1 /* Interfaces for libdwfl.
2 Copyright (C) 2005-2010, 2013 Red Hat, Inc.
3 This file is part of elfutils.
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
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
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
18 or both in parallel, as here.
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.
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/>. */
35 /* Handle for a session using the library. */
36 typedef struct Dwfl Dwfl;
38 /* Handle for a module. */
39 typedef struct Dwfl_Module Dwfl_Module;
41 /* Handle describing a line record. */
42 typedef struct Dwfl_Line Dwfl_Line;
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;
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;
55 int (*find_elf) (Dwfl_Module *mod, void **userdata,
56 const char *modname, Dwarf_Addr base,
57 char **file_name, Elf **elfp);
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);
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,
73 GElf_Word shndx, const GElf_Shdr *shdr,
76 char **debuginfo_path; /* See dwfl_standard_find_debuginfo. */
84 /* Start a new session with the library. */
85 extern Dwfl *dwfl_begin (const Dwfl_Callbacks *callbacks)
86 __nonnull_attribute__ (1);
90 extern void dwfl_end (Dwfl *);
92 /* Return implementation's version string suitable for printing. */
93 extern const char *dwfl_version (Dwfl *);
95 /* Return error code of last failing function call. This value is kept
96 separately for each thread. */
97 extern int dwfl_errno (void);
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);
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);
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).
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.
121 Returns -1 for errors, or NDX (or its assigned replacement) on success.
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.
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,
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);
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.
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);
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);
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,
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);
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);
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,
219 /* Find the module containing the given address. */
220 extern Dwfl_Module *dwfl_addrmodule (Dwfl *dwfl, Dwarf_Addr address);
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);
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,
239 __nonnull_attribute__ (2);
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.
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);
254 /*** Standard callbacks ***/
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.
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.
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.
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 (and any subdirectory of that path) containing the main file is
279 taken as a subdirectory of this path; a relative path name is taken
280 as a subdirectory of the directory containing the main file.
281 Hence for /usr/bin/ls, the default string ":.debug:/usr/lib/debug"
282 says to look in /usr/bin, then /usr/bin/.debug, then the path subdirs
283 under /usr/lib/debug, in the order /usr/lib/debug/usr/bin, then
284 /usr/lib/debug/bin, and finally /usr/lib/debug, for the file name in
285 the .gnu_debuglink section (or "ls.debug" if none was found). */
287 /* Standard find_elf callback function working solely on build ID.
288 This can be tried first by any find_elf callback, to use the
289 bits passed to dwfl_module_report_build_id, if any. */
290 extern int dwfl_build_id_find_elf (Dwfl_Module *, void **,
291 const char *, Dwarf_Addr,
294 /* Standard find_debuginfo callback function working solely on build ID.
295 This can be tried first by any find_debuginfo callback,
296 to use the build ID bits from the main file when present. */
297 extern int dwfl_build_id_find_debuginfo (Dwfl_Module *, void **,
298 const char *, Dwarf_Addr,
299 const char *, const char *,
302 /* Standard find_debuginfo callback function.
303 If a build ID is available, this tries first to use that.
304 If there is no build ID or no valid debuginfo found by ID,
305 it searches the debuginfo path by name, as described above.
306 Any file found in the path is validated by build ID if possible,
307 or else by CRC32 checksum if enabled, and skipped if it does not match. */
308 extern int dwfl_standard_find_debuginfo (Dwfl_Module *, void **,
309 const char *, Dwarf_Addr,
310 const char *, const char *,
314 /* This callback must be used when using dwfl_offline_* to report modules,
315 if ET_REL is to be supported. */
316 extern int dwfl_offline_section_address (Dwfl_Module *, void **,
317 const char *, Dwarf_Addr,
318 const char *, GElf_Word,
323 /* Callbacks for working with kernel modules in the running Linux kernel. */
324 extern int dwfl_linux_kernel_find_elf (Dwfl_Module *, void **,
325 const char *, Dwarf_Addr,
327 extern int dwfl_linux_kernel_module_section_address (Dwfl_Module *, void **,
328 const char *, Dwarf_Addr,
329 const char *, GElf_Word,
333 /* Call dwfl_report_elf for the running Linux kernel.
