LXR busybox/debianutils/start_stop

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * Mini start-stop-daemon implementation(s) for busybox
   4 *
   5 * Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
   6 * Adapted for busybox David Kimdon <dwhedon@gordian.com>
   7 *
   8 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   9 */
  10
  11/*
  12This is how it is supposed to work:
  13
  14start-stop-daemon [OPTIONS] [--start|--stop] [[--] arguments...]
  15
  16One (only) of these must be given:
  17        -S,--start              Start
  18        -K,--stop               Stop
  19
  20Search for matching processes.
  21If --stop is given, stop all matching processes (by sending a signal).
  22If --start is given, start a new process unless a matching process was found.
  23
  24Options controlling process matching
  25(if multiple conditions are specified, all must match):
  26        -u,--user USERNAME|UID  Only consider this user's processes
  27        -n,--name PROCESS_NAME  Look for processes by matching PROCESS_NAME
  28                                with comm field in /proc/$PID/stat.
  29                                Only basename is compared:
  30                                "ntpd" == "./ntpd" == "/path/to/ntpd".
  31[TODO: can PROCESS_NAME be a full pathname? Should we require full match then
  32with /proc/$PID/exe or argv[0] (comm can't be matched, it never contains path)]
  33        -x,--exec EXECUTABLE    Look for processes that were started with this
  34                                command in /proc/$PID/cmdline.
  35                                Unlike -n, we match against the full path:
  36                                "ntpd" != "./ntpd" != "/path/to/ntpd"
  37        -p,--pidfile PID_FILE   Look for processes with PID from this file
  38
  39Options which are valid for --start only:
  40        -x,--exec EXECUTABLE    Program to run (1st arg of execvp). Mandatory.
  41        -a,--startas NAME       argv[0] (defaults to EXECUTABLE)
  42        -b,--background         Put process into background
  43        -N,--nicelevel N        Add N to process' nice level
  44        -c,--chuid USER[:[GRP]] Change to specified user [and group]
  45        -m,--make-pidfile       Write PID to the pidfile
  46                                (both -m and -p must be given!)
  47
  48Options which are valid for --stop only:
  49        -s,--signal SIG         Signal to send (default:TERM)
  50        -t,--test               Exit with status 0 if process is found
  51                                (we don't actually start or stop daemons)
  52
  53Misc options:
  54        -o,--oknodo             Exit with status 0 if nothing is done
  55        -q,--quiet              Quiet
  56        -v,--verbose            Verbose
  57*/
  58
  59#include <sys/resource.h>
  60
  61/* Override ENABLE_FEATURE_PIDFILE */
  62#define WANT_PIDFILE 1
  63#include "libbb.h"
  64
  65struct pid_list {
  66        struct pid_list *next;
  67        pid_t pid;
  68};
  69
  70enum {
  71        CTX_STOP       = (1 <<  0),
  72        CTX_START      = (1 <<  1),
  73        OPT_BACKGROUND = (1 <<  2), // -b
  74        OPT_QUIET      = (1 <<  3), // -q
  75        OPT_TEST       = (1 <<  4), // -t
  76        OPT_MAKEPID    = (1 <<  5), // -m
  77        OPT_a          = (1 <<  6), // -a
  78        OPT_n          = (1 <<  7), // -n
  79        OPT_s          = (1 <<  8), // -s
  80        OPT_u          = (1 <<  9), // -u
  81        OPT_c          = (1 << 10), // -c
  82        OPT_x          = (1 << 11), // -x
  83        OPT_p          = (1 << 12), // -p
  84        OPT_OKNODO     = (1 << 13) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
  85        OPT_VERBOSE    = (1 << 14) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
  86        OPT_NICELEVEL  = (1 << 15) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
  87};
  88#define QUIET (option_mask32 & OPT_QUIET)
  89#define TEST  (option_mask32 & OPT_TEST)
  90
  91struct globals {
  92        struct pid_list *found_procs;
  93        char *userspec;
  94        char *cmdname;
  95        char *execname;
  96        char *pidfile;
  97        char *execname_cmpbuf;
  98        unsigned execname_sizeof;
  99        int user_id;
 100        smallint signal_nr;
 101} FIX_ALIASING;
 102#define G (*(struct globals*)&bb_common_bufsiz1)
 103#define userspec          (G.userspec            )
 104#define cmdname           (G.cmdname             )
 105#define execname          (G.execname            )
 106#define pidfile           (G.pidfile             )
 107#define user_id           (G.user_id             )
 108#define signal_nr         (G.signal_nr           )
 109#define INIT_G() do { \
 110        user_id = -1; \
 111        signal_nr = 15; \
 112} while (0)
 113
 114#ifdef OLDER_VERSION_OF_X
 115/* -x,--exec EXECUTABLE
 116 * Look for processes with matching /proc/$PID/exe.
