Adding upstream version 1.29.3.upstream/1.29.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 285 insertions, 0 deletions

diff --git a/daemon/signals.c b/daemon/signals.c
new file mode 100644
index 0000000..9e30bf1
--- /dev/null
+++ b/daemon/signals.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "common.h"
+
+static int reaper_enabled = 0;
+
+typedef enum signal_action {
+    NETDATA_SIGNAL_END_OF_LIST,
+    NETDATA_SIGNAL_IGNORE,
+    NETDATA_SIGNAL_EXIT_CLEANLY,
+    NETDATA_SIGNAL_SAVE_DATABASE,
+    NETDATA_SIGNAL_REOPEN_LOGS,
+    NETDATA_SIGNAL_RELOAD_HEALTH,
+    NETDATA_SIGNAL_FATAL,
+    NETDATA_SIGNAL_CHILD,
+} 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_REOPEN_LOGS   },
+        { SIGUSR1, "SIGUSR1", 0, NETDATA_SIGNAL_SAVE_DATABASE },
+        { SIGUSR2, "SIGUSR2", 0, NETDATA_SIGNAL_RELOAD_HEALTH },
+        { SIGBUS,  "SIGBUS",  0, NETDATA_SIGNAL_FATAL         },
+        { SIGCHLD, "SIGCHLD", 0, NETDATA_SIGNAL_CHILD         },
+
+        // 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 complain 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;
+
+    // Enable process tracking / reaper if running as init (pid == 1).
+    // This prevents zombie processes when running in a container.
+    if (getpid() == 1) {
+        info("SIGNAL: Enabling reaper");
+        myp_init();
+        reaper_enabled = 1;
+    } else {
+        info("SIGNAL: Not enabling reaper");
+    }
+
+    // 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++) {
+        switch (signals_waiting[i].action) {
+        case NETDATA_SIGNAL_IGNORE:
+            sa.sa_handler = SIG_IGN;
+            break;
+        case NETDATA_SIGNAL_CHILD:
+            if (reaper_enabled == 0)
+                continue;
+            // FALLTHROUGH
+        default:
+            sa.sa_handler = signal_handler;
+            break;
+        }
+
+        if(sigaction(signals_waiting[i].signo, &sa, NULL) == -1)
+            error("SIGNAL: Failed to change signal handler for: %s", signals_waiting[i].name);
+    }
+}
+
+void signals_restore_SIGCHLD(void)
+{
+    struct sigaction sa;
+
+    if (reaper_enabled == 0)
+        return;
+
+    sa.sa_flags = 0;
+    sigfillset(&sa.sa_mask);
+    sa.sa_handler = signal_handler;
+
+    if(sigaction(SIGCHLD, &sa, NULL) == -1)
+        error("SIGNAL: Failed to change signal handler for: SIGCHLD");
+}
+
+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);
+    }
+
+    if (reaper_enabled == 1)
+        myp_free();
+}
+
+// reap_child reaps the child identified by pid.
+static void reap_child(pid_t pid) {
+    siginfo_t i;
+
+    errno = 0;
+    debug(D_CHILDS, "SIGNAL: Reaping pid: %d...", pid);
+    if (waitid(P_PID, (id_t)pid, &i, WEXITED|WNOHANG) == -1) {
+        if (errno != ECHILD)
+            error("SIGNAL: Failed to wait for: %d", pid);
+        else
+            debug(D_CHILDS, "SIGNAL: Already reaped: %d", pid);
+        return;
+    } else if (i.si_pid == 0) {
+        // Process didn't exit, this shouldn't happen.
+        return;
+    }
+
+    switch (i.si_code) {
+    case CLD_EXITED:
+        debug(D_CHILDS, "SIGNAL: Child %d exited: %d", pid, i.si_status);
+        break;
+    case CLD_KILLED:
+        debug(D_CHILDS, "SIGNAL: Child %d killed by signal: %d", pid, i.si_status);
+        break;
+    case CLD_DUMPED:
+        debug(D_CHILDS, "SIGNAL: Child %d dumped core by signal: %d", pid, i.si_status);
+        break;
+    case CLD_STOPPED:
+        debug(D_CHILDS, "SIGNAL: Child %d stopped by signal: %d", pid, i.si_status);
+        break;
+    case CLD_TRAPPED:
+        debug(D_CHILDS, "SIGNAL: Child %d trapped by signal: %d", pid, i.si_status);
+        break;
+    case CLD_CONTINUED:
+        debug(D_CHILDS, "SIGNAL: Child %d continued by signal: %d", pid, i.si_status);
+        break;
+    default:
+        debug(D_CHILDS, "SIGNAL: Child %d gave us a SIGCHLD with code %d and status %d.", pid, i.si_code, i.si_status);
+    }
+}
+
+// reap_children reaps all pending children which are not managed by myp.
+static void reap_children() {
+    siginfo_t i;
+
+    while (1 == 1) {
+        // Identify which process caused the signal so we can determine
+        // if we need to reap a re-parented process.
+        i.si_pid = 0;
+        if (waitid(P_ALL, (id_t)0, &i, WEXITED|WNOHANG|WNOWAIT) == -1) {
+            if (errno != ECHILD) // This shouldn't happen with WNOHANG but does.
+                error("SIGNAL: Failed to wait");
+            return;
+        } else if (i.si_pid == 0) {
+            // No child exited.
+            return;
+        } else if (myp_reap(i.si_pid) == 0) {
+            // myp managed, sleep for a short time to avoid busy wait while
+            // this is handled by myp.
+            usleep(10000);
+        } else {
+            // Unknown process, likely a re-parented child, reap it.
+            reap_child(i.si_pid);
+        }
+    }
+}
+
+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);
+                                error_log_limit_reset();
+                                execute_command(CMD_RELOAD_HEALTH, NULL, NULL);
+                                break;
+
+                            case NETDATA_SIGNAL_SAVE_DATABASE:
+                                error_log_limit_unlimited();
+                                info("SIGNAL: Received %s. Saving databases...", name);
+                                error_log_limit_reset();
+                                execute_command(CMD_SAVE_DATABASE, NULL, NULL);
+                                break;
+
+                            case NETDATA_SIGNAL_REOPEN_LOGS:
+                                error_log_limit_unlimited();
+                                info("SIGNAL: Received %s. Reopening all log files...", name);
+                                error_log_limit_reset();
+                                execute_command(CMD_REOPEN_LOGS, NULL, NULL);
+                                break;
+
+                            case NETDATA_SIGNAL_EXIT_CLEANLY:
+                                error_log_limit_unlimited();
+                                info("SIGNAL: Received %s. Cleaning up to exit...", name);
+                                commands_exit();
+                                netdata_cleanup_and_exit(0);
+                                exit(0);
+                                break;
+
+                            case NETDATA_SIGNAL_FATAL:
+                                fatal("SIGNAL: Received %s. netdata now exits.", name);
+                                break;
+
+                            case NETDATA_SIGNAL_CHILD:
+                                debug(D_CHILDS, "SIGNAL: Received %s. Reaping...", name);
+                                reap_children();
+                                break;
+
+                            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.");
+    }
+}