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  * $FreeBSD: src/gnu/usr.bin/gdb/kgdb/kld.c,v 1.11 2008/10/02 20:42:10 jhb Exp $
  27  */
  28
  29 #include <sys/param.h>
  30 #include <sys/stat.h>
  31 #include <fcntl.h>
  32 #include <kvm.h>
  33 #include <libgen.h>
  34
  35 #include <defs.h>
  36 #include <command.h>
  37 #include <completer.h>
  38 #include <environ.h>
  39 #include <exec.h>
  40 #include <frame-unwind.h>
  41 #include <inferior.h>
  42 #include <objfiles.h>
  43 #include <gdbcore.h>
  44 #include <language.h>
  45 #include <solist.h>
  46 #include <arch-utils.h>
  47 #include <solib.h>
  48 #include <exceptions.h>
  49 #include <observer.h>
  50
  51 #include "kgdb.h"
  52
  53 struct lm_info {
  54         CORE_ADDR base_address;
  55 };
  56
  57 /* Offsets of fields in linker_file structure. */
  58 static CORE_ADDR off_address, off_filename, off_pathname, off_next;
  59
  60 /* KVA of 'linker_path' which corresponds to the kern.module_path sysctl .*/
  61 static CORE_ADDR module_path_addr;
  62 static CORE_ADDR linker_files_addr;
  63 static CORE_ADDR kernel_file_addr;
  64
  65 static struct target_so_ops kld_so_ops;
  66
  67 static int
  68 kld_ok (char *path)
  69 {
  70         struct stat sb;
  71
  72         if (stat(path, &sb) == 0 && S_ISREG(sb.st_mode))
  73                 return (1);
  74         return (0);
  75 }
  76
  77 /*
  78  * Look for a matching file checking for debug suffixes before the raw file:
  79  * - filename + ".debug" (e.g. foo.ko.debug)
  80  * - filename (e.g. foo.ko)
  81  */
  82 static const char *kld_suffixes[] = {
  83         ".debug",
  84         "",
  85         NULL
  86 };
  87
  88 static int
  89 check_kld_path (char *path, size_t path_size)
  90 {
  91         const char **suffix;
  92         char *ep;
  93
  94         ep = path + strlen(path);
  95         suffix = kld_suffixes;
  96         while (*suffix != NULL) {
  97                 if (strlcat(path, *suffix, path_size) < path_size) {
  98                         if (kld_ok(path))
  99                                 return (1);
 100                 }
 101
 102                 /* Restore original path to remove suffix. */
 103                 *ep = '\0';
 104                 suffix++;
 105         }
 106         return (0);
 107 }
 108
 109 /*
 110  * Try to find the path for a kld by looking in the kernel's directory and
 111  * in the various paths in the module path.
 112  */
 113 static int
 114 find_kld_path (char *filename, char *path, size_t path_size)
 115 {
 116         char *module_path;
 117         char *kernel_dir, *module_dir, *cp;
 118         int error;
 119
 120         if (exec_bfd) {
 121                 kernel_dir = dirname(bfd_get_filename(exec_bfd));
 122                 if (kernel_dir != NULL) {
 123                         snprintf(path, path_size, "%s/%s", kernel_dir,
 124                             filename);
 125                         if (check_kld_path(path, path_size))
 126                                 return (1);
 127                 }
 128         }
 129         if (module_path_addr != 0) {
 130                 target_read_string(module_path_addr, &module_path, PATH_MAX,
 131                     &error);
 132                 if (error == 0) {
 133                         make_cleanup(xfree, module_path);
 134                         cp = module_path;
 135                         while ((module_dir = strsep(&cp, ";")) != NULL) {
 136                                 snprintf(path, path_size, "%s/%s", module_dir,
 137                                     filename);
 138                                 if (check_kld_path(path, path_size))
 139                                         return (1);
 140                         }
 141                 }
 142         }
 143         return (0);
 144 }
 145
 146 /*
 147  * Read a kernel pointer given a KVA in 'address'.