 117 * Match is performed using device+inode.
 118 */
 119static int pid_is_exec(pid_t pid)
 120{
 121        struct stat st;
 122        char buf[sizeof("/proc/%u/exe") + sizeof(int)*3];
 123
 124        sprintf(buf, "/proc/%u/exe", (unsigned)pid);
 125        if (stat(buf, &st) < 0)
 126                return 0;
 127        if (st.st_dev == execstat.st_dev
 128         && st.st_ino == execstat.st_ino)
 129                return 1;
 130        return 0;
 131}
 132#endif
 133
 134static int pid_is_exec(pid_t pid)
 135{
 136        ssize_t bytes;
 137        char buf[sizeof("/proc/%u/cmdline") + sizeof(int)*3];
 138
 139        sprintf(buf, "/proc/%u/cmdline", (unsigned)pid);
 140        bytes = open_read_close(buf, G.execname_cmpbuf, G.execname_sizeof);
 141        if (bytes > 0) {
 142                G.execname_cmpbuf[bytes] = '\0';
 143                return strcmp(execname, G.execname_cmpbuf) == 0;
 144        }
 145        return 0;
 146}
 147
 148static int pid_is_name(pid_t pid)
 149{
 150        /* /proc/PID/stat is "PID (comm_15_bytes_max) ..." */
 151        char buf[32]; /* should be enough */
 152        char *p, *pe;
 153
 154        sprintf(buf, "/proc/%u/stat", (unsigned)pid);
 155        if (open_read_close(buf, buf, sizeof(buf) - 1) < 0)
 156                return 0;
 157        buf[sizeof(buf) - 1] = '\0'; /* paranoia */
 158        p = strchr(buf, '(');
 159        if (!p)
 160                return 0;
 161        pe = strrchr(++p, ')');
 162        if (!pe)
 163                return 0;
 164        *pe = '\0';
 165        /* we require comm to match and to not be truncated */
 166        /* in Linux, if comm is 15 chars, it may be a truncated
 167         * name, so we don't allow that to match */
 168        if (strlen(p) >= COMM_LEN - 1) /* COMM_LEN is 16 */
 169                return 0;
 170        return strcmp(p, cmdname) == 0;
 171}
 172
 173static int pid_is_user(int pid)
 174{
 175        struct stat sb;
 176        char buf[sizeof("/proc/") + sizeof(int)*3];
 177
 178        sprintf(buf, "/proc/%u", (unsigned)pid);
 179        if (stat(buf, &sb) != 0)
 180                return 0;
 181        return (sb.st_uid == (uid_t)user_id);
 182}
 183
 184static void check(int pid)
 185{
 186        struct pid_list *p;
 187
 188        if (execname && !pid_is_exec(pid)) {
 189                return;
 190        }
 191        if (cmdname && !pid_is_name(pid)) {
 192                return;
 193        }
 194        if (userspec && !pid_is_user(pid)) {
 195                return;
 196        }
 197        p = xmalloc(sizeof(*p));
 198        p->next = G.found_procs;
 199        p->pid = pid;
 200        G.found_procs = p;
 201}
 202
 203static void do_pidfile(void)
 204{
 205        FILE *f;
 206        unsigned pid;
 207
 208        f = fopen_for_read(pidfile);
 209        if (f) {
 210                if (fscanf(f, "%u", &pid) == 1)
 211                        check(pid);
 212                fclose(f);
 213        } else if (errno != ENOENT)
 214                bb_perror_msg_and_die("open pidfile %s", pidfile);
 215}
 216
 217static void do_procinit(void)
 218{
 219        DIR *procdir;
 220        struct dirent *entry;
 221        int pid;
 222
 223        if (pidfile) {
 224                do_pidfile();
 225                return;
 226        }
 227
 228        procdir = xopendir("/proc");
 229
 230        pid = 0;
 231        while (1) {
 232                errno = 0; /* clear any previous error */
 233                entry = readdir(procdir);
 234// TODO: this check is too generic, it's better
 235// to check for exact errno(s) which mean that we got stale entry
 236                if (errno) /* Stale entry, process has died after opendir */
 237                        continue;
 238                if (!entry) /* EOF, no more entries */
 239                        break;
 240                pid = bb_strtou(entry->d_name, NULL, 10);
 241                if (errno) /* NaN */
 242                        continue;
 243                check(pid);
 244        }
 245        closedir(procdir);
 246        if (!pid)
