gdb/linux-nat.h

   1 /* Native debugging support for GNU/Linux (LWP layer).
   2
   3    Copyright (C) 2000-2023 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   struct address_space *thread_address_space (ptid_t) override;
  72
  73   bool stopped_by_watchpoint () override;
  74
  75   bool stopped_data_address (CORE_ADDR *) override;
  76
  77   bool stopped_by_sw_breakpoint () override;
  78   bool supports_stopped_by_sw_breakpoint () override;
  79
  80   bool stopped_by_hw_breakpoint () override;
  81   bool supports_stopped_by_hw_breakpoint () override;
  82
  83   void thread_events (int) override;
  84
  85   bool supports_set_thread_options (gdb_thread_options options) override;
  86
  87   bool can_async_p () override;
  88
  89   bool supports_non_stop () override;
  90   bool always_non_stop_p () override;
  91
  92   void async (bool) override;
  93
  94   void stop (ptid_t) override;
  95
  96   bool supports_multi_process () override;
  97
  98   bool supports_disable_randomization () override;
  99
 100   int core_of_thread (ptid_t ptid) override;
 101
 102   bool filesystem_is_local () override;
 103
 104   int fileio_open (struct inferior *inf, const char *filename,
 105                    int flags, int mode, int warn_if_slow,
 106                    fileio_error *target_errno) override;
 107
 108   gdb::optional<std::string>
 109     fileio_readlink (struct inferior *inf,
 110                      const char *filename,
 111                      fileio_error *target_errno) override;
 112
 113   int fileio_unlink (struct inferior *inf,
 114                      const char *filename,
 115                      fileio_error *target_errno) override;
 116
 117   int insert_fork_catchpoint (int) override;
 118   int remove_fork_catchpoint (int) override;
 119   int insert_vfork_catchpoint (int) override;
 120   int remove_vfork_catchpoint (int) override;
 121
 122   int insert_exec_catchpoint (int) override;
 123   int remove_exec_catchpoint (int) override;
 124
 125   int set_syscall_catchpoint (int pid, bool needed, int any_count,
 126                               gdb::array_view<const int> syscall_counts) override;
 127
 128   const char *pid_to_exec_file (int pid) override;
 129
 130   void post_attach (int) override;
 131
 132   void follow_fork (inferior *, ptid_t, target_waitkind, bool, bool) override;
 133
 134   void follow_clone (ptid_t) override;
 135
 136   std::vector<static_tracepoint_marker>
 137     static_tracepoint_markers_by_strid (const char *id) override;
 138
 139   /* Methods that are meant to overridden by the concrete
 140      arch-specific target instance.  */
 141
 142   virtual void low_resume (ptid_t ptid, int step, enum gdb_signal sig)
 143   { inf_ptrace_target::resume (ptid, step, sig); }
 144
 145   virtual bool low_stopped_by_watchpoint ()
 146   { return false; }
 147
 148   virtual bool low_stopped_data_address (CORE_ADDR *addr_p)
 149   { return false; }
 150
 151   /* The method to call, if any, when a new thread is attached.  */
 152   virtual void low_new_thread (struct lwp_info *)
 153   {}
 154
 155   /* The method to call, if any, when a thread is destroyed.  */
 156   virtual void low_delete_thread (struct arch_lwp_info *lp)
 157   {
 158     gdb_assert (lp == NULL);
 159   }
 160
 161   /* The method to call, if any, when a new fork is attached.  */
 162   virtual void low_new_fork (struct lwp_info *parent, pid_t child_pid)
 163   {}
 164
 165   /* The method to call, if any, when a new clone event is detected.  */
 166   virtual void low_new_clone (struct lwp_info *parent, pid_t child_lwp)
 167   {}
 168
 169   /* The method to call, if any, when a process is no longer
 170      attached.  */
 171   virtual void low_forget_process (pid_t pid)
 172   {}
 173
 174   /* Hook to call prior to resuming a thread.  */
 175   virtual void low_prepare_to_resume (struct lwp_info *)
 176   {}
 177
 178   /* Convert a ptrace/host siginfo object, into/from the siginfo in
 179      the layout of the inferiors' architecture.  Returns true if any
 180      conversion was done; false otherwise, in which case the caller
 181      does a straight memcpy.  If DIRECTION is 1, then copy from INF to
 182      PTRACE.  If DIRECTION is 0, copy from PTRACE to INF.  */
 183   virtual bool low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf,
 184                                   int direction)
 185   { return false; }
 186
 187   /* SIGTRAP-like breakpoint status events recognizer.  The default
 188      recognizes SIGTRAP only.  */
 189   virtual bool low_status_is_event (int status);
 190
 191 protected:
 192
 193     void post_startup_inferior (ptid_t) override;
 194 };
 195
 196 /* The final/concrete instance.  */
 197 extern linux_nat_target *linux_target;
 198
 199 struct arch_lwp_info;
 200
 201 /* Structure describing an LWP.  */
 202
 203 struct lwp_info : intrusive_list_node<lwp_info>
 204 {
 205   lwp_info (ptid_t ptid)
 206     : ptid (ptid)
 207   {}
 208
 209   ~lwp_info ();
 210
 211   DISABLE_COPY_AND_ASSIGN (lwp_info);
 212
 213   /* The process id of the LWP.  This is a combination of the LWP id
 214      and overall process id.  */
 215   ptid_t ptid = null_ptid;
 216
 217   /* If this flag is set, we need to set the event request flags the
 218      next time we see this LWP stop.  */
 219   int must_set_ptrace_flags = 0;
