1 /* Shared library support for IRIX.
2 Copyright (C) 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2004,
3 2007 Free Software Foundation, Inc.
5 This file was created using portions of irix5-nat.c originally
6 contributed to GDB by Ian Lance Taylor.
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
27 /* FIXME: ezannoni/2004-02-13 Verify that the include below is
37 /* Link map info to include in an allocate so_list entry. Unlike some
38 of the other solib backends, this (Irix) backend chooses to decode
39 the link map info obtained from the target and store it as (mostly)
40 CORE_ADDRs which need no further decoding. This is more convenient
41 because there are three different link map formats to worry about.
42 We use a single routine (fetch_lm_info) to read (and decode) the target
43 specific link map data. */
47 CORE_ADDR addr; /* address of obj_info or obj_list
48 struct on target (from which the
49 following information is obtained). */
50 CORE_ADDR next; /* address of next item in list. */
51 CORE_ADDR reloc_offset; /* amount to relocate by */
52 CORE_ADDR pathname_addr; /* address of pathname */
53 int pathname_len; /* length of pathname */
56 /* It's not desirable to use the system header files to obtain the
57 structure of the obj_list or obj_info structs. Therefore, we use a
58 platform neutral representation which has been derived from the IRIX
72 /* The "old" obj_list struct. This is used with old (o32) binaries.
73 The ``data'' member points at a much larger and more complicated
74 struct which we will only refer to by offsets. See
84 /* The ELF32 and ELF64 versions of the above struct. The oi_magic value
85 corresponds to the ``data'' value in the "old" struct. When this value
86 is 0xffffffff, the data will be in one of the following formats. The
87 ``oi_size'' field is used to decide which one we actually have. */
89 struct irix_elf32_obj_info
91 gdb_int32_bytes oi_magic;
92 gdb_int32_bytes oi_size;
93 gdb_int32_bytes oi_next;
94 gdb_int32_bytes oi_prev;
95 gdb_int32_bytes oi_ehdr;
96 gdb_int32_bytes oi_orig_ehdr;
97 gdb_int32_bytes oi_pathname;
98 gdb_int32_bytes oi_pathname_len;
101 struct irix_elf64_obj_info
103 gdb_int32_bytes oi_magic;
104 gdb_int32_bytes oi_size;
105 gdb_int64_bytes oi_next;
106 gdb_int64_bytes oi_prev;
107 gdb_int64_bytes oi_ehdr;
108 gdb_int64_bytes oi_orig_ehdr;
109 gdb_int64_bytes oi_pathname;
110 gdb_int32_bytes oi_pathname_len;
111 gdb_int32_bytes padding;
114 /* Union of all of the above (plus a split out magic field). */
118 gdb_int32_bytes magic;
119 struct irix_obj_list ol32;
120 struct irix_elf32_obj_info oi32;
121 struct irix_elf64_obj_info oi64;
124 /* MIPS sign extends its 32 bit addresses. We could conceivably use
125 extract_typed_address here, but to do so, we'd have to construct an
126 appropriate type. Calling extract_signed_integer seems simpler. */
129 extract_mips_address (void *addr, int len)
131 return extract_signed_integer (addr, len);
134 /* Fetch and return the link map data associated with ADDR. Note that
135 this routine automatically determines which (of three) link map
136 formats is in use by the target. */
139 fetch_lm_info (CORE_ADDR addr)
142 union irix_obj_info buf;
146 /* The smallest region that we'll need is for buf.ol32. We'll read
147 that first. We'll read more of the buffer later if we have to deal
148 with one of the other cases. (We don't want to incur a memory error
149 if we were to read a larger region that generates an error due to
150 being at the end of a page or the like.) */
151 read_memory (addr, (char *) &buf, sizeof (buf.ol32));
153 if (extract_unsigned_integer (buf.magic.b, sizeof (buf.magic)) != 0xffffffff)
155 /* Use buf.ol32... */
157 CORE_ADDR obj_addr = extract_mips_address (&buf.ol32.data,
158 sizeof (buf.ol32.data));
159 li.next = extract_mips_address (&buf.ol32.next, sizeof (buf.ol32.next));
161 read_memory (obj_addr, obj_buf, sizeof (obj_buf));
163 li.pathname_addr = extract_mips_address (&obj_buf[236], 4);
164 li.pathname_len = 0; /* unknown */
165 li.reloc_offset = extract_mips_address (&obj_buf[196], 4)
166 - extract_mips_address (&obj_buf[248], 4);
169 else if (extract_unsigned_integer (buf.oi32.oi_size.b,
170 sizeof (buf.oi32.oi_size))
171 == sizeof (buf.oi32))
173 /* Use buf.oi32... */
175 /* Read rest of buffer. */
176 read_memory (addr + sizeof (buf.ol32),