334 Returns zero on success, -1 if dwfl_report_module failed,
335 or an errno code if opening the kernel binary failed. */
336 extern int dwfl_linux_kernel_report_kernel (Dwfl *dwfl);
338 /* Call dwfl_report_module for each kernel module in the running Linux kernel.
339 Returns zero on success, -1 if dwfl_report_module failed,
340 or an errno code if reading the list of modules failed. */
341 extern int dwfl_linux_kernel_report_modules (Dwfl *dwfl);
343 /* Report a kernel and its modules found on disk, for offline use.
344 If RELEASE starts with '/', it names a directory to look in;
345 if not, it names a directory to find under /lib/modules/;
346 if null, /lib/modules/`uname -r` is used.
347 Returns zero on success, -1 if dwfl_report_module failed,
348 or an errno code if finding the files on disk failed.
350 If PREDICATE is not null, it is called with each module to be reported;
351 its arguments are the module name, and the ELF file name or null if unknown,
352 and its return value should be zero to skip the module, one to report it,
353 or -1 to cause the call to fail and return errno. */
354 extern int dwfl_linux_kernel_report_offline (Dwfl *dwfl, const char *release,
355 int (*predicate) (const char *,
358 /* Examine an ET_CORE file and report modules based on its contents.
359 This can follow a dwfl_report_offline call to bootstrap the
360 DT_DEBUG method of following the dynamic linker link_map chain, in
361 case the core file does not contain enough of the executable's text
362 segment to locate its PT_DYNAMIC in the dump. In such case you need to
363 supply non-NULL EXECUTABLE, otherwise dynamic libraries will not be loaded
364 into the DWFL map. This might call dwfl_report_elf on file names found in
365 the dump if reading some link_map files is the only way to ascertain those
366 modules' addresses. Returns the number of modules reported, or -1 for
368 extern int dwfl_core_file_report (Dwfl *dwfl, Elf *elf, const char *executable);
370 /* Call dwfl_report_module for each file mapped into the address space of PID.
371 Returns zero on success, -1 if dwfl_report_module failed,
372 or an errno code if opening the proc files failed. */
373 extern int dwfl_linux_proc_report (Dwfl *dwfl, pid_t pid);
375 /* Similar, but reads an input stream in the format of Linux /proc/PID/maps
376 files giving module layout, not the file for a live process. */
377 extern int dwfl_linux_proc_maps_report (Dwfl *dwfl, FILE *);
379 /* Trivial find_elf callback for use with dwfl_linux_proc_report.
380 This uses the module name as a file name directly and tries to open it
381 if it begin with a slash, or handles the magic string "[vdso]". */
382 extern int dwfl_linux_proc_find_elf (Dwfl_Module *mod, void **userdata,
383 const char *module_name, Dwarf_Addr base,
384 char **file_name, Elf **);
386 /* Standard argument parsing for using a standard callback set. */
388 extern const struct argp *dwfl_standard_argp (void) __attribute__ ((const));
391 /*** Relocation of addresses from Dwfl ***/
393 /* Return the number of relocatable bases associated with the module,
394 which is zero for ET_EXEC and one for ET_DYN. Returns -1 for errors. */
395 extern int dwfl_module_relocations (Dwfl_Module *mod);
397 /* Return the relocation base index associated with the *ADDRESS location,
398 and adjust *ADDRESS to be an offset relative to that base.
399 Returns -1 for errors. */
400 extern int dwfl_module_relocate_address (Dwfl_Module *mod,
401 Dwarf_Addr *address);
403 /* Return the ELF section name for the given relocation base index;
404 if SHNDXP is not null, set *SHNDXP to the ELF section index.
405 For ET_DYN, returns "" and sets *SHNDXP to SHN_ABS; the relocation
406 base is the runtime start address reported for the module.
407 Returns null for errors. */
408 extern const char *dwfl_module_relocation_info (Dwfl_Module *mod,
412 /* Validate that ADDRESS and ADDRESS+OFFSET lie in a known module
413 and both within the same contiguous region for relocation purposes.
