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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "net/base/dns_reloader.h" | 5 #include "net/base/dns_reloader.h" |
6 | 6 |
7 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_OPENBSD) | 7 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_OPENBSD) && \ |
| 8 !defined(OS_ANDROID) |
8 | 9 |
9 #include <resolv.h> | 10 #include <resolv.h> |
10 | 11 |
11 #include "base/basictypes.h" | 12 #include "base/basictypes.h" |
12 #include "base/lazy_instance.h" | 13 #include "base/lazy_instance.h" |
13 #include "base/logging.h" | 14 #include "base/logging.h" |
14 #include "base/message_loop.h" | 15 #include "base/message_loop.h" |
15 #include "base/synchronization/lock.h" | 16 #include "base/synchronization/lock.h" |
16 #include "base/threading/thread_local_storage.h" | 17 #include "base/threading/thread_local_storage.h" |
17 #include "net/base/network_change_notifier.h" | 18 #include "net/base/network_change_notifier.h" |
18 | 19 |
19 namespace { | 20 namespace { |
20 | 21 |
21 // On Linux/BSD, changes to /etc/resolv.conf can go unnoticed thus resulting | 22 // On Linux/BSD, changes to /etc/resolv.conf can go unnoticed thus resulting |
22 // in DNS queries failing either because nameservers are unknown on startup | 23 // in DNS queries failing either because nameservers are unknown on startup |
23 // or because nameserver info has changed as a result of e.g. connecting to | 24 // or because nameserver info has changed as a result of e.g. connecting to |
24 // a new network. Some distributions patch glibc to stat /etc/resolv.conf | 25 // a new network. Some distributions patch glibc to stat /etc/resolv.conf |
25 // to try to automatically detect such changes but these patches are not | 26 // to try to automatically detect such changes but these patches are not |
26 // universal and even patched systems such as Jaunty appear to need calls | 27 // universal and even patched systems such as Jaunty appear to need calls |
27 // to res_ninit to reload the nameserver information in different threads. | 28 // to res_ninit to reload the nameserver information in different threads. |
28 // | 29 // |
29 // To fix this, on systems with FilePathWatcher support, we use | 30 // To fix this, on systems with FilePathWatcher support, we use |
30 // NetworkChangeNotifier::DNSObserver to monitor /etc/resolv.conf to | 31 // NetworkChangeNotifier::DNSObserver to monitor /etc/resolv.conf to |
31 // enable us to respond to DNS changes and reload the resolver state. | 32 // enable us to respond to DNS changes and reload the resolver state. |
32 // | 33 // |
33 // OpenBSD does not have thread-safe res_ninit/res_nclose so we can't do | 34 // OpenBSD does not have thread-safe res_ninit/res_nclose so we can't do |
34 // the same trick there and most *BSD's don't yet have support for | 35 // the same trick there and most *BSD's don't yet have support for |
35 // FilePathWatcher (but perhaps the new kqueue mac code just needs to be | 36 // FilePathWatcher (but perhaps the new kqueue mac code just needs to be |
36 // ported to *BSD to support that). | 37 // ported to *BSD to support that). |
| 38 // |
| 39 // Android does not have /etc/resolv.conf. The system takes care of nameserver |
| 40 // changes, so none of this is needed. |
37 | 41 |
38 class DnsReloader : public net::NetworkChangeNotifier::DNSObserver { | 42 class DnsReloader : public net::NetworkChangeNotifier::DNSObserver { |
39 public: | 43 public: |
40 struct ReloadState { | 44 struct ReloadState { |
41 int resolver_generation; | 45 int resolver_generation; |
42 }; | 46 }; |
43 | 47 |
44 // NetworkChangeNotifier::OnDNSChanged methods: | 48 // NetworkChangeNotifier::OnDNSChanged methods: |
45 virtual void OnDNSChanged() OVERRIDE { | 49 virtual void OnDNSChanged() OVERRIDE { |
46 DCHECK_EQ(MessageLoop::current()->type(), MessageLoop::TYPE_IO); | 50 DCHECK_EQ(MessageLoop::current()->type(), MessageLoop::TYPE_IO); |
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112 } | 116 } |
113 | 117 |
114 void DnsReloaderMaybeReload() { | 118 void DnsReloaderMaybeReload() { |
115 // This routine can be called by any of the DNS worker threads. | 119 // This routine can be called by any of the DNS worker threads. |
116 DnsReloader* dns_reloader = g_dns_reloader.Pointer(); | 120 DnsReloader* dns_reloader = g_dns_reloader.Pointer(); |
117 dns_reloader->MaybeReload(); | 121 dns_reloader->MaybeReload(); |
118 } | 122 } |
119 | 123 |
120 } // namespace net | 124 } // namespace net |
121 | 125 |
122 #endif // defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_OPENBSD) | 126 #endif // defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_OPENBSD) && |
| 127 // !defined(OS_ANDROID) |
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