1 /* Interfaces for libdwfl. 2 Copyright (C) 2005-2010, 2013 Red Hat, Inc. 3 This file is part of elfutils. 4 5 This file is free software; you can redistribute it and/or modify 6 it under the terms of either 7 8 * the GNU Lesser General Public License as published by the Free 9 Software Foundation; either version 3 of the License, or (at 10 your option) any later version 11 12 or 13 14 * the GNU General Public License as published by the Free 15 Software Foundation; either version 2 of the License, or (at 16 your option) any later version 17 18 or both in parallel, as here. 19 20 elfutils is distributed in the hope that it will be useful, but 21 WITHOUT ANY WARRANTY; without even the implied warranty of 22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 23 General Public License for more details. 24 25 You should have received copies of the GNU General Public License and 26 the GNU Lesser General Public License along with this program. If 27 not, see <http://www.gnu.org/licenses/>. */ 28 29 #ifndef _LIBDWFL_H 30 #define _LIBDWFL_H 1 31 32 #include "libdw.h" 33 #include <stdio.h> 34 35 /* Handle for a session using the library. */ 36 typedef struct Dwfl Dwfl; 37 38 /* Handle for a module. */ 39 typedef struct Dwfl_Module Dwfl_Module; 40 41 /* Handle describing a line record. */ 42 typedef struct Dwfl_Line Dwfl_Line; 43 44 /* This holds information common for all the frames of one backtrace for 45 a partical thread/task/TID. Several threads belong to one Dwfl. */ 46 typedef struct Dwfl_Thread Dwfl_Thread; 47 48 /* This holds everything we know about the state of the frame at a particular 49 PC location described by an FDE belonging to Dwfl_Thread. */ 50 typedef struct Dwfl_Frame Dwfl_Frame; 51 52 /* Callbacks. */ 53 typedef struct 54 { 55 int (*find_elf) (Dwfl_Module *mod, void **userdata, 56 const char *modname, Dwarf_Addr base, 57 char **file_name, Elf **elfp); 58 59 int (*find_debuginfo) (Dwfl_Module *mod, void **userdata, 60 const char *modname, Dwarf_Addr base, 61 const char *file_name, 62 const char *debuglink_file, GElf_Word debuglink_crc, 63 char **debuginfo_file_name); 64 65 /* Fill *ADDR with the loaded address of the section called SECNAME in 66 the given module. Use (Dwarf_Addr) -1 if this section is omitted from 67 accessible memory. This is called exactly once for each SHF_ALLOC 68 section that relocations affecting DWARF data refer to, so it can 69 easily be used to collect state about the sections referenced. */ 70 int (*section_address) (Dwfl_Module *mod, void **userdata, 71 const char *modname, Dwarf_Addr base, 72 const char *secname, 73 GElf_Word shndx, const GElf_Shdr *shdr, 74 Dwarf_Addr *addr); 75 76 char **debuginfo_path; /* See dwfl_standard_find_debuginfo. */ 77 } Dwfl_Callbacks; 78 79 80 #ifdef __cplusplus 81 extern "C" { 82 #endif 83 84 /* Start a new session with the library. */ 85 extern Dwfl *dwfl_begin (const Dwfl_Callbacks *callbacks) 86 __nonnull_attribute__ (1); 87 88 89 /* End a session. */ 90 extern void dwfl_end (Dwfl *); 91 92 /* Return implementation's version string suitable for printing. */ 93 extern const char *dwfl_version (Dwfl *); 94 95 /* Return error code of last failing function call. This value is kept 96 separately for each thread. */ 97 extern int dwfl_errno (void); 98 99 /* Return error string for ERROR. If ERROR is zero, return error string 100 for most recent error or NULL if none occurred. If ERROR is -1 the 101 behaviour is similar to the last case except that not NULL but a legal 102 string is returned. */ 103 extern const char *dwfl_errmsg (int err); 104 105 106 /* Start reporting the current set of segments and modules to the library. 107 All existing segments are wiped. Existing modules are marked to be 108 deleted, and will not be found via dwfl_addrmodule et al if they are not 109 re-reported before dwfl_report_end is called. */ 110 extern void dwfl_report_begin (Dwfl *dwfl); 111 112 /* Report that segment NDX begins at PHDR->p_vaddr + BIAS. 113 If NDX is < 0, the value succeeding the last call's NDX 114 is used instead (zero on the first call). 115 116 If nonzero, the smallest PHDR->p_align value seen sets the 117 effective page size for the address space DWFL describes. 118 This is the granularity at which reported module boundary 119 addresses will be considered to fall in or out of a segment. 120 121 Returns -1 for errors, or NDX (or its assigned replacement) on success. 122 123 When NDX is the value succeeding the last call's NDX (or is implicitly 124 so as above), IDENT is nonnull and matches the value in the last call, 125 and the PHDR and BIAS values reflect a segment that would be contiguous, 126 in both memory and file, with the last segment reported, then this 127 segment may be coalesced internally with preceding segments. When given 128 an address inside this segment, dwfl_addrsegment may return the NDX of a 129 preceding contiguous segment. To prevent coalesced segments, always 130 pass a null pointer for IDENT. 