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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ARGUMENTS | EXAMPLES | MODULE DETACHING AND ATTACHING | FILE SWITCHING BY SIGNAL | SAFETY AND SECURITY | FILES | SEE ALSO | BUGS | COLOPHON |
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STAPRUN(8) System Manager's Manual STAPRUN(8)
staprun - systemtap runtime
staprun [ OPTIONS ] MODULE [ MODULE-OPTIONS ]
The staprun program is the back-end of the Systemtap tool. It
expects a kernel module produced by the front-end stap tool.
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 kernel development tools (needed to compile the script) and then
transfer the resulting kernel module to a production machine that
doesn't have any development tools installed.
Please refer to stappaths (7) for the version number, or run rpm -q
systemtap (fedora/red hat) apt-get -v systemtap (ubuntu)
The staprun program supports the following options. Any other option
prints a list of supported options.
-v Verbose mode. The level of verbosity is also set in the
SYSTEMTAP_VERBOSE environment variable.
-V Print version number and exit.
-w Suppress warnings from the script.
-u Load the uprobes.ko module.
-c CMD Command CMD will be run and the staprun program will exit when
CMD does. The '_stp_target' variable will contain the pid for
CMD.
-x PID The '_stp_target' variable will be set to PID.
-o FILE
Send output to FILE. If the module uses bulk mode, the output
will be in percpu files FILE_x(FILE_cpux in background and
bulk mode) where 'x' is the cpu number. This supports
strftime(3) formats for FILE.
-b BUFFER_SIZE
The systemtap module will specify a buffer size. Setting one
here will override that value. The value should be an integer
between 1 and 4095 which be assumed to be the buffer size in
MB. That value will be per-cpu if bulk mode is used.
-L Load module and start probes, then detach from the module
leaving the probes running. The module can be attached to
later by using the -A option.
-A Attach to loaded systemtap module.
-C WHEN
Control coloring of error messages. WHEN must be either
"never", "always", or "auto" (i.e. enable only if at a termi‐
nal). If the option is missing, then "auto" is assumed. Colors
can be modified using the SYSTEMTAP_COLORS environment vari‐
able. See the stap(1) manual page for more information on syn‐
tax and behaviour.
-d Delete a module. Only detached or unused modules the user has
permission to access will be deleted. Use "*" (quoted) to
delete all unused modules.
-D Run staprun in background as a daemon and show it's pid.
-R Rename the module to a unique name before inserting it.
-r N:URI
Pass the given number and URI data to the tapset functions re‐
mote_id() and remote_uri().
-S size[,N]
Sets the maximum size of output file and the maximum number of
output files. If the size of output file will exceed size ,
systemtap switches output file to the next file. And if the
number of output files exceed N , systemtap removes the oldest
output file. You can omit the second argument.
-T timeout
Sets maximum time reader thread will wait before dumping trace
buffer. Value is in ms, default is 200ms. Setting this to a
high value decreases number of stapio wake-ups, allowing deep‐
er sleep for embedded platforms. But it impacts interactivity
on terminal as traces are dumped less often in case of low
throughput. There is no interactivity or performance impact
for high throughput as trace is dumped when buffer is full,
before this timeout expires.
var1=val
Sets the value of global variable var1 to val. Global vari‐
ables contained within a module are treated as module options
and can be set from the staprun command line.
MODULE is either a module path or a module name. If it is a module
name, the module will be looked for in the following directory (where
'VERSION' is the output of "uname -r"):
/lib/modules/VERSION/systemtap
Any additional arguments on the command line are passed to the
module. One use of these additional module arguments is to set the
value of global variables declared within the module.
$ stap -p4 -m mod1 -e 'global var1="foo"; probe begin{printf("%s\n",
var1); exit()}'
Running this with an additional module argument:
$ staprun mod1.ko var1="HelloWorld"
HelloWorld
Spaces and exclamation marks currently cannot be passed into global
variables this way.
See the stapex(3stap) manual page for a collection of sample scripts.
Here is a very basic example of how to use staprun. First, use stap
to compile a script. The stap program will report the pathname to
the resulting module.
$ stap -p4 -e 'probe begin { printf("Hello World!\n"); exit() }'
/home/user/.systemtap/cache/85/stap_8553d83f78c_265.ko
Run staprun with the pathname to the module as an argument.
$ staprun /home/user/.systemtap/cache/85/stap_8553d83f78c_265.ko
Hello World!
After the staprun program installs a Systemtap kernel module, users
can detach from the kernel module and reattach to it later. The -L
option loads the module and automatically detaches. Users can also
detach from the kernel module interactively by sending the SIGQUIT
signal from the keyboard (typically by typing Ctrl-\).
To reattach to a kernel module, the staprun -A option would be used.
After staprun launched the stapio program, users can command it to
switch output file to next file when it outputs to file(s) (running
staprun with -o option) by sending a SIGUSR2 signal to the stapio
process. When it receives SIGUSR2, it will switch output file to new
file with suffix .N where N is the sequential number. For example,
$ staprun -o foo ...
outputs trace logs to foo and if it receives SIGUSR2 signal, it
switches output to foo.1 file. And receiving SIGUSR2 again, it
switches to foo.2 file.
Systemtap, in the default kernel-module runtime mode, is an
administrative tool. It exposes kernel internal data structures and
potentially private user information. See the stap(1) manual page
for additional information on safety and security.
To increase system security, users of systemtap must be root, or in
the staprun group in order to execute this setuid staprun program. A
user may select a particular privilege level with the stap
--privilege= option, which staprun will later enforce.
stapdev
Members of the stapdev group can write and load script modules
with root-equivalent privileges, without particular security
constraints. (Many safety constraints remain.)
stapsys
Members of the stapsys group have almost all the privileges of
stapdev, except for guru mode constructs.
staprun
Members only of the stapusr group may any-privileged modules
placed into the /lib/modules/VERSION/systemtap by the system
administrator.
staprun
Members only of the stapusr group may also write and load low-
privilege script modules, which are normally limited to
manipulating their own processes (and not the kernel nor other
users' processes).
Part of the privilege enforcement mechanism may require using a stap-
server and administrative trust in its cryptographic signer; see the
stap-server(8) manual page for a for more information.
On a kernel with FIPS mode enabled, staprun normally refuses to
attempt to load systemtap-generated kernel modules. This is because
on some kernels, this results in a panic. If your kernel includes
corrections such as linux commit #002c77a48b47, then you can force
staprun to attempt module loads anyway, by setting the
STAP_FIPS_OVERRIDE environment variable to any value.
/lib/modules/VERSION/systemtap
If MODULE is a module name, the module will be looked for in
this directory. Users who are only in the 'stapusr' group can
install modules located in this directory. This directory
must be owned by the root user and not be world writable.
stap(1), stapprobes(3stap), stap-server(8), stapdyn(8), stapex(3stap)
Use the Bugzilla link of the project web page or our mailing list.
http://sourceware.org/systemtap/ , <systemtap@sourceware.org>.
This page is part of the systemtap (a tracing and live-system
analysis tool) project. Information about the project can be found
at ⟨https://sourceware.org/systemtap/⟩. If you have a bug report for
this manual page, send it to systemtap@sourceware.org. This page was
obtained from the project's upstream Git repository
⟨git://sourceware.org/git/systemtap.git⟩ on 2018-02-02. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2018-02-01.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not part
of the original manual page), send a mail to man-pages@man7.org
STAPRUN(8)
Pages that refer to this page: stap(1), stap-merge(1), stappaths(7), stapbpf(8), stapdyn(8), stap-server(8)
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