Commit | Line | Data |
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eb4556d7 JB |
1 | /* Reading symbol files from memory. |
2 | ||
3 | Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, | |
4 | 2001, 2002, 2003, 2004 Free Software Foundation, Inc. | |
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 | |
10 | the Free Software Foundation; either version 2 of the License, or | |
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 | |
19 | along with this program; if not, write to the Free Software | |
20 | Foundation, Inc., 59 Temple Place - Suite 330, | |
21 | Boston, MA 02111-1307, USA. */ | |
22 | ||
23 | /* This file defines functions (and commands to exercise those | |
24 | functions) for reading debugging information from object files | |
25 | whose images are mapped directly into the inferior's memory. For | |
26 | example, the Linux kernel maps a "syscall DSO" into each process's | |
27 | address space; this DSO provides kernel-specific code for some | |
28 | system calls. | |
29 | ||
30 | At the moment, BFD only has functions for parsing object files from | |
31 | memory for the ELF format, even though the general idea isn't | |
32 | ELF-specific. This means that BFD only provides the functions GDB | |
33 | needs when configured for ELF-based targets. So these functions | |
34 | may only be compiled on ELF-based targets. | |
35 | ||
36 | GDB has no idea whether it has been configured for an ELF-based | |
37 | target or not: it just tries to handle whatever files it is given. | |
38 | But this means there are no preprocessor symbols on which we could | |
39 | make these functions' compilation conditional. | |
40 | ||
41 | So, for the time being, we put these functions alone in this file, | |
42 | and have .mt files reference them as appropriate. In the future, I | |
43 | hope BFD will provide a format-independent bfd_from_remote_memory | |
44 | entry point. */ | |
45 | ||
46 | ||
47 | #include "defs.h" | |
48 | #include "symtab.h" | |
49 | #include "gdbcore.h" | |
50 | #include "objfiles.h" | |
60250e8b | 51 | #include "exceptions.h" |
eb4556d7 JB |
52 | #include "gdbcmd.h" |
53 | #include "target.h" | |
54 | #include "value.h" | |
55 | #include "symfile.h" | |
12b8a2cb DJ |
56 | #include "observer.h" |
57 | #include "auxv.h" | |
58 | #include "elf/common.h" | |
eb4556d7 JB |
59 | |
60 | ||
10e2d419 AC |
61 | /* FIXME: cagney/2005-01-27: Should be a function with the signature: |
62 | int (void *object, const bfd_byte *myaddr, int len). */ | |
63 | ||
64 | static int | |
65 | do_target_read_memory (bfd_vma vma, char *myaddr, int len) | |
66 | { | |
67 | return target_read_memory (vma, myaddr, len); | |
68 | } | |
69 | ||
eb4556d7 JB |
70 | /* Read inferior memory at ADDR to find the header of a loaded object file |
71 | and read its in-core symbols out of inferior memory. TEMPL is a bfd | |
12b8a2cb DJ |
72 | representing the target's format. NAME is the name to use for this |
73 | symbol file in messages; it can be NULL or a malloc-allocated string | |
74 | which will be attached to the BFD. */ | |
97c34f65 | 75 | static struct objfile * |
12b8a2cb DJ |
76 | symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr, char *name, |
77 | int from_tty) | |
eb4556d7 JB |
78 | { |
79 | struct objfile *objf; | |
97c34f65 AC |
80 | struct bfd *nbfd; |
81 | struct bfd_section *sec; | |
eb4556d7 JB |
82 | bfd_vma loadbase; |
83 | struct section_addr_info *sai; | |
84 | unsigned int i; | |
85 | ||
86 | if (bfd_get_flavour (templ) != bfd_target_elf_flavour) | |
87 | error ("add-symbol-file-from-memory not supported for this target"); | |
88 | ||
89 | nbfd = bfd_elf_bfd_from_remote_memory (templ, addr, &loadbase, | |
10e2d419 | 90 | do_target_read_memory); |
eb4556d7 | 91 | if (nbfd == NULL) |
97c34f65 | 92 | error ("Failed to read a valid object file image from memory."); |
eb4556d7 | 93 | |
12b8a2cb DJ |
94 | if (name == NULL) |
95 | nbfd->filename = xstrdup ("shared object read from target memory"); | |
96 | else | |
97 | nbfd->filename = name; | |
eb4556d7 JB |
98 | |
99 | if (!bfd_check_format (nbfd, bfd_object)) | |
100 | { | |
101 | /* FIXME: should be checking for errors from bfd_close (for one thing, | |
102 | on error it does not free all the storage associated with the | |
103 | bfd). */ | |
104 | bfd_close (nbfd); | |
105 | error ("Got object file from memory but can't read symbols: %s.", | |
106 | bfd_errmsg (bfd_get_error ())); | |
eb4556d7 JB |
107 | } |
108 | ||
109 | sai = alloc_section_addr_info (bfd_count_sections (nbfd)); | |
110 | make_cleanup (xfree, sai); | |
111 | i = 0; | |
