gdb/inferior.h

   1 /* Variables that describe the inferior process running under GDB:
   2    Where it is, why it stopped, and how to step it.
   3
   4    Copyright (C) 1986-2020 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 3 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, see <http://www.gnu.org/licenses/>.  */
  20
  21 #if !defined (INFERIOR_H)
  22 #define INFERIOR_H 1
  23
  24 struct target_waitstatus;
  25 struct frame_info;
  26 struct ui_file;
  27 struct type;
  28 struct gdbarch;
  29 struct regcache;
  30 struct ui_out;
  31 struct terminal_info;
  32 struct target_desc_info;
  33 struct continuation;
  34 struct inferior;
  35 struct thread_info;
  36
  37 /* For bpstat.  */
  38 #include "breakpoint.h"
  39
  40 /* For enum gdb_signal.  */
  41 #include "target.h"
  42
  43 /* For struct frame_id.  */
  44 #include "frame.h"
  45
  46 /* For gdb_environ.  */
  47 #include "gdbsupport/environ.h"
  48
  49 #include "progspace.h"
  50 #include "registry.h"
  51
  52 #include "symfile-add-flags.h"
  53 #include "gdbsupport/refcounted-object.h"
  54 #include "gdbsupport/forward-scope-exit.h"
  55
  56 #include "gdbsupport/common-inferior.h"
  57 #include "gdbthread.h"
  58
  59 struct infcall_suspend_state;
  60 struct infcall_control_state;
  61
  62 extern void restore_infcall_suspend_state (struct infcall_suspend_state *);
  63 extern void restore_infcall_control_state (struct infcall_control_state *);
  64
  65 /* A deleter for infcall_suspend_state that calls
  66    restore_infcall_suspend_state.  */
  67 struct infcall_suspend_state_deleter
  68 {
  69   void operator() (struct infcall_suspend_state *state) const
  70   {
  71     try
  72       {
  73         restore_infcall_suspend_state (state);
  74       }
  75     catch (const gdb_exception_error &e)
  76       {
  77         /* If we are restoring the inferior state due to an exception,
  78            some error message will be printed.  So, only warn the user
  79            when we cannot restore during normal execution.  */
  80         if (!std::uncaught_exception ())
  81           warning (_("Failed to restore inferior state: %s"), e.what ());
  82       }
  83   }
  84 };
  85
  86 /* A unique_ptr specialization for infcall_suspend_state.  */
  87 typedef std::unique_ptr<infcall_suspend_state, infcall_suspend_state_deleter>
  88     infcall_suspend_state_up;
  89
  90 extern infcall_suspend_state_up save_infcall_suspend_state ();
  91
  92 /* A deleter for infcall_control_state that calls
  93    restore_infcall_control_state.  */
  94 struct infcall_control_state_deleter
  95 {
  96   void operator() (struct infcall_control_state *state) const
  97   {
  98     restore_infcall_control_state (state);
  99   }
 100 };
 101
 102 /* A unique_ptr specialization for infcall_control_state.  */
 103 typedef std::unique_ptr<infcall_control_state, infcall_control_state_deleter>
 104     infcall_control_state_up;
 105
 106 extern infcall_control_state_up save_infcall_control_state ();
 107
 108 extern void discard_infcall_suspend_state (struct infcall_suspend_state *);
 109 extern void discard_infcall_control_state (struct infcall_control_state *);
 110
 111 extern readonly_detached_regcache *
 112   get_infcall_suspend_state_regcache (struct infcall_suspend_state *);
 113
 114 extern void set_sigint_trap (void);
 115
 116 extern void clear_sigint_trap (void);
 117
 118 /* Set/get file name for default use for standard in/out in the inferior.  */
 119
 120 extern void set_inferior_io_terminal (const char *terminal_name);
 121 extern const char *get_inferior_io_terminal (void);
 122
 123 /* Collected pid, tid, etc. of the debugged inferior.  When there's
 124    no inferior, inferior_ptid.pid () will be 0.  */
 125
 126 extern ptid_t inferior_ptid;
 127
 128 extern void generic_mourn_inferior (void);
 129
 130 extern CORE_ADDR unsigned_pointer_to_address (struct gdbarch *gdbarch,
 131                                               struct type *type,
 132                                               const gdb_byte *buf);
 133 extern void unsigned_address_to_pointer (struct gdbarch *gdbarch,
 134                                          struct type *type, gdb_byte *buf,
 135                                          CORE_ADDR addr);
 136 extern CORE_ADDR signed_pointer_to_address (struct gdbarch *gdbarch,
 137                                             struct type *type,
 138                                             const gdb_byte *buf);
