On my Ubuntu installation this removes 15k of duplicate strings,
using a temporary index of about 25k.
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
On Fri, Nov 7, 2008 at 13:07, Matthias Schwarzott <zzam@gentoo.org> wrote:
> I managed to let udev-131 segfault at startup.
>
> I configured it like this:
> CFLAGS="-Wall -ggdb" ./configure --prefix=/usr --sysconfdir=/etc --exec-prefix=
>
> Running it in gdb shows it segfaults at udev-rules.c:831
>
> (gdb) run
> Starting program: /tmp/udev-131/udev/udevd
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x0804ea06 in get_key (udev=0x9175008, line=0xafcdc8f0, key=0xafcdc5d8,
> op=0xafcdc5d0, value=0xafcdc5d4)
> at udev-rules.c:831
> 831 dbg(udev, "%s '%s'-'%s'\n", operation_str[*op], *key, *value);
If compiled without optimization, the dbg() macro dereferences variables
which are not available. Convert the string array to a function, which just
returns NULL if compiled without DEBUG.
I'm worried about what will happen with things like
KERNELS=="*" # pointless rule
KERNELS=="doesnt-match" # another pointless rule
Since TK_RULE < TK_M_PARENTS_MAX, we will try to match all three tokens
against parents of the current device. I can't think of a bad case,
but it's not exactly good either.
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
LAST_RULE was broken, and I broke TK_END by making it do the same.
It used a "break" which exited the switch statement, but not the loop!
==2953== Invalid read of size 4
==2953== at 0x4081EE: dump_token (udev-rules.c:859)
==2953== by 0x40BADB: udev_rules_apply_to_event (udev-rules.c:1849)
==2953== by 0x403F17: udev_event_execute_rules (udev-event.c:554)
==2953== by 0x418626: main (test-udev.c:100)
==2953== Address 0x55ab1f8 is 0 bytes after a block of size 80 alloc'd
==2953== at 0x4C23082: realloc (vg_replace_malloc.c:429)
==2953== by 0x40B13B: udev_rules_new (udev-rules.c:1670)
==2953== by 0x418536: main (test-udev.c:84)
...
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Initializing a char array to "" is equivalent to a memset()
call - which is exactly what it gets compiled to.
Fixing this one callsite reduced memset() _user_ cpu cycles
from 2-4% to 0.05% on the EeePC.
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
This crops up in my threaded udevd profiles from time to time.
It's not consistent - probably due to variations in the number
of concurrent events - but it can hit 4% user time and higher.
The change halves the user time spent in compare_devpath().
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