 220
 221   /* Non-zero if we sent this LWP a SIGSTOP (but the LWP didn't report
 222      it back yet).  */
 223   int signalled = 0;
 224
 225   /* Non-zero if this LWP is stopped.  */
 226   int stopped = 0;
 227
 228   /* Non-zero if this LWP will be/has been resumed.  Note that an LWP
 229      can be marked both as stopped and resumed at the same time.  This
 230      happens if we try to resume an LWP that has a wait status
 231      pending.  We shouldn't let the LWP run until that wait status has
 232      been processed, but we should not report that wait status if GDB
 233      didn't try to let the LWP run.  */
 234   int resumed = 0;
 235
 236   /* The last resume GDB requested on this thread.  */
 237   resume_kind last_resume_kind = resume_continue;
 238
 239   /* If non-zero, a pending wait status.  A pending process exit is
 240      recorded in WAITSTATUS, because W_EXITCODE(0,0) happens to be
 241      0.  */
 242   int status = 0;
 243
 244   /* When 'stopped' is set, this is where the lwp last stopped, with
 245      decr_pc_after_break already accounted for.  If the LWP is
 246      running and stepping, this is the address at which the lwp was
 247      resumed (that is, it's the previous stop PC).  If the LWP is
 248      running and not stepping, this is 0.  */
 249   CORE_ADDR stop_pc = 0;
 250
 251   /* Non-zero if we were stepping this LWP.  */
 252   int step = 0;
 253
 254   /* The reason the LWP last stopped, if we need to track it
 255      (breakpoint, watchpoint, etc.).  */
 256   target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 257
 258   /* On architectures where it is possible to know the data address of
 259      a triggered watchpoint, STOPPED_DATA_ADDRESS_P is non-zero, and
 260      STOPPED_DATA_ADDRESS contains such data address.  Otherwise,
 261      STOPPED_DATA_ADDRESS_P is false, and STOPPED_DATA_ADDRESS is
 262      undefined.  Only valid if STOPPED_BY_WATCHPOINT is true.  */
 263   int stopped_data_address_p = 0;
 264   CORE_ADDR stopped_data_address = 0;
 265
 266   /* Non-zero if we expect a duplicated SIGINT.  */
 267   int ignore_sigint = 0;
 268
 269   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 270      this LWP's last event.  This usually corresponds to STATUS above,
 271      however because W_EXITCODE(0,0) happens to be 0, a process exit
 272      will be recorded here, while 'status == 0' is ambiguous.  */
 273   struct target_waitstatus waitstatus;
 274
 275   /* Signal whether we are in a SYSCALL_ENTRY or
 276      in a SYSCALL_RETURN event.
 277      Values:
 278      - TARGET_WAITKIND_SYSCALL_ENTRY
 279      - TARGET_WAITKIND_SYSCALL_RETURN */
 280   enum target_waitkind syscall_state;
 281
 282   /* The processor core this LWP was last seen on.  */
 283   int core = -1;
 284
 285   /* Arch-specific additions.  */
 286   struct arch_lwp_info *arch_private = nullptr;
 287 };
 288
 289 /* lwp_info iterator and range types.  */
 290
 291 using lwp_info_iterator
 292   = reference_to_pointer_iterator<intrusive_list<lwp_info>::iterator>;
 293 using lwp_info_range = iterator_range<lwp_info_iterator>;
 294 using lwp_info_safe_range = basic_safe_range<lwp_info_range>;
 295
 296 /* Get an iterable range over all lwps.  */
 297
 298 lwp_info_range all_lwps ();
 299
 300 /* Same as the above, but safe against deletion while iterating.  */
 301
 302 lwp_info_safe_range all_lwps_safe ();
 303
 304 /* Does the current host support PTRACE_GETREGSET?  */
 305 extern enum tribool have_ptrace_getregset;
 306
 307 /* Called from the LWP layer to inform the thread_db layer that PARENT
 308    spawned CHILD.  Both LWPs are currently stopped.  This function
 309    does whatever is required to have the child LWP under the
 310    thread_db's control --- e.g., enabling event reporting.  Returns
 311    true on success, false if the process isn't using libpthread.  */
 312 extern int thread_db_notice_clone (ptid_t parent, ptid_t child);
 313
 314 /* Return the number of signals used by the threads library.  */
 315 extern unsigned int lin_thread_get_thread_signal_num (void);
 316
 317 /* Return the i-th signal used by the threads library.  */
 318 extern int lin_thread_get_thread_signal (unsigned int i);
 319
 320 /* Find process PID's pending signal set from /proc/pid/status.  */
 321 void linux_proc_pending_signals (int pid, sigset_t *pending,
 322                                  sigset_t *blocked, sigset_t *ignored);
 323
 324 /* For linux_stop_lwp see nat/linux-nat.h.  */
 325
 326 /* Stop all LWPs, synchronously.  (Any events that trigger while LWPs
 327    are being stopped are left pending.)  */
 328 extern void linux_stop_and_wait_all_lwps (void);
 329
 330 /* Set resumed LWPs running again, as they were before being stopped
 331    with linux_stop_and_wait_all_lwps.  (LWPS with pending events are
 332    left stopped.)  */
 333 extern void linux_unstop_all_lwps (void);
 334
 335 /* Update linux-nat internal state when changing from one fork
 336    to another.  */
 337 void linux_nat_switch_fork (ptid_t new_ptid);
 338
 339 /* Store the saved siginfo associated with PTID in *SIGINFO.
 340    Return true if it was retrieved successfully, false otherwise (*SIGINFO is
 341    uninitialized in such case).  */
 342 bool linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo);
 343
 344 #endif /* LINUX_NAT_H */