gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2020 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef GDBSERVER_LINUX_LOW_H
  20 #define GDBSERVER_LINUX_LOW_H
  21
  22 #include "nat/linux-nat.h"
  23 #include "nat/gdb_thread_db.h"
  24 #include <signal.h>
  25
  26 #include "gdbthread.h"
  27 #include "gdb_proc_service.h"
  28
  29 /* Included for ptrace type definitions.  */
  30 #include "nat/linux-ptrace.h"
  31 #include "target/waitstatus.h" /* For enum target_stop_reason.  */
  32 #include "tracepoint.h"
  33
  34 #include <list>
  35
  36 #define PTRACE_XFER_TYPE long
  37
  38 #ifdef HAVE_LINUX_REGSETS
  39 typedef void (*regset_fill_func) (struct regcache *, void *);
  40 typedef void (*regset_store_func) (struct regcache *, const void *);
  41 enum regset_type {
  42   GENERAL_REGS,
  43   FP_REGS,
  44   EXTENDED_REGS,
  45   OPTIONAL_REGS, /* Do not error if the regset cannot be accessed.  */
  46 };
  47
  48 /* The arch's regsets array initializer must be terminated with a NULL
  49    regset.  */
  50 #define NULL_REGSET \
  51   { 0, 0, 0, -1, (enum regset_type) -1, nullptr, nullptr, nullptr, nullptr }
  52
  53 struct regset_info
  54 {
  55   int get_request, set_request;
  56   /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
  57      argument and the 4th argument should be "const struct iovec *".  */
  58   int nt_type;
  59   int size;
  60   enum regset_type type;
  61   regset_fill_func fill_function;
  62   regset_store_func store_function;
  63   /* The name of the sysctl flag that controls read/write permission for this
  64      particular register set.  If it is nullptr, it means there is no such
  65      switch.  */
  66   const char *sysctl_read_permission = nullptr;
  67   const char *sysctl_write_permission = nullptr;
  68   bool sysctl_read_should_warn = true;
  69   bool sysctl_write_should_warn = true;
  70 };
  71
  72 /* Aggregation of all the supported regsets of a given
  73    architecture/mode.  */
  74
  75 struct regsets_info
  76 {
  77   /* The regsets array.  */
  78   struct regset_info *regsets;
  79
  80   /* The number of regsets in the REGSETS array.  */
  81   int num_regsets;
  82
  83   /* If we get EIO on a regset, do not try it again.  Note the set of
  84      supported regsets may depend on processor mode on biarch
  85      machines.  This is a (lazily allocated) array holding one boolean
  86      byte (0/1) per regset, with each element corresponding to the
  87      regset in the REGSETS array above at the same offset.  */
  88   char *disabled_regsets;
  89 };
  90
  91 #endif
  92
  93 /* Mapping between the general-purpose registers in `struct user'
  94    format and GDB's register array layout.  */
  95
  96 struct usrregs_info
  97 {
  98   /* The number of registers accessible.  */
  99   int num_regs;
 100
 101   /* The registers map.  */
 102   int *regmap;
 103 };
 104
 105 /* All info needed to access an architecture/mode's registers.  */
 106
 107 struct regs_info
 108 {
 109   /* Regset support bitmap: 1 for registers that are transferred as a part
 110      of a regset, 0 for ones that need to be handled individually.  This
 111      can be NULL if all registers are transferred with regsets or regsets
 112      are not supported.  */
 113   unsigned char *regset_bitmap;
 114
 115   /* Info used when accessing registers with PTRACE_PEEKUSER /
 116      PTRACE_POKEUSER.  This can be NULL if all registers are
 117      transferred with regsets  .*/
 118   struct usrregs_info *usrregs;
 119
 120 #ifdef HAVE_LINUX_REGSETS
 121   /* Info used when accessing registers with regsets.  */
 122   struct regsets_info *regsets_info;
 123 #endif
 124 };
 125
 126 struct process_info_private
 127 {
 128   /* Arch-specific additions.  */
 129   struct arch_process_info *arch_private;
 130
 131   /* libthread_db-specific additions.  Not NULL if this process has loaded
 132      thread_db, and it is active.  */
 133   struct thread_db *thread_db;
 134
 135   /* &_r_debug.  0 if not yet determined.  -1 if no PT_DYNAMIC in Phdrs.  */
 136   CORE_ADDR r_debug;
 137 };
 138
 139 struct lwp_info;
 140
 141 struct link_map_offsets
 142 {
 143   /* Offset and size of r_debug.r_version.  */
 144   int r_version_offset;
 145
 146   /* Offset and size of r_debug.r_map.  */
 147   int r_map_offset;
 148
 149   /* Offset to l_addr field in struct link_map.  */
 150   int l_addr_offset;
 151