131 132 The values passed are not stored (except to track coalescence). 133 The only information that can be extracted from DWFL later is the 134 mapping of an address to a segment index that starts at or below 135 it. Reporting segments at all is optional. Its only benefit to 136 the caller is to offer this quick lookup via dwfl_addrsegment, 137 or use other segment-based calls. */ 138 extern int dwfl_report_segment (Dwfl *dwfl, int ndx, 139 const GElf_Phdr *phdr, GElf_Addr bias, 140 const void *ident); 141 142 /* Report that a module called NAME spans addresses [START, END). 143 Returns the module handle, either existing or newly allocated, 144 or returns a null pointer for an allocation error. */ 145 extern Dwfl_Module *dwfl_report_module (Dwfl *dwfl, const char *name, 146 Dwarf_Addr start, Dwarf_Addr end); 147 148 /* Report a module to address BASE with start and end addresses computed 149 from the ELF program headers in the given file - see the table below. 150 FD may be -1 to open FILE_NAME. On success, FD is consumed by the 151 library, and the `find_elf' callback will not be used for this module. 152 ADD_P_VADDR BASE 153 ET_EXEC ignored ignored 154 ET_DYN false absolute address where to place the file 155 true start address relative to ELF's phdr p_vaddr 156 ET_REL ignored absolute address where to place the file 157 ET_CORE ignored ignored 158 ET_DYN ELF phdr p_vaddr address can be non-zero if the shared library 159 has been prelinked by tool prelink(8). */ 160 extern Dwfl_Module *dwfl_report_elf (Dwfl *dwfl, const char *name, 161 const char *file_name, int fd, 162 GElf_Addr base, bool add_p_vaddr); 163 164 /* Similar, but report the module for offline use. All ET_EXEC files 165 being reported must be reported before any relocatable objects. 166 If this is used, dwfl_report_module and dwfl_report_elf may not be 167 used in the same reporting session. */ 168 extern Dwfl_Module *dwfl_report_offline (Dwfl *dwfl, const char *name, 169 const char *file_name, int fd); 170 171 172 /* Finish reporting the current set of modules to the library. 173 If REMOVED is not null, it's called for each module that 174 existed before but was not included in the current report. 175 Returns a nonzero return value from the callback. 176 The callback may call dwfl_report_module; doing so with the 177 details of the module being removed prevents its removal. 178 DWFL cannot be used until this function has returned zero. */ 179 extern int dwfl_report_end (Dwfl *dwfl, 180 int (*removed) (Dwfl_Module *, void *, 181 const char *, Dwarf_Addr, 182 void *arg), 183 void *arg); 184 185 /* Start reporting additional modules to the library. No calls but 186 dwfl_report_* can be made on DWFL until dwfl_report_end is called. 187 This is like dwfl_report_begin, but all the old modules are kept on. 188 More dwfl_report_* calls can follow to add more modules. 189 When dwfl_report_end is called, no old modules will be removed. */ 190 extern void dwfl_report_begin_add (Dwfl *dwfl); 191 192 193 /* Return the name of the module, and for each non-null argument store 194 interesting details: *USERDATA is a location for storing your own 195 pointer, **USERDATA is initially null; *START and *END give the address 196 range covered by the module; *DWBIAS is the address bias for debugging 197 information, and *SYMBIAS for symbol table entries (either is -1 if not 198 yet accessed); *MAINFILE is the name of the ELF file, and *DEBUGFILE the 199 name of the debuginfo file (might be equal to *MAINFILE; either is null 200 if not yet accessed). */ 201 extern const char *dwfl_module_info (Dwfl_Module *mod, void ***userdata, 202 Dwarf_Addr *start, Dwarf_Addr *end, 203 Dwarf_Addr *dwbias, Dwarf_Addr *symbias, 204 const char **mainfile, 205 const char **debugfile); 206 207 /* Iterate through the modules, starting the walk with OFFSET == 0. 208 Calls *CALLBACK for each module as long as it returns DWARF_CB_OK. 209 When *CALLBACK returns another value, the walk stops and the 210 return value can be passed as OFFSET to resume it. Returns 0 when 211 there are no more modules, or -1 for errors. */ 212 extern ptrdiff_t dwfl_getmodules (Dwfl *dwfl, 213 int (*callback) (Dwfl_Module *, void **, 214 const char *, Dwarf_Addr, 215 void *arg), 216 void *arg, 217 ptrdiff_t offset); 218 219 /* Find the module containing the given address. */ 220 extern Dwfl_Module *dwfl_addrmodule (Dwfl *dwfl, Dwarf_Addr address); 221 222 /* Find the segment, if any, and module, if any, containing ADDRESS. 223 Returns a segment index returned by dwfl_report_segment, or -1 224 if no segment matches the address. Regardless of the return value, 225 *MOD is always set to the module containing ADDRESS, or to null. */ 226 extern int dwfl_addrsegment (Dwfl *dwfl, Dwarf_Addr address, Dwfl_Module **mod); 227 228 229 230 /* Report the known build ID bits associated with a module. 