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

6       staprun - systemtap runtime
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SYNOPSIS

10       staprun [ OPTIONS ] MODULE [ MODULE-OPTIONS ]
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DESCRIPTION

14       The  staprun program is the back-end of the Systemtap tool.  It expects
15       a kernel module produced by the front-end stap tool.
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17       Splitting the systemtap tool into a front-end and a back-end  allows  a
18       user  to  compile  a systemtap script on a development machine that has
19       the kernel development tools (needed to compile the  script)  and  then
20       transfer  the  resulting  kernel  module  to  a production machine that
21       doesn't have any development tools installed.
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23       Please refer to stappaths (7) for the version number,  or  run  rpm  -q
24       systemtap (fedora/red hat) apt-get -v systemtap (ubuntu)
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OPTIONS

28       The  staprun  program supports the following options.  Any other option
29       prints a list of supported options.
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31       -v     Verbose mode. The level of verbosity is also set in the  SYSTEM‐
32              TAP_VERBOSE environment variable.
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34       -V     Print version number and exit.
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36       -w     Suppress warnings from the script.
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38       -u     Load the uprobes.ko module.
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40       -c CMD Command  CMD  will be run and the staprun program will exit when
41              CMD does.  The '_stp_target' variable will contain the  pid  for
42              CMD.
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44       -x PID The '_stp_target' variable will be set to PID.
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46       -o FILE
47              Send  output  to  FILE. If the module uses bulk mode, the output
48              will be in percpu files FILE_x(FILE_cpux in background and  bulk
49              mode)  where  'x'  is  the cpu number. This supports strftime(3)
50              formats for FILE.
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52       -b BUFFER_SIZE
53              The systemtap module will specify a buffer  size.   Setting  one
54              here  will  override  that value. The value should be an integer
55              between 1 and 4095 which be assumed to be the buffer size in MB.
56              That value will be per-cpu if bulk mode is used.
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58       -L     Load  module and start probes, then detach from the module leav‐
59              ing the probes running.  The module can be attached to later  by
60              using the -A option.
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62       -A     Attach to loaded systemtap module.
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64       -C WHEN
65              Control coloring of error messages. WHEN must be either "never",
66              "always", or "auto" (i.e. enable only if at a terminal). If  the
67              option  is  missing, then "auto" is assumed. Colors can be modi‐
68              fied using the SYSTEMTAP_COLORS environment  variable.  See  the
69              stap(1)  manual  page  for more information on syntax and behav‐
70              iour.
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72       -d     Delete a module.  Only detached or unused modules the  user  has
73              permission to access will be deleted. Use "*" (quoted) to delete
74              all unused modules.
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76       -D     Run staprun in background as a daemon and show it's pid.
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78       -R     Rename the module to a unique name before inserting it.
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80       -r N:URI
81              Pass the given number and URI data to the tapset  functions  re‐
82              mote_id() and remote_uri().
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84       -S size[,N]
85              Sets  the  maximum size of output file and the maximum number of
86              output files.  If the size of output file  will  exceed  size  ,
87              systemtap switches output file to the next file. And if the num‐
88              ber of output files exceed N , systemtap removes the oldest out‐
89              put file. You can omit the second argument.
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91       -T timeout
92              Sets  maximum  time reader thread will wait before dumping trace
93              buffer. Value is in ms, default is 200ms. Setting this to a high
94              value decreases number of stapio wake-ups, allowing deeper sleep
95              for embedded platforms. But it impacts interactivity on terminal
96              as  traces  are  dumped  less  often  in case of low throughput.
97              There  is  no  interactivity  or  performance  impact  for  high
98              throughput  as  trace is dumped when buffer is full, before this
99              timeout expires.
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101       var1=val
102              Sets the value of global variable var1 to val. Global  variables
103              contained  within a module are treated as module options and can
104              be set from the staprun command line.
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ARGUMENTS

108       MODULE is either a module path or a module name.  If  it  is  a  module
109       name,  the  module will be looked for in the following directory (where
110       'VERSION' is the output of "uname -r"):
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112              /lib/modules/VERSION/systemtap
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114       Any additional arguments on the command line are passed to the  module.
115       One  use  of  these  additional module arguments is to set the value of
116       global variables declared within the module.
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118        $ stap -p4 -m mod1 -e 'global var1="foo";  probe  begin{printf("%s\n",
119       var1); exit()}'
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121       Running this with an additional module argument:
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123        $ staprun mod1.ko var1="HelloWorld"
124        HelloWorld
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126       Spaces  and  exclamation  marks  currently cannot be passed into global
127       variables this way.
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EXAMPLES

