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[Bug translator/10045] process.syscall(NUM) probes
- From: "fche at redhat dot com" <sourceware-bugzilla at sourceware dot org>
- To: systemtap at sources dot redhat dot com
- Date: 16 Apr 2009 17:42:17 -0000
- Subject: [Bug translator/10045] process.syscall(NUM) probes
- References: <20090408122730.10045.fche@redhat.com>
- Reply-to: sourceware-bugzilla at sourceware dot org
------- Additional Comments From fche at redhat dot com 2009-04-16 17:42 -------
> (1) I wonder if we shouldn't go a bit farther and allow users to specify system
> calls by name, instead of by number. Keeping track of the numbers will be
> difficult for script writers.
It would be OK to encode these into the tapset ...
> [...] For instance, on x86_64, when running a 64-bit executable, the
> syscall number for mmap as shown above is 9. But, when running a 32-bit
> executable on that same x86_64 system, you have to look for either 90 (mmap) or
> 192 (mmap2).
... except for this detail.
If the numbers are run-time variable then we lose the advantage of exposing
them to the compiler to generate a nice switch table from multiple probes.
Maybe a suitable tapset-only hack could be ...
tapset/x86_64/utrace-syscalls.stp:
probe process.syscall.mmap.x86 = process.syscall(90), process.syscall(192) {
if (! task_arch ("i686")) next;
}
probe process.syscall.mmap.x86_64 = process.syscall(9) {
if (! task_arch ("x86_64")) next;
}
probe process.syscall.mmap = process.syscall.mmap.* { }
(For tapset/i686/utrace-syscalls.stp, it would expand only to the first.)
> (2) I also wonder if it would be a good idea to accept a list of numbers (or
> names), like this:
> probe process.syscall(NUM1, NUM2, NUM3) {...}
Probably unnecessary; "probe process.syscall(NUM1), process.syscall(NUM2) {}"
is a reasonable way to express small number of alternatives.
--
http://sourceware.org/bugzilla/show_bug.cgi?id=10045
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