bionic (8) execsnoop-perf.8.gz

NAME

       execsnoop - trace process exec() with arguments. Uses Linux ftrace.

SYNOPSIS

       execsnoop [-hrt] [-a argc] [-d secs] [name]

DESCRIPTION

       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(). With the -r option, it will also catch processes that re-exec. It makes a best-effort attempt  to
       retrieve  the program arguments and PPID; if these are unavailable, 0 and "[?]" are printed respectively.
       There is also a limit to the number of arguments printed (by default, 8), which can  be  increased  using
       -a.

       This  implementation is designed to work on older kernel versions, and without kernel debuginfo. It works
       by dynamic tracing an  execve  kernel  function  to  read  the  arguments  from  the  %si  register.  The
       stub_execve()  function  is  tried first, and then the do_execve() function. The sched:sched_process_fork
       tracepoint, is used for the PPID. Tracing registers and kernel functions is an  unstable  technique,  and
       this tool may not work for some kernels or platforms.

       This  program  is  a  workaround that should be improved in the future when other kernel capabilities are
       made available. If you need a more reliable tool now,  then  consider  other  tracing  alternatives  (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.

REQUIREMENTS

       FTRACE   and  KPROBE  CONFIG,  sched:sched_process_fork  tracepoint,  and  either  the  stub_execve()  or
       do_execve() kernel function. You may already have these on recent kernels. And awk.

OPTIONS

       -a argc
              Maximum number of arguments to show. The default is 8, and the maximum allowed is 16. If execsnoop
              thinks it has truncated the argument list, an ellipsis "[...]" will be shown.

       -d seconds
              Duration to trace, in seconds. This also uses in-kernel buffering.

       -h     Print usage message.

       -r     Include re-exec()s.

       -t     Include timestamps in units of seconds.

       name   Only  show  processes that match this name.  Partials and regular expressions are allowed, as this
              is filtered in user space by awk.

EXAMPLES

       Trace all new processes and arguments (if possible):
              # execsnoop

       Trace all new process names containing the text "http":
              # execsnoop http

FIELDS

       TIMEs  Time of the exec(), in seconds.

       PID    Process ID.

       PPID   Parent process ID, if this was able to be read. If it wasn't, 0 is printed.

       ARGS   Command line arguments, if these were able to be read. If they aren't able to be  read,  "[?]"  is
              printed (which would be due to a limitation in this tools implementation, since this is workaround
              for older kernels; if you need reliable argument tracing, use a different tracer).  They  will  be
              truncated  to  the argc limit, and an ellipsis "[...]" may be printed if execsnoop is aware of the
              truncation.

OVERHEAD

       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.

SOURCE

       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.

OS

       Linux

STABILITY

       Unstable - in development.

AUTHOR

       Brendan Gregg

SEE ALSO

       top(1)