[systemd-devel] question about BUS_MATCH_ARG_PATH
Hi, All, According to the DBus protocol, http://dbus.freedesktop.org/doc/dbus-specification.html An example argument path match is arg0path='/aa/bb/'. This would match messages with first arguments of '/', '/aa/', '/aa/bb/', '/aa/bb/cc/' and '/aa/bb/cc'. It would not match messages with first arguments of '/aa/b', '/aa' or even '/aa/bb'. Then I did a simple test using the attached test-bus-kernel-bloom.c , and I found that if I used arg0path='/p1/p2/' , the callback function couldn't run when I sent emit signal with '/' , '/p1/' , '/p1/p2/p3'. I traced into the codes , and modified bloom_add_prefixes() , then I can watch the signals with '/p1/p2/p3' , and '/p1/p2/' , but still cannot watch the signals with '/' or '/p1/'. Any recommendations are appreciated. Thanks! Best Regards, Li Cheng ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] siphash24 gives unmatched bloom_mask and bloom_filter?
Hi, David,
I think I've found the reason for my problem. That is , with
arg0path=/p1/p2/p3,
The sent signal should be sent with arg0=/p1/p2/p3/, but not arg0=/p1/p2/p3.
Then Another question is, with arg0path=/p1/p2, the signal sent with
arg0=/p1/p2/p3
should be received and the callback be executed.
But following the execution path: proces_message()== process_match()
==bus_match_run()
== value_node_test() == path_complex_pattern()== complex_pattern_check('/',
pattern, value)
== if (*a != *b) return (separator (*a == 0 || *b == 0)) || (*a == 0 *b
== c b[1] == 0) || (*b == 0 *a == c a[1] == 0);
This will return false, which caused the callback cannot be executed.
Should this comply with the DBus Spec?
Thank you!
David Herrmann Mon, 08 Jun 2015 09:44:25 -0700
Hi
On Mon, Jun 8, 2015 at 3:26 PM, eshar...@163.com wrote:
Hi, David
I just modified the src/libsystemd/sd-bus/test-bus-match.c.
And you could add the following two lines in the bloom_add_data() in
bus-bloom.c
for (i = 0; i size/sizeof(uint64_t); i++)
log_info(bloom: filter[%d] = 0x%llx,i, filter[i]);
Can you please try with systemd-220? The diff against 220 is 83 lines
and it doesn't even compile. If there is a bloom-bug, it should be
possible to show this with a much shorter example. I'm having a hard
time understanding what you changed there, sorry.
Thanks
David___
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Re: [systemd-devel] siphash24 gives unmatched bloom_mask and bloom_filter?
Hi, David
I just modified the src/libsystemd/sd-bus/test-bus-match.c.
And you could add the following two lines in the bloom_add_data() in bus-bloom.c
for (i = 0; i size/sizeof(uint64_t); i++)
log_info(bloom: filter[%d] = 0x%llx,i, filter[i]);
Hi, All,
I use libsystemd.so for the kdbus protocol layer, and I met a
question that I added a signal matching rule by sd_bus_add_match() , then I
sent signal by sd_bus_send().
But I couldn't receive this signal because its bloom_filter caculated by
siphash24() NOT match the bloom_mask which was also caculated by
siphash24().
For example , when adding matching rule for
type='signal',interface='service.a.interface',path='/service/a',member='com_0yunos_0spms_0uninstall',arg0path='/p1/p2/p3'
by sd_bus_add_match(),
Can you provide a real C-code example so we can reproduce this?
Thank you very much!
Li Cheng
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see http://www.gnu.org/licenses/.
