1 /* Program and address space management, for GDB, the GNU debugger. 2 3 Copyright (C) 2009, 2010 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 27 struct target_ops; 28 struct bfd; 29 struct objfile; 30 struct inferior; 31 struct exec; 32 struct address_space; 33 struct program_space_data; 34 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. 40 41 In the traditional debugging scenario, there's a 1-1 correspondence 42 among program spaces, inferiors and address spaces, like so: 43 44 pspace1 (prog1) <--> inf1(pid1) <--> aspace1 45 46 In the case of debugging more than one traditional unix process or 47 program, we still have: 48 49 |-----------------+------------+---------| 50 | pspace1 (prog1) | inf1(pid1) | aspace1 | 51 |----------------------------------------| 52 | pspace2 (prog1) | no inf yet | aspace2 | 53 |-----------------+------------+---------| 54 | pspace3 (prog2) | inf2(pid2) | aspace3 | 55 |-----------------+------------+---------| 56 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: 60 61 |-----------------+------------+---------| 62 | pspace1 (prog1) | inf1(pid1) | aspace1 | 63 |-----------------+------------+---------| 64 | pspace2 (prog1) | inf2(pid2) | aspace2 | 65 |-----------------+------------+---------| 66 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: 70 71 |-----------------+------------+---------| 72 | pspace1 (prog1) | inf1(pid1) | aspace1 | 73 | | inf2(pid2) | | 74 |-----------------+------------+---------| 75 76 When the vfork child execs, it is finally given new program and 77 address spaces. 78 79 |-----------------+------------+---------| 80 | pspace1 (prog1) | inf1(pid1) | aspace1 | 81 |-----------------+------------+---------| 82 | pspace2 (prog1) | inf2(pid2) | aspace2 | 83 |-----------------+------------+---------| 84 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: 90 91 |-----------------+------------+---------| 92 | pspace1 (prog1) | inf1(pid1) | | 93 |-----------------+------------+ | 94 | pspace2 (prog1) | inf2(pid2) | aspace1 | 95 |-----------------+------------+ | 96 | pspace3 (prog2) | inf3(pid3) | | 97 |-----------------+------------+---------| 98 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? 103 104 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: 107 108 |---------+------------+---------| 109 | | inf1(pid1) | aspace1 | 110 | +------------+---------| 111 | pspace | inf2(pid2) | aspace2 | 112 | +------------+---------| 113 | | inf3(pid3) | aspace3 | 114 |---------+------------+---------| 115 116 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. */ 128 129 /* The program space structure. */ 130 131 struct program_space 132 { 133 /* Pointer to next in linked list. */ 134 struct program_space *next; 135 136 /* Unique ID number. */ 137 int num; 138 139 /* The main executable loaded into this program space. This is 140 managed by the exec target. */ 141 142 /* The BFD handle for the main executable. */ 143 bfd *ebfd; 144 /* The last-modified time, from when the exec was brought in. */ 145 long ebfd_mtime; 146 147 /* 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; 157 158 /* 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; 167 168 /* True if no breakpoints should be inserted in this program 169 space. */ 170 int breakpoints_not_allowed; 171 172 /* 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; 175 176 /* All known objfiles are kept in a linked list. This points to 177 the head of this list. */ 178 struct objfile *objfiles; 179 180 /* 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; 183 184 /* List of shared objects mapped into this space. Managed by 185 solib.c. */ 186 struct so_list *so_list; 187 188 /* Per pspace data-pointers required by other GDB modules. */ 189 void **data; 190 unsigned num_data; 191 }; 192 193 /* The object file that the main symbol table was loaded from (e.g. the 194 argument to the "symbol-file" or "file" command). */ 195 196 #define symfile_objfile current_program_space->symfile_object_file 197 198 /* 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 201 202 /* 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) 205 206 /* The list of all program spaces. There's always at least one. */ 207 extern struct program_space *program_spaces; 208 209 /* The current program space. This is always non-null. */ 210 extern struct program_space *current_program_space; 211 212 #define ALL_PSPACES(pspace) \ 213 for ((pspace) = program_spaces; (pspace) != NULL; (pspace) = (pspace)->next) 214 215 /* 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); 218 219 /* Release PSPACE and removes it from the pspace list. */ 220 extern void remove_program_space (struct program_space *pspace); 221 222 /* Returns the number of program spaces listed. */ 223 extern int number_of_program_spaces (void); 224 225 /* 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); 229 230 /* 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); 234 235 /* 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 242 space. */ 243 extern void set_current_program_space (struct program_space *pspace); 244 245 /* 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); 248 249 /* 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); 252 253 /* Create a new address space object, and add it to the list. */ 254 extern struct address_space *new_address_space (void); 255 256 /* 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); 260 261 /* Returns the integer address space id of ASPACE. */ 262 extern int address_space_num (struct address_space *aspace); 263 264 /* 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 271 mappings. */ 272 extern void update_address_spaces (void); 273 274 /* Prune away automatically added program spaces that aren't required 275 anymore. */ 276 extern void prune_program_spaces (void); 277 278 /* Keep a registry of per-pspace data-pointers required by other GDB 279 modules. */ 280 281 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); 289 290 #endif 291