414 Returns zero for success and -1 for errors. */
415 extern int dwfl_validate_address (Dwfl *dwfl,
416 Dwarf_Addr address, Dwarf_Sword offset);
419 /*** ELF access functions ***/
421 /* Fetch the module main ELF file (where the allocated sections
422 are found) for use with libelf. If successful, fills in *BIAS
423 with the difference between addresses within the loaded module
424 and those in symbol tables or Dwarf information referring to it. */
425 extern Elf *dwfl_module_getelf (Dwfl_Module *, GElf_Addr *bias)
426 __nonnull_attribute__ (2);
428 /* Return the number of symbols in the module's symbol table,
430 extern int dwfl_module_getsymtab (Dwfl_Module *mod);
432 /* Return the index of the first global symbol in the module's symbol
433 table, or -1 for errors. In each symbol table, all symbols with
434 STB_LOCAL binding precede the weak and global symbols. This
435 function returns the symbol table index one greater than the last
437 extern int dwfl_module_getsymtab_first_global (Dwfl_Module *mod);
439 /* Fetch one entry from the module's symbol table. On errors, returns
440 NULL. If successful, fills in *SYM and returns the string for st_name.
441 This works like gelf_getsym except that st_value is always adjusted to
442 an absolute value based on the module's location, when the symbol is in
443 an SHF_ALLOC section. If SHNDXP is non-null, it's set with the section
444 index (whether from st_shndx or extended index table); in case of a
445 symbol in a non-allocated section, *SHNDXP is instead set to -1.
446 Note that since symbols can come from either the main, debug or auxiliary
447 ELF symbol file (either dynsym or symtab) the section index can only
448 be reliably used to compare against special section constants like
449 SHN_UNDEF or SHN_ABS. It is recommended to use dwfl_module_getsym_info
450 which doesn't have these deficiencies. */
451 extern const char *dwfl_module_getsym (Dwfl_Module *mod, int ndx,
452 GElf_Sym *sym, GElf_Word *shndxp)
453 __nonnull_attribute__ (3);
455 /* Fetch one entry from the module's symbol table and the associated
456 address value. On errors, returns NULL. If successful, fills in
457 *SYM, *ADDR and returns the string for st_name. This works like
458 gelf_getsym. *ADDR is set to the st_value adjusted to an absolute
459 value based on the module's location, when the symbol is in an
460 SHF_ALLOC section. For non-ET_REL files, if the arch uses function
461 descriptors, and the st_value points to one, *ADDR will be resolved
462 to the actual function entry address. The SYM->ST_VALUE itself
463 isn't adjusted in any way. Fills in ELFP, if not NULL, with the
464 ELF file the symbol originally came from. Note that symbols can
465 come from either the main, debug or auxiliary ELF symbol file
466 (either dynsym or symtab). If SHNDXP is non-null, it's set with
467 the section index (whether from st_shndx or extended index table);
468 in case of a symbol in a non-allocated section, *SHNDXP is instead
469 set to -1. Fills in BIAS, if not NULL, with the difference between
470 addresses within the loaded module and those in symbol table of the
471 ELF file. Note that the address associated with the symbol might
472 be in a different section than the returned symbol. The section in
473 the main elf file in which returned ADDR falls can be found with
474 dwfl_module_address_section. */
475 extern const char *dwfl_module_getsym_info (Dwfl_Module *mod, int ndx,
476 GElf_Sym *sym, GElf_Addr *addr,
478 Elf **elfp, Dwarf_Addr *bias)
479 __nonnull_attribute__ (3, 4);
481 /* Find the symbol that ADDRESS lies inside, and return its name. */
482 extern const char *dwfl_module_addrname (Dwfl_Module *mod, GElf_Addr address);
484 /* Find the symbol associated with ADDRESS. Return its name or NULL
485 when nothing was found. If the architecture uses function
486 descriptors, and symbol st_value points to one, ADDRESS wil be
487 matched against either the adjusted st_value or the associated
488 function entry value as described in dwfl_module_getsym_info. If
489 OFFSET is not NULL it will be filled in with the difference from
490 the start of the symbol (or function entry). If SYM is not NULL it
491 is filled in with the symbol associated with the matched ADDRESS.