177 ((char *) &buf) + sizeof (buf.ol32),
178 sizeof (buf.oi32) - sizeof (buf.ol32));
180 /* Fill in fields using buffer contents. */
181 li.next = extract_mips_address (&buf.oi32.oi_next,
182 sizeof (buf.oi32.oi_next));
183 li.reloc_offset = extract_mips_address (&buf.oi32.oi_ehdr,
184 sizeof (buf.oi32.oi_ehdr))
185 - extract_mips_address (&buf.oi32.oi_orig_ehdr,
186 sizeof (buf.oi32.oi_orig_ehdr));
187 li.pathname_addr = extract_mips_address (&buf.oi32.oi_pathname,
188 sizeof (buf.oi32.oi_pathname));
189 li.pathname_len = extract_unsigned_integer (buf.oi32.oi_pathname_len.b,
193 else if (extract_unsigned_integer (buf.oi64.oi_size.b,
194 sizeof (buf.oi64.oi_size))
195 == sizeof (buf.oi64))
197 /* Use buf.oi64... */
199 /* Read rest of buffer. */
200 read_memory (addr + sizeof (buf.ol32),
201 ((char *) &buf) + sizeof (buf.ol32),
202 sizeof (buf.oi64) - sizeof (buf.ol32));
204 /* Fill in fields using buffer contents. */
205 li.next = extract_mips_address (&buf.oi64.oi_next,
206 sizeof (buf.oi64.oi_next));
207 li.reloc_offset = extract_mips_address (&buf.oi64.oi_ehdr,
208 sizeof (buf.oi64.oi_ehdr))
209 - extract_mips_address (&buf.oi64.oi_orig_ehdr,
210 sizeof (buf.oi64.oi_orig_ehdr));
211 li.pathname_addr = extract_mips_address (&buf.oi64.oi_pathname,
212 sizeof (buf.oi64.oi_pathname));
213 li.pathname_len = extract_unsigned_integer (buf.oi64.oi_pathname_len.b,
219 error (_("Unable to fetch shared library obj_info or obj_list info."));
225 /* The symbol which starts off the list of shared libraries. */
226 #define DEBUG_BASE "__rld_obj_head"
228 static void *base_breakpoint;
230 static CORE_ADDR debug_base; /* Base of dynamic linker structures */
236 locate_base -- locate the base address of dynamic linker structs
240 CORE_ADDR locate_base (void)
244 For both the SunOS and SVR4 shared library implementations, if the
245 inferior executable has been linked dynamically, there is a single
246 address somewhere in the inferior's data space which is the key to
247 locating all of the dynamic linker's runtime structures. This
248 address is the value of the symbol defined by the macro DEBUG_BASE.
249 The job of this function is to find and return that address, or to
250 return 0 if there is no such address (the executable is statically
253 For SunOS, the job is almost trivial, since the dynamic linker and
254 all of it's structures are statically linked to the executable at
255 link time. Thus the symbol for the address we are looking for has
256 already been added to the minimal symbol table for the executable's
257 objfile at the time the symbol file's symbols were read, and all we
258 have to do is look it up there. Note that we explicitly do NOT want
259 to find the copies in the shared library.
261 The SVR4 version is much more complicated because the dynamic linker
262 and it's structures are located in the shared C library, which gets
263 run as the executable's "interpreter" by the kernel. We have to go
264 to a lot more work to discover the address of DEBUG_BASE. Because
265 of this complexity, we cache the value we find and return that value
266 on subsequent invocations. Note there is no copy in the executable
269 Irix 5 is basically like SunOS.
271 Note that we can assume nothing about the process state at the time
272 we need to find this address. We may be stopped on the first instruc-
273 tion of the interpreter (C shared library), the first instruction of
274 the executable itself, or somewhere else entirely (if we attached
275 to the process for example).
282 struct minimal_symbol *msymbol;
283 CORE_ADDR address = 0;
285 msymbol = lookup_minimal_symbol (DEBUG_BASE, NULL, symfile_objfile);
286 if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
288 address = SYMBOL_VALUE_ADDRESS (msymbol);
297 disable_break -- remove the "mapping changed" breakpoint
301 static int disable_break ()
305 Removes the breakpoint that gets hit when the dynamic linker
306 completes a mapping change.
316 /* Note that breakpoint address and original contents are in our address
317 space, so we just need to write the original contents back. */
319 if (deprecated_remove_raw_breakpoint (base_breakpoint) != 0)
324 base_breakpoint = NULL;
326 /* Note that it is possible that we have stopped at a location that
327 is different from the location where we inserted our breakpoint.
