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 /* ANDROID_CHANGE_BEGIN */ 209 char *fname = NULL; 210 /* ANDROID_CHANGE_END */ 211 int fd = try_open (dir, subdir, debuglink_file, &fname); 212 if (fd < 0) 213 switch (errno) 214 { 215 case ENOENT: 216 case ENOTDIR: 217 continue; 218 default: 219 /* ANDROID_CHANGE_BEGIN */ 220 #ifdef __BIONIC__ 221 free(path); 222 free(file_dirname); 223 #endif 224 /* ANDROID_CHANGE_END */ 225 return -1; 226 } 227 if (validate (mod, fd, check, debuglink_crc)) 228 { 229 *debuginfo_file_name = fname; 230 /* ANDROID_CHANGE_BEGIN */ 231 #ifdef __BIONIC__ 232 free(path); 233 free(file_dirname); 234 #endif 235 /* ANDROID_CHANGE_END */ 236 return fd; 237 } 238 free (fname); 239 close (fd); 240 } 241 242 /* ANDROID_CHANGE_BEGIN */ 243 #ifdef __BIONIC__ 244 free(path); 245 free(file_dirname); 246 #endif 247 /* ANDROID_CHANGE_END */ 248 249 /* No dice. */ 250 errno = 0; 251 return -1; 252 } 253 254 int 255 dwfl_standard_find_debuginfo (Dwfl_Module *mod, 256 void **userdata __attribute__ ((unused)), 257 const char *modname __attribute__ ((unused)), 258 GElf_Addr base __attribute__ ((unused)), 259 const char *file_name, 260 const char *debuglink_file, 261 GElf_Word debuglink_crc, 262 char **debuginfo_file_name) 263 { 264 /* First try by build ID if we have one. If that succeeds or fails 265 other than just by finding nothing, that's all we do. */ 266 const unsigned char *bits; 267 GElf_Addr vaddr; 268 if (INTUSE(dwfl_module_build_id) (mod, &bits, &vaddr) > 0) 269 { 270 int fd = INTUSE(dwfl_build_id_find_debuginfo) (mod, 271 NULL, NULL, 0, 272 NULL, NULL, 0, 273 debuginfo_file_name); 274 if (fd >= 0 || errno != 0) 275 return fd; 276 } 277 278 /* Failing that, search the path by name. */ 279 int fd = find_debuginfo_in_path (mod, file_name, 280 debuglink_file, debuglink_crc, 281 debuginfo_file_name); 282 283 if (fd < 0 && errno == 0) 284 { 285 /* If FILE_NAME is a symlink, the debug file might be associated 286 with the symlink target name instead. */ 287 288 char *canon = canonicalize_file_name (file_name); 289 if (canon != NULL && strcmp (file_name, canon)) 290 fd = find_debuginfo_in_path (mod, canon, 291 debuglink_file, debuglink_crc, 292 debuginfo_file_name); 293 free (canon); 294 } 295 296 return fd; 297 } 298 INTDEF (dwfl_standard_find_debuginfo) 299