 152   /* Offset to l_name field in struct link_map.  */
 153   int l_name_offset;
 154
 155   /* Offset to l_ld field in struct link_map.  */
 156   int l_ld_offset;
 157
 158   /* Offset to l_next field in struct link_map.  */
 159   int l_next_offset;
 160
 161   /* Offset to l_prev field in struct link_map.  */
 162   int l_prev_offset;
 163 };
 164
 165 /* Target ops definitions for a Linux target.  */
 166
 167 class linux_process_target : public process_stratum_target
 168 {
 169 public:
 170
 171   int create_inferior (const char *program,
 172                        const std::vector<char *> &program_args) override;
 173
 174   void post_create_inferior () override;
 175
 176   int attach (unsigned long pid) override;
 177
 178   int kill (process_info *proc) override;
 179
 180   int detach (process_info *proc) override;
 181
 182   void mourn (process_info *proc) override;
 183
 184   void join (int pid) override;
 185
 186   bool thread_alive (ptid_t pid) override;
 187
 188   void resume (thread_resume *resume_info, size_t n) override;
 189
 190   ptid_t wait (ptid_t ptid, target_waitstatus *status,
 191                target_wait_flags options) override;
 192
 193   void fetch_registers (regcache *regcache, int regno) override;
 194
 195   void store_registers (regcache *regcache, int regno) override;
 196
 197   int prepare_to_access_memory () override;
 198
 199   void done_accessing_memory () override;
 200
 201   int read_memory (CORE_ADDR memaddr, unsigned char *myaddr,
 202                    int len) override;
 203
 204   int write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 205                     int len) override;
 206
 207   void look_up_symbols () override;
 208
 209   void request_interrupt () override;
 210
 211   bool supports_read_auxv () override;
 212
 213   int read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 214                  unsigned int len) override;
 215
 216   int insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 217                     int size, raw_breakpoint *bp) override;
 218
 219   int remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 220                     int size, raw_breakpoint *bp) override;
 221
 222   bool stopped_by_sw_breakpoint () override;
 223
 224   bool supports_stopped_by_sw_breakpoint () override;
 225
 226   bool stopped_by_hw_breakpoint () override;
 227
 228   bool supports_stopped_by_hw_breakpoint () override;
 229
 230   bool supports_hardware_single_step () override;
 231
 232   bool stopped_by_watchpoint () override;
 233
 234   CORE_ADDR stopped_data_address () override;
 235
 236   bool supports_read_offsets () override;
 237
 238   int read_offsets (CORE_ADDR *text, CORE_ADDR *data) override;
 239
 240   bool supports_get_tls_address () override;
 241
 242   int get_tls_address (thread_info *thread, CORE_ADDR offset,
 243                        CORE_ADDR load_module, CORE_ADDR *address) override;
 244
 245   bool supports_qxfer_osdata () override;
 246
 247   int qxfer_osdata (const char *annex, unsigned char *readbuf,
 248                     unsigned const char *writebuf,
 249                     CORE_ADDR offset, int len) override;
 250
 251   bool supports_qxfer_siginfo () override;
 252
 253   int qxfer_siginfo (const char *annex, unsigned char *readbuf,
 254                      unsigned const char *writebuf,
 255                      CORE_ADDR offset, int len) override;
 256
 257   bool supports_non_stop () override;
 258
 259   bool async (bool enable) override;
 260
 261   int start_non_stop (bool enable) override;
 262
 263   bool supports_multi_process () override;
 264
 265   bool supports_fork_events () override;
 266
 267   bool supports_vfork_events () override;
 268
 269   bool supports_exec_events () override;
 270
 271   void handle_new_gdb_connection () override;
 272
 273   int handle_monitor_command (char *mon) override;
 274
 275   int core_of_thread (ptid_t ptid) override;
 276
 277 #if defined PT_GETDSBT || defined PTRACE_GETFDPIC
 278   bool supports_read_loadmap () override;
 279
 280   int read_loadmap (const char *annex, CORE_ADDR offset,
 281                     unsigned char *myaddr, unsigned int len) override;
 282 #endif
 283
 284   CORE_ADDR read_pc (regcache *regcache) override;
 285
 286   void write_pc (regcache *regcache, CORE_ADDR pc) override;
 287
 288   bool supports_thread_stopped () override;
 289
 290   bool thread_stopped (thread_info *thread) override;
