gnu/usr.bin/gdb/kgdb/kld.c

   1 /*
   2  * Copyright (c) 2004 Marcel Moolenaar
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/stat.h>
  32 #include <fcntl.h>
  33 #include <kvm.h>
  34 #include <libgen.h>
  35
  36 #include <defs.h>
  37 #include <command.h>
  38 #include <completer.h>
  39 #include <environ.h>
  40 #include <exec.h>
  41 #include <frame-unwind.h>
  42 #include <inferior.h>
  43 #include <objfiles.h>
  44 #include <gdbcore.h>
  45 #include <language.h>
  46 #include <solist.h>
  47
  48 #include "kgdb.h"
  49
  50 struct lm_info {
  51         CORE_ADDR base_address;
  52 };
  53
  54 /* Offsets of fields in linker_file structure. */
  55 static CORE_ADDR off_address, off_filename, off_pathname, off_next;
  56
  57 /* KVA of 'linker_path' which corresponds to the kern.module_path sysctl .*/
  58 static CORE_ADDR module_path_addr;
  59 static CORE_ADDR linker_files_addr;
  60 static CORE_ADDR kernel_file_addr;
  61
  62 static struct target_so_ops kld_so_ops;
  63
  64 static int
  65 kld_ok (char *path)
  66 {
  67         struct stat sb;
  68
  69         if (stat(path, &sb) == 0 && S_ISREG(sb.st_mode))
  70                 return (1);
  71         return (0);
  72 }
  73
  74 /*
  75  * Look for a matching file checking for debug suffixes before the raw file:
  76  * - filename + ".debug" (e.g. foo.ko.debug)
  77  * - filename (e.g. foo.ko)
  78  */
  79 static const char *kld_suffixes[] = {
  80         ".debug",
  81         "",
  82         NULL
  83 };
  84
  85 static int
  86 check_kld_path (char *path, size_t path_size)
  87 {
  88         const char **suffix;
  89         char *ep;
  90
  91         ep = path + strlen(path);
  92         suffix = kld_suffixes;
  93         while (*suffix != NULL) {
  94                 if (strlcat(path, *suffix, path_size) < path_size) {
  95                         if (kld_ok(path))
  96                                 return (1);
  97                 }
  98
  99                 /* Restore original path to remove suffix. */
 100                 *ep = '\0';
 101                 suffix++;
 102         }
 103         return (0);
 104 }
 105
 106 /*
 107  * Try to find the path for a kld by looking in the kernel's directory and
 108  * in the various paths in the module path.
 109  */
 110 static int
 111 find_kld_path (char *filename, char *path, size_t path_size)
 112 {
 113         char *module_path;
 114         char *kernel_dir, *module_dir, *cp;
 115         int error;
 116
 117         if (exec_bfd) {
 118                 kernel_dir = dirname(bfd_get_filename(exec_bfd));
 119                 if (kernel_dir != NULL) {
 120                         snprintf(path, path_size, "%s/%s", kernel_dir,
 121                             filename);
 122                         if (check_kld_path(path, path_size))
 123                                 return (1);
 124                 }
 125         }
 126         if (module_path_addr != 0) {
 127                 target_read_string(module_path_addr, &module_path, PATH_MAX,
 128                     &error);
 129                 if (error == 0) {
 130                         make_cleanup(xfree, module_path);
 131                         cp = module_path;
 132                         while ((module_dir = strsep(&cp, ";")) != NULL) {
 133                                 snprintf(path, path_size, "%s/%s", module_dir,
 134                                     filename);
 135                                 if (check_kld_path(path, path_size))
 136                                         return (1);
 137                         }
 138                 }
 139         }
 140         return (0);
 141 }
 142
 143 /*
 144  * Read a kernel pointer given a KVA in 'address'.