492 The SYM->ST_VALUE itself isn't adjusted in any way. Fills in ELFP,
493 if not NULL, with the ELF file the symbol originally came from.
494 Note that symbols can come from either the main, debug or auxiliary
495 ELF symbol file (either dynsym or symtab). If SHNDXP is non-null,
496 it's set with the section index (whether from st_shndx or extended
497 index table). Fills in BIAS, if not NULL, with the difference
498 between addresses within the loaded module and those in symbol
499 table of the ELF file. Note that the address matched against the
500 symbol might be in a different section than the returned symbol.
501 The section in the main elf file in ADDRESS falls can be found with
502 dwfl_module_address_section. */
503 extern const char *dwfl_module_addrinfo (Dwfl_Module *mod, GElf_Addr address,
504 GElf_Off *offset, GElf_Sym *sym,
505 GElf_Word *shndxp, Elf **elfp,
507 __nonnull_attribute__ (3);
509 /* Find the symbol that ADDRESS lies inside, and return detailed
510 information as for dwfl_module_getsym (above). Note that like
511 dwfl_module_getsym this function also adjusts SYM->ST_VALUE to an
512 absolute value based on the module's location. ADDRESS is only
513 matched against this adjusted SYM->ST_VALUE. This means that
514 depending on architecture this might only match symbols that
515 represent function descriptor addresses (and not function entry
516 addresses). For these reasons it is recommended to use
517 dwfl_module_addrinfo instead. */
518 extern const char *dwfl_module_addrsym (Dwfl_Module *mod, GElf_Addr address,
519 GElf_Sym *sym, GElf_Word *shndxp)
520 __nonnull_attribute__ (3);
522 /* Find the ELF section that *ADDRESS lies inside and return it.
523 On success, adjusts *ADDRESS to be relative to the section,
524 and sets *BIAS to the difference between addresses used in
525 the returned section's headers and run-time addresses. */
526 extern Elf_Scn *dwfl_module_address_section (Dwfl_Module *mod,
529 __nonnull_attribute__ (2, 3);
532 /*** Dwarf access functions ***/
534 /* Fetch the module's debug information for use with libdw.
535 If successful, fills in *BIAS with the difference between
536 addresses within the loaded module and those to use with libdw. */
537 extern Dwarf *dwfl_module_getdwarf (Dwfl_Module *, Dwarf_Addr *bias)
538 __nonnull_attribute__ (2);
540 /* Get the libdw handle for each module. */
541 extern ptrdiff_t dwfl_getdwarf (Dwfl *,
542 int (*callback) (Dwfl_Module *, void **,
543 const char *, Dwarf_Addr,
544 Dwarf *, Dwarf_Addr, void *),
545 void *arg, ptrdiff_t offset);
547 /* Look up the module containing ADDR and return its debugging information,
548 loading it if necessary. */
549 extern Dwarf *dwfl_addrdwarf (Dwfl *dwfl, Dwarf_Addr addr, Dwarf_Addr *bias)
550 __nonnull_attribute__ (3);
553 /* Find the CU containing ADDR and return its DIE. */
554 extern Dwarf_Die *dwfl_addrdie (Dwfl *dwfl, Dwarf_Addr addr, Dwarf_Addr *bias)
555 __nonnull_attribute__ (3);
556 extern Dwarf_Die *dwfl_module_addrdie (Dwfl_Module *mod,
557 Dwarf_Addr addr, Dwarf_Addr *bias)
558 __nonnull_attribute__ (3);
560 /* Iterate through the CUs, start with null for LASTCU. */
561 extern Dwarf_Die *dwfl_nextcu (Dwfl *dwfl, Dwarf_Die *lastcu, Dwarf_Addr *bias)
562 __nonnull_attribute__ (3);
563 extern Dwarf_Die *dwfl_module_nextcu (Dwfl_Module *mod,
564 Dwarf_Die *lastcu, Dwarf_Addr *bias)
565 __nonnull_attribute__ (3);
567 /* Return the module containing the CU DIE. */
568 extern Dwfl_Module *dwfl_cumodule (Dwarf_Die *cudie);
571 /* Cache the source line information fo the CU and return the
572 number of Dwfl_Line entries it has. */
573 extern int dwfl_getsrclines (Dwarf_Die *cudie, size_t *nlines);
575 /* Access one line number entry within the CU. */
576 extern Dwfl_Line *dwfl_onesrcline (Dwarf_Die *cudie, size_t idx);
578 /* Get source for address. */
579 extern Dwfl_Line *dwfl_module_getsrc (Dwfl_Module *mod, Dwarf_Addr addr);
580 extern Dwfl_Line *dwfl_getsrc (Dwfl *dwfl, Dwarf_Addr addr);
582 /* Get address for source. */
583 extern int dwfl_module_getsrc_file (Dwfl_Module *mod,
584 const char *fname, int lineno, int column,
585 Dwfl_Line ***srcsp, size_t *nsrcs);
587 /* Return the module containing this line record. */
588 extern Dwfl_Module *dwfl_linemodule (Dwfl_Line *line);
590 /* Return the CU containing this line record. */
591 extern Dwarf_Die *dwfl_linecu (Dwfl_Line *line);
593 /* Return the source file name and fill in other information.