 247                bb_error_msg_and_die("nothing in /proc - not mounted?");
 248}
 249
 250static int do_stop(void)
 251{
 252        char *what;
 253        struct pid_list *p;
 254        int killed = 0;
 255
 256        if (cmdname) {
 257                if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(cmdname);
 258                if (!ENABLE_FEATURE_CLEAN_UP) what = cmdname;
 259        } else if (execname) {
 260                if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(execname);
 261                if (!ENABLE_FEATURE_CLEAN_UP) what = execname;
 262        } else if (pidfile) {
 263                what = xasprintf("process in pidfile '%s'", pidfile);
 264        } else if (userspec) {
 265                what = xasprintf("process(es) owned by '%s'", userspec);
 266        } else {
 267                bb_error_msg_and_die("internal error, please report");
 268        }
 269
 270        if (!G.found_procs) {
 271                if (!QUIET)
 272                        printf("no %s found; none killed\n", what);
 273                killed = -1;
 274                goto ret;
 275        }
 276        for (p = G.found_procs; p; p = p->next) {
 277                if (TEST || kill(p->pid, signal_nr) == 0) {
 278                        killed++;
 279                } else {
 280                        p->pid = 0;
 281                        bb_perror_msg("warning: killing process %u", (unsigned)p->pid);
 282                }
 283        }
 284        if (!QUIET && killed) {
 285                printf("stopped %s (pid", what);
 286                for (p = G.found_procs; p; p = p->next)
 287                        if (p->pid)
 288                                printf(" %u", (unsigned)p->pid);
 289                puts(")");
 290        }
 291 ret:
 292        if (ENABLE_FEATURE_CLEAN_UP)
 293                free(what);
 294        return killed;
 295}
 296
 297#if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
 298static const char start_stop_daemon_longopts[] ALIGN1 =
 299        "stop\0"         No_argument       "K"
 300        "start\0"        No_argument       "S"
 301        "background\0"   No_argument       "b"
 302        "quiet\0"        No_argument       "q"
 303        "test\0"         No_argument       "t"
 304        "make-pidfile\0" No_argument       "m"
 305#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
 306        "oknodo\0"       No_argument       "o"
 307        "verbose\0"      No_argument       "v"
 308        "nicelevel\0"    Required_argument "N"
 309#endif
 310        "startas\0"      Required_argument "a"
 311        "name\0"         Required_argument "n"
 312        "signal\0"       Required_argument "s"
 313        "user\0"         Required_argument "u"
 314        "chuid\0"        Required_argument "c"
 315        "exec\0"         Required_argument "x"
 316        "pidfile\0"      Required_argument "p"
 317#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
 318        "retry\0"        Required_argument "R"
 319#endif
 320        ;
 321#endif
 322
 323int start_stop_daemon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 324int start_stop_daemon_main(int argc UNUSED_PARAM, char **argv)
 325{
 326        unsigned opt;
 327        char *signame;
 328        char *startas;
 329        char *chuid;
 330#ifdef OLDER_VERSION_OF_X
 331        struct stat execstat;
 332#endif
 333#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
 334//      char *retry_arg = NULL;
 335//      int retries = -1;
 336        char *opt_N;
 337#endif
 338
 339        INIT_G();
 340
 341#if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
 342        applet_long_options = start_stop_daemon_longopts;
 343#endif
 344
 345        /* -K or -S is required; they are mutually exclusive */
 346        /* -p is required if -m is given */
 347        /* -xpun (at least one) is required if -K is given */
 348        /* -xa (at least one) is required if -S is given */
 349        /* -q turns off -v */
 350        opt_complementary = "K:S:K--S:S--K:m?p:K?xpun:S?xa"
 351                IF_FEATURE_START_STOP_DAEMON_FANCY("q-v");
 352        opt = getopt32(argv, "KSbqtma:n:s:u:c:x:p:"
