gdb/linux-nat.h

   1 /* Native debugging support for GNU/Linux (LWP layer).
   2
   3    Copyright (C) 2000-2022 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 can_async_p () override;
  86
  87   bool supports_non_stop () override;
  88   bool always_non_stop_p () override;
  89
  90   void async (int) 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                    int *target_errno) override;
 105
 106   gdb::optional<std::string>
 107     fileio_readlink (struct inferior *inf,
 108                      const char *filename,
 109                      int *target_errno) override;
 110
 111   int fileio_unlink (struct inferior *inf,
 112                      const char *filename,
 113                      int *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   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   std::vector<static_tracepoint_marker>
 133     static_tracepoint_markers_by_strid (const char *id) override;
 134
 135   /* Methods that are meant to overridden by the concrete
 136      arch-specific target instance.  */
 137
 138   virtual void low_resume (ptid_t ptid, int step, enum gdb_signal sig)
 139   { inf_ptrace_target::resume (ptid, step, sig); }
 140
 141   virtual bool low_stopped_by_watchpoint ()
 142   { return false; }
 143
 144   virtual bool low_stopped_data_address (CORE_ADDR *addr_p)
 145   { return false; }
 146
 147   /* The method to call, if any, when a new thread is attached.  */
 148   virtual void low_new_thread (struct lwp_info *)
 149   {}
 150
 151   /* The method to call, if any, when a thread is destroyed.  */
 152   virtual void low_delete_thread (struct arch_lwp_info *lp)
 153   {
 154     gdb_assert (lp == NULL);
 155   }
 156
 157   /* The method to call, if any, when a new fork is attached.  */
 158   virtual void low_new_fork (struct lwp_info *parent, pid_t child_pid)
 159   {}
 160
 161   /* The method to call, if any, when a new clone event is detected.  */
 162   virtual void low_new_clone (struct lwp_info *parent, pid_t child_lwp)
 163   {}
 164
 165   /* The method to call, if any, when a process is no longer
 166      attached.  */
 167   virtual void low_forget_process (pid_t pid)
 168   {}
 169
 170   /* Hook to call prior to resuming a thread.  */
 171   virtual void low_prepare_to_resume (struct lwp_info *)
 172   {}
 173
 174   /* Convert a ptrace/host siginfo object, into/from the siginfo in
 175      the layout of the inferiors' architecture.  Returns true if any
 176      conversion was done; false otherwise, in which case the caller
 177      does a straight memcpy.  If DIRECTION is 1, then copy from INF to
 178      PTRACE.  If DIRECTION is 0, copy from PTRACE to INF.  */
 179   virtual bool low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf,
 180                                   int direction)
 181   { return false; }
 182
 183   /* SIGTRAP-like breakpoint status events recognizer.  The default
 184      recognizes SIGTRAP only.  */
 185   virtual bool low_status_is_event (int status);
 186
 187 protected:
 188
 189     void post_startup_inferior (ptid_t) override;
 190 };
 191
 192 /* The final/concrete instance.  */
 193 extern linux_nat_target *linux_target;
 194
 195 struct arch_lwp_info;
 196
 197 /* Structure describing an LWP.  */
 198
 199 struct lwp_info : intrusive_list_node<lwp_info>
 200 {
 201   lwp_info (ptid_t ptid)
 202     : ptid (ptid)
 203   {}
 204
 205   ~lwp_info ();
 206
 207   DISABLE_COPY_AND_ASSIGN (lwp_info);
 208
 209   /* The process id of the LWP.  This is a combination of the LWP id
 210      and overall process id.  */
 211   ptid_t ptid = null_ptid;
 212
 213   /* If this flag is set, we need to set the event request flags the
 214      next time we see this LWP stop.  */
 215   int must_set_ptrace_flags = 0;
 216
 217   /* Non-zero if we sent this LWP a SIGSTOP (but the LWP didn't report
 218      it back yet).  */
 219   int signalled = 0;
 220
 221   /* Non-zero if this LWP is stopped.  */
 222   int stopped = 0;
 223
 224   /* Non-zero if this LWP will be/has been resumed.  Note that an LWP
 225      can be marked both as stopped and resumed at the same time.  This
 226      happens if we try to resume an LWP that has a wait status
 227      pending.  We shouldn't let the LWP run until that wait status has
 228      been processed, but we should not report that wait status if GDB
 229      didn't try to let the LWP run.  */
 230   int resumed = 0;
 231
