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