1 /* Handle SunOS shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
4 2001, 2004, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include <sys/types.h>
25 #include "gdb_string.h"
26 #include <sys/param.h>
29 /* SunOS shared libs need the nlist structure. */
39 #include "gdbthread.h"
44 /* The shared library implementation found on BSD a.out systems is
45 very similar to the SunOS implementation. However, the data
46 structures defined in <link.h> are named very differently. Make up
47 for those differences here. */
49 #ifdef HAVE_STRUCT_SO_MAP_WITH_SOM_MEMBERS
51 /* FIXME: Temporary until the equivalent defines have been removed
52 from all nm-*bsd*.h files. */
55 /* Map `struct link_map' and its members. */
56 #define link_map so_map
57 #define lm_addr som_addr
58 #define lm_name som_path
59 #define lm_next som_next
61 /* Map `struct link_dynamic_2' and its members. */
62 #define link_dynamic_2 section_dispatch_table
63 #define ld_loaded sdt_loaded
65 /* Map `struct rtc_symb' and its members. */
66 #define rtc_symb rt_symbol
68 #define rtc_next rt_next
70 /* Map `struct ld_debug' and its members. */
71 #define ld_debug so_debug
72 #define ldd_in_debugger dd_in_debugger
73 #define ldd_bp_addr dd_bpt_addr
74 #define ldd_bp_inst dd_bpt_shadow
77 /* Map `struct link_dynamic' and its members. */
78 #define link_dynamic _dynamic
79 #define ld_version d_version
88 /* Link map info to include in an allocated so_list entry. */
92 /* Pointer to copy of link map from inferior. The type is char *
93 rather than void *, so that we may use byte offsets to find the
94 various fields without the need for a cast. */
99 /* Symbols which are used to locate the base of the link map structures. */
101 static char *debug_base_symbols[] =
108 static char *main_name_list[] =
114 /* Macro to extract an address from a solib structure. When GDB is
115 configured for some 32-bit targets (e.g. Solaris 2.7 sparc), BFD is
116 configured to handle 64-bit targets, so CORE_ADDR is 64 bits. We
117 have to extract only the significant bits of addresses to get the
118 right address when accessing the core file BFD.
120 Assume that the address is unsigned. */
122 #define SOLIB_EXTRACT_ADDRESS(MEMBER) \
123 extract_unsigned_integer (&(MEMBER), sizeof (MEMBER), \
124 gdbarch_byte_order (target_gdbarch))
126 /* local data declarations */
128 static struct link_dynamic dynamic_copy;
129 static struct link_dynamic_2 ld_2_copy;
130 static struct ld_debug debug_copy;
131 static CORE_ADDR debug_addr;
132 static CORE_ADDR flag_addr;
135 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
137 #define fieldsize(TYPE, MEMBER) (sizeof (((TYPE *)0)->MEMBER))
139 /* link map access functions */
142 lm_addr (struct so_list *so)
144 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
145 int lm_addr_offset = offsetof (struct link_map, lm_addr);
146 int lm_addr_size = fieldsize (struct link_map, lm_addr);
148 return (CORE_ADDR) extract_signed_integer (so->lm_info->lm + lm_addr_offset,
149 lm_addr_size, byte_order);
153 lm_next (struct so_list *so)
155 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
156 int lm_next_offset = offsetof (struct link_map, lm_next);
157 int lm_next_size = fieldsize (struct link_map, lm_next);
159 /* Assume that the address is unsigned. */
160 return extract_unsigned_integer (so->lm_info->lm + lm_next_offset,
161 lm_next_size, byte_order);
165 lm_name (struct so_list *so)
167 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
168 int lm_name_offset = offsetof (struct link_map, lm_name);
169 int lm_name_size = fieldsize (struct link_map, lm_name);
171 /* Assume that the address is unsigned. */
172 return extract_unsigned_integer (so->lm_info->lm + lm_name_offset,
173 lm_name_size, byte_order);
176 static CORE_ADDR debug_base; /* Base of dynamic linker structures. */
178 /* Local function prototypes */
180 static int match_main (char *);
182 /* Allocate the runtime common object file. */
185 allocate_rt_common_objfile (void)
187 struct objfile *objfile;