 139 extern void address_to_signed_pointer (struct gdbarch *gdbarch,
 140                                        struct type *type, gdb_byte *buf,
 141                                        CORE_ADDR addr);
 142
 143 extern void reopen_exec_file (void);
 144
 145 /* From misc files */
 146
 147 extern void default_print_registers_info (struct gdbarch *gdbarch,
 148                                           struct ui_file *file,
 149                                           struct frame_info *frame,
 150                                           int regnum, int all);
 151
 152 /* Default implementation of gdbarch_print_float_info.  Print
 153    the values of all floating point registers.  */
 154
 155 extern void default_print_float_info (struct gdbarch *gdbarch,
 156                                       struct ui_file *file,
 157                                       struct frame_info *frame,
 158                                       const char *args);
 159
 160 extern void child_terminal_info (struct target_ops *self, const char *, int);
 161
 162 extern void child_terminal_ours (struct target_ops *self);
 163
 164 extern void child_terminal_ours_for_output (struct target_ops *self);
 165
 166 extern void child_terminal_inferior (struct target_ops *self);
 167
 168 extern void child_terminal_save_inferior (struct target_ops *self);
 169
 170 extern void child_terminal_init (struct target_ops *self);
 171
 172 extern void child_terminal_init_with_pgrp (int pgrp);
 173
 174 extern void child_pass_ctrlc (struct target_ops *self);
 175
 176 extern void child_interrupt (struct target_ops *self);
 177
 178 /* From fork-child.c */
 179
 180 /* Helper function to call STARTUP_INFERIOR with PID and NUM_TRAPS.
 181    This function already calls set_executing.  Return the ptid_t from
 182    STARTUP_INFERIOR.  */
 183 extern ptid_t gdb_startup_inferior (pid_t pid, int num_traps);
 184
 185 extern char *construct_inferior_arguments (int, char **);
 186
 187 /* From infcmd.c */
 188
 189 /* Initial inferior setup.  Determines the exec file is not yet known,
 190    takes any necessary post-attaching actions, fetches the target
 191    description and syncs the shared library list.  */
 192
 193 extern void setup_inferior (int from_tty);
 194
 195 extern void post_create_inferior (struct target_ops *, int);
 196
 197 extern void attach_command (const char *, int);
 198
 199 extern const char *get_inferior_args (void);
 200
 201 extern void set_inferior_args (const char *);
 202
 203 extern void set_inferior_args_vector (int, char **);
 204
 205 extern void registers_info (const char *, int);
 206
 207 extern void continue_1 (int all_threads);
 208
 209 extern void interrupt_target_1 (int all_threads);
 210
 211 using delete_longjmp_breakpoint_cleanup
 212   = FORWARD_SCOPE_EXIT (delete_longjmp_breakpoint);
 213
 214 extern void detach_command (const char *, int);
 215
 216 extern void notice_new_inferior (struct thread_info *, int, int);
 217
 218 extern struct value *get_return_value (struct value *function,
 219                                        struct type *value_type);
 220
 221 /* Prepare for execution command.  TARGET is the target that will run
 222    the command.  BACKGROUND determines whether this is a foreground
 223    (synchronous) or background (asynchronous) command.  */
 224
 225 extern void prepare_execution_command (struct target_ops *target,
 226                                        int background);
 227
 228 /* Nonzero if stopped due to completion of a stack dummy routine.  */
 229
 230 extern enum stop_stack_kind stop_stack_dummy;
 231
 232 /* Nonzero if program stopped due to a random (unexpected) signal in
 233    inferior process.  */
 234
 235 extern int stopped_by_random_signal;
 236
 237 /* Print notices on inferior events (attach, detach, etc.), set with
 238    `set print inferior-events'.  */
 239 extern bool print_inferior_events;
 240
 241 /* Anything but NO_STOP_QUIETLY means we expect a trap and the caller
 242    will handle it themselves.  STOP_QUIETLY is used when running in
 243    the shell before the child program has been exec'd and when running
 244    through shared library loading.  STOP_QUIETLY_REMOTE is used when
 245    setting up a remote connection; it is like STOP_QUIETLY_NO_SIGSTOP
 246    except that there is no need to hide a signal.  */
 247
 248 /* STOP_QUIETLY_NO_SIGSTOP is used to handle a tricky situation with attach.
