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systemd/main.c

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/*-*- Mode: C; c-basic-offset: 8 -*-*/
/***
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 <dbus/dbus.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <getopt.h>
#include <signal.h>
#include <sys/wait.h>
#include <fcntl.h>
#include "manager.h"
#include "log.h"
#include "mount-setup.h"
#include "hostname-setup.h"
#include "loopback-setup.h"
#include "load-fragment.h"
#include "fdset.h"
static enum {
ACTION_RUN,
ACTION_HELP,
ACTION_TEST,
ACTION_DUMP_CONFIGURATION_ITEMS
} action = ACTION_RUN;
static char *default_unit = NULL;
static ManagerRunningAs running_as = _MANAGER_RUNNING_AS_INVALID;
static bool dump_core = true;
static bool crash_shell = false;
static int crash_chvt = -1;
static bool confirm_spawn = false;
static FILE* serialization = NULL;
_noreturn static void freeze(void) {
for (;;)
pause();
}
static void nop_handler(int sig) {
}
_noreturn static void crash(int sig) {
if (!dump_core)
log_error("Caught <%s>, not dumping core.", strsignal(sig));
else {
struct sigaction sa;
pid_t pid;
/* We want to wait for the core process, hence let's enable SIGCHLD */
zero(sa);
sa.sa_handler = nop_handler;
sa.sa_flags = SA_NOCLDSTOP|SA_RESTART;
assert_se(sigaction(SIGCHLD, &sa, NULL) == 0);
if ((pid = fork()) < 0)
log_error("Caught <%s>, cannot fork for core dump: %s", strsignal(sig), strerror(errno));
else if (pid == 0) {
struct rlimit rl;
/* Enable default signal handler for core dump */
zero(sa);
sa.sa_handler = SIG_DFL;
assert_se(sigaction(sig, &sa, NULL) == 0);
/* Don't limit the core dump size */
zero(rl);
rl.rlim_cur = RLIM_INFINITY;
rl.rlim_max = RLIM_INFINITY;
setrlimit(RLIMIT_CORE, &rl);
/* Just to be sure... */
assert_se(chdir("/") == 0);
/* Raise the signal again */
raise(sig);
assert_not_reached("We shouldn't be here...");
_exit(1);
} else {
int status, r;
/* Order things nicely. */
if ((r = waitpid(pid, &status, 0)) < 0)
log_error("Caught <%s>, waitpid() failed: %s", strsignal(sig), strerror(errno));
else if (!WCOREDUMP(status))
log_error("Caught <%s>, core dump failed.", strsignal(sig));
else
log_error("Caught <%s>, dumped core as pid %llu.", strsignal(sig), (unsigned long long) pid);
}
}
if (crash_chvt)
chvt(crash_chvt);
if (crash_shell) {
struct sigaction sa;
pid_t pid;
log_info("Executing crash shell in 10s...");
sleep(10);
/* Let the kernel reap children for us */
zero(sa);
sa.sa_handler = SIG_IGN;
sa.sa_flags = SA_NOCLDSTOP|SA_NOCLDWAIT|SA_RESTART;
assert_se(sigaction(SIGCHLD, &sa, NULL) == 0);
if ((pid = fork()) < 0)
log_error("Failed to fork off crash shell: %s", strerror(errno));
else if (pid == 0) {
execl("/bin/sh", "/bin/sh", NULL);
log_error("execl() failed: %s", strerror(errno));
_exit(1);
}
log_info("Successfully spawned crash shall as pid %llu.", (unsigned long long) pid);
}
log_info("Freezing execution.");
freeze();
}
static void install_crash_handler(void) {
struct sigaction sa;
zero(sa);
sa.sa_handler = crash;
sa.sa_flags = SA_NODEFER;
assert_se(sigaction(SIGSEGV, &sa, NULL) == 0);
assert_se(sigaction(SIGILL, &sa, NULL) == 0);
assert_se(sigaction(SIGFPE, &sa, NULL) == 0);
assert_se(sigaction(SIGBUS, &sa, NULL) == 0);
