1 /* Program and address space management, for GDB, the GNU debugger.
3 Copyright (C) 2009-2019 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/>. */
26 #include "gdbsupport/gdb_vecs.h"
28 #include "gdbsupport/next-iterator.h"
29 #include "gdbsupport/safe-iterator.h"
37 struct program_space_data
;
38 struct address_space_data
;
40 /* A program space represents a symbolic view of an address space.
41 Roughly speaking, it holds all the data associated with a
42 non-running-yet program (main executable, main symbols), and when
43 an inferior is running and is bound to it, includes the list of its
44 mapped in shared libraries.
46 In the traditional debugging scenario, there's a 1-1 correspondence
47 among program spaces, inferiors and address spaces, like so:
49 pspace1 (prog1) <--> inf1(pid1) <--> aspace1
51 In the case of debugging more than one traditional unix process or
52 program, we still have:
54 |-----------------+------------+---------|
55 | pspace1 (prog1) | inf1(pid1) | aspace1 |
56 |----------------------------------------|
57 | pspace2 (prog1) | no inf yet | aspace2 |
58 |-----------------+------------+---------|
59 | pspace3 (prog2) | inf2(pid2) | aspace3 |
60 |-----------------+------------+---------|
62 In the former example, if inf1 forks (and GDB stays attached to
63 both processes), the new child will have its own program and
64 address spaces. Like so:
66 |-----------------+------------+---------|
67 | pspace1 (prog1) | inf1(pid1) | aspace1 |
68 |-----------------+------------+---------|
69 | pspace2 (prog1) | inf2(pid2) | aspace2 |
70 |-----------------+------------+---------|
72 However, had inf1 from the latter case vforked instead, it would
73 share the program and address spaces with its parent, until it
74 execs or exits, like so:
76 |-----------------+------------+---------|
77 | pspace1 (prog1) | inf1(pid1) | aspace1 |
79 |-----------------+------------+---------|
81 When the vfork child execs, it is finally given new program and
84 |-----------------+------------+---------|
85 | pspace1 (prog1) | inf1(pid1) | aspace1 |
86 |-----------------+------------+---------|
87 | pspace2 (prog1) | inf2(pid2) | aspace2 |
88 |-----------------+------------+---------|
90 There are targets where the OS (if any) doesn't provide memory
91 management or VM protection, where all inferiors share the same
92 address space --- e.g. uClinux. GDB models this by having all
93 inferiors share the same address space, but, giving each its own
94 program space, like so:
96 |-----------------+------------+---------|
97 | pspace1 (prog1) | inf1(pid1) | |
98 |-----------------+------------+ |
99 | pspace2 (prog1) | inf2(pid2) | aspace1 |
100 |-----------------+------------+ |
101 | pspace3 (prog2) | inf3(pid3) | |
102 |-----------------+------------+---------|
104 The address space sharing matters for run control and breakpoints
105 management. E.g., did we just hit a known breakpoint that we need
106 to step over? Is this breakpoint a duplicate of this other one, or
107 do I need to insert a trap?
109 Then, there are targets where all symbols look the same for all
110 inferiors, although each has its own address space, as e.g.,
111 Ericsson DICOS. In such case, the model is:
113 |---------+------------+---------|
114 | | inf1(pid1) | aspace1 |
115 | +------------+---------|
116 | pspace | inf2(pid2) | aspace2 |
117 | +------------+---------|
118 | | inf3(pid3) | aspace3 |
119 |---------+------------+---------|
121 Note however, that the DICOS debug API takes care of making GDB
122 believe that breakpoints are "global". That is, although each
123 process does have its own private copy of data symbols (just like a
124 bunch of forks), to the breakpoints module, all processes share a
125 single address space, so all breakpoints set at the same address
126 are duplicates of each other, even breakpoints set in the data
127 space (e.g., call dummy breakpoints placed on stack). This allows
128 a simplification in the spaces implementation: we avoid caring for
129 a many-many links between address and program spaces. Either
130 there's a single address space bound to the program space
131 (traditional unix/uClinux), or, in the DICOS case, the address
132 space bound to the program space is mostly ignored. */
134 /* The program space structure. */
138 program_space (address_space
*aspace_
);
141 typedef next_adapter
<struct objfile
> objfiles_range
;
143 /* Return an iterable object that can be used to iterate over all
144 objfiles. The basic use is in a foreach, like:
146 for (objfile *objf : pspace->objfiles ()) { ... } */
147 objfiles_range
objfiles ()
149 return objfiles_range (objfiles_head
);
152 typedef next_adapter
<struct objfile
,
153 basic_safe_iterator
<next_iterator
<objfile
>>>
156 /* An iterable object that can be used to iterate over all objfiles.