 148  */
 149 static CORE_ADDR
 150 read_pointer (CORE_ADDR address)
 151 {
 152         struct gdbarch *arch = get_current_arch();
 153         enum bfd_endian byte_order = gdbarch_byte_order(arch);
 154         gdb_byte buf[sizeof(ULONGEST)];
 155         int ptrsz;
 156
 157         ptrsz = gdbarch_ptr_bit(arch) / 8;
 158
 159         if (target_read_memory(address, buf, ptrsz) != 0)
 160                 return (0);
 161         return (extract_unsigned_integer(buf, ptrsz, byte_order));
 162 }
 163
 164 /*
 165  * Try to find this kld in the kernel linker's list of linker files.
 166  */
 167 static int
 168 find_kld_address (char *arg, CORE_ADDR *address)
 169 {
 170         CORE_ADDR kld;
 171         char *kld_filename;
 172         char *filename;
 173         int error;
 174
 175         if (linker_files_addr == 0 || off_address == 0 || off_filename == 0 ||
 176             off_next == 0)
 177                 return (0);
 178
 179         filename = basename(arg);
 180         for (kld = read_pointer(linker_files_addr); kld != 0;
 181              kld = read_pointer(kld + off_next)) {
 182                 /* Try to read this linker file's filename. */
 183                 target_read_string(read_pointer(kld + off_filename),
 184                     &kld_filename, PATH_MAX, &error);
 185                 if (error)
 186                         continue;
 187
 188                 /* Compare this kld's filename against our passed in name. */
 189                 if (strcmp(kld_filename, filename) != 0) {
 190                         xfree(kld_filename);
 191                         continue;
 192                 }
 193                 xfree(kld_filename);
 194
 195                 /*
 196                  * We found a match, use its address as the base
 197                  * address if we can read it.
 198                  */
 199                 *address = read_pointer(kld + off_address);
 200                 if (*address == 0)
 201                         return (0);
 202                 return (1);
 203         }
 204         return (0);
 205 }
 206
 207 static void
 208 load_kld (char *path, CORE_ADDR base_addr, int from_tty)
 209 {
 210         struct section_addr_info *sap;
 211         struct target_section *sections = NULL, *sections_end = NULL, *s;
 212         struct cleanup *cleanup;
 213         bfd *bfd;
 214         int i;
 215
 216         /* Open the kld. */
 217         bfd = bfd_openr(path, gnutarget);
 218         if (bfd == NULL)
 219                 error("\"%s\": can't open: %s", path,
 220                     bfd_errmsg(bfd_get_error()));
 221         cleanup = make_cleanup_bfd_close(bfd);
 222
 223         if (!bfd_check_format(bfd, bfd_object))
 224                 error("\%s\": not an object file", path);
 225
 226         /* Make sure we have a .text section. */
 227         if (bfd_get_section_by_name (bfd, ".text") == NULL)
 228                 error("\"%s\": can't find text section", path);
 229
 230         /* Build a section table from the bfd and relocate the sections. */
 231         if (build_section_table (bfd, &sections, &sections_end))
 232                 error("\"%s\": can't find file sections", path);
 233         cleanup = make_cleanup(xfree, sections);
 234         for (s = sections; s < sections_end; s++) {
 235                 s->addr += base_addr;
 236                 s->endaddr += base_addr;
 237         }
 238
 239         /* Build a section addr info to pass to symbol_file_add(). */
 240         sap = build_section_addr_info_from_section_table (sections,
 241             sections_end);
 242         cleanup = make_cleanup((make_cleanup_ftype *)free_section_addr_info,
 243             sap);
 244
 245         printf_unfiltered("add symbol table from file \"%s\" at\n", path);
 246         for (i = 0; i < sap->num_sections; i++)
 247                 printf_unfiltered("\t%s_addr = %s\n", sap->other[i].name,
 248                     hex_string(sap->other[i].addr));
 249
 250         if (from_tty && (!query("%s", "")))
 251                 error("Not confirmed.");
 252
 253         symbol_file_add(path, from_tty ? SYMFILE_VERBOSE : 0, sap, OBJF_USERLOADED);
 254
 255         do_cleanups(cleanup);
 256 }
 257
 258 static void
 259 kgdb_add_kld_cmd (char *arg, int from_tty)
 260 {
 261         char path[PATH_MAX];
 262         CORE_ADDR base_addr;
 263
 264         if (!exec_bfd)
 265                 error("No kernel symbol file");
 266
 267         /* Try to open the raw path to handle absolute paths first. */
 268         snprintf(path, sizeof(path), "%s", arg);
 269         if (!check_kld_path(path, sizeof(path))) {
 270
 271                 /*
 272                  * If that didn't work, look in the various possible
 273                  * paths for the module.