assert_se(sigaction(SIGQUIT, &sa, NULL) == 0);
assert_se(sigaction(SIGABRT, &sa, NULL) == 0);
}
static int console_setup(bool do_reset) {
int tty_fd = -1, null_fd = -1, r = 0;
/* If we are init, we connect stdout/stderr to /dev/console
* and stdin to /dev/null and make sure we don't have a
* controlling tty. */
release_terminal();
if ((tty_fd = open_terminal("/dev/console", O_WRONLY)) < 0) {
log_error("Failed to open /dev/console: %s", strerror(-tty_fd));
r = -tty_fd;
goto finish;
}
if ((null_fd = open("/dev/null", O_RDONLY)) < 0) {
log_error("Failed to open /dev/null: %m");
r = -errno;
goto finish;
}
assert(tty_fd >= 3);
assert(null_fd >= 3);
if (do_reset)
if (reset_terminal(tty_fd) < 0)
log_error("Failed to reset /dev/console: %m");
if (dup2(tty_fd, STDOUT_FILENO) < 0 ||
dup2(tty_fd, STDERR_FILENO) < 0 ||
dup2(null_fd, STDIN_FILENO) < 0) {
log_error("Failed to dup2() device: %m");
r = -errno;
goto finish;
}
r = 0;
finish:
if (tty_fd >= 0)
close_nointr_nofail(tty_fd);
if (null_fd >= 0)
close_nointr_nofail(null_fd);
return r;
}
static int set_default_unit(const char *u) {
char *c;
assert(u);
if (!(c = strdup(u)))
return -ENOMEM;
free(default_unit);
default_unit = c;
return 0;
}
static int parse_proc_cmdline_word(const char *word) {
static const char * const rlmap[] = {
"single", SPECIAL_RUNLEVEL1_TARGET,
"-s", SPECIAL_RUNLEVEL1_TARGET,
"s", SPECIAL_RUNLEVEL1_TARGET,
"S", SPECIAL_RUNLEVEL1_TARGET,
"1", SPECIAL_RUNLEVEL1_TARGET,
"2", SPECIAL_RUNLEVEL2_TARGET,
"3", SPECIAL_RUNLEVEL3_TARGET,
"4", SPECIAL_RUNLEVEL4_TARGET,
"5", SPECIAL_RUNLEVEL5_TARGET
};
if (startswith(word, "systemd.default="))
return set_default_unit(word + 16);
else if (startswith(word, "systemd.log_target=")) {
if (log_set_target_from_string(word + 19) < 0)
log_warning("Failed to parse log target %s. Ignoring.", word + 19);
} else if (startswith(word, "systemd.log_level=")) {
if (log_set_max_level_from_string(word + 18) < 0)
log_warning("Failed to parse log level %s. Ignoring.", word + 18);
} else if (startswith(word, "systemd.dump_core=")) {
int r;
if ((r = parse_boolean(word + 18)) < 0)
log_warning("Failed to parse dump core switch %s, Ignoring.", word + 18);
else
dump_core = r;
} else if (startswith(word, "systemd.crash_shell=")) {
int r;
if ((r = parse_boolean(word + 20)) < 0)
log_warning("Failed to parse crash shell switch %s, Ignoring.", word + 20);
else
crash_shell = r;
} else if (startswith(word, "systemd.confirm_spawn=")) {
int r;
if ((r = parse_boolean(word + 22)) < 0)
log_warning("Failed to parse confirm spawn switch %s, Ignoring.", word + 22);
else
confirm_spawn = r;
} else if (startswith(word, "systemd.crash_chvt=")) {
int k;
if (safe_atoi(word + 19, &k) < 0)
log_warning("Failed to parse crash chvt switch %s, Ignoring.", word + 19);
else
crash_chvt = k;
} else if (startswith(word, "systemd.")) {
log_warning("Unknown kernel switch %s. Ignoring.", word);
log_info("Supported kernel switches:");
log_info("systemd.default=UNIT Default unit to start");
log_info("systemd.log_target=console|kmsg|syslog Log target");
log_info("systemd.log_level=LEVEL Log level");
log_info("systemd.dump_core=0|1 Dump core on crash");
log_info("systemd.crash_shell=0|1 On crash run shell");
