dumper

Dump the postmortem state of a program (QNX)

Syntax:

dumper [-d path] [-m] [-n] [-P] [-p pid] [-s size[G|M|K]]
       [-t] [-v] [-w] [-z level] &

Runs on:

Neutrino

Options:

-d path
The name of the directory in which to write postmortem dump files. The default is your home directory.
-m
Don't dump memory.
-n
Save sequential dumps. Each dump is saved in a file whose name is in the form:

executable.num.core

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

-P
Dump the physical memory mappings.
-p pid
Save a dump file for this process immediately, and then exit dumper.
-s size[G|M|K]
Set the maximum core size, in bytes.
-t
Dump the stack of the errant thread only, instead of for all threads.
-v
Be verbose.
-w
Make core files world-readable.
-z level
Use gzip to compress the core files. The compression level must be in the range from 1 (fastest) through 9 (best compressed).

Description:

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 your home directory.


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

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


Note: 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 you specify -p, 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 that 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 &

Files:

/proc/dumper
A special entry in the /proc filesystem (see procnto*) that receives notification when a process terminates abnormally.

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).

See also:

coreinfo, gdb, kill, slay