 249    When doing an attach, the kernel stops the debuggee with a SIGSTOP.
 250    On newer GNU/Linux kernels (>= 2.5.61) the handling of SIGSTOP for
 251    a ptraced process has changed.  Earlier versions of the kernel
 252    would ignore these SIGSTOPs, while now SIGSTOP is treated like any
 253    other signal, i.e. it is not muffled.
 254
 255    If the gdb user does a 'continue' after the 'attach', gdb passes
 256    the global variable stop_signal (which stores the signal from the
 257    attach, SIGSTOP) to the ptrace(PTRACE_CONT,...)  call.  This is
 258    problematic, because the kernel doesn't ignore such SIGSTOP
 259    now.  I.e. it is reported back to gdb, which in turn presents it
 260    back to the user.
 261
 262    To avoid the problem, we use STOP_QUIETLY_NO_SIGSTOP, which allows
 263    gdb to clear the value of stop_signal after the attach, so that it
 264    is not passed back down to the kernel.  */
 265
 266 enum stop_kind
 267   {
 268     NO_STOP_QUIETLY = 0,
 269     STOP_QUIETLY,
 270     STOP_QUIETLY_REMOTE,
 271     STOP_QUIETLY_NO_SIGSTOP
 272   };
 273
 274 \f
 275 /* Possible values for gdbarch_call_dummy_location.  */
 276 #define ON_STACK 1
 277 #define AT_ENTRY_POINT 4
 278
 279 /* Base class for target-specific inferior data.  */
 280
 281 struct private_inferior
 282 {
 283   virtual ~private_inferior () = 0;
 284 };
 285
 286 /* Inferior process specific part of `struct infcall_control_state'.
 287
 288    Inferior thread counterpart is `struct thread_control_state'.  */
 289
 290 struct inferior_control_state
 291 {
 292   inferior_control_state ()
 293     : stop_soon (NO_STOP_QUIETLY)
 294   {
 295   }
 296
 297   explicit inferior_control_state (enum stop_kind when)
 298     : stop_soon (when)
 299   {
 300   }
 301
 302   /* See the definition of stop_kind above.  */
 303   enum stop_kind stop_soon;
 304 };
 305
 306 /* Return a pointer to the current inferior.  */
 307 extern inferior *current_inferior ();
 308
 309 extern void set_current_inferior (inferior *);
 310
 311 /* GDB represents the state of each program execution with an object
 312    called an inferior.  An inferior typically corresponds to a process
 313    but is more general and applies also to targets that do not have a
 314    notion of processes.  Each run of an executable creates a new
 315    inferior, as does each attachment to an existing process.
 316    Inferiors have unique internal identifiers that are different from
 317    target process ids.  Each inferior may in turn have multiple
 318    threads running in it.
