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systemd/src/initctl.c
Lennart Poettering f632a6634d initctl: don't use dbus connection after PID 1 got respawned 
After reexec PID 1 our bus connection is invalidated. Hence don't try to
reuse it, just terminate so that when we are spawned the next time we
just get a new one.

Spotted by Marti Raudsepp.
2011-11-01 18:21:32 +01:00

452 lines
13 KiB
C
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/socket.h>
#include <sys/types.h>
#include <assert.h>
#include <time.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <sys/poll.h>
#include <sys/epoll.h>
#include <sys/un.h>
#include <fcntl.h>
#include <ctype.h>
#include <dbus/dbus.h>
#include "util.h"
#include "log.h"
#include "list.h"
#include "initreq.h"
#include "special.h"
#include "sd-daemon.h"
#include "dbus-common.h"
#include "def.h"
#define SERVER_FD_MAX 16
#define TIMEOUT_MSEC ((int) (DEFAULT_EXIT_USEC/USEC_PER_MSEC))
typedef struct Fifo Fifo;
typedef struct Server {
int epoll_fd;
LIST_HEAD(Fifo, fifos);
unsigned n_fifos;
DBusConnection *bus;
bool quit;
} Server;
struct Fifo {
Server *server;
int fd;
struct init_request buffer;
size_t bytes_read;
LIST_FIELDS(Fifo, fifo);
};
static const char *translate_runlevel(int runlevel, bool *isolate) {
static const struct {
const int runlevel;
const char *special;
bool isolate;
} table[] = {
{ '0', SPECIAL_POWEROFF_TARGET, false },
{ '1', SPECIAL_RESCUE_TARGET, true },
{ 's', SPECIAL_RESCUE_TARGET, true },
{ 'S', SPECIAL_RESCUE_TARGET, true },
{ '2', SPECIAL_RUNLEVEL2_TARGET, true },
{ '3', SPECIAL_RUNLEVEL3_TARGET, true },
{ '4', SPECIAL_RUNLEVEL4_TARGET, true },
{ '5', SPECIAL_RUNLEVEL5_TARGET, true },
{ '6', SPECIAL_REBOOT_TARGET, false },
};
unsigned i;
assert(isolate);
for (i = 0; i < ELEMENTSOF(table); i++)
if (table[i].runlevel == runlevel) {
*isolate = table[i].isolate;
if (runlevel == '6' && kexec_loaded())
return SPECIAL_KEXEC_TARGET;
return table[i].special;
}
return NULL;
}
static void change_runlevel(Server *s, int runlevel) {
const char *target;
DBusMessage *m = NULL, *reply = NULL;
DBusError error;
const char *mode;
bool isolate = false;
assert(s);
dbus_error_init(&error);
if (!(target = translate_runlevel(runlevel, &isolate))) {
log_warning("Got request for unknown runlevel %c, ignoring.", runlevel);
goto finish;
}
if (isolate)
mode = "isolate";
else
mode = "replace";
log_debug("Running request %s/start/%s", target, mode);
if (!(m = dbus_message_new_method_call("org.freedesktop.systemd1", "/org/freedesktop/systemd1", "org.freedesktop.systemd1.Manager", "StartUnit"))) {
log_error("Could not allocate message.");
goto finish;
}
if (!dbus_message_append_args(m,
DBUS_TYPE_STRING, &target,
DBUS_TYPE_STRING, &mode,
DBUS_TYPE_INVALID)) {
log_error("Could not attach target and flag information to message.");
goto finish;
}
if (!(reply = dbus_connection_send_with_reply_and_block(s->bus, m, -1, &error))) {
log_error("Failed to start unit: %s", bus_error_message(&error));
goto finish;
}
finish:
if (m)
dbus_message_unref(m);
if (reply)
dbus_message_unref(reply);
dbus_error_free(&error);
}
static void request_process(Server *s, const struct init_request *req) {
assert(s);
assert(req);
if (req->magic != INIT_MAGIC) {
log_error("Got initctl request with invalid magic. Ignoring.");
return;
}
switch (req->cmd) {
case INIT_CMD_RUNLVL:
if (!isprint(req->runlevel))
log_error("Got invalid runlevel. Ignoring.");
else
switch (req->runlevel) {
/* we are async anyway, so just use kill for reexec/reload */
case 'u':
case 'U':
if (kill(1, SIGTERM) < 0)
log_error("kill() failed: %m");
/* The bus connection will be
* terminated if PID 1 is reexecuted,
* hence let's just exit here, and
* rely on that we'll be restarted on
* the next request */
s->quit = true;
break;
case 'q':
case 'Q':
if (kill(1, SIGHUP) < 0)
log_error("kill() failed: %m");
break;
default:
change_runlevel(s, req->runlevel);
}
return;
case INIT_CMD_POWERFAIL:
case INIT_CMD_POWERFAILNOW:
case INIT_CMD_POWEROK:
log_warning("Received UPS/power initctl request. This is not implemented in systemd. Upgrade your UPS daemon!");
return;
case INIT_CMD_CHANGECONS:
log_warning("Received console change initctl request. This is not implemented in systemd.");
