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resolved: split out all code dealing with /etc/resolv.conf into its own .c file

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No functional changes.
This commit is contained in:
Lennart Poettering
2015-11-25 21:58:37 +01:00
parent 636e813dc9
commit f8dc7e343d
6 changed files with 337 additions and 276 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Makefile.am
+2
View File
@@ -5140,6 +5140,8 @@ systemd_resolved_SOURCES = \
src/resolve/resolved-manager.h \
src/resolve/resolved-conf.c \
src/resolve/resolved-conf.h \
src/resolve/resolved-resolv-conf.c \
src/resolve/resolved-resolv-conf.h \
src/resolve/resolved-bus.c \
src/resolve/resolved-bus.h \
src/resolve/resolved-link.h \
src/resolve/resolved-manager.c
+1 -274
View File
@@ -21,7 +21,6 @@
#include <netinet/in.h>
#include <poll.h>
#include <resolv.h>
#include <sys/ioctl.h>
#include "af-list.h"
@@ -40,6 +39,7 @@
#include "resolved-conf.h"
#include "resolved-llmnr.h"
#include "resolved-manager.h"
#include "resolved-resolv-conf.h"
#include "socket-util.h"
#include "string-table.h"
#include "string-util.h"
@@ -579,279 +579,6 @@ Manager *manager_free(Manager *m) {
return NULL;
}
int manager_read_resolv_conf(Manager *m) {
_cleanup_fclose_ FILE *f = NULL;
struct stat st, own;
char line[LINE_MAX];
DnsServer *s;
usec_t t;
int r;
assert(m);
/* Reads the system /etc/resolv.conf, if it exists and is not
* symlinked to our own resolv.conf instance */
if (!m->read_resolv_conf)
return 0;
r = stat("/etc/resolv.conf", &st);
if (r < 0) {
if (errno == ENOENT)
r = 0;
else
r = log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m");
goto clear;
}
/* Have we already seen the file? */
t = timespec_load(&st.st_mtim);
if (t == m->resolv_conf_mtime)
return 0;
m->resolv_conf_mtime = t;
/* Is it symlinked to our own file? */
if (stat("/run/systemd/resolve/resolv.conf", &own) >= 0 &&
st.st_dev == own.st_dev &&
st.st_ino == own.st_ino) {
r = 0;
goto clear;
}
f = fopen("/etc/resolv.conf", "re");
if (!f) {
if (errno == ENOENT)
r = 0;
else
r = log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m");
goto clear;
}
if (fstat(fileno(f), &st) < 0) {
r = log_error_errno(errno, "Failed to stat open file: %m");
goto clear;
}
manager_mark_dns_servers(m, DNS_SERVER_SYSTEM);
FOREACH_LINE(line, f, r = -errno; goto clear) {
_cleanup_strv_free_ char **d = NULL;
const char *a;
char *l;
truncate_nl(line);
l = strstrip(line);
if (*l == '#' || *l == ';')
continue;
a = first_word(l, "nameserver");
if (a) {
r = manager_add_dns_server_by_string(m, DNS_SERVER_SYSTEM, a);
if (r < 0)
log_warning_errno(r, "Failed to parse DNS server address '%s', ignoring.", a);
continue;
}
}
manager_flush_marked_dns_servers(m, DNS_SERVER_SYSTEM);
/* Whenever /etc/resolv.conf changes, start using the first
* DNS server of it. This is useful to deal with broken
* network managing implementations (like NetworkManager),
* that when connecting to a VPN place both the VPN DNS
* servers and the local ones in /etc/resolv.conf. Without
* resetting the DNS server to use back to the first entry we
* will continue to use the local one thus being unable to
* resolve VPN domains. */
manager_set_dns_server(m, m->dns_servers);
return 0;
clear:
while (m->dns_servers) {
s = m->dns_servers;
LIST_REMOVE(servers, m->dns_servers, s);
dns_server_unref(s);
}
return r;
}
static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) {
_cleanup_free_ char *t = NULL;
int r;
assert(s);
assert(f);
assert(count);
r = in_addr_to_string(s->family, &s->address, &t);
if (r < 0) {
log_warning_errno(r, "Invalid DNS address. Ignoring: %m");
return;
}
if (*count == MAXNS)
fputs("# Too many DNS servers configured, the following entries may be ignored.\n", f);
(*count) ++;
fprintf(f, "nameserver %s\n", t);
}
static void write_resolv_conf_search(
const char *domain,
FILE *f,
unsigned *count,
unsigned *length) {
assert(domain);
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);
return;
}
(*length) += strlen(domain);
(*count) ++;
fputc(' ', f);
fputs(domain, f);
}
static int write_resolv_conf_contents(FILE *f, OrderedSet *dns, OrderedSet *domains) {
Iterator i;
fputs("# This file is managed by systemd-resolved(8). Do not edit.\n#\n"
"# Third party programs must not access this file directly, but\n"
"# only through the symlink at /etc/resolv.conf. To manage\n"