 274                  */
 275                 if (!find_kld_path(arg, path, sizeof(path))) {
 276                         error("Unable to locate kld");
 277                         return;
 278                 }
 279         }
 280
 281         if (!find_kld_address(arg, &base_addr)) {
 282                 error("Unable to find kld in kernel");
 283                 return;
 284         }
 285
 286         load_kld(path, base_addr, from_tty);
 287
 288         reinit_frame_cache();
 289 }
 290
 291 static void
 292 kld_relocate_section_addresses (struct so_list *so, struct target_section *sec)
 293 {
 294
 295         sec->addr += so->lm_info->base_address;
 296         sec->endaddr += so->lm_info->base_address;
 297 }
 298
 299 static void
 300 kld_free_so (struct so_list *so)
 301 {
 302
 303         xfree(so->lm_info);
 304 }
 305
 306 static void
 307 kld_clear_solib (void)
 308 {
 309 }
 310
 311 static void
 312 kld_solib_create_inferior_hook (void)
 313 {
 314 }
 315
 316 static void
 317 kld_special_symbol_handling (void)
 318 {
 319 }
 320
 321 static struct so_list *
 322 kld_current_sos (void)
 323 {
 324         struct so_list *head, **prev, *new;
 325         CORE_ADDR kld, kernel;
 326         char *path;
 327         int error;
 328
 329         if (linker_files_addr == 0 || kernel_file_addr == 0 ||
 330             off_address == 0 || off_filename == 0 || off_next == 0)
 331                 return (NULL);
 332
 333         head = NULL;
 334         prev = &head;
 335
 336         /*
 337          * Walk the list of linker files creating so_list entries for
 338          * each non-kernel file.
 339          */
 340         kernel = read_pointer(kernel_file_addr);
 341         for (kld = read_pointer(linker_files_addr); kld != 0;
 342              kld = read_pointer(kld + off_next)) {
 343                 /* Skip the main kernel file. */
 344                 if (kld == kernel)
 345                         continue;
 346
 347                 new = xmalloc(sizeof(*new));
 348                 memset(new, 0, sizeof(*new));
 349
 350                 new->lm_info = xmalloc(sizeof(*new->lm_info));
 351                 new->lm_info->base_address = 0;
 352
 353                 /* Read the base filename and store it in so_original_name. */
 354                 target_read_string(read_pointer(kld + off_filename),
 355                     &path, sizeof(new->so_original_name), &error);
 356                 if (error != 0) {
 357                         warning("kld_current_sos: Can't read filename: %s\n",
 358                             safe_strerror(error));
 359                         free_so(new);
 360                         continue;
 361                 }
 362                 strlcpy(new->so_original_name, path,
 363                     sizeof(new->so_original_name));
 364                 xfree(path);
 365
 366                 /*
 367                  * Try to read the pathname (if it exists) and store
 368                  * it in so_name.
