1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
|
// 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_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 HANDLER: 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;
// 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;
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;
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);
}
}
// reap_child reaps the child identified by pid.
static void reap_child(pid_t pid) {
siginfo_t i;
errno = 0;
debug(D_CHILDS, "SIGNAL: reap_child(%d)...", pid);
if (netdata_waitid(P_PID, (id_t)pid, &i, WEXITED|WNOHANG) == -1) {
if (errno != ECHILD)
error("SIGNAL: waitid(%d): failed to wait for child", pid);
else
info("SIGNAL: waitid(%d): failed - it seems the child is already reaped", pid);
return;
}
else if (i.si_pid == 0) {
// Process didn't exit, this shouldn't happen.
error("SIGNAL: waitid(%d): reports pid 0 - child has not exited", pid);
return;
}
switch (i.si_code) {
case CLD_EXITED:
info("SIGNAL: reap_child(%d) exited with code: %d", pid, i.si_status);
break;
case CLD_KILLED:
info("SIGNAL: reap_child(%d) killed by signal: %d", pid, i.si_status);
break;
case CLD_DUMPED:
info("SIGNAL: reap_child(%d) dumped core by signal: %d", pid, i.si_status);
break;
case CLD_STOPPED:
info("SIGNAL: reap_child(%d) stopped by signal: %d", pid, i.si_status);
break;
case CLD_TRAPPED:
info("SIGNAL: reap_child(%d) trapped by signal: %d", pid, i.si_status);
break;
case CLD_CONTINUED:
info("SIGNAL: reap_child(%d) continued by signal: %d", pid, i.si_status);
break;
default:
info("SIGNAL: reap_child(%d) gave us a SIGCHLD with code %d and status %d.", pid, i.si_code, i.si_status);
break;
}
}
// reap_children reaps all pending children which are not managed by myp.
static void reap_children() {
siginfo_t i;
while(1) {
i.si_pid = 0;
if (netdata_waitid(P_ALL, (id_t)0, &i, WEXITED|WNOHANG|WNOWAIT) == -1 || i.si_pid == 0)
// nothing to do
return;
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:
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.");
}
}
|