log_info("systemd.crash_chvt=N Change to VT #N on crash");
log_info("systemd.confirm_spawn=0|1 Confirm every process spawn");
} else {
unsigned i;
/* SysV compatibility */
for (i = 0; i < ELEMENTSOF(rlmap); i += 2)
if (streq(word, rlmap[i]))
return set_default_unit(rlmap[i+1]);
}
return 0;
}
static int parse_proc_cmdline(void) {
char *line;
int r;
char *w;
size_t l;
char *state;
if ((r = read_one_line_file("/proc/cmdline", &line)) < 0) {
log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(errno));
return 0;
}
FOREACH_WORD_QUOTED(w, l, line, state) {
char *word;
if (!(word = strndup(w, l))) {
r = -ENOMEM;
goto finish;
}
r = parse_proc_cmdline_word(word);
free(word);
if (r < 0)
goto finish;
}
r = 0;
finish:
free(line);
return r;
}
static int parse_argv(int argc, char *argv[]) {
enum {
ARG_LOG_LEVEL = 0x100,
ARG_LOG_TARGET,
ARG_DEFAULT,
ARG_RUNNING_AS,
ARG_TEST,
ARG_DUMP_CONFIGURATION_ITEMS,
ARG_CONFIRM_SPAWN,
ARG_DESERIALIZE
};
static const struct option options[] = {
{ "log-level", required_argument, NULL, ARG_LOG_LEVEL },
{ "log-target", required_argument, NULL, ARG_LOG_TARGET },
{ "default", required_argument, NULL, ARG_DEFAULT },
{ "running-as", required_argument, NULL, ARG_RUNNING_AS },
{ "test", no_argument, NULL, ARG_TEST },
{ "help", no_argument, NULL, 'h' },
{ "dump-configuration-items", no_argument, NULL, ARG_DUMP_CONFIGURATION_ITEMS },
{ "confirm-spawn", no_argument, NULL, ARG_CONFIRM_SPAWN },
{ "deserialize", required_argument, NULL, ARG_DESERIALIZE },
{ NULL, 0, NULL, 0 }
};
int c, r;
assert(argc >= 1);
assert(argv);
while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
switch (c) {
case ARG_LOG_LEVEL:
if ((r = log_set_max_level_from_string(optarg)) < 0) {
log_error("Failed to parse log level %s.", optarg);
return r;
}
break;
case ARG_LOG_TARGET:
if ((r = log_set_target_from_string(optarg)) < 0) {
log_error("Failed to parse log target %s.", optarg);
return r;
}
break;
case ARG_DEFAULT:
if ((r = set_default_unit(optarg)) < 0) {
log_error("Failed to set default unit %s: %s", optarg, strerror(-r));
return r;
}
break;
case ARG_RUNNING_AS: {
ManagerRunningAs as;
if ((as = manager_running_as_from_string(optarg)) < 0) {
log_error("Failed to parse running as value %s", optarg);
return -EINVAL;
}
running_as = as;
break;
}
case ARG_TEST:
action = ACTION_TEST;
break;
case ARG_DUMP_CONFIGURATION_ITEMS:
action = ACTION_DUMP_CONFIGURATION_ITEMS;
break;
case ARG_CONFIRM_SPAWN:
confirm_spawn = true;
break;
case ARG_DESERIALIZE: {
int fd;
FILE *f;
if ((r = safe_atoi(optarg, &fd)) < 0 || fd < 0) {
log_error("Failed to parse deserialize option %s.", optarg);
return r;
}
if (!(f = fdopen(fd, "r"))) {
log_error("Failed to open serialization fd: %m");
return r;
}
if (serialization)
fclose(serialization);
serialization = f;
break;
}
case 'h':
action = ACTION_HELP;
break;
case '?':
return -EINVAL;
default:
log_error("Unknown option code %c", c);
return -EINVAL;
}
/* PID 1 will get the kernel arguments as parameters, which we
* ignore and unconditionally read from
* /proc/cmdline. However, we need to ignore those arguments
* here. */
if (running_as != MANAGER_INIT && optind < argc) {
log_error("Excess arguments.");
return -EINVAL;
}
return 0;
}
static int help(void) {
