540 lines
16 KiB
C
540 lines
16 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini start-stop-daemon implementation(s) for busybox
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*
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* Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
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* Adapted for busybox David Kimdon <dwhedon@gordian.com>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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/*
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This is how it is supposed to work:
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start-stop-daemon [OPTIONS] [--start|--stop] [[--] arguments...]
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One (only) of these must be given:
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-S,--start Start
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-K,--stop Stop
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Search for matching processes.
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If --stop is given, stop all matching processes (by sending a signal).
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If --start is given, start a new process unless a matching process was found.
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Options controlling process matching
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(if multiple conditions are specified, all must match):
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-u,--user USERNAME|UID Only consider this user's processes
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-n,--name PROCESS_NAME Look for processes by matching PROCESS_NAME
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with comm field in /proc/$PID/stat.
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Only basename is compared:
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"ntpd" == "./ntpd" == "/path/to/ntpd".
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[TODO: can PROCESS_NAME be a full pathname? Should we require full match then
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with /proc/$PID/exe or argv[0] (comm can't be matched, it never contains path)]
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-x,--exec EXECUTABLE Look for processes that were started with this
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command in /proc/$PID/exe and /proc/$PID/cmdline
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(/proc/$PID/cmdline is a bbox extension)
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Unlike -n, we match against the full path:
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"ntpd" != "./ntpd" != "/path/to/ntpd"
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-p,--pidfile PID_FILE Look for processes with PID from this file
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Options which are valid for --start only:
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-x,--exec EXECUTABLE Program to run (1st arg of execvp). Mandatory.
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-a,--startas NAME argv[0] (defaults to EXECUTABLE)
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-b,--background Put process into background
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-N,--nicelevel N Add N to process' nice level
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-c,--chuid USER[:[GRP]] Change to specified user [and group]
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-m,--make-pidfile Write PID to the pidfile
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(both -m and -p must be given!)
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Options which are valid for --stop only:
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-s,--signal SIG Signal to send (default:TERM)
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-t,--test Exit with status 0 if process is found
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(we don't actually start or stop daemons)
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Misc options:
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-o,--oknodo Exit with status 0 if nothing is done
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-q,--quiet Quiet
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-v,--verbose Verbose
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*/
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//config:config START_STOP_DAEMON
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//config: bool "start-stop-daemon (12 kb)"
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//config: default y
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//config: help
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//config: start-stop-daemon is used to control the creation and
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//config: termination of system-level processes, usually the ones
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//config: started during the startup of the system.
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//config:
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//config:config FEATURE_START_STOP_DAEMON_LONG_OPTIONS
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//config: bool "Enable long options"
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//config: default y
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//config: depends on START_STOP_DAEMON && LONG_OPTS
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//config:
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//config:config FEATURE_START_STOP_DAEMON_FANCY
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//config: bool "Support additional arguments"
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//config: default y
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//config: depends on START_STOP_DAEMON
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//config: help
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//config: -o|--oknodo ignored since we exit with 0 anyway
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//config: -v|--verbose
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//config: -N|--nicelevel N
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//applet:IF_START_STOP_DAEMON(APPLET_ODDNAME(start-stop-daemon, start_stop_daemon, BB_DIR_SBIN, BB_SUID_DROP, start_stop_daemon))
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/* not NOEXEC: uses bb_common_bufsiz1 */
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//kbuild:lib-$(CONFIG_START_STOP_DAEMON) += start_stop_daemon.o
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//usage:#define start_stop_daemon_trivial_usage
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//usage: "[OPTIONS] [-S|-K] ... [-- ARGS...]"
