1
2/*--------------------------------------------------------------------*/
3/*--- Handle remote gdb protocol.             pub_core_gdbserver.h ---*/
4/*--------------------------------------------------------------------*/
5
6/*
7   This file is part of Valgrind, a dynamic binary instrumentation
8   framework.
9
10   Copyright (C) 2011-2017 Philippe Waroquiers
11
12   This program is free software; you can redistribute it and/or
13   modify it under the terms of the GNU General Public License as
14   published by the Free Software Foundation; either version 2 of the
15   License, or (at your option) any later version.
16
17   This program is distributed in the hope that it will be useful, but
18   WITHOUT ANY WARRANTY; without even the implied warranty of
19   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20   General Public License for more details.
21
22   You should have received a copy of the GNU General Public License
23   along with this program; if not, write to the Free Software
24   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
25   02111-1307, USA.
26
27   The GNU General Public License is contained in the file COPYING.
28*/
29
30#ifndef __PUB_CORE_GDBSERVER_H
31#define __PUB_CORE_GDBSERVER_H
32
33#include "pub_tool_gdbserver.h"
34#include "pub_core_options.h"
35#include "pub_core_threadstate.h"   // VgSchedReturnCode
36
37/* Return the default path prefix for the named pipes (FIFOs) used by vgdb/gdb
38   to communicate with valgrind */
39HChar* VG_(vgdb_prefix_default)(void);
40
41// After a fork or after an exec, call the below to (possibly) terminate
42// the previous gdbserver and then activate a new gdbserver
43// before any guest code execution, to e.g. allow the user to set
44// breakpoints before execution.
45// If VG_(clo_vgdb) == No, the below has no effect.
46void VG_(gdbserver_prerun_action) (ThreadId tid);
47
48// True if the initialisation of gdbserver was done,
49// i.e. VG_(gdbserver_prerun_action) was called.
50Bool VG_(gdbserver_init_done) (void);
51
52// True if gdbserver should stop execution for the specified stop at reason
53Bool VG_(gdbserver_stop_at) (VgdbStopAt stopat);
54
55// True if there is some activity from vgdb
56// If it returns True, then extern void VG_(gdbserver) can be called
57// to handle this incoming vgdb request.
58extern Bool VG_(gdbserver_activity) (ThreadId tid);
59
60// If connected to GDB, VG_(gdbserver_exit) reports to GDB that the process
61// is about to exit.
62// gdbserver is then stopped (using VG_(gdbserver) (0))
63void VG_(gdbserver_exit) (ThreadId tid, VgSchedReturnCode tids_schedretcode);
64
65/* On systems that defines PR_SET_PTRACER, verify if ptrace_scope is
66   is permissive enough for vgdb.
67   Otherwise, call set_ptracer.
68   This is especially aimed at Ubuntu >= 10.10 which has added
69   the ptrace_scope context. */
70void VG_(set_ptracer)(void);
71
72/* Called by low level to insert or remove a break or watch point.
73   Break or watch point implementation is done using help from the tool.
74   break point support implies some (small) specific instrumentation
75   taken in charge for all tools by m_translate.c.
76
77   Write/read/access watchpoint can only be provided by tools which are
78   tracking addressability and/or accessibility of memory
79   (so typically memcheck can provide it). Note that memcheck addressability
80   bits do not differentiate between read and write accessibility.
81   However, when accessing unaddressable byte, memcheck can differentiate
82   reads from write, thereby providing read/write or access watchpoints.
83
84   Note that gdbserver assumes that software breakpoint is supported
85   (as this will be done by re-instrumenting the code).
86   Note that len is ignored for software breakpoints. hardware_breakpoint
87   are not supported.
88
89   Returns True if the point has properly been inserted or removed
90   Returns False otherwise. */
91Bool VG_(gdbserver_point) (PointKind kind, Bool insert,
92                           Addr addr, int len);
93
94/* True if there is a breakpoint at addr. */
95Bool VG_(has_gdbserver_breakpoint) (Addr addr);
96
97/* Entry point invoked by vgdb when it uses ptrace to cause a gdbserver
98   invocation. A magic value is passed by vgdb in check as a verification
99   that the call has been properly pushed by vgdb. */
100extern void VG_(invoke_gdbserver) ( int check );
101
102// To be called by core (m_signals.c) before delivering a signal.
103// Returns False if gdb user asks to not pass the signal to the client.
104// Returns True if signal must be passed to the client, either because
105// no gdb is connected, or gdb instructs to pass the signal.
106// Note that if the below returns True, the signal might
107// still be ignored if this is the action desired by the
108// guest program. Using GDB, the user can also modify the signal to be
109// reported (e.g. changing the signo to pass to the guest).
110// If this function returns True, m_signals.c should deliver the signal
111// info as modified by VG_(gdbserver_report_signal).
112// If this function returns False, no signal should be reported.
113extern Bool VG_(gdbserver_report_signal) (vki_siginfo_t *info, ThreadId tid);
114
115// If no gdb is connected yet, wait for a gdb to connect and report
116// this (supposedly) fatal signal.
