/* vi: set sw=4 ts=4: */ /* * Mini start-stop-daemon implementation(s) for busybox * * Written by Marek Michalkiewicz , * Adapted for busybox David Kimdon * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ /* This is how it is supposed to work: start-stop-daemon [OPTIONS] [--start|--stop] [[--] ARGS] One (only) of these must be given: -S,--start Start -K,--stop Stop -T,--status Check for the existence of a process, return exitcode (since version 1.16.1) 0 - program is running 1 - program is not running and the pid file exists 3 - program is not running 4 - can't determine program status 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/$PID/exe and /proc/$PID/cmdline (/proc/$PID/cmdline is a bbox extension) 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 --pid PID Look for process with this pid (since version 1.17.6) --ppid PPID Look for processes with parent pid (since version 1.17.7) Options which are valid for --start only: -x,--exec EXECUTABLE Program to run (1st arg of execvp). If no -x, EXECUTABLE is taken from ARGS[0] -a,--startas NAME argv[0] (defaults to EXECUTABLE) -b,--background Put process into background -O,--output FILE Redirect stdout and stderr to FILE when forcing the daemon into the background (since version 1.20.6). Requires --background and absolute pathname (tested with 1.21.22). Uses O_CREAT|O_APPEND! If execv fails, error message goes to FILE. -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!) -P,--procsched policy:priority This alters the process scheduler policy and priority of the process before starting it (since version 1.15.0). The priority can be optionally specified by appending a : followed by the value. The default priority is 0. The currently supported policy values are other, fifo and rr. -r,--chroot DIR Change directory and chroot to DIR before starting the process. Please note that the pidfile is also written after the chroot. -d,--chdir DIR Change directory to DIR before starting the process. This is done after the chroot if the -r|--chroot option is set. When not specified, start-stop-daemon will change directory to the root directory before starting the process. ^^^^ Gentoo does not have the default chdir("/"). Debian does. Tested -S with 1.21.22: "start-stop-daemon -S -x /bin/pwd" is the minimum needed to run pwd. "start-stop-daemon -S -a /bin/pwd -n pwd" works too. "start-stop-daemon -S -a /bin/pwd" does NOT work. Earlier versions were less picky (which? Or is it only Gentoo's clone?) 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) --remove-pidfile Used when stopping a program that does not remove its own pid file (since version 1.17.19). Requires -p PIDFILE? Misc options: -o,--oknodo Exit with status 0 if nothing is done -q,--quiet Quiet -v,--verbose Verbose */ //config:config START_STOP_DAEMON //config: bool "start-stop-daemon (12 kb)" //config: default y //config: help //config: start-stop-daemon is used to control the creation and //config: termination of system-level processes, usually the ones //config: started during the startup of the system. //config: //config:config FEATURE_START_STOP_DAEMON_LONG_OPTIONS //config: bool "Enable long options" //config: default y //config: depends on START_STOP_DAEMON && LONG_OPTS //config: //config:config FEATURE_START_STOP_DAEMON_FANCY //config: bool "Support additional arguments" //config: default y //config: depends on START_STOP_DAEMON //config: help //config: -o|--oknodo ignored since we exit with 0 anyway //config: -v|--verbose //config: -N|--nicelevel N //applet:IF_START_STOP_DAEMON(APPLET_ODDNAME(start-stop-daemon, start_stop_daemon, BB_DIR_SBIN, BB_SUID_DROP, start_stop_daemon)) /* not NOEXEC: uses bb_common_bufsiz1 */ //kbuild:lib-$(CONFIG_START_STOP_DAEMON) += start_stop_daemon.o //usage:#define start_stop_daemon_trivial_usage //usage: "-S|-K [OPTIONS] [-- ARGS]" //usage:#define start_stop_daemon_full_usage "\n\n" //usage: "Search for matching processes, and then\n" //usage: "-S: start a process unless a matching process is found\n" //usage: "-K: stop all matching processes\n" //usage: "\nProcess matching:" //usage: "\n -u USERNAME|UID Match only this user's processes" //usage: "\n -n NAME Match processes with NAME" //usage: "\n in comm field in /proc/PID/stat" //usage: "\n -x