 291
 292   void pause_all (bool freeze) override;
 293
 294   void unpause_all (bool unfreeze) override;
 295
 296   void stabilize_threads () override;
 297
 298   bool supports_disable_randomization () override;
 299
 300   bool supports_qxfer_libraries_svr4 () override;
 301
 302   int qxfer_libraries_svr4 (const char *annex,
 303                             unsigned char *readbuf,
 304                             unsigned const char *writebuf,
 305                             CORE_ADDR offset, int len) override;
 306
 307   bool supports_agent () override;
 308
 309 #ifdef HAVE_LINUX_BTRACE
 310   btrace_target_info *enable_btrace (ptid_t ptid,
 311                                      const btrace_config *conf) override;
 312
 313   int disable_btrace (btrace_target_info *tinfo) override;
 314
 315   int read_btrace (btrace_target_info *tinfo, buffer *buf,
 316                    enum btrace_read_type type) override;
 317
 318   int read_btrace_conf (const btrace_target_info *tinfo,
 319                         buffer *buf) override;
 320 #endif
 321
 322   bool supports_range_stepping () override;
 323
 324   bool supports_pid_to_exec_file () override;
 325
 326   char *pid_to_exec_file (int pid) override;
 327
 328   bool supports_multifs () override;
 329
 330   int multifs_open (int pid, const char *filename, int flags,
 331                     mode_t mode) override;
 332
 333   int multifs_unlink (int pid, const char *filename) override;
 334
 335   ssize_t multifs_readlink (int pid, const char *filename, char *buf,
 336                             size_t bufsiz) override;
 337
 338   const char *thread_name (ptid_t thread) override;
 339
 340 #if USE_THREAD_DB
 341   bool thread_handle (ptid_t ptid, gdb_byte **handle,
 342                       int *handle_len) override;
 343 #endif
 344
 345   bool supports_catch_syscall () override;
 346
 347   /* Return the information to access registers.  This has public
 348      visibility because proc-service uses it.  */
 349   virtual const regs_info *get_regs_info () = 0;
 350
 351 private:
 352
 353   /* Handle a GNU/Linux extended wait response.  If we see a clone,
 354      fork, or vfork event, we need to add the new LWP to our list
 355      (and return 0 so as not to report the trap to higher layers).
 356      If we see an exec event, we will modify ORIG_EVENT_LWP to point
 357      to a new LWP representing the new program.  */
 358   int handle_extended_wait (lwp_info **orig_event_lwp, int wstat);
 359
 360   /* Do low-level handling of the event, and check if we should go on
 361      and pass it to caller code.  Return the affected lwp if we are, or
 362      NULL otherwise.  */
 363   lwp_info *filter_event (int lwpid, int wstat);
 364
 365   /* Wait for an event from child(ren) WAIT_PTID, and return any that
 366      match FILTER_PTID (leaving others pending).  The PTIDs can be:
 367      minus_one_ptid, to specify any child; a pid PTID, specifying all
 368      lwps of a thread group; or a PTID representing a single lwp.  Store
 369      the stop status through the status pointer WSTAT.  OPTIONS is
 370      passed to the waitpid call.  Return 0 if no event was found and
 371      OPTIONS contains WNOHANG.  Return -1 if no unwaited-for children
 372      was found.  Return the PID of the stopped child otherwise.  */
 373   int wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid,
 374                                int *wstatp, int options);
 375
 376   /* Wait for an event from child(ren) PTID.  PTIDs can be:
 377      minus_one_ptid, to specify any child; a pid PTID, specifying all
 378      lwps of a thread group; or a PTID representing a single lwp.  Store
 379      the stop status through the status pointer WSTAT.  OPTIONS is
 380      passed to the waitpid call.  Return 0 if no event was found and
 381      OPTIONS contains WNOHANG.  Return -1 if no unwaited-for children
 382      was found.  Return the PID of the stopped child otherwise.  */
 383   int wait_for_event (ptid_t ptid, int *wstatp, int options);
 384
 385   /* Wait for all children to stop for the SIGSTOPs we just queued.  */
 386   void wait_for_sigstop ();
 387
 388   /* Wait for process, returns status.  */
 389   ptid_t wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
 390                  target_wait_flags target_options);
 391
 392   /* Stop all lwps that aren't stopped yet, except EXCEPT, if not NULL.
