1 /* Standard libdwfl callbacks for debugging a live Linux process. 2 Copyright (C) 2005-2010 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 <inttypes.h> 52 #include <sys/types.h> 53 #include <errno.h> 54 #include <stdio.h> 55 #include <stdio_ext.h> 56 #include <stdbool.h> 57 #include <string.h> 58 #include <stdlib.h> 59 #include <fcntl.h> 60 #include <unistd.h> 61 #include <assert.h> 62 #include <endian.h> 63 64 65 #define PROCMAPSFMT "/proc/%d/maps" 66 #define PROCMEMFMT "/proc/%d/mem" 67 #define PROCAUXVFMT "/proc/%d/auxv" 68 69 70 /* Search /proc/PID/auxv for the AT_SYSINFO_EHDR tag. */ 71 72 static int 73 grovel_auxv (pid_t pid, Dwfl *dwfl, GElf_Addr *sysinfo_ehdr) 74 { 75 char *fname; 76 if (asprintf (&fname, PROCAUXVFMT, pid) < 0) 77 return ENOMEM; 78 79 int fd = open64 (fname, O_RDONLY); 80 free (fname); 81 if (fd < 0) 82 return errno == ENOENT ? 0 : errno; 83 84 ssize_t nread; 85 do 86 { 87 union 88 { 89 char buffer[sizeof (long int) * 2 * 64]; 90 Elf64_auxv_t a64[sizeof (long int) * 2 * 64 / sizeof (Elf64_auxv_t)]; 91 Elf32_auxv_t a32[sizeof (long int) * 2 * 32 / sizeof (Elf32_auxv_t)]; 92 } d; 93 nread = read (fd, &d, sizeof d); 94 if (nread > 0) 95 { 96 switch (sizeof (long int)) 97 { 98 case 4: 99 for (size_t i = 0; (char *) &d.a32[i] < &d.buffer[nread]; ++i) 100 if (d.a32[i].a_type == AT_SYSINFO_EHDR) 101 { 102 *sysinfo_ehdr = d.a32[i].a_un.a_val; 103 if (dwfl->segment_align > 1) 104 { 105 nread = 0; 106 break; 107 } 108 } 109 else if (d.a32[i].a_type == AT_PAGESZ 110 && dwfl->segment_align <= 1) 111 dwfl->segment_align = d.a32[i].a_un.a_val; 112 break; 113 case 8: 114 for (size_t i = 0; (char *) &d.a64[i] < &d.buffer[nread]; ++i) 115 if (d.a64[i].a_type == AT_SYSINFO_EHDR) 116 { 117 *sysinfo_ehdr = d.a64[i].a_un.a_val; 118 if (dwfl->segment_align > 1) 119 { 120 nread = 0; 121 break; 122 } 123 } 124 else if (d.a64[i].a_type == AT_PAGESZ 125 && dwfl->segment_align <= 1) 126 dwfl->segment_align = d.a64[i].a_un.a_val; 127 break; 128 default: 129 abort (); 130 break; 131 } 132 } 133 } 134 while (nread > 0); 135 136 close (fd); 137 138 return nread < 0 ? errno : 0; 139 } 140 141 static int 142 proc_maps_report (Dwfl *dwfl, FILE *f, GElf_Addr sysinfo_ehdr, pid_t pid) 143 { 144 unsigned int last_dmajor = -1, last_dminor = -1; 145 uint64_t last_ino = -1; 146 char *last_file = NULL; 147 Dwarf_Addr low = 0, high = 0; 148 149 inline bool report (void) 150 { 151 if (last_file != NULL) 152 { 153 Dwfl_Module *mod = INTUSE(dwfl_report_module) (dwfl, last_file, 154 low, high); 155 free (last_file); 156 last_file = NULL; 157 if (unlikely (mod == NULL)) 158 return true; 159 } 160 return false; 161 } 162 163 char *line = NULL; 164 size_t linesz; 165 ssize_t len; 166 while ((len = getline (&line, &linesz, f)) > 0) 167 { 168 if (line[len - 1] == '\n') 169 line[len - 1] = '\0'; 170 171 Dwarf_Addr start, end, offset; 172 unsigned int dmajor, dminor; 173 uint64_t ino; 174 int nread = -1; 175 if (sscanf (line, "%" PRIx64 "-%" PRIx64 " %*s %" PRIx64 176 " %x:%x %" PRIi64 " %n", 177 &start, &end, &offset, &dmajor, &dminor, &ino, &nread) < 6 178 || nread <= 0) 179 { 180 free (line); 181 return ENOEXEC; 182 } 183 184 /* If this is the special mapping AT_SYSINFO_EHDR pointed us at, 185 report the last one and then this special one. */ 186 if (start == sysinfo_ehdr && start != 0) 187 { 188 if (report ()) 189 { 190 bad_report: 191 free (line); 192 fclose (f); 193 return -1; 194 } 195 196 low = start; 197 high = end; 198 if (asprintf (&last_file, "[vdso: %d]", (int) pid) < 0 199 || report ()) 200 