diff options
Diffstat (limited to 'daemon/signals.c')
| -rw-r--r-- | daemon/signals.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/daemon/signals.c b/daemon/signals.c new file mode 100644 index 00000000..71f27188 --- /dev/null +++ b/daemon/signals.c @@ -0,0 +1,171 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#include "common.h" + +typedef enum signal_action { + NETDATA_SIGNAL_END_OF_LIST, + NETDATA_SIGNAL_IGNORE, + NETDATA_SIGNAL_EXIT_CLEANLY, + NETDATA_SIGNAL_SAVE_DATABASE, + NETDATA_SIGNAL_LOG_ROTATE, + NETDATA_SIGNAL_RELOAD_HEALTH, + NETDATA_SIGNAL_FATAL, +} SIGNAL_ACTION; + +static struct { + int signo; // the signal + const char *name; // the name of the signal + size_t count; // the number of signals received + SIGNAL_ACTION action; // the action to take +} signals_waiting[] = { + { SIGPIPE, "SIGPIPE", 0, NETDATA_SIGNAL_IGNORE }, + { SIGINT , "SIGINT", 0, NETDATA_SIGNAL_EXIT_CLEANLY }, + { SIGQUIT, "SIGQUIT", 0, NETDATA_SIGNAL_EXIT_CLEANLY }, + { SIGTERM, "SIGTERM", 0, NETDATA_SIGNAL_EXIT_CLEANLY }, + { SIGHUP, "SIGHUP", 0, NETDATA_SIGNAL_LOG_ROTATE }, + { SIGUSR1, "SIGUSR1", 0, NETDATA_SIGNAL_SAVE_DATABASE }, + { SIGUSR2, "SIGUSR2", 0, NETDATA_SIGNAL_RELOAD_HEALTH }, + { SIGBUS, "SIGBUS", 0, NETDATA_SIGNAL_FATAL }, + + // terminator + { 0, "NONE", 0, NETDATA_SIGNAL_END_OF_LIST } +}; + +static void signal_handler(int signo) { + // find the entry in the list + int i; + for(i = 0; signals_waiting[i].action != NETDATA_SIGNAL_END_OF_LIST ; i++) { + if(unlikely(signals_waiting[i].signo == signo)) { + signals_waiting[i].count++; + + if(signals_waiting[i].action == NETDATA_SIGNAL_FATAL) { + char buffer[200 + 1]; + snprintfz(buffer, 200, "\nSIGNAL HANLDER: received: %s. Oops! This is bad!\n", signals_waiting[i].name); + if(write(STDERR_FILENO, buffer, strlen(buffer)) == -1) { + // nothing to do - we cannot write but there is no way to complaint about it + ; + } + } + + return; + } + } +} + +void signals_block(void) { + sigset_t sigset; + sigfillset(&sigset); + + if(pthread_sigmask(SIG_BLOCK, &sigset, NULL) == -1) + error("SIGNAL: Could not block signals for threads"); +} + +void signals_unblock(void) { + sigset_t sigset; + sigfillset(&sigset); + + if(pthread_sigmask(SIG_UNBLOCK, &sigset, NULL) == -1) { + error("SIGNAL: Could not unblock signals for threads"); + } +} + +void signals_init(void) { + // Catch signals which we want to use + struct sigaction sa; + sa.sa_flags = 0; + + // ignore all signals while we run in a signal handler + sigfillset(&sa.sa_mask); + + int i; + for (i = 0; signals_waiting[i].action != NETDATA_SIGNAL_END_OF_LIST; i++) { + if(signals_waiting[i].action == NETDATA_SIGNAL_IGNORE) + sa.sa_handler = SIG_IGN; + else + sa.sa_handler = signal_handler; + + if(sigaction(signals_waiting[i].signo, &sa, NULL) == -1) + error("SIGNAL: Failed to change signal handler for: %s", signals_waiting[i].name); + } +} + +void signals_reset(void) { + struct sigaction sa; + sigemptyset(&sa.sa_mask); + sa.sa_handler = SIG_DFL; + sa.sa_flags = 0; + + int i; + for (i = 0; signals_waiting[i].action != NETDATA_SIGNAL_END_OF_LIST; i++) { + if(sigaction(signals_waiting[i].signo, &sa, NULL) == -1) + error("SIGNAL: Failed to reset signal handler for: %s", signals_waiting[i].name); + } +} + +void signals_handle(void) { + while(1) { + + // pause() causes the calling process (or thread) to sleep until a signal + // is delivered that either terminates the process or causes the invocation + // of a signal-catching function. + if(pause() == -1 && errno == EINTR) { + + // loop once, but keep looping while signals are coming in + // this is needed because a few operations may take some time + // so we need to check for new signals before pausing again + int found = 1; + while(found) { + found = 0; + + // execute the actions of the signals + int i; + for (i = 0; signals_waiting[i].action != NETDATA_SIGNAL_END_OF_LIST; i++) { + if (signals_waiting[i].count) { + found = 1; + signals_waiting[i].count = 0; + const char *name = signals_waiting[i].name; + + switch (signals_waiting[i].action) { + case NETDATA_SIGNAL_RELOAD_HEALTH: + error_log_limit_unlimited(); + info("SIGNAL: Received %s. Reloading HEALTH configuration...", name); + health_reload(); + error_log_limit_reset(); + break; + + case NETDATA_SIGNAL_SAVE_DATABASE: + error_log_limit_unlimited(); + info("SIGNAL: Received %s. Saving databases...", name); + rrdhost_save_all(); + info("Databases saved."); + error_log_limit_reset(); + break; + + case NETDATA_SIGNAL_LOG_ROTATE: + error_log_limit_unlimited(); + info("SIGNAL: Received %s. Reopening all log files...", name); + reopen_all_log_files(); + error_log_limit_reset(); + break; + + case NETDATA_SIGNAL_EXIT_CLEANLY: + error_log_limit_unlimited(); + info("SIGNAL: Received %s. Cleaning up to exit...", name); + netdata_cleanup_and_exit(0); + exit(0); + + case NETDATA_SIGNAL_FATAL: + fatal("SIGNAL: Received %s. netdata now exits.", name); + + default: + info("SIGNAL: Received %s. No signal handler configured. Ignoring it.", name); + break; + } + } + } + } + } + else + error("SIGNAL: pause() returned but it was not interrupted by a signal."); + } +} |