 393      If SUSPEND, then also increase the suspend count of every LWP,
 394      except EXCEPT.  */
 395   void stop_all_lwps (int suspend, lwp_info *except);
 396
 397   /* Stopped LWPs that the client wanted to be running, that don't have
 398      pending statuses, are set to run again, except for EXCEPT, if not
 399      NULL.  This undoes a stop_all_lwps call.  */
 400   void unstop_all_lwps (int unsuspend, lwp_info *except);
 401
 402   /* Start a step-over operation on LWP.  When LWP stopped at a
 403      breakpoint, to make progress, we need to remove the breakpoint out
 404      of the way.  If we let other threads run while we do that, they may
 405      pass by the breakpoint location and miss hitting it.  To avoid
 406      that, a step-over momentarily stops all threads while LWP is
 407      single-stepped by either hardware or software while the breakpoint
 408      is temporarily uninserted from the inferior.  When the single-step
 409      finishes, we reinsert the breakpoint, and let all threads that are
 410      supposed to be running, run again.  */
 411   void start_step_over (lwp_info *lwp);
 412
 413   /* If there's a step over in progress, wait until all threads stop
 414      (that is, until the stepping thread finishes its step), and
 415      unsuspend all lwps.  The stepping thread ends with its status
 416      pending, which is processed later when we get back to processing
 417      events.  */
 418   void complete_ongoing_step_over ();
 419
 420   /* Finish a step-over.  Reinsert the breakpoint we had uninserted in
 421      start_step_over, if still there, and delete any single-step
 422      breakpoints we've set, on non hardware single-step targets.
 423      Return true if step over finished.  */
 424   bool finish_step_over (lwp_info *lwp);
 425
 426   /* When we finish a step-over, set threads running again.  If there's
 427      another thread that may need a step-over, now's the time to start
 428      it.  Eventually, we'll move all threads past their breakpoints.  */
 429   void proceed_all_lwps ();
 430
 431   /* The reason we resume in the caller, is because we want to be able
 432      to pass lwp->status_pending as WSTAT, and we need to clear
 433      status_pending_p before resuming, otherwise, resume_one_lwp
 434      refuses to resume.  */
 435   bool maybe_move_out_of_jump_pad (lwp_info *lwp, int *wstat);
 436
 437   /* Move THREAD out of the jump pad.  */
 438   void move_out_of_jump_pad (thread_info *thread);
 439
 440   /* Call low_arch_setup on THREAD.  */
 441   void arch_setup_thread (thread_info *thread);
 442
 443 #ifdef HAVE_LINUX_USRREGS
 444   /* Fetch one register.  */
 445   void fetch_register (const usrregs_info *usrregs, regcache *regcache,
 446                        int regno);
 447
 448   /* Store one register.  */
 449   void store_register (const usrregs_info *usrregs, regcache *regcache,
 450                        int regno);
 451 #endif
 452
 453   /* Fetch all registers, or just one, from the child process.
 454      If REGNO is -1, do this for all registers, skipping any that are
 455      assumed to have been retrieved by regsets_fetch_inferior_registers,
 456      unless ALL is non-zero.
 457      Otherwise, REGNO specifies which register (so we can save time).  */
 458   void usr_fetch_inferior_registers (const regs_info *regs_info,
 459                                      regcache *regcache, int regno, int all);
 460
 461   /* Store our register values back into the inferior.
 462      If REGNO is -1, do this for all registers, skipping any that are
 463      assumed to have been saved by regsets_store_inferior_registers,
 464      unless ALL is non-zero.
 465      Otherwise, REGNO specifies which register (so we can save time).  */
 466   void usr_store_inferior_registers (const regs_info *regs_info,
 467                                      regcache *regcache, int regno, int all);
 468
 469   /* Return the PC as read from the regcache of LWP, without any
 470      adjustment.  */
 471   CORE_ADDR get_pc (lwp_info *lwp);
 472
 473   /* Called when the LWP stopped for a signal/trap.  If it stopped for a
 474      trap check what caused it (breakpoint, watchpoint, trace, etc.),
 475      and save the result in the LWP's stop_reason field.  If it stopped
 476      for a breakpoint, decrement the PC if necessary on the lwp's
 477      architecture.  Returns true if we now have the LWP's stop PC.  */
 478   bool save_stop_reason (lwp_info *lwp);
 479
 480   /* Resume execution of LWP.  If STEP is nonzero, single-step it.  If
 481      SIGNAL is nonzero, give it that signal.  */
 482   void resume_one_lwp_throw (lwp_info *lwp, int step, int signal,
 483                              siginfo_t *info);
 484
 485   /* Like resume_one_lwp_throw, but no error is thrown if the LWP
 486      disappears while we try to resume it.  */
 487   void resume_one_lwp (lwp_info *lwp, int step, int signal, siginfo_t *info);
 488
 489   /* This function is called once per thread.  We check the thread's
 490      last resume request, which will tell us whether to resume, step, or
 491      leave the thread stopped.  Any signal the client requested to be
 492      delivered has already been enqueued at this point.
