networking/inetd.c

   1 /*
   2  * Copyright (c) 1983,1991 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * David A. Holland.
   7  *
   8  * Busybox port by Vladimir Oleynik (C) 2001-2003 <dzo@simtreas.ru>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  *
  24  */
  25
  26 /*
  27  * Inetd - Internet super-server
  28  *
  29  * This program invokes all internet services as needed.
  30  * connection-oriented services are invoked each time a
  31  * connection is made, by creating a process.  This process
  32  * is passed the connection as file descriptor 0 and is
  33  * expected to do a getpeername to find out the source host
  34  * and port.
  35  *
  36  * Datagram oriented services are invoked when a datagram
  37  * arrives; a process is created and passed a pending message
  38  * on file descriptor 0.  Datagram servers may either connect
  39  * to their peer, freeing up the original socket for inetd
  40  * to receive further messages on, or ``take over the socket'',
  41  * processing all arriving datagrams and, eventually, timing
  42  * out.  The first type of server is said to be ``multi-threaded'';
  43  * the second type of server ``single-threaded''.
  44  *
  45  * Inetd uses a configuration file which is read at startup
  46  * and, possibly, at some later time in response to a hangup signal.
  47  * The configuration file is ``free format'' with fields given in the
  48  * order shown below.  Continuation lines for an entry must being with
  49  * a space or tab.  All fields must be present in each entry.
  50  *
  51  *      service name                    must be in /etc/services
  52  *      socket type                     stream/dgram/raw/rdm/seqpacket
  53  *      protocol                        must be in /etc/protocols
  54  *      wait/nowait[.max]               single-threaded/multi-threaded, max #
  55  *      user[.group]                    user/group to run daemon as
  56  *      server program                  full path name
  57  *      server program arguments        maximum of MAXARGS (20)
  58  *
  59  * RPC services unsuported
  60  *
  61  * Comment lines are indicated by a `#' in column 1.
  62  */
  63
  64 /*
  65  * Here's the scoop concerning the user.group feature:
  66  *
  67  * 1) No group listed.
  68  *
  69  *      a) for root:    NO setuid() or setgid() is done
  70  *
  71  *      b) nonroot:     setuid()
  72  *                      setgid(primary group as found in passwd)
  73  *                      initgroups(name, primary group)
  74  *
  75  * 2) set-group-option on.
  76  *
  77  *      a) for root:    NO setuid()
  78  *                      setgid(specified group)
  79  *                      setgroups(1, specified group)
  80  *
  81  *      b) nonroot:     setuid()
  82  *                      setgid(specified group)
  83  *                      initgroups(name, specified group)
  84  *
  85  * All supplementary groups are discarded at startup in case inetd was
  86  * run manually.
  87  */
  88
  89 #define __USE_BSD_SIGNAL
  90
  91 #include "busybox.h"
  92
  93 #include <sys/param.h>
  94 #include <sys/stat.h>
  95 #include <sys/ioctl.h>
  96 #include <sys/socket.h>
  97 #include <sys/un.h>
  98 #include <sys/file.h>
  99 #include <sys/wait.h>
 100 #include <sys/time.h>
 101 #include <sys/resource.h>
 102
 103 #ifndef __linux__
 104 #ifndef RLIMIT_NOFILE
 105 #define RLIMIT_NOFILE   RLIMIT_OFILE
 106 #endif
 107 #endif
 108
 109 #include <sys/param.h>
 110 #include <sys/stat.h>
 111 #include <sys/ioctl.h>
 112 #include <sys/socket.h>
 113 #include <sys/file.h>
 114 #include <sys/wait.h>
 115 #include <sys/time.h>
 116 #include <sys/resource.h>
 117
 118 #include <netinet/in.h>
 119 #include <netinet/ip.h>
 120 #include <arpa/inet.h>
 121
 122 #include <errno.h>
 123 #include <signal.h>
 124 #include <netdb.h>
 125 #include <syslog.h>
 126 #include <stdio.h>
 127 #include <stdlib.h>
 128 #include <string.h>
 129 #include <getopt.h>
 130 #include <unistd.h>
 131 #include <stdarg.h>
 132 #include <time.h>
 133
 134 #define _PATH_INETDCONF "/etc/inetd.conf"
 135 #define _PATH_INETDPID  "/var/run/inetd.pid"
 136
 137 #define TOOMANY         40              /* don't start more than TOOMANY */
 138 #define CNT_INTVL       60              /* servers in CNT_INTVL sec. */
 139 #define RETRYTIME       (60*10)         /* retry after bind or server fail */
 140
 141 #ifndef OPEN_MAX
 142 #define OPEN_MAX        64
 143 #endif
 144
 145
 146 /* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
 147 #define FD_MARGIN       (8)
 148 static int     rlim_ofile_cur = OPEN_MAX;
 149
 150 #ifdef RLIMIT_NOFILE
 151 static struct rlimit   rlim_ofile;
 152 #endif
 153
 154 /* Check unsupporting builtin */
