binutils-gdb/gdb/target/waitstatus.h

/* Target waitstatus definitions and prototypes.

   Copyright (C) 1990-2021 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#ifndef TARGET_WAITSTATUS_H
#define TARGET_WAITSTATUS_H

#include "gdbsupport/gdb_signals.h"

/* Stuff for target_wait.  */

/* Generally, what has the program done?  */
enum target_waitkind
{
  /* The program has exited.  The exit status is in value.integer.  */
  TARGET_WAITKIND_EXITED,

  /* The program has stopped with a signal.  Which signal is in
     value.sig.  */
  TARGET_WAITKIND_STOPPED,

  /* The program has terminated with a signal.  Which signal is in
     value.sig.  */
  TARGET_WAITKIND_SIGNALLED,

  /* The program is letting us know that it dynamically loaded
     something (e.g. it called load(2) on AIX).  */
  TARGET_WAITKIND_LOADED,

  /* The program has forked.  A "related" process' PTID is in
     value.related_pid.  I.e., if the child forks, value.related_pid
     is the parent's ID.  */
  TARGET_WAITKIND_FORKED,
 
  /* The program has vforked.  A "related" process's PTID is in
     value.related_pid.  */
  TARGET_WAITKIND_VFORKED,
 
  /* The program has exec'ed a new executable file.  The new file's
     pathname is pointed to by value.execd_pathname.  */
  TARGET_WAITKIND_EXECD,
  
  /* The program had previously vforked, and now the child is done
     with the shared memory region, because it exec'ed or exited.
     Note that the event is reported to the vfork parent.  This is
     only used if GDB did not stay attached to the vfork child,
     otherwise, a TARGET_WAITKIND_EXECD or
     TARGET_WAITKIND_EXIT|SIGNALLED event associated with the child
     has the same effect.  */
  TARGET_WAITKIND_VFORK_DONE,

  /* The program has entered or returned from a system call.  On
     HP-UX, this is used in the hardware watchpoint implementation.
     The syscall's unique integer ID number is in
     value.syscall_id.  */
  TARGET_WAITKIND_SYSCALL_ENTRY,
  TARGET_WAITKIND_SYSCALL_RETURN,

  /* Nothing happened, but we stopped anyway.  This perhaps should
     be handled within target_wait, but I'm not sure target_wait
     should be resuming the inferior.  */
  TARGET_WAITKIND_SPURIOUS,

  /* An event has occured, but we should wait again.
     Remote_async_wait() returns this when there is an event
     on the inferior, but the rest of the world is not interested in
     it.  The inferior has not stopped, but has just sent some output
     to the console, for instance.  In this case, we want to go back
     to the event loop and wait there for another event from the
     inferior, rather than being stuck in the remote_async_wait()
     function.  This way the event loop is responsive to other events,
     like for instance the user typing.  */
  TARGET_WAITKIND_IGNORE,
 
  /* The target has run out of history information,
     and cannot run backward any further.  */
  TARGET_WAITKIND_NO_HISTORY,
 
  /* There are no resumed children left in the program.  */
  TARGET_WAITKIND_NO_RESUMED,

  /* The thread was created.  */
  TARGET_WAITKIND_THREAD_CREATED,

  /* The thread has exited.  The exit status is in value.integer.  */
  TARGET_WAITKIND_THREAD_EXITED,
};

struct target_waitstatus
{
  /* Default constructor.  */
  target_waitstatus () = default;

  /* Copy constructor.  */

  target_waitstatus (const target_waitstatus &other)
  {
    m_kind = other.m_kind;
    m_value = other.m_value;

    if (m_kind == TARGET_WAITKIND_EXECD)
      m_value.execd_pathname = xstrdup (m_value.execd_pathname);
  }

  /* Move constructor.  */

  target_waitstatus (target_waitstatus &&other)
  {
    m_kind = other.m_kind;
    m_value = other.m_value;

    if (m_kind == TARGET_WAITKIND_EXECD)
      other.m_value.execd_pathname = nullptr;

    other.reset ();
  }

  /* Copy assignment operator.  */

  target_waitstatus &operator= (const target_waitstatus &rhs)
  {
    this->reset ();
    m_kind = rhs.m_kind;
    m_value = rhs.m_value;

    if (m_kind == TARGET_WAITKIND_EXECD)
      m_value.execd_pathname = xstrdup (m_value.execd_pathname);

    return *this;
  }

  /* Move assignment operator.  */

  target_waitstatus &operator= (target_waitstatus &&rhs)
  {
    this->reset ();
    m_kind = rhs.m_kind;
    m_value = rhs.m_value;

    if (m_kind == TARGET_WAITKIND_EXECD)
      rhs.m_value.execd_pathname = nullptr;

    rhs.reset ();

