1 /* Program and address space management, for GDB, the GNU debugger.
3 Copyright (C) 2009 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
33 struct program_space_data;
35 /* A program space represents a symbolic view of an address space.
36 Roughly speaking, it holds all the data associated with a
37 non-running-yet program (main executable, main symbols), and when
38 an inferior is running and is bound to it, includes the list of its
39 mapped in shared libraries.
41 In the traditional debugging scenario, there's a 1-1 correspondence
42 among program spaces, inferiors and address spaces, like so:
44 pspace1 (prog1) <--> inf1(pid1) <--> aspace1
46 In the case of debugging more than one traditional unix process or
47 program, we still have:
49 |-----------------+------------+---------|
50 | pspace1 (prog1) | inf1(pid1) | aspace1 |
51 |----------------------------------------|
52 | pspace2 (prog1) | no inf yet | aspace2 |
53 |-----------------+------------+---------|
54 | pspace3 (prog2) | inf2(pid2) | aspace3 |
55 |-----------------+------------+---------|
57 In the former example, if inf1 forks (and GDB stays attached to
58 both processes), the new child will have its own program and
59 address spaces. Like so:
61 |-----------------+------------+---------|
62 | pspace1 (prog1) | inf1(pid1) | aspace1 |
63 |-----------------+------------+---------|
64 | pspace2 (prog1) | inf2(pid2) | aspace2 |
65 |-----------------+------------+---------|
67 However, had inf1 from the latter case vforked instead, it would
68 share the program and address spaces with its parent, until it
69 execs or exits, like so:
71 |-----------------+------------+---------|
72 | pspace1 (prog1) | inf1(pid1) | aspace1 |
74 |-----------------+------------+---------|
76 When the vfork child execs, it is finally given new program and
79 |-----------------+------------+---------|
80 | pspace1 (prog1) | inf1(pid1) | aspace1 |
81 |-----------------+------------+---------|
82 | pspace2 (prog1) | inf2(pid2) | aspace2 |
83 |-----------------+------------+---------|
85 There are targets where the OS (if any) doesn't provide memory
86 management or VM protection, where all inferiors share the same
87 address space --- e.g. uClinux. GDB models this by having all
88 inferiors share the same address space, but, giving each its own
89 program space, like so:
91 |-----------------+------------+---------|
92 | pspace1 (prog1) | inf1(pid1) | |
93 |-----------------+------------+ |
94 | pspace2 (prog1) | inf2(pid2) | aspace1 |
95 |-----------------+------------+ |
96 | pspace3 (prog2) | inf3(pid3) | |
97 |-----------------+------------+---------|
99 The address space sharing matters for run control and breakpoints
100 management. E.g., did we just hit a known breakpoint that we need
101 to step over? Is this breakpoint a duplicate of this other one, or
102 do I need to insert a trap?
104 Then, there are targets where all symbols look the same for all
105 inferiors, although each has its own address space, as e.g.,
106 Ericsson DICOS. In such case, the model is:
108 |---------+------------+---------|
109 | | inf1(pid1) | aspace1 |
110 | +------------+---------|
111 | pspace | inf2(pid2) | aspace2 |
112 | +------------+---------|
113 | | inf3(pid3) | aspace3 |
114 |---------+------------+---------|
116 Note however, that the DICOS debug API takes care of making GDB
117 believe that breakpoints are "global". That is, although each
118 process does have its own private copy of data symbols (just like a
119 bunch of forks), to the breakpoints module, all processes share a
120 single address space, so all breakpoints set at the same address
121 are duplicates of each other, even breakpoints set in the data
122 space (e.g., call dummy breakpoints placed on stack). This allows
123 a simplification in the spaces implementation: we avoid caring for
124 a many-many links between address and program spaces. Either
125 there's a single address space bound to the program space
126 (traditional unix/uClinux), or, in the DICOS case, the address
127 space bound to the program space is mostly ignored. */
129 /* The program space structure. */
133 /* Pointer to next in linked list. */
134 struct program_space *next;
136 /* Unique ID number. */
139 /* The main executable loaded into this program space. This is
140 managed by the exec target. */
142 /* The BFD handle for the main executable. */
144 /* The last-modified time, from when the exec was brought in. */
147 /* The address space attached to this program space. More than one
148 program space may be bound to the same address space. In the
149 traditional unix-like debugging scenario, this will usually
150 match the address space bound to the inferior, and is mostly
151 used by the breakpoints module for address matches. If the
152 target shares a program space for all inferiors and breakpoints
153 are global, then this field is ignored (we don't currently
154 support inferiors sharing a program space if the target doesn't
155 make breakpoints global). */
156 struct address_space *aspace;
158 /* True if this program space's section offsets don't yet represent
159 the final offsets of the "live" address space (that is, the
160 section addresses still require the relocation offsets to be
161 applied, and hence we can't trust the section addresses for
162 anything that pokes at live memory). E.g., for qOffsets