 493
 494      If any thread that GDB wants running is stopped at an internal
 495      breakpoint that needs stepping over, we start a step-over operation
 496      on that particular thread, and leave all others stopped.  */
 497   void proceed_one_lwp (thread_info *thread, lwp_info *except);
 498
 499   /* This function is called once per thread.  We check the thread's
 500      resume request, which will tell us whether to resume, step, or
 501      leave the thread stopped; and what signal, if any, it should be
 502      sent.
 503
 504      For threads which we aren't explicitly told otherwise, we preserve
 505      the stepping flag; this is used for stepping over gdbserver-placed
 506      breakpoints.
 507
 508      If pending_flags was set in any thread, we queue any needed
 509      signals, since we won't actually resume.  We already have a pending
 510      event to report, so we don't need to preserve any step requests;
 511      they should be re-issued if necessary.  */
 512   void resume_one_thread (thread_info *thread, bool leave_all_stopped);
 513
 514   /* Return true if this lwp has an interesting status pending.  */
 515   bool status_pending_p_callback (thread_info *thread, ptid_t ptid);
 516
 517   /* Resume LWPs that are currently stopped without any pending status
 518      to report, but are resumed from the core's perspective.  */
 519   void resume_stopped_resumed_lwps (thread_info *thread);
 520
 521   /* Unsuspend THREAD, except EXCEPT, and proceed.  */
 522   void unsuspend_and_proceed_one_lwp (thread_info *thread, lwp_info *except);
 523
 524   /* Return true if this lwp still has an interesting status pending.
 525      If not (e.g., it had stopped for a breakpoint that is gone), return
 526      false.  */
 527   bool thread_still_has_status_pending (thread_info *thread);
 528
 529   /* Return true if this lwp is to-be-resumed and has an interesting
 530      status pending.  */
 531   bool resume_status_pending (thread_info *thread);
 532
 533   /* Return true if this lwp that GDB wants running is stopped at an
 534      internal breakpoint that we need to step over.  It assumes that
 535      any required STOP_PC adjustment has already been propagated to
 536      the inferior's regcache.  */
 537   bool thread_needs_step_over (thread_info *thread);
 538
 539   /* Single step via hardware or software single step.
 540      Return 1 if hardware single stepping, 0 if software single stepping
 541      or can't single step.  */
 542   int single_step (lwp_info* lwp);
 543
 544   /* Return true if THREAD is doing hardware single step.  */
 545   bool maybe_hw_step (thread_info *thread);
 546
 547   /* Install breakpoints for software single stepping.  */
 548   void install_software_single_step_breakpoints (lwp_info *lwp);
 549
 550   /* Fetch the possibly triggered data watchpoint info and store it in
 551      CHILD.
 552
 553      On some archs, like x86, that use debug registers to set
 554      watchpoints, it's possible that the way to know which watched
 555      address trapped, is to check the register that is used to select
 556      which address to watch.  Problem is, between setting the watchpoint
 557      and reading back which data address trapped, the user may change
 558      the set of watchpoints, and, as a consequence, GDB changes the
 559      debug registers in the inferior.  To avoid reading back a stale
 560      stopped-data-address when that happens, we cache in LP the fact
 561      that a watchpoint trapped, and the corresponding data address, as
 562      soon as we see CHILD stop with a SIGTRAP.  If GDB changes the debug
 563      registers meanwhile, we have the cached data we can rely on.  */
 564   bool check_stopped_by_watchpoint (lwp_info *child);
 565
 566   /* Convert a native/host siginfo object, into/from the siginfo in the
 567      layout of the inferiors' architecture.  */
 568   void siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo,
 569                       int direction);
 570
 571   /* Add a process to the common process list, and set its private
 572      data.  */
 573   process_info *add_linux_process (int pid, int attached);
 574
 575   /* Add a new thread.  */
 576   lwp_info *add_lwp (ptid_t ptid);
 577
 578   /* Delete a thread.  */
 579   void delete_lwp (lwp_info *lwp);
 580
 581 public: /* Make this public because it's used from outside.  */
 582   /* Attach to an inferior process.  Returns 0 on success, ERRNO on
 583      error.  */
 584   int attach_lwp (ptid_t ptid);
 585
 586 private: /* Back to private.  */
 587   /* Detach from LWP.  */
 588   void detach_one_lwp (lwp_info *lwp);
 589
 590   /* Detect zombie thread group leaders, and "exit" them.  We can't
 591      reap their exits until all other threads in the group have
 592      exited.  */
 593   void check_zombie_leaders ();
 594
 595   /* Convenience function that is called when the kernel reports an exit
 596      event.  This decides whether to report the event to GDB as a
 597      process exit event, a thread exit event, or to suppress the
 598      event.  */
 599   ptid_t filter_exit_event (lwp_info *event_child,
 600                             target_waitstatus *ourstatus);
 601
 602   /* Returns true if THREAD is stopped in a jump pad, and we can't
 603      move it out, because we need to report the stop event to GDB.  For
 604      example, if the user puts a breakpoint in the jump pad, it's
 605      because she wants to debug it.  */
 606   bool stuck_in_jump_pad (thread_info *thread);
 607
 608   /* Convenience wrapper.  Returns information about LWP's fast tracepoint
 609      collection status.  */
 610   fast_tpoint_collect_result linux_fast_tracepoint_collecting
 611     (lwp_info *lwp, fast_tpoint_collect_status *status);
 612
 613   /* This function should only be called if LWP got a SYSCALL_SIGTRAP.
