1 /* Shared library support for IRIX.
2 Copyright (C) 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2004,
3 2007, 2008, 2009 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
34 #include "gdbthread.h"
38 #include "solib-irix.h"
41 /* Link map info to include in an allocate so_list entry. Unlike some
42 of the other solib backends, this (Irix) backend chooses to decode
43 the link map info obtained from the target and store it as (mostly)
44 CORE_ADDRs which need no further decoding. This is more convenient
45 because there are three different link map formats to worry about.
46 We use a single routine (fetch_lm_info) to read (and decode) the target
47 specific link map data. */
51 CORE_ADDR addr; /* address of obj_info or obj_list
52 struct on target (from which the
53 following information is obtained). */
54 CORE_ADDR next; /* address of next item in list. */
55 CORE_ADDR reloc_offset; /* amount to relocate by */
56 CORE_ADDR pathname_addr; /* address of pathname */
57 int pathname_len; /* length of pathname */
60 /* It's not desirable to use the system header files to obtain the
61 structure of the obj_list or obj_info structs. Therefore, we use a
62 platform neutral representation which has been derived from the IRIX
76 /* The "old" obj_list struct. This is used with old (o32) binaries.
77 The ``data'' member points at a much larger and more complicated
78 struct which we will only refer to by offsets. See
88 /* The ELF32 and ELF64 versions of the above struct. The oi_magic value
89 corresponds to the ``data'' value in the "old" struct. When this value
90 is 0xffffffff, the data will be in one of the following formats. The
91 ``oi_size'' field is used to decide which one we actually have. */
93 struct irix_elf32_obj_info
95 gdb_int32_bytes oi_magic;
96 gdb_int32_bytes oi_size;
97 gdb_int32_bytes oi_next;
98 gdb_int32_bytes oi_prev;
99 gdb_int32_bytes oi_ehdr;
100 gdb_int32_bytes oi_orig_ehdr;
101 gdb_int32_bytes oi_pathname;
102 gdb_int32_bytes oi_pathname_len;
105 struct irix_elf64_obj_info
107 gdb_int32_bytes oi_magic;
108 gdb_int32_bytes oi_size;
109 gdb_int64_bytes oi_next;
110 gdb_int64_bytes oi_prev;
111 gdb_int64_bytes oi_ehdr;
112 gdb_int64_bytes oi_orig_ehdr;
113 gdb_int64_bytes oi_pathname;
114 gdb_int32_bytes oi_pathname_len;
115 gdb_int32_bytes padding;
118 /* Union of all of the above (plus a split out magic field). */
122 gdb_int32_bytes magic;
123 struct irix_obj_list ol32;
124 struct irix_elf32_obj_info oi32;
125 struct irix_elf64_obj_info oi64;
128 /* MIPS sign extends its 32 bit addresses. We could conceivably use
129 extract_typed_address here, but to do so, we'd have to construct an
130 appropriate type. Calling extract_signed_integer seems simpler. */
133 extract_mips_address (void *addr, int len, enum bfd_endian byte_order)
135 return extract_signed_integer (addr, len, byte_order);
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. */
142 static struct lm_info
143 fetch_lm_info (CORE_ADDR addr)
145 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
147 union irix_obj_info buf;
151 /* The smallest region that we'll need is for buf.ol32. We'll read
152 that first. We'll read more of the buffer later if we have to deal
153 with one of the other cases. (We don't want to incur a memory error
154 if we were to read a larger region that generates an error due to
155 being at the end of a page or the like.) */
156 read_memory (addr, (char *) &buf, sizeof (buf.ol32));
158 if (extract_unsigned_integer (buf.magic.b, sizeof (buf.magic), byte_order)
161 /* Use buf.ol32... */
163 CORE_ADDR obj_addr = extract_mips_address (&buf.ol32.data,
164 sizeof (buf.ol32.data),
166 li.next = extract_mips_address (&buf.ol32.next,
167 sizeof (buf.ol32.next), byte_order);
169 read_memory (obj_addr, obj_buf, sizeof (obj_buf));
171 li.pathname_addr = extract_mips_address (&obj_buf[236], 4, byte_order);
172 li.pathname_len = 0; /* unknown */
173 li.reloc_offset = extract_mips_address (&obj_buf[196], 4, byte_order)
174 - extract_mips_address (&obj_buf[248], 4, byte_order);
177 else if (extract_unsigned_integer (buf.oi32.oi_size.b,
178 sizeof (buf.oi32.oi_size), byte_order)
179 == sizeof (buf.oi32))
181 /* Use buf.oi32... */
183 /* Read rest of buffer. */
184 read_memory (addr + sizeof (buf.ol32),
185 ((char *) &buf) + sizeof (buf.ol32),
186 sizeof (buf.oi32) - sizeof (buf.ol32));
188 /* Fill in fields using buffer contents. */
189 li.next = extract_mips_address (&buf.oi32.oi_next,
190 sizeof (buf.oi32.oi_next), byte_order);