231 If VADDR is nonzero, it gives the absolute address where those 232 bits are found within the module. This can be called at any 233 time, but is usually used immediately after dwfl_report_module. 234 Once the module's main ELF file is opened, the ID note found 235 there takes precedence and cannot be changed. */ 236 extern int dwfl_module_report_build_id (Dwfl_Module *mod, 237 const unsigned char *bits, size_t len, 238 GElf_Addr vaddr) 239 __nonnull_attribute__ (2); 240 241 /* Extract the build ID bits associated with a module. 242 Returns -1 for errors, 0 if no ID is known, or the number of ID bytes. 243 When an ID is found, *BITS points to it; *VADDR is the absolute address 244 at which the ID bits are found within the module, or 0 if unknown. 245 246 This returns 0 when the module's main ELF file has not yet been loaded 247 and its build ID bits were not reported. To ensure the ID is always 248 returned when determinable, call dwfl_module_getelf first. */ 249 extern int dwfl_module_build_id (Dwfl_Module *mod, 250 const unsigned char **bits, GElf_Addr *vaddr) 251 __nonnull_attribute__ (2, 3); 252 253 254 /*** Standard callbacks ***/ 255 256 /* These standard find_elf and find_debuginfo callbacks are 257 controlled by a string specifying directories to look in. 258 If `debuginfo_path' is set in the Dwfl_Callbacks structure 259 and the char * it points to is not null, that supplies the 260 string. Otherwise a default path is used. 261 262 If the first character of the string is + or - that enables or 263 disables CRC32 checksum validation when it's necessary. The 264 remainder of the string is composed of elements separated by 265 colons. Each element can start with + or - to override the 266 global checksum behavior. This flag is never relevant when 267 working with build IDs, but it's always parsed in the path 268 string. The remainder of the element indicates a directory. 269 270 Searches by build ID consult only the elements naming absolute 271 directory paths. They look under those directories for a link 272 named ".build-id/xx/yy" or ".build-id/xx/yy.debug", where "xxyy" 273 is the lower-case hexadecimal representation of the ID bytes. 274 275 In searches for debuginfo by name, if the remainder of the 276 element is empty, the directory containing the main file is 277 tried; if it's an absolute path name, the absolute directory path 278 containing the main file is taken as a subdirectory of this path; 279 a relative path name is taken as a subdirectory of the directory 280 containing the main file. Hence for /bin/ls, the default string 281 ":.debug:/usr/lib/debug" says to look in /bin, then /bin/.debug, 282 then /usr/lib/debug/bin, for the file name in the .gnu_debuglink 283 section (or "ls.debug" if none was found). */ 284 285 /* Standard find_elf callback function working solely on build ID. 286 This can be tried first by any find_elf callback, to use the 287 bits passed to dwfl_module_report_build_id, if any. */ 288 extern int dwfl_build_id_find_elf (Dwfl_Module *, void **, 289 const char *, Dwarf_Addr, 290 char **, Elf **); 291 292 /* Standard find_debuginfo callback function working solely on build ID. 293 This can be tried first by any find_debuginfo callback, 294 to use the build ID bits from the main file when present. */ 295 extern int dwfl_build_id_find_debuginfo (Dwfl_Module *, void **, 296 const char *, Dwarf_Addr, 297 const char *, const char *, 298 GElf_Word, char **); 299 300 /* Standard find_debuginfo callback function. 301 If a build ID is available, this tries first to use that. 302 If there is no build ID or no valid debuginfo found by ID, 303 it searches the debuginfo path by name, as described above. 304 Any file found in the path is validated by build ID if possible, 305 or else by CRC32 checksum if enabled, and skipped if it does not match. */ 306 extern int dwfl_standard_find_debuginfo (Dwfl_Module *, void **, 307 const char *, Dwarf_Addr, 308 const char *, const char *, 309 GElf_Word, char **); 310 311 312 /* This callback must be used when using dwfl_offline_* to report modules, 313 if ET_REL is to be supported. */ 314 extern int dwfl_offline_section_address (Dwfl_Module *, void **, 315 const char *, Dwarf_Addr, 316 const char *, GElf_Word, 317 const GElf_Shdr *, 318 Dwarf_Addr *addr); 319 320 321 /* Callbacks for working with kernel modules in the running Linux kernel. */ 322 extern int dwfl_linux_kernel_find_elf (Dwfl_Module *, void **, 323 const char *, Dwarf_Addr, 324 char **, Elf **); 325 extern int dwfl_linux_kernel_module_section_address (Dwfl_Module *, void **, 326 const char *, Dwarf_Addr, 327 const char *, GElf_Word, 328 const GElf_Shdr *, 329 Dwarf_Addr *addr); 330 331 /* Call dwfl_report_elf for the running Linux kernel. 