gdb/linux-nat.h

   1 /* Native debugging support for GNU/Linux (LWP layer).
   2
   3    Copyright (C) 2000-2024 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 #ifndef LINUX_NAT_H
  21 #define LINUX_NAT_H
  22
  23 #include "nat/linux-nat.h"
  24 #include "inf-ptrace.h"
  25 #include "target.h"
  26 #include <signal.h>
  27
  28 /* A prototype generic GNU/Linux target.  A concrete instance should
  29    override it with local methods.  */
  30
  31 class linux_nat_target : public inf_ptrace_target
  32 {
  33 public:
  34   linux_nat_target ();
  35   ~linux_nat_target () override = 0;
  36
  37   thread_control_capabilities get_thread_control_capabilities () override
  38   { return tc_schedlock; }
  39
  40   void create_inferior (const char *, const std::string &,
  41                         char **, int) override;
  42
  43   void attach (const char *, int) override;
  44
  45   void detach (inferior *, int) override;
  46
  47   void resume (ptid_t, int, enum gdb_signal) override;
  48
  49   ptid_t wait (ptid_t, struct target_waitstatus *, target_wait_flags) override;
  50
  51   void pass_signals (gdb::array_view<const unsigned char>) override;
  52
  53   enum target_xfer_status xfer_partial (enum target_object object,
  54                                         const char *annex,
  55                                         gdb_byte *readbuf,
  56                                         const gdb_byte *writebuf,
  57                                         ULONGEST offset, ULONGEST len,
  58                                         ULONGEST *xfered_len) override;
  59
  60   void kill () override;
  61
  62   void mourn_inferior () override;
  63   bool thread_alive (ptid_t ptid) override;
  64
  65   void update_thread_list () override;
  66
  67   std::string pid_to_str (ptid_t) override;
  68
  69   const char *thread_name (struct thread_info *) override;
  70
  71   bool stopped_by_watchpoint () override;
  72
  73   bool stopped_data_address (CORE_ADDR *) override;
  74
  75   bool stopped_by_sw_breakpoint () override;
  76   bool supports_stopped_by_sw_breakpoint () override;
  77
  78   bool stopped_by_hw_breakpoint () override;
  79   bool supports_stopped_by_hw_breakpoint () override;
  80
  81   void thread_events (int) override;
  82
  83   bool supports_set_thread_options (gdb_thread_options options) override;
  84
  85   bool can_async_p () override;
  86
  87   bool supports_non_stop () override;
  88   bool always_non_stop_p () override;
  89
  90   void async (bool) override;
  91
  92   void stop (ptid_t) override;
  93
  94   bool supports_multi_process () override;
  95
  96   bool supports_disable_randomization () override;
  97
  98   int core_of_thread (ptid_t ptid) override;
  99
 100   bool filesystem_is_local () override;
 101
 102   int fileio_open (struct inferior *inf, const char *filename,
 103                    int flags, int mode, int warn_if_slow,
 104                    fileio_error *target_errno) override;
 105
 106   std::optional<std::string>
 107     fileio_readlink (struct inferior *inf,
 108                      const char *filename,
 109                      fileio_error *target_errno) override;
 110
 111   int fileio_unlink (struct inferior *inf,
 112                      const char *filename,
 113                      fileio_error *target_errno) override;
 114
 115   int insert_fork_catchpoint (int) override;
 116   int remove_fork_catchpoint (int) override;
 117   int insert_vfork_catchpoint (int) override;
 118   int remove_vfork_catchpoint (int) override;
 119
 120   int insert_exec_catchpoint (int) override;
 121   int remove_exec_catchpoint (int) override;
 122
 123   int set_syscall_catchpoint (int pid, bool needed, int any_count,
 124                               gdb::array_view<const int> syscall_counts) override;
 125
 126   const char *pid_to_exec_file (int pid) override;
 127
 128   void post_attach (int) override;
 129
 130   void follow_fork (inferior *, ptid_t, target_waitkind, bool, bool) override;
 131
 132   void follow_clone (ptid_t) override;
 133
 134   std::vector<static_tracepoint_marker>
 135     static_tracepoint_markers_by_strid (const char *id) override;
 136
 137   /* Methods that are meant to overridden by the concrete
 138      arch-specific target instance.  */
 139
 140   virtual void low_resume (ptid_t ptid, int step, enum gdb_signal sig)
 141   { inf_ptrace_target::resume (ptid, step, sig); }
 142
 143   virtual bool low_stopped_by_watchpoint ()
 144   { return false; }
 145
 146   virtual bool low_stopped_data_address (CORE_ADDR *addr_p)
 147   { return false; }
 148
 149   /* The method to call, if any, when a new thread is attached.  */
 150   virtual void low_new_thread (struct lwp_info *)
 151   {}
 152
