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Diffstat (limited to 'tapset/DEVGUIDE')
| -rw-r--r-- | tapset/DEVGUIDE | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/tapset/DEVGUIDE b/tapset/DEVGUIDE index 693521a8..5d7c8658 100644 --- a/tapset/DEVGUIDE +++ b/tapset/DEVGUIDE @@ -244,6 +244,23 @@ potentially be invalid. If you're not sure, err on the side of caution. The cost of using kread() is small compared to the cost of your tapset inadvertently crashing a system! +Add the string + /* pure */ +into the body of the embedded-C function if it has no side-effects +such as changing external state, so that systemtap could elide +(optimize away) a call to the function if its results are unused. + +Add the string + /* unprivileged */ +into the body of the embedded-C function, only if it is safe for use +by unprivileged users. In general, this requires the function to be +absolutely robust with respect to its inputs, and expose/modify no +information except that belonging to the user's own processes. +(The assert_is_myproc() macro may help enforce this.) Roughly +speaking, it should only perform operations that the same user +could already do from ordinary userspace interfaces. + + Review & Submission ------------------- All new tapsets and major changes should be reviewed "early and often" |