* utils.c (make_cleanup_bfd_unref): Rename from
[deliverable/binutils-gdb.git] / gdb / symfile-mem.c
CommitLineData
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1/* Reading symbol files from memory.
2
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3 Copyright (C) 1986-1987, 1989, 1991, 1994-1996, 1998, 2000-2005,
4 2007-2012 Free Software Foundation, Inc.
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5
6 This file is part of GDB.
7
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
a9762ec7 10 the Free Software Foundation; either version 3 of the License, or
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11 (at your option) any later version.
12
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.
17
18 You should have received a copy of the GNU General Public License
a9762ec7 19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
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20
21/* This file defines functions (and commands to exercise those
22 functions) for reading debugging information from object files
23 whose images are mapped directly into the inferior's memory. For
24 example, the Linux kernel maps a "syscall DSO" into each process's
25 address space; this DSO provides kernel-specific code for some
26 system calls.
27
28 At the moment, BFD only has functions for parsing object files from
29 memory for the ELF format, even though the general idea isn't
30 ELF-specific. This means that BFD only provides the functions GDB
31 needs when configured for ELF-based targets. So these functions
32 may only be compiled on ELF-based targets.
33
34 GDB has no idea whether it has been configured for an ELF-based
35 target or not: it just tries to handle whatever files it is given.
36 But this means there are no preprocessor symbols on which we could
37 make these functions' compilation conditional.
38
39 So, for the time being, we put these functions alone in this file,
40 and have .mt files reference them as appropriate. In the future, I
41 hope BFD will provide a format-independent bfd_from_remote_memory
42 entry point. */
43
44
45#include "defs.h"
46#include "symtab.h"
47#include "gdbcore.h"
48#include "objfiles.h"
60250e8b 49#include "exceptions.h"
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50#include "gdbcmd.h"
51#include "target.h"
52#include "value.h"
53#include "symfile.h"
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54#include "observer.h"
55#include "auxv.h"
56#include "elf/common.h"
cbb099e8 57#include "gdb_bfd.h"
eb4556d7 58
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59/* Verify parameters of target_read_memory_bfd and target_read_memory are
60 compatible. */
61
62gdb_static_assert (sizeof (CORE_ADDR) == sizeof (bfd_vma));
63gdb_static_assert (sizeof (gdb_byte) == sizeof (bfd_byte));
1b162304 64gdb_static_assert (sizeof (ssize_t) <= sizeof (bfd_size_type));
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65
66/* Provide bfd/ compatible prototype for target_read_memory. Casting would not
67 be enough as LEN width may differ. */
68
69static int
70target_read_memory_bfd (bfd_vma memaddr, bfd_byte *myaddr, bfd_size_type len)
71{
72 /* MYADDR must be already allocated for the LEN size so it has to fit in
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73 ssize_t. */
74 gdb_assert ((ssize_t) len == len);
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75
76 return target_read_memory (memaddr, myaddr, len);
77}
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78
79/* Read inferior memory at ADDR to find the header of a loaded object file
80 and read its in-core symbols out of inferior memory. TEMPL is a bfd
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81 representing the target's format. NAME is the name to use for this
82 symbol file in messages; it can be NULL or a malloc-allocated string
83 which will be attached to the BFD. */
97c34f65 84static struct objfile *
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85symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr, char *name,
86 int from_tty)
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87{
88 struct objfile *objf;
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89 struct bfd *nbfd;
90 struct bfd_section *sec;
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91 bfd_vma loadbase;
92 struct section_addr_info *sai;
93 unsigned int i;
3bb47e8b 94 struct cleanup *cleanup;
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95
96 if (bfd_get_flavour (templ) != bfd_target_elf_flavour)
8a3fe4f8 97 error (_("add-symbol-file-from-memory not supported for this target"));
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98
99 nbfd = bfd_elf_bfd_from_remote_memory (templ, addr, &loadbase,
fe78531d 100 target_read_memory_bfd);
eb4556d7 101 if (nbfd == NULL)
8a3fe4f8 102 error (_("Failed to read a valid object file image from memory."));
eb4556d7 103
cbb099e8 104 gdb_bfd_ref (nbfd);
12b8a2cb 105 if (name == NULL)
a4453b7e 106 nbfd->filename = "shared object read from target memory";
12b8a2cb 107 else
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108 {
109 nbfd->filename = name;
110 gdb_bfd_stash_filename (nbfd);
111 xfree (name);
112 }
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113
114 if (!bfd_check_format (nbfd, bfd_object))
115 {
f9a062ff 116 make_cleanup_bfd_unref (nbfd);
8a3fe4f8 117 error (_("Got object file from memory but can't read symbols: %s."),
