`dumper`

Dump the postmortem state of a program (QNX)

Syntax:

dumper [-d path] [-m] [-n] [-p pid] [-v] &

Options:

-d path

The name of the directory in which postmortem dump files are written. The default is the user's home directory.

-m

Don't dump memory.

-n

Save sequential dumps. Each dump is saved in a file whose name is of the form:

executable.num.core

where num starts at 1 and increases until the filename doesn't already exist.

-p pid

Save a dump file for this process immediately, and then exit dumper.

-v

Verbose output.

Description:

On a Momentics system, dumper starts with dumper -d /var/dumps.

The dumper utility runs in the background and provides a postmortem dump service for all processes. Whenever a program terminates abnormally, a dump of the current state of the program is written to disk. The dump filename is the same as the program name with a .core extension. For example, if the program name is experiment, the dump is written to. experiment.core in the user's home directory.

You can use the -d option to force all dumps into a single directory rather than into /var/dumps.

Dump files can be large, so make sure the destination filesystem has lots of space.

The -p option lets you get a dump immediately for a particular process. If -p is specified, dumper doesn't run in the background, but exits right away.

You can use a debugger such as gdb to examine a dump file:

gdb program_binary program_core

For example:

gdb /usr/photon/bin/pterm /var/dumps/pterm.core

A program may terminate in one of two ways. It may exit cleanly under its own control, returning an exit status, or it may be forcibly terminated by the receipt of a signal it isn't prepared to handle. In the latter case, dumper writes a dump file for the following set of signals:

Signal	Description
SIGABRT	Program-called abort function
SIGBUS	Parity error
SIGEMT	EMT instruction
SIGFPE	Floating-point error or division by zero
SIGILL	Illegal instruction executed
SIGQUIT	Quit
SIGSEGV	Segmentation violation
SIGSYS	Bad argument to a system call
SIGTRAP	Trace trap (not reset when caught)
SIGXCPU	Exceeded the CPU limit
SIGXFSZ	Exceeded the file size limit

You can force the dump of a running program by setting one of the preceding signals, assuming that the program isn't masking or handling the signal itself. For example, to force a dump using the kill command and a process ID (pid):

kill -SIGABRT pid

To force a dump using the slay utility and the process name:

slay -s SIGABRT process_name

Examples:

Start dumper, with dump files to be written to the default directory:

dumper &

Start dumper, with dump files to be placed in the directory /home/dumps:

dumper -d /home/dumps &

Exit status:

The dumper utility normally doesn't terminate. However, it may terminate if it encounters an error on startup (for instance, if it wasn't run by root) or if it receives a signal.

0: A signal was received and dumper shut down successfully.
1: An error was encountered on startup (not run by root or bad command-line options).

dumper