include/pub_tool_gdbserver.h

   1
   2 /*--------------------------------------------------------------------*/
   3 /*--- Handle remote gdb protocol.             pub_tool_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, see <http://www.gnu.org/licenses/>.
  24
  25    The GNU General Public License is contained in the file COPYING.
  26 */
  27
  28 #ifndef __PUB_TOOL_GDBSERVER_H
  29 #define __PUB_TOOL_GDBSERVER_H
  30
  31 #include "pub_tool_basics.h"   // VG_ macro
  32
  33 //--------------------------------------------------------------------
  34 // PURPOSE: This module provides the support to have a gdb
  35 // connecting to a valgrind process using remote gdb protocol. It provides
  36 //  * A function to allow a tool (or the valgrind core) to
  37 //    wait for a gdb to connect and then handle gdb commands.
  38 //    Typically, this can be used to let the user debug the process
  39 //    when valgrind reports an error.
  40 //  * A function allowing to instrument the code to support gdb breakpoints.
  41 //  * A function allowing the tool to support watchpoints.
  42 //  * A utility function to help implementing the processing of the
  43 //    gdb_monitor_command strings.
  44
  45
  46 // Function to be used by tool or coregrind to allow a gdb to connect
  47 // to this process.
  48 // Calling VG_(gdbserver) with tid > 0 means to let a debugger attach
  49 // to the valgrind process. gdbserver will report to gdb that the
  50 // process stopped in thread tid.
  51 // Calling VG_(gdbserver) with tid == 0 indicates to close
  52 // the connection with GDB (if still open) and stop gdbserver.
  53 //--------------------------------------------------------------------
  54 extern void VG_(gdbserver) ( ThreadId tid );
  55
  56 /* defines the various kinds of breakpoints that gdbserver
  57    might ask to insert/remove. Note that the below matches
  58    the gdbserver protocol definition. The level of support
  59    of the various breakpoint kinds depends on the tool.
  60
  61    For the moment, it is unclear how a tool would implement
  62    hardware_breakpoint in valgrind  :).
  63
  64    software_breakpoint implies some (small) specific
  65    instrumentation to be done for gdbserver. This instrumentation
  66    is implemented for all tools in m_translate.c.
  67
  68    write/read/access watchpoints can only be done by tools
  69    which are maintaining some notion of address accessibility
  70    as part of their instrumentation. watchpoints can then
  71    be done by marking the watched address(es) as not accessible.
  72    But instead of giving back an error (or whatever the tool
  73    wants to do with unaccessible mechanism), the tool must then
  74    just call gdbserver. See memcheck for an example of reusing
  75    accessibility for watchpoint support.
  76 */
  77 typedef
  78    enum {
  79       software_breakpoint,
  80       hardware_breakpoint,
  81       write_watchpoint,
  82       read_watchpoint,
  83       access_watchpoint } PointKind;
  84 extern const HChar* VG_(ppPointKind) (PointKind kind);
  85
  86
  87 /* watchpoint support --------------------------------------*/
  88 /* True if one or more bytes in [addr, addr+len[ are being watched by
  89    gdbserver for write or read or access.
  90    In addition, VG_(is_watched) will invoke gdbserver if
  91    the access provided by the tool matches the watchpoint kind.
  92    For this, the tool must pass the kind of access it has detected:
  93       write_watchpoint indicates the tool has detected a write
  94       read_watchpoint indicates the tool has detected a read
  95       access_watchpoint indicates the tool has detected an access but does
  96       not know if this is a read or a write
  97 */
  98 extern Bool VG_(is_watched)(PointKind kind, Addr addr, Int szB);
  99
 100 extern void VG_(needs_watchpoint) (
 101    // indicates the given Addr/len is being watched (insert)
 102    // or not watched anymore (! insert).
 103    // gdbserver will maintain the list of watched addresses.
 104    // The tool can use VG_(is_watched) to verify if an
 105    // access to an Addr is in one of the watched intervals.
 106    // Must return True if the watchpoint has been properly inserted or
 107    // removed. False if not supported.
 108    // Note that an address can only be watched for a single kind.
 109    // The tool must be ready to be called successively with
 110    // multiple kinds for the same addr and len and with
 111    // different kinds. The last kind must replace the previous values.
 112    // Behaviour with multiple watches having overlapping addr+len
 113    // is undefined.
 114    Bool (*watchpoint) (PointKind kind, Bool insert, Addr addr, SizeT len)
 115 );
 116
 117
 118 // can be used during the processing of the VG_USERREQ__GDB_MONITOR_COMMAND
 119 // tool client request to output information to gdb or vgdb.
 120 // The output of VG_(gdb_printf) is not subject to 'output control'
 121 // by the user: e.g. the monitor command 'v.set log_output' has no effect.
 122 // The output of VG_(gdb_printf) is given to gdb/vgdb. The only case
 123 // in which this output is not given to gdb/vgdb is when the connection
 124 // with gdb/vgdb has been lost : in such a case, output is written
 125 // to the valgrind log output.
 126 // To produce some output which is subject to user output control via
 127 // monitor command v.set gdb_output or mixed output, use VG_(printf)
 128 // or VG_(umsg) or similar.
 129 // Typically, VG_(gdb_printf) has to be used when there is no point
 130 // having this output in the output log of Valgrind. Examples
 131 // is the monitor help output, or if vgdb is used to implement
 132 // 'tool control scripts' such as callgrind_control.
 133 extern UInt VG_(gdb_printf) ( const HChar *format, ... ) PRINTF_CHECK(1, 2);
 134
 135 /* Utility functions to (e.g.) parse gdb monitor commands.
 136
 137    keywords is a set of keywords separated by a space
 138    keyword_id will search for the keyword starting with the string input_word
 139    and return its position.
 140    It returns -1 if no keyword matches.
 141    It returns -2 if two or more keywords are starting with input_word
 142                  and none of these matches exactly input_word
 143    Example with keywords = "hello world here is hell" :
 144    input_word    result
 145    ----------    ------
 146    paradise   => -1
 147    i          =>  3
 148    hell       =>  4
 149    hel        => -2
 150    ishtar     => -1
 151
 152    report indicates when to output an error msg with VG_(gdb_printf).
 153    kwd_report_none : no error is reported.
 154    kwd_report_all : the error msg will show all possible keywords
 155    kwd_report_duplicated_matches : the error msg will show only the
 156      ambiguous matches.
 157 */
 158 typedef
 159    enum {
 160       kwd_report_none,
 161       kwd_report_all,
 162       kwd_report_duplicated_matches } kwd_report_error;
 163 extern Int VG_(keyword_id) (const HChar* keywords, const HChar* input_word,
 164                             kwd_report_error report);
 165
 166 /* Extract an address and (optionally) a size from the string
 167    currently being parsed by strtok_r (see pub_tool_libcbase.h).
 168    If no size in the string, keeps the current value of szB.
 169    If parsing is ok,
 170      returns True.
 171    If parsing is not ok;
 172      set *address and *szB to 0,
 173      reports problem to the user using VG_(gdb_printf)
 174      returns False. */
 175 extern Bool VG_(strtok_get_address_and_size) (Addr* address,
 176                                               SizeT* szB,
 177                                               HChar **ssaveptr);
 178
 179 /* Print various statistics about Valgrind core,
 180    and optionally tool and memory statistics. */
 181 extern void VG_(print_all_stats) (Bool memory_stats, Bool tool_stats);
 182
 183 #endif   // __PUB_TOOL_GDBSERVER_H
 184
 185 /*--------------------------------------------------------------------*/
 186 /*--- end                                                          ---*/
 187 /*--------------------------------------------------------------------*/