188 struct objfile *last_one;
190 objfile = (struct objfile *) xmalloc (sizeof (struct objfile));
191 memset (objfile, 0, sizeof (struct objfile));
192 objfile->psymbol_cache = bcache_xmalloc ();
193 objfile->macro_cache = bcache_xmalloc ();
194 objfile->filename_cache = bcache_xmalloc ();
195 obstack_init (&objfile->objfile_obstack);
196 objfile->name = xstrdup ("rt_common");
198 /* Add this file onto the tail of the linked list of other such files. */
200 objfile->next = NULL;
201 if (object_files == NULL)
202 object_files = objfile;
205 for (last_one = object_files;
207 last_one = last_one->next);
208 last_one->next = objfile;
211 rt_common_objfile = objfile;
214 /* Read all dynamically loaded common symbol definitions from the inferior
215 and put them into the minimal symbol table for the runtime common
219 solib_add_common_symbols (CORE_ADDR rtc_symp)
221 struct rtc_symb inferior_rtc_symb;
222 struct nlist inferior_rtc_nlist;
226 /* Remove any runtime common symbols from previous runs. */
228 if (rt_common_objfile != NULL && rt_common_objfile->minimal_symbol_count)
230 obstack_free (&rt_common_objfile->objfile_obstack, 0);
231 obstack_init (&rt_common_objfile->objfile_obstack);
232 rt_common_objfile->minimal_symbol_count = 0;
233 rt_common_objfile->msymbols = NULL;
234 terminate_minimal_symbol_table (rt_common_objfile);
237 init_minimal_symbol_collection ();
238 make_cleanup_discard_minimal_symbols ();
242 read_memory (rtc_symp,
243 (char *) &inferior_rtc_symb,
244 sizeof (inferior_rtc_symb));
245 read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_sp),
246 (char *) &inferior_rtc_nlist,
247 sizeof (inferior_rtc_nlist));
248 if (inferior_rtc_nlist.n_type == N_COMM)
250 /* FIXME: The length of the symbol name is not available, but in the
251 current implementation the common symbol is allocated immediately
252 behind the name of the symbol. */
253 len = inferior_rtc_nlist.n_value - inferior_rtc_nlist.n_un.n_strx;
255 name = xmalloc (len);
256 read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_nlist.n_un.n_name),
259 /* Allocate the runtime common objfile if necessary. */
260 if (rt_common_objfile == NULL)
261 allocate_rt_common_objfile ();
263 prim_record_minimal_symbol (name, inferior_rtc_nlist.n_value,
264 mst_bss, rt_common_objfile);
267 rtc_symp = SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_next);
270 /* Install any minimal symbols that have been collected as the current
271 minimal symbols for the runtime common objfile. */
273 install_minimal_symbols (rt_common_objfile);
281 locate_base -- locate the base address of dynamic linker structs
285 CORE_ADDR locate_base (void)
289 For both the SunOS and SVR4 shared library implementations, if the
290 inferior executable has been linked dynamically, there is a single
291 address somewhere in the inferior's data space which is the key to
292 locating all of the dynamic linker's runtime structures. This
293 address is the value of the debug base symbol. The job of this
294 function is to find and return that address, or to return 0 if there
295 is no such address (the executable is statically linked for example).
297 For SunOS, the job is almost trivial, since the dynamic linker and
298 all of it's structures are statically linked to the executable at
299 link time. Thus the symbol for the address we are looking for has
300 already been added to the minimal symbol table for the executable's
301 objfile at the time the symbol file's symbols were read, and all we
302 have to do is look it up there. Note that we explicitly do NOT want
303 to find the copies in the shared library.
305 The SVR4 version is a bit more complicated because the address
306 is contained somewhere in the dynamic info section. We have to go
307 to a lot more work to discover the address of the debug base symbol.
308 Because of this complexity, we cache the value we find and return that
309 value on subsequent invocations. Note there is no copy in the
310 executable symbol tables.
