svn commit: r309589 - head/usr.bin/truss
John Baldwin
jhb at freebsd.org
Tue Dec 6 01:04:32 UTC 2016
On Tuesday, December 06, 2016 12:39:00 AM John Baldwin wrote:
> Author: jhb
> Date: Tue Dec 6 00:39:00 2016
> New Revision: 309589
> URL: https://svnweb.freebsd.org/changeset/base/309589
>
> Log:
> Rework syscall structure lookups.
>
> Avoid always using an O(n^2) loop over known syscall structures with
> strcmp() on each system call. Instead, use a per-ABI cache indexed by
> the system call number. The first 1024 system calls (which should cover
> all of the normal system calls in currently-supported ABIs) use a flat array
> indexed by the system call number to find system call structure. For other
> system calls, a linked list of structures storing an integer to structure
> mapping is stored in the ABI. The linked list isn't very smart, but it
> should only be used by buggy applications invoking unknown system calls.
>
> This also fixes handling of unknown system calls which currently trigger
> a NULL pointer dereference.
>
> Reviewed by: kib
> MFC after: 2 weeks
I of course forgot:
Differential Revision: https://reviews.freebsd.org/D8639
The table + linked-list could perhaps be replaced by a hash table, but
I don't quite feel like writing a new hash table from scratch. One
option would be to make truss a C++ program and use unordered_map<>.
We could then turn the procabi thing into a class which might look a bit
nicer (and use constructors to initialize the hash table instead of
the inline STAILQ_HEAD_INITIALIZER).
--
John Baldwin
More information about the svn-src-all
mailing list