 614      Fill *SYSNO with the syscall nr trapped.  */
 615   void get_syscall_trapinfo (lwp_info *lwp, int *sysno);
 616
 617   /* Returns true if GDB is interested in the event_child syscall.
 618      Only to be called when stopped reason is SYSCALL_SIGTRAP.  */
 619   bool gdb_catch_this_syscall (lwp_info *event_child);
 620
 621 protected:
 622   /* The architecture-specific "low" methods are listed below.  */
 623
 624   /* Architecture-specific setup for the current thread.  */
 625   virtual void low_arch_setup () = 0;
 626
 627   /* Return false if we can fetch/store the register, true if we cannot
 628      fetch/store the register.  */
 629   virtual bool low_cannot_fetch_register (int regno) = 0;
 630
 631   virtual bool low_cannot_store_register (int regno) = 0;
 632
 633   /* Hook to fetch a register in some non-standard way.  Used for
 634      example by backends that have read-only registers with hardcoded
 635      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 636      REGNO was supplied, false if not, and we should fallback to the
 637      standard ptrace methods.  */
 638   virtual bool low_fetch_register (regcache *regcache, int regno);
 639
 640   /* Return true if breakpoints are supported.  Such targets must
 641      implement the GET_PC and SET_PC methods.  */
 642   virtual bool low_supports_breakpoints ();
 643
 644   virtual CORE_ADDR low_get_pc (regcache *regcache);
 645
 646   virtual void low_set_pc (regcache *regcache, CORE_ADDR newpc);
 647
 648   /* Find the next possible PCs after the current instruction executes.
 649      Targets that override this method should also override
 650      'supports_software_single_step' to return true.  */
 651   virtual std::vector<CORE_ADDR> low_get_next_pcs (regcache *regcache);
 652
 653   /* Return true if there is a breakpoint at PC.  */
 654   virtual bool low_breakpoint_at (CORE_ADDR pc) = 0;
 655
 656   /* Breakpoint and watchpoint related functions.  See target.h for
 657      comments.  */
 658   virtual int low_insert_point (raw_bkpt_type type, CORE_ADDR addr,
 659                                 int size, raw_breakpoint *bp);
 660
 661   virtual int low_remove_point (raw_bkpt_type type, CORE_ADDR addr,
 662                                 int size, raw_breakpoint *bp);
 663
 664   virtual bool low_stopped_by_watchpoint ();
 665
 666   virtual CORE_ADDR low_stopped_data_address ();
 667
 668   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 669      for registers smaller than an xfer unit).  */
 670   virtual void low_collect_ptrace_register (regcache *regcache, int regno,
 671                                             char *buf);
 672
 673   virtual void low_supply_ptrace_register (regcache *regcache, int regno,
 674                                            const char *buf);
 675
 676   /* Hook to convert from target format to ptrace format and back.
 677      Returns true if any conversion was done; false otherwise.
 678      If DIRECTION is 1, then copy from INF to NATIVE.
 679      If DIRECTION is 0, copy from NATIVE to INF.  */
 680   virtual bool low_siginfo_fixup (siginfo_t *native, gdb_byte *inf,
 681                                   int direction);
 682
 683   /* Hook to call when a new process is created or attached to.
 684      If extra per-process architecture-specific data is needed,
 685      allocate it here.  */
 686   virtual arch_process_info *low_new_process ();
 687
 688   /* Hook to call when a process is being deleted.  If extra per-process
 689      architecture-specific data is needed, delete it here.  */
 690   virtual void low_delete_process (arch_process_info *info);
 691
 692   /* Hook to call when a new thread is detected.
