gdb/progspace.h

   1 /* Program and address space management, for GDB, the GNU debugger.
   2
   3    Copyright (C) 2009-2013 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   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.
  11
  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.
  16
  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/>.  */
  19
  20
  21 #ifndef PROGSPACE_H
  22 #define PROGSPACE_H
  23
  24 #include "target.h"
  25 #include "vec.h"
  26 #include "gdb_vecs.h"
  27 #include "registry.h"
  28
  29 struct target_ops;
  30 struct bfd;
  31 struct objfile;
  32 struct inferior;
  33 struct exec;
  34 struct address_space;
  35 struct program_space_data;
  36
  37 typedef struct so_list *so_list_ptr;
  38 DEF_VEC_P (so_list_ptr);
  39
  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.
  45
  46    In the traditional debugging scenario, there's a 1-1 correspondence
  47    among program spaces, inferiors and address spaces, like so:
  48
  49      pspace1 (prog1) <--> inf1(pid1) <--> aspace1
  50
  51    In the case of debugging more than one traditional unix process or
  52    program, we still have:
  53
  54      |-----------------+------------+---------|
  55      | pspace1 (prog1) | inf1(pid1) | aspace1 |
  56      |----------------------------------------|
  57      | pspace2 (prog1) | no inf yet | aspace2 |
  58      |-----------------+------------+---------|
  59      | pspace3 (prog2) | inf2(pid2) | aspace3 |
  60      |-----------------+------------+---------|
  61
  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:
  65
  66      |-----------------+------------+---------|
  67      | pspace1 (prog1) | inf1(pid1) | aspace1 |
  68      |-----------------+------------+---------|
  69      | pspace2 (prog1) | inf2(pid2) | aspace2 |
  70      |-----------------+------------+---------|
  71
  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:
  75
  76      |-----------------+------------+---------|
  77      | pspace1 (prog1) | inf1(pid1) | aspace1 |
  78      |                 | inf2(pid2) |         |
  79      |-----------------+------------+---------|
  80
  81    When the vfork child execs, it is finally given new program and
  82    address spaces.
  83
  84      |-----------------+------------+---------|
  85      | pspace1 (prog1) | inf1(pid1) | aspace1 |
  86      |-----------------+------------+---------|
  87      | pspace2 (prog1) | inf2(pid2) | aspace2 |
  88      |-----------------+------------+---------|
  89
  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:
  95
  96      |-----------------+------------+---------|
  97      | pspace1 (prog1) | inf1(pid1) |         |
  98      |-----------------+------------+         |
  99      | pspace2 (prog1) | inf2(pid2) | aspace1 |
 100      |-----------------+------------+         |
 101      | pspace3 (prog2) | inf3(pid3) |         |
 102      |-----------------+------------+---------|
 103
 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?
 108
 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:
 112
 113      |---------+------------+---------|
 114      |         | inf1(pid1) | aspace1 |
 115      |         +------------+---------|
 116      | pspace  | inf2(pid2) | aspace2 |
 117      |         +------------+---------|
 118      |         | inf3(pid3) | aspace3 |
 119      |---------+------------+---------|
 120
 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.  */
 133
 134 /* The program space structure.  */
 135
 136 struct program_space
 137   {
 138     /* Pointer to next in linked list.  */
 139     struct program_space *next;
 140
 141     /* Unique ID number.  */
 142     int num;
 143
 144     /* The main executable loaded into this program space.  This is
 145        managed by the exec target.  */
 146
 147     /* The BFD handle for the main executable.  */
 148     bfd *ebfd;
 149     /* The last-modified time, from when the exec was brought in.  */
 150     long ebfd_mtime;
 151     /* Similar to bfd_get_filename (exec_bfd) but in original form given
 152        by user, without symbolic links and pathname resolved.
 153        It needs to be freed by xfree.  It is not NULL iff EBFD is not NULL.  */
 154     char *pspace_exec_filename;
 155
 156     /* The address space attached to this program space.  More than one
 157        program space may be bound to the same address space.  In the
 158        traditional unix-like debugging scenario, this will usually
 159        match the address space bound to the inferior, and is mostly
 160        used by the breakpoints module for address matches.  If the
 161        target shares a program space for all inferiors and breakpoints
 162        are global, then this field is ignored (we don't currently
 163        support inferiors sharing a program space if the target doesn't
 164        make breakpoints global).  */
 165     struct address_space *aspace;
 166
 167     /* True if this program space's section offsets don't yet represent
 168        the final offsets of the "live" address space (that is, the
 169        section addresses still require the relocation offsets to be
 170        applied, and hence we can't trust the section addresses for
 171        anything that pokes at live memory).  E.g., for qOffsets
 172        targets, or for PIE executables, until we connect and ask the
 173        target for the final relocation offsets, the symbols we've used
 174        to set breakpoints point at the wrong addresses.  */
 175     int executing_startup;
 176
 177     /* True if no breakpoints should be inserted in this program
 178        space.  */
 179     int breakpoints_not_allowed;
 180
 181     /* The object file that the main symbol table was loaded from
 182        (e.g. the argument to the "symbol-file" or "file" command).  */
 183     struct objfile *symfile_object_file;
 184
 185     /* All known objfiles are kept in a linked list.  This points to
 186        the head of this list.  */
 187     struct objfile *objfiles;
 188
 189     /* The set of target sections matching the sections mapped into
 190        this program space.  Managed by both exec_ops and solib.c.  */
 191     struct target_section_table target_sections;
 192
 193     /* List of shared objects mapped into this space.  Managed by
 194        solib.c.  */
 195     struct so_list *so_list;
 196
 197     /* Number of calls to solib_add.  */
 198     unsigned solib_add_generation;
 199
 200     /* When an solib is added, it is also added to this vector.  This
 201        is so we can properly report solib changes to the user.  */
 202     VEC (so_list_ptr) *added_solibs;
 203
 204     /* When an solib is removed, its name is added to this vector.