 145  */
 146 static CORE_ADDR
 147 read_pointer (CORE_ADDR address)
 148 {
 149         CORE_ADDR value;
 150
 151         if (target_read_memory(address, (char *)&value, TARGET_PTR_BIT / 8) !=
 152             0)
 153                 return (0);
 154         return (extract_unsigned_integer(&value, TARGET_PTR_BIT / 8));
 155 }
 156
 157 /*
 158  * Try to find this kld in the kernel linker's list of linker files.
 159  */
 160 static int
 161 find_kld_address (char *arg, CORE_ADDR *address)
 162 {
 163         CORE_ADDR kld;
 164         char *kld_filename;
 165         char *filename;
 166         int error;
 167
 168         if (linker_files_addr == 0 || off_address == 0 || off_filename == 0 ||
 169             off_next == 0)
 170                 return (0);
 171
 172         filename = basename(arg);
 173         for (kld = read_pointer(linker_files_addr); kld != 0;
 174              kld = read_pointer(kld + off_next)) {
 175                 /* Try to read this linker file's filename. */
 176                 target_read_string(read_pointer(kld + off_filename),
 177                     &kld_filename, PATH_MAX, &error);
 178                 if (error)
 179                         continue;
 180
 181                 /* Compare this kld's filename against our passed in name. */
 182                 if (strcmp(kld_filename, filename) != 0) {
 183                         xfree(kld_filename);
 184                         continue;
 185                 }
 186                 xfree(kld_filename);
 187
 188                 /*
 189                  * We found a match, use its address as the base
 190                  * address if we can read it.
 191                  */
 192                 *address = read_pointer(kld + off_address);
 193                 if (*address == 0)
 194                         return (0);
 195                 return (1);
 196         }
 197         return (0);
 198 }
 199
 200 static void
 201 load_kld (char *path, CORE_ADDR base_addr, int from_tty)
 202 {
 203         struct section_addr_info *sap;
 204         struct section_table *sections = NULL, *sections_end = NULL, *s;
 205         struct cleanup *cleanup;
 206         bfd *bfd;
 207         int i;
 208
 209         /* Open the kld. */
 210         bfd = bfd_openr(path, gnutarget);
 211         if (bfd == NULL)
 212                 error("\"%s\": can't open: %s", path,
 213                     bfd_errmsg(bfd_get_error()));
 214         cleanup = make_cleanup_bfd_close(bfd);
 215
 216         if (!bfd_check_format(bfd, bfd_object))
 217                 error("\%s\": not an object file", path);
 218
 219         /* Make sure we have a .text section. */
 220         if (bfd_get_section_by_name (bfd, ".text") == NULL)
 221                 error("\"%s\": can't find text section", path);
 222
 223         /* Build a section table from the bfd and relocate the sections. */
 224         if (build_section_table (bfd, &sections, &sections_end))
 225                 error("\"%s\": can't find file sections", path);
 226         cleanup = make_cleanup(xfree, sections);
 227         for (s = sections; s < sections_end; s++) {
 228                 s->addr += base_addr;
 229                 s->endaddr += base_addr;
 230         }
 231
 232         /* Build a section addr info to pass to symbol_file_add(). */
 233         sap = build_section_addr_info_from_section_table (sections,
 234             sections_end);
 235         cleanup = make_cleanup((make_cleanup_ftype *)free_section_addr_info,
 236             sap);
 237
 238         printf_unfiltered("add symbol table from file \"%s\" at\n", path);
 239         for (i = 0; i < sap->num_sections; i++)
 240                 printf_unfiltered("\t%s_addr = %s\n", sap->other[i].name,
 241                     local_hex_string(sap->other[i].addr));
 242
 243         if (from_tty && (!query("%s", "")))
 244                 error("Not confirmed.");
 245
 246         symbol_file_add(path, from_tty, sap, 0, OBJF_USERLOADED);
 247
 248         do_cleanups(cleanup);
 249 }
 250
 251 static void
 252 kgdb_add_kld_cmd (char *arg, int from_tty)
 253 {
 254         char path[PATH_MAX];
 255         CORE_ADDR base_addr;
 256
 257         if (!exec_bfd)
 258                 error("No kernel symbol file");
 259
 260         /* Try to open the raw path to handle absolute paths first. */
 261         snprintf(path, sizeof(path), "%s", arg);
 262         if (!check_kld_path(path, sizeof(path))) {
 263
 264                 /*
 265                  * If that didn't work, look in the various possible
 266                  * paths for the module.
