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

source code of include/elfutils/libdwfl.h