README.md

gdb-ext-examples

This repository holds a small collection of sample gdb extensions.

Structure

Each sample extension is self-contained and in its own sub-directory.

For each extension, there is a sample C application which can be used to try it out. A MAKEFILE is provided to build the appliction. The README.md file gives a short introduction on how to use the extension. There is a *.gdb file which can be used to load the extension and configure GDB for it (if this is required). Usually, each application has a function called break_here in which a breakpoint can be set. The *.gdb file should do this already. Start GDB with the provided command line.

Introduction

One can write simple python extensions inline in GDB:

(gdb) python
class HelloWorld(gdb.Command):

  def __init__(self):
    super(HelloWorld, self).__init__("hello", gdb.COMMAND_STATUS)

  def invoke(self, arg, from_tty):
    print("Hello World")

HelloWorld()
end

This creates a new GDB command with the name hello and instantiates it. It can be used afterwards and will print "Hello World":

(gdb) hello
Hello World

(gdb) python gdb.set_convenience_variable("foo", 5)
(gdb) print $foo + 5
$1 = 10

GDB documentation

The online documentation is only available for the latest release:

• script extensions
• python extensions
• guile extensions

If an older GDB version is used, one can build the documentation from source:

• wget https://ftp.gnu.org/gnu/gdb/gdb-13.1.tar.xz
• tar -xJf gdb-13.1.tar.xz
• cd gdb-13.1/gdb/
• ./configure
• make -C doc html MAKEINFO=makeinfo MAKEINFOFLAGS='--no-split' -j4
• xdg-open doc/gdb.html

See the build_gdb_docs.sh script.

License

Unlicense / Public domain