 267                  */
 268                 if (!find_kld_path(arg, path, sizeof(path))) {
 269                         error("Unable to locate kld");
 270                         return;
 271                 }
 272         }
 273
 274         if (!find_kld_address(arg, &base_addr)) {
 275                 error("Unable to find kld in kernel");
 276                 return;
 277         }
 278
 279         load_kld(path, base_addr, from_tty);
 280
 281         reinit_frame_cache();
 282 }
 283
 284 static void
 285 kld_relocate_section_addresses (struct so_list *so, struct section_table *sec)
 286 {
 287
 288         sec->addr += so->lm_info->base_address;
 289         sec->endaddr += so->lm_info->base_address;
 290 }
 291
 292 static void
 293 kld_free_so (struct so_list *so)
 294 {
 295
 296         xfree(so->lm_info);
 297 }
 298
 299 static void
 300 kld_clear_solib (void)
 301 {
 302 }
 303
 304 static void
 305 kld_solib_create_inferior_hook (void)
 306 {
 307 }
 308
 309 static void
 310 kld_special_symbol_handling (void)
 311 {
 312 }
 313
 314 static struct so_list *
 315 kld_current_sos (void)
 316 {
 317         struct so_list *head, **prev, *new;
 318         CORE_ADDR kld, kernel;
 319         char *path;
 320         int error;
 321
 322         if (linker_files_addr == 0 || kernel_file_addr == 0 ||
 323             off_address == 0 || off_filename == 0 || off_next == 0)
 324                 return (NULL);
 325
 326         head = NULL;
 327         prev = &head;
 328
 329         /*
 330          * Walk the list of linker files creating so_list entries for
 331          * each non-kernel file.
 332          */
 333         kernel = read_pointer(kernel_file_addr);
 334         for (kld = read_pointer(linker_files_addr); kld != 0;
 335              kld = read_pointer(kld + off_next)) {
 336                 /* Skip the main kernel file. */
 337                 if (kld == kernel)
 338                         continue;
 339
 340                 new = xmalloc(sizeof(*new));
 341                 memset(new, 0, sizeof(*new));
 342
 343                 new->lm_info = xmalloc(sizeof(*new->lm_info));
 344                 new->lm_info->base_address = 0;
 345
 346                 /* Read the base filename and store it in so_original_name. */
 347                 target_read_string(read_pointer(kld + off_filename),
 348                     &path, sizeof(new->so_original_name), &error);
 349                 if (error != 0) {
 350                         warning("kld_current_sos: Can't read filename: %s\n",
 351                             safe_strerror(error));
 352                         free_so(new);
 353                         continue;
 354                 }
 355                 strlcpy(new->so_original_name, path,
 356                     sizeof(new->so_original_name));
 357                 xfree(path);
 358
 359                 /*
 360                  * Try to read the pathname (if it exists) and store
 361                  * it in so_name.