332 Returns zero on success, -1 if dwfl_report_module failed, 333 or an errno code if opening the kernel binary failed. */ 334 extern int dwfl_linux_kernel_report_kernel (Dwfl *dwfl); 335 336 /* Call dwfl_report_module for each kernel module in the running Linux kernel. 337 Returns zero on success, -1 if dwfl_report_module failed, 338 or an errno code if reading the list of modules failed. */ 339 extern int dwfl_linux_kernel_report_modules (Dwfl *dwfl); 340 341 /* Report a kernel and its modules found on disk, for offline use. 342 If RELEASE starts with '/', it names a directory to look in; 343 if not, it names a directory to find under /lib/modules/; 344 if null, /lib/modules/`uname -r` is used. 345 Returns zero on success, -1 if dwfl_report_module failed, 346 or an errno code if finding the files on disk failed. 347 348 If PREDICATE is not null, it is called with each module to be reported; 349 its arguments are the module name, and the ELF file name or null if unknown, 350 and its return value should be zero to skip the module, one to report it, 351 or -1 to cause the call to fail and return errno. */ 352 extern int dwfl_linux_kernel_report_offline (Dwfl *dwfl, const char *release, 353 int (*predicate) (const char *, 354 const char *)); 355 356 /* Examine an ET_CORE file and report modules based on its contents. 357 This can follow a dwfl_report_offline call to bootstrap the 358 DT_DEBUG method of following the dynamic linker link_map chain, in 359 case the core file does not contain enough of the executable's text 360 segment to locate its PT_DYNAMIC in the dump. In such case you need to 361 supply non-NULL EXECUTABLE, otherwise dynamic libraries will not be loaded 362 into the DWFL map. This might call dwfl_report_elf on file names found in 363 the dump if reading some link_map files is the only way to ascertain those 364 modules' addresses. Returns the number of modules reported, or -1 for 365 errors. */ 366 extern int dwfl_core_file_report (Dwfl *dwfl, Elf *elf, const char *executable); 367 368 /* Call dwfl_report_module for each file mapped into the address space of PID. 369 Returns zero on success, -1 if dwfl_report_module failed, 370 or an errno code if opening the proc files failed. */ 371 extern int dwfl_linux_proc_report (Dwfl *dwfl, pid_t pid); 372 373 /* Similar, but reads an input stream in the format of Linux /proc/PID/maps 374 files giving module layout, not the file for a live process. */ 375 extern int dwfl_linux_proc_maps_report (Dwfl *dwfl, FILE *); 376 377 /* Trivial find_elf callback for use with dwfl_linux_proc_report. 378 This uses the module name as a file name directly and tries to open it 379 if it begin with a slash, or handles the magic string "[vdso]". */ 380 extern int dwfl_linux_proc_find_elf (Dwfl_Module *mod, void **userdata, 381 const char *module_name, Dwarf_Addr base, 382 char **file_name, Elf **); 383 384 /* Standard argument parsing for using a standard callback set. */ 385 struct argp; 386 extern const struct argp *dwfl_standard_argp (void) __attribute__ ((const)); 387 388 389 /*** Relocation of addresses from Dwfl ***/ 390 391 /* Return the number of relocatable bases associated with the module, 392 which is zero for ET_EXEC and one for ET_DYN. Returns -1 for errors. */ 393 extern int dwfl_module_relocations (Dwfl_Module *mod); 394 395 /* Return the relocation base index associated with the *ADDRESS location, 396 and adjust *ADDRESS to be an offset relative to that base. 397 Returns -1 for errors. */ 398 extern int dwfl_module_relocate_address (Dwfl_Module *mod, 399 Dwarf_Addr *address); 400 401 /* Return the ELF section name for the given relocation base index; 402 if SHNDXP is not null, set *SHNDXP to the ELF section index. 403 For ET_DYN, returns "" and sets *SHNDXP to SHN_ABS; the relocation 404 base is the runtime start address reported for the module. 405 Returns null for errors. */ 406 extern const char *dwfl_module_relocation_info (Dwfl_Module *mod, 407 unsigned int idx, 408 GElf_Word *shndxp); 409 410 /* Validate that ADDRESS and ADDRESS+OFFSET lie in a known module 411 and both within the same contiguous region for relocation purposes. 