191 li.reloc_offset = extract_mips_address (&buf.oi32.oi_ehdr,
192 sizeof (buf.oi32.oi_ehdr),
194 - extract_mips_address (&buf.oi32.oi_orig_ehdr,
195 sizeof (buf.oi32.oi_orig_ehdr), byte_order);
196 li.pathname_addr = extract_mips_address (&buf.oi32.oi_pathname,
197 sizeof (buf.oi32.oi_pathname),
199 li.pathname_len = extract_unsigned_integer (buf.oi32.oi_pathname_len.b,
204 else if (extract_unsigned_integer (buf.oi64.oi_size.b,
205 sizeof (buf.oi64.oi_size), byte_order)
206 == sizeof (buf.oi64))
208 /* Use buf.oi64... */
210 /* Read rest of buffer. */
211 read_memory (addr + sizeof (buf.ol32),
212 ((char *) &buf) + sizeof (buf.ol32),
213 sizeof (buf.oi64) - sizeof (buf.ol32));
215 /* Fill in fields using buffer contents. */
216 li.next = extract_mips_address (&buf.oi64.oi_next,
217 sizeof (buf.oi64.oi_next), byte_order);
218 li.reloc_offset = extract_mips_address (&buf.oi64.oi_ehdr,
219 sizeof (buf.oi64.oi_ehdr),
221 - extract_mips_address (&buf.oi64.oi_orig_ehdr,
222 sizeof (buf.oi64.oi_orig_ehdr), byte_order);
223 li.pathname_addr = extract_mips_address (&buf.oi64.oi_pathname,
224 sizeof (buf.oi64.oi_pathname),
226 li.pathname_len = extract_unsigned_integer (buf.oi64.oi_pathname_len.b,
233 error (_("Unable to fetch shared library obj_info or obj_list info."));
239 /* The symbol which starts off the list of shared libraries. */
240 #define DEBUG_BASE "__rld_obj_head"
242 static void *base_breakpoint;
244 static CORE_ADDR debug_base; /* Base of dynamic linker structures */
250 locate_base -- locate the base address of dynamic linker structs
254 CORE_ADDR locate_base (void)
258 For both the SunOS and SVR4 shared library implementations, if the
259 inferior executable has been linked dynamically, there is a single
260 address somewhere in the inferior's data space which is the key to
261 locating all of the dynamic linker's runtime structures. This
262 address is the value of the symbol defined by the macro DEBUG_BASE.
263 The job of this function is to find and return that address, or to
264 return 0 if there is no such address (the executable is statically
267 For SunOS, the job is almost trivial, since the dynamic linker and
268 all of it's structures are statically linked to the executable at
269 link time. Thus the symbol for the address we are looking for has
270 already been added to the minimal symbol table for the executable's
271 objfile at the time the symbol file's symbols were read, and all we
272 have to do is look it up there. Note that we explicitly do NOT want
273 to find the copies in the shared library.
275 The SVR4 version is much more complicated because the dynamic linker
276 and it's structures are located in the shared C library, which gets
277 run as the executable's "interpreter" by the kernel. We have to go
278 to a lot more work to discover the address of DEBUG_BASE. Because
279 of this complexity, we cache the value we find and return that value
280 on subsequent invocations. Note there is no copy in the executable
283 Irix 5 is basically like SunOS.
285 Note that we can assume nothing about the process state at the time
286 we need to find this address. We may be stopped on the first instruc-
287 tion of the interpreter (C shared library), the first instruction of
288 the executable itself, or somewhere else entirely (if we attached
289 to the process for example).
296 struct minimal_symbol *msymbol;
297 CORE_ADDR address = 0;
299 msymbol = lookup_minimal_symbol (DEBUG_BASE, NULL, symfile_objfile);
300 if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
302 address = SYMBOL_VALUE_ADDRESS (msymbol);
311 disable_break -- remove the "mapping changed" breakpoint
315 static int disable_break ()
319 Removes the breakpoint that gets hit when the dynamic linker
320 completes a mapping change.
330 /* Note that breakpoint address and original contents are in our address
331 space, so we just need to write the original contents back. */
333 if (deprecated_remove_raw_breakpoint (target_gdbarch, base_breakpoint) != 0)
338 base_breakpoint = NULL;
340 /* Note that it is possible that we have stopped at a location that
341 is different from the location where we inserted our breakpoint.
342 On mips-irix, we can actually land in __dbx_init(), so we should
343 not check the PC against our breakpoint address here. See procfs.c
353 enable_break -- arrange for dynamic linker to hit breakpoint
357 int enable_break (void)
361 This functions inserts a breakpoint at the entry point of the
362 main executable, where all shared libraries are mapped in.
