X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsd_watchdog_enabled.xml;h=653f347ebfc41ee0af889891f113d80e2cbbf75d;hp=462d7c66176c6a26775eb58416df1c7156ae0152;hb=91d60274701a12d2bbcd2b8e40f8b8abe00be0e7;hpb=a9becdd65bb4b64675bc0c109d14ab12b1ecd2b7 diff --git a/man/sd_watchdog_enabled.xml b/man/sd_watchdog_enabled.xml index 462d7c661..653f347eb 100644 --- a/man/sd_watchdog_enabled.xml +++ b/man/sd_watchdog_enabled.xml @@ -1,189 +1,169 @@ + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> - - - sd_watchdog_enabled - systemd - - - - Developer - Lennart - Poettering - lennart@poettering.net - - - - - - sd_watchdog_enabled - 3 - - - - sd_watchdog_enabled - Check whether the service manager expects watchdog keep-alive notifications from a service - - - - - #include <systemd/sd-daemon.h> - - - int sd_watchdog_enabled - int unset_environment - uint64_t *usec - - - - - - Description - sd_watchdog_enabled() may - be called by a service to detect whether the service - manager expects regular keep-alive watchdog - notification events from it, and the timeout after - which the manager will act on the service if it did - not get such a notification. - - If the $WATCHDOG_USEC - environment variable is set, and the - $WATCHDOG_PID variable is unset or - set to the PID of the current process, the service - manager expects notifications from this process. The - manager will usually terminate a service when it does - not get a notification message within the specified - time after startup and after each previous message. It - is recommended that a daemon sends a keep-alive - notification message to the service manager every half - of the time returned here. Notification messages may - be sent with - sd_notify3 - with a message string of - WATCHDOG=1. - - If the unset_environment - parameter is non-zero, - sd_watchdog_enabled() will unset - the $WATCHDOG_USEC and - $WATCHDOG_PID environment variables - before returning (regardless of whether the function - call itself succeeded or not). Those variables are no - longer inherited by child processes. Further calls to - sd_watchdog_enabled() will also - return with zero. - - If the usec parameter is - non-NULL, sd_watchdog_enabled() - will write the timeout in µs for the watchdog - logic to it. - - To enable service supervision with the watchdog - logic, use WatchdogSec= in service - files. See - systemd.service5 - for details. - - - - Return Value - - On failure, this call returns a negative - errno-style error code. If the service manager expects - watchdog keep-alive notification messages to be sent, - > 0 is returned, otherwise 0 is returned. Only if - the return value is > 0, the - usec parameter is valid after - the call. - - - - Notes - - - - Internally, this functions parses the - $WATCHDOG_PID and - $WATCHDOG_USEC environment - variable. The call will ignore these variables if - $WATCHDOG_PID does containe the PID - of the current process, under the assumption that in - that case, the variables were set for a different - process further up the process tree. - - - - Environment - - - - $WATCHDOG_PID - - Set by the system - manager for supervised process for - which watchdog support is enabled, and - contains the PID of that process. See - above for details. - - - - $WATCHDOG_USEC - - Set by the system - manager for supervised process for - which watchdog support is enabled, and - contains the watchdog timeout in µs - See above for - details. - - - - - - History - - The watchdog functionality and the - $WATCHDOG_USEC variable were - added in systemd-41. - - sd_watchdog_enabled() - function was added in systemd-209. Since that version - the $WATCHDOG_PID variable is also - set. - - - - See Also - - systemd1, - sd-daemon3, - daemon7, - systemd.service5, - sd_notify3 - - + xmlns:xi="http://www.w3.org/2001/XInclude"> + + + sd_watchdog_enabled + elogind + + + + Developer + Lennart + Poettering + lennart@poettering.net + + + + + + sd_watchdog_enabled + 3 + + + + sd_watchdog_enabled + Check whether the service manager expects watchdog keep-alive notifications from a service + + + + + #include <elogind/sd-daemon.h> + + + int sd_watchdog_enabled + int unset_environment + uint64_t *usec + + + + + + Description + sd_watchdog_enabled() may be called by + a service to detect whether the service manager expects regular + keep-alive watchdog notification events from it, and the timeout + after which the manager will act on the service if it did not get + such a notification. + + If the $WATCHDOG_USEC environment + variable is set, and the $WATCHDOG_PID variable + is unset or set to the PID of the current process, the service + manager expects notifications from this process. The manager will + usually terminate a service when it does not get a notification + message within the specified time after startup and after each + previous message. It is recommended that a daemon sends a + keep-alive notification message to the service manager every half + of the time returned here. Notification messages may be sent with + sd_notify3 + with a message string of WATCHDOG=1. + + If the unset_environment parameter is + non-zero, sd_watchdog_enabled() will unset + the $WATCHDOG_USEC and + $WATCHDOG_PID environment variables before + returning (regardless of whether the function call itself + succeeded or not). Those variables are no longer inherited by + child processes. Further calls to + sd_watchdog_enabled() will also return with + zero. + + If the usec parameter is non-NULL, + sd_watchdog_enabled() will write the timeout + in µs for the watchdog logic to it. + + To enable service supervision with the watchdog logic, use + WatchdogSec= in service files. See + systemd.service5 + for details. + + Use + sd_event_set_watchdog3 + to enable automatic watchdog support in + sd-event3-based event loops. + + + + Return Value + + On failure, this call returns a negative errno-style error + code. If the service manager expects watchdog keep-alive + notification messages to be sent, > 0 is returned, otherwise 0 + is returned. Only if the return value is > 0, the + usec parameter is valid after the + call. + + + + Notes + + + + Internally, this function parses the + $WATCHDOG_PID and + $WATCHDOG_USEC environment variable. The call + will ignore these variables if $WATCHDOG_PID + does not contain the PID of the current process, under the + assumption that in that case, the variables were set for a + different process further up the process tree. + + + + Environment + + + + $WATCHDOG_PID + + Set by the system manager for supervised + process for which watchdog support is enabled, and contains + the PID of that process. See above for + details. + + + + $WATCHDOG_USEC + + Set by the system manager for supervised + process for which watchdog support is enabled, and contains + the watchdog timeout in µs. See above for + details. + + + + + + See Also + + systemd1, + sd-daemon3, + daemon7, + systemd.service5, + sd_notify3, + sd_event_set_watchdog3 + +