163 targets, or for PIE executables, until we connect and ask the
164 target for the final relocation offsets, the symbols we've used
165 to set breakpoints point at the wrong addresses. */
166 int executing_startup;
168 /* True if no breakpoints should be inserted in this program
170 int breakpoints_not_allowed;
172 /* The object file that the main symbol table was loaded from
173 (e.g. the argument to the "symbol-file" or "file" command). */
174 struct objfile *symfile_object_file;
176 /* All known objfiles are kept in a linked list. This points to
177 the head of this list. */
178 struct objfile *objfiles;
180 /* The set of target sections matching the sections mapped into
181 this program space. Managed by both exec_ops and solib.c. */
182 struct target_section_table target_sections;
184 /* List of shared objects mapped into this space. Managed by
186 struct so_list *so_list;
188 /* Per pspace data-pointers required by other GDB modules. */
193 /* The object file that the main symbol table was loaded from (e.g. the
194 argument to the "symbol-file" or "file" command). */
196 #define symfile_objfile current_program_space->symfile_object_file
198 /* All known objfiles are kept in a linked list. This points to the
199 root of this list. */
200 #define object_files current_program_space->objfiles
202 /* The set of target sections matching the sections mapped into the
203 current program space. */
204 #define current_target_sections (¤t_program_space->target_sections)
206 /* The list of all program spaces. There's always at least one. */
207 extern struct program_space *program_spaces;
209 /* The current program space. This is always non-null. */
210 extern struct program_space *current_program_space;
212 #define ALL_PSPACES(pspace) \
213 for ((pspace) = program_spaces; (pspace) != NULL; (pspace) = (pspace)->next)
215 /* Add a new empty program space, and assign ASPACE to it. Returns the
216 pointer to the new object. */
217 extern struct program_space *add_program_space (struct address_space *aspace);
219 /* Release PSPACE and removes it from the pspace list. */
220 extern void remove_program_space (struct program_space *pspace);
222 /* Returns the number of program spaces listed. */
223 extern int number_of_program_spaces (void);
225 /* Copies program space SRC to DEST. Copies the main executable file,
226 and the main symbol file. Returns DEST. */
227 extern struct program_space *clone_program_space (struct program_space *dest,
228 struct program_space *src);
230 /* Save the current program space so that it may be restored by a later
231 call to do_cleanups. Returns the struct cleanup pointer needed for
232 later doing the cleanup. */
233 extern struct cleanup *save_current_program_space (void);
235 /* Sets PSPACE as the current program space. This is usually used
236 instead of set_current_space_and_thread when the current
237 thread/inferior is not important for the operations that follow.
238 E.g., when accessing the raw symbol tables. If memory access is
239 required, then you should use switch_to_program_space_and_thread.
240 Otherwise, it is the caller's responsibility to make sure that the
241 currently selected inferior/thread matches the selected program
243 extern void set_current_program_space (struct program_space *pspace);
245 /* Saves the current thread (may be null), frame and program space in
246 the current cleanup chain. */
247 extern struct cleanup *save_current_space_and_thread (void);
249 /* Switches full context to program space PSPACE. Switches to the
250 first thread found bound to PSPACE. */
251 extern void switch_to_program_space_and_thread (struct program_space *pspace);
253 /* Create a new address space object, and add it to the list. */
254 extern struct address_space *new_address_space (void);
256 /* Maybe create a new address space object, and add it to the list, or
257 return a pointer to an existing address space, in case inferiors
258 share an address space. */
259 extern struct address_space *maybe_new_address_space (void);
261 /* Returns the integer address space id of ASPACE. */
262 extern int address_space_num (struct address_space *aspace);
264 /* Update all program spaces matching to address spaces. The user may
265 have created several program spaces, and loaded executables into
266 them before connecting to the target interface that will create the
267 inferiors. All that happens before GDB has a chance to know if the
268 inferiors will share an address space or not. Call this after
269 having connected to the target interface and having fetched the
270 target description, to fixup the program/address spaces
272 extern void update_address_spaces (void);
274 /* Prune away automatically added program spaces that aren't required
276 extern void prune_program_spaces (void);
278 /* Keep a registry of per-pspace data-pointers required by other GDB
281 extern const struct program_space_data *register_program_space_data (void);
282 extern const struct program_space_data *register_program_space_data_with_cleanup
283 (void (*cleanup) (struct program_space *, void *));
284 extern void clear_program_space_data (struct program_space *pspace);
285 extern void set_program_space_data (struct program_space *pspace,
286 const struct program_space_data *data, void *value);
287 extern void *program_space_data (struct program_space *pspace,
288 const struct program_space_data *data);