412 Returns zero for success and -1 for errors. */ 413 extern int dwfl_validate_address (Dwfl *dwfl, 414 Dwarf_Addr address, Dwarf_Sword offset); 415 416 417 /*** ELF access functions ***/ 418 419 /* Fetch the module main ELF file (where the allocated sections 420 are found) for use with libelf. If successful, fills in *BIAS 421 with the difference between addresses within the loaded module 422 and those in symbol tables or Dwarf information referring to it. */ 423 extern Elf *dwfl_module_getelf (Dwfl_Module *, GElf_Addr *bias) 424 __nonnull_attribute__ (1, 2); 425 426 /* Return the number of symbols in the module's symbol table, 427 or -1 for errors. */ 428 extern int dwfl_module_getsymtab (Dwfl_Module *mod); 429 430 /* Return the index of the first global symbol in the module's symbol 431 table, or -1 for errors. In each symbol table, all symbols with 432 STB_LOCAL binding precede the weak and global symbols. This 433 function returns the symbol table index one greater than the last 434 local symbol. */ 435 extern int dwfl_module_getsymtab_first_global (Dwfl_Module *mod); 436 437 /* Fetch one entry from the module's symbol table. On errors, returns 438 NULL. If successful, fills in *SYM and returns the string for st_name. 439 This works like gelf_getsym except that st_value is always adjusted to 440 an absolute value based on the module's location, when the symbol is in 441 an SHF_ALLOC section. If SHNDXP is non-null, it's set with the section 442 index (whether from st_shndx or extended index table); in case of a 443 symbol in a non-allocated section, *SHNDXP is instead set to -1. 444 Note that since symbols can come from either the main, debug or auxiliary 445 ELF symbol file (either dynsym or symtab) the section index can only 446 be reliably used to compare against special section constants like 447 SHN_UNDEF or SHN_ABS. It is recommended to use dwfl_module_getsym_info 448 which doesn't have these deficiencies. */ 449 extern const char *dwfl_module_getsym (Dwfl_Module *mod, int ndx, 450 GElf_Sym *sym, GElf_Word *shndxp) 451 __nonnull_attribute__ (3); 452 453 /* Fetch one entry from the module's symbol table and the associated 454 address value. On errors, returns NULL. If successful, fills in 455 *SYM, *ADDR and returns the string for st_name. This works like 456 gelf_getsym. *ADDR is set to the st_value adjusted to an absolute 457 value based on the module's location, when the symbol is in an 458 SHF_ALLOC section. For non-ET_REL files, if the arch uses function 459 descriptors, and the st_value points to one, *ADDR will be resolved 460 to the actual function entry address. The SYM->ST_VALUE itself 461 isn't adjusted in any way. Fills in ELFP, if not NULL, with the 462 ELF file the symbol originally came from. Note that symbols can 463 come from either the main, debug or auxiliary ELF symbol file 464 (either dynsym or symtab). If SHNDXP is non-null, it's set with 465 the section index (whether from st_shndx or extended index table); 466 in case of a symbol in a non-allocated section, *SHNDXP is instead 467 set to -1. Fills in BIAS, if not NULL, with the difference between 468 addresses within the loaded module and those in symbol table of the 469 ELF file. Note that the address associated with the symbol might 470 be in a different section than the returned symbol. The section in 471 the main elf file in which returned ADDR falls can be found with 472 dwfl_module_address_section. */ 473 extern const char *dwfl_module_getsym_info (Dwfl_Module *mod, int ndx, 474 GElf_Sym *sym, GElf_Addr *addr, 475 GElf_Word *shndxp, 476 Elf **elfp, Dwarf_Addr *bias) 477 __nonnull_attribute__ (3, 4); 478 479 /* Find the symbol that ADDRESS lies inside, and return its name. */ 480 extern const char *dwfl_module_addrname (Dwfl_Module *mod, GElf_Addr address); 481 482 /* Find the symbol associated with ADDRESS. Return its name or NULL 483 when nothing was found. If the architecture uses function 484 descriptors, and symbol st_value points to one, ADDRESS wil be 485 matched against either the adjusted st_value or the associated 486 function entry value as described in dwfl_module_getsym_info. If 487 OFFSET is not NULL it will be filled in with the difference from 488 the start of the symbol (or function entry). If SYM is not NULL it 489 is filled in with the symbol associated with the matched ADDRESS. 490 The SYM->ST_VALUE itself isn't adjusted in any way. Fills in ELFP, 491 if not NULL, with the ELF file the symbol originally came from. 492 Note that symbols can come from either the main, debug or auxiliary 493 ELF symbol file (either dynsym or symtab). If SHNDXP is non-null, 494 it's set with the section index (whether from st_shndx or extended 495 index table). Fills in BIAS, if not NULL, with the difference 496 between addresses within the loaded module and those in symbol 497 table of the ELF file. Note that the address matched against the 498 symbol might be in a different section than the returned symbol. 