gdb/linux-nat.h

   1 /* Native debugging support for GNU/Linux (LWP layer).
   2
   3    Copyright (C) 2000-2020 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 *, int) 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   bool is_async_p () override;
  87
  88   bool supports_non_stop () override;
  89   bool always_non_stop_p () override;
  90
  91   int async_wait_fd () override;
  92   void async (int) override;
  93
  94   void close () override;
  95
  96   void stop (ptid_t) override;
  97
  98   bool supports_multi_process () override;
  99
 100   bool supports_disable_randomization () override;
 101
 102   int core_of_thread (ptid_t ptid) override;
 103
 104   bool filesystem_is_local () override;
 105
 106   int fileio_open (struct inferior *inf, const char *filename,
 107                    int flags, int mode, int warn_if_slow,
 108                    int *target_errno) override;
 109
 110   gdb::optional<std::string>
 111     fileio_readlink (struct inferior *inf,
 112                      const char *filename,
 113                      int *target_errno) override;
 114
 115   int fileio_unlink (struct inferior *inf,
 116                      const char *filename,
 117                      int *target_errno) override;
 118
 119   int insert_fork_catchpoint (int) override;
 120   int remove_fork_catchpoint (int) override;
 121   int insert_vfork_catchpoint (int) override;
 122   int remove_vfork_catchpoint (int) override;
 123
 124   int insert_exec_catchpoint (int) override;
 125   int remove_exec_catchpoint (int) override;
 126
 127   int set_syscall_catchpoint (int pid, bool needed, int any_count,
 128                               gdb::array_view<const int> syscall_counts) override;
 129
 130   char *pid_to_exec_file (int pid) override;
 131
 132   void post_startup_inferior (ptid_t) override;
 133
 134   void post_attach (int) override;
 135
 136   int follow_fork (int, int) override;
 137
 138   std::vector<static_tracepoint_marker>
 139     static_tracepoint_markers_by_strid (const char *id) override;
 140
 141   /* Methods that are meant to overridden by the concrete
 142      arch-specific target instance.  */
 143
 144   virtual void low_resume (ptid_t ptid, int step, enum gdb_signal sig)
 145   { inf_ptrace_target::resume (ptid, step, sig); }
 146
 147   virtual bool low_stopped_by_watchpoint ()
 148   { return false; }
 149
 150   virtual bool low_stopped_data_address (CORE_ADDR *addr_p)
 151   { return false; }
 152
 153   /* The method to call, if any, when a new thread is attached.  */
 154   virtual void low_new_thread (struct lwp_info *)
 155   {}
 156
 157   /* The method to call, if any, when a thread is destroyed.  */
 158   virtual void low_delete_thread (struct arch_lwp_info *lp)
 159   {
 160     gdb_assert (lp == NULL);
 161   }
 162
 163   /* The method to call, if any, when a new fork is attached.  */
 164   virtual void low_new_fork (struct lwp_info *parent, pid_t child_pid)
 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
 190 /* The final/concrete instance.  */
 191 extern linux_nat_target *linux_target;
 192
 193 struct arch_lwp_info;
 194
 195 /* Structure describing an LWP.  This is public only for the purposes
 196    of ALL_LWPS; target-specific code should generally not access it
 197    directly.  */
 198
 199 struct lwp_info
 200 {
 201   /* The process id of the LWP.  This is a combination of the LWP id
 202      and overall process id.  */
 203   ptid_t ptid;
 204
 205   /* If this flag is set, we need to set the event request flags the
 206      next time we see this LWP stop.  */
 207   int must_set_ptrace_flags;
 208
 209   /* Non-zero if we sent this LWP a SIGSTOP (but the LWP didn't report
 210      it back yet).  */
 211   int signalled;
 212
 213   /* Non-zero if this LWP is stopped.  */
 214   int stopped;
 215
 216   /* Non-zero if this LWP will be/has been resumed.  Note that an LWP
 217      can be marked both as stopped and resumed at the same time.  This
 218      happens if we try to resume an LWP that has a wait status
 219      pending.  We shouldn't let the LWP run until that wait status has
 220      been processed, but we should not report that wait status if GDB
 221      didn't try to let the LWP run.  */
 222   int resumed;
 223
 224   /* The last resume GDB requested on this thread.  */
 225   enum resume_kind last_resume_kind;
 226
 227   /* If non-zero, a pending wait status.  */
 228   int status;
