| Directory: | cvmfs/ |
|---|---|
| File: | cvmfs/resolv_conf_event_handler.cc |
| Date: | 2025-06-22 02:36:02 |
| Exec | Total | Coverage | |
|---|---|---|---|
| Lines: | 19 | 51 | 37.3% |
| Branches: | 26 | 64 | 40.6% |
| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /** | ||
| 2 | * This file is part of the CernVM File System. | ||
| 3 | */ | ||
| 4 | |||
| 5 | #include "resolv_conf_event_handler.h" | ||
| 6 | |||
| 7 | #include <string> | ||
| 8 | #include <vector> | ||
| 9 | |||
| 10 | #include "backoff.h" | ||
| 11 | #include "util/logging.h" | ||
| 12 | #include "util/string.h" | ||
| 13 | |||
| 14 | namespace { | ||
| 15 | |||
| 16 | /** | ||
| 17 | * Get the first address of type address_type from the list of addresses | ||
| 18 | * | ||
| 19 | * @param address_list List of IP addresses | ||
| 20 | * @param address_type Type of IP address desired; Can be either 4 or 6 | ||
| 21 | * @param address (out) The first address found | ||
| 22 | */ | ||
| 23 | ✗ | bool GetFirstAddress(const ResolvConfEventHandler::AddressList &address_list, | |
| 24 | int address_type, std::string *address) { | ||
| 25 | ✗ | bool found = false; | |
| 26 | |||
| 27 | ✗ | for (size_t i = 0u; i < address_list.size(); ++i) { | |
| 28 | ✗ | if (address_list[i].first == address_type) { | |
| 29 | ✗ | *address = address_list[i].second; | |
| 30 | ✗ | found = true; | |
| 31 | ✗ | break; | |
| 32 | } | ||
| 33 | } | ||
| 34 | ✗ | return found; | |
| 35 | } | ||
| 36 | |||
| 37 | } // namespace | ||
| 38 | |||
| 39 | ✗ | ResolvConfEventHandler::ResolvConfEventHandler( | |
| 40 | download::DownloadManager *download_manager, | ||
| 41 | ✗ | download::DownloadManager *external_download_manager) | |
| 42 | ✗ | : download_manager_(download_manager) | |
| 43 | ✗ | , external_download_manager_(external_download_manager) { } | |
| 44 | |||
| 45 | ✗ | ResolvConfEventHandler::~ResolvConfEventHandler() { } | |
| 46 | |||
| 47 | ✗ | bool ResolvConfEventHandler::Handle(const std::string &file_path, | |
| 48 | file_watcher::Event /*event*/, | ||
| 49 | bool *clear_handler) { | ||
| 50 | ✗ | AddressList addresses; | |
| 51 | ✗ | GetDnsAddresses(file_path, &addresses); | |
| 52 | ✗ | if (!addresses.empty()) { | |
| 53 | ✗ | SetDnsAddress(download_manager_, addresses); | |
| 54 | ✗ | SetDnsAddress(external_download_manager_, addresses); | |
| 55 | } | ||
| 56 | ✗ | *clear_handler = false; | |
| 57 | ✗ | return true; | |
| 58 | } | ||
| 59 | |||
| 60 | /** | ||
| 61 | * Returns any nameserver IP addresses from file | ||
| 62 | * | ||
| 63 | * Reads a file, line by line. Returns the IP addresses corresponding | ||
| 64 | * to nameservers (i.e. from lines "nameserver <IP_ADDRESS>") | ||
| 65 | */ | ||
| 66 | 56 | void ResolvConfEventHandler::GetDnsAddresses(const std::string &resolv_file, | |
| 67 | AddressList *addresses) { | ||
| 68 | 56 | bool done = false; | |
| 69 |
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56 | BackoffThrottle throttle(100, 1000, 5000); |
| 70 |
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112 | while (!done) { |
| 71 |
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56 | FILE *f = std::fopen(resolv_file.c_str(), "r"); |
| 72 |
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56 | if (!f) { |
| 73 | ✗ | LogCvmfs(kLogCvmfs, kLogDebug, | |
| 74 | "ResolvConfEventHandler - Could not open: %s", | ||
| 75 | resolv_file.c_str()); | ||
| 76 | ✗ | throttle.Throttle(); | |
| 77 | ✗ | continue; | |
| 78 | } | ||
| 79 | 56 | std::string line; | |
| 80 |
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210 | while (GetLineFile(f, &line)) { |
| 81 |
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154 | std::vector<std::string> key_val = SplitString(line, ' '); |
| 82 |
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154 | if (key_val.size() == 2 && key_val[0] == "nameserver") { |
| 83 | // We have found a nameserver line | ||
| 84 |
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98 | if (SplitString(key_val[1], '.').size() == 4) { |
| 85 | // This looks like an IPv4 address | ||
| 86 |
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42 | addresses->push_back(std::make_pair(4, key_val[1])); |
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56 | } else if (SplitString(key_val[1], ':').size() == 8) { |
| 88 | // This looks like an IPv6 address | ||
| 89 |
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28 | addresses->push_back(std::make_pair(6, key_val[1])); |
| 90 | } | ||
| 91 | } | ||
| 92 | 154 | } | |
| 93 |
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56 | std::fclose(f); |
| 94 | 56 | done = true; | |
| 95 | 56 | } | |
| 96 | 56 | } | |
| 97 | |||
| 98 | ✗ | void ResolvConfEventHandler::SetDnsAddress( | |
| 99 | download::DownloadManager *download_manager, const AddressList &addresses) { | ||
| 100 | // Default to IPv4 addresses unless kIpPreferV6 is specified | ||
| 101 | ✗ | const int address_type = download_manager->opt_ip_preference() | |
| 102 | == dns::kIpPreferV6 | ||
| 103 | ✗ | ? 6 | |
| 104 | ✗ | : 4; | |
| 105 | |||
| 106 | ✗ | std::string new_address; | |
| 107 | ✗ | if (GetFirstAddress(addresses, address_type, &new_address)) { | |
| 108 | ✗ | LogCvmfs(kLogCvmfs, kLogDebug, | |
| 109 | "ResolvConfEventhandler - resolv.conf file changed. " | ||
| 110 | "Setting new DNS address: %s", | ||
| 111 | new_address.c_str()); | ||
| 112 | ✗ | download_manager->SetDnsServer(new_address); | |
| 113 | } | ||
| 114 | } | ||
| 115 |