 205        This is so we can properly report solib changes to the user.  */
 206     VEC (char_ptr) *deleted_solibs;
 207
 208     /* Per pspace data-pointers required by other GDB modules.  */
 209     REGISTRY_FIELDS;
 210   };
 211
 212 /* The object file that the main symbol table was loaded from (e.g. the
 213    argument to the "symbol-file" or "file" command).  */
 214
 215 #define symfile_objfile current_program_space->symfile_object_file
 216
 217 /* All known objfiles are kept in a linked list.  This points to the
 218    root of this list.  */
 219 #define object_files current_program_space->objfiles
 220
 221 /* The set of target sections matching the sections mapped into the
 222    current program space.  */
 223 #define current_target_sections (&current_program_space->target_sections)
 224
 225 /* The list of all program spaces.  There's always at least one.  */
 226 extern struct program_space *program_spaces;
 227
 228 /* The current program space.  This is always non-null.  */
 229 extern struct program_space *current_program_space;
 230
 231 #define ALL_PSPACES(pspace) \
 232   for ((pspace) = program_spaces; (pspace) != NULL; (pspace) = (pspace)->next)
 233
 234 /* Add a new empty program space, and assign ASPACE to it.  Returns the
 235    pointer to the new object.  */
 236 extern struct program_space *add_program_space (struct address_space *aspace);
 237
 238 /* Release PSPACE and removes it from the pspace list.  */
 239 extern void remove_program_space (struct program_space *pspace);
 240
 241 /* Returns the number of program spaces listed.  */
 242 extern int number_of_program_spaces (void);
 243
 244 /* Copies program space SRC to DEST.  Copies the main executable file,
 245    and the main symbol file.  Returns DEST.  */
 246 extern struct program_space *clone_program_space (struct program_space *dest,
 247                                                 struct program_space *src);
 248
 249 /* Save the current program space so that it may be restored by a later
 250    call to do_cleanups.  Returns the struct cleanup pointer needed for
 251    later doing the cleanup.  */
 252 extern struct cleanup *save_current_program_space (void);
 253
 254 /* Sets PSPACE as the current program space.  This is usually used
 255    instead of set_current_space_and_thread when the current
 256    thread/inferior is not important for the operations that follow.
 257    E.g., when accessing the raw symbol tables.  If memory access is
 258    required, then you should use switch_to_program_space_and_thread.
 259    Otherwise, it is the caller's responsibility to make sure that the
 260    currently selected inferior/thread matches the selected program
 261    space.  */
 262 extern void set_current_program_space (struct program_space *pspace);
 263
 264 /* Saves the current thread (may be null), frame and program space in
 265    the current cleanup chain.  */
 266 extern struct cleanup *save_current_space_and_thread (void);
 267
 268 /* Switches full context to program space PSPACE.  Switches to the
 269    first thread found bound to PSPACE.  */
 270 extern void switch_to_program_space_and_thread (struct program_space *pspace);
 271
 272 /* Create a new address space object, and add it to the list.  */
 273 extern struct address_space *new_address_space (void);
 274
 275 /* Maybe create a new address space object, and add it to the list, or
 276    return a pointer to an existing address space, in case inferiors
 277    share an address space.  */
 278 extern struct address_space *maybe_new_address_space (void);
 279
 280 /* Returns the integer address space id of ASPACE.  */
 281 extern int address_space_num (struct address_space *aspace);
 282
 283 /* Update all program spaces matching to address spaces.  The user may
 284    have created several program spaces, and loaded executables into
 285    them before connecting to the target interface that will create the
 286    inferiors.  All that happens before GDB has a chance to know if the
 287    inferiors will share an address space or not.  Call this after
 288    having connected to the target interface and having fetched the
 289    target description, to fixup the program/address spaces
 290    mappings.  */
 291 extern void update_address_spaces (void);
 292
 293 /* Prune away automatically added program spaces that aren't required
 294    anymore.  */
 295 extern void prune_program_spaces (void);
 296
 297 /* Reset saved solib data at the start of an solib event.  This lets
 298    us properly collect the data when calling solib_add, so it can then
 299    later be printed.  */
 300 extern void clear_program_space_solib_cache (struct program_space *);
 301
 302 /* Keep a registry of per-pspace data-pointers required by other GDB
 303    modules.  */
 304
 305 DECLARE_REGISTRY (program_space);
 306
 307 #endif