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busybox/debianutils/start_stop_daemon.c
Denis Vlasenko 75897ea6d5 start_stop_daemon: accept (and ignore) -R <param>
2008-09-27 01:05:13 +00:00

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/* vi: set sw=4 ts=4: */
/*
* Mini start-stop-daemon implementation(s) for busybox
*
* Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
* Adapted for busybox David Kimdon <dwhedon@gordian.com>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
/*
This is how it is supposed to work:
start-stop-daemon [OPTIONS] [--start|--stop] [[--] arguments...]
One (only) of these must be given:
-S,--start Start
-K,--stop Stop
Search for matching processes.
If --stop is given, stop all matching processes (by sending a signal).
If --start is given, start a new process unless a matching process was found.
Options controlling process matching
(if multiple conditions are specified, all must match):
-u,--user USERNAME|UID Only consider this user's processes
-n,--name PROCESS_NAME Look for processes by matching PROCESS_NAME
with comm field in /proc/$PID/stat.
Only basename is compared:
"ntpd" == "./ntpd" == "/path/to/ntpd".
[TODO: can PROCESS_NAME be a full pathname? Should we require full match then
with /proc/$PID/exe or argv[0] (comm can't be matched, it never contains path)]
-x,--exec EXECUTABLE Look for processes that were started with this
command in /proc/$PID/cmdline.
Unlike -n, we match against the full path:
"ntpd" != "./ntpd" != "/path/to/ntpd"
-p,--pidfile PID_FILE Look for processes with PID from this file
Options which are valid for --start only:
-x,--exec EXECUTABLE Program to run (1st arg of execvp). Mandatory.
-a,--startas NAME argv[0] (defaults to EXECUTABLE)
-b,--background Put process into background
-N,--nicelevel N Add N to process' nice level
-c,--chuid USER[:[GRP]] Change to specified user [and group]
-m,--make-pidfile Write PID to the pidfile
(both -m and -p must be given!)
Options which are valid for --stop only:
-s,--signal SIG Signal to send (default:TERM)
-t,--test Exit with status 0 if process is found
(we don't actually start or stop daemons)
Misc options:
-o,--oknodo Exit with status 0 if nothing is done
-q,--quiet Quiet
-v,--verbose Verbose
*/
#include <sys/resource.h>
/* Override ENABLE_FEATURE_PIDFILE */
#define WANT_PIDFILE 1
#include "libbb.h"
struct pid_list {
struct pid_list *next;
pid_t pid;
};
enum {
CTX_STOP = (1 << 0),
CTX_START = (1 << 1),
OPT_BACKGROUND = (1 << 2), // -b
OPT_QUIET = (1 << 3), // -q
OPT_TEST = (1 << 4), // -t
OPT_MAKEPID = (1 << 5), // -m
OPT_a = (1 << 6), // -a
OPT_n = (1 << 7), // -n
OPT_s = (1 << 8), // -s
OPT_u = (1 << 9), // -u
OPT_c = (1 << 10), // -c
OPT_x = (1 << 11), // -x
OPT_p = (1 << 12), // -p
OPT_OKNODO = (1 << 13) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
OPT_VERBOSE = (1 << 14) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
OPT_NICELEVEL = (1 << 15) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
};
#define QUIET (option_mask32 & OPT_QUIET)
#define TEST (option_mask32 & OPT_TEST)
struct globals {
struct pid_list *found;
char *userspec;
char *cmdname;
char *execname;
char *pidfile;
int user_id;
smallint signal_nr;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
#define found (G.found )
#define userspec (G.userspec )
#define cmdname (G.cmdname )
#define execname (G.execname )
#define pidfile (G.pidfile )
#define user_id (G.user_id )
#define signal_nr (G.signal_nr )
#define INIT_G() do { \
user_id = -1; \
signal_nr = 15; \
} while (0)
#ifdef OLDER_VERSION_OF_X
/* -x,--exec EXECUTABLE
* Look for processes with matching /proc/$PID/exe.
* Match is performed using device+inode.
