coregrind/pub_core_gdbserver.h

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/*--- Handle remote gdb protocol.             pub_core_gdbserver.h ---*/
/*--------------------------------------------------------------------*/

/*
   This file is part of Valgrind, a dynamic binary instrumentation
   framework.

   Copyright (C) 2011-2017 Philippe Waroquiers

   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 2 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, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file COPYING.
*/

#ifndef __PUB_CORE_GDBSERVER_H
#define __PUB_CORE_GDBSERVER_H

#include "pub_tool_gdbserver.h"
#include "pub_core_options.h"
#include "pub_core_threadstate.h"   // VgSchedReturnCode

/* Return the default path prefix for the named pipes (FIFOs) used by vgdb/gdb
   to communicate with valgrind */
HChar* VG_(vgdb_prefix_default)(void);

// After a fork or after an exec, call the below to (possibly) terminate
// the previous gdbserver and then activate a new gdbserver
// before any guest code execution, to e.g. allow the user to set
// breakpoints before execution.
// If VG_(clo_vgdb) == No, the below has no effect.
void VG_(gdbserver_prerun_action) (ThreadId tid);

// True if the initialisation of gdbserver was done,
// i.e. VG_(gdbserver_prerun_action) was called.
Bool VG_(gdbserver_init_done) (void);

// True if gdbserver should stop execution for the specified stop at reason
Bool VG_(gdbserver_stop_at) (VgdbStopAt stopat);

// True if there is some activity from vgdb
// If it returns True, then extern void VG_(gdbserver) can be called
// to handle this incoming vgdb request.                                
extern Bool VG_(gdbserver_activity) (ThreadId tid);

// If connected to GDB, VG_(gdbserver_exit) reports to GDB that the process
// is about to exit.
// gdbserver is then stopped (using VG_(gdbserver) (0))
void VG_(gdbserver_exit) (ThreadId tid, VgSchedReturnCode tids_schedretcode);

/* On systems that defines PR_SET_PTRACER, verify if ptrace_scope is
   is permissive enough for vgdb.
   Otherwise, call set_ptracer.
   This is especially aimed at Ubuntu >= 10.10 which has added
   the ptrace_scope context. */
void VG_(set_ptracer)(void);

/* Called by low level to insert or remove a break or watch point.
   Break or watch point implementation is done using help from the tool.
   break point support implies some (small) specific instrumentation
   taken in charge for all tools by m_translate.c.
   
   Write/read/access watchpoint can only be provided by tools which are
   tracking addressability and/or accessibility of memory 
   (so typically memcheck can provide it). Note that memcheck addressability
   bits do not differentiate between read and write accessibility.
   However, when accessing unaddressable byte, memcheck can differentiate
   reads from write, thereby providing read/write or access watchpoints.

   Note that gdbserver assumes that software breakpoint is supported
   (as this will be done by re-instrumenting the code).
   Note that len is ignored for software breakpoints. hardware_breakpoint
   are not supported.

   Returns True if the point has properly been inserted or removed
   Returns False otherwise. */
Bool VG_(gdbserver_point) (PointKind kind, Bool insert, 
                           Addr addr, int len);

/* True if there is a breakpoint at addr. */
Bool VG_(has_gdbserver_breakpoint) (Addr addr);

/* Entry point invoked by vgdb when it uses ptrace to cause a gdbserver
   invocation. A magic value is passed by vgdb in check as a verification
   that the call has been properly pushed by vgdb. */
extern void VG_(invoke_gdbserver) ( int check );

// To be called by core (m_signals.c) before delivering a signal.
// Returns False if gdb user asks to not pass the signal to the client.
// Returns True if signal must be passed to the client, either because
// no gdb is connected, or gdb instructs to pass the signal.
// Note that if the below returns True, the signal might
// still be ignored if this is the action desired by the
// guest program. Using GDB, the user can also modify the signal to be
// reported (e.g. changing the signo to pass to the guest).
// If this function returns True, m_signals.c should deliver the signal
// info as modified by VG_(gdbserver_report_signal).
// If this function returns False, no signal should be reported.
extern Bool VG_(gdbserver_report_signal) (vki_siginfo_t *info, ThreadId tid);

// If no gdb is connected yet, wait for a gdb to connect and report
// this (supposedly) fatal signal.
// If a gdb is already connected, this does nothing (as normally 
// the signal was already reported to the already connected gdb).
extern void VG_(gdbserver_report_fatal_signal) (const vki_siginfo_t *info,
                                                ThreadId tid);

