execsnoop (8)

execsnoop [-h] [-n name]

execsnoop traces process execution, showing PID, PPID, and argument details if possible.

This traces exec() from the fork()->exec() sequence, which means it won't catch new processes that only fork(), and, it will catch processes that re-exec. This instruments sched:sched_process_exec without buffering, and then in user-space (this program) reads PPID and process arguments asynchronously from /proc.

If the process traced is very short-lived, this program may miss reading arguments and PPID details. In that case, "<?>" and "?" will be printed respectively.

This program is best-effort (a hack), and should be improved in the future when other kernel capabilities are made available. It may be useful in the meantime. If you need a more reliable tool now, consider other tracing alternates (eg, SystemTap). This tool is really a proof of concept to see what ftrace can currently do.

Since this uses ftrace, only the root user can use this tool.

FTRACE CONFIG and the sched:sched_process_exec tracepoint, which you may already have enabled and available on recent kernels, and Perl.

-n name Only show processes that match this name. This is filtered in user space.

-h

Print usage message.

Trace all new processes and arguments (if possible):

execsnoop

Trace all new processes with process name "sed":

execsnoop -n sed

TIME

Time of process exec(): HH:MM:SS.

PID

Process ID.

PPID

Parent process ID, if this was able to be read (may be missed for short-lived processes). If it is unable to be read, "?" is printed.

ARGS

Command line arguments, if these were able to be read in time (may be missed for short-lived processes). If they are unable to be read, "<?>" is printed.

This reads and processes exec() events in user space as they occur. Since the rate of exec() is expected to be low (< 500/s), the overhead is expected to be small or negligible.

This is from the perf-tools collection.

• https://github.com/brendangregg/perf-tools

Also look under the examples directory for a text file containing example usage, output, and commentary for this tool.

Linux

Unstable - in development.

Brendan Gregg

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