busybox/debianutils/start_stop_daemon.c

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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.
*/
/* NB: we have a problem here with /proc/NN/exe usage, similar to
* one fixed in killall/pidof */
#include <getopt.h>
#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;
};
struct globals {
struct pid_list *found;
char *userspec;
char *cmdname;
char *execname;
char *pidfile;
int user_id;
smallint quiet;
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 quiet (G.quiet )
#define signal_nr (G.signal_nr )
#define INIT_G() \
do { \
user_id = -1; \
signal_nr = 15; \
} while (0)
static int pid_is_exec(pid_t pid, const char *name)
{
char buf[sizeof("/proc//exe") + sizeof(int)*3];
char *execbuf;
int n;
sprintf(buf, "/proc/%u/exe", pid);
n = strlen(name) + 1;
execbuf = xzalloc(n + 1);
readlink(buf, execbuf, n);
/* if readlink fails because link target is longer than strlen(name),
* execbuf still contains "", and strcmp will return !0. */
n = strcmp(execbuf, name);
if (ENABLE_FEATURE_CLEAN_UP)
free(execbuf);
return !n; /* nonzero (true) if execbuf == name */
}
static int pid_is_user(int pid, int uid)
{
struct stat sb;
char buf[sizeof("/proc/") + sizeof(int)*3];
sprintf(buf, "/proc/%u", pid);
if (stat(buf, &sb) != 0)
return 0;
return (sb.st_uid == uid);
}
static int pid_is_cmd(pid_t pid, const char *name)
{
char fname[sizeof("/proc//stat") + sizeof(int)*3];
char *buf;
int r = 0;
sprintf(fname, "/proc/%u/stat", pid);
buf = xmalloc_open_read_close(fname, NULL);
if (buf) {
char *p = strchr(buf, '(');
if (p) {
char *pe = strrchr(++p, ')');
if (pe) {
*pe = '\0';
r = !strcmp(p, name);
}
}
free(buf);
}
return r;
}
static void check(int pid)
{
struct pid_list *p;
if (execname && !pid_is_exec(pid, execname)) {
return;
}
if (userspec && !pid_is_user(pid, user_id)) {
return;
}
if (cmdname && !pid_is_cmd(pid, cmdname)) {
return;
}
p = xmalloc(sizeof(*p));
p->next = found;
p->pid = pid;
found = p;
}
static void do_pidfile(void)
{
FILE *f;
unsigned pid;
f = fopen(pidfile, "r");
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 ((entry = readdir(procdir)) != NULL) {
pid = bb_strtou(entry->d_name, NULL, 10);
if (errno)
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;
do_procinit();
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 (kill(p->pid, signal_nr) == 0) {
p->pid = - p->pid;
killed++;
} else {
bb_perror_msg("warning: killing process %u", p->pid);
}
}
if (!quiet && killed) {
printf("stopped %s (pid", what);
for (p = found; p; p = p->next)
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if (p->pid < 0)
printf(" %u", - 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 =
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"stop\0" No_argument "K"
"start\0" No_argument "S"
"background\0" No_argument "b"
"quiet\0" No_argument "q"
"make-pidfile\0" No_argument "m"
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
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"oknodo\0" No_argument "o"
"verbose\0" No_argument "v"
"nicelevel\0" Required_argument "N"
#endif
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"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
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"retry\0" Required_argument "R"
#endif
;
#endif
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enum {
CTX_STOP = 0x1,
CTX_START = 0x2,
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OPT_BACKGROUND = 0x4, // -b
OPT_QUIET = 0x8, // -q
OPT_MAKEPID = 0x10, // -m
OPT_a = 0x20, // -a
OPT_n = 0x40, // -n
OPT_s = 0x80, // -s
OPT_u = 0x100, // -u
OPT_c = 0x200, // -c
OPT_x = 0x400, // -x
OPT_p = 0x800, // -p
OPT_OKNODO = 0x1000 * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
OPT_VERBOSE = 0x2000 * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
OPT_NICELEVEL = 0x4000 * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
};
int start_stop_daemon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int start_stop_daemon_main(int argc, char **argv)
{
unsigned opt;
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char *signame;
char *startas;
char *chuid;
#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
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applet_long_options = start_stop_daemon_longopts;
#endif
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/* Check required one context option was given */
opt_complementary = "K:S:K--S:S--K:m?p:K?xpun:S?xa";
opt = getopt32(argv, "KSbqma:n:s:u:c:x:p:"
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USE_FEATURE_START_STOP_DAEMON_FANCY("ovN:"),
// USE_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:"),
&startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
USE_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N)
// USE_FEATURE_START_STOP_DAEMON_FANCY(,&retry_arg)
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);
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quiet = (opt & OPT_QUIET) && !(opt & OPT_VERBOSE);
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if (opt & OPT_s) {
signal_nr = get_signum(signame);
if (signal_nr < 0) bb_show_usage();
}
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if (!(opt & OPT_a))
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startas = execname;
// USE_FEATURE_START_STOP_DAEMON_FANCY(
// if (retry_arg)
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// retries = xatoi_u(retry_arg);
// )
argc -= optind;
argv += optind;
if (userspec) {
user_id = bb_strtou(userspec, NULL, 10);
if (errno)
user_id = xuname2uid(userspec);
}
if (opt & CTX_STOP) {
int i = do_stop();
return (opt & OPT_OKNODO) ? 0 : (i <= 0);
}
do_procinit();
if (found) {
if (!quiet)
printf("%s already running\n%d\n", execname, found->pid);
return !(opt & OPT_OKNODO);
}
*--argv = startas;
if (opt & OPT_BACKGROUND) {
#if BB_MMU
bb_daemonize(0);
#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(0);
}
/* 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);
}
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if (opt & OPT_c) {
struct bb_uidgid_t ugid;
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
execv(startas, argv);
bb_perror_msg_and_die("cannot start %s", startas);
}