328 On mips-irix, we can actually land in __dbx_init(), so we should
329 not check the PC against our breakpoint address here. See procfs.c
339 enable_break -- arrange for dynamic linker to hit breakpoint
343 int enable_break (void)
347 This functions inserts a breakpoint at the entry point of the
348 main executable, where all shared libraries are mapped in.
354 if (symfile_objfile != NULL)
357 = deprecated_insert_raw_breakpoint (entry_point_address ());
359 if (base_breakpoint != NULL)
370 irix_solib_create_inferior_hook -- shared library startup support
374 void solib_create_inferior_hook ()
378 When gdb starts up the inferior, it nurses it along (through the
379 shell) until it is ready to execute it's first instruction. At this
380 point, this function gets called via expansion of the macro
381 SOLIB_CREATE_INFERIOR_HOOK.
383 For SunOS executables, this first instruction is typically the
384 one at "_start", or a similar text label, regardless of whether
385 the executable is statically or dynamically linked. The runtime
386 startup code takes care of dynamically linking in any shared
387 libraries, once gdb allows the inferior to continue.
389 For SVR4 executables, this first instruction is either the first
390 instruction in the dynamic linker (for dynamically linked
391 executables) or the instruction at "start" for statically linked
392 executables. For dynamically linked executables, the system
393 first exec's /lib/libc.so.N, which contains the dynamic linker,
394 and starts it running. The dynamic linker maps in any needed
395 shared libraries, maps in the actual user executable, and then
396 jumps to "start" in the user executable.
398 For both SunOS shared libraries, and SVR4 shared libraries, we
399 can arrange to cooperate with the dynamic linker to discover the
400 names of shared libraries that are dynamically linked, and the
401 base addresses to which they are linked.
403 This function is responsible for discovering those names and
404 addresses, and saving sufficient information about them to allow
405 their symbols to be read at a later time.
409 Between enable_break() and disable_break(), this code does not
410 properly handle hitting breakpoints which the user might have
411 set in the startup code or in the dynamic linker itself. Proper
412 handling will probably have to wait until the implementation is
413 changed to use the "breakpoint handler function" method.
415 Also, what if child has exit()ed? Must exit loop somehow.
419 irix_solib_create_inferior_hook (void)
421 if (!enable_break ())
423 warning (_("shared library handler failed to enable breakpoint"));
427 /* Now run the target. It will eventually hit the breakpoint, at
428 which point all of the libraries will have been mapped in and we
429 can go groveling around in the dynamic linker structures to find
430 out what we need to know about them. */
432 clear_proceed_status ();
433 stop_soon = STOP_QUIETLY;
434 stop_signal = TARGET_SIGNAL_0;
437 target_resume (pid_to_ptid (-1), 0, stop_signal);
438 wait_for_inferior ();
440 while (stop_signal != TARGET_SIGNAL_TRAP);
442 /* We are now either at the "mapping complete" breakpoint (or somewhere
443 else, a condition we aren't prepared to deal with anyway), so adjust
444 the PC as necessary after a breakpoint, disable the breakpoint, and
445 add any shared libraries that were mapped in. */
447 if (!disable_break ())
449 warning (_("shared library handler failed to disable breakpoint"));
452 /* solib_add will call reinit_frame_cache.
453 But we are stopped in the startup code and we might not have symbols
454 for the startup code, so heuristic_proc_start could be called
455 and will put out an annoying warning.
456 Delaying the resetting of stop_soon until after symbol loading
457 suppresses the warning. */
458 solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
459 stop_soon = NO_STOP_QUIETLY;
460 re_enable_breakpoints_in_shlibs ();
465 current_sos -- build a list of currently loaded shared objects
469 struct so_list *current_sos ()
473 Build a list of `struct so_list' objects describing the shared
474 objects currently loaded in the inferior. This list does not
475 include an entry for the main executable file.
