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PMDB(1) General Commands Manual PMDB(1)

pmdb — debugger

pmdb [-c core] [-p pid] program ...

The pmdb utility can be used to see what is happening inside a running process or to catch program crashes and examine the state at the time of the crash. The only way to start pmdb at this moment is to specify the name of the program to be debugged and all its arguments on the command line. Optionally, -c can be used to specify a core file to examine. It is also possible to debug a process that is already running by specifying the process's PID to the -p flag. This causes the process to be put in STOPPED state until execution is resumed either by an explicit command to pmdb or by exiting pmdb. The program is controlled from a command line which usually gives the prompt "pmdb>".

A loaded program can be in one of three possible states:

LOADED
This is the initial state. The program is not running, it can't be examined (because it doesn't have any state). The only thing that can be done to the process is to start it with the run command.
RUNNING
When a process is RUNNING, the only way to affect it is through signals sent to it. Unless a signal is ignored with the signal ignore command, it will be caught by pmdb and the process will go into the STOPPED state.
STOPPED
A stopped process can be examined, changed and restarted with the continue command.

examine symbol|address
Fetch and display in hex a word at address or symbol.
regs
Show the contents of the processor registers at the moment the process was STOPPED.
trace
Show the function call trace of the currently STOPPED process.
run
Start running a LOADED process.
continue
Continue a STOPPED process.
kill
Unconditionally kills the debugged process and puts it in the LOADED state.
signal ignore|stop signum|signame
Sets the signal state for the specified signal to either ignore it and pass it to the process or to stop the process.
sigstate
Shows which signals are currently ignored.
setenv var val
Sets the environment variable var to the value val.
break symname|addr
Sets a breakpoint at the symbol symname or the numerical address addr.
step
Resumes execution just like continue, but stops it again as soon as possible after executing at least one instruction.
sym_load fname offs
Loads a symbol table from the file fname at the offset offs.
help
Shows a short help.
quit
Kills the process (if necessary) and exits.
exit
Alias for quit.

core(5)

The pmdb debugger was written because the author believed that gdb(1) was too bloated and hairy to run on OpenBSD/sparc64.

The command syntax is really poor and ad hoc at this moment. Most of the command names and arguments will change as soon as the command line interface is replaced.

December 24, 2011 OpenBSD-5.1