// To be called by core before and after a client syscall.
// If GDB has asked to observe the syscall, control will be given to GDB.
// When Before is True, it is a report before the syscall,
// False means a report after the syscall.
extern void VG_(gdbserver_report_syscall) (Bool before, UWord sysno,
                                           ThreadId tid);

/* Entry point invoked by scheduler.c to execute the request 
   VALGRIND_CLIENT_MONITOR_COMMAND.
   Returns True if command was not recognised. */
extern Bool VG_(client_monitor_command) (HChar* cmd);

/* software_breakpoint, single step and jump support ------------------------*/
/* VG_(instrument_for_gdbserver_if_needed) allows to do "standard and easy"
   instrumentation for gdbserver.
   VG_(instrument_for_gdbserver_if_needed) does the following:
      * checks if gdbserver instrumentation is needed for vge.
      * if no gdbserver instrumentation needed,
           returns sb_in
      * otherwise 
        It will instrument sb_in to allow gdbserver to properly
        handle breakpoints and single_stepping in sb_in.
        All the target jumps of sb_in will also be invalidated
        if these are not yet instrumented for gdbserver.
        This allows to have single_step working, using a lazily
        translation of the blocks which are being single stepped
        in. 

   The typical usage of this function is to call it on the block
   instrumented by the tool instrument function i.e. :
     return VG_(instrument_for_gdbserver_if_needed) (sb_out, 
                                                     layout, 
                                                     vge, 
                                                     gWordTy, 
                                                     hWordTy);
   where sb_out is the block instrumented by the tool.

   If the block contains a call to a dirty helper that indirectly
   calls gdbserver, then this dirty helper can (indirectly) change
   the IP. This implies to jump to this IP after the call to
   gdbserver. */
extern IRSB* VG_(instrument_for_gdbserver_if_needed)
     (IRSB* sb_in,                   /* block to be instrumented */
      const VexGuestLayout* layout,
      const VexGuestExtents* vge,
      IRType gWordTy, IRType hWordTy);

/* reason for which gdbserver connection must be finished */
typedef
   enum {
      orderly_finish,
      reset_after_error,
      reset_after_fork} FinishReason;

/* output various gdbserver statistics and status. */
extern void VG_(gdbserver_status_output)(void);

/* Shared structure between vgdb and the process running 
   under valgrind.
   We define two variants: a 32 bit and a 64 bit.
   The valgrind process will use the appropriate size,
   according to the architecture.
   vgdb will use what the valgrind process is using. */
/* The below takes care that sizes will be 32 or 64 bits,
   whatever the architecture. A.o., vgdb.c cannot use directly
   the types from pub_core_threadstate.h as we want vgdb.c to
   be independent of the arch it is debugging in case of bi-arch
   Valgrind (e.g. x86 and amd64). So, the valgrind process must
   give all the needed info/offset to vgdb in the below structure. */

typedef 
   struct {
      // nr of bytes vgdb has written to valgrind
      volatile int written_by_vgdb;
      // nr of bytes seen by valgrind
      volatile int seen_by_valgrind;
      
      // address at which gdbserver can be invoked
      Addr32 invoke_gdbserver;

      // address of VG_(threads) and various sizes
      // and offset needed by vgdb.
      Addr32 threads;
      int vg_n_threads;
      int sizeof_ThreadState;
      int offset_status;
      int offset_lwpid;

      // PID of the vgdb that last connected to the Valgrind gdbserver.
      // It will be set by vgdb after connecting.
      int vgdb_pid;
   } VgdbShared32;

/* Same as VgdbShared32 but for 64 bits arch. */
typedef 
   struct {
      volatile int written_by_vgdb;
      volatile int seen_by_valgrind;
      
      Addr64 invoke_gdbserver;

      Addr64 threads;
      int vg_n_threads;
      int sizeof_ThreadState;
      int offset_status;
      int offset_lwpid;

      int vgdb_pid;
   } VgdbShared64;

// The below typedef makes the life of valgrind easier.
// vgdb must however work explicitly with the specific 32 or 64 bits version.

#if VEX_HOST_WORDSIZE == 8
typedef VgdbShared64 VgdbShared;
#elif VEX_HOST_WORDSIZE == 4
typedef VgdbShared32 VgdbShared;
#else
# error "unexpected wordsize"
#endif


#endif   // __PUB_CORE_GDBSERVER_H
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