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//usage:#define start_stop_daemon_full_usage "\n\n"
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//usage: "Search for matching processes, and then\n"
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//usage: "-K: stop all matching processes\n"
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//usage: "-S: start a process unless a matching process is found\n"
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//usage: "\nProcess matching:"
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//usage: "\n -u USERNAME|UID Match only this user's processes"
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//usage: "\n -n NAME Match processes with NAME"
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//usage: "\n in comm field in /proc/PID/stat"
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//usage: "\n -x EXECUTABLE Match processes with this command"
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//usage: "\n command in /proc/PID/cmdline"
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//usage: "\n -p FILE Match a process with PID from FILE"
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//usage: "\n All specified conditions must match"
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//usage: "\n-S only:"
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//usage: "\n -x EXECUTABLE Program to run"
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//usage: "\n -a NAME Zeroth argument"
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//usage: "\n -b Background"
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//usage: IF_FEATURE_START_STOP_DAEMON_FANCY(
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//usage: "\n -N N Change nice level"
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//usage: )
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//usage: "\n -c USER[:[GRP]] Change user/group"
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//usage: "\n -m Write PID to pidfile specified by -p"
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//usage: "\n-K only:"
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//usage: "\n -s SIG Signal to send"
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//usage: "\n -t Match only, exit with 0 if found"
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//usage: "\nOther:"
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//usage: IF_FEATURE_START_STOP_DAEMON_FANCY(
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//usage: "\n -o Exit with status 0 if nothing is done"
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//usage: "\n -v Verbose"
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//usage: )
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//usage: "\n -q Quiet"
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/* Override ENABLE_FEATURE_PIDFILE */
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#define WANT_PIDFILE 1
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#include "libbb.h"
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#include "common_bufsiz.h"
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struct pid_list {
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struct pid_list *next;
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pid_t pid;
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};
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enum {
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CTX_STOP = (1 << 0),
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CTX_START = (1 << 1),
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OPT_BACKGROUND = (1 << 2), // -b
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OPT_QUIET = (1 << 3), // -q
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OPT_TEST = (1 << 4), // -t
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OPT_MAKEPID = (1 << 5), // -m
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OPT_a = (1 << 6), // -a
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OPT_n = (1 << 7), // -n
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OPT_s = (1 << 8), // -s
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OPT_u = (1 << 9), // -u
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OPT_c = (1 << 10), // -c
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OPT_x = (1 << 11), // -x
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OPT_p = (1 << 12), // -p
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OPT_OKNODO = (1 << 13) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
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OPT_VERBOSE = (1 << 14) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
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OPT_NICELEVEL = (1 << 15) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
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};
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#define QUIET (option_mask32 & OPT_QUIET)
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#define TEST (option_mask32 & OPT_TEST)
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struct globals {
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struct pid_list *found_procs;
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char *userspec;
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char *cmdname;
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char *execname;
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char *pidfile;
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char *execname_cmpbuf;
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unsigned execname_sizeof;
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int user_id;
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smallint signal_nr;
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} FIX_ALIASING;
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#define G (*(struct globals*)bb_common_bufsiz1)
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#define userspec (G.userspec )
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#define cmdname (G.cmdname )
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#define execname (G.execname )
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#define pidfile (G.pidfile )
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#define user_id (G.user_id )
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#define signal_nr (G.signal_nr )
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#define INIT_G() do { \
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setup_common_bufsiz(); \
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user_id = -1; \
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signal_nr = 15; \
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} while (0)
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#ifdef OLDER_VERSION_OF_X
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/* -x,--exec EXECUTABLE
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* Look for processes with matching /proc/$PID/exe.
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* Match is performed using device+inode.
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*/
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static int pid_is_exec(pid_t pid)
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{
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struct stat st;
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char buf[sizeof("/proc/%u/exe") + sizeof(int)*3];
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sprintf(buf, "/proc/%u/exe", (unsigned)pid);
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if (stat(buf, &st) < 0)
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return 0;
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if (st.st_dev == execstat.st_dev
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&& st.st_ino == execstat.st_ino)
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return 1;
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return 0;
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}
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#endif
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static int pid_is_exec(pid_t pid)
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{
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ssize_t bytes;
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char buf[sizeof("/proc/%u/cmdline") + sizeof(int)*3];
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char *procname, *exelink;
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int match;
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procname = buf + sprintf(buf, "/proc/%u/exe", (unsigned)pid) - 3;
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exelink = xmalloc_readlink(buf);
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match = (exelink && strcmp(execname, exelink) == 0);
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free(exelink);
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if (match)
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return match;
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strcpy(procname, "cmdline");
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bytes = open_read_close(buf, G.execname_cmpbuf, G.execname_sizeof);
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if (bytes > 0) {
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G.execname_cmpbuf[bytes] = '\0';
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return strcmp(execname, G.execname_cmpbuf) == 0;
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}
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return 0;
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}
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static int pid_is_name(pid_t pid)