499 The section in the main elf file in ADDRESS falls can be found with 500 dwfl_module_address_section. */ 501 extern const char *dwfl_module_addrinfo (Dwfl_Module *mod, GElf_Addr address, 502 GElf_Off *offset, GElf_Sym *sym, 503 GElf_Word *shndxp, Elf **elfp, 504 Dwarf_Addr *bias) 505 __nonnull_attribute__ (3); 506 507 /* Find the symbol that ADDRESS lies inside, and return detailed 508 information as for dwfl_module_getsym (above). Note that like 509 dwfl_module_getsym this function also adjusts SYM->ST_VALUE to an 510 absolute value based on the module's location. ADDRESS is only 511 matched against this adjusted SYM->ST_VALUE. This means that 512 depending on architecture this might only match symbols that 513 represent function descriptor addresses (and not function entry 514 addresses). For these reasons it is recommended to use 515 dwfl_module_addrinfo instead. */ 516 extern const char *dwfl_module_addrsym (Dwfl_Module *mod, GElf_Addr address, 517 GElf_Sym *sym, GElf_Word *shndxp) 518 __nonnull_attribute__ (3); 519 520 /* Find the ELF section that *ADDRESS lies inside and return it. 521 On success, adjusts *ADDRESS to be relative to the section, 522 and sets *BIAS to the difference between addresses used in 523 the returned section's headers and run-time addresses. */ 524 extern Elf_Scn *dwfl_module_address_section (Dwfl_Module *mod, 525 Dwarf_Addr *address, 526 Dwarf_Addr *bias) 527 __nonnull_attribute__ (2, 3); 528 529 530 /*** Dwarf access functions ***/ 531 532 /* Fetch the module's debug information for use with libdw. 533 If successful, fills in *BIAS with the difference between 534 addresses within the loaded module and those to use with libdw. */ 535 extern Dwarf *dwfl_module_getdwarf (Dwfl_Module *, Dwarf_Addr *bias) 536 __nonnull_attribute__ (2); 537 538 /* Get the libdw handle for each module. */ 539 extern ptrdiff_t dwfl_getdwarf (Dwfl *, 540 int (*callback) (Dwfl_Module *, void **, 541 const char *, Dwarf_Addr, 542 Dwarf *, Dwarf_Addr, void *), 543 void *arg, ptrdiff_t offset); 544 545 /* Look up the module containing ADDR and return its debugging information, 546 loading it if necessary. */ 547 extern Dwarf *dwfl_addrdwarf (Dwfl *dwfl, Dwarf_Addr addr, Dwarf_Addr *bias) 548 __nonnull_attribute__ (3); 549 550 551 /* Find the CU containing ADDR and return its DIE. */ 552 extern Dwarf_Die *dwfl_addrdie (Dwfl *dwfl, Dwarf_Addr addr, Dwarf_Addr *bias) 553 __nonnull_attribute__ (3); 554 extern Dwarf_Die *dwfl_module_addrdie (Dwfl_Module *mod, 555 Dwarf_Addr addr, Dwarf_Addr *bias) 556 __nonnull_attribute__ (3); 557 558 /* Iterate through the CUs, start with null for LASTCU. */ 559 extern Dwarf_Die *dwfl_nextcu (Dwfl *dwfl, Dwarf_Die *lastcu, Dwarf_Addr *bias) 560 __nonnull_attribute__ (3); 561 extern Dwarf_Die *dwfl_module_nextcu (Dwfl_Module *mod, 562 Dwarf_Die *lastcu, Dwarf_Addr *bias) 563 __nonnull_attribute__ (3); 564 565 /* Return the module containing the CU DIE. */ 566 extern Dwfl_Module *dwfl_cumodule (Dwarf_Die *cudie); 567 568 569 /* Cache the source line information fo the CU and return the 570 number of Dwfl_Line entries it has. */ 571 extern int dwfl_getsrclines (Dwarf_Die *cudie, size_t *nlines); 572 573 /* Access one line number entry within the CU. */ 574 extern Dwfl_Line *dwfl_onesrcline (Dwarf_Die *cudie, size_t idx); 575 576 /* Get source for address. */ 577 extern Dwfl_Line *dwfl_module_getsrc (Dwfl_Module *mod, Dwarf_Addr addr); 578 extern Dwfl_Line *dwfl_getsrc (Dwfl *dwfl, Dwarf_Addr addr); 579 580 /* Get address for source. */ 581 extern int dwfl_module_getsrc_file (Dwfl_Module *mod, 582 const char *fname, int lineno, int column, 583 Dwfl_Line ***srcsp, size_t *nsrcs); 584 585 /* Return the module containing this line record. */ 586 extern Dwfl_Module *dwfl_linemodule (Dwfl_Line *line); 587 588 /* Return the CU containing this line record. */ 589 extern Dwarf_Die *dwfl_linecu (Dwfl_Line *line); 590 591 /* Return the source file name and fill in other information. 592 Arguments may be null for unneeded fields. */ 593 extern const char *dwfl_lineinfo (Dwfl_Line *line, Dwarf_Addr *addr, 594 int *linep, int *colp, 595 Dwarf_Word *mtime, Dwarf_Word *length); 596 597 /* Return the equivalent Dwarf_Line and the bias to apply to its address. */ 598 extern Dwarf_Line *dwfl_dwarf_line (Dwfl_Line *line, Dwarf_Addr *bias); 599 600 /* Return the compilation directory (AT_comp_dir) from this line's CU. */ 601 extern const char *dwfl_line_comp_dir (Dwfl_Line *line); 602 603 604 /*** Machine backend access functions ***/ 605 606 /* Return location expression to find return value given a 607 DW_TAG_subprogram, DW_TAG_subroutine_type, or similar DIE describing 608 function itself (whose DW_AT_type attribute describes its return type). 609 The given DIE must come from the given module. Returns -1 for errors. 610 Returns zero if the function has no return value (e.g. "void" in C). 611 Otherwise, *LOCOPS gets a location expression to find the return value, 612 and returns the number of operations in the expression. The pointer is 613 permanently allocated at least as long as the module is live. */ 614 extern int dwfl_module_return_value_location (Dwfl_Module *mod, 615 Dwarf_Die *functypedie, 616 const Dwarf_Op **locops); 617 618 /* Enumerate the DWARF register numbers and their names. 