157 The basic use is in a foreach, like:
159 for (objfile *objf : pspace->objfiles_safe ()) { ... }
161 This variant uses a basic_safe_iterator so that objfiles can be
162 deleted during iteration. */
163 objfiles_safe_range
objfiles_safe ()
165 return objfiles_safe_range (objfiles_head
);
168 /* Add OBJFILE to the list of objfiles, putting it just before
169 BEFORE. If BEFORE is nullptr, it will go at the end of the
171 void add_objfile (struct objfile
*objfile
, struct objfile
*before
);
173 /* Remove OBJFILE from the list of objfiles. */
174 void remove_objfile (struct objfile
*objfile
);
176 /* Return true if there is more than one object file loaded; false
178 bool multi_objfile_p () const;
181 /* Pointer to next in linked list. */
182 struct program_space
*next
= NULL
;
184 /* Unique ID number. */
187 /* The main executable loaded into this program space. This is
188 managed by the exec target. */
190 /* The BFD handle for the main executable. */
192 /* The last-modified time, from when the exec was brought in. */
194 /* Similar to bfd_get_filename (exec_bfd) but in original form given
195 by user, without symbolic links and pathname resolved.
196 It needs to be freed by xfree. It is not NULL iff EBFD is not NULL. */
197 char *pspace_exec_filename
= NULL
;
199 /* Binary file diddling handle for the core file. */
200 gdb_bfd_ref_ptr cbfd
;
202 /* The address space attached to this program space. More than one
203 program space may be bound to the same address space. In the
204 traditional unix-like debugging scenario, this will usually
205 match the address space bound to the inferior, and is mostly
206 used by the breakpoints module for address matches. If the
207 target shares a program space for all inferiors and breakpoints
208 are global, then this field is ignored (we don't currently
209 support inferiors sharing a program space if the target doesn't
210 make breakpoints global). */
211 struct address_space
*aspace
= NULL
;
213 /* True if this program space's section offsets don't yet represent
214 the final offsets of the "live" address space (that is, the
215 section addresses still require the relocation offsets to be
216 applied, and hence we can't trust the section addresses for
217 anything that pokes at live memory). E.g., for qOffsets
218 targets, or for PIE executables, until we connect and ask the
219 target for the final relocation offsets, the symbols we've used
220 to set breakpoints point at the wrong addresses. */
221 int executing_startup
= 0;
223 /* True if no breakpoints should be inserted in this program
225 int breakpoints_not_allowed
= 0;
227 /* The object file that the main symbol table was loaded from
228 (e.g. the argument to the "symbol-file" or "file" command). */
229 struct objfile
*symfile_object_file
= NULL
;
231 /* All known objfiles are kept in a linked list. This points to
232 the head of this list. */
233 struct objfile
*objfiles_head
= NULL
;
235 /* The set of target sections matching the sections mapped into
236 this program space. Managed by both exec_ops and solib.c. */
237 struct target_section_table target_sections
{};
239 /* List of shared objects mapped into this space. Managed by
241 struct so_list
*so_list
= NULL
;
243 /* Number of calls to solib_add. */
244 unsigned int solib_add_generation
= 0;
246 /* When an solib is added, it is also added to this vector. This
247 is so we can properly report solib changes to the user. */
248 std::vector
<struct so_list
*> added_solibs
;
250 /* When an solib is removed, its name is added to this vector.