131       See the stapex(3stap) manual page for a collection of sample scripts.
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133       Here is a very basic example of how to use staprun.  First, use stap to
134       compile a script.  The stap program will report the pathname to the re‐
135       sulting module.
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137        $ stap -p4 -e 'probe begin { printf("Hello World!\n"); exit() }'
138        /home/user/.systemtap/cache/85/stap_8553d83f78c_265.ko
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140       Run staprun with the pathname to the module as an argument.
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142        $ staprun /home/user/.systemtap/cache/85/stap_8553d83f78c_265.ko
143        Hello World!
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MODULE DETACHING AND ATTACHING

146       After the staprun program installs a Systemtap kernel module, users can
147       detach  from the kernel module and reattach to it later.  The -L option
148       loads the module and automatically detaches.   Users  can  also  detach
149       from the kernel module interactively by sending the SIGQUIT signal from
150       the keyboard (typically by typing Ctrl-\).
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152       To reattach to a kernel module, the staprun -A option would be used.
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FILE SWITCHING BY SIGNAL

156       After staprun launched the stapio program,  users  can  command  it  to
157       switch  output  file  to  next file when it outputs to file(s) (running
158       staprun with -o option) by sending  a  SIGUSR2  signal  to  the  stapio
159       process.  When  it  receives SIGUSR2, it will switch output file to new
160       file with suffix .N where N is the sequential number.  For example,
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162        $ staprun -o foo ...
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164       outputs trace logs to foo and if it receives SIGUSR2 signal, it switch‐
165       es  output  to  foo.1 file. And receiving SIGUSR2 again, it switches to
166       foo.2 file.
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SAFETY AND SECURITY

170       Systemtap, in the default kernel-module runtime mode, is an administra‐
171       tive  tool.  It exposes kernel internal data structures and potentially
172       private user information.  See the stap(1) manual page  for  additional
173       information on safety and security.
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175       To increase system security, users of systemtap must be root, or in the
176       staprun group in order to execute this setuid staprun program.  A  user
177       may  select a particular privilege level with the stap --privilege= op‐
178       tion, which staprun will later enforce.
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180       stapdev
181              Members of the stapdev group can write and load  script  modules
182              with  root-equivalent  privileges,  without  particular security
183              constraints.  (Many safety constraints remain.)
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185       stapsys
186              Members of the stapsys group have almost all the  privileges  of
187              stapdev, except for guru mode constructs.
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189       staprun
190              Members  only  of  the  stapusr group may any-privileged modules
191              placed into the /lib/modules/VERSION/systemtap by the system ad‐
192              ministrator.
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194       staprun
195              Members  only  of the stapusr group may also write and load low-
196              privilege script modules, which are normally limited to  manipu‐
197              lating  their own processes (and not the kernel nor other users'
198              processes).
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200       Part of the privilege enforcement mechanism may require using  a  stap-
201       server  and  administrative  trust in its cryptographic signer; see the
202       stap-server(8) manual page for a for more information.
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205       On a kernel with FIPS mode enabled, staprun normally refuses to attempt
206       to  load  systemtap-generated  kernel modules.  This is because on some
207       kernels, this results in a panic.  If your kernel includes  corrections
208       such  as  linux commit #002c77a48b47, then you can force staprun to at‐
209       tempt module loads anyway, by setting the  STAP_FIPS_OVERRIDE  environ‐
210       ment variable to any value.
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FILES

214       /lib/modules/VERSION/systemtap
215              If  MODULE  is  a  module name, the module will be looked for in
216              this directory.  Users who are only in the 'stapusr'  group  can
217              install  modules located in this directory.  This directory must
218              be owned by the root user and not be world writable.
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SEE ALSO

222       stap(1), stapprobes(3stap), stap-server(8), stapdyn(8), stapex(3stap)
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BUGS

226       Use the Bugzilla link of the project web  page  or  our  mailing  list.
227       http://sourceware.org/systemtap/, <systemtap@sourceware.org>.
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232                                                                    STAPRUN(8)
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