    return *this;
  }

  /* Destructor.  */

  ~target_waitstatus ()
  {
    this->reset ();
  }

  /* Setters: set the wait status kind plus any associated data.  */

  void set_exited (int exit_status)
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_EXITED;
    m_value.exit_status = exit_status;
  }

  void set_stopped (gdb_signal sig)
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_STOPPED;
    m_value.sig = sig;
  }

  void set_signalled (gdb_signal sig)
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_SIGNALLED;
    m_value.sig = sig;
  }

  void set_loaded ()
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_LOADED;
  }

  void set_forked (ptid_t child_ptid)
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_FORKED;
    m_value.child_ptid = child_ptid;
  }

  void set_vforked (ptid_t child_ptid)
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_VFORKED;
    m_value.child_ptid = child_ptid;
  }

  void set_execd (gdb::unique_xmalloc_ptr<char> execd_pathname)
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_EXECD;
    m_value.execd_pathname = execd_pathname.release ();
  }

  void set_vfork_done ()
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_VFORK_DONE;
  }

  void set_syscall_entry (int syscall_number)
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_SYSCALL_ENTRY;
    m_value.syscall_number = syscall_number;
  }

  void set_syscall_return (int syscall_number)
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_SYSCALL_RETURN;
    m_value.syscall_number = syscall_number;
  }

  void set_spurious ()
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_SPURIOUS;
  }

  void set_ignore ()
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_IGNORE;
  }

  void set_no_history ()
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_NO_HISTORY;
  }

  void set_no_resumed ()
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_NO_RESUMED;
  }

  void set_thread_created ()
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_THREAD_CREATED;
  }

  void set_thread_exited (int exit_status)
  {
    this->reset ();
    m_kind = TARGET_WAITKIND_THREAD_EXITED;
    m_value.exit_status = exit_status;
  }

  /* Get the kind of this wait status.  */

  target_waitkind kind () const
  {
    return m_kind;
  }

  /* Getters for the associated data.

     Getters can only be used if the wait status is of the appropriate kind.
     See the setters above or the assertions below to know which data is
     associated to which kind.  */

  int exit_status () const
  {
    gdb_assert (m_kind == TARGET_WAITKIND_EXITED
		|| m_kind == TARGET_WAITKIND_THREAD_EXITED);
    return m_value.exit_status;
  }

  gdb_signal sig () const
  {
    gdb_assert (m_kind == TARGET_WAITKIND_STOPPED
		|| m_kind == TARGET_WAITKIND_SIGNALLED);
    return m_value.sig;
  }

  ptid_t child_ptid () const
  {
    gdb_assert (m_kind == TARGET_WAITKIND_FORKED
		|| m_kind == TARGET_WAITKIND_VFORKED);
    return m_value.child_ptid;
  }

  const char *execd_pathname () const
  {
    gdb_assert (m_kind == TARGET_WAITKIND_EXECD);
    return m_value.execd_pathname;
  }

  int syscall_number () const
  {
    gdb_assert (m_kind == TARGET_WAITKIND_SYSCALL_ENTRY
		|| m_kind == TARGET_WAITKIND_SYSCALL_RETURN);
    return m_value.syscall_number;
  }

private:
  /* Reset the wait status to its original state.  */
  void reset ()
  {
    if (m_kind == TARGET_WAITKIND_EXECD)
      xfree (m_value.execd_pathname);

    m_kind = TARGET_WAITKIND_IGNORE;
  }

  target_waitkind m_kind = TARGET_WAITKIND_IGNORE;

  /* Additional information about the event.  */
  union
    {
      /* Exit status */
      int exit_status;
      /* Signal number */
      enum gdb_signal sig;
      /* Forked child pid */
      ptid_t child_ptid;
      /* execd pathname */
      char *execd_pathname;
      /* Syscall number */
      int syscall_number;
    } m_value;
};

/* Extended reasons that can explain why a target/thread stopped for a
   trap signal.  */

enum target_stop_reason
{
  /* Either not stopped, or stopped for a reason that doesn't require
     special tracking.  */
  TARGET_STOPPED_BY_NO_REASON,

  /* Stopped by a software breakpoint.  */
  TARGET_STOPPED_BY_SW_BREAKPOINT,

  /* Stopped by a hardware breakpoint.  */
  TARGET_STOPPED_BY_HW_BREAKPOINT,

  /* Stopped by a watchpoint.  */
  TARGET_STOPPED_BY_WATCHPOINT,

  /* Stopped by a single step finishing.  */
  TARGET_STOPPED_BY_SINGLE_STEP
};

/* Prototypes */

/* Return a pretty printed form of target_waitstatus.  */
std::string target_waitstatus_to_string (const struct target_waitstatus *);

#endif /* TARGET_WAITSTATUS_H */