594 Arguments may be null for unneeded fields. */
595 extern const char *dwfl_lineinfo (Dwfl_Line *line, Dwarf_Addr *addr,
596 int *linep, int *colp,
597 Dwarf_Word *mtime, Dwarf_Word *length);
599 /* Return the equivalent Dwarf_Line and the bias to apply to its address. */
600 extern Dwarf_Line *dwfl_dwarf_line (Dwfl_Line *line, Dwarf_Addr *bias);
602 /* Return the compilation directory (AT_comp_dir) from this line's CU. */
603 extern const char *dwfl_line_comp_dir (Dwfl_Line *line);
606 /*** Machine backend access functions ***/
608 /* Return location expression to find return value given a
609 DW_TAG_subprogram, DW_TAG_subroutine_type, or similar DIE describing
610 function itself (whose DW_AT_type attribute describes its return type).
611 The given DIE must come from the given module. Returns -1 for errors.
612 Returns zero if the function has no return value (e.g. "void" in C).
613 Otherwise, *LOCOPS gets a location expression to find the return value,
614 and returns the number of operations in the expression. The pointer is
615 permanently allocated at least as long as the module is live. */
616 extern int dwfl_module_return_value_location (Dwfl_Module *mod,
617 Dwarf_Die *functypedie,
618 const Dwarf_Op **locops);
620 /* Enumerate the DWARF register numbers and their names.
621 For each register, CALLBACK gets its DWARF number, a string describing
622 the register set (such as "integer" or "FPU"), a prefix used in
623 assembler syntax (such as "%" or "$", may be ""), and the name for the
624 register (contains identifier characters only, possibly all digits).
625 The REGNAME string is valid only during the callback. */
626 extern int dwfl_module_register_names (Dwfl_Module *mod,
627 int (*callback) (void *arg,
636 /* Find the CFI for this module. Returns NULL if there is no CFI.
637 On success, fills in *BIAS with the difference between addresses
638 within the loaded module and those in the CFI referring to it.
639 The pointer returned can be used until the module is cleaned up.
640 Calling these more than once returns the same pointers.
642 dwfl_module_dwarf_cfi gets the '.debug_frame' information found with the
643 rest of the DWARF information. dwfl_module_eh_cfi gets the '.eh_frame'
644 information found linked into the text. A module might have either or
646 extern Dwarf_CFI *dwfl_module_dwarf_cfi (Dwfl_Module *mod, Dwarf_Addr *bias);
647 extern Dwarf_CFI *dwfl_module_eh_cfi (Dwfl_Module *mod, Dwarf_Addr *bias);
652 /* Called to iterate through threads. Returns next TID (thread ID) on
653 success, a negative number on failure and zero if there are no more
654 threads. dwfl_errno () should be set if negative number has been
655 returned. *THREAD_ARGP is NULL on first call, and may be optionally
656 set by the implementation. The value set by the implementation will
657 be passed in on the next call to NEXT_THREAD. THREAD_ARGP is never
658 NULL. *THREAD_ARGP will be passed to set_initial_registers or
659 thread_detach callbacks together with Dwfl_Thread *thread. This
660 method must not be NULL. */
661 pid_t (*next_thread) (Dwfl *dwfl, void *dwfl_arg, void **thread_argp)
662 __nonnull_attribute__ (1);
664 /* Called to get a specific thread. Returns true if there is a
665 thread with the given thread id number, returns false if no such
666 thread exists and will set dwfl_errno in that case. THREAD_ARGP
667 is never NULL. *THREAD_ARGP will be passed to
668 set_initial_registers or thread_detach callbacks together with
669 Dwfl_Thread *thread. This method may be NULL and will then be
670 emulated using the next_thread callback. */
671 bool (*get_thread) (Dwfl *dwfl, pid_t tid, void *dwfl_arg,
673 __nonnull_attribute__ (1);
675 /* Called during unwinding to access memory (stack) state. Returns true for
676 successfully read *RESULT or false and sets dwfl_errno () on failure.
