file_basename = file_name == NULL ? NULL : basename (file_name); 127 if (debuglink_file == NULL) 128 { 129 if (file_basename == NULL) 130 { 131 errno = 0; 132 return -1; 133 } 134 135 size_t len = strlen (file_basename); 136 char *localname = alloca (len + sizeof ".debug"); 137 memcpy (localname, file_basename, len); 138 memcpy (&localname[len], ".debug", sizeof ".debug"); 139 debuglink_file = localname; 140 cancheck = false; 141 } 142 143 /* Look for a file named DEBUGLINK_FILE in the directories 144 indicated by the debug directory path setting. */ 145 146 const Dwfl_Callbacks *const cb = mod->dwfl->callbacks; 147 /* ANDROID_CHANGE_BEGIN */ 148 #if defined(__BIONIC__) || defined(__APPLE__) 149 char *path = strdup ((cb->debuginfo_path ? *cb->debuginfo_path : NULL) 150 ?: DEFAULT_DEBUGINFO_PATH); 151 #else 152 char *path = strdupa ((cb->debuginfo_path ? *cb->debuginfo_path : NULL) 153 ?: DEFAULT_DEBUGINFO_PATH); 154 #endif 155 /* ANDROID_CHANGE_END */ 156 157 /* A leading - or + in the whole path sets whether to check file CRCs. */ 158 bool defcheck = true; 159 if (path[0] == '-' || path[0] == '+') 160 { 161 defcheck = path[0] == '+'; 162 ++path; 163 } 164 165 /* ANDROID_CHANGE_BEGIN */ 166 #if defined(__BIONIC__) || defined(__APPLE__) 167 char *file_dirname = (file_basename == file_name ? NULL 168 : strndup (file_name, file_basename - 1 - file_name)); 169 #else 170 char *file_dirname = (file_basename == file_name ? NULL 171 : strndupa (file_name, file_basename - 1 - file_name)); 172 #endif 173 /* ANDROID_CHANGE_END */ 174 char *p; 175 while ((p = strsep (&path, ":")) != NULL) 176 { 177 /* A leading - or + says whether to check file CRCs for this element. */ 178 bool check = defcheck; 179 if (*p == '+' || *p == '-') 180 check = *p++ == '+'; 181 check = check && cancheck; 182 183 const char *dir, *subdir; 184 switch (p[0]) 185 { 186 case '\0': 187 /* An empty entry says to try the main file's directory. */ 188 dir = file_dirname; 189 subdir = NULL; 190 break; 191 case '/': 192 /* An absolute path says to look there for a subdirectory 193 named by the main file's absolute directory. 194 This cannot be applied to a relative file name. */ 195 if (file_dirname == NULL || file_dirname[0] != '/') 196 continue; 197 dir = p; 198 subdir = file_dirname + 1; 199 break; 200 default: 201 /* A relative path says to try a subdirectory of that name 202 in the main file's directory. */ 203 dir = file_dirname; 204 subdir = p; 205 break; 206 } 207 208 char *fname; 209 int fd = try_open (dir, subdir, debuglink_file, &fname); 210 if (fd < 0) 211 switch (errno) 212 { 213 case ENOENT: 214 case ENOTDIR: 215 continue; 216 default: 217 /* ANDROID_CHANGE_BEGIN */ 218 #ifdef __BIONIC__ 219 free(path); 220 free(file_dirname); 221 #endif 222 /* ANDROID_CHANGE_END */ 223 return -1; 224 } 225 if (validate (mod, fd, check, debuglink_crc)) 226 { 227 *debuginfo_file_name = fname; 228 /* ANDROID_CHANGE_BEGIN */ 229 #ifdef __BIONIC__ 230 free(path); 231 free(file_dirname); 232 #endif 233 /* ANDROID_CHANGE_END */ 234 return fd; 235 } 236 free (fname); 237 close (fd); 238 } 239 240 /* ANDROID_CHANGE_BEGIN */ 241 #ifdef __BIONIC__ 242 free(path); 243 free(file_dirname); 244 #endif 245 /* ANDROID_CHANGE_END */ 246 247 /* No dice. */ 248 errno = 0; 249 return -1; 250 } 251 252 int 253 dwfl_standard_find_debuginfo (Dwfl_Module *mod, 254 void **userdata __attribute__ ((unused)), 255 const char *modname __attribute__ ((unused)), 256 GElf_Addr base __attribute__ ((unused)), 257 const char *file_name, 258 const char *debuglink_file, 259 GElf_Word debuglink_crc, 260 char **debuginfo_file_name) 261 { 262 /* First try by build ID if we have one. If that succeeds or fails 263 other than just by finding nothing, that's all we do. */ 264 const unsigned char *bits; 265 GElf_Addr vaddr; 266 if (INTUSE(dwfl_module_build_id) (mod, &bits, &vaddr) > 0) 267 { 268 int fd = INTUSE(dwfl_build_id_find_debuginfo) (mod, 269 NULL, NULL, 0, 270 NULL, NULL, 0, 271 debuginfo_file_name); 272 if (fd >= 0 || errno != 0) 273 return fd; 274 } 275 276 /* Failing that, search the path by name. */ 277 int fd = find_debuginfo_in_path (mod, file_name, 278 debuglink_file, debuglink_crc, 279 debuginfo_file_name); 280 281 if (fd < 0 && errno == 0) 282 { 283 /* If FILE_NAME is a symlink, the debug file might be associated 284 with the symlink target name instead. */ 285 286 char *canon = canonicalize_file_name (file_name); 287 if (canon != NULL && strcmp (file_name, canon)) 288 fd = find_debuginfo_in_path (mod, canon, 289 debuglink_file, debuglink_crc, 290 debuginfo_file_name); 291 free (canon); 292 } 293 294 return fd; 295 } 296 INTDEF (dwfl_standard_find_debuginfo) 297
