| 1 | /* |
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| 2 | * Helper application which monitors network state and checks |
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| 3 | * the reachability of either pool.ntp.org or the host given |
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| 4 | * as the first argument. |
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| 5 | */ |
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| 6 | |
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| 7 | #include <CoreFoundation/CoreFoundation.h> |
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| 8 | #include <SystemConfiguration/SystemConfiguration.h> |
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| 9 | #include <syslog.h> |
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| 10 | |
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| 11 | static void ntpReachabilityCallback (SCNetworkReachabilityRef target, |
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| 12 | SCNetworkConnectionFlags flags, |
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| 13 | void *info); |
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| 14 | |
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| 15 | int main (int argc, const char * argv[]) |
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| 16 | { |
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| 17 | const char ntp_pool[] = "pool.ntp.org"; |
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| 18 | const char *observed_host; |
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| 19 | if (argc > 1) |
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| 20 | observed_host = argv[1]; |
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| 21 | else |
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| 22 | observed_host = ntp_pool; |
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| 23 | |
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| 24 | openlog ("chrony-netchanged", LOG_CONS | LOG_PID, LOG_DAEMON); |
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| 25 | |
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| 26 | SCNetworkReachabilityRef observedHost = SCNetworkReachabilityCreateWithName (NULL, observed_host); |
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| 27 | |
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| 28 | if (observedHost == NULL) |
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| 29 | { |
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| 30 | syslog (LOG_ERR, "Error creating reachability reference."); |
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| 31 | goto bail; |
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| 32 | } |
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| 33 | |
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| 34 | if (!SCNetworkReachabilitySetCallback(observedHost, ntpReachabilityCallback, NULL)) |
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| 35 | { |
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| 36 | syslog (LOG_ERR, "Unable to set reachability callback."); |
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| 37 | goto bail; |
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| 38 | } |
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| 39 | |
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| 40 | if (!SCNetworkReachabilityScheduleWithRunLoop(observedHost, CFRunLoopGetCurrent(), kCFRunLoopCommonModes)) |
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| 41 | { |
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| 42 | syslog (LOG_ERR, "Unable to schedule run loop monitoring on run loop."); |
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| 43 | goto bail; |
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| 44 | } |
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| 45 | |
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| 46 | syslog (LOG_NOTICE, "Observing %s.", observed_host); |
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| 47 | |
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| 48 | CFRunLoopRun (); |
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| 49 | |
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| 50 | bail: |
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| 51 | if (observedHost) |
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| 52 | CFRelease (observedHost); |
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| 53 | |
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| 54 | closelog(); |
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| 55 | |
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| 56 | return EXIT_FAILURE; |
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| 57 | } |
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| 58 | |
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| 59 | static void ntpReachabilityCallback(SCNetworkReachabilityRef target, |
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| 60 | SCNetworkConnectionFlags flags, |
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| 61 | void *info) |
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| 62 | { |
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| 63 | if ((flags & kSCNetworkFlagsReachable) && !(flags & kSCNetworkFlagsConnectionRequired)) |
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| 64 | { |
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| 65 | syslog (LOG_NOTICE, "Link is online. Signalling chronyd to start sampling servers."); |
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| 66 | system (PREFIX "/etc/chrony/chrony-netchange online"); |
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| 67 | } |
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| 68 | else |
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| 69 | { |
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| 70 | syslog (LOG_NOTICE, "Link is offline. Signalling chronyd to stop sampling servers."); |
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| 71 | system (PREFIX "/etc/chrony/chrony-netchange offline"); |
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| 72 | } |
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| 73 | } |
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