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
|
/***
This file is part of systemd.
Copyright 2016 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/reboot.h>
#include <sys/unistd.h>
#include <sys/wait.h>
#include "fd-util.h"
#include "log.h"
#include "nspawn-stub-pid1.h"
#include "process-util.h"
#include "signal-util.h"
#include "time-util.h"
#include "def.h"
int stub_pid1(void) {
enum {
STATE_RUNNING,
STATE_REBOOT,
STATE_POWEROFF,
} state = STATE_RUNNING;
sigset_t fullmask, oldmask, waitmask;
usec_t quit_usec = USEC_INFINITY;
pid_t pid;
int r;
/* Implements a stub PID 1, that reaps all processes and processes a couple of standard signals. This is useful
* for allowing arbitrary processes run in a container, and still have all zombies reaped. */
assert_se(sigfillset(&fullmask) >= 0);
assert_se(sigprocmask(SIG_BLOCK, &fullmask, &oldmask) >= 0);
pid = fork();
if (pid < 0)
return log_error_errno(errno, "Failed to fork child pid: %m");
if (pid == 0) {
/* Return in the child */
assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) >= 0);
setsid();
return 0;
}
reset_all_signal_handlers();
log_close();
close_all_fds(NULL, 0);
log_open();
rename_process("STUBINIT");
assert_se(sigemptyset(&waitmask) >= 0);
assert_se(sigset_add_many(&waitmask,
SIGCHLD, /* posix: process died */
SIGINT, /* sysv: ctrl-alt-del */
SIGRTMIN+3, /* systemd: halt */
SIGRTMIN+4, /* systemd: poweroff */
SIGRTMIN+5, /* systemd: reboot */
SIGRTMIN+6, /* systemd: kexec */
SIGRTMIN+13, /* systemd: halt */
SIGRTMIN+14, /* systemd: poweroff */
SIGRTMIN+15, /* systemd: reboot */
SIGRTMIN+16, /* systemd: kexec */
-1) >= 0);
/* Note that we ignore SIGTERM (sysv's reexec), SIGHUP (reload), and all other signals here, since we don't
* support reexec/reloading in this stub process. */
for (;;) {
siginfo_t si;
usec_t current_usec;
si.si_pid = 0;
r = waitid(P_ALL, 0, &si, WEXITED|WNOHANG);
if (r < 0) {
r = log_error_errno(errno, "Failed to reap children: %m");
goto finish;
}
current_usec = now(CLOCK_MONOTONIC);
if (si.si_pid == pid || current_usec >= quit_usec) {
/* The child we started ourselves died or we reached a timeout. */
if (state == STATE_REBOOT) { /* dispatch a queued reboot */
(void) reboot(RB_AUTOBOOT);
r = log_error_errno(errno, "Failed to reboot: %m");
goto finish;
} else if (state == STATE_POWEROFF)
(void) reboot(RB_POWER_OFF); /* if this fails, fall back to normal exit. */
if (si.si_pid == pid && si.si_code == CLD_EXITED)
r = si.si_status; /* pass on exit code */
else
r = 255; /* signal, coredump, timeout, … */
goto finish;
}
if (si.si_pid != 0)
/* We reaped something. Retry until there's nothing more to reap. */
continue;
if (quit_usec == USEC_INFINITY)
r = sigwaitinfo(&waitmask, &si);
else {
struct timespec ts;
r = sigtimedwait(&waitmask, &si, timespec_store(&ts, quit_usec - current_usec));
}
if (r < 0) {
if (errno == EINTR) /* strace -p attach can result in EINTR, let's handle this nicely. */
continue;
if (errno == EAGAIN) /* timeout reached */
continue;
r = log_error_errno(errno, "Failed to wait for signal: %m");
goto finish;
}
if (si.si_signo == SIGCHLD)
continue; /* Let's reap this */
if (state != STATE_RUNNING)
continue;
/* Would love to use a switch() statement here, but SIGRTMIN is actually a function call, not a
* constant… */
if (si.si_signo == SIGRTMIN+3 ||
si.si_signo == SIGRTMIN+4 ||
si.si_signo == SIGRTMIN+13 ||
si.si_signo == SIGRTMIN+14)
state = STATE_POWEROFF;
else if (si.si_signo == SIGINT ||
si.si_signo == SIGRTMIN+5 ||
si.si_signo == SIGRTMIN+6 ||
si.si_signo == SIGRTMIN+15 ||
si.si_signo == SIGRTMIN+16)
state = STATE_REBOOT;
else
assert_not_reached("Got unexpected signal");
/* (void) kill_and_sigcont(pid, SIGTERM); */
quit_usec = now(CLOCK_MONOTONIC) + DEFAULT_TIMEOUT_USEC;
}
finish:
_exit(r < 0 ? EXIT_FAILURE : r);
}
|