 693      If extra per-thread architecture-specific data is needed,
 694      allocate it here.  */
 695   virtual void low_new_thread (lwp_info *);
 696
 697   /* Hook to call when a thread is being deleted.  If extra per-thread
 698      architecture-specific data is needed, delete it here.  */
 699   virtual void low_delete_thread (arch_lwp_info *);
 700
 701   /* Hook to call, if any, when a new fork is attached.  */
 702   virtual void low_new_fork (process_info *parent, process_info *child);
 703
 704   /* Hook to call prior to resuming a thread.  */
 705   virtual void low_prepare_to_resume (lwp_info *lwp);
 706
 707   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 708      success, -1 on failure.  */
 709   virtual int low_get_thread_area (int lwpid, CORE_ADDR *addrp);
 710
 711   /* Returns true if the low target supports range stepping.  */
 712   virtual bool low_supports_range_stepping ();
 713
 714   /* Return true if the target supports catch syscall.  Such targets
 715      override the low_get_syscall_trapinfo method below.  */
 716   virtual bool low_supports_catch_syscall ();
 717
 718   /* Fill *SYSNO with the syscall nr trapped.  Only to be called when
 719      inferior is stopped due to SYSCALL_SIGTRAP.  */
 720   virtual void low_get_syscall_trapinfo (regcache *regcache, int *sysno);
 721
 722   /* How many bytes the PC should be decremented after a break.  */
 723   virtual int low_decr_pc_after_break ();
 724
 725   /* Return the linkmap offsets based on IS_ELF64.  */
 726   virtual const struct link_map_offsets *low_fetch_linkmap_offsets (int is_elf64);
 727
 728 };
 729
 730 extern linux_process_target *the_linux_target;
 731
 732 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
 733 #define get_lwp_thread(lwp) ((lwp)->thread)
 734
 735 /* Information about a signal that is to be delivered to a thread.  */
 736
 737 struct pending_signal
 738 {
 739   pending_signal (int signal)
 740     : signal {signal}
 741   {};
 742
 743   int signal;
 744   siginfo_t info;
 745 };
 746
 747 /* This struct is recorded in the target_data field of struct thread_info.
 748
 749    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 750    GDB protocol representation of the thread ID.  Threads also have
 751    a "process ID" (poorly named) which is (presently) the same as the
 752    LWP ID.
 753
 754    There is also ``all_processes'' is keyed by the "overall process ID",
 755    which GNU/Linux calls tgid, "thread group ID".  */
 756
 757 struct lwp_info
 758 {
 759   /* Backlink to the parent object.  */
 760   struct thread_info *thread;
 761
 762   /* If this flag is set, the next SIGSTOP will be ignored (the
 763      process will be immediately resumed).  This means that either we
 764      sent the SIGSTOP to it ourselves and got some other pending event
 765      (so the SIGSTOP is still pending), or that we stopped the
 766      inferior implicitly via PTRACE_ATTACH and have not waited for it
 767      yet.  */
 768   int stop_expected;
 769
 770   /* When this is true, we shall not try to resume this thread, even
 771      if last_resume_kind isn't resume_stop.  */
 772   int suspended;
 773
 774   /* If this flag is set, the lwp is known to be stopped right now (stop
 775      event already received in a wait()).  */
 776   int stopped;
 777
 778   /* Signal whether we are in a SYSCALL_ENTRY or
 779      in a SYSCALL_RETURN event.
 780      Values:
 781      - TARGET_WAITKIND_SYSCALL_ENTRY
 782      - TARGET_WAITKIND_SYSCALL_RETURN */
 783   enum target_waitkind syscall_state;
 784
 785   /* When stopped is set, the last wait status recorded for this lwp.  */
 786   int last_status;
 787
 788   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 789      this LWP's last event, to pass to GDB without any further
 790      processing.  This is used to store extended ptrace event
 791      information or exit status until it can be reported to GDB.  */
 792   struct target_waitstatus waitstatus;
 793
 794   /* A pointer to the fork child/parent relative.  Valid only while
 795      the parent fork event is not reported to higher layers.  Used to
 796      avoid wildcard vCont actions resuming a fork child before GDB is
 797      notified about the parent's fork event.  */
 798   struct lwp_info *fork_relative;
 799
 800   /* When stopped is set, this is where the lwp last stopped, with
 801      decr_pc_after_break already accounted for.  If the LWP is
 802      running, this is the address at which the lwp was resumed.  */
 803   CORE_ADDR stop_pc;
 804
 805   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 806      been reported.  */
 807   int status_pending_p;
 808   int status_pending;
 809
 810   /* The reason the LWP last stopped, if we need to track it
 811      (breakpoint, watchpoint, etc.)  */
 812   enum target_stop_reason stop_reason;
 813
 814   /* On architectures where it is possible to know the data address of