 369                  */
 370                 if (off_pathname != 0) {
 371                         target_read_string(read_pointer(kld + off_pathname),
 372                             &path, sizeof(new->so_name), &error);
 373                         if (error != 0) {
 374                                 warning(
 375                     "kld_current_sos: Can't read pathname for \"%s\": %s\n",
 376                                     new->so_original_name,
 377                                     safe_strerror(error));
 378                                 strlcpy(new->so_name, new->so_original_name,
 379                                     sizeof(new->so_name));
 380                         } else {
 381                                 strlcpy(new->so_name, path,
 382                                     sizeof(new->so_name));
 383                                 xfree(path);
 384                         }
 385                 } else
 386                         strlcpy(new->so_name, new->so_original_name,
 387                             sizeof(new->so_name));
 388
 389                 /* Read this kld's base address. */
 390                 new->lm_info->base_address = read_pointer(kld + off_address);
 391                 if (new->lm_info->base_address == 0) {
 392                         warning(
 393                             "kld_current_sos: Invalid address for kld \"%s\"",
 394                             new->so_original_name);
 395                         free_so(new);
 396                         continue;
 397                 }
 398
 399                 /* Append to the list. */
 400                 *prev = new;
 401                 prev = &new->next;
 402         }
 403
 404         return (head);
 405 }
 406
 407 static int
 408 kld_open_symbol_file_object (void *from_ttyp)
 409 {
 410
 411         return (0);
 412 }
 413
 414 static int
 415 kld_in_dynsym_resolve_code (CORE_ADDR pc)
 416 {
 417
 418         return (0);
 419 }
 420
 421 static int
 422 kld_find_and_open_solib (char *solib, unsigned o_flags, char **temp_pathname)
 423 {
 424         char path[PATH_MAX];
 425         int fd;
 426
 427         *temp_pathname = NULL;
 428         if (!find_kld_path(solib, path, sizeof(path))) {
 429                 errno = ENOENT;
 430                 return (-1);
 431         }
 432         fd = open(path, o_flags, 0);
 433         if (fd >= 0)
 434                 *temp_pathname = xstrdup(path);
 435         return (fd);
 436 }
 437
 438 void
 439 kld_new_objfile (struct objfile *objfile)
 440 {
 441
 442         if (!have_partial_symbols())
 443                 return;
 444
 445         /*
 446          * Compute offsets of relevant members in struct linker_file
 447          * and the addresses of global variables.  Don't warn about
 448          * kernels that don't have 'pathname' in the linker_file
 449          * struct since 6.x kernels don't have it.
 450          */
 451         off_address = kgdb_parse("&((struct linker_file *)0)->address");
 452         off_filename = kgdb_parse("&((struct linker_file *)0)->filename");
 453         off_pathname = kgdb_parse_quiet("&((struct linker_file *)0)->pathname");
 454         off_next = kgdb_parse("&((struct linker_file *)0)->link.tqe_next");
 455         module_path_addr = kgdb_parse("linker_path");
 456         linker_files_addr = kgdb_parse("&linker_files.tqh_first");
 457         kernel_file_addr = kgdb_parse("&linker_kernel_file");
 458 }
 459
 460 static int
 461 load_klds_stub (void *arg)
 462 {
 463
 464         solib_add(NULL, 1, &current_target, auto_solib_add);
 465         return (0);
 466 }
 467
 468 void
 469 kld_init (void)
 470 {
 471         /* XXX hack, needs to go into an abi init function */
 472         set_solib_ops(get_current_arch(), &kld_so_ops);
 473
 474         kld_new_objfile(NULL);
 475         catch_errors(load_klds_stub, NULL, NULL, RETURN_MASK_ALL);
 476         observer_attach_new_objfile(kld_new_objfile);
 477 }
 478
 479 void
 480 initialize_kld_target(void)
 481 {
 482         struct cmd_list_element *c;
 483
 484         kld_so_ops.relocate_section_addresses = kld_relocate_section_addresses;
 485         kld_so_ops.free_so = kld_free_so;
 486         kld_so_ops.clear_solib = kld_clear_solib;
 487         kld_so_ops.solib_create_inferior_hook = kld_solib_create_inferior_hook;
 488         kld_so_ops.special_symbol_handling = kld_special_symbol_handling;
 489         kld_so_ops.current_sos = kld_current_sos;
 490         kld_so_ops.open_symbol_file_object = kld_open_symbol_file_object;
 491         kld_so_ops.in_dynsym_resolve_code = kld_in_dynsym_resolve_code;
 492         kld_so_ops.find_and_open_solib = kld_find_and_open_solib;
 493         kld_so_ops.bfd_open = solib_bfd_open;
 494
 495         c = add_com("add-kld", class_files, kgdb_add_kld_cmd,
 496            "Usage: add-kld FILE\n\
 497 Load the symbols from the kernel loadable module FILE.");
 498         set_cmd_completer(c, filename_completer);
 499 }