677 This method may be NULL - in such case dwfl_thread_getframes will return
678 only the initial frame. */
679 bool (*memory_read) (Dwfl *dwfl, Dwarf_Addr addr, Dwarf_Word *result,
681 __nonnull_attribute__ (1, 3);
683 /* Called on initial unwind to get the initial register state of the first
684 frame. Should call dwfl_thread_state_registers, possibly multiple times
685 for different ranges and possibly also dwfl_thread_state_register_pc, to
686 fill in initial (DWARF) register values. After this call, till at least
687 thread_detach is called, the thread is assumed to be frozen, so that it is
688 safe to unwind. Returns true on success or false and sets dwfl_errno ()
689 on failure. In the case of a failure thread_detach will not be called.
690 This method must not be NULL. */
691 bool (*set_initial_registers) (Dwfl_Thread *thread, void *thread_arg)
692 __nonnull_attribute__ (1);
694 /* Called by dwfl_end. All thread_detach method calls have been already
695 done. This method may be NULL. */
696 void (*detach) (Dwfl *dwfl, void *dwfl_arg)
697 __nonnull_attribute__ (1);
699 /* Called when unwinding is done. No callback will be called after
700 this method has been called. Iff set_initial_registers was called for
701 a TID and it returned success thread_detach will be called before the
702 detach method above. This method may be NULL. */
703 void (*thread_detach) (Dwfl_Thread *thread, void *thread_arg)
704 __nonnull_attribute__ (1);
705 } Dwfl_Thread_Callbacks;
707 /* PID is the process id associated with the DWFL state. Architecture of DWFL
708 modules is specified by ELF, ELF must remain valid during DWFL lifetime.
709 Use NULL ELF to detect architecture from DWFL, the function will then detect
710 it from arbitrary Dwfl_Module of DWFL. DWFL_ARG is the callback backend
711 state. DWFL_ARG will be provided to the callbacks. *THREAD_CALLBACKS
712 function pointers must remain valid during lifetime of DWFL. Function
713 returns true on success, false otherwise. */
714 bool dwfl_attach_state (Dwfl *dwfl, Elf *elf, pid_t pid,
715 const Dwfl_Thread_Callbacks *thread_callbacks,
717 __nonnull_attribute__ (1, 4);
719 /* Calls dwfl_attach_state with Dwfl_Thread_Callbacks setup for extracting
720 thread state from the ELF core file. Returns the pid number extracted
721 from the core file, or -1 for errors. */
722 extern int dwfl_core_file_attach (Dwfl *dwfl, Elf *elf);
724 /* Calls dwfl_attach_state with Dwfl_Thread_Callbacks setup for extracting
725 thread state from the proc file system. Uses ptrace to attach and stop
726 the thread under inspection and detaches when thread_detach is called
727 and unwinding for the thread is done, unless ASSUME_PTRACE_STOPPED is
728 true. If ASSUME_PTRACE_STOPPED is true the caller should make sure that
729 the thread is ptrace attached and stopped before unwinding by calling
730 either dwfl_thread_getframes or dwfl_getthread_frames. Returns zero on
731 success, -1 if dwfl_attach_state failed, or an errno code if opening the
732 proc files failed. */
733 extern int dwfl_linux_proc_attach (Dwfl *dwfl, pid_t pid,
734 bool assume_ptrace_stopped);
736 /* Return PID for the process associated with DWFL. Function returns -1 if
737 dwfl_attach_state was not called for DWFL. */
738 pid_t dwfl_pid (Dwfl *dwfl)
739 __nonnull_attribute__ (1);
741 /* Return DWFL from which THREAD was created using dwfl_getthreads. */
742 Dwfl *dwfl_thread_dwfl (Dwfl_Thread *thread)
743 __nonnull_attribute__ (1);
745 /* Return positive TID (thread ID) for THREAD. This function never fails. */
746 pid_t dwfl_thread_tid (Dwfl_Thread *thread)
747 __nonnull_attribute__ (1);
749 /* Return thread for frame STATE. This function never fails. */
750 Dwfl_Thread *dwfl_frame_thread (Dwfl_Frame *state)
751 __nonnull_attribute__ (1);
753 /* Called by Dwfl_Thread_Callbacks.set_initial_registers implementation.