goto bad_report; 201 } 202 203 char *file = line + nread + strspn (line + nread, " \t"); 204 if (file[0] == '\0' || (ino == 0 && dmajor == 0 && dminor == 0)) 205 /* This line doesn't indicate a file mapping. */ 206 continue; 207 208 if (last_file != NULL 209 && ino == last_ino && dmajor == last_dmajor && dminor == last_dminor) 210 { 211 /* This is another portion of the same file's mapping. */ 212 assert (!strcmp (last_file, file)); 213 high = end; 214 } 215 else 216 { 217 /* This is a different file mapping. Report the last one. */ 218 if (report ()) 219 goto bad_report; 220 low = start; 221 high = end; 222 last_file = strdup (file); 223 last_ino = ino; 224 last_dmajor = dmajor; 225 last_dminor = dminor; 226 } 227 } 228 free (line); 229 230 int result = ferror_unlocked (f) ? errno : feof_unlocked (f) ? 0 : ENOEXEC; 231 232 /* Report the final one. */ 233 bool lose = report (); 234 235 return result != 0 ? result : lose ? -1 : 0; 236 } 237 238 int 239 dwfl_linux_proc_maps_report (Dwfl *dwfl, FILE *f) 240 { 241 return proc_maps_report (dwfl, f, 0, 0); 242 } 243 INTDEF (dwfl_linux_proc_maps_report) 244 245 int 246 dwfl_linux_proc_report (Dwfl *dwfl, pid_t pid) 247 { 248 if (dwfl == NULL) 249 return -1; 250 251 /* We'll notice the AT_SYSINFO_EHDR address specially when we hit it. */ 252 GElf_Addr sysinfo_ehdr = 0; 253 int result = grovel_auxv (pid, dwfl, &sysinfo_ehdr); 254 if (result != 0) 255 return result; 256 257 char *fname; 258 if (asprintf (&fname, PROCMAPSFMT, pid) < 0) 259 return ENOMEM; 260 261 FILE *f = fopen (fname, "r"); 262 free (fname); 263 if (f == NULL) 264 return errno; 265 266 (void) __fsetlocking (f, FSETLOCKING_BYCALLER); 267 268 result = proc_maps_report (dwfl, f, sysinfo_ehdr, pid); 269 270 fclose (f); 271 272 return result; 273 } 274 INTDEF (dwfl_linux_proc_report) 275 276 static ssize_t 277 read_proc_memory (void *arg, void *data, GElf_Addr address, 278 size_t minread, size_t maxread) 279 { 280 const int fd = *(const int *) arg; 281 ssize_t nread = pread64 (fd, data, maxread, (off64_t) address); 282 /* Some kernels don't actually let us do this read, ignore those errors. */ 283 if (nread < 0 && (errno == EINVAL || errno == EPERM)) 284 return 0; 285 if (nread > 0 && (size_t) nread < minread) 286 nread = 0; 287 return nread; 288 } 289 290 extern Elf *elf_from_remote_memory (GElf_Addr ehdr_vma, 291 GElf_Addr *loadbasep, 292 ssize_t (*read_memory) (void *arg, 293 void *data, 294 GElf_Addr address, 295 size_t minread, 296 size_t maxread), 297 void *arg); 298 299 300 /* Dwfl_Callbacks.find_elf */ 301 302 int 303 dwfl_linux_proc_find_elf (Dwfl_Module *mod __attribute__ ((unused)), 304 void **userdata __attribute__ ((unused)), 305 const char *module_name, Dwarf_Addr base, 306 char **file_name, Elf **elfp) 307 { 308 if (module_name[0] == '/') 309 { 310 int fd = open64 (module_name, O_RDONLY); 311 if (fd >= 0) 312 { 313 *file_name = strdup (module_name); 314 if (*file_name == NULL) 315 { 316 close (fd); 317 return ENOMEM; 318 } 319 } 320 return fd; 321 } 322 323 int pid; 324 if (sscanf (module_name, "[vdso: %d]", &pid) == 1) 325 { 326 /* Special case for in-memory ELF image. */ 327 328 char *fname; 329 if (asprintf (&fname, PROCMEMFMT, pid) < 0) 330 return -1; 331 332 int fd = open64 (fname, O_RDONLY); 333 free (fname); 334 if (fd < 0) 335 return -1; 336 337 *elfp = elf_from_remote_memory (base, NULL, &read_proc_memory, &fd); 338 339 close (fd); 340 341 *file_name = NULL; 342 return -1; 343 } 344 345 abort (); 346 return -1; 347 } 348 INTDEF (dwfl_linux_proc_find_elf) 349