eb4556d7 118 bfd_errmsg (bfd_get_error ()));
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119 }
120
121 sai = alloc_section_addr_info (bfd_count_sections (nbfd));
3bb47e8b 122 cleanup = make_cleanup (xfree, sai);
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123 i = 0;
124 for (sec = nbfd->sections; sec != NULL; sec = sec->next)
125 if ((bfd_get_section_flags (nbfd, sec) & (SEC_ALLOC|SEC_LOAD)) != 0)
126 {
127 sai->other[i].addr = bfd_get_section_vma (nbfd, sec) + loadbase;
128 sai->other[i].name = (char *) bfd_get_section_name (nbfd, sec);
129 sai->other[i].sectindex = sec->index;
130 ++i;
131 }
132
7eedccfa 133 objf = symbol_file_add_from_bfd (nbfd, from_tty ? SYMFILE_VERBOSE : 0,
63524580 134 sai, OBJF_SHARED, NULL);
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135
136 /* This might change our ideas about frames already looked at. */
137 reinit_frame_cache ();
138
3bb47e8b 139 do_cleanups (cleanup);
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140 return objf;
141}
142
143
144static void
145add_symbol_file_from_memory_command (char *args, int from_tty)
146{
147 CORE_ADDR addr;
97c34f65 148 struct bfd *templ;
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149
150 if (args == NULL)
8a3fe4f8 151 error (_("add-symbol-file-from-memory requires an expression argument"));
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152
153 addr = parse_and_eval_address (args);
154
155 /* We need some representative bfd to know the target we are looking at. */
156 if (symfile_objfile != NULL)
157 templ = symfile_objfile->obfd;
158 else
159 templ = exec_bfd;
160 if (templ == NULL)
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161 error (_("Must use symbol-file or exec-file "
162 "before add-symbol-file-from-memory."));
eb4556d7 163
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164 symbol_file_add_from_memory (templ, addr, NULL, from_tty);
165}
166
167/* Arguments for symbol_file_add_from_memory_wrapper. */
168
169struct symbol_file_add_from_memory_args
170{
171 struct bfd *bfd;
172 CORE_ADDR sysinfo_ehdr;
173 char *name;
174 int from_tty;
175};
176
177/* Wrapper function for symbol_file_add_from_memory, for
178 catch_exceptions. */
179
180static int
181symbol_file_add_from_memory_wrapper (struct ui_out *uiout, void *data)
182{
183 struct symbol_file_add_from_memory_args *args = data;
184
185 symbol_file_add_from_memory (args->bfd, args->sysinfo_ehdr, args->name,
186 args->from_tty);
187 return 0;
188}
189
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190/* Try to add the symbols for the vsyscall page, if there is one.
191 This function is called via the inferior_created observer. */
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192
193static void
194add_vsyscall_page (struct target_ops *target, int from_tty)
195{
196 CORE_ADDR sysinfo_ehdr;
197
198 if (target_auxv_search (target, AT_SYSINFO_EHDR, &sysinfo_ehdr) > 0
199 && sysinfo_ehdr != (CORE_ADDR) 0)
200 {
201 struct bfd *bfd;
202 struct symbol_file_add_from_memory_args args;
203
204 if (core_bfd != NULL)
205 bfd = core_bfd;
206 else if (exec_bfd != NULL)
207 bfd = exec_bfd;
208 else
209 /* FIXME: cagney/2004-05-06: Should not require an existing
210 BFD when trying to create a run-time BFD of the VSYSCALL
211 page in the inferior. Unfortunately that's the current
212 interface so for the moment bail. Introducing a
213 ``bfd_runtime'' (a BFD created using the loaded image) file
214 format should fix this. */
215 {
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216 warning (_("Could not load vsyscall page "
217 "because no executable was specified\n"
218 "try using the \"file\" command first."));
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219 return;
220 }
221 args.bfd = bfd;
222 args.sysinfo_ehdr = sysinfo_ehdr;
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223 args.name = xstrprintf ("system-supplied DSO at %s",
224 paddress (target_gdbarch, sysinfo_ehdr));
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225 /* Pass zero for FROM_TTY, because the action of loading the
226 vsyscall DSO was not triggered by the user, even if the user
227 typed "run" at the TTY. */
228 args.from_tty = 0;
79a45e25 229 catch_exceptions (current_uiout, symbol_file_add_from_memory_wrapper,
1c3c7ee7 230 &args, RETURN_MASK_ALL);
12b8a2cb 231 }
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232}
233
234\f
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235
236/* Provide a prototype to silence -Wmissing-prototypes. */
237extern initialize_file_ftype _initialize_symfile_mem;
238
eb4556d7 239void
da745b36 240_initialize_symfile_mem (void)
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241{
242 add_cmd ("add-symbol-file-from-memory", class_files,
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243 add_symbol_file_from_memory_command,
244 _("Load the symbols out of memory from a "
245 "dynamically loaded object file.\n"
246 "Give an expression for the address "
247 "of the file's shared object file header."),
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248 &cmdlist);
249
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250 /* Want to know of each new inferior so that its vsyscall info can
251 be extracted. */
252 observer_attach_inferior_created (add_vsyscall_page);
eb4556d7 253}
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