VGDB(1)

VGDB(1)                              vgdb                              VGDB(1)

NAME
       vgdb - intermediary between Valgrind and GDB or a shell

SYNOPSIS
       vgdb [options]

DESCRIPTION
       vgdb ("Valgrind to GDB") is used as an intermediary between Valgrind
       and GDB or a shell. It has two usage modes:

        1. As a standalone utility, it is used from a shell command line to
           send monitor commands to a process running under Valgrind. For this
           usage, the vgdb OPTION(s) must be followed by the monitor command
           to send. To send more than one command, separate them with the -c
           option.

        2. In combination with GDB "target remote |" command, it is used as
           the relay application between GDB and the Valgrind gdbserver. For
           this usage, only OPTION(s) can be given, but no COMMAND can be
           given.

OPTIONS
       --pid=<number>
           Specifies the PID of the process to which vgdb must connect to.
           This option is useful in case more than one Valgrind gdbserver can
           be connected to. If the --pid argument is not given and multiple
           Valgrind gdbserver processes are running, vgdb will report the list
           of such processes and then exit.

       --vgdb-prefix
           Must be given to both Valgrind and vgdb if you want to change the
           default prefix for the FIFOs (named pipes) used for communication
           between the Valgrind gdbserver and vgdb.

       --wait=<number>
           Instructs vgdb to search for available Valgrind gdbservers for the
           specified number of seconds. This makes it possible start a vgdb
           process before starting the Valgrind gdbserver with which you
           intend the vgdb to communicate. This option is useful when used in
           conjunction with a --vgdb-prefix that is unique to the process you
           want to wait for. Also, if you use the --wait argument in the GDB
           "target remote" command, you must set the GDB remotetimeout to a
           value bigger than the --wait argument value. See option
           --max-invoke-ms (just below) for an example of setting the
           remotetimeout value.

       --max-invoke-ms=<number>
           Gives the number of milliseconds after which vgdb will force the
           invocation of gdbserver embedded in Valgrind. The default value is
           100 milliseconds. A value of 0 disables forced invocation. The
           forced invocation is used when vgdb is connected to a Valgrind
           gdbserver, and the Valgrind process has all its threads blocked in
           a system call.

           If you specify a large value, you might need to increase the GDB
           "remotetimeout" value from its default value of 2 seconds. You
           should ensure that the timeout (in seconds) is bigger than the
           --max-invoke-ms value. For example, for --max-invoke-ms=5000, the
           following GDB command is suitable:

                   (gdb) set remotetimeout 6

       --cmd-time-out=<number>
           Instructs a standalone vgdb to exit if the Valgrind gdbserver it is
           connected to does not process a command in the specified number of
           seconds. The default value is to never time out.

       --port=<portnr>
           Instructs vgdb to use tcp/ip and listen for GDB on the specified
           port nr rather than to use a pipe to communicate with GDB. Using
           tcp/ip allows one to have GDB running on one computer and debugging
           a Valgrind process running on another target computer. Example:

               # On the target computer, start your program under valgrind using
               valgrind --vgdb-error=0 prog
               # and then in another shell, run:
               vgdb --port=1234

           On the computer which hosts GDB, execute the command:

               gdb prog
               (gdb) target remote targetip:1234

           where targetip is the ip address or hostname of the target
           computer.

       -c
           To give more than one command to a standalone vgdb, separate the
           commands by an option -c. Example:

               vgdb v.set log_output -c leak_check any

       -l
           Instructs a standalone vgdb to report the list of the Valgrind
           gdbserver processes running and then exit.

       -T
           Instructs vgdb to add timestamps to vgdb information messages.

       -D
           Instructs a standalone vgdb to show the state of the shared memory
           used by the Valgrind gdbserver. vgdb will exit after having shown
           the Valgrind gdbserver shared memory state.

       -d
           Instructs vgdb to produce debugging output. Give multiple -d args
           to increase the verbosity. When giving -d to a relay vgdb, you
           better redirect the standard error (stderr) of vgdb to a file to
           avoid interaction between GDB and vgdb debugging output.

SEE ALSO
       valgrind(1), $INSTALL/share/doc/valgrind/html/index.html or
       http://www.valgrind.org/docs/manual/index.html,

       Debugging your program using Valgrind's gdbserver and GDB[1] vgdb[2],
       Valgrind monitor commands[3].

AUTHOR
       Philippe Waroquiers.

NOTES
        1. Debugging your program using Valgrind's gdbserver and GDB
           http://www.valgrind.org/docs/manual/manual-core-adv.html#manual-core-adv.gdbserver

        2. vgdb
           http://www.valgrind.org/docs/manual/manual-core-adv.html#manual-core-adv.vgdb

        3. Valgrind monitor commands
           http://www.valgrind.org/docs/manual/manual-core-adv.html#manual-core-adv.valgrind-monitor-commands

Release 3.16.1                    06/28/2020                           VGDB(1)