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authorDaniel Baumann <daniel.baumann@progress-linux.org>2019-10-26 08:29:10 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2019-10-26 08:29:10 +0000
commit66ae4baad173098544603718e9864f0da1c0c7a3 (patch)
treed8e6f387ee9b4d9b6936e3c21208e50b86daea60 /daemon/signals.c
parentAdding upstream version 1.18.0. (diff)
downloadnetdata-66ae4baad173098544603718e9864f0da1c0c7a3.tar.xz
netdata-66ae4baad173098544603718e9864f0da1c0c7a3.zip
Adding upstream version 1.18.1.upstream/1.18.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'daemon/signals.c')
-rw-r--r--daemon/signals.c103
1 files changed, 100 insertions, 3 deletions
diff --git a/daemon/signals.c b/daemon/signals.c
index 71f271887..5378b04e5 100644
--- a/daemon/signals.c
+++ b/daemon/signals.c
@@ -2,6 +2,8 @@
#include "common.h"
+static int reaper_enabled = 0;
+
typedef enum signal_action {
NETDATA_SIGNAL_END_OF_LIST,
NETDATA_SIGNAL_IGNORE,
@@ -10,6 +12,7 @@ typedef enum signal_action {
NETDATA_SIGNAL_LOG_ROTATE,
NETDATA_SIGNAL_RELOAD_HEALTH,
NETDATA_SIGNAL_FATAL,
+ NETDATA_SIGNAL_CHILD,
} SIGNAL_ACTION;
static struct {
@@ -26,6 +29,7 @@ static struct {
{ 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 }
@@ -42,7 +46,7 @@ static void signal_handler(int signo) {
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
+ // nothing to do - we cannot write but there is no way to complain about it
;
}
}
@@ -74,15 +78,33 @@ void signals_init(void) {
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++) {
- if(signals_waiting[i].action == NETDATA_SIGNAL_IGNORE)
+ switch (signals_waiting[i].action) {
+ case NETDATA_SIGNAL_IGNORE:
sa.sa_handler = SIG_IGN;
- else
+ 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);
@@ -100,6 +122,76 @@ void signals_reset(void) {
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) {
@@ -157,6 +249,11 @@ void signals_handle(void) {
case NETDATA_SIGNAL_FATAL:
fatal("SIGNAL: Received %s. netdata now exits.", name);
+ 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;