| Summary: | c++ string access tapset | ||
|---|---|---|---|
| Product: | systemtap | Reporter: | William Cohen <wcohen> |
| Component: | tapsets | Assignee: | William Cohen <wcohen> |
| Status: | NEW --- | ||
| Severity: | normal | CC: | fche |
| Priority: | P2 | ||
| Version: | unspecified | ||
| Target Milestone: | --- | ||
| Host: | Target: | ||
| Build: | Last reconfirmed: | ||
There are differences between f28 and rhel7, so needed something like the following on rhel7 for the code to work.
// Dig through C++ string private fields to find the systemtap script name
cmdline_script = @cast(session, "struct systemtap_session")->cmdline_script->_M_dataplus->_M_p
if (strlen(user_string2(cmdline_script, "<unavailable>"))){
script = "<cmdline_script>"
} else {
script_file = @cast(session, "struct systemtap_session")->script_file->_M_dataplus->_M_p
script = user_string2(script_file, "<unavailable>")
}
|
The systemtap example script stap_time.stp needed to access C++ strings provided inside the session variable to get the script name. $ stap -L "stap.pass*" stap.pass0 session:long $arg1:long stap.pass1a session:long $arg1:long stap.pass1b session:long $arg1:long stap.pass2 session:long $arg1:long stap.pass3 session:long $arg1:long stap.pass4 session:long $arg1:long stap.pass5 session:long $arg1:long stap.pass6 session:long $arg1:long Ended up with some ugly code like the following snippet to implement this: len = @cast(session, "struct systemtap_session")->script_file->_M_string_length if (len <= 15) { script_file = @cast(session, "struct systemtap_session")->script_file->_M_local_buf } else { script_file = @cast(session, "struct systemtap_session")->script_file->_M_dataplus->_M_p } There should be c++ string tapset like the existing access to traditional C strings user_string() et al.