317 struct minimal_symbol *msymbol;
318 CORE_ADDR address = 0;
321 /* For SunOS, we want to limit the search for the debug base symbol to the
322 executable being debugged, since there is a duplicate named symbol in the
323 shared library. We don't want the shared library versions. */
325 for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++)
327 msymbol = lookup_minimal_symbol (*symbolp, NULL, symfile_objfile);
328 if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
330 address = SYMBOL_VALUE_ADDRESS (msymbol);
341 first_link_map_member -- locate first member in dynamic linker's map
345 static CORE_ADDR first_link_map_member (void)
349 Find the first element in the inferior's dynamic link map, and
350 return its address in the inferior. This function doesn't copy the
351 link map entry itself into our address space; current_sos actually
355 first_link_map_member (void)
359 read_memory (debug_base, (char *) &dynamic_copy, sizeof (dynamic_copy));
360 if (dynamic_copy.ld_version >= 2)
362 /* It is a version that we can deal with, so read in the secondary
363 structure and find the address of the link map list from it. */
364 read_memory (SOLIB_EXTRACT_ADDRESS (dynamic_copy.ld_un.ld_2),
365 (char *) &ld_2_copy, sizeof (struct link_dynamic_2));
366 lm = SOLIB_EXTRACT_ADDRESS (ld_2_copy.ld_loaded);
372 open_symbol_file_object (void *from_ttyp)
380 current_sos -- build a list of currently loaded shared objects
384 struct so_list *current_sos ()
388 Build a list of `struct so_list' objects describing the shared
389 objects currently loaded in the inferior. This list does not
390 include an entry for the main executable file.
392 Note that we only gather information directly available from the
393 inferior --- we don't examine any of the shared library files
394 themselves. The declaration of `struct so_list' says which fields
395 we provide values for. */
397 static struct so_list *
398 sunos_current_sos (void)
401 struct so_list *head = 0;
402 struct so_list **link_ptr = &head;
406 /* Make sure we've looked up the inferior's dynamic linker's base
410 debug_base = locate_base ();
412 /* If we can't find the dynamic linker's base structure, this
413 must not be a dynamically linked executable. Hmm. */
418 /* Walk the inferior's link map list, and build our list of
419 `struct so_list' nodes. */
420 lm = first_link_map_member ();
424 = (struct so_list *) xmalloc (sizeof (struct so_list));
425 struct cleanup *old_chain = make_cleanup (xfree, new);
427 memset (new, 0, sizeof (*new));
429 new->lm_info = xmalloc (sizeof (struct lm_info));
430 make_cleanup (xfree, new->lm_info);
432 new->lm_info->lm = xmalloc (sizeof (struct link_map));
433 make_cleanup (xfree, new->lm_info->lm);
434 memset (new->lm_info->lm, 0, sizeof (struct link_map));
436 read_memory (lm, new->lm_info->lm, sizeof (struct link_map));
440 /* Extract this shared object's name. */
441 target_read_string (lm_name (new), &buffer,
442 SO_NAME_MAX_PATH_SIZE - 1, &errcode);
444 warning (_("Can't read pathname for load map: %s."),
445 safe_strerror (errcode));
448 strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1);
449 new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
451 strcpy (new->so_original_name, new->so_name);
454 /* If this entry has no name, or its name matches the name
455 for the main executable, don't include it in the list. */
456 if (! new->so_name[0]
457 || match_main (new->so_name))
463 link_ptr = &new->next;
466 discard_cleanups (old_chain);
473 /* On some systems, the only way to recognize the link map entry for
474 the main executable file is by looking at its name. Return
475 non-zero iff SONAME matches one of the known main executable names. */
478 match_main (char *soname)
482 for (mainp = main_name_list; *mainp != NULL; mainp++)
484 if (strcmp (soname, *mainp) == 0)
493 sunos_in_dynsym_resolve_code (CORE_ADDR pc)
502 disable_break -- remove the "mapping changed" breakpoint
506 static int disable_break ()
510 Removes the breakpoint that gets hit when the dynamic linker
511 completes a mapping change.
518 CORE_ADDR breakpoint_addr; /* Address where end bkpt is set. */
522 /* Read the debugger structure from the inferior to retrieve the
523 address of the breakpoint and the original contents of the
524 breakpoint address. Remove the breakpoint by writing the original
527 read_memory (debug_addr, (char *) &debug_copy, sizeof (debug_copy));
529 /* Set `in_debugger' to zero now. */
531 write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger));
533 breakpoint_addr = SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_bp_addr);
534 write_memory (breakpoint_addr, (char *) &debug_copy.ldd_bp_inst,
535 sizeof (debug_copy.ldd_bp_inst));
537 /* For the SVR4 version, we always know the breakpoint address. For the
538 SunOS version we don't know it until the above code is executed.
539 Grumble if we are stopped anywhere besides the breakpoint address. */
541 if (stop_pc != breakpoint_addr)
543 warning (_("stopped at unknown breakpoint "
544 "while handling shared libraries"));
555 enable_break -- arrange for dynamic linker to hit breakpoint
559 int enable_break (void)
563 Both the SunOS and the SVR4 dynamic linkers have, as part of their
564 debugger interface, support for arranging for the inferior to hit
565 a breakpoint after mapping in the shared libraries. This function
566 enables that breakpoint.