printf("%s [options]\n\n"
" -h --help Show this help\n"
" --default=UNIT Set default unit\n"
" --log-level=LEVEL Set log level\n"
" --log-target=TARGET Set log target (console, syslog, kmsg)\n"
" --running-as=AS Set running as (init, system, session)\n"
" --test Determine startup sequence, dump it and exit\n"
" --dump-configuration-items Dump understood unit configuration items\n"
" --confirm-spawn Ask for confirmation when spawning processes\n",
__progname);
return 0;
}
static int prepare_reexecute(Manager *m, FILE **_f, FDSet **_fds) {
FILE *f = NULL;
FDSet *fds = NULL;
int r;
assert(m);
assert(_f);
assert(_fds);
if ((r = manager_open_serialization(&f)) < 0) {
log_error("Failed to create serialization faile: %s", strerror(-r));
goto fail;
}
if (!(fds = fdset_new())) {
r = -ENOMEM;
log_error("Failed to allocate fd set: %s", strerror(-r));
goto fail;
}
if ((r = manager_serialize(m, f, fds)) < 0) {
log_error("Failed to serialize state: %s", strerror(-r));
goto fail;
}
if (fseeko(f, 0, SEEK_SET) < 0) {
log_error("Failed to rewind serialization fd: %m");
goto fail;
}
if ((r = fd_cloexec(fileno(f), false)) < 0) {
log_error("Failed to disable O_CLOEXEC for serialization: %s", strerror(-r));
goto fail;
}
if ((r = fdset_cloexec(fds, false)) < 0) {
log_error("Failed to disable O_CLOEXEC for serialization fds: %s", strerror(-r));
goto fail;
}
*_f = f;
*_fds = fds;
return 0;
fail:
fdset_free(fds);
if (f)
fclose(f);
return r;
}
int main(int argc, char *argv[]) {
Manager *m = NULL;
Unit *target = NULL;
Job *job = NULL;
int r, retval = 1;
FDSet *fds = NULL;
bool reexecute = false;
if (getpid() == 1)
running_as = MANAGER_INIT;
else if (getuid() == 0)
running_as = MANAGER_SYSTEM;
else
running_as = MANAGER_SESSION;
if (set_default_unit(SPECIAL_DEFAULT_TARGET) < 0)
goto finish;
/* Mount /proc, /sys and friends, so that /proc/cmdline and
* /proc/$PID/fd is available. */
if (mount_setup() < 0)
goto finish;
/* Reset all signal handlers. */
assert_se(reset_all_signal_handlers() == 0);
/* If we are init, we can block sigkill. Yay. */
ignore_signal(SIGKILL);
ignore_signal(SIGPIPE);
if (running_as != MANAGER_SESSION)
if (parse_proc_cmdline() < 0)
goto finish;
log_parse_environment();
if (parse_argv(argc, argv) < 0)
goto finish;
if (action == ACTION_HELP) {
retval = help();
goto finish;
} else if (action == ACTION_DUMP_CONFIGURATION_ITEMS) {
unit_dump_config_items(stdout);
retval = 0;
goto finish;
}
assert_se(action == ACTION_RUN || action == ACTION_TEST);
/* Remember open file descriptors for later deserialization */
if (serialization) {
if ((r = fdset_new_fill(&fds)) < 0) {
log_error("Failed to allocate fd set: %s", strerror(-r));
goto finish;
}
assert_se(fdset_remove(fds, fileno(serialization)) >= 0);
} else
close_all_fds(NULL, 0);
/* Set up PATH unless it is already set */
setenv("PATH",
"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
running_as == MANAGER_INIT);
/* Move out of the way, so that we won't block unmounts */
assert_se(chdir("/") == 0);
if (running_as != MANAGER_SESSION) {
/* Become a session leader if we aren't one yet. */
setsid();
/* Disable the umask logic */
umask(0);
}
/* Reset the console, but only if this is really init and we
* are freshly booted */