 232   /* The last resume GDB requested on this thread.  */
 233   resume_kind last_resume_kind = resume_continue;
 234
 235   /* If non-zero, a pending wait status.  */
 236   int status = 0;
 237
 238   /* When 'stopped' is set, this is where the lwp last stopped, with
 239      decr_pc_after_break already accounted for.  If the LWP is
 240      running and stepping, this is the address at which the lwp was
 241      resumed (that is, it's the previous stop PC).  If the LWP is
 242      running and not stepping, this is 0.  */
 243   CORE_ADDR stop_pc = 0;
 244
 245   /* Non-zero if we were stepping this LWP.  */
 246   int step = 0;
 247
 248   /* The reason the LWP last stopped, if we need to track it
 249      (breakpoint, watchpoint, etc.).  */
 250   target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 251
 252   /* On architectures where it is possible to know the data address of
 253      a triggered watchpoint, STOPPED_DATA_ADDRESS_P is non-zero, and
 254      STOPPED_DATA_ADDRESS contains such data address.  Otherwise,
 255      STOPPED_DATA_ADDRESS_P is false, and STOPPED_DATA_ADDRESS is
 256      undefined.  Only valid if STOPPED_BY_WATCHPOINT is true.  */
 257   int stopped_data_address_p = 0;
 258   CORE_ADDR stopped_data_address = 0;
 259
 260   /* Non-zero if we expect a duplicated SIGINT.  */
 261   int ignore_sigint = 0;
 262
 263   /* If WAITSTATUS->KIND != TARGET_WAITKIND_SPURIOUS, the waitstatus
 264      for this LWP's last event.  This may correspond to STATUS above,
 265      or to a local variable in lin_lwp_wait.  */
 266   struct target_waitstatus waitstatus;
 267
 268   /* Signal whether we are in a SYSCALL_ENTRY or
 269      in a SYSCALL_RETURN event.
 270      Values:
 271      - TARGET_WAITKIND_SYSCALL_ENTRY
 272      - TARGET_WAITKIND_SYSCALL_RETURN */
 273   enum target_waitkind syscall_state;
 274
 275   /* The processor core this LWP was last seen on.  */
 276   int core = -1;
 277
 278   /* Arch-specific additions.  */
 279   struct arch_lwp_info *arch_private = nullptr;
 280 };
 281
 282 /* lwp_info iterator and range types.  */
 283
 284 using lwp_info_iterator
 285   = reference_to_pointer_iterator<intrusive_list<lwp_info>::iterator>;
 286 using lwp_info_range = iterator_range<lwp_info_iterator>;
 287 using lwp_info_safe_range = basic_safe_range<lwp_info_range>;
 288
 289 /* Get an iterable range over all lwps.  */
 290
 291 lwp_info_range all_lwps ();
 292
 293 /* Same as the above, but safe against deletion while iterating.  */
 294
 295 lwp_info_safe_range all_lwps_safe ();
 296
 297 /* Does the current host support PTRACE_GETREGSET?  */
 298 extern enum tribool have_ptrace_getregset;
 299
 300 /* Called from the LWP layer to inform the thread_db layer that PARENT
 301    spawned CHILD.  Both LWPs are currently stopped.  This function
 302    does whatever is required to have the child LWP under the
 303    thread_db's control --- e.g., enabling event reporting.  Returns
 304    true on success, false if the process isn't using libpthread.  */
 305 extern int thread_db_notice_clone (ptid_t parent, ptid_t child);
 306
 307 /* Return the number of signals used by the threads library.  */
 308 extern unsigned int lin_thread_get_thread_signal_num (void);
 309
 310 /* Return the i-th signal used by the threads library.  */
 311 extern int lin_thread_get_thread_signal (unsigned int i);
 312
 313 /* Find process PID's pending signal set from /proc/pid/status.  */
 314 void linux_proc_pending_signals (int pid, sigset_t *pending,
 315                                  sigset_t *blocked, sigset_t *ignored);
 316
 317 /* For linux_stop_lwp see nat/linux-nat.h.  */
 318
 319 /* Stop all LWPs, synchronously.  (Any events that trigger while LWPs
 320    are being stopped are left pending.)  */
 321 extern void linux_stop_and_wait_all_lwps (void);
 322
 323 /* Set resumed LWPs running again, as they were before being stopped
 324    with linux_stop_and_wait_all_lwps.  (LWPS with pending events are
 325    left stopped.)  */
 326 extern void linux_unstop_all_lwps (void);
 327
 328 /* Update linux-nat internal state when changing from one fork
 329    to another.  */
 330 void linux_nat_switch_fork (ptid_t new_ptid);
 331
 332 /* Store the saved siginfo associated with PTID in *SIGINFO.
 333    Return 1 if it was retrieved successfully, 0 otherwise (*SIGINFO is
 334    uninitialized in such case).  */
 335 int linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo);
 336
 337 #endif /* LINUX_NAT_H */