568 For SunOS, there is a special flag location (in_debugger) which we
569 set to 1. When the dynamic linker sees this flag set, it will set
570 a breakpoint at a location known only to itself, after saving the
571 original contents of that place and the breakpoint address itself,
572 in it's own internal structures. When we resume the inferior, it
573 will eventually take a SIGTRAP when it runs into the breakpoint.
574 We handle this (in a different place) by restoring the contents of
575 the breakpointed location (which is only known after it stops),
576 chasing around to locate the shared libraries that have been
577 loaded, then resuming.
579 For SVR4, the debugger interface structure contains a member (r_brk)
580 which is statically initialized at the time the shared library is
581 built, to the offset of a function (_r_debug_state) which is guaran-
582 teed to be called once before mapping in a library, and again when
583 the mapping is complete. At the time we are examining this member,
584 it contains only the unrelocated offset of the function, so we have
585 to do our own relocation. Later, when the dynamic linker actually
586 runs, it relocates r_brk to be the actual address of _r_debug_state().
588 The debugger interface structure also contains an enumeration which
589 is set to either RT_ADD or RT_DELETE prior to changing the mapping,
590 depending upon whether or not the library is being mapped or unmapped,
591 and then set to RT_CONSISTENT after the library is mapped/unmapped.
601 /* Get link_dynamic structure. */
603 j = target_read_memory (debug_base, (char *) &dynamic_copy,
604 sizeof (dynamic_copy));
611 /* Calc address of debugger interface structure. */
613 debug_addr = SOLIB_EXTRACT_ADDRESS (dynamic_copy.ldd);
615 /* Calc address of `in_debugger' member of debugger interface structure. */
617 flag_addr = debug_addr + (CORE_ADDR) ((char *) &debug_copy.ldd_in_debugger -
618 (char *) &debug_copy);
620 /* Write a value of 1 to this member. */
623 write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger));
633 special_symbol_handling -- additional shared library symbol handling
637 void special_symbol_handling ()
641 Once the symbols from a shared object have been loaded in the usual
642 way, we are called to do any system specific symbol handling that
645 For SunOS4, this consists of grunging around in the dynamic
646 linkers structures to find symbol definitions for "common" symbols
647 and adding them to the minimal symbol table for the runtime common
653 sunos_special_symbol_handling (void)
659 /* Get link_dynamic structure. */
661 j = target_read_memory (debug_base, (char *) &dynamic_copy,
662 sizeof (dynamic_copy));
669 /* Calc address of debugger interface structure. */
670 /* FIXME, this needs work for cross-debugging of core files
671 (byteorder, size, alignment, etc). */
673 debug_addr = SOLIB_EXTRACT_ADDRESS (dynamic_copy.ldd);
676 /* Read the debugger structure from the inferior, just to make sure
677 we have a current copy. */
679 j = target_read_memory (debug_addr, (char *) &debug_copy,
680 sizeof (debug_copy));
682 return; /* unreadable */
684 /* Get common symbol definitions for the loaded object. */
686 if (debug_copy.ldd_cp)
688 solib_add_common_symbols (SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_cp));
696 sunos_solib_create_inferior_hook -- shared library startup support
700 void sunos_solib_create_inferior_hook ()
704 When gdb starts up the inferior, it nurses it along (through the
705 shell) until it is ready to execute it's first instruction. At this
706 point, this function gets called via expansion of the macro
707 SOLIB_CREATE_INFERIOR_HOOK.
709 For SunOS executables, this first instruction is typically the
710 one at "_start", or a similar text label, regardless of whether
711 the executable is statically or dynamically linked. The runtime
712 startup code takes care of dynamically linking in any shared
713 libraries, once gdb allows the inferior to continue.
