NAME¶

timelimit — effectively limit the absolute execution time of a process

SYNOPSIS¶

DESCRIPTION¶

The timelimit utility executes a given command with the supplied arguments and terminates the spawned process after a given time with a given signal. If the process exits before the time limit has elapsed, timelimit will silently exit, too.

Options:

--features

List the compile-time features supported by this version of timelimit:

timelimit

Always present, with the version of the timelimit tool.

subsecond

Present if timeouts with subsecond precision are supported, with version 1.0.

-p

If the child process is terminated by a signal, timelimit propagates this condition, i.e. sends the same signal to itself. This allows the program executing timelimit to determine whether the child process was terminated by a signal or actually exited with an exit code larger than 128.

-q

Quiet operation - timelimit does not output diagnostic messages about signals sent to the child process.

-S killsig

Specify the number of the signal to be sent to the process killtime seconds after warntime has expired. Defaults to 9 (SIGKILL).

-s warnsig

Specify the number of the signal to be sent to the process warntime seconds after it has been started. Defaults to 15 (SIGTERM).

-T killtime

Specify the maximum execution time of the process before sending killsig after warnsig has been sent. Defaults to 120 seconds.

-t warntime

Specify the maximum execution time of the process in seconds before sending warnsig. Defaults to 3600 seconds.

On systems that support the setitimer(2) system call, the warntime and killtime values may be specified in fractional seconds with microsecond precision.

ENVIRONMENT¶

KILLSIG

The killsig to use if the -S option was not specified.

KILLTIME

The killtime to use if the -T option was not specified.

WARNSIG

The warnsig to use if the -s option was not specified.

WARNTIME

The warntime to use if the -t option was not specified.

EXIT STATUS¶

If the child process exits normally, the timelimit utility will pass its exit code on up. If the child process is terminated by a signal and the -p flag was not specified, the timelimit utility's exit status is 128 plus the signal number, similar to sh(1). If the -p flag was specified, the timelimit utility will raise the signal itself so that its own parent process may in turn reliably distinguish between a signal and a larger than 128 exit code.

In rare cases, the timelimit utility may encounter a system or user error; then, its exit status is one of the standard sysexits(3) values:

EX_USAGE

The command-line parameters and options were incorrectly specified.

EX_SOFTWARE

The timelimit utility itself received an unexpected signal while waiting for the child process to terminate.

EX_OSERR

The timelimit utility was unable to execute the child process, wait for it to terminate, or examine its exit status.

EXAMPLES¶

The following examples are shown as given to the shell:

Run the rsync program to mirror a WWW or FTP site and kill it if it runs longer than 1 hour (that is 3600 seconds) with SIGTERM. If the rsync process does not exit after receiving the SIGTERM, timelimit issues a SIGKILL 120 seconds after the SIGTERM. If the rsync process is terminated by a signal, timelimit will itself raise this signal.

Start a tcpserver(n) process listening on tcp port 8888; each client connection shall invoke an instance of an IRC statistics tool under /opt/services/chat and kill it after 600 seconds have elapsed. If the stats process is still running after the SIGTERM, it will be killed by a SIGKILL sent 300 seconds later.

Start a shell script and kill it with a SIGHUP in a little under 5 seconds. If the shell gets stuck and does not respond to the SIGHUP, kill it with the default SIGKILL just a bit over a second afterwards.

SEE ALSO¶

kill(1), rsync(1), signal(3), tcpserver(n)

STANDARDS¶

No standards documentation was harmed in the process of creating timelimit.

BUGS¶

Please report any bugs in timelimit to the author.

AUTHOR¶

The timelimit utility was conceived and written by Peter Pentchev ⟨roam@ringlet.net⟩ with contributions and suggestions by Karsten W Rohrbach ⟨karsten@rohrbach.de⟩, Teddy Hogeborn ⟨teddy@fukt.bsnet.se⟩, and Tomasz Nowak ⟨nowak2000@poczta.onet.pl⟩.