EXECUTABLE Match processes with this command" //usage: "\n in /proc/PID/cmdline" //usage: "\n -p FILE Match a process with PID from FILE" //usage: "\n All specified conditions must match" //usage: "\n-S only:" //usage: "\n -x EXECUTABLE Program to run" //usage: "\n -a NAME Zeroth argument" //usage: "\n -b Background" //usage: "\n -O FILE Append stdout and stderr to FILE" //usage: IF_FEATURE_START_STOP_DAEMON_FANCY( //usage: "\n -N N Change nice level" //usage: ) //usage: "\n -c USER[:[GRP]] Change user/group" //usage: "\n -d DIR Change to DIR" //usage: "\n -m Write PID to pidfile specified by -p" //usage: "\n-K only:" //usage: "\n -s SIG Signal to send" //usage: "\n -t Match only, exit with 0 if found" //usage: "\nOther:" //usage: IF_FEATURE_START_STOP_DAEMON_FANCY( //usage: "\n -o Exit with status 0 if nothing is done" //usage: "\n -v Verbose" //usage: "\n -q Quiet" //usage: ) /* Override ENABLE_FEATURE_PIDFILE */ #define WANT_PIDFILE 1 #include "libbb.h" #include "common_bufsiz.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_d = (1 << 11), // -d OPT_x = (1 << 12), // -x OPT_p = (1 << 13), // -p OPT_OUTPUT = (1 << 14), // -O OPT_OKNODO = (1 << 15) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o OPT_VERBOSE = (1 << 16) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v OPT_NICELEVEL = (1 << 17) * 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_procs; const char *userspec; const char *cmdname; const char *execname; const char *pidfile; char *execname_cmpbuf; unsigned execname_sizeof; int user_id; smallint signal_nr; #ifdef OLDER_VERSION_OF_X struct stat execstat; #endif } FIX_ALIASING; #define G (*(struct globals*)bb_common_bufsiz1) #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 { \ setup_common_bufsiz(); \ 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/%u/exe") + sizeof(int)*3]; sprintf(buf, "/proc/%u/exe", (unsigned)pid); if (stat(buf, &st) < 0) return 0; if (st.st_dev == G.execstat.st_dev && st.st_ino == G.execstat.st_ino) return 1; return 0; } #else static int pid_is_exec(pid_t pid) { ssize_t bytes; char buf[sizeof("/proc/%u/cmdline") + sizeof(int)*3]; char *procname, *exelink; int match; procname = buf + sprintf(buf, "/proc/%u/exe", (unsigned)pid) - 3; exelink = xmalloc_readlink(buf); match = (exelink && strcmp(execname, exelink) == 0); free(exelink); if (match) return match; strcpy(procname, "cmdline"); bytes = open_read_close(buf, G.execname_cmpbuf, G.execname_sizeof); if (bytes > 0) { G.execname_cmpbuf[bytes] = '\0'; return strcmp(execname, G.execname_cmpbuf) == 0; } return 0; } #endif 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 = G.found_procs; p->pid = pid; G.found_procs = 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_simple_error_msg_and_die("nothing in /proc - not mounted?"); } static int do_stop(void) { const 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_simple_error_msg_and_die("internal error, please report"); } if (!G.found_procs) { if (!QUIET) printf("no %s found; none killed\n", what); killed = -1; goto ret; } for (p = G.found_procs; p; p = p->next) { if (kill(p->pid, TEST ? 0 : signal_nr) == 0) { killed++; } else { bb_perror_msg("warning: killing process %u", (unsigned)p->pid); p->pid = 0; if (TEST) { /* Example: -K --test --pidfile PIDFILE detected * that PIDFILE's pid doesn't exist */ killed = -1; goto ret; } } } if (!QUIET && killed) { printf("stopped %s (pid", what); for (p = G.found_procs; p; p = p->next) if (p->pid) printf(" %u", (unsigned)p->pid); puts(")"); } ret: if (ENABLE_FEATURE_CLEAN_UP) free((char *)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" "output\0" Required_argument "O" # 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" "chdir\0" Required_argument "d" "exec\0" Required_argument "x" "pidfile\0" Required_argument "p" # if ENABLE_FEATURE_START_STOP_DAEMON_FANCY "retry\0" Required_argument "R" # endif ; # define GETOPT32 getopt32long # define LONGOPTS start_stop_daemon_longopts, #else # define GETOPT32 getopt32 # define LONGOPTS #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; const char *signame; const char *startas = NULL; char *chuid; const char *chdir; const char *output = NULL; #if ENABLE_FEATURE_START_STOP_DAEMON_FANCY // const char *retry_arg = NULL; // int retries = -1; const char *opt_N; #endif INIT_G(); opt = GETOPT32(argv, "^" "KSbqtma:n:s:u:c:d:x:p:O:" IF_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:") "\0" "K:S:K--S:S--K" /* -K or -S is required; they are mutually exclusive */ ":m?p" /* -p is required if -m is given */ ":K?xpun" /* -xpun (at least one) is required if -K is given */ /* (the above does not seem to be enforced by Gentoo, it does nothing * if no matching is specified with -K, and it ignores ARGS * - does not take ARGS[0] as program name to kill) */ // ":S?xa" /* -xa (at least one) is required if -S is given */ //Gentoo clone: "start-stop-daemon -S -- sleep 5" is a valid invocation IF_FEATURE_START_STOP_DAEMON_FANCY(":q-v") /* -q turns off -v */ , LONGOPTS &startas, &cmdname, &signame, &userspec, &chuid, &chdir, &execname, &pidfile, &output IF_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N) /* We accept and ignore -R / --retry */ IF_FEATURE_START_STOP_DAEMON_FANCY(,NULL) ); //-O requires --background and absolute pathname (tested with 1.21.22). //We don't bother requiring that (smaller code): //#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY // if ((opt & OPT_OUTPUT) && !(opt & OPT_BACKGROUND)) // bb_show_usage(); //#endif if (opt & OPT_s) { signal_nr = get_signum(signame); if (signal_nr < 0) bb_show_usage(); } //argc -= optind; argv += optind; // ARGS contains zeroth arg if -x/-a is not given, else it starts with 1st arg. // These will try to execute "[/bin/]sleep 5": // "start-stop-daemon -S -- sleep 5" // "start-stop-daemon -S -x /bin/sleep -- 5" // "start-stop-daemon -S -a sleep -- 5" // NB: -n option does _not_ behave in this way: this will try to execute "5": // "start-stop-daemon -S -n sleep -- 5" if (opt & CTX_START) { if (!execname) { /* -x is not given */ execname = startas; if (!execname) { /* neither -x nor -a is given */ execname = argv[0]; if (!execname) bb_show_usage(); argv++; } } if (!startas) /* -a is not given: use -x EXECUTABLE or argv[0] */ startas = execname; *--argv = (char *)startas; } if (execname) { G.execname_sizeof = strlen(execname) + 1; G.execname_cmpbuf = xmalloc(G.execname_sizeof + 1); } // IF_FEATURE_START_STOP_DAEMON_FANCY( // if (retry_arg) // retries = xatoi_positive(retry_arg); // ) 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); } /* else: CTX_START (-S). execname can't be NULL. */ if (G.found_procs) { if (!QUIET) printf("%s is already running\n", execname); return !(opt & OPT_OKNODO); } #ifdef OLDER_VERSION_OF_X if (execname) xstat(execname, &G.execstat); #endif if (opt & OPT_BACKGROUND) { /* 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. * * bb_daemonize(DAEMON_DEVNULL_STDIO | DAEMON_CLOSE_EXTRA_FDS | DAEMON_DOUBLE_FORK) * can be used on MMU systems, but use of vfork() * is preferable since we want to create pidfile * _before_ parent returns, and vfork() on Linux * ensures that (by blocking parent until exec in the child). */ 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_SUCCESS(); } /* Child */ setsid(); /* detach from controlling tty */ /* Redirect stdin to /dev/null, close extra FDs */ /* Testcase: "start-stop-daemon -Sb -d /does/not/exist usleep 1" should not eat error message */ bb_daemon_helper(DAEMON_DEVNULL_STDIN + DAEMON_CLOSE_EXTRA_FDS); if (!output) output = bb_dev_null; /* redirect output just before execv */ /* On Linux, session leader can acquire ctty * unknowingly, by opening a tty. * Prevent this: stop being a session leader. */ pid = xvfork(); if (pid != 0) _exit_SUCCESS(); /* Parent */ } if (opt & OPT_MAKEPID) { /* User wants _us_ to make the pidfile */ write_pidfile(pidfile); } #if ENABLE_FEATURE_START_STOP_DAEMON_FANCY if (opt & OPT_NICELEVEL) { /* Set process priority (must be before OPT_c) */ 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 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 (opt & OPT_d) { xchdir(chdir); } if (output) { int outfd = xopen(output, O_WRONLY | O_CREAT | O_APPEND); xmove_fd(outfd, STDOUT_FILENO); xdup2(STDOUT_FILENO, STDERR_FILENO); /* on execv error, the message goes to -O file. This is intended */ } /* Try: * strace -oLOG start-stop-daemon -S -x /bin/usleep -a qwerty 500000 * should exec "/bin/usleep", but argv[0] should be "qwerty": */ execvp(execname, argv); bb_perror_msg_and_die("can't execute '%s'", startas); }