e125a683a — BusyBox

Subject

start_stop_daemon: add -test, fix -x to not match by inode, vastly improve hext text. (mostly by Roy Marples )

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Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

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debianutils/start_stop_daemon.c +86 -48 include/usage.h +51 -32

debianutils/start_stop_daemon.c+86 -48

@@ -23,15 +23,18 @@ If --start if given, start a new process unless a matching process was found.

	Options controlling process matching:
	-u,--user USERNAME\|UID Only consider this user's processes
-	-n,--name PROCESS_NAME Look for processes with matching argv[0]
-	or /proc/$PID/exe or /proc/$PID/stat (comm field).
+	-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 with matching /proc/$PID/exe.
-	Match is performed using device+inode.
+	-x,--exec EXECUTABLE Look for processes that were started with this
+	command in /proc/$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
+	If multiple conditions are specified, all must match.

	Options which are valid for --start only:
	-x,--exec EXECUTABLE Program to run (1st arg of execvp). Mandatory.
@@ -41,8 +44,13 @@ Options which are valid for --start only:
	-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!)
-	Misc options:
+
+	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
@@ -64,19 +72,21 @@ enum {
	CTX_START = (1 << 1),
	OPT_BACKGROUND = (1 << 2), // -b
	OPT_QUIET = (1 << 3), // -q
-	OPT_MAKEPID = (1 << 4), // -m
-	OPT_a = (1 << 5), // -a
-	OPT_n = (1 << 6), // -n
-	OPT_s = (1 << 7), // -s
-	OPT_u = (1 << 8), // -u
-	OPT_c = (1 << 9), // -c
-	OPT_x = (1 << 10), // -x
-	OPT_p = (1 << 11), // -p
-	OPT_OKNODO = (1 << 12) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
-	OPT_VERBOSE = (1 << 13) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
-	OPT_NICELEVEL = (1 << 14) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
+	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;
@@ -86,7 +96,6 @@ struct globals {
	char *pidfile;
	int user_id;
	smallint signal_nr;
-	struct stat execstat;
	};
	#define G ((struct globals)&bb_common_bufsiz1)
	#define found (G.found )
@@ -96,20 +105,23 @@ struct globals {
	#define pidfile (G.pidfile )
	#define user_id (G.user_id )
	#define signal_nr (G.signal_nr )
-	#define execstat (G.execstat )
	#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", pid);
+	sprintf(buf, "/proc/%u/exe", (unsigned)pid);
	if (stat(buf, &st) < 0)
	return 0;
	if (st.st_dev == execstat.st_dev
@@ -117,24 +129,29 @@ static int pid_is_exec(pid_t pid)
	return 1;
	return 0;
	}
+	#endif

-	static int pid_is_user(int pid)
+	static int pid_is_exec(pid_t pid)
	{
-	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_t)user_id);
+	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_cmd(pid_t pid)
+	static int pid_is_name(pid_t pid)
	{
-	char buf[256]; /* is it big enough? */
+	/* /proc/PID/stat is "PID (comm_15_bytes_max) ..." */
+	char buf[32]; /* should be enough */
	char p, pe;

-	sprintf(buf, "/proc/%u/stat", pid);
+	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 */
@@ -145,7 +162,23 @@ static int pid_is_cmd(pid_t pid)
	if (!pe)
	return 0;
	*pe = '\0';
-	return !strcmp(p, cmdname);
+	/* 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)
@@ -155,10 +188,10 @@ static void check(int pid)
	if (execname && !pid_is_exec(pid)) {
	return;
	}
-	if (userspec && !pid_is_user(pid)) {
+	if (cmdname && !pid_is_name(pid)) {
	return;
	}
-	if (cmdname && !pid_is_cmd(pid)) {
+	if (userspec && !pid_is_user(pid)) {
	return;
	}
	p = xmalloc(sizeof(*p));
@@ -195,10 +228,11 @@ static void do_procinit(void)
	procdir = xopendir("/proc");