 155 #if defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO || \
 156         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD || \
 157         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME || \
 158         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME || \
 159         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 160 # define INETD_FEATURE_ENABLED
 161 #endif
 162
 163 static struct  servtab {
 164         char    *se_service;            /* name of service */
 165         int     se_socktype;            /* type of socket to use */
 166         int     se_family;              /* address family */
 167         char    *se_proto;              /* protocol used */
 168         short   se_wait;                /* single threaded server */
 169         short   se_checked;             /* looked at during merge */
 170         char    *se_user;               /* user name to run as */
 171         char    *se_group;              /* group name to run as */
 172 #ifdef INETD_FEATURE_ENABLED
 173         const struct  biltin *se_bi;    /* if built-in, description */
 174 #endif
 175         char    *se_server;             /* server program */
 176 #define MAXARGV 20
 177         char    *se_argv[MAXARGV+1];    /* program arguments */
 178         int     se_fd;                  /* open descriptor */
 179         union {
 180                 struct  sockaddr se_un_ctrladdr;
 181                 struct  sockaddr_in se_un_ctrladdr_in;
 182                 struct  sockaddr_un se_un_ctrladdr_un;
 183         } se_un;                        /* bound address */
 184 #define se_ctrladdr     se_un.se_un_ctrladdr
 185 #define se_ctrladdr_in  se_un.se_un_ctrladdr_in
 186 #define se_ctrladdr_un  se_un.se_un_ctrladdr_un
 187         int     se_ctrladdr_size;
 188         int     se_max;                 /* max # of instances of this service */
 189         int     se_count;               /* number started since se_time */
 190         struct  timeval se_time;        /* start of se_count */
 191         struct  servtab *se_next;
 192 } *servtab;
 193
 194 /* Length of socket listen queue. Should be per-service probably. */
 195 static int      global_queuelen = 128;
 196
 197 static int      nsock, maxsock;
 198 static fd_set   allsock;
 199 static int      timingout;
 200 static sigset_t blockmask, emptymask;
 201
 202
 203        /* Echo received data */
 204 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
 205 static void echo_stream(int, struct servtab *);
 206 static void echo_dg(int, struct servtab *);
 207 #endif
 208         /* Internet /dev/null */
 209 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
 210 static void discard_stream(int, struct servtab *);
 211 static void discard_dg(int, struct servtab *);
 212 #endif
 213         /* Return 32 bit time since 1900 */
 214 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
 215 static void machtime_stream(int, struct servtab *);
 216 static void machtime_dg(int, struct servtab *);
 217 #endif
 218         /* Return human-readable time */
 219 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
 220 static void daytime_stream(int, struct servtab *);
 221 static void daytime_dg(int, struct servtab *);
 222 #endif
 223         /* Familiar character generator */
 224 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 225 static void chargen_stream(int, struct servtab *);
 226 static void chargen_dg(int, struct servtab *);
 227 #endif
 228
 229
 230 #ifdef INETD_FEATURE_ENABLED
 231 struct biltin {
 232         const char *bi_service;         /* internally provided service name */
 233         int bi_socktype;                /* type of socket supported */
 234         short bi_fork;          /* 1 if should fork before call */
 235         short bi_wait;          /* 1 if should wait for child */
 236         void (*bi_fn)(int, struct servtab *); /* fn which performs it */
 237 };
 238
 239 static const struct biltin biltins[] = {
 240 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
 241         /* Echo received data */
 242         { "echo",               SOCK_STREAM,    1, 0,   echo_stream, },
 243         { "echo",               SOCK_DGRAM,     0, 0,   echo_dg, },
 244 #endif
 245 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
 246         /* Internet /dev/null */
 247         { "discard",    SOCK_STREAM,    1, 0,   discard_stream, },
 248         { "discard",    SOCK_DGRAM,     0, 0,   discard_dg, },
 249 #endif
 250 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
 251         /* Return 32 bit time since 1900 */
 252         { "time",               SOCK_STREAM,    0, 0,   machtime_stream, },
 253         { "time",               SOCK_DGRAM,     0, 0,   machtime_dg,     },
 254 #endif