*/
static int pid_is_exec(pid_t pid)
{
struct stat st;
char buf[sizeof("/proc//exe") + sizeof(int)*3];
sprintf(buf, "/proc/%u/exe", (unsigned)pid);
if (stat(buf, &st) < 0)
return 0;
if (st.st_dev == execstat.st_dev
&& st.st_ino == execstat.st_ino)
return 1;
return 0;
}
#endif
static int pid_is_exec(pid_t pid)
{
ssize_t bytes;
char buf[PATH_MAX];
sprintf(buf, "/proc/%u/cmdline", (unsigned)pid);
bytes = open_read_close(buf, buf, sizeof(buf) - 1);
if (bytes > 0) {
buf[bytes] = '\0';
return strcmp(buf, execname) == 0;
}
return 0;
}
static int pid_is_name(pid_t pid)
{
/* /proc/PID/stat is "PID (comm_15_bytes_max) ..." */
char buf[32]; /* should be enough */
char *p, *pe;
sprintf(buf, "/proc/%u/stat", (unsigned)pid);
if (open_read_close(buf, buf, sizeof(buf) - 1) < 0)
return 0;
buf[sizeof(buf) - 1] = '\0'; /* paranoia */
p = strchr(buf, '(');
if (!p)
return 0;
pe = strrchr(++p, ')');
if (!pe)
return 0;
*pe = '\0';
/* we require comm to match and to not be truncated */
/* in Linux, if comm is 15 chars, it may be a truncated
* name, so we don't allow that to match */
if (strlen(p) >= COMM_LEN - 1) /* COMM_LEN is 16 */
return 0;
return strcmp(p, cmdname) == 0;
}
static int pid_is_user(int pid)
{
struct stat sb;
char buf[sizeof("/proc/") + sizeof(int)*3];
sprintf(buf, "/proc/%u", (unsigned)pid);
if (stat(buf, &sb) != 0)
return 0;
return (sb.st_uid == (uid_t)user_id);
}
static void check(int pid)
{
struct pid_list *p;
if (execname && !pid_is_exec(pid)) {
return;
}
if (cmdname && !pid_is_name(pid)) {
return;
}
if (userspec && !pid_is_user(pid)) {
return;
}
p = xmalloc(sizeof(*p));
p->next = found;
p->pid = pid;
found = p;
}
static void do_pidfile(void)
{
FILE *f;
unsigned pid;
f = fopen_for_read(pidfile);
if (f) {
if (fscanf(f, "%u", &pid) == 1)
check(pid);
fclose(f);
} else if (errno != ENOENT)
bb_perror_msg_and_die("open pidfile %s", pidfile);
}
static void do_procinit(void)
{
DIR *procdir;
struct dirent *entry;
int pid;
if (pidfile) {
do_pidfile();
return;
}
procdir = xopendir("/proc");
pid = 0;
while (1) {
errno = 0; /* clear any previous error */
entry = readdir(procdir);
// TODO: this check is too generic, it's better
// to check for exact errno(s) which mean that we got stale entry
if (errno) /* Stale entry, process has died after opendir */
continue;
if (!entry) /* EOF, no more entries */
break;
pid = bb_strtou(entry->d_name, NULL, 10);
if (errno) /* NaN */
continue;
check(pid);
}
closedir(procdir);
if (!pid)
bb_error_msg_and_die("nothing in /proc - not mounted?");
}
static int do_stop(void)
{
char *what;
struct pid_list *p;
int killed = 0;
if (cmdname) {
if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(cmdname);
if (!ENABLE_FEATURE_CLEAN_UP) what = cmdname;
} else if (execname) {
if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(execname);
if (!ENABLE_FEATURE_CLEAN_UP) what = execname;
} else if (pidfile) {
what = xasprintf("process in pidfile '%s'", pidfile);
} else if (userspec) {
what = xasprintf("process(es) owned by '%s'", userspec);
} else {
bb_error_msg_and_die("internal error, please report");
}
if (!found) {
if (!QUIET)
printf("no %s found; none killed\n", what);
killed = -1;
goto ret;
}
for (p = found; p; p = p->next) {
if (TEST || kill(p->pid, signal_nr) == 0) {
killed++;
} else {
p->pid = 0;
bb_perror_msg("warning: killing process %u", (unsigned)p->pid);
}
}
if (!QUIET && killed) {
printf("stopped %s (pid", what);
for (p = found; p; p = p->next)
if (p->pid)
printf(" %u", (unsigned)p->pid);
puts(")");
}
ret:
if (ENABLE_FEATURE_CLEAN_UP)
free(what);
return killed;
}
#if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
static const char start_stop_daemon_longopts[] ALIGN1 =
"stop\0" No_argument "K"
"start\0" No_argument "S"
"background\0" No_argument "b"
"quiet\0" No_argument "q"
"test\0" No_argument "t"
"make-pidfile\0" No_argument "m"