 353                IF_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:"),
 354                &startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
 355                IF_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N)
 356                /* We accept and ignore -R <param> / --retry <param> */
 357                IF_FEATURE_START_STOP_DAEMON_FANCY(,NULL)
 358        );
 359
 360        if (opt & OPT_s) {
 361                signal_nr = get_signum(signame);
 362                if (signal_nr < 0) bb_show_usage();
 363        }
 364
 365        if (!(opt & OPT_a))
 366                startas = execname;
 367        if (!execname) /* in case -a is given and -x is not */
 368                execname = startas;
 369        if (execname) {
 370                G.execname_sizeof = strlen(execname) + 1;
 371                G.execname_cmpbuf = xmalloc(G.execname_sizeof + 1);
 372        }
 373
 374//      IF_FEATURE_START_STOP_DAEMON_FANCY(
 375//              if (retry_arg)
 376//                      retries = xatoi_u(retry_arg);
 377//      )
 378        //argc -= optind;
 379        argv += optind;
 380
 381        if (userspec) {
 382                user_id = bb_strtou(userspec, NULL, 10);
 383                if (errno)
 384                        user_id = xuname2uid(userspec);
 385        }
 386        /* Both start and stop need to know current processes */
 387        do_procinit();
 388
 389        if (opt & CTX_STOP) {
 390                int i = do_stop();
 391                return (opt & OPT_OKNODO) ? 0 : (i <= 0);
 392        }
 393
 394        if (G.found_procs) {
 395                if (!QUIET)
 396                        printf("%s is already running\n%u\n", execname, (unsigned)G.found_procs->pid);
 397                return !(opt & OPT_OKNODO);
 398        }
 399
 400#ifdef OLDER_VERSION_OF_X
 401        if (execname)
 402                xstat(execname, &execstat);
 403#endif
 404
 405        *--argv = startas;
 406        if (opt & OPT_BACKGROUND) {
 407#if BB_MMU
 408                bb_daemonize(DAEMON_DEVNULL_STDIO + DAEMON_CLOSE_EXTRA_FDS);
 409                /* DAEMON_DEVNULL_STDIO is superfluous -
 410                 * it's always done by bb_daemonize() */
 411#else
 412                pid_t pid = xvfork();
 413                if (pid != 0) {
 414                        /* parent */
 415                        /* why _exit? the child may have changed the stack,
 416                         * so "return 0" may do bad things */
 417                        _exit(EXIT_SUCCESS);
 418                }
 419                /* Child */
 420                setsid(); /* detach from controlling tty */
 421                /* Redirect stdio to /dev/null, close extra FDs.
 422                 * We do not actually daemonize because of DAEMON_ONLY_SANITIZE */
 423                bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO
 424                        + DAEMON_CLOSE_EXTRA_FDS
 425                        + DAEMON_ONLY_SANITIZE,
 426                        NULL /* argv, unused */ );
 427#endif
 428        }
 429        if (opt & OPT_MAKEPID) {
 430                /* User wants _us_ to make the pidfile */
 431                write_pidfile(pidfile);
 432        }
 433        if (opt & OPT_c) {
 434                struct bb_uidgid_t ugid = { -1, -1 };
 435                parse_chown_usergroup_or_die(&ugid, chuid);
 436                if (ugid.gid != (gid_t) -1) xsetgid(ugid.gid);
 437                if (ugid.uid != (uid_t) -1) xsetuid(ugid.uid);
 438        }
 439#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
 440        if (opt & OPT_NICELEVEL) {
 441                /* Set process priority */
 442                int prio = getpriority(PRIO_PROCESS, 0) + xatoi_range(opt_N, INT_MIN/2, INT_MAX/2);
 443                if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
 444                        bb_perror_msg_and_die("setpriority(%d)", prio);
 445                }
 446        }
 447#endif
 448        execvp(startas, argv);
 449        bb_perror_msg_and_die("can't execute '%s'", startas);
 450}
 451