***/
#include log.h
#include macro.h
#include bus-match.h
#include bus-message.h
#include bus-util.h
#include bus-slot.h
static bool mask[32];
static int filter(sd_bus *b, sd_bus_message *m, void *userdata, sd_bus_error
*ret_error) {
log_info(Ran %u, PTR_TO_UINT(userdata));
assert_se(PTR_TO_UINT(userdata) ELEMENTSOF(mask));
mask[PTR_TO_UINT(userdata)] = true;
return 0;
}
static bool mask_contains(unsigned a[], unsigned n) {
unsigned i, j;
for (i = 0; i ELEMENTSOF(mask); i++) {
bool found = false;
for (j = 0; j n; j++)
if (a[j] == i) {
found = true;
break;
}
if (found != mask[i])
return false;
}
return true;
}
static int match_add(sd_bus_slot *slots, struct bus_match_node *root, const
char *match, int value) {
struct bus_match_component *components = NULL;
unsigned n_components = 0;
sd_bus_slot *s;
int r;
s = slots + value;
zero(*s);
r = bus_match_parse(match, components, n_components);
if (r 0)
return r;
s-userdata = INT_TO_PTR(value);
s-match_callback.callback = filter;
r = bus_match_add(root, components, n_components, s-match_callback);
bus_match_parse_free(components, n_components);
return r;
}
int main(int argc, char *argv[]) {
struct bus_match_node root = {
.type = BUS_MATCH_ROOT,
};
_cleanup_bus_message_unref_ sd_bus_message *m = NULL;
_cleanup_bus_close_unref_ sd_bus *bus = NULL;
enum bus_match_node_type i;
sd_bus_slot *slots[19];
int r;
r = sd_bus_open_system(bus);
if (r 0)
return EXIT_TEST_SKIP;
//assert_se(match_add(slots, root,
type='signal',interface='service.a.interface',path='/service/a',member='com_0yunos_0spms_0uninstall',arg0path='/p1/p2/p3',,
1) = 0);
assert_se(sd_bus_add_match(bus, slots[1],
type='signal',interface='service.a.interface',path='/service/a',member='com_0yunos_0spms_0uninstall',arg0path='/p1/p2/p3',,
filter, NULL) = 0);
bus_match_dump(bus-match_callbacks, 0);
assert_se(sd_bus_message_new_signal(bus, m, /service/a,
service.a.interface, com_0yunos_0spms_0uninstall) = 0);
// assert_se(sd_bus_message_append(m, s, /p1/p2/p3) = 0);
assert_se(sd_bus_message_append_basic(m, SD_BUS_TYPE_STRING,
/p1/p2/p3) = 0);
//assert_se(bus_message_seal(m, 1, 0) = 0);
assert_se(sd_bus_send(bus, m, NULL) = 0);
bus_match_free(root);
return 0;
}
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[systemd-devel] siphash24 gives unmatched bloom_mask and bloom_filter?
Hi, All, I use libsystemd.so for the kdbus protocol layer, and I met a question that I added a signal matching rule by sd_bus_add_match() , then I sent signal by sd_bus_send(). But I couldn't receive this signal because its bloom_filter caculated by siphash24() NOT match the bloom_mask which was also caculated by siphash24(). For example , when adding matching rule for type='signal',interface='service.a.interface',path='/service/a',member='com_0yunos_0spms_0uninstall',arg0path='/p1/p2/p3' by sd_bus_add_match(), I got the following bloom_mask: bloom: mask[0] = 0x4c0880d4 bloom: mask[1] = 0x880410402010 bloom: mask[2] = 0x4610 bloom: mask[3] = 0x80408 bloom: mask[4] = 0x12000101000 bloom: mask[5] = 0x804822002000 bloom: mask[6] = 0x400040200110 bloom: mask[7] = 0x10 But when I sent the exact same signal by sd_bus_send(), I got the following bloom_filter: bloom: filter[0] = 0x6e0801020086 bloom: filter[1] = 0x880411408410 bloom: filter[2] = 0x2000400c40400710 bloom: filter[3] = 0x20800040528 bloom: filter[4] = 0x120010080002000 bloom: filter[5] = 0x8058000122406000 bloom: filter[6] = 0xc22000104111 bloom: filter[7] = 0x800300a12080 Obviously, filter[0] maks[0] != mask[0], which caused that I couldn't receive the signal. I also tested with type='signal',interface='service.a.interface',path='/service/a',member='com_0yunos_0spms_0uninstall' , which works OK. Could anyone gives me some suggestion? Thanks a lot!___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