 229
 230   /* When 'stopped' is set, this is where the lwp last stopped, with
 231      decr_pc_after_break already accounted for.  If the LWP is
 232      running, and stepping, this is the address at which the lwp was
 233      resumed (that is, it's the previous stop PC).  If the LWP is
 234      running and not stepping, this is 0.  */
 235   CORE_ADDR stop_pc;
 236
 237   /* Non-zero if we were stepping this LWP.  */
 238   int step;
 239
 240   /* The reason the LWP last stopped, if we need to track it
 241      (breakpoint, watchpoint, etc.)  */
 242   enum target_stop_reason stop_reason;
 243
 244   /* On architectures where it is possible to know the data address of
 245      a triggered watchpoint, STOPPED_DATA_ADDRESS_P is non-zero, and
 246      STOPPED_DATA_ADDRESS contains such data address.  Otherwise,
 247      STOPPED_DATA_ADDRESS_P is false, and STOPPED_DATA_ADDRESS is
 248      undefined.  Only valid if STOPPED_BY_WATCHPOINT is true.  */
 249   int stopped_data_address_p;
 250   CORE_ADDR stopped_data_address;
 251
 252   /* Non-zero if we expect a duplicated SIGINT.  */
 253   int ignore_sigint;
 254
 255   /* If WAITSTATUS->KIND != TARGET_WAITKIND_SPURIOUS, the waitstatus
 256      for this LWP's last event.  This may correspond to STATUS above,
 257      or to a local variable in lin_lwp_wait.  */
 258   struct target_waitstatus waitstatus;
 259
 260   /* Signal whether we are in a SYSCALL_ENTRY or
 261      in a SYSCALL_RETURN event.
 262      Values:
 263      - TARGET_WAITKIND_SYSCALL_ENTRY
 264      - TARGET_WAITKIND_SYSCALL_RETURN */
 265   enum target_waitkind syscall_state;
 266
 267   /* The processor core this LWP was last seen on.  */
 268   int core;
 269
 270   /* Arch-specific additions.  */
 271   struct arch_lwp_info *arch_private;
 272
 273   /* Previous and next pointers in doubly-linked list of known LWPs,
 274      sorted by reverse creation order.  */
 275   struct lwp_info *prev;
 276   struct lwp_info *next;
 277 };
 278
 279 /* The global list of LWPs, for ALL_LWPS.  Unlike the threads list,
 280    there is always at least one LWP on the list while the GNU/Linux
 281    native target is active.  */
 282 extern struct lwp_info *lwp_list;
 283
 284 /* Does the current host support PTRACE_GETREGSET?  */
 285 extern enum tribool have_ptrace_getregset;
 286
 287 /* Iterate over each active thread (light-weight process).  */
 288 #define ALL_LWPS(LP)                                                    \
 289   for ((LP) = lwp_list;                                                 \
 290        (LP) != NULL;                                                    \
 291        (LP) = (LP)->next)
 292
 293 /* Attempt to initialize libthread_db.  */
 294 void check_for_thread_db (void);
 295
 296 /* Called from the LWP layer to inform the thread_db layer that PARENT
 297    spawned CHILD.  Both LWPs are currently stopped.  This function
 298    does whatever is required to have the child LWP under the
 299    thread_db's control --- e.g., enabling event reporting.  Returns
 300    true on success, false if the process isn't using libpthread.  */
 301 extern int thread_db_notice_clone (ptid_t parent, ptid_t child);
 302
 303 /* Return the set of signals used by the threads library.  */
 304 extern void lin_thread_get_thread_signals (sigset_t *mask);
 305
 306 /* Find process PID's pending signal set from /proc/pid/status.  */
 307 void linux_proc_pending_signals (int pid, sigset_t *pending,
 308                                  sigset_t *blocked, sigset_t *ignored);
 309
 310 /* For linux_stop_lwp see nat/linux-nat.h.  */
 311
 312 /* Stop all LWPs, synchronously.  (Any events that trigger while LWPs
 313    are being stopped are left pending.)  */
 314 extern void linux_stop_and_wait_all_lwps (void);
 315
 316 /* Set resumed LWPs running again, as they were before being stopped
 317    with linux_stop_and_wait_all_lwps.  (LWPS with pending events are
 318    left stopped.)  */
 319 extern void linux_unstop_all_lwps (void);
 320
 321 /* Update linux-nat internal state when changing from one fork
 322    to another.  */
 323 void linux_nat_switch_fork (ptid_t new_ptid);
 324
 325 /* Store the saved siginfo associated with PTID in *SIGINFO.
 326    Return 1 if it was retrieved successfully, 0 otherwise (*SIGINFO is
 327    uninitialized in such case).  */
 328 int linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo);
 329
 330 #endif /* LINUX_NAT_H */