stapbpf(8)

1STAPBPF(8)                  System Manager's Manual                 STAPBPF(8)
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NAME

6       stapbpf - systemtap bpf runtime
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SYNOPSIS

12       stapbpf [ OPTIONS ] MODULE
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DESCRIPTION

16       The  stapbpf  program  is  the  BPF back-end of the Systemtap tool.  It
17       expects a bpf-elf file produced by the front-end stap  tool,  when  run
18       with --runtime=bpf.
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21       Splitting  the  systemtap tool into a front-end and a back-end allows a
22       user to compile a systemtap script on a development  machine  that  has
23       the  debugging information needed to compile the script and then trans‐
24       fer the resulting shared object to a production  machine  that  doesn't
25       have any development tools or debugging information installed.
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27       Please refer to stappaths(7) for the version number, or run
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29        $ rpm -q systemtap # (for Fedora/RHEL)
30        $ apt-get -v systemtap # (for Ubuntu)
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OPTIONS

34       The  stapbpf  program supports the following options.  Any other option
35       prints a list of supported options.
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37       -v     Verbose mode.
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39       -V     Print version number and exit.
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41       -w     Suppress warnings from the script.
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43       -h     Print help message.
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45       -x PID The '_stp_target' variable will be set to PID.
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47       -o FILE
48              Send output to FILE.
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ARGUMENTS

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

57       Here  is  a  very  basic  example  of how to generate a stapbpf module.
58       First, use stap to compile a script.  The stap program will report  the
59       name of the resulting module in the current working directory.
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61         $  stap --runtime=bpf -p4 -e 'probe begin { printf("Hello World!\n");
62       exit() }'
63        stap_28784.bo
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65       Run stapbpf with the pathname to the module as an argument.
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67        $ stapbpf ./stap_28784.bo
68        Hello World!
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70       If the -p4 option is omitted, stap will invoke stapbpf automatically.
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LIMITATIONS

74       This runtime is in an early stage of development and it currently lacks
75       support  for  a number of features available in the default runtime.  A
76       subset of the following probe points is supported:
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79              begin
80              end
81              kernel.*
82              process.*
83              timer.*
84              perf.*
85              procfs.*
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88       In general, probes based on the kprobes, uprobes, tracepoint  and  perf
89       infrastructures  are supported. See stapprobes(3stap) for more informa‐
90       tion on the probe points and which  tracing  infrastructures  they  are
91       based on.
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93       for  loops,  foreach loops and while loops are usable only in begin and
94       end probes.  try statements are not supported.
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96       There is limited support for string operations.  String  variables  and
97       literals  are  limited  to  64  characters,  except  for  printf format
98       strings, which are limited to 256 characters.
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100       A subset of the statistical aggregate functionality is available,  with
101       support only for the @count(), @sum(), @avg() extractor functions.
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103       The name of the bpf-elf file produced by the front-end stap tool should
104       not be changed.
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SAFETY AND SECURITY

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

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