	pid = 0;
-	while(1) {
+	while (1) {
	errno = 0; /* clear any previous error */
	entry = readdir(procdir);
-	// TODO: check for exact errno(s) which mean that we got stale entry
+	// 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 */
@@ -225,12 +259,13 @@ static int do_stop(void)
	} else if (execname) {
	if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(execname);
	if (!ENABLE_FEATURE_CLEAN_UP) what = execname;
-	} else if (pidfile)
+	} else if (pidfile) {
	what = xasprintf("process in pidfile '%s'", pidfile);
-	else if (userspec)
+	} else if (userspec) {
	what = xasprintf("process(es) owned by '%s'", userspec);
-	else
+	} else {
	bb_error_msg_and_die("internal error, please report");
+	}

	if (!found) {
	if (!QUIET)
@@ -239,18 +274,18 @@ static int do_stop(void)
	goto ret;
	}
	for (p = found; p; p = p->next) {
-	if (kill(p->pid, signal_nr) == 0) {
-	p->pid = - p->pid;
+	if (TEST \|\| kill(p->pid, signal_nr) == 0) {
	killed++;
	} else {
-	bb_perror_msg("warning: killing process %u", p->pid);
+	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 < 0)
-	printf(" %u", - p->pid);
+	if (p->pid)
+	printf(" %u", (unsigned)p->pid);
	puts(")");
	}
	ret:
@@ -265,6 +300,7 @@ static const char start_stop_daemon_longopts[] ALIGN1 =
	"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"
@@ -291,6 +327,7 @@ int start_stop_daemon_main(int argc ATTRIBUTE_UNUSED, char **argv)
	char *signame;
	char *startas;
	char *chuid;
+	struct stat execstat;
	#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
	// char *retry_arg = NULL;
	// int retries = -1;
@@ -310,7 +347,7 @@ int start_stop_daemon_main(int argc ATTRIBUTE_UNUSED, char **argv)
	/* -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, "KSbqma:n:s:u:c:x:p:"
+	opt = getopt32(argv, "KSbqtma:n:s:u:c:x:p:"
	USE_FEATURE_START_STOP_DAEMON_FANCY("ovN:"),
	// USE_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:"),
	&startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
@@ -338,9 +375,6 @@ int start_stop_daemon_main(int argc ATTRIBUTE_UNUSED, char **argv)
	if (errno)
	user_id = xuname2uid(userspec);
	}
-	if (execname)
-	xstat(execname, &execstat);
-
	do_procinit(); /* Both start and stop needs to know current processes */

	if (opt & CTX_STOP) {
@@ -353,6 +387,10 @@ int start_stop_daemon_main(int argc ATTRIBUTE_UNUSED, char **argv)
	printf("%s already running\n%d\n", execname, found->pid);
	return !(opt & OPT_OKNODO);
	}
+
+	if (execname)
+	xstat(execname, &execstat);
+
	*--argv = startas;
	if (opt & OPT_BACKGROUND) {
	#if BB_MMU