754 For every known continuous block of registers <FIRSTREG..FIRSTREG+NREGS)
755 (inclusive..exclusive) set their content to REGS (array of NREGS items).
756 Function returns false if any of the registers has invalid number. */
757 bool dwfl_thread_state_registers (Dwfl_Thread *thread, int firstreg,
758 unsigned nregs, const Dwarf_Word *regs)
759 __nonnull_attribute__ (1, 4);
761 /* Called by Dwfl_Thread_Callbacks.set_initial_registers implementation.
762 If PC is not contained among DWARF registers passed by
763 dwfl_thread_state_registers on the target architecture pass the PC value
765 void dwfl_thread_state_register_pc (Dwfl_Thread *thread, Dwarf_Word pc)
766 __nonnull_attribute__ (1);
768 /* Iterate through the threads for a process. Returns zero if all threads have
769 been processed by the callback, returns -1 on error, or the value of the
770 callback when not DWARF_CB_OK. -1 returned on error will set dwfl_errno ().
771 Keeps calling the callback with the next thread while the callback returns
772 DWARF_CB_OK, till there are no more threads. */
773 int dwfl_getthreads (Dwfl *dwfl,
774 int (*callback) (Dwfl_Thread *thread, void *arg),
776 __nonnull_attribute__ (1, 2);
778 /* Iterate through the frames for a thread. Returns zero if all frames
779 have been processed by the callback, returns -1 on error, or the value of
780 the callback when not DWARF_CB_OK. -1 returned on error will
781 set dwfl_errno (). Some systems return error instead of zero on end of the
782 backtrace, for cross-platform compatibility callers should consider error as
783 a zero. Keeps calling the callback with the next frame while the callback
784 returns DWARF_CB_OK, till there are no more frames. On start will call the
785 set_initial_registers callback and on return will call the detach_thread
786 callback of the Dwfl_Thread. */
787 int dwfl_thread_getframes (Dwfl_Thread *thread,
788 int (*callback) (Dwfl_Frame *state, void *arg),
790 __nonnull_attribute__ (1, 2);
792 /* Like dwfl_thread_getframes, but specifying the thread by its unique
793 identifier number. Returns zero if all frames have been processed
794 by the callback, returns -1 on error (and when no thread with
795 the given thread id number exists), or the value of the callback
796 when not DWARF_CB_OK. -1 returned on error will set dwfl_errno (). */
797 int dwfl_getthread_frames (Dwfl *dwfl, pid_t tid,
798 int (*callback) (Dwfl_Frame *thread, void *arg),
800 __nonnull_attribute__ (1, 3);
802 /* Return *PC (program counter) for thread-specific frame STATE.
803 Set *ISACTIVATION according to DWARF frame "activation" definition.
804 Typically you need to substract 1 from *PC if *ACTIVATION is false to safely
805 find function of the caller. ACTIVATION may be NULL. PC must not be NULL.
806 Function returns false if it failed to find *PC. */
807 bool dwfl_frame_pc (Dwfl_Frame *state, Dwarf_Addr *pc, bool *isactivation)
808 __nonnull_attribute__ (1, 2);
814 #endif /* libdwfl.h */