return;
case INIT_CMD_SETENV:
case INIT_CMD_UNSETENV:
log_warning("Received environment initctl request. This is not implemented in systemd.");
return;
default:
log_warning("Received unknown initctl request. Ignoring.");
return;
}
}
static int fifo_process(Fifo *f) {
ssize_t l;
assert(f);
errno = EIO;
if ((l = read(f->fd, ((uint8_t*) &f->buffer) + f->bytes_read, sizeof(f->buffer) - f->bytes_read)) <= 0) {
if (errno == EAGAIN)
return 0;
log_warning("Failed to read from fifo: %s", strerror(errno));
return -1;
}
f->bytes_read += l;
assert(f->bytes_read <= sizeof(f->buffer));
if (f->bytes_read == sizeof(f->buffer)) {
request_process(f->server, &f->buffer);
f->bytes_read = 0;
}
return 0;
}
static void fifo_free(Fifo *f) {
assert(f);
if (f->server) {
assert(f->server->n_fifos > 0);
f->server->n_fifos--;
LIST_REMOVE(Fifo, fifo, f->server->fifos, f);
}
if (f->fd >= 0) {
if (f->server)
epoll_ctl(f->server->epoll_fd, EPOLL_CTL_DEL, f->fd, NULL);
close_nointr_nofail(f->fd);
}
free(f);
}
static void server_done(Server *s) {
assert(s);
while (s->fifos)
fifo_free(s->fifos);
if (s->epoll_fd >= 0)
close_nointr_nofail(s->epoll_fd);
if (s->bus) {
dbus_connection_flush(s->bus);
dbus_connection_close(s->bus);
dbus_connection_unref(s->bus);
}
}
static int server_init(Server *s, unsigned n_sockets) {
int r;
unsigned i;
DBusError error;
assert(s);
assert(n_sockets > 0);
dbus_error_init(&error);
zero(*s);
if ((s->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0) {
r = -errno;
log_error("Failed to create epoll object: %s", strerror(errno));
goto fail;
}
for (i = 0; i < n_sockets; i++) {
struct epoll_event ev;
Fifo *f;
int fd;
fd = SD_LISTEN_FDS_START+i;
if ((r = sd_is_fifo(fd, NULL)) < 0) {
log_error("Failed to determine file descriptor type: %s", strerror(-r));
goto fail;
}
if (!r) {
log_error("Wrong file descriptor type.");
r = -EINVAL;
goto fail;
}
if (!(f = new0(Fifo, 1))) {
r = -ENOMEM;
log_error("Failed to create fifo object: %s", strerror(errno));
goto fail;
}
f->fd = -1;
zero(ev);
ev.events = EPOLLIN;
ev.data.ptr = f;
if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
r = -errno;
fifo_free(f);
log_error("Failed to add fifo fd to epoll object: %s", strerror(errno));
goto fail;
}
f->fd = fd;
LIST_PREPEND(Fifo, fifo, s->fifos, f);
f->server = s;
s->n_fifos ++;
}
if (bus_connect(DBUS_BUS_SYSTEM, &s->bus, NULL, &error) < 0) {
log_error("Failed to get D-Bus connection: %s", bus_error_message(&error));
goto fail;
}
return 0;
fail:
server_done(s);
dbus_error_free(&error);
return r;
}
static int process_event(Server *s, struct epoll_event *ev) {
int r;
Fifo *f;
assert(s);
if (!(ev->events & EPOLLIN)) {
log_info("Got invalid event from epoll. (3)");
return -EIO;
}
f = (Fifo*) ev->data.ptr;
if ((r = fifo_process(f)) < 0) {
log_info("Got error on fifo: %s", strerror(-r));
fifo_free(f);
return r;
}
return 0;
}
int main(int argc, char *argv[]) {
Server server;
int r = EXIT_FAILURE, n;
if (getppid() != 1) {
log_error("This program should be invoked by init only.");
return EXIT_FAILURE;
}
if (argc > 1) {
log_error("This program does not take arguments.");
return EXIT_FAILURE;
}
log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
log_parse_environment();
log_open();
umask(0022);
if ((n = sd_listen_fds(true)) < 0) {
log_error("Failed to read listening file descriptors from environment: %s", strerror(-r));
return EXIT_FAILURE;
}
if (n <= 0 || n > SERVER_FD_MAX) {
log_error("No or too many file descriptors passed.");
return EXIT_FAILURE;
}
if (server_init(&server, (unsigned) n) < 0)
return EXIT_FAILURE;
log_debug("systemd-initctl running as pid %lu", (unsigned long) getpid());
sd_notify(false,
"READY=1\n"
"STATUS=Processing requests...");
while (!server.quit) {
struct epoll_event event;
int k;
if ((k = epoll_wait(server.epoll_fd,
&event, 1,
TIMEOUT_MSEC)) < 0) {
if (errno == EINTR)
continue;
log_error("epoll_wait() failed: %s", strerror(errno));
goto fail;
}
if (k <= 0)
break;
if (process_event(&server, &event) < 0)
goto fail;
}
r = EXIT_SUCCESS;
log_debug("systemd-initctl stopped as pid %lu", (unsigned long) getpid());
fail:
sd_notify(false,
"STATUS=Shutting down...");
server_done(&server);
dbus_shutdown();
return r;
}
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