 319
 320    Inferiors are intrusively refcounted objects.  Unlike thread
 321    objects, being the user-selected inferior is considered a strong
 322    reference and is thus accounted for in the inferior object's
 323    refcount (see set_current_inferior).  When GDB needs to remember
 324    the selected inferior to later restore it, GDB temporarily bumps
 325    the inferior object's refcount, to prevent something deleting the
 326    inferior object before reverting back (e.g., due to a
 327    "remove-inferiors" command (see
 328    scoped_restore_current_inferior).  All other inferior
 329    references are considered weak references.  Inferiors are always
 330    listed exactly once in the inferior list, so placing an inferior in
 331    the inferior list is an implicit, not counted strong reference.  */
 332
 333 class inferior : public refcounted_object
 334 {
 335 public:
 336   explicit inferior (int pid);
 337   ~inferior ();
 338
 339   /* Returns true if we can delete this inferior.  */
 340   bool deletable () const { return refcount () == 0; }
 341
 342   bool has_execution ()
 343   { return target_has_execution_1 (this); }
 344
 345   /* Pointer to next inferior in singly-linked list of inferiors.  */
 346   struct inferior *next = NULL;
 347
 348   /* This inferior's thread list.  */
 349   thread_info *thread_list = nullptr;
 350
 351   /* Returns a range adapter covering the inferior's threads,
 352      including exited threads.  Used like this:
 353
 354        for (thread_info *thr : inf->threads ())
 355          { .... }
 356   */
 357   inf_threads_range threads ()
 358   { return inf_threads_range (this->thread_list); }
 359
 360   /* Returns a range adapter covering the inferior's non-exited
 361      threads.  Used like this:
 362
 363        for (thread_info *thr : inf->non_exited_threads ())
 364          { .... }
 365   */
 366   inf_non_exited_threads_range non_exited_threads ()
 367   { return inf_non_exited_threads_range (this->thread_list); }
 368
 369   /* Like inferior::threads(), but returns a range adapter that can be
 370      used with range-for, safely.  I.e., it is safe to delete the
 371      currently-iterated thread, like this:
 372
 373      for (thread_info *t : inf->threads_safe ())
 374        if (some_condition ())
 375          delete f;
 376   */
 377   inline safe_inf_threads_range threads_safe ()
 378   { return safe_inf_threads_range (this->thread_list); }
 379
 380   /* Convenient handle (GDB inferior id).  Unique across all
 381      inferiors.  */
 382   int num = 0;
 383
 384   /* Actual target inferior id, usually, a process id.  This matches
 385      the ptid_t.pid member of threads of this inferior.  */
 386   int pid = 0;
 387   /* True if the PID was actually faked by GDB.  */
 388   bool fake_pid_p = false;
 389
 390   /* The highest thread number this inferior ever had.  */
 391   int highest_thread_num = 0;
 392
 393   /* State of GDB control of inferior process execution.
 394      See `struct inferior_control_state'.  */
 395   inferior_control_state control;
 396
 397   /* True if this was an auto-created inferior, e.g. created from
 398      following a fork; false, if this inferior was manually added by
 399      the user, and we should not attempt to prune it
 400      automatically.  */
 401   bool removable = false;
 402
 403   /* The address space bound to this inferior.  */
 404   struct address_space *aspace = NULL;
 405
 406   /* The program space bound to this inferior.  */
 407   struct program_space *pspace = NULL;
 408
 409   /* The arguments string to use when running.  */
 410   char *args = NULL;
 411
 412   /* The size of elements in argv.  */
 413   int argc = 0;
 414
 415   /* The vector version of arguments.  If ARGC is nonzero,
 416      then we must compute ARGS from this (via the target).
