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