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[Bug tapsets/13451] tapset/nd_syscalls.stp:# FIXME: doesn't handle dup3


http://sourceware.org/bugzilla/show_bug.cgi?id=13451

David Smith <dsmith at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dsmith at redhat dot com
         Depends on|                            |11424

--- Comment #1 from David Smith <dsmith at redhat dot com> 2011-11-30 16:36:12 UTC ---
Here's a bit more from tapset/syscalls.stp:

----
# dup3 (handles both dup2 and dup3 except for corner case)___________           
# long sys_dup2(unsigned int oldfd, unsigned int newfd)                         
# SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)   
probe syscall.dup2 = kernel.function("sys_dup3").call !,                        
                     kernel.function("sys_dup2").call                           
----

The reason why it is done this way is that in the kernel sys_dup2 sets a few
things up then calls sys_dup3.  This way we ignore the sys_dup2 call, and only
catch the sys_dup3 call.

Unfortunately, as bug #11424 notes, '!' (optional and sufficient) doesn't work
for kprobe.function probes.  So, the above logic will be difficult to duplicate
in tapset/nd_syscalls.stp.

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