 417      This is always coming from main's argv and therefore
 418      should never be freed.  */
 419   char **argv = NULL;
 420
 421   /* The current working directory that will be used when starting
 422      this inferior.  */
 423   gdb::unique_xmalloc_ptr<char> cwd;
 424
 425   /* The name of terminal device to use for I/O.  */
 426   char *terminal = NULL;
 427
 428   /* The terminal state as set by the last target_terminal::terminal_*
 429      call.  */
 430   target_terminal_state terminal_state = target_terminal_state::is_ours;
 431
 432   /* Environment to use for running inferior,
 433      in format described in environ.h.  */
 434   gdb_environ environment;
 435
 436   /* True if this child process was attached rather than forked.  */
 437   bool attach_flag = false;
 438
 439   /* If this inferior is a vfork child, then this is the pointer to
 440      its vfork parent, if GDB is still attached to it.  */
 441   inferior *vfork_parent = NULL;
 442
 443   /* If this process is a vfork parent, this is the pointer to the
 444      child.  Since a vfork parent is left frozen by the kernel until
 445      the child execs or exits, a process can only have one vfork child
 446      at a given time.  */
 447   inferior *vfork_child = NULL;
 448
 449   /* True if this inferior should be detached when it's vfork sibling
 450      exits or execs.  */
 451   bool pending_detach = false;
 452
 453   /* True if this inferior is a vfork parent waiting for a vfork child
 454      not under our control to be done with the shared memory region,
 455      either by exiting or execing.  */
 456   bool waiting_for_vfork_done = false;
 457
 458   /* True if we're in the process of detaching from this inferior.  */
 459   bool detaching = false;
 460
 461   /* What is left to do for an execution command after any thread of
 462      this inferior stops.  For continuations associated with a
 463      specific thread, see `struct thread_info'.  */
 464   continuation *continuations = NULL;
 465
 466   /* True if setup_inferior wasn't called for this inferior yet.
 467      Until that is done, we must not access inferior memory or
 468      registers, as we haven't determined the target
 469      architecture/description.  */
 470   bool needs_setup = false;
 471
 472   /* Private data used by the target vector implementation.  */
 473   std::unique_ptr<private_inferior> priv;
 474
 475   /* HAS_EXIT_CODE is true if the inferior exited with an exit code.
 476      In this case, the EXIT_CODE field is also valid.  */
 477   bool has_exit_code = false;
 478   LONGEST exit_code = 0;
 479
 480   /* Default flags to pass to the symbol reading functions.  These are
 481      used whenever a new objfile is created.  */
 482   symfile_add_flags symfile_flags = 0;
 483
 484   /* Info about an inferior's target description (if it's fetched; the
 485      user supplied description's filename, if any; etc.).  */
 486   target_desc_info *tdesc_info = NULL;
 487
 488   /* The architecture associated with the inferior through the
 489      connection to the target.
 490
 491      The architecture vector provides some information that is really
 492      a property of the inferior, accessed through a particular target:
 493      ptrace operations; the layout of certain RSP packets; the
 494      solib_ops vector; etc.  To differentiate architecture accesses to
 495      per-inferior/target properties from
 496      per-thread/per-frame/per-objfile properties, accesses to
 497      per-inferior/target properties should be made through
 498      this gdbarch.  */
 499   struct gdbarch *gdbarch = NULL;
 500
 501   /* Data related to displaced stepping.  */
 502   displaced_step_inferior_state displaced_step_state;
 503
 504   /* Per inferior data-pointers required by other GDB modules.  */
 505   REGISTRY_FIELDS;
 506 };
 507
 508 /* Keep a registry of per-inferior data-pointers required by other GDB
 509    modules.  */
 510
 511 DECLARE_REGISTRY (inferior);
 512
 513 /* Add an inferior to the inferior list, print a message that a new
 514    inferior is found, and return the pointer to the new inferior.
 515    Caller may use this pointer to initialize the private inferior
 516    data.  */
 517 extern struct inferior *add_inferior (int pid);
 518
 519 /* Same as add_inferior, but don't print new inferior notifications to
 520    the CLI.  */
 521 extern struct inferior *add_inferior_silent (int pid);
 522
 523 extern void delete_inferior (struct inferior *todel);
 524
 525 /* Delete an existing inferior list entry, due to inferior detaching.  */
 526 extern void detach_inferior (inferior *inf);
 527
 528 extern void exit_inferior (inferior *inf);
 529
 530 extern void exit_inferior_silent (inferior *inf);
 531
 532 extern void exit_inferior_num_silent (int num);
 533
 534 extern void inferior_appeared (struct inferior *inf, int pid);
 535
 536 /* Get rid of all inferiors.  */
 537 extern void discard_all_inferiors (void);
 538
 539 /* Search function to lookup an inferior by target 'pid'.  */
 540 extern struct inferior *find_inferior_pid (int pid);
 541
 542 /* Search function to lookup an inferior whose pid is equal to 'ptid.pid'. */
 543 extern struct inferior *find_inferior_ptid (ptid_t ptid);
 544
 545 /* Search function to lookup an inferior by GDB 'num'.  */
 546 extern struct inferior *find_inferior_id (int num);
 547
 548 /* Find an inferior bound to PSPACE, giving preference to the current
 549    inferior.  */
 550 extern struct inferior *
 551   find_inferior_for_program_space (struct program_space *pspace);
 552
 553 /* Inferior iterator function.
