NAME

       stapbpf - systemtap bpf runtime

SYNOPSIS

       stapbpf [ OPTIONS ] MODULE

DESCRIPTION

       The  stapbpf program is the BPF back-end of the Systemtap tool.  It expects a bpf-elf file
       produced by the front-end stap tool, when run with --runtime=bpf.

       Splitting the systemtap tool into a front-end and a back-end allows a user  to  compile  a
       systemtap  script  on  a  development machine that has the debugging information needed to
       compile the script and then transfer the resulting shared object to a  production  machine
       that doesn't have any development tools or debugging information installed.

       Please refer to stappaths(7) for the version number, or run

        $ rpm -q systemtap # (for Fedora/RHEL)
        $ apt-get -v systemtap # (for Ubuntu)

OPTIONS

       The  stapbpf  program  supports  the following options.  Any other option prints a list of
       supported options.

       -v     Verbose mode.

       -V     Print version number and exit.

       -w     Suppress warnings from the script.

       -h     Print help message.

       -x PID The '_stp_target' variable will be set to PID.

       -o FILE
              Send output to FILE.

ARGUMENTS

       MODULE is the path of a bpf-elf file produced by the front-end stap tool,  when  run  with
       --runtime=bpf.

EXAMPLES

       Here  is  a  very  basic  example of how to generate a stapbpf module.  First, use stap to
       compile a script.  The stap program will report the name of the resulting  module  in  the
       current working directory.

        $ stap --runtime=bpf -p4 -e 'probe begin { printf("Hello World!\n"); exit() }'
        stap_28784.bo

       Run stapbpf with the pathname to the module as an argument.

        $ stapbpf ./stap_28784.bo
        Hello World!

       If the -p4 option is omitted, stap will invoke stapbpf automatically.

LIMITATIONS

       This  runtime  is  in  an  early stage of development and it currently lacks support for a
       number of features available in the default runtime.  A  subset  of  the  following  probe
       points is supported:

              begin
              end
              kernel.*
              process.*
              timer.*
              perf.*
              procfs.*

       In  general, probes based on the kprobes, uprobes, tracepoint and perf infrastructures are
       supported. See stapprobes(3stap) for more  information  on  the  probe  points  and  which
       tracing infrastructures they are based on.

       for  loops,  foreach  loops  and while loops are usable only in begin and end probes.  try
       statements are not supported.

       There is limited support for string operations. String variables and literals are  limited
       to 64 characters, except for printf format strings, which are limited to 256 characters.

       A  subset  of  the statistical aggregate functionality is available, with support only for
       the @count(), @sum(), @avg() extractor functions.

       The name of the bpf-elf file produced by the front-end stap tool should not be changed.

SAFETY AND SECURITY

       See the stap(1) manual page for additional information on safety and security.

SEE ALSO

       stap(1), stapprobes(3stap), staprun(8), stapex(3stap)

BUGS

       Use   the   Bugzilla   link   of   the   project   web   page   or   our   mailing   list.
       http://sourceware.org/systemtap/, <systemtap@sourceware.org>.

                                                                                       STAPBPF(8)