include/usage.h+51 -32

@@ -3613,46 +3613,65 @@
	USE_GETOPT_LONG("--start\|--stop") SKIP_GETOPT_LONG("-S\|-K") \
	"] ... [-- arguments...]"
	#define start_stop_daemon_full_usage "\n\n" \
-	"Start and stop services\n" \
-	"\nOptions:" \
+	"Search for matching processes, and then\n" \
+	"-S: stop all matching processes.\n" \
+	"-K: start a process unless a matching process is found.\n" \
	USE_GETOPT_LONG( \
-	"\n -S,--start Start" \
-	"\n -K,--stop Stop" \
-	"\n -a,--startas pathname Start process specified by pathname" \
-	"\n -b,--background Put process into background" \
-	"\n -u,--user username\|uid Stop this user's processes" \
-	"\n -x,--exec executable Program to either start or check" \
-	"\n -n,--name process-name Stop processes with this name" \
-	"\n -p,--pidfile pid-file Save or load pid using a pid-file" \
-	"\n -m,--make-pidfile Create the -p file and enter pid in it" \
-	"\n -q,--quiet Quiet" \
+	"\nProcess matching:" \
+	"\n -u,--user USERNAME\|UID Match only this user's processes" \
+	"\n -n,--name NAME Match processes with NAME" \
+	"\n in comm field in /proc/PID/stat" \
+	"\n -x,--exec EXECUTABLE Match processes with this command" \
+	"\n in /proc/PID/cmdline" \
+	"\n -p,--pidfile FILE Match a process with PID from the file" \
+	"\n All specified conditions must match" \
+	"\n-K only:" \
+	"\n -x,--exec EXECUTABLE Program to run" \
+	"\n -a,--startas NAME Zeroth argument" \
+	"\n -b,--background Background" \
	USE_FEATURE_START_STOP_DAEMON_FANCY( \
-	"\n -o,--oknodo Exit status 0 if nothing done" \
-	"\n -v,--verbose Verbose" \
-	"\n -N,--nicelevel N Add N to process's nice level" \
+	"\n -N,--nicelevel N Change nice level" \
	) \
-	"\n -s,--signal signal Signal to send (default TERM)" \
-	"\n -c,--chuid user[:[grp]] Change to specified user/group" \
+	"\n -c,--chuid USER[:[GRP]] Change to user/group" \
+	"\n -m,--make-pidfile Write PID to the pidfile specified by -p" \
+	"\n-S only:" \
+	"\n -s,--signal SIG Signal to send" \
+	"\n -t,--test Match only, exit with 0 if a process is found" \
+	"\nOther:" \
+	USE_FEATURE_START_STOP_DAEMON_FANCY( \
+	"\n -o,--oknodo Exit with status 0 if nothing is done" \
+	"\n -q,--quiet Quiet" \
+	) \
+	"\n -v,--verbose Verbose" \
	) \
	SKIP_GETOPT_LONG( \
-	"\n -S Start" \
-	"\n -K Stop" \
-	"\n -a pathname Start process specified by pathname" \
-	"\n -b Put process into background" \
-	"\n -u username\|uid Stop this user's processes" \
-	"\n -x executable Program to either start or check" \
-	"\n -n process-name Stop processes with this name" \
-	"\n -p pid-file Save or load pid using a pid-file" \
-	"\n -m Create the -p file and enter pid in it" \
-	"\n -q Quiet" \
+	"\nProcess matching:" \
+	"\n -u USERNAME\|UID Match only this user's processes" \
+	"\n -n NAME Match processes with NAME" \
+	"\n in comm field in /proc/PID/stat" \
+	"\n -x EXECUTABLE Match processes with this command" \
+	"\n command in /proc/PID/cmdline" \
+	"\n -p FILE Match a process with PID from the file" \
+	"\n All specified conditions must match" \
+	"\n-K only:" \
+	"\n -x EXECUTABLE Program to run" \
+	"\n -a NAME Zeroth argument" \
+	"\n -b Background" \
+	USE_FEATURE_START_STOP_DAEMON_FANCY( \
+	"\n -N N Change nice level" \
+	) \
+	"\n -c USER[:[GRP]] Change to user/group" \
+	"\n -m Write PID to the pidfile specified by -p" \
+	"\n-S only:" \
+	"\n -s SIG Signal to send" \
+	"\n -t Match only, exit with 0 if a process is found" \
+	"\nOther:" \
	USE_FEATURE_START_STOP_DAEMON_FANCY( \
-	"\n -o Exit status 0 if nothing done" \
+	"\n -o Exit with status 0 if nothing is done" \
+	"\n -q Quiet" \
+	) \
	"\n -v Verbose" \
-	"\n -N N Add N to process's nice level" \
	) \
-	"\n -s signal Signal to send (default TERM)" \
-	"\n -c user[:[grp]] Change to specified user/group" \
-	)

	#define stat_trivial_usage \
	"[OPTION] FILE..."