 362                  */
 363                 if (off_pathname != 0) {
 364                         target_read_string(read_pointer(kld + off_pathname),
 365                             &path, sizeof(new->so_name), &error);
 366                         if (error != 0) {
 367                                 warning(
 368                     "kld_current_sos: Can't read pathname for \"%s\": %s\n",
 369                                     new->so_original_name,
 370                                     safe_strerror(error));
 371                                 strlcpy(new->so_name, new->so_original_name,
 372                                     sizeof(new->so_name));
 373                         } else {
 374                                 strlcpy(new->so_name, path,
 375                                     sizeof(new->so_name));
 376                                 xfree(path);
 377                         }
 378                 } else
 379                         strlcpy(new->so_name, new->so_original_name,
 380                             sizeof(new->so_name));
 381
 382                 /* Read this kld's base address. */
 383                 new->lm_info->base_address = read_pointer(kld + off_address);
 384                 if (new->lm_info->base_address == 0) {
 385                         warning(
 386                             "kld_current_sos: Invalid address for kld \"%s\"",
 387                             new->so_original_name);
 388                         free_so(new);
 389                         continue;
 390                 }
 391
 392                 /* Append to the list. */
 393                 *prev = new;
 394                 prev = &new->next;
 395         }
 396
 397         return (head);
 398 }
 399
 400 static int
 401 kld_open_symbol_file_object (void *from_ttyp)
 402 {
 403
 404         return (0);
 405 }
 406
 407 static int
 408 kld_in_dynsym_resolve_code (CORE_ADDR pc)
 409 {
 410
 411         return (0);
 412 }
 413
 414 static int
 415 kld_find_and_open_solib (char *solib, unsigned o_flags, char **temp_pathname)
 416 {
 417         char path[PATH_MAX];
 418         int fd;
 419
 420         *temp_pathname = NULL;
 421         if (!find_kld_path(solib, path, sizeof(path))) {
 422                 errno = ENOENT;
 423                 return (-1);
 424         }
 425         fd = open(path, o_flags, 0);
 426         if (fd >= 0)
 427                 *temp_pathname = xstrdup(path);
 428         return (fd);
 429 }
 430
 431 void
 432 kld_new_objfile (struct objfile *objfile)
 433 {
 434
 435         if (!have_partial_symbols())
 436                 return;
 437
 438         /*
 439          * Compute offsets of relevant members in struct linker_file
 440          * and the addresses of global variables.  Don't warn about
 441          * kernels that don't have 'pathname' in the linker_file
 442          * struct since 6.x kernels don't have it.
 443          */
 444         off_address = kgdb_parse("&((struct linker_file *)0)->address");
 445         off_filename = kgdb_parse("&((struct linker_file *)0)->filename");
 446         off_pathname = kgdb_parse_quiet("&((struct linker_file *)0)->pathname");
 447         off_next = kgdb_parse("&((struct linker_file *)0)->link.tqe_next");
 448         module_path_addr = kgdb_parse("linker_path");
 449         linker_files_addr = kgdb_parse("&linker_files.tqh_first");
 450         kernel_file_addr = kgdb_parse("&linker_kernel_file");
 451 }
 452
 453 static int
 454 load_klds_stub (void *arg)
 455 {
 456
 457         SOLIB_ADD(NULL, 1, &current_target, auto_solib_add);
 458         return (0);
 459 }
 460
 461 void
 462 kld_init (void)
 463 {
 464
 465         catch_errors(load_klds_stub, NULL, NULL, RETURN_MASK_ALL);
 466 }
 467
 468 void
 469 initialize_kld_target(void)
 470 {
 471         struct cmd_list_element *c;
 472
 473         kld_so_ops.relocate_section_addresses = kld_relocate_section_addresses;
 474         kld_so_ops.free_so = kld_free_so;
 475         kld_so_ops.clear_solib = kld_clear_solib;
 476         kld_so_ops.solib_create_inferior_hook = kld_solib_create_inferior_hook;
 477         kld_so_ops.special_symbol_handling = kld_special_symbol_handling;
 478         kld_so_ops.current_sos = kld_current_sos;
 479         kld_so_ops.open_symbol_file_object = kld_open_symbol_file_object;
 480         kld_so_ops.in_dynsym_resolve_code = kld_in_dynsym_resolve_code;
 481         kld_so_ops.find_and_open_solib = kld_find_and_open_solib;
 482
 483         current_target_so_ops = &kld_so_ops;
 484
 485         c = add_com("add-kld", class_files, kgdb_add_kld_cmd,
 486            "Usage: add-kld FILE\n\
 487 Load the symbols from the kernel loadable module FILE.");
 488         set_cmd_completer(c, filename_completer);
 489 }