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