117// If a gdb is already connected, this does nothing (as normally
118// the signal was already reported to the already connected gdb).
119extern void VG_(gdbserver_report_fatal_signal) (const vki_siginfo_t *info,
120                                                ThreadId tid);
121
122// To be called by core before and after a client syscall.
123// If GDB has asked to observe the syscall, control will be given to GDB.
124// When Before is True, it is a report before the syscall,
125// False means a report after the syscall.
126extern void VG_(gdbserver_report_syscall) (Bool before, UWord sysno,
127                                           ThreadId tid);
128
129/* Entry point invoked by scheduler.c to execute the request
130   VALGRIND_CLIENT_MONITOR_COMMAND.
131   Returns True if command was not recognised. */
132extern Bool VG_(client_monitor_command) (HChar* cmd);
133
134/* software_breakpoint, single step and jump support ------------------------*/
135/* VG_(instrument_for_gdbserver_if_needed) allows to do "standard and easy"
136   instrumentation for gdbserver.
137   VG_(instrument_for_gdbserver_if_needed) does the following:
138      * checks if gdbserver instrumentation is needed for vge.
139      * if no gdbserver instrumentation needed,
140           returns sb_in
141      * otherwise
142        It will instrument sb_in to allow gdbserver to properly
143        handle breakpoints and single_stepping in sb_in.
144        All the target jumps of sb_in will also be invalidated
145        if these are not yet instrumented for gdbserver.
146        This allows to have single_step working, using a lazily
147        translation of the blocks which are being single stepped
148        in.
149
150   The typical usage of this function is to call it on the block
151   instrumented by the tool instrument function i.e. :
152     return VG_(instrument_for_gdbserver_if_needed) (sb_out,
153                                                     layout,
154                                                     vge,
155                                                     gWordTy,
156                                                     hWordTy);
157   where sb_out is the block instrumented by the tool.
158
159   If the block contains a call to a dirty helper that indirectly
160   calls gdbserver, then this dirty helper can (indirectly) change
161   the IP. This implies to jump to this IP after the call to
162   gdbserver. */
163extern IRSB* VG_(instrument_for_gdbserver_if_needed)
164     (IRSB* sb_in,                   /* block to be instrumented */
165      const VexGuestLayout* layout,
166      const VexGuestExtents* vge,
167      IRType gWordTy, IRType hWordTy);
168
169/* reason for which gdbserver connection must be finished */
170typedef
171   enum {
172      orderly_finish,
173      reset_after_error,
174      reset_after_fork} FinishReason;
175
176/* output various gdbserver statistics and status. */
177extern void VG_(gdbserver_status_output)(void);
178
179/* Shared structure between vgdb and the process running
180   under valgrind.
181   We define two variants: a 32 bit and a 64 bit.
182   The valgrind process will use the appropriate size,
183   according to the architecture.
184   vgdb will use what the valgrind process is using. */
185/* The below takes care that sizes will be 32 or 64 bits,
186   whatever the architecture. A.o., vgdb.c cannot use directly
187   the types from pub_core_threadstate.h as we want vgdb.c to
188   be independent of the arch it is debugging in case of bi-arch
189   Valgrind (e.g. x86 and amd64). So, the valgrind process must
190   give all the needed info/offset to vgdb in the below structure. */
191
192typedef
193   struct {
194      // nr of bytes vgdb has written to valgrind
195      volatile int written_by_vgdb;
196      // nr of bytes seen by valgrind
197      volatile int seen_by_valgrind;
198
199      // address at which gdbserver can be invoked
200      Addr32 invoke_gdbserver;
201
202      // address of VG_(threads) and various sizes
203      // and offset needed by vgdb.
204      Addr32 threads;
205      int vg_n_threads;
206      int sizeof_ThreadState;
207      int offset_status;
208      int offset_lwpid;
209
210      // PID of the vgdb that last connected to the Valgrind gdbserver.
211      // It will be set by vgdb after connecting.
212      int vgdb_pid;
213   } VgdbShared32;
214
215/* Same as VgdbShared32 but for 64 bits arch. */
216typedef
217   struct {
218      volatile int written_by_vgdb;
219      volatile int seen_by_valgrind;
220
221      Addr64 invoke_gdbserver;
222
223      Addr64 threads;
224      int vg_n_threads;
225      int sizeof_ThreadState;
226      int offset_status;
227      int offset_lwpid;
228
229      int vgdb_pid;
230   } VgdbShared64;
231
232// The below typedef makes the life of valgrind easier.
233// vgdb must however work explicitly with the specific 32 or 64 bits version.
234
235#if VEX_HOST_WORDSIZE == 8
236typedef VgdbShared64 VgdbShared;
237#elif VEX_HOST_WORDSIZE == 4
238typedef VgdbShared32 VgdbShared;
239#else
240# error "unexpected wordsize"
241#endif
242
243
244#endif   // __PUB_CORE_GDBSERVER_H
245/*--------------------------------------------------------------------*/
246/*--- end                                                          ---*/
247/*--------------------------------------------------------------------*/
248