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resolved: fix comments in resolve.conf for search domain overflows (#3422)

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Write comments about "too many search domains" and "Total length of all search
domains is too long" just once. Also put it on a separate line, as
resolv.conf(5) only specifies comments in a line by themselves.

This is ugly to do if write_resolv_conf_search() gets called once for every
search domain. So change it to receive the complete OrderedSet instead and do
the iteration by itself.

Add test cases to networkd-test.py.

https://launchpad.net/bugs/1588229
This commit is contained in:
Martin Pitt 2016-06-03 11:15:44 +02:00 committed by Lennart Poettering
parent 21fce63ecf
commit d2bc125132
2 changed files with 93 additions and 27 deletions
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49
src/resolve/resolved-resolv-conf.c
View File

@ -164,30 +164,32 @@ static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) {
}
static void write_resolv_conf_search(
const char *domain,
FILE *f,
unsigned *count,
unsigned *length) {
OrderedSet *domains,
FILE *f) {
unsigned length = 0, count = 0;
Iterator i;
char *domain;
assert(domain);
assert(domains);
assert(f);
assert(length);
if (*count >= MAXDNSRCH ||
*length + strlen(domain) > 256) {
if (*count == MAXDNSRCH)
fputs(" # Too many search domains configured, remaining ones ignored.", f);
if (*length <= 256)
fputs(" # Total length of all search domains is too long, remaining ones ignored.", f);
fputs("search", f);
return;
ORDERED_SET_FOREACH(domain, domains, i) {
if (++count > MAXDNSRCH) {
fputs("\n# Too many search domains configured, remaining ones ignored.", f);
break;
}
length += strlen(domain) + 1;
if (length > 256) {
fputs("\n# Total length of all search domains is too long, remaining ones ignored.", f);
break;
}
fputc(' ', f);
fputs(domain, f);
}
(*length) += strlen(domain);
(*count)++;
fputc(' ', f);
fputs(domain, f);
fputs("\n", f);
}
static int write_resolv_conf_contents(FILE *f, OrderedSet *dns, OrderedSet *domains) {
@ -209,15 +211,8 @@ static int write_resolv_conf_contents(FILE *f, OrderedSet *dns, OrderedSet *doma
write_resolv_conf_server(s, f, &count);
}
if (!ordered_set_isempty(domains)) {
unsigned length = 0, count = 0;
char *domain;
fputs("search", f);
ORDERED_SET_FOREACH(domain, domains, i)
write_resolv_conf_search(domain, f, &count, &length);
fputs("\n", f);
}
if (!ordered_set_isempty(domains))
write_resolv_conf_search(domains, f);
return fflush_and_check(f);
}

71
test/networkd-test.py
View File

@ -370,6 +370,77 @@ exec $(systemctl cat systemd-networkd.service | sed -n '/^ExecStart=/ { s/^.*=//
def test_coldplug_dhcp_ip6(self):
pass
def test_search_domains(self):
# we don't use this interface for this test
self.if_router = None
with open('/run/systemd/network/test.netdev', 'w') as f:
f.write('''[NetDev]
Name=dummy0
Kind=dummy
MACAddress=12:34:56:78:9a:bc''')
with open('/run/systemd/network/test.network', 'w') as f:
f.write('''[Match]
Name=dummy0
[Network]
Address=192.168.42.100
DNS=192.168.42.1
Domains= one two three four five six seven eight nine ten''')
self.addCleanup(os.remove, '/run/systemd/network/test.netdev')
self.addCleanup(os.remove, '/run/systemd/network/test.network')
subprocess.check_call(['systemctl', 'start', 'systemd-networkd'])
if os.path.islink('/etc/resolv.conf'):
for timeout in range(50):
with open('/etc/resolv.conf') as f:
contents = f.read()
if 'search one\n' in contents:
break
time.sleep(0.1)
self.assertIn('search one two three four five six\n'
'# Too many search domains configured, remaining ones ignored.\n',
contents)
def test_search_domains_too_long(self):
# we don't use this interface for this test
self.if_router = None
name_prefix = 'a' * 60
with open('/run/systemd/network/test.netdev', 'w') as f:
f.write('''[NetDev]
Name=dummy0
Kind=dummy
MACAddress=12:34:56:78:9a:bc''')
with open('/run/systemd/network/test.network', 'w') as f:
f.write('''[Match]
Name=dummy0
[Network]
Address=192.168.42.100
DNS=192.168.42.1
Domains=''')
for i in range(5):
f.write('%s%i ' % (name_prefix, i))
self.addCleanup(os.remove, '/run/systemd/network/test.netdev')
self.addCleanup(os.remove, '/run/systemd/network/test.network')
subprocess.check_call(['systemctl', 'start', 'systemd-networkd'])
if os.path.islink('/etc/resolv.conf'):
for timeout in range(50):
with open('/etc/resolv.conf') as f:
contents = f.read()
if 'search one\n' in contents:
break
time.sleep(0.1)
self.assertIn('search %(p)s0 %(p)s1 %(p)s2 %(p)s3\n'
'# Total length of all search domains is too long, remaining ones ignored.' % {'p': name_prefix},
contents)
if __name__ == '__main__':
unittest.main(testRunner=unittest.TextTestRunner(stream=sys.stdout,