619 For each register, CALLBACK gets its DWARF number, a string describing 620 the register set (such as "integer" or "FPU"), a prefix used in 621 assembler syntax (such as "%" or "$", may be ""), and the name for the 622 register (contains identifier characters only, possibly all digits). 623 The REGNAME string is valid only during the callback. */ 624 extern int dwfl_module_register_names (Dwfl_Module *mod, 625 int (*callback) (void *arg, 626 int regno, 627 const char *setname, 628 const char *prefix, 629 const char *regname, 630 int bits, int type), 631 void *arg); 632 633 634 /* Find the CFI for this module. Returns NULL if there is no CFI. 635 On success, fills in *BIAS with the difference between addresses 636 within the loaded module and those in the CFI referring to it. 637 The pointer returned can be used until the module is cleaned up. 638 Calling these more than once returns the same pointers. 639 640 dwfl_module_dwarf_cfi gets the '.debug_frame' information found with the 641 rest of the DWARF information. dwfl_module_eh_cfi gets the '.eh_frame' 642 information found linked into the text. A module might have either or 643 both. */ 644 extern Dwarf_CFI *dwfl_module_dwarf_cfi (Dwfl_Module *mod, Dwarf_Addr *bias); 645 extern Dwarf_CFI *dwfl_module_eh_cfi (Dwfl_Module *mod, Dwarf_Addr *bias); 646 647 648 typedef struct 649 { 650 /* Called to iterate through threads. Returns next TID (thread ID) on 651 success, a negative number on failure and zero if there are no more 652 threads. dwfl_errno () should be set if negative number has been 653 returned. *THREAD_ARGP is NULL on first call, and may be optionally 654 set by the implementation. The value set by the implementation will 655 be passed in on the next call to NEXT_THREAD. THREAD_ARGP is never 656 NULL. *THREAD_ARGP will be passed to set_initial_registers or 657 thread_detach callbacks together with Dwfl_Thread *thread. This 658 method must not be NULL. */ 659 pid_t (*next_thread) (Dwfl *dwfl, void *dwfl_arg, void **thread_argp) 660 __nonnull_attribute__ (1); 661 662 /* Called to get a specific thread. Returns true if there is a 663 thread with the given thread id number, returns false if no such 664 thread exists and will set dwfl_errno in that case. THREAD_ARGP 665 is never NULL. *THREAD_ARGP will be passed to 666 set_initial_registers or thread_detach callbacks together with 667 Dwfl_Thread *thread. This method may be NULL and will then be 668 emulated using the next_thread callback. */ 669 bool (*get_thread) (Dwfl *dwfl, pid_t tid, void *dwfl_arg, 670 void **thread_argp) 671 __nonnull_attribute__ (1); 672 673 /* Called during unwinding to access memory (stack) state. Returns true for 674 successfully read *RESULT or false and sets dwfl_errno () on failure. 675 This method may be NULL - in such case dwfl_thread_getframes will return 676 only the initial frame. */ 677 bool (*memory_read) (Dwfl *dwfl, Dwarf_Addr addr, Dwarf_Word *result, 678 void *dwfl_arg) 679 __nonnull_attribute__ (1, 3); 680 681 /* Called on initial unwind to get the initial register state of the first 682 frame. Should call dwfl_thread_state_registers, possibly multiple times 683 for different ranges and possibly also dwfl_thread_state_register_pc, to 684 fill in initial (DWARF) register values. After this call, till at least 685 thread_detach is called, the thread is assumed to be frozen, so that it is 686 safe to unwind. Returns true on success or false and sets dwfl_errno () 687 on failure. In the case of a failure thread_detach will not be called. 688 This method must not be NULL. */ 689 bool (*set_initial_registers) (Dwfl_Thread *thread, void *thread_arg) 690 __nonnull_attribute__ (1); 691 692 /* Called by dwfl_end. All thread_detach method calls have been already 693 done. This method may be NULL. */ 694 void (*detach) (Dwfl *dwfl, void *dwfl_arg) 695 __nonnull_attribute__ (1); 696 697 /* Called when unwinding is done. No callback will be called after 698 this method has been called. Iff set_initial_registers was called for 699 a TID and it returned success thread_detach will be called before the 700 detach method above. This method may be NULL. */ 701 void (*thread_detach) (Dwfl_Thread *thread, void *thread_arg) 702 __nonnull_attribute__ (1); 703 } Dwfl_Thread_Callbacks; 704 705 /* PID is the process id associated with the DWFL state. Architecture of DWFL 706 modules is specified by ELF, ELF must remain valid during DWFL lifetime. 