 554
 555    Calls a callback function once for each inferior, so long as the
 556    callback function returns false.  If the callback function returns
 557    true, the iteration will end and the current inferior will be
 558    returned.  This can be useful for implementing a search for a
 559    inferior with arbitrary attributes, or for applying some operation
 560    to every inferior.
 561
 562    It is safe to delete the iterated inferior from the callback.  */
 563 extern struct inferior *iterate_over_inferiors (int (*) (struct inferior *,
 564                                                          void *),
 565                                                 void *);
 566
 567 /* Returns true if the inferior list is not empty.  */
 568 extern int have_inferiors (void);
 569
 570 /* Returns the number of live inferiors (real live processes).  */
 571 extern int number_of_live_inferiors (void);
 572
 573 /* Returns true if there are any live inferiors in the inferior list
 574    (not cores, not executables, real live processes).  */
 575 extern int have_live_inferiors (void);
 576
 577 /* Save/restore the current inferior.  */
 578
 579 class scoped_restore_current_inferior
 580 {
 581 public:
 582   scoped_restore_current_inferior ()
 583     : m_saved_inf (current_inferior ())
 584   {}
 585
 586   ~scoped_restore_current_inferior ()
 587   { set_current_inferior (m_saved_inf); }
 588
 589   DISABLE_COPY_AND_ASSIGN (scoped_restore_current_inferior);
 590
 591 private:
 592   inferior *m_saved_inf;
 593 };
 594
 595
 596 /* Traverse all inferiors.  */
 597
 598 extern struct inferior *inferior_list;
 599
 600 /* Pull in the internals of the inferiors ranges and iterators.  Must
 601    be done after struct inferior is defined.  */
 602 #include "inferior-iter.h"
 603
 604 /* Return a range that can be used to walk over all inferiors
 605    inferiors, with range-for, safely.  I.e., it is safe to delete the
 606    currently-iterated inferior.  When combined with range-for, this
 607    allow convenient patterns like this:
 608
 609      for (inferior *inf : all_inferiors_safe ())
 610        if (some_condition ())
 611          delete inf;
 612 */
 613
 614 inline all_inferiors_safe_range
 615 all_inferiors_safe ()
 616 {
 617   return {};
 618 }
 619
 620 /* Returns a range representing all inferiors, suitable to use with
 621    range-for, like this:
 622
 623    for (inferior *inf : all_inferiors ())
 624      [...]
 625 */
 626
 627 inline all_inferiors_range
 628 all_inferiors ()
 629 {
 630   return {};
 631 }
 632
 633 /* Return a range that can be used to walk over all inferiors with PID
 634    not zero, with range-for.  */
 635
 636 inline all_non_exited_inferiors_range
 637 all_non_exited_inferiors ()
 638 {
 639   return {};
 640 }
 641
 642 /* Prune away automatically added inferiors that aren't required
 643    anymore.  */
 644 extern void prune_inferiors (void);
 645
 646 extern int number_of_inferiors (void);
 647
 648 extern struct inferior *add_inferior_with_spaces (void);
 649
 650 /* Print the current selected inferior.  */
 651 extern void print_selected_inferior (struct ui_out *uiout);
 652
 653 #endif /* !defined (INFERIOR_H) */