 153   /* The method to call, if any, when a thread is destroyed.  */
 154   virtual void low_delete_thread (struct arch_lwp_info *lp)
 155   {
 156     gdb_assert (lp == NULL);
 157   }
 158
 159   /* The method to call, if any, when a new fork is attached.  */
 160   virtual void low_new_fork (struct lwp_info *parent, pid_t child_pid)
 161   {}
 162
 163   /* The method to call, if any, when a new clone event is detected.  */
 164   virtual void low_new_clone (struct lwp_info *parent, pid_t child_lwp)
 165   {}
 166
 167   /* The method to call, if any, when a process is no longer
 168      attached.  */
 169   virtual void low_forget_process (pid_t pid)
 170   {}
 171
 172   /* Hook to call prior to resuming a thread.  */
 173   virtual void low_prepare_to_resume (struct lwp_info *)
 174   {}
 175
 176   /* Convert a ptrace/host siginfo object, into/from the siginfo in
 177      the layout of the inferiors' architecture.  Returns true if any
 178      conversion was done; false otherwise, in which case the caller
 179      does a straight memcpy.  If DIRECTION is 1, then copy from INF to
 180      PTRACE.  If DIRECTION is 0, copy from PTRACE to INF.  */
 181   virtual bool low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf,
 182                                   int direction)
 183   { return false; }
 184
 185   /* SIGTRAP-like breakpoint status events recognizer.  The default
 186      recognizes SIGTRAP only.  */
 187   virtual bool low_status_is_event (int status);
 188
 189 protected:
 190
 191     void post_startup_inferior (ptid_t) override;
 192 };
 193
 194 /* The final/concrete instance.  */
 195 extern linux_nat_target *linux_target;
 196
 197 struct arch_lwp_info;
 198
 199 /* Structure describing an LWP.  */
 200
 201 struct lwp_info : intrusive_list_node<lwp_info>
 202 {
 203   lwp_info (ptid_t ptid)
 204     : ptid (ptid)
 205   {}
 206
 207   ~lwp_info ();
 208
 209   DISABLE_COPY_AND_ASSIGN (lwp_info);
 210
 211   /* The process id of the LWP.  This is a combination of the LWP id
 212      and overall process id.  */
 213   ptid_t ptid = null_ptid;
 214
 215   /* If this flag is set, we need to set the event request flags the
 216      next time we see this LWP stop.  */
 217   int must_set_ptrace_flags = 0;
 218
 219   /* Non-zero if we sent this LWP a SIGSTOP (but the LWP didn't report
 220      it back yet).  */
 221   int signalled = 0;
 222
 223   /* Non-zero if this LWP is stopped.  */
 224   int stopped = 0;
 225
 226   /* Non-zero if this LWP will be/has been resumed.  Note that an LWP
 227      can be marked both as stopped and resumed at the same time.  This
 228      happens if we try to resume an LWP that has a wait status
 229      pending.  We shouldn't let the LWP run until that wait status has
 230      been processed, but we should not report that wait status if GDB
 231      didn't try to let the LWP run.  */
 232   int resumed = 0;
 233
 234   /* The last resume GDB requested on this thread.  */
 235   resume_kind last_resume_kind = resume_continue;
 236
 237   /* If non-zero, a pending wait status.  A pending process exit is
 238      recorded in WAITSTATUS, because W_EXITCODE(0,0) happens to be
 239      0.  */
 240   int status = 0;
 241
 242   /* When 'stopped' is set, this is where the lwp last stopped, with
 243      decr_pc_after_break already accounted for.  If the LWP is
 244      running and stepping, this is the address at which the lwp was
 245      resumed (that is, it's the previous stop PC).  If the LWP is
 246      running and not stepping, this is 0.  */
 247   CORE_ADDR stop_pc = 0;
 248
 249   /* Non-zero if we were stepping this LWP.  */
 250   int step = 0;
 251
 252   /* The reason the LWP last stopped, if we need to track it
 253      (breakpoint, watchpoint, etc.).  */
 254   target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 255
 256   /* On architectures where it is possible to know the data address of
 257      a triggered watchpoint, STOPPED_DATA_ADDRESS_P is non-zero, and
 258      STOPPED_DATA_ADDRESS contains such data address.  Otherwise,
 259      STOPPED_DATA_ADDRESS_P is false, and STOPPED_DATA_ADDRESS is
 260      undefined.  Only valid if STOPPED_BY_WATCHPOINT is true.  */
 261   int stopped_data_address_p = 0;
 262   CORE_ADDR stopped_data_address = 0;
 263
 264   /* Non-zero if we expect a duplicated SIGINT.  */
 265   int ignore_sigint = 0;
 266
 267   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 268      this LWP's last event.  This usually corresponds to STATUS above,
 269      however because W_EXITCODE(0,0) happens to be 0, a process exit
 270      will be recorded here, while 'status == 0' is ambiguous.  */
 271   struct target_waitstatus waitstatus;
 272
 273   /* Signal whether we are in a SYSCALL_ENTRY or
 274      in a SYSCALL_RETURN event.
