1 /* Shared library support for IRIX.
2 Copyright 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002
3 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 2 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, write to the Free Software
22 Foundation, Inc., 59 Temple Place - Suite 330,
23 Boston, MA 02111-1307, USA. */
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 or
127 extract_address seems simpler. */
130 extract_mips_address (void *addr, int len)
133 return extract_signed_integer (addr, len);
135 return extract_address (addr, len);
138 /* Fetch and return the link map data associated with ADDR. Note that
139 this routine automatically determines which (of three) link map
140 formats is in use by the target. */
143 fetch_lm_info (CORE_ADDR addr)
146 union irix_obj_info buf;
150 /* The smallest region that we'll need is for buf.ol32. We'll read
151 that first. We'll read more of the buffer later if we have to deal
152 with one of the other cases. (We don't want to incur a memory error
153 if we were to read a larger region that generates an error due to
154 being at the end of a page or the like.) */
155 read_memory (addr, (char *) &buf, sizeof (buf.ol32));
157 if (extract_unsigned_integer (&buf.magic, sizeof (buf.magic)) != 0xffffffff)
159 /* Use buf.ol32... */
161 CORE_ADDR obj_addr = extract_mips_address (&buf.ol32.data,
162 sizeof (buf.ol32.data));
163 li.next = extract_mips_address (&buf.ol32.next, sizeof (buf.ol32.next));
165 read_memory (obj_addr, obj_buf, sizeof (obj_buf));
167 li.pathname_addr = extract_mips_address (&obj_buf[236], 4);
168 li.pathname_len = 0; /* unknown */
169 li.reloc_offset = extract_mips_address (&obj_buf[196], 4)
170 - extract_mips_address (&obj_buf[248], 4);
173 else if (extract_unsigned_integer (&buf.oi32.oi_size,
174 sizeof (buf.oi32.oi_size))
175 == sizeof (buf.oi32))
177 /* Use buf.oi32... */
179 /* Read rest of buffer. */
180 read_memory (addr + sizeof (buf.ol32),
181 ((char *) &buf) + sizeof (buf.ol32),
182 sizeof (buf.oi32) - sizeof (buf.ol32));
184 /* Fill in fields using buffer contents. */
185 li.next = extract_mips_address (&buf.oi32.oi_next,
186 sizeof (buf.oi32.oi_next));
187 li.reloc_offset = extract_mips_address (&buf.oi32.oi_ehdr,
188 sizeof (buf.oi32.oi_ehdr))
189 - extract_mips_address (&buf.oi32.oi_orig_ehdr,
190 sizeof (buf.oi32.oi_orig_ehdr));
191 li.pathname_addr = extract_mips_address (&buf.oi32.oi_pathname,
192 sizeof (buf.oi32.oi_pathname));
193 li.pathname_len = extract_unsigned_integer (&buf.oi32.oi_pathname_len,
197 else if (extract_unsigned_integer (&buf.oi64.oi_size,
198 sizeof (buf.oi64.oi_size))
199 == sizeof (buf.oi64))
201 /* Use buf.oi64... */
203 /* Read rest of buffer. */
204 read_memory (addr + sizeof (buf.ol32),
205 ((char *) &buf) + sizeof (buf.ol32),
206 sizeof (buf.oi64) - sizeof (buf.ol32));
208 /* Fill in fields using buffer contents. */
209 li.next = extract_mips_address (&buf.oi64.oi_next,
210 sizeof (buf.oi64.oi_next));
211 li.reloc_offset = extract_mips_address (&buf.oi64.oi_ehdr,
212 sizeof (buf.oi64.oi_ehdr))
213 - extract_mips_address (&buf.oi64.oi_orig_ehdr,
214 sizeof (buf.oi64.oi_orig_ehdr));
215 li.pathname_addr = extract_mips_address (&buf.oi64.oi_pathname,
216 sizeof (buf.oi64.oi_pathname));
217 li.pathname_len = extract_unsigned_integer (&buf.oi64.oi_pathname_len,
223 error ("Unable to fetch shared library obj_info or obj_list info.");
229 /* The symbol which starts off the list of shared libraries. */
230 #define DEBUG_BASE "__rld_obj_head"
232 char shadow_contents[BREAKPOINT_MAX]; /* Stash old bkpt addr contents */
234 static CORE_ADDR debug_base; /* Base of dynamic linker structures */
235 static CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */
241 locate_base -- locate the base address of dynamic linker structs
245 CORE_ADDR locate_base (void)
249 For both the SunOS and SVR4 shared library implementations, if the
250 inferior executable has been linked dynamically, there is a single
251 address somewhere in the inferior's data space which is the key to
252 locating all of the dynamic linker's runtime structures. This
253 address is the value of the symbol defined by the macro DEBUG_BASE.
