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 (bool) 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 we have a new (from run/attach,
 168      not fork) process to debug.  The process is ptrace-stopped when
 169      this is called.  */
 170   virtual void low_init_process (pid_t pid)
 171   {}
 172
 173   /* The method to call, if any, when a process is no longer
 174      attached.  */
 175   virtual void low_forget_process (pid_t pid)
 176   {}
 177
 178   /* Hook to call prior to resuming a thread.  */
 179   virtual void low_prepare_to_resume (struct lwp_info *)
 180   {}
 181
 182   /* Convert a ptrace/host siginfo object, into/from the siginfo in
 183      the layout of the inferiors' architecture.  Returns true if any
 184      conversion was done; false otherwise, in which case the caller
 185      does a straight memcpy.  If DIRECTION is 1, then copy from INF to
 186      PTRACE.  If DIRECTION is 0, copy from PTRACE to INF.  */
 187   virtual bool low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf,
 188                                   int direction)
 189   { return false; }
 190
 191   /* SIGTRAP-like breakpoint status events recognizer.  The default
 192      recognizes SIGTRAP only.  */
 193   virtual bool low_status_is_event (int status);
 194
 195 protected:
 196
 197     void post_startup_inferior (ptid_t) override;
 198 };
 199
 200 /* The final/concrete instance.  */
 201 extern linux_nat_target *linux_target;
 202
 203 struct arch_lwp_info;
 204
 205 /* Structure describing an LWP.  */
 206
 207 struct lwp_info : intrusive_list_node<lwp_info>
 208 {
 209   lwp_info (ptid_t ptid)
 210     : ptid (ptid)
 211   {}
 212
 213   ~lwp_info ();
 214
 215   DISABLE_COPY_AND_ASSIGN (lwp_info);
 216
 217   /* The process id of the LWP.  This is a combination of the LWP id
 218      and overall process id.  */
 219   ptid_t ptid = null_ptid;
 220
 221   /* If this flag is set, we need to set the event request flags the
 222      next time we see this LWP stop.  */
 223   int must_set_ptrace_flags = 0;
 224
 225   /* Non-zero if we sent this LWP a SIGSTOP (but the LWP didn't report
 226      it back yet).  */
 227   int signalled = 0;
 228
 229   /* Non-zero if this LWP is stopped.  */
 230   int stopped = 0;
 231
 232   /* Non-zero if this LWP will be/has been resumed.  Note that an LWP
 233      can be marked both as stopped and resumed at the same time.  This
 234      happens if we try to resume an LWP that has a wait status
 235      pending.  We shouldn't let the LWP run until that wait status has
 236      been processed, but we should not report that wait status if GDB
 237      didn't try to let the LWP run.  */
 238   int resumed = 0;
 239
 240   /* The last resume GDB requested on this thread.  */
 241   resume_kind last_resume_kind = resume_continue;
 242
 243   /* If non-zero, a pending wait status.  A pending process exit is
 244      recorded in WAITSTATUS, because W_EXITCODE(0,0) happens to be
 245      0.  */
 246   int status = 0;
 247
 248   /* When 'stopped' is set, this is where the lwp last stopped, with
 249      decr_pc_after_break already accounted for.  If the LWP is
 250      running and stepping, this is the address at which the lwp was
 251      resumed (that is, it's the previous stop PC).  If the LWP is
 252      running and not stepping, this is 0.  */
 253   CORE_ADDR stop_pc = 0;
 254
 255   /* Non-zero if we were stepping this LWP.  */
 256   int step = 0;
 257
 258   /* The reason the LWP last stopped, if we need to track it
 259      (breakpoint, watchpoint, etc.).  */
 260   target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 261
 262   /* On architectures where it is possible to know the data address of
 263      a triggered watchpoint, STOPPED_DATA_ADDRESS_P is non-zero, and
 264      STOPPED_DATA_ADDRESS contains such data address.  Otherwise,
 265      STOPPED_DATA_ADDRESS_P is false, and STOPPED_DATA_ADDRESS is
 266      undefined.  Only valid if STOPPED_BY_WATCHPOINT is true.  */
 267   int stopped_data_address_p = 0;
 268   CORE_ADDR stopped_data_address = 0;
 269
 270   /* Non-zero if we expect a duplicated SIGINT.  */
 271   int ignore_sigint = 0;
 272
 273   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 274      this LWP's last event.  This usually corresponds to STATUS above,
 275      however because W_EXITCODE(0,0) happens to be 0, a process exit
 276      will be recorded here, while 'status == 0' is ambiguous.  */
 277   struct target_waitstatus waitstatus;
 278
 279   /* Signal whether we are in a SYSCALL_ENTRY or
 280      in a SYSCALL_RETURN event.
 281      Values:
 282      - TARGET_WAITKIND_SYSCALL_ENTRY
 283      - TARGET_WAITKIND_SYSCALL_RETURN */
 284   enum target_waitkind syscall_state;
 285
 286   /* The processor core this LWP was last seen on.  */
 287   int core = -1;
 288
 289   /* Arch-specific additions.  */
 290   struct arch_lwp_info *arch_private = nullptr;
 291 };
 292
 293 /* lwp_info iterator and range types.  */
 294
 295 using lwp_info_iterator
 296   = reference_to_pointer_iterator<intrusive_list<lwp_info>::iterator>;
 297 using lwp_info_range = iterator_range<lwp_info_iterator>;
 298 using lwp_info_safe_range = basic_safe_range<lwp_info_range>;
 299
 300 /* Get an iterable range over all lwps.  */
 301
 302 lwp_info_range all_lwps ();
 303
 304 /* Same as the above, but safe against deletion while iterating.  */
 305
 306 lwp_info_safe_range all_lwps_safe ();
 307
 308 /* Called from the LWP layer to inform the thread_db layer that PARENT
 309    spawned CHILD.  Both LWPs are currently stopped.  This function
 310    does whatever is required to have the child LWP under the
 311    thread_db's control --- e.g., enabling event reporting.  Returns
 312    true on success, false if the process isn't using libpthread.  */
 313 extern int thread_db_notice_clone (ptid_t parent, ptid_t child);
 314
 315 /* Return the number of signals used by the threads library.  */
 316 extern unsigned int lin_thread_get_thread_signal_num (void);
 317
 318 /* Return the i-th signal used by the threads library.  */
 319 extern int lin_thread_get_thread_signal (unsigned int i);
 320
 321 /* Find process PID's pending signal set from /proc/pid/status.  */
 322 void linux_proc_pending_signals (int pid, sigset_t *pending,
 323                                  sigset_t *blocked, sigset_t *ignored);
 324
 325 /* For linux_stop_lwp see nat/linux-nat.h.  */
 326
 327 /* Stop all LWPs, synchronously.  (Any events that trigger while LWPs
 328    are being stopped are left pending.)  */
 329 extern void linux_stop_and_wait_all_lwps (void);
 330
 331 /* Set resumed LWPs running again, as they were before being stopped
 332    with linux_stop_and_wait_all_lwps.  (LWPS with pending events are
 333    left stopped.)  */
 334 extern void linux_unstop_all_lwps (void);
 335
 336 /* Update linux-nat internal state when changing from one fork
 337    to another.  */
 338 void linux_nat_switch_fork (ptid_t new_ptid);
 339
 340 /* Store the saved siginfo associated with PTID in *SIGINFO.
 341    Return true if it was retrieved successfully, false otherwise (*SIGINFO is
 342    uninitialized in such case).  */
 343 bool linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo);
 344
 345 #endif /* LINUX_NAT_H */