 815      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 816      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 817      is true.  */
 818   CORE_ADDR stopped_data_address;
 819
 820   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 821      stop (SIGTRAP stops only).  */
 822   CORE_ADDR bp_reinsert;
 823
 824   /* If this flag is set, the last continue operation at the ptrace
 825      level on this process was a single-step.  */
 826   int stepping;
 827
 828   /* Range to single step within.  This is a copy of the step range
 829      passed along the last resume request.  See 'struct
 830      thread_resume'.  */
 831   CORE_ADDR step_range_start;   /* Inclusive */
 832   CORE_ADDR step_range_end;     /* Exclusive */
 833
 834   /* If this flag is set, we need to set the event request flags the
 835      next time we see this LWP stop.  */
 836   int must_set_ptrace_flags;
 837
 838   /* A chain of signals that need to be delivered to this process.  */
 839   std::list<pending_signal> pending_signals;
 840
 841   /* A link used when resuming.  It is initialized from the resume request,
 842      and then processed and cleared in linux_resume_one_lwp.  */
 843   struct thread_resume *resume;
 844
 845   /* Information bout this lwp's fast tracepoint collection status (is it
 846      currently stopped in the jump pad, and if so, before or at/after the
 847      relocated instruction).  Normally, we won't care about this, but we will
 848      if a signal arrives to this lwp while it is collecting.  */
 849   fast_tpoint_collect_result collecting_fast_tracepoint;
 850
 851   /* A chain of signals that need to be reported to GDB.  These were
 852      deferred because the thread was doing a fast tracepoint collect
 853      when they arrived.  */
 854   std::list<pending_signal> pending_signals_to_report;
 855
 856   /* When collecting_fast_tracepoint is first found to be 1, we insert
 857      a exit-jump-pad-quickly breakpoint.  This is it.  */
 858   struct breakpoint *exit_jump_pad_bkpt;
 859
 860 #ifdef USE_THREAD_DB
 861   int thread_known;
 862   /* The thread handle, used for e.g. TLS access.  Only valid if
 863      THREAD_KNOWN is set.  */
 864   td_thrhandle_t th;
 865
 866   /* The pthread_t handle.  */
 867   thread_t thread_handle;
 868 #endif
 869
 870   /* Arch-specific additions.  */
 871   struct arch_lwp_info *arch_private;
 872 };
 873
 874 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 875
 876 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 877    errno).  */
 878 int linux_attach_lwp (ptid_t ptid);
 879
 880 struct lwp_info *find_lwp_pid (ptid_t ptid);
 881 /* For linux_stop_lwp see nat/linux-nat.h.  */
 882
 883 #ifdef HAVE_LINUX_REGSETS
 884 void initialize_regsets_info (struct regsets_info *regsets_info);
 885 #endif
 886
 887 void initialize_low_arch (void);
 888
 889 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 890 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 891
 892 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 893 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 894
 895 /* From thread-db.c  */
 896 int thread_db_init (void);
 897 void thread_db_detach (struct process_info *);
 898 void thread_db_mourn (struct process_info *);
 899 int thread_db_handle_monitor_command (char *);
 900 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 901                                CORE_ADDR load_module, CORE_ADDR *address);
 902 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 903
 904 /* Called from linux-low.c when a clone event is detected.  Upon entry,
 905    both the clone and the parent should be stopped.  This function does
 906    whatever is required have the clone under thread_db's control.  */
 907
 908 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
 909
 910 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
 911
 912 extern int have_ptrace_getregset;
 913
 914 /* Search for the value with type MATCH in the auxv vector with
 915    entries of length WORDSIZE bytes.  If found, store the value in
 916    *VALP and return 1.  If not found or if there is an error, return
 917    0.  */
 918
 919 int linux_get_auxv (int wordsize, CORE_ADDR match,
 920                     CORE_ADDR *valp);
 921
 922 /* Fetch the AT_ENTRY entry from the auxv vector, where entries are length
 923    WORDSIZE.  If no entry was found, return zero.  */
 924
 925 CORE_ADDR linux_get_at_entry (int wordsize);
 926
 927 /* Fetch the AT_HWCAP entry from the auxv vector, where entries are length
 928    WORDSIZE.  If no entry was found, return zero.  */
 929
 930 CORE_ADDR linux_get_hwcap (int wordsize);
 931
 932 /* Fetch the AT_HWCAP2 entry from the auxv vector, where entries are length
 933    WORDSIZE.  If no entry was found, return zero.  */
 934
 935 CORE_ADDR linux_get_hwcap2 (int wordsize);
 936
 937 #endif /* GDBSERVER_LINUX_LOW_H */