254 The job of this function is to find and return that address, or to
255 return 0 if there is no such address (the executable is statically
258 For SunOS, the job is almost trivial, since the dynamic linker and
259 all of it's structures are statically linked to the executable at
260 link time. Thus the symbol for the address we are looking for has
261 already been added to the minimal symbol table for the executable's
262 objfile at the time the symbol file's symbols were read, and all we
263 have to do is look it up there. Note that we explicitly do NOT want
264 to find the copies in the shared library.
266 The SVR4 version is much more complicated because the dynamic linker
267 and it's structures are located in the shared C library, which gets
268 run as the executable's "interpreter" by the kernel. We have to go
269 to a lot more work to discover the address of DEBUG_BASE. Because
270 of this complexity, we cache the value we find and return that value
271 on subsequent invocations. Note there is no copy in the executable
274 Irix 5 is basically like SunOS.
276 Note that we can assume nothing about the process state at the time
277 we need to find this address. We may be stopped on the first instruc-
278 tion of the interpreter (C shared library), the first instruction of
279 the executable itself, or somewhere else entirely (if we attached
280 to the process for example).
287 struct minimal_symbol *msymbol;
288 CORE_ADDR address = 0;
290 msymbol = lookup_minimal_symbol (DEBUG_BASE, NULL, symfile_objfile);
291 if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
293 address = SYMBOL_VALUE_ADDRESS (msymbol);
302 disable_break -- remove the "mapping changed" breakpoint
306 static int disable_break ()
310 Removes the breakpoint that gets hit when the dynamic linker
311 completes a mapping change.
321 /* Note that breakpoint address and original contents are in our address
322 space, so we just need to write the original contents back. */
324 if (memory_remove_breakpoint (breakpoint_addr, shadow_contents) != 0)
329 /* For the SVR4 version, we always know the breakpoint address. For the
330 SunOS version we don't know it until the above code is executed.
331 Grumble if we are stopped anywhere besides the breakpoint address. */
333 if (stop_pc != breakpoint_addr)
336 ("stopped at unknown breakpoint while handling shared libraries");
346 enable_break -- arrange for dynamic linker to hit breakpoint
350 int enable_break (void)
354 This functions inserts a breakpoint at the entry point of the
355 main executable, where all shared libraries are mapped in.
361 if (symfile_objfile != NULL
362 && target_insert_breakpoint (symfile_objfile->ei.entry_point,
363 shadow_contents) == 0)
365 breakpoint_addr = symfile_objfile->ei.entry_point;
376 irix_solib_create_inferior_hook -- shared library startup support
380 void solib_create_inferior_hook()
384 When gdb starts up the inferior, it nurses it along (through the
385 shell) until it is ready to execute it's first instruction. At this
386 point, this function gets called via expansion of the macro
387 SOLIB_CREATE_INFERIOR_HOOK.
389 For SunOS executables, this first instruction is typically the
390 one at "_start", or a similar text label, regardless of whether
391 the executable is statically or dynamically linked. The runtime
392 startup code takes care of dynamically linking in any shared
393 libraries, once gdb allows the inferior to continue.
395 For SVR4 executables, this first instruction is either the first
396 instruction in the dynamic linker (for dynamically linked
397 executables) or the instruction at "start" for statically linked
398 executables. For dynamically linked executables, the system
399 first exec's /lib/libc.so.N, which contains the dynamic linker,
400 and starts it running. The dynamic linker maps in any needed
401 shared libraries, maps in the actual user executable, and then
402 jumps to "start" in the user executable.
404 For both SunOS shared libraries, and SVR4 shared libraries, we
405 can arrange to cooperate with the dynamic linker to discover the
406 names of shared libraries that are dynamically linked, and the
407 base addresses to which they are linked.
409 This function is responsible for discovering those names and
410 addresses, and saving sufficient information about them to allow
411 their symbols to be read at a later time.
415 Between enable_break() and disable_break(), this code does not
416 properly handle hitting breakpoints which the user might have
417 set in the startup code or in the dynamic linker itself. Proper
418 handling will probably have to wait until the implementation is
419 changed to use the "breakpoint handler function" method.