707 Use NULL ELF to detect architecture from DWFL, the function will then detect 708 it from arbitrary Dwfl_Module of DWFL. DWFL_ARG is the callback backend 709 state. DWFL_ARG will be provided to the callbacks. *THREAD_CALLBACKS 710 function pointers must remain valid during lifetime of DWFL. Function 711 returns true on success, false otherwise. */ 712 bool dwfl_attach_state (Dwfl *dwfl, Elf *elf, pid_t pid, 713 const Dwfl_Thread_Callbacks *thread_callbacks, 714 void *dwfl_arg) 715 __nonnull_attribute__ (1, 4); 716 717 /* Calls dwfl_attach_state with Dwfl_Thread_Callbacks setup for extracting 718 thread state from the ELF core file. Returns the pid number extracted 719 from the core file, or -1 for errors. */ 720 extern int dwfl_core_file_attach (Dwfl *dwfl, Elf *elf); 721 722 /* Calls dwfl_attach_state with Dwfl_Thread_Callbacks setup for extracting 723 thread state from the proc file system. Uses ptrace to attach and stop 724 the thread under inspection and detaches when thread_detach is called 725 and unwinding for the thread is done, unless ASSUME_PTRACE_STOPPED is 726 true. If ASSUME_PTRACE_STOPPED is true the caller should make sure that 727 the thread is ptrace attached and stopped before unwinding by calling 728 either dwfl_thread_getframes or dwfl_getthread_frames. Returns zero on 729 success, -1 if dwfl_attach_state failed, or an errno code if opening the 730 proc files failed. */ 731 extern int dwfl_linux_proc_attach (Dwfl *dwfl, pid_t pid, 732 bool assume_ptrace_stopped); 733 734 /* Return PID for the process associated with DWFL. Function returns -1 if 735 dwfl_attach_state was not called for DWFL. */ 736 pid_t dwfl_pid (Dwfl *dwfl) 737 __nonnull_attribute__ (1); 738 739 /* Return DWFL from which THREAD was created using dwfl_getthreads. */ 740 Dwfl *dwfl_thread_dwfl (Dwfl_Thread *thread) 741 __nonnull_attribute__ (1); 742 743 /* Return positive TID (thread ID) for THREAD. This function never fails. */ 744 pid_t dwfl_thread_tid (Dwfl_Thread *thread) 745 __nonnull_attribute__ (1); 746 747 /* Return thread for frame STATE. This function never fails. */ 748 Dwfl_Thread *dwfl_frame_thread (Dwfl_Frame *state) 749 __nonnull_attribute__ (1); 750 751 /* Called by Dwfl_Thread_Callbacks.set_initial_registers implementation. 752 For every known continuous block of registers <FIRSTREG..FIRSTREG+NREGS) 753 (inclusive..exclusive) set their content to REGS (array of NREGS items). 754 Function returns false if any of the registers has invalid number. */ 755 bool dwfl_thread_state_registers (Dwfl_Thread *thread, int firstreg, 756 unsigned nregs, const Dwarf_Word *regs) 757 __nonnull_attribute__ (1, 4); 758 759 /* Called by Dwfl_Thread_Callbacks.set_initial_registers implementation. 760 If PC is not contained among DWARF registers passed by 761 dwfl_thread_state_registers on the target architecture pass the PC value 762 here. */ 763 void dwfl_thread_state_register_pc (Dwfl_Thread *thread, Dwarf_Word pc) 764 __nonnull_attribute__ (1); 765 766 /* Iterate through the threads for a process. Returns zero if all threads have 767 been processed by the callback, returns -1 on error, or the value of the 768 callback when not DWARF_CB_OK. -1 returned on error will set dwfl_errno (). 769 Keeps calling the callback with the next thread while the callback returns 770 DWARF_CB_OK, till there are no more threads. */ 771 int dwfl_getthreads (Dwfl *dwfl, 772 int (*callback) (Dwfl_Thread *thread, void *arg), 773 void *arg) 774 __nonnull_attribute__ (1, 2); 775 776 /* Iterate through the frames for a thread. Returns zero if all frames 777 have been processed by the callback, returns -1 on error, or the value of 778 the callback when not DWARF_CB_OK. -1 returned on error will 779 set dwfl_errno (). Some systems return error instead of zero on end of the 780 backtrace, for cross-platform compatibility callers should consider error as 781 a zero. Keeps calling the callback with the next frame while the callback 782 returns DWARF_CB_OK, till there are no more frames. On start will call the 783 set_initial_registers callback and on return will call the detach_thread 784 callback of the Dwfl_Thread. */ 785 int dwfl_thread_getframes (Dwfl_Thread *thread, 786 int (*callback) (Dwfl_Frame *state, void *arg), 787 void *arg) 788 __nonnull_attribute__ (1, 2); 789 790 /* Like dwfl_thread_getframes, but specifying the thread by its unique 791 identifier number. Returns zero if all frames have been processed 792 by the callback, returns -1 on error (and when no thread with 793 the given thread id number exists), or the value of the callback 794 when not DWARF_CB_OK. -1 returned on error will set dwfl_errno (). */ 795 int dwfl_getthread_frames (Dwfl *dwfl, pid_t tid, 796 int (*callback) (Dwfl_Frame *thread, void *arg), 797 void *arg) 798 __nonnull_attribute__ (1, 3); 799 800 /* Return *PC (program counter) for thread-specific frame STATE. 801 Set *ISACTIVATION according to DWARF frame "activation" definition. 802 Typically you need to substract 1 from *PC if *ACTIVATION is false to safely 803 find function of the caller. ACTIVATION may be NULL. PC must not be NULL. 804 Function returns false if it failed to find *PC. */ 805 bool dwfl_frame_pc (Dwfl_Frame *state, Dwarf_Addr *pc, bool *isactivation) 806 __nonnull_attribute__ (1, 2); 807 808 #ifdef __cplusplus 809 } 810 #endif 811 812 #endif /* libdwfl.h */ 813