"# resolv.conf(5) in a different way, replace the symlink by a\n"
"# static file or a different symlink.\n\n", f);
if (ordered_set_isempty(dns))
fputs("# No DNS servers known.\n", f);
else {
unsigned count = 0;
DnsServer *s;
ORDERED_SET_FOREACH(s, dns, i)
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);
}
return fflush_and_check(f);
}
int manager_write_resolv_conf(Manager *m) {
static const char path[] = "/run/systemd/resolve/resolv.conf";
_cleanup_free_ char *temp_path = NULL;
_cleanup_fclose_ FILE *f = NULL;
_cleanup_ordered_set_free_ OrderedSet *dns = NULL, *domains = NULL;
DnsServer *s;
Iterator i;
Link *l;
int r;
assert(m);
/* Read the system /etc/resolv.conf first */
manager_read_resolv_conf(m);
/* Add the full list to a set, to filter out duplicates */
dns = ordered_set_new(&dns_server_hash_ops);
if (!dns)
return -ENOMEM;
domains = ordered_set_new(&dns_name_hash_ops);
if (!domains)
return -ENOMEM;
/* First add the system-wide servers and domains */
LIST_FOREACH(servers, s, m->dns_servers) {
r = ordered_set_put(dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
/* Then, add the per-link servers and domains */
HASHMAP_FOREACH(l, m->links, i) {
char **domain;
LIST_FOREACH(servers, s, l->dns_servers) {
r = ordered_set_put(dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
if (!l->unicast_scope)
continue;
STRV_FOREACH(domain, l->unicast_scope->domains) {
r = ordered_set_put(domains, *domain);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
/* If we found nothing, add the fallback servers */
if (ordered_set_isempty(dns)) {
LIST_FOREACH(servers, s, m->fallback_dns_servers) {
r = ordered_set_put(dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
r = fopen_temporary_label(path, path, &f, &temp_path);
if (r < 0)
return r;
fchmod(fileno(f), 0644);
r = write_resolv_conf_contents(f, dns, domains);
if (r < 0)
goto fail;
if (rename(temp_path, path) < 0) {
r = -errno;
goto fail;
}
return 0;
fail:
(void) unlink(path);
(void) unlink(temp_path);
return r;
}
int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
union {
src/resolve/resolved-manager.h
-2
View File
@@ -113,8 +113,6 @@ int manager_new(Manager **ret);
Manager* manager_free(Manager *m);
int manager_start(Manager *m);
int manager_read_resolv_conf(Manager *m);
int manager_write_resolv_conf(Manager *m);
DnsServer *manager_set_dns_server(Manager *m, DnsServer *s);
DnsServer *manager_find_dns_server(Manager *m, int family, const union in_addr_union *in_addr);
src/resolve/resolved-resolv-conf.c
+306
View File
@@ -0,0 +1,306 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2014 Tom Gundersen <teg@jklm.no>
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 <resolv.h>
#include "alloc-util.h"
#include "dns-domain.h"
#include "fd-util.h"
#include "fileio-label.h"
#include "fileio.h"
#include "ordered-set.h"
#include "resolved-conf.h"
#include "resolved-resolv-conf.h"
#include "string-util.h"
#include "strv.h"
int manager_read_resolv_conf(Manager *m) {
_cleanup_fclose_ FILE *f = NULL;
struct stat st, own;
char line[LINE_MAX];
DnsServer *s;
usec_t t;
int r;
assert(m);
/* Reads the system /etc/resolv.conf, if it exists and is not
* symlinked to our own resolv.conf instance */
if (!m->read_resolv_conf)
return 0;
r = stat("/etc/resolv.conf", &st);
if (r < 0) {
if (errno == ENOENT)
r = 0;
else
r = log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m");
goto clear;
}
/* Have we already seen the file? */
t = timespec_load(&st.st_mtim);
if (t == m->resolv_conf_mtime)
return 0;
m->resolv_conf_mtime = t;
/* Is it symlinked to our own file? */
if (stat("/run/systemd/resolve/resolv.conf", &own) >= 0 &&
st.st_dev == own.st_dev &&
st.st_ino == own.st_ino) {
r = 0;
goto clear;
}
f = fopen("/etc/resolv.conf", "re");
if (!f) {
if (errno == ENOENT)
r = 0;
else
r = log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m");
goto clear;
}
if (fstat(fileno(f), &st) < 0) {
r = log_error_errno(errno, "Failed to stat open file: %m");
goto clear;
}
manager_mark_dns_servers(m, DNS_SERVER_SYSTEM);
FOREACH_LINE(line, f, r = -errno; goto clear) {
_cleanup_strv_free_ char **d = NULL;
const char *a;
char *l;
truncate_nl(line);
l = strstrip(line);
if (*l == '#' || *l == ';')
continue;
a = first_word(l, "nameserver");
if (a) {
r = manager_add_dns_server_by_string(m, DNS_SERVER_SYSTEM, a);
if (r < 0)