112 | for (sec = nbfd->sections; sec != NULL; sec = sec->next) | |
113 | if ((bfd_get_section_flags (nbfd, sec) & (SEC_ALLOC|SEC_LOAD)) != 0) | |
114 | { | |
115 | sai->other[i].addr = bfd_get_section_vma (nbfd, sec) + loadbase; | |
116 | sai->other[i].name = (char *) bfd_get_section_name (nbfd, sec); | |
117 | sai->other[i].sectindex = sec->index; | |
118 | ++i; | |
119 | } | |
120 | ||
121 | objf = symbol_file_add_from_bfd (nbfd, from_tty, | |
122 | sai, 0, OBJF_SHARED); | |
123 | ||
124 | /* This might change our ideas about frames already looked at. */ | |
125 | reinit_frame_cache (); | |
126 | ||
127 | return objf; | |
128 | } | |
129 | ||
130 | ||
131 | static void | |
132 | add_symbol_file_from_memory_command (char *args, int from_tty) | |
133 | { | |
134 | CORE_ADDR addr; | |
97c34f65 | 135 | struct bfd *templ; |
eb4556d7 JB |
136 | |
137 | if (args == NULL) | |
138 | error ("add-symbol-file-from-memory requires an expression argument"); | |
139 | ||
140 | addr = parse_and_eval_address (args); | |
141 | ||
142 | /* We need some representative bfd to know the target we are looking at. */ | |
143 | if (symfile_objfile != NULL) | |
144 | templ = symfile_objfile->obfd; | |
145 | else | |
146 | templ = exec_bfd; | |
147 | if (templ == NULL) | |
148 | error ("\ | |
149 | Must use symbol-file or exec-file before add-symbol-file-from-memory."); | |
150 | ||
12b8a2cb DJ |
151 | symbol_file_add_from_memory (templ, addr, NULL, from_tty); |
152 | } | |
153 | ||
154 | /* Arguments for symbol_file_add_from_memory_wrapper. */ | |
155 | ||
156 | struct symbol_file_add_from_memory_args | |
157 | { | |
158 | struct bfd *bfd; | |
159 | CORE_ADDR sysinfo_ehdr; | |
160 | char *name; | |
161 | int from_tty; | |
162 | }; | |
163 | ||
164 | /* Wrapper function for symbol_file_add_from_memory, for | |
165 | catch_exceptions. */ | |
166 | ||
167 | static int | |
168 | symbol_file_add_from_memory_wrapper (struct ui_out *uiout, void *data) | |
169 | { | |
170 | struct symbol_file_add_from_memory_args *args = data; | |
171 | ||
172 | symbol_file_add_from_memory (args->bfd, args->sysinfo_ehdr, args->name, | |
173 | args->from_tty); | |
174 | return 0; | |
175 | } | |
176 | ||
177 | /* Try to add the symbols for the vsyscall page, if there is one. This function | |
178 | is called via the inferior_created observer. */ | |
179 | ||
180 | static void | |
181 | add_vsyscall_page (struct target_ops *target, int from_tty) | |
182 | { | |
183 | CORE_ADDR sysinfo_ehdr; | |
184 | ||
185 | if (target_auxv_search (target, AT_SYSINFO_EHDR, &sysinfo_ehdr) > 0 | |
186 | && sysinfo_ehdr != (CORE_ADDR) 0) | |
187 | { | |
188 | struct bfd *bfd; | |
189 | struct symbol_file_add_from_memory_args args; | |
190 | ||
191 | if (core_bfd != NULL) | |
192 | bfd = core_bfd; | |
193 | else if (exec_bfd != NULL) | |
194 | bfd = exec_bfd; | |
195 | else | |
196 | /* FIXME: cagney/2004-05-06: Should not require an existing | |
197 | BFD when trying to create a run-time BFD of the VSYSCALL | |
198 | page in the inferior. Unfortunately that's the current | |
199 | interface so for the moment bail. Introducing a | |
200 | ``bfd_runtime'' (a BFD created using the loaded image) file | |
201 | format should fix this. */ | |
202 | { | |
203 | warning ("could not load vsyscall page because no executable was specified"); | |
204 | warning ("try using the \"file\" command first"); | |
205 | return; | |
206 | } | |
207 | args.bfd = bfd; | |
208 | args.sysinfo_ehdr = sysinfo_ehdr; | |
209 | xasprintf (&args.name, "system-supplied DSO at 0x%s", | |
210 | paddr_nz (sysinfo_ehdr)); | |
211 | /* Pass zero for FROM_TTY, because the action of loading the | |
212 | vsyscall DSO was not triggered by the user, even if the user | |
213 | typed "run" at the TTY. */ | |
214 | args.from_tty = 0; | |
215 | catch_exceptions (uiout, symbol_file_add_from_memory_wrapper, | |
1c3c7ee7 | 216 | &args, RETURN_MASK_ALL); |
12b8a2cb | 217 | } |
eb4556d7 JB |
218 | } |
219 | ||
220 | \f | |
221 | void | |
da745b36 | 222 | _initialize_symfile_mem (void) |
eb4556d7 JB |
223 | { |
224 | add_cmd ("add-symbol-file-from-memory", class_files, | |
225 | add_symbol_file_from_memory_command, | |
226 | "\ | |
227 | Load the symbols out of memory from a dynamically loaded object file.\n\ | |
228 | Give an expression for the address of the file's shared object file header.", | |
229 | &cmdlist); | |
230 | ||
12b8a2cb DJ |
231 | /* Want to know of each new inferior so that its vsyscall info can |
232 | be extracted. */ | |
233 | observer_attach_inferior_created (add_vsyscall_page); | |
eb4556d7 | 234 | } |