368 if (symfile_objfile != NULL)
371 = deprecated_insert_raw_breakpoint (target_gdbarch,
372 entry_point_address ());
374 if (base_breakpoint != NULL)
385 irix_solib_create_inferior_hook -- shared library startup support
389 void solib_create_inferior_hook ()
393 When gdb starts up the inferior, it nurses it along (through the
394 shell) until it is ready to execute it's first instruction. At this
395 point, this function gets called via expansion of the macro
396 SOLIB_CREATE_INFERIOR_HOOK.
398 For SunOS executables, this first instruction is typically the
399 one at "_start", or a similar text label, regardless of whether
400 the executable is statically or dynamically linked. The runtime
401 startup code takes care of dynamically linking in any shared
402 libraries, once gdb allows the inferior to continue.
404 For SVR4 executables, this first instruction is either the first
405 instruction in the dynamic linker (for dynamically linked
406 executables) or the instruction at "start" for statically linked
407 executables. For dynamically linked executables, the system
408 first exec's /lib/libc.so.N, which contains the dynamic linker,
409 and starts it running. The dynamic linker maps in any needed
410 shared libraries, maps in the actual user executable, and then
411 jumps to "start" in the user executable.
413 For both SunOS shared libraries, and SVR4 shared libraries, we
414 can arrange to cooperate with the dynamic linker to discover the
415 names of shared libraries that are dynamically linked, and the
416 base addresses to which they are linked.
418 This function is responsible for discovering those names and
419 addresses, and saving sufficient information about them to allow
420 their symbols to be read at a later time.
424 Between enable_break() and disable_break(), this code does not
425 properly handle hitting breakpoints which the user might have
426 set in the startup code or in the dynamic linker itself. Proper
427 handling will probably have to wait until the implementation is
428 changed to use the "breakpoint handler function" method.
430 Also, what if child has exit()ed? Must exit loop somehow.
434 irix_solib_create_inferior_hook (void)
436 struct inferior *inf;
437 struct thread_info *tp;
439 if (!enable_break ())
441 warning (_("shared library handler failed to enable breakpoint"));
445 /* Now run the target. It will eventually hit the breakpoint, at
446 which point all of the libraries will have been mapped in and we
447 can go groveling around in the dynamic linker structures to find
448 out what we need to know about them. */
450 inf = current_inferior ();
451 tp = inferior_thread ();
453 clear_proceed_status ();
455 inf->stop_soon = STOP_QUIETLY;
456 tp->stop_signal = TARGET_SIGNAL_0;
460 target_resume (pid_to_ptid (-1), 0, tp->stop_signal);
461 wait_for_inferior (0);
463 while (tp->stop_signal != TARGET_SIGNAL_TRAP);
465 /* We are now either at the "mapping complete" breakpoint (or somewhere
466 else, a condition we aren't prepared to deal with anyway), so adjust
467 the PC as necessary after a breakpoint, disable the breakpoint, and
468 add any shared libraries that were mapped in. */
470 if (!disable_break ())
472 warning (_("shared library handler failed to disable breakpoint"));
475 /* solib_add will call reinit_frame_cache.
476 But we are stopped in the startup code and we might not have symbols
477 for the startup code, so heuristic_proc_start could be called
478 and will put out an annoying warning.
479 Delaying the resetting of stop_soon until after symbol loading
480 suppresses the warning. */
481 solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
482 inf->stop_soon = NO_STOP_QUIETLY;
487 current_sos -- build a list of currently loaded shared objects
491 struct so_list *current_sos ()
495 Build a list of `struct so_list' objects describing the shared
496 objects currently loaded in the inferior. This list does not
497 include an entry for the main executable file.
