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
|
#include "common.h"
/*
struct mypopen {
pid_t pid;
FILE *fp;
struct mypopen *next;
struct mypopen *prev;
};
static struct mypopen *mypopen_root = NULL;
static void mypopen_add(FILE *fp, pid_t *pid) {
struct mypopen *mp = malloc(sizeof(struct mypopen));
if(!mp) {
fatal("Cannot allocate %zu bytes", sizeof(struct mypopen))
return;
}
mp->fp = fp;
mp->pid = pid;
mp->next = popen_root;
mp->prev = NULL;
if(mypopen_root) mypopen_root->prev = mp;
mypopen_root = mp;
}
static void mypopen_del(FILE *fp) {
struct mypopen *mp;
for(mp = mypopen_root; mp; mp = mp->next)
if(mp->fd == fp) break;
if(!mp) error("Cannot find mypopen() file pointer in open childs.");
else {
if(mp->next) mp->next->prev = mp->prev;
if(mp->prev) mp->prev->next = mp->next;
if(mypopen_root == mp) mypopen_root = mp->next;
free(mp);
}
}
*/
#define PIPE_READ 0
#define PIPE_WRITE 1
FILE *mypopen(const char *command, pid_t *pidptr)
{
int pipefd[2];
if(pipe(pipefd) == -1) return NULL;
int pid = fork();
if(pid == -1) {
close(pipefd[PIPE_READ]);
close(pipefd[PIPE_WRITE]);
return NULL;
}
if(pid != 0) {
// the parent
*pidptr = pid;
close(pipefd[PIPE_WRITE]);
FILE *fp = fdopen(pipefd[PIPE_READ], "r");
/*mypopen_add(fp, pid);*/
return(fp);
}
// the child
// close all files
int i;
for(i = (int) (sysconf(_SC_OPEN_MAX) - 1); i > 0; i--)
if(i != STDIN_FILENO && i != STDERR_FILENO && i != pipefd[PIPE_WRITE]) close(i);
// move the pipe to stdout
if(pipefd[PIPE_WRITE] != STDOUT_FILENO) {
dup2(pipefd[PIPE_WRITE], STDOUT_FILENO);
close(pipefd[PIPE_WRITE]);
}
#ifdef DETACH_PLUGINS_FROM_NETDATA
// this was an attempt to detach the child and use the suspend mode charts.d
// unfortunatelly it does not work as expected.
// fork again to become session leader
pid = fork();
if(pid == -1)
error("pre-execution of command '%s' on pid %d: Cannot fork 2nd time.", command, getpid());
if(pid != 0) {
// the parent
exit(0);
}
// set a new process group id for just this child
if( setpgid(0, 0) != 0 )
error("pre-execution of command '%s' on pid %d: Cannot set a new process group.", command, getpid());
if( getpgid(0) != getpid() )
error("pre-execution of command '%s' on pid %d: Cannot set a new process group. Process group set is incorrect. Expected %d, found %d", command, getpid(), getpid(), getpgid(0));
if( setsid() != 0 )
error("pre-execution of command '%s' on pid %d: Cannot set session id.", command, getpid());
fprintf(stdout, "MYPID %d\n", getpid());
fflush(NULL);
#endif
// reset all signals
{
sigset_t sigset;
sigfillset(&sigset);
if(pthread_sigmask(SIG_UNBLOCK, &sigset, NULL) == -1)
error("pre-execution of command '%s' on pid %d: could not unblock signals for threads.", command, getpid());
// We only need to reset ignored signals.
// Signals with signal handlers are reset by default.
struct sigaction sa;
sigemptyset(&sa.sa_mask);
sa.sa_handler = SIG_DFL;
sa.sa_flags = 0;
if(sigaction(SIGINT, &sa, NULL) == -1)
error("pre-execution of command '%s' on pid %d: failed to set default signal handler for SIGINT.", command, getpid());
if(sigaction(SIGTERM, &sa, NULL) == -1)
error("pre-execution of command '%s' on pid %d: failed to set default signal handler for SIGTERM.", command, getpid());
if(sigaction(SIGPIPE, &sa, NULL) == -1)
error("pre-execution of command '%s' on pid %d: failed to set default signal handler for SIGPIPE.", command, getpid());
if(sigaction(SIGHUP, &sa, NULL) == -1)
error("pre-execution of command '%s' on pid %d: failed to set default signal handler for SIGHUP.", command, getpid());
if(sigaction(SIGUSR1, &sa, NULL) == -1)
error("pre-execution of command '%s' on pid %d: failed to set default signal handler for SIGUSR1.", command, getpid());
if(sigaction(SIGUSR2, &sa, NULL) == -1)
error("pre-execution of command '%s' on pid %d: failed to set default signal handler for SIGUSR2.", command, getpid());
}
info("executing command: '%s' on pid %d.", command, getpid());
execl("/bin/sh", "sh", "-c", command, NULL);
exit(1);
}
int mypclose(FILE *fp, pid_t pid) {
debug(D_EXIT, "Request to mypclose() on pid %d", pid);
/*mypopen_del(fp);*/
// close the pipe fd
// this is required in musl
// without it the childs do not exit
close(fileno(fp));
// close the pipe file pointer
fclose(fp);
siginfo_t info;
if(waitid(P_PID, (id_t) pid, &info, WEXITED) != -1) {
switch(info.si_code) {
case CLD_EXITED:
if(info.si_status)
error("child pid %d exited with code %d.", info.si_pid, info.si_status);
return(info.si_status);
break;
case CLD_KILLED:
error("child pid %d killed by signal %d.", info.si_pid, info.si_status);
return(-1);
break;
case CLD_DUMPED:
error("child pid %d core dumped by signal %d.", info.si_pid, info.si_status);
return(-2);
break;
case CLD_STOPPED:
error("child pid %d stopped by signal %d.", info.si_pid, info.si_status);
return(0);
break;
case CLD_TRAPPED:
error("child pid %d trapped by signal %d.", info.si_pid, info.si_status);
return(-4);
break;
case CLD_CONTINUED:
error("child pid %d continued by signal %d.", info.si_pid, info.si_status);
return(0);
break;
default:
error("child pid %d gave us a SIGCHLD with code %d and status %d.", info.si_pid, info.si_code, info.si_status);
return(-5);
break;
}
}
else
error("Cannot waitid() for pid %d", pid);
return 0;
}
|