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
"oknodo\0" No_argument "o"
"verbose\0" No_argument "v"
"nicelevel\0" Required_argument "N"
#endif
"startas\0" Required_argument "a"
"name\0" Required_argument "n"
"signal\0" Required_argument "s"
"user\0" Required_argument "u"
"chuid\0" Required_argument "c"
"exec\0" Required_argument "x"
"pidfile\0" Required_argument "p"
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
"retry\0" Required_argument "R"
#endif
;
#endif
int start_stop_daemon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int start_stop_daemon_main(int argc UNUSED_PARAM, char **argv)
{
unsigned opt;
char *signame;
char *startas;
char *chuid;
#ifdef OLDER_VERSION_OF_X
struct stat execstat;
#endif
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
// char *retry_arg = NULL;
// int retries = -1;
char *opt_N;
#endif
INIT_G();
#if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
applet_long_options = start_stop_daemon_longopts;
#endif
/* -K or -S is required; they are mutually exclusive */
/* -p is required if -m is given */
/* -xpun (at least one) is required if -K is given */
/* -xa (at least one) is required if -S is given */
/* -q turns off -v */
opt_complementary = "K:S:K--S:S--K:m?p:K?xpun:S?xa"
USE_FEATURE_START_STOP_DAEMON_FANCY("q-v");
opt = getopt32(argv, "KSbqtma:n:s:u:c:x:p:"
USE_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:"),
&startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
USE_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N)
/* We accept and ignore -R <param> / --retry <param> */
USE_FEATURE_START_STOP_DAEMON_FANCY(,NULL)
);
if (opt & OPT_s) {
signal_nr = get_signum(signame);
if (signal_nr < 0) bb_show_usage();
}
if (!(opt & OPT_a))
startas = execname;
if (!execname) /* in case -a is given and -x is not */
execname = startas;
// USE_FEATURE_START_STOP_DAEMON_FANCY(
// if (retry_arg)
// retries = xatoi_u(retry_arg);
// )
//argc -= optind;
argv += optind;
if (userspec) {
user_id = bb_strtou(userspec, NULL, 10);
if (errno)
user_id = xuname2uid(userspec);
}
/* Both start and stop need to know current processes */
do_procinit();
if (opt & CTX_STOP) {
int i = do_stop();
return (opt & OPT_OKNODO) ? 0 : (i <= 0);
}
if (found) {
if (!QUIET)
printf("%s is already running\n%u\n", execname, (unsigned)found->pid);
return !(opt & OPT_OKNODO);
}
#ifdef OLDER_VERSION_OF_X
if (execname)
xstat(execname, &execstat);
#endif
*--argv = startas;
if (opt & OPT_BACKGROUND) {
#if BB_MMU
bb_daemonize(DAEMON_DEVNULL_STDIO + DAEMON_CLOSE_EXTRA_FDS);
/* DAEMON_DEVNULL_STDIO is superfluous -
* it's always done by bb_daemonize() */
#else
pid_t pid = vfork();
if (pid < 0) /* error */
bb_perror_msg_and_die("vfork");
if (pid != 0) {
/* parent */
/* why _exit? the child may have changed the stack,
* so "return 0" may do bad things */
_exit(EXIT_SUCCESS);
}
/* Child */
setsid(); /* detach from controlling tty */
/* Redirect stdio to /dev/null, close extra FDs.
* We do not actually daemonize because of DAEMON_ONLY_SANITIZE */
bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO
+ DAEMON_CLOSE_EXTRA_FDS
+ DAEMON_ONLY_SANITIZE,
NULL /* argv, unused */ );
#endif
}
if (opt & OPT_MAKEPID) {
/* User wants _us_ to make the pidfile */
write_pidfile(pidfile);
}
if (opt & OPT_c) {
struct bb_uidgid_t ugid = { -1, -1 };
parse_chown_usergroup_or_die(&ugid, chuid);
if (ugid.gid != (gid_t) -1) xsetgid(ugid.gid);
if (ugid.uid != (uid_t) -1) xsetuid(ugid.uid);
}
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
if (opt & OPT_NICELEVEL) {
/* Set process priority */
int prio = getpriority(PRIO_PROCESS, 0) + xatoi_range(opt_N, INT_MIN/2, INT_MAX/2);
if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
bb_perror_msg_and_die("setpriority(%d)", prio);
}
}
#endif
execvp(startas, argv);
bb_perror_msg_and_die("cannot start %s", startas);
}
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