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|
# gdb
--------------------------------------------------------------------------------
# toc
------
|gdb|
|opts|
|prompt|
|user_commands|
|hooks|
|flows|
# gdb(1) *gdb*
=========
gdb [opts] [exe [coredump | pid]]
gdb [opts] --args exe <exe-args>
opts: *opts*
-p <pid> attach to pid
-x <file> execute script <file> before prompt
-ex <cmd> execute command <cmd> before prompt
--tty <tty> set I/O tty for debugee (see *prompt* for details)
prompt: *prompt*
tty <tty> set <tty> as tty for debugee. make sure nobody
reads from target tty, easiest is to spawn a shell
and run
> while true; do sleep 1024; done
set follow-fork-mode <child | parent>
specify which process to follow on fork(2)
sharedlibrary [regex]
load symbols of shared lib, if REGEX then only symbols
for matching libs
break [-qualified] <sym> thread <tnum>
set a breakpoint only on a specific thread
-qualified: sym must be fully qualified (quiet handy
to set breakpoints on C symbols in C++ contexts)
rbreak <regex> set breakpoints based on symbols matching regex
<regex> is internally expanded to .*<regex>.*
so 'rbreak foo' matches barfoobar()
command [bp_list] define commands to run after breakpoint hit if
BP_LIST not supplied attach command to last
created bp
BP_LIST: space separates list, eg 'command 2 5-8'
to run command for bp 2,5,6,7,8
info functions [regex]
list functions according to REGEX, if REGEX empty,
list all
info variables [regex]
list variables according to REGEX, if REGEX empty,
list all
info handle [signal]
list bevahior for SIGNAL, if SIGNAL empty list all signals
handle signal <action>
configure how gdb handles SIGNAL which is ment for the debugee
<action>:
stop/nostop catch signal in gdb and break
print/noprint print message when gdb catches signal
pass/nopass pass signal down to debugee
noignore/ignore synonyms for
catch signal <signal>
create a catchpoint for SIGNAL
user commands: *user_commands*
define <cmd> defines user command <cmd> to be run
# cmds in prompt or script
end
document <cmd> define documentation for cmd <cmd>
# docu
end
help user-defined list user defined commands
help <cmd> list documentation for command <cmd>
hooks: *hooks*
define hook-<cmd> run commands defined in hook before
# cmds executing <cmd>
end
define hookpost-<cmd> run commands defined in hookpost after
# cmds executing <cmd>
end
flows: *flows*
# catch SIGSEGV and execute some actions once it happends
- script:
catch signal SIGSEGV
command
bt
c
end
# quickly execute gdb command on running process, eg get backtrace from
# thread 1
- cmd:
$> gdb -ex 'thread 1' -ex 'bt' -p <PID>
# script gdb for automating debugging sessions
- script: run.gdb
set pagination off
break mmap
command
info reg rdi rsi rdx
bt
c
end
#initial drop
c
- cmd:
$> gdb -p <PID> -x ./run.gdb --batch &> run.log
# workaround command + finish bug
# issue: when using finish in a command block, actions after finish will not
# be executed
- script:
define handler
bt
finish
info reg rax
end
command
handler
end
--------------------------------------------------------------------------------
vim:ft=help:sts=2:et:tw=80:cc=80:fo+=t
|