715 For SVR4 executables, this first instruction is either the first
716 instruction in the dynamic linker (for dynamically linked
717 executables) or the instruction at "start" for statically linked
718 executables. For dynamically linked executables, the system
719 first exec's /lib/libc.so.N, which contains the dynamic linker,
720 and starts it running. The dynamic linker maps in any needed
721 shared libraries, maps in the actual user executable, and then
722 jumps to "start" in the user executable.
724 For both SunOS shared libraries, and SVR4 shared libraries, we
725 can arrange to cooperate with the dynamic linker to discover the
726 names of shared libraries that are dynamically linked, and the
727 base addresses to which they are linked.
729 This function is responsible for discovering those names and
730 addresses, and saving sufficient information about them to allow
731 their symbols to be read at a later time.
735 Between enable_break() and disable_break(), this code does not
736 properly handle hitting breakpoints which the user might have
737 set in the startup code or in the dynamic linker itself. Proper
738 handling will probably have to wait until the implementation is
739 changed to use the "breakpoint handler function" method.
741 Also, what if child has exit()ed? Must exit loop somehow.
745 sunos_solib_create_inferior_hook (int from_tty)
747 struct thread_info *tp;
748 struct inferior *inf;
750 if ((debug_base = locate_base ()) == 0)
752 /* Can't find the symbol or the executable is statically linked. */
756 if (!enable_break ())
758 warning (_("shared library handler failed to enable breakpoint"));
762 /* SCO and SunOS need the loop below, other systems should be using the
763 special shared library breakpoints and the shared library breakpoint
766 Now run the target. It will eventually hit the breakpoint, at
767 which point all of the libraries will have been mapped in and we
768 can go groveling around in the dynamic linker structures to find
769 out what we need to know about them. */
771 inf = current_inferior ();
772 tp = inferior_thread ();
774 clear_proceed_status ();
776 inf->control.stop_soon = STOP_QUIETLY;
777 tp->suspend.stop_signal = TARGET_SIGNAL_0;
780 target_resume (pid_to_ptid (-1), 0, tp->suspend.stop_signal);
781 wait_for_inferior ();
783 while (tp->suspend.stop_signal != TARGET_SIGNAL_TRAP);
784 inf->control.stop_soon = NO_STOP_QUIETLY;
786 /* We are now either at the "mapping complete" breakpoint (or somewhere
787 else, a condition we aren't prepared to deal with anyway), so adjust
788 the PC as necessary after a breakpoint, disable the breakpoint, and
789 add any shared libraries that were mapped in.
791 Note that adjust_pc_after_break did not perform any PC adjustment,
792 as the breakpoint the inferior just hit was not inserted by GDB,
793 but by the dynamic loader itself, and is therefore not found on
794 the GDB software break point list. Thus we have to adjust the
797 if (gdbarch_decr_pc_after_break (target_gdbarch))
799 stop_pc -= gdbarch_decr_pc_after_break (target_gdbarch);
800 regcache_write_pc (get_current_regcache (), stop_pc);
803 if (!disable_break ())
805 warning (_("shared library handler failed to disable breakpoint"));
808 solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
812 sunos_clear_solib (void)
818 sunos_free_so (struct so_list *so)
820 xfree (so->lm_info->lm);
825 sunos_relocate_section_addresses (struct so_list *so,
826 struct target_section *sec)
828 sec->addr += lm_addr (so);
829 sec->endaddr += lm_addr (so);
832 static struct target_so_ops sunos_so_ops;
835 _initialize_sunos_solib (void)
837 sunos_so_ops.relocate_section_addresses = sunos_relocate_section_addresses;
838 sunos_so_ops.free_so = sunos_free_so;
839 sunos_so_ops.clear_solib = sunos_clear_solib;
840 sunos_so_ops.solib_create_inferior_hook = sunos_solib_create_inferior_hook;
841 sunos_so_ops.special_symbol_handling = sunos_special_symbol_handling;
842 sunos_so_ops.current_sos = sunos_current_sos;
843 sunos_so_ops.open_symbol_file_object = open_symbol_file_object;
844 sunos_so_ops.in_dynsym_resolve_code = sunos_in_dynsym_resolve_code;
845 sunos_so_ops.bfd_open = solib_bfd_open;
847 /* FIXME: Don't do this here. *_gdbarch_init() should set so_ops. */
848 current_target_so_ops = &sunos_so_ops;