477 Note that we only gather information directly available from the
478 inferior --- we don't examine any of the shared library files
479 themselves. The declaration of `struct so_list' says which fields
480 we provide values for. */
482 static struct so_list *
483 irix_current_sos (void)
487 struct so_list *head = 0;
488 struct so_list **link_ptr = &head;
492 /* Make sure we've looked up the inferior's dynamic linker's base
496 debug_base = locate_base ();
498 /* If we can't find the dynamic linker's base structure, this
499 must not be a dynamically linked executable. Hmm. */
504 read_memory (debug_base,
506 gdbarch_addr_bit (current_gdbarch) / TARGET_CHAR_BIT);
507 lma = extract_mips_address (addr_buf,
508 gdbarch_addr_bit (current_gdbarch)
513 lm = fetch_lm_info (lma);
520 = (struct so_list *) xmalloc (sizeof (struct so_list));
521 struct cleanup *old_chain = make_cleanup (xfree, new);
523 memset (new, 0, sizeof (*new));
525 new->lm_info = xmalloc (sizeof (struct lm_info));
526 make_cleanup (xfree, new->lm_info);
530 /* Extract this shared object's name. */
531 name_size = lm.pathname_len;
533 name_size = SO_NAME_MAX_PATH_SIZE - 1;
535 if (name_size >= SO_NAME_MAX_PATH_SIZE)
537 name_size = SO_NAME_MAX_PATH_SIZE - 1;
539 ("current_sos: truncating name of %d characters to only %d characters",
540 lm.pathname_len, name_size);
543 target_read_string (lm.pathname_addr, &name_buf,
544 name_size, &errcode);
546 warning (_("Can't read pathname for load map: %s."),
547 safe_strerror (errcode));
550 strncpy (new->so_name, name_buf, name_size);
551 new->so_name[name_size] = '\0';
553 strcpy (new->so_original_name, new->so_name);
558 link_ptr = &new->next;
560 discard_cleanups (old_chain);
573 irix_open_symbol_file_object
577 void irix_open_symbol_file_object (void *from_tty)
581 If no open symbol file, attempt to locate and open the main symbol
582 file. On IRIX, this is the first link map entry. If its name is
583 here, we can open it. Useful when attaching to a process without
584 first loading its symbol file.
586 If FROM_TTYP dereferences to a non-zero integer, allow messages to
587 be printed. This parameter is a pointer rather than an int because
588 open_symbol_file_object() is called via catch_errors() and
589 catch_errors() requires a pointer argument. */
592 irix_open_symbol_file_object (void *from_ttyp)
597 struct cleanup *cleanups;
599 int from_tty = *(int *) from_ttyp;
603 if (!query ("Attempt to reload symbols from process? "))
606 if ((debug_base = locate_base ()) == 0)
607 return 0; /* failed somehow... */
609 /* First link map member should be the executable. */
610 read_memory (debug_base,
612 gdbarch_addr_bit (current_gdbarch) / TARGET_CHAR_BIT);
613 lma = extract_mips_address (addr_buf,
614 gdbarch_addr_bit (current_gdbarch)
617 return 0; /* failed somehow... */
619 lm = fetch_lm_info (lma);
621 if (lm.pathname_addr == 0)
622 return 0; /* No filename. */
624 /* Now fetch the filename from target memory. */
625 target_read_string (lm.pathname_addr, &filename, SO_NAME_MAX_PATH_SIZE - 1,
630 warning (_("failed to read exec filename from attached file: %s"),
631 safe_strerror (errcode));
635 cleanups = make_cleanup (xfree, filename);
636 /* Have a pathname: read the symbol file. */
637 symbol_file_add_main (filename, from_tty);
639 do_cleanups (cleanups);
649 irix_special_symbol_handling -- additional shared library symbol handling
653 void irix_special_symbol_handling ()
657 Once the symbols from a shared object have been loaded in the usual
658 way, we are called to do any system specific symbol handling that
661 For SunOS4, this consisted of grunging around in the dynamic
662 linkers structures to find symbol definitions for "common" symbols
663 and adding them to the minimal symbol table for the runtime common
666 However, for IRIX, there's nothing to do.
671 irix_special_symbol_handling (void)
675 /* Using the solist entry SO, relocate the addresses in SEC. */
678 irix_relocate_section_addresses (struct so_list *so,
679 struct section_table *sec)
681 sec->addr += so->lm_info->reloc_offset;
682 sec->endaddr += so->lm_info->reloc_offset;
685 /* Free the lm_info struct. */
688 irix_free_so (struct so_list *so)
693 /* Clear backend specific state. */
696 irix_clear_solib (void)
701 /* Return 1 if PC lies in the dynamic symbol resolution code of the
704 irix_in_dynsym_resolve_code (CORE_ADDR pc)
709 static struct target_so_ops irix_so_ops;
712 _initialize_irix_solib (void)
714 irix_so_ops.relocate_section_addresses = irix_relocate_section_addresses;
715 irix_so_ops.free_so = irix_free_so;
716 irix_so_ops.clear_solib = irix_clear_solib;
717 irix_so_ops.solib_create_inferior_hook = irix_solib_create_inferior_hook;
718 irix_so_ops.special_symbol_handling = irix_special_symbol_handling;
719 irix_so_ops.current_sos = irix_current_sos;
720 irix_so_ops.open_symbol_file_object = irix_open_symbol_file_object;
721 irix_so_ops.in_dynsym_resolve_code = irix_in_dynsym_resolve_code;
723 /* FIXME: Don't do this here. *_gdbarch_init() should set so_ops. */
724 current_target_so_ops = &irix_so_ops;