 275      Values:
 276      - TARGET_WAITKIND_SYSCALL_ENTRY
 277      - TARGET_WAITKIND_SYSCALL_RETURN */
 278   enum target_waitkind syscall_state;
 279
 280   /* The processor core this LWP was last seen on.  */
 281   int core = -1;
 282
 283   /* Arch-specific additions.  */
 284   struct arch_lwp_info *arch_private = nullptr;
 285 };
 286
 287 /* lwp_info iterator and range types.  */
 288
 289 using lwp_info_iterator
 290   = reference_to_pointer_iterator<intrusive_list<lwp_info>::iterator>;
 291 using lwp_info_range = iterator_range<lwp_info_iterator>;
 292 using lwp_info_safe_range = basic_safe_range<lwp_info_range>;
 293
 294 /* Get an iterable range over all lwps.  */
 295
 296 lwp_info_range all_lwps ();
 297
 298 /* Same as the above, but safe against deletion while iterating.  */
 299
 300 lwp_info_safe_range all_lwps_safe ();
 301
 302 /* Does the current host support PTRACE_GETREGSET?  */
 303 extern enum tribool have_ptrace_getregset;
 304
 305 /* Called from the LWP layer to inform the thread_db layer that PARENT
 306    spawned CHILD.  Both LWPs are currently stopped.  This function
 307    does whatever is required to have the child LWP under the
 308    thread_db's control --- e.g., enabling event reporting.  Returns
 309    true on success, false if the process isn't using libpthread.  */
 310 extern int thread_db_notice_clone (ptid_t parent, ptid_t child);
 311
 312 /* Return the number of signals used by the threads library.  */
 313 extern unsigned int lin_thread_get_thread_signal_num (void);
 314
 315 /* Return the i-th signal used by the threads library.  */
 316 extern int lin_thread_get_thread_signal (unsigned int i);
 317
 318 /* Find process PID's pending signal set from /proc/pid/status.  */
 319 void linux_proc_pending_signals (int pid, sigset_t *pending,
 320                                  sigset_t *blocked, sigset_t *ignored);
 321
 322 /* For linux_stop_lwp see nat/linux-nat.h.  */
 323
 324 /* Stop all LWPs, synchronously.  (Any events that trigger while LWPs
 325    are being stopped are left pending.)  */
 326 extern void linux_stop_and_wait_all_lwps (void);
 327
 328 /* Set resumed LWPs running again, as they were before being stopped
 329    with linux_stop_and_wait_all_lwps.  (LWPS with pending events are
 330    left stopped.)  */
 331 extern void linux_unstop_all_lwps (void);
 332
 333 /* Update linux-nat internal state when changing from one fork
 334    to another.  */
 335 void linux_nat_switch_fork (ptid_t new_ptid);
 336
 337 /* Store the saved siginfo associated with PTID in *SIGINFO.
 338    Return true if it was retrieved successfully, false otherwise (*SIGINFO is
 339    uninitialized in such case).  */
 340 bool linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo);
 341
 342 #endif /* LINUX_NAT_H */