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{
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/* /proc/PID/stat is "PID (comm_15_bytes_max) ..." */
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char buf[32]; /* should be enough */
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char *p, *pe;
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sprintf(buf, "/proc/%u/stat", (unsigned)pid);
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if (open_read_close(buf, buf, sizeof(buf) - 1) < 0)
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return 0;
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buf[sizeof(buf) - 1] = '\0'; /* paranoia */
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p = strchr(buf, '(');
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if (!p)
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return 0;
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pe = strrchr(++p, ')');
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if (!pe)
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return 0;
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*pe = '\0';
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/* we require comm to match and to not be truncated */
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/* in Linux, if comm is 15 chars, it may be a truncated
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* name, so we don't allow that to match */
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if (strlen(p) >= COMM_LEN - 1) /* COMM_LEN is 16 */
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return 0;
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return strcmp(p, cmdname) == 0;
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}
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static int pid_is_user(int pid)
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{
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struct stat sb;
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char buf[sizeof("/proc/") + sizeof(int)*3];
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sprintf(buf, "/proc/%u", (unsigned)pid);
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if (stat(buf, &sb) != 0)
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return 0;
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return (sb.st_uid == (uid_t)user_id);
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}
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static void check(int pid)
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{
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struct pid_list *p;
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if (execname && !pid_is_exec(pid)) {
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return;
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}
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if (cmdname && !pid_is_name(pid)) {
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return;
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}
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if (userspec && !pid_is_user(pid)) {
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return;
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}
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p = xmalloc(sizeof(*p));
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p->next = G.found_procs;
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p->pid = pid;
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G.found_procs = p;
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}
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static void do_pidfile(void)
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{
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FILE *f;
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unsigned pid;
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f = fopen_for_read(pidfile);
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if (f) {
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if (fscanf(f, "%u", &pid) == 1)
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check(pid);
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fclose(f);
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} else if (errno != ENOENT)
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bb_perror_msg_and_die("open pidfile %s", pidfile);
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}
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static void do_procinit(void)
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{
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DIR *procdir;
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struct dirent *entry;
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int pid;
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if (pidfile) {
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do_pidfile();
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return;
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}
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procdir = xopendir("/proc");
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pid = 0;
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while (1) {
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errno = 0; /* clear any previous error */
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entry = readdir(procdir);
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// TODO: this check is too generic, it's better
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// to check for exact errno(s) which mean that we got stale entry
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if (errno) /* Stale entry, process has died after opendir */
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continue;
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if (!entry) /* EOF, no more entries */
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break;
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pid = bb_strtou(entry->d_name, NULL, 10);
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if (errno) /* NaN */
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continue;
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check(pid);
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}
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closedir(procdir);
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if (!pid)
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bb_error_msg_and_die("nothing in /proc - not mounted?");
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}
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static int do_stop(void)
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{
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char *what;
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struct pid_list *p;
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int killed = 0;
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if (cmdname) {
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if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(cmdname);
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if (!ENABLE_FEATURE_CLEAN_UP) what = cmdname;
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} else if (execname) {
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if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(execname);
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if (!ENABLE_FEATURE_CLEAN_UP) what = execname;
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} else if (pidfile) {
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what = xasprintf("process in pidfile '%s'", pidfile);
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} else if (userspec) {
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what = xasprintf("process(es) owned by '%s'", userspec);
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} else {
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bb_error_msg_and_die("internal error, please report");
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}
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if (!G.found_procs) {
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if (!QUIET)
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printf("no %s found; none killed\n", what);
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killed = -1;
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goto ret;
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}
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for (p = G.found_procs; p; p = p->next) {
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if (kill(p->pid, TEST ? 0 : signal_nr) == 0) {
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killed++;
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} else {
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bb_perror_msg("warning: killing process %u", (unsigned)p->pid);
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p->pid = 0;
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if (TEST) {
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/* Example: -K --test --pidfile PIDFILE detected
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* that PIDFILE's pid doesn't exist */
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killed = -1;
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goto ret;
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}
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}
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}
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if (!QUIET && killed) {
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printf("stopped %s (pid", what);
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for (p = G.found_procs; p; p = p->next)
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if (p->pid)