499 Note that we only gather information directly available from the
500 inferior --- we don't examine any of the shared library files
501 themselves. The declaration of `struct so_list' says which fields
502 we provide values for. */
504 static struct so_list *
505 irix_current_sos (void)
507 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
508 int addr_size = gdbarch_addr_bit (target_gdbarch) / TARGET_CHAR_BIT;
511 struct so_list *head = 0;
512 struct so_list **link_ptr = &head;
516 /* Make sure we've looked up the inferior's dynamic linker's base
520 debug_base = locate_base ();
522 /* If we can't find the dynamic linker's base structure, this
523 must not be a dynamically linked executable. Hmm. */
528 read_memory (debug_base, addr_buf, addr_size);
529 lma = extract_mips_address (addr_buf, addr_size, byte_order);
533 lm = fetch_lm_info (lma);
540 = (struct so_list *) xmalloc (sizeof (struct so_list));
541 struct cleanup *old_chain = make_cleanup (xfree, new);
543 memset (new, 0, sizeof (*new));
545 new->lm_info = xmalloc (sizeof (struct lm_info));
546 make_cleanup (xfree, new->lm_info);
550 /* Extract this shared object's name. */
551 name_size = lm.pathname_len;
553 name_size = SO_NAME_MAX_PATH_SIZE - 1;
555 if (name_size >= SO_NAME_MAX_PATH_SIZE)
557 name_size = SO_NAME_MAX_PATH_SIZE - 1;
559 ("current_sos: truncating name of %d characters to only %d characters",
560 lm.pathname_len, name_size);
563 target_read_string (lm.pathname_addr, &name_buf,
564 name_size, &errcode);
566 warning (_("Can't read pathname for load map: %s."),
567 safe_strerror (errcode));
570 strncpy (new->so_name, name_buf, name_size);
571 new->so_name[name_size] = '\0';
573 strcpy (new->so_original_name, new->so_name);
578 link_ptr = &new->next;
580 discard_cleanups (old_chain);
593 irix_open_symbol_file_object
597 void irix_open_symbol_file_object (void *from_tty)
601 If no open symbol file, attempt to locate and open the main symbol
602 file. On IRIX, this is the first link map entry. If its name is
603 here, we can open it. Useful when attaching to a process without
604 first loading its symbol file.
606 If FROM_TTYP dereferences to a non-zero integer, allow messages to
607 be printed. This parameter is a pointer rather than an int because
608 open_symbol_file_object() is called via catch_errors() and
609 catch_errors() requires a pointer argument. */
612 irix_open_symbol_file_object (void *from_ttyp)
614 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
615 int addr_size = gdbarch_addr_bit (target_gdbarch) / TARGET_CHAR_BIT;
619 struct cleanup *cleanups;
621 int from_tty = *(int *) from_ttyp;
625 if (!query (_("Attempt to reload symbols from process? ")))
628 if ((debug_base = locate_base ()) == 0)
629 return 0; /* failed somehow... */
631 /* First link map member should be the executable. */
632 read_memory (debug_base, addr_buf, addr_size);
633 lma = extract_mips_address (addr_buf, addr_size, byte_order);
635 return 0; /* failed somehow... */
637 lm = fetch_lm_info (lma);
639 if (lm.pathname_addr == 0)
640 return 0; /* No filename. */
642 /* Now fetch the filename from target memory. */
643 target_read_string (lm.pathname_addr, &filename, SO_NAME_MAX_PATH_SIZE - 1,
648 warning (_("failed to read exec filename from attached file: %s"),
649 safe_strerror (errcode));
653 cleanups = make_cleanup (xfree, filename);
654 /* Have a pathname: read the symbol file. */
655 symbol_file_add_main (filename, from_tty);
657 do_cleanups (cleanups);
667 irix_special_symbol_handling -- additional shared library symbol handling
671 void irix_special_symbol_handling ()
675 Once the symbols from a shared object have been loaded in the usual
676 way, we are called to do any system specific symbol handling that
679 For SunOS4, this consisted of grunging around in the dynamic
680 linkers structures to find symbol definitions for "common" symbols
681 and adding them to the minimal symbol table for the runtime common
684 However, for IRIX, there's nothing to do.
689 irix_special_symbol_handling (void)
693 /* Using the solist entry SO, relocate the addresses in SEC. */
696 irix_relocate_section_addresses (struct so_list *so,
697 struct target_section *sec)
699 sec->addr += so->lm_info->reloc_offset;
700 sec->endaddr += so->lm_info->reloc_offset;
703 /* Free the lm_info struct. */
706 irix_free_so (struct so_list *so)
711 /* Clear backend specific state. */
714 irix_clear_solib (void)
719 /* Return 1 if PC lies in the dynamic symbol resolution code of the
722 irix_in_dynsym_resolve_code (CORE_ADDR pc)
727 struct target_so_ops irix_so_ops;
729 /* Provide a prototype to silence -Wmissing-prototypes. */
730 extern initialize_file_ftype _initialize_irix_solib;
733 _initialize_irix_solib (void)
735 irix_so_ops.relocate_section_addresses = irix_relocate_section_addresses;
736 irix_so_ops.free_so = irix_free_so;
737 irix_so_ops.clear_solib = irix_clear_solib;
738 irix_so_ops.solib_create_inferior_hook = irix_solib_create_inferior_hook;
739 irix_so_ops.special_symbol_handling = irix_special_symbol_handling;
740 irix_so_ops.current_sos = irix_current_sos;
741 irix_so_ops.open_symbol_file_object = irix_open_symbol_file_object;
742 irix_so_ops.in_dynsym_resolve_code = irix_in_dynsym_resolve_code;
743 irix_so_ops.bfd_open = solib_bfd_open;