251 This is so we can properly report solib changes to the user. */
252 std::vector
<std::string
> deleted_solibs
;
254 /* Per pspace data-pointers required by other GDB modules. */
258 /* An address space. It is used for comparing if
259 pspaces/inferior/threads see the same address space and for
260 associating caches to each address space. */
265 /* Per aspace data-pointers required by other GDB modules. */
269 /* The object file that the main symbol table was loaded from (e.g. the
270 argument to the "symbol-file" or "file" command). */
272 #define symfile_objfile current_program_space->symfile_object_file
274 /* All known objfiles are kept in a linked list. This points to the
275 root of this list. */
276 #define object_files current_program_space->objfiles_head
278 /* The set of target sections matching the sections mapped into the
279 current program space. */
280 #define current_target_sections (¤t_program_space->target_sections)
282 /* The list of all program spaces. There's always at least one. */
283 extern struct program_space
*program_spaces
;
285 /* The current program space. This is always non-null. */
286 extern struct program_space
*current_program_space
;
288 #define ALL_PSPACES(pspace) \
289 for ((pspace) = program_spaces; (pspace) != NULL; (pspace) = (pspace)->next)
291 /* Remove a program space from the program spaces list and release it. It is
292 an error to call this function while PSPACE is the current program space. */
293 extern void delete_program_space (struct program_space
*pspace
);
295 /* Returns the number of program spaces listed. */
296 extern int number_of_program_spaces (void);
298 /* Returns true iff there's no inferior bound to PSPACE. */
299 extern int program_space_empty_p (struct program_space
*pspace
);
301 /* Copies program space SRC to DEST. Copies the main executable file,
302 and the main symbol file. Returns DEST. */
303 extern struct program_space
*clone_program_space (struct program_space
*dest
,
304 struct program_space
*src
);
306 /* Sets PSPACE as the current program space. This is usually used
307 instead of set_current_space_and_thread when the current
308 thread/inferior is not important for the operations that follow.
309 E.g., when accessing the raw symbol tables. If memory access is
310 required, then you should use switch_to_program_space_and_thread.
311 Otherwise, it is the caller's responsibility to make sure that the
312 currently selected inferior/thread matches the selected program
314 extern void set_current_program_space (struct program_space
*pspace
);
316 /* Save/restore the current program space. */
318 class scoped_restore_current_program_space
321 scoped_restore_current_program_space ()
322 : m_saved_pspace (current_program_space
)
325 ~scoped_restore_current_program_space ()
326 { set_current_program_space (m_saved_pspace
); }
328 DISABLE_COPY_AND_ASSIGN (scoped_restore_current_program_space
);
331 program_space
*m_saved_pspace
;
334 /* Create a new address space object, and add it to the list. */
335 extern struct address_space
*new_address_space (void);
337 /* Maybe create a new address space object, and add it to the list, or
338 return a pointer to an existing address space, in case inferiors
339 share an address space. */
340 extern struct address_space
*maybe_new_address_space (void);
342 /* Returns the integer address space id of ASPACE. */
343 extern int address_space_num (struct address_space
*aspace
);
345 /* Update all program spaces matching to address spaces. The user may
346 have created several program spaces, and loaded executables into
347 them before connecting to the target interface that will create the
348 inferiors. All that happens before GDB has a chance to know if the
349 inferiors will share an address space or not. Call this after
350 having connected to the target interface and having fetched the
351 target description, to fixup the program/address spaces
353 extern void update_address_spaces (void);
355 /* Reset saved solib data at the start of an solib event. This lets
356 us properly collect the data when calling solib_add, so it can then
358 extern void clear_program_space_solib_cache (struct program_space
*);
360 /* Keep a registry of per-pspace data-pointers required by other GDB
363 DECLARE_REGISTRY (program_space
);
365 /* Keep a registry of per-aspace data-pointers required by other GDB
368 DECLARE_REGISTRY (address_space
);