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printf(" %u", (unsigned)p->pid);
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puts(")");
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}
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ret:
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if (ENABLE_FEATURE_CLEAN_UP)
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free(what);
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return killed;
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}
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#if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
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static const char start_stop_daemon_longopts[] ALIGN1 =
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"stop\0" No_argument "K"
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"start\0" No_argument "S"
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"background\0" No_argument "b"
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"quiet\0" No_argument "q"
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"test\0" No_argument "t"
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"make-pidfile\0" No_argument "m"
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# if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
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"oknodo\0" No_argument "o"
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"verbose\0" No_argument "v"
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"nicelevel\0" Required_argument "N"
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# endif
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"startas\0" Required_argument "a"
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"name\0" Required_argument "n"
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"signal\0" Required_argument "s"
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"user\0" Required_argument "u"
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"chuid\0" Required_argument "c"
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"exec\0" Required_argument "x"
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"pidfile\0" Required_argument "p"
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# if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
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"retry\0" Required_argument "R"
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# endif
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;
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# define GETOPT32 getopt32long
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# define LONGOPTS start_stop_daemon_longopts,
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#else
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# define GETOPT32 getopt32
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# define LONGOPTS
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#endif
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int start_stop_daemon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int start_stop_daemon_main(int argc UNUSED_PARAM, char **argv)
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{
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unsigned opt;
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char *signame;
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char *startas;
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char *chuid;
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#ifdef OLDER_VERSION_OF_X
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struct stat execstat;
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#endif
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#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
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// char *retry_arg = NULL;
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// int retries = -1;
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char *opt_N;
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#endif
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INIT_G();
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opt = GETOPT32(argv, "^"
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"KSbqtma:n:s:u:c:x:p:"
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IF_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:")
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/* -K or -S is required; they are mutually exclusive */
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/* -p is required if -m is given */
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/* -xpun (at least one) is required if -K is given */
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/* -xa (at least one) is required if -S is given */
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/* -q turns off -v */
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"\0"
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"K:S:K--S:S--K:m?p:K?xpun:S?xa"
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IF_FEATURE_START_STOP_DAEMON_FANCY("q-v"),
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LONGOPTS
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&startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
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IF_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N)
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/* We accept and ignore -R <param> / --retry <param> */
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IF_FEATURE_START_STOP_DAEMON_FANCY(,NULL)
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);
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if (opt & OPT_s) {
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signal_nr = get_signum(signame);
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if (signal_nr < 0) bb_show_usage();
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}
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if (!(opt & OPT_a))
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startas = execname;
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if (!execname) /* in case -a is given and -x is not */
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execname = startas;
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if (execname) {
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G.execname_sizeof = strlen(execname) + 1;
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G.execname_cmpbuf = xmalloc(G.execname_sizeof + 1);
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}
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// IF_FEATURE_START_STOP_DAEMON_FANCY(
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// if (retry_arg)
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// retries = xatoi_positive(retry_arg);
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// )
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//argc -= optind;
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argv += optind;
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if (userspec) {
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user_id = bb_strtou(userspec, NULL, 10);
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if (errno)
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user_id = xuname2uid(userspec);
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}
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/* Both start and stop need to know current processes */
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do_procinit();
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if (opt & CTX_STOP) {
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int i = do_stop();
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return (opt & OPT_OKNODO) ? 0 : (i <= 0);
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}
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if (G.found_procs) {
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if (!QUIET)
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printf("%s is already running\n%u\n", execname, (unsigned)G.found_procs->pid);
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return !(opt & OPT_OKNODO);
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}
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#ifdef OLDER_VERSION_OF_X
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if (execname)
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|
xstat(execname, &execstat);
|
|
#endif
|
|
|
|
*--argv = startas;
|
|
if (opt & OPT_BACKGROUND) {
|
|
#if BB_MMU
|
|
bb_daemonize(DAEMON_DEVNULL_STDIO + DAEMON_CLOSE_EXTRA_FDS + DAEMON_DOUBLE_FORK);
|
|
/* DAEMON_DEVNULL_STDIO is superfluous -
|
|
* it's always done by bb_daemonize() */
|
|
#else
|
|
/* Daemons usually call bb_daemonize_or_rexec(), but SSD can do
|
|
* without: SSD is not itself a daemon, it _execs_ a daemon.
|
|
* The usual NOMMU problem of "child can't run indefinitely,
|
|
* it must exec" does not bite us: we exec anyway.
|
|
*/
|
|
pid_t pid = xvfork();
|
|
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 */
|
|
bb_daemon_helper(DAEMON_DEVNULL_STDIO + DAEMON_CLOSE_EXTRA_FDS);
|
|
#endif
|
|
}
|
|
if (opt & OPT_MAKEPID) {
|
|
/* User wants _us_ to make the pidfile */
|
|
write_pidfile(pidfile);
|
|
}
|
|
if (opt & OPT_c) {
|
|
struct bb_uidgid_t ugid;
|
|
parse_chown_usergroup_or_die(&ugid, chuid);
|
|
if (ugid.uid != (uid_t) -1L) {
|
|
struct passwd *pw = xgetpwuid(ugid.uid);
|
|
if (ugid.gid != (gid_t) -1L)
|
|
pw->pw_gid = ugid.gid;
|
|
/* initgroups, setgid, setuid: */
|
|
change_identity(pw);
|
|
} else if (ugid.gid != (gid_t) -1L) {
|
|
xsetgid(ugid.gid);
|
|
setgroups(1, &ugid.gid);
|
|
}
|
|
}
|
|
#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("can't execute '%s'", startas);
|
|
}
|