421 Also, what if child has exit()ed? Must exit loop somehow.
425 irix_solib_create_inferior_hook (void)
427 if (!enable_break ())
429 warning ("shared library handler failed to enable breakpoint");
433 /* Now run the target. It will eventually hit the breakpoint, at
434 which point all of the libraries will have been mapped in and we
435 can go groveling around in the dynamic linker structures to find
436 out what we need to know about them. */
438 clear_proceed_status ();
439 stop_soon_quietly = 1;
440 stop_signal = TARGET_SIGNAL_0;
443 target_resume (pid_to_ptid (-1), 0, stop_signal);
444 wait_for_inferior ();
446 while (stop_signal != TARGET_SIGNAL_TRAP);
448 /* We are now either at the "mapping complete" breakpoint (or somewhere
449 else, a condition we aren't prepared to deal with anyway), so adjust
450 the PC as necessary after a breakpoint, disable the breakpoint, and
451 add any shared libraries that were mapped in. */
453 if (!disable_break ())
455 warning ("shared library handler failed to disable breakpoint");
458 /* solib_add will call reinit_frame_cache.
459 But we are stopped in the startup code and we might not have symbols
460 for the startup code, so heuristic_proc_start could be called
461 and will put out an annoying warning.
462 Delaying the resetting of stop_soon_quietly until after symbol loading
463 suppresses the warning. */
464 solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
465 stop_soon_quietly = 0;
466 re_enable_breakpoints_in_shlibs ();
471 current_sos -- build a list of currently loaded shared objects
475 struct so_list *current_sos ()
479 Build a list of `struct so_list' objects describing the shared
480 objects currently loaded in the inferior. This list does not
481 include an entry for the main executable file.
483 Note that we only gather information directly available from the
484 inferior --- we don't examine any of the shared library files
485 themselves. The declaration of `struct so_list' says which fields
486 we provide values for. */
488 static struct so_list *
489 irix_current_sos (void)
493 struct so_list *head = 0;
494 struct so_list **link_ptr = &head;
498 /* Make sure we've looked up the inferior's dynamic linker's base
502 debug_base = locate_base ();
504 /* If we can't find the dynamic linker's base structure, this
505 must not be a dynamically linked executable. Hmm. */
510 read_memory (debug_base, addr_buf, TARGET_ADDR_BIT / TARGET_CHAR_BIT);
511 lma = extract_mips_address (addr_buf, TARGET_ADDR_BIT / TARGET_CHAR_BIT);
515 lm = fetch_lm_info (lma);
522 = (struct so_list *) xmalloc (sizeof (struct so_list));
523 struct cleanup *old_chain = make_cleanup (xfree, new);
525 memset (new, 0, sizeof (*new));
527 new->lm_info = xmalloc (sizeof (struct lm_info));
528 make_cleanup (xfree, new->lm_info);
532 /* Extract this shared object's name. */
533 name_size = lm.pathname_len;
535 name_size = SO_NAME_MAX_PATH_SIZE - 1;
537 if (name_size >= SO_NAME_MAX_PATH_SIZE)
539 name_size = SO_NAME_MAX_PATH_SIZE - 1;
541 ("current_sos: truncating name of %d characters to only %d characters",
542 lm.pathname_len, name_size);
545 target_read_string (lm.pathname_addr, &name_buf,
546 name_size, &errcode);
549 warning ("current_sos: Can't read pathname for load map: %s\n",
550 safe_strerror (errcode));
554 strncpy (new->so_name, name_buf, name_size);
555 new->so_name[name_size] = '\0';
557 strcpy (new->so_original_name, new->so_name);
562 link_ptr = &new->next;
564 discard_cleanups (old_chain);
577 irix_open_symbol_file_object
581 void irix_open_symbol_file_object (void *from_tty)
585 If no open symbol file, attempt to locate and open the main symbol
586 file. On IRIX, this is the first link map entry. If its name is
587 here, we can open it. Useful when attaching to a process without
588 first loading its symbol file.
590 If FROM_TTYP dereferences to a non-zero integer, allow messages to
591 be printed. This parameter is a pointer rather than an int because
592 open_symbol_file_object() is called via catch_errors() and
593 catch_errors() requires a pointer argument. */
596 irix_open_symbol_file_object (void *from_ttyp)
601 struct cleanup *cleanups;
603 int from_tty = *(int *) from_ttyp;
607 if (!query ("Attempt to reload symbols from process? "))
610 if ((debug_base = locate_base ()) == 0)
611 return 0; /* failed somehow... */
613 /* First link map member should be the executable. */
614 read_memory (debug_base, addr_buf, TARGET_ADDR_BIT / TARGET_CHAR_BIT);
615 lma = extract_mips_address (addr_buf, TARGET_ADDR_BIT / TARGET_CHAR_BIT);
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;