log_warning_errno(r, "Failed to parse DNS server address '%s', ignoring.", a);
continue;
}
}
manager_flush_marked_dns_servers(m, DNS_SERVER_SYSTEM);
/* Whenever /etc/resolv.conf changes, start using the first
* DNS server of it. This is useful to deal with broken
* network managing implementations (like NetworkManager),
* that when connecting to a VPN place both the VPN DNS
* servers and the local ones in /etc/resolv.conf. Without
* resetting the DNS server to use back to the first entry we
* will continue to use the local one thus being unable to
* resolve VPN domains. */
manager_set_dns_server(m, m->dns_servers);
return 0;
clear:
while (m->dns_servers) {
s = m->dns_servers;
LIST_REMOVE(servers, m->dns_servers, s);
dns_server_unref(s);
}
return r;
}
static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) {
_cleanup_free_ char *t = NULL;
int r;
assert(s);
assert(f);
assert(count);
r = in_addr_to_string(s->family, &s->address, &t);
if (r < 0) {
log_warning_errno(r, "Invalid DNS address. Ignoring: %m");
return;
}
if (*count == MAXNS)
fputs("# Too many DNS servers configured, the following entries may be ignored.\n", f);
(*count) ++;
fprintf(f, "nameserver %s\n", t);
}
static void write_resolv_conf_search(
const char *domain,
FILE *f,
unsigned *count,
unsigned *length) {
assert(domain);
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);
return;
}
(*length) += strlen(domain);
(*count) ++;
fputc(' ', f);
fputs(domain, f);
}
static int write_resolv_conf_contents(FILE *f, OrderedSet *dns, OrderedSet *domains) {
Iterator i;
fputs("# This file is managed by systemd-resolved(8). Do not edit.\n#\n"
"# Third party programs must not access this file directly, but\n"
"# only through the symlink at /etc/resolv.conf. To manage\n"
"# resolv.conf(5) in a different way, replace the symlink by a\n"
"# static file or a different symlink.\n\n", f);
if (ordered_set_isempty(dns))
fputs("# No DNS servers known.\n", f);
else {
unsigned count = 0;
DnsServer *s;
ORDERED_SET_FOREACH(s, dns, i)
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);
}
return fflush_and_check(f);
}
int manager_write_resolv_conf(Manager *m) {
static const char path[] = "/run/systemd/resolve/resolv.conf";
_cleanup_free_ char *temp_path = NULL;
_cleanup_fclose_ FILE *f = NULL;
_cleanup_ordered_set_free_ OrderedSet *dns = NULL, *domains = NULL;
DnsServer *s;
Iterator i;
Link *l;
int r;
assert(m);
/* Read the system /etc/resolv.conf first */
manager_read_resolv_conf(m);
/* Add the full list to a set, to filter out duplicates */
dns = ordered_set_new(&dns_server_hash_ops);
if (!dns)
return -ENOMEM;
domains = ordered_set_new(&dns_name_hash_ops);
if (!domains)
return -ENOMEM;
/* First add the system-wide servers and domains */
LIST_FOREACH(servers, s, m->dns_servers) {
r = ordered_set_put(dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
/* Then, add the per-link servers and domains */
HASHMAP_FOREACH(l, m->links, i) {
char **domain;
LIST_FOREACH(servers, s, l->dns_servers) {
r = ordered_set_put(dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
if (!l->unicast_scope)
continue;
STRV_FOREACH(domain, l->unicast_scope->domains) {
r = ordered_set_put(domains, *domain);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
/* If we found nothing, add the fallback servers */
if (ordered_set_isempty(dns)) {
LIST_FOREACH(servers, s, m->fallback_dns_servers) {
r = ordered_set_put(dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
r = fopen_temporary_label(path, path, &f, &temp_path);
if (r < 0)
return r;
fchmod(fileno(f), 0644);
r = write_resolv_conf_contents(f, dns, domains);
if (r < 0)
goto fail;
if (rename(temp_path, path) < 0) {
r = -errno;
goto fail;
}
return 0;
fail:
(void) unlink(path);
(void) unlink(temp_path);
return r;
}
src/resolve/resolved-resolv-conf.h
+27
View File
@@ -0,0 +1,27 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#pragma once
/***
This file is part of systemd.
Copyright 2014 Tom Gundersen <teg@jklm.no>
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 "resolved-manager.h"
int manager_read_resolv_conf(Manager *m);
int manager_write_resolv_conf(Manager *m);
src/resolve/resolved.c
+1
View File
@@ -26,6 +26,7 @@
#include "mkdir.h"
#include "resolved-conf.h"
#include "resolved-manager.h"
#include "resolved-resolv-conf.h"
#include "selinux-util.h"
#include "signal-util.h"
#include "user-util.h"