if (running_as == MANAGER_INIT && action == ACTION_RUN)
console_setup(getpid() == 1 && !serialization);
/* Make sure D-Bus doesn't fiddle with the SIGPIPE handlers */
dbus_connection_set_change_sigpipe(FALSE);
/* Open the logging devices, if possible and necessary */
log_open_syslog();
log_open_kmsg();
/* Make sure we leave a core dump without panicing the
* kernel. */
if (getpid() == 1)
install_crash_handler();
log_debug("systemd running in %s mode.", manager_running_as_to_string(running_as));
if (running_as == MANAGER_INIT) {
hostname_setup();
loopback_setup();
}
if ((r = manager_new(running_as, confirm_spawn, &m)) < 0) {
log_error("Failed to allocate manager object: %s", strerror(-r));
goto finish;
}
if ((r = manager_startup(m, serialization, fds)) < 0)
log_error("Failed to fully start up daemon: %s", strerror(-r));
if (fds) {
/* This will close all file descriptors that were opened, but
* not claimed by any unit. */
fdset_free(fds);
fds = NULL;
}
if (serialization) {
fclose(serialization);
serialization = NULL;
} else {
log_debug("Activating default unit: %s", default_unit);
if ((r = manager_load_unit(m, default_unit, NULL, &target)) < 0) {
log_error("Failed to load default target: %s", strerror(-r));
log_info("Trying to load rescue target...");
if ((r = manager_load_unit(m, SPECIAL_RESCUE_TARGET, NULL, &target)) < 0) {
log_error("Failed to load rescue target: %s", strerror(-r));
goto finish;
}
}
if (action == ACTION_TEST) {
printf("-> By units:\n");
manager_dump_units(m, stdout, "\t");
}
if ((r = manager_add_job(m, JOB_START, target, JOB_REPLACE, false, &job)) < 0) {
log_error("Failed to start default target: %s", strerror(-r));
goto finish;
}
if (action == ACTION_TEST) {
printf("-> By jobs:\n");
manager_dump_jobs(m, stdout, "\t");
retval = 0;
goto finish;
}
}
for (;;) {
if ((r = manager_loop(m)) < 0) {
log_error("Failed to run mainloop: %s", strerror(-r));
goto finish;
}
switch (m->exit_code) {
case MANAGER_EXIT:
retval = 0;
log_debug("Exit.");
goto finish;
case MANAGER_RELOAD:
if ((r = manager_reload(m)) < 0)
log_error("Failed to reload: %s", strerror(-r));
break;
case MANAGER_REEXECUTE:
if (prepare_reexecute(m, &serialization, &fds) < 0)
goto finish;
reexecute = true;
log_debug("Reexecuting.");
goto finish;
default:
assert_not_reached("Unknown exit code.");
}
}
finish:
if (m)
manager_free(m);
free(default_unit);
dbus_shutdown();
if (reexecute) {
const char *args[11];
unsigned i = 0;
char sfd[16];
assert(serialization);
assert(fds);
args[i++] = SYSTEMD_BINARY_PATH;
args[i++] = "--log-level";
args[i++] = log_level_to_string(log_get_max_level());
args[i++] = "--log-target";
args[i++] = log_target_to_string(log_get_target());
args[i++] = "--running-as";
args[i++] = manager_running_as_to_string(running_as);
snprintf(sfd, sizeof(sfd), "%i", fileno(serialization));
char_array_0(sfd);
args[i++] = "--deserialize";
args[i++] = sfd;
if (confirm_spawn)
args[i++] = "--confirm-spawn";
args[i++] = NULL;
assert(i <= ELEMENTSOF(args));
execv(args[0], (char* const*) args);
log_error("Failed to reexecute: %m");
}
if (serialization)
fclose(serialization);
if (fds)
fdset_free(fds);
if (getpid() == 1)
freeze();
return retval;
}
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