 255 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
 256         /* Return human-readable time */
 257         { "daytime",    SOCK_STREAM,    0, 0,   daytime_stream, },
 258         { "daytime",    SOCK_DGRAM,     0, 0,   daytime_dg,     },
 259 #endif
 260 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 261         /* Familiar character generator */
 262         { "chargen",    SOCK_STREAM,    1, 0,   chargen_stream, },
 263         { "chargen",    SOCK_DGRAM,     0, 0,   chargen_dg,     },
 264 #endif
 265         { NULL, 0, 0, 0, NULL }
 266 };
 267 #endif  /* INETD_FEATURE_ENABLED */
 268
 269 static const char *CONFIG = _PATH_INETDCONF;
 270
 271 static void
 272 syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
 273         __attribute__ ((noreturn, format (printf, 2, 3)));
 274
 275 static void
 276 syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
 277 {
 278         char buf[50];
 279         va_list p;
 280
 281         va_start(p, msg);
 282         vsyslog(LOG_ERR, msg, p);
 283         if (se_socktype != SOCK_STREAM)
 284                 recv(0, buf, sizeof (buf), 0);
 285         _exit(1);
 286 }
 287
 288 static FILE *fconfig;
 289
 290 static FILE *
 291 setconfig(void)
 292 {
 293         FILE *f = fconfig;
 294
 295         if (f != NULL) {
 296                 fseek(f, 0L, L_SET);
 297         } else {
 298                 f = fconfig = fopen(CONFIG, "r");
 299                 if(f == NULL)
 300                         syslog(LOG_ERR, "%s: %m", CONFIG);
 301         }
 302         return f;
 303 }
 304
 305 static char *
 306 skip(char **cpp)
 307 {
 308         char *cp = *cpp;
 309         char *start;
 310
 311         if (*cpp == NULL)
 312                 return ((char *)0);
 313
 314 again:
 315         while (*cp == ' ' || *cp == '\t')
 316                 cp++;
 317         if (*cp == '\0') {
 318                 int c;
 319
 320                 c = getc(fconfig);
 321                 (void) ungetc(c, fconfig);
 322                 if (c == ' ' || c == '\t')
 323                         cp = bb_get_chomped_line_from_file(fconfig);
 324                         if (cp != NULL)
 325                                 goto again;
 326                 *cpp = NULL;
 327                 return NULL;
 328         }
 329         start = cp;
 330         while (*cp && *cp != ' ' && *cp != '\t')
 331                 cp++;
 332         if (*cp != '\0')
 333                 *cp++ = '\0';
 334         *cpp = cp;
 335         return (start);
 336 }
 337
 338 static char *
 339 newstr(char *cp)
 340 {
 341         cp = strdup(cp ? cp : "");
 342         if (cp)
 343                 return(cp);
 344
 345         syslog_err_and_discard_dg(SOCK_STREAM, "strdup: %m");
 346 }
 347
 348
 349 static struct servtab *
 350 getconfigent(void)
 351 {
 352         static struct servtab serv;
 353         struct servtab *sep = &serv;
 354         int argc;
 355         char *cp, *arg;
 356
 357 more:
 358         while ((cp = bb_get_chomped_line_from_file(fconfig)) && *cp == '#');
 359         if (cp == NULL)
 360                 return ((struct servtab *)0);
 361         memset((char *)sep, 0, sizeof *sep);
 362         sep->se_service = newstr(skip(&cp));
 363         arg = skip(&cp);
 364         if (arg == NULL)
 365                 goto more;
 366
 367         if (strcmp(arg, "stream") == 0)
 368                 sep->se_socktype = SOCK_STREAM;
 369         else if (strcmp(arg, "dgram") == 0)
 370                 sep->se_socktype = SOCK_DGRAM;
 371         else if (strcmp(arg, "rdm") == 0)
 372                 sep->se_socktype = SOCK_RDM;
 373         else if (strcmp(arg, "seqpacket") == 0)
 374                 sep->se_socktype = SOCK_SEQPACKET;
 375         else if (strcmp(arg, "raw") == 0)
 376                 sep->se_socktype = SOCK_RAW;
 377         else
 378                 sep->se_socktype = -1;
 379
 380         sep->se_proto = newstr(skip(&cp));
 381         if (strcmp(sep->se_proto, "unix") == 0) {
 382                 sep->se_family = AF_UNIX;
 383         } else {
 384                 sep->se_family = AF_INET;
 385                 if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
 386                         syslog(LOG_ERR, "%s: rpc services not suported",
 387                             sep->se_service);
 388                         goto more;
 389                 }
 390         }
 391         arg = skip(&cp);
 392         if (arg == NULL)
 393                 goto more;
 394         {
 395                 char    *s = strchr(arg, '.');
 396                 if (s) {
 397                         *s++ = '\0';
 398                         sep->se_max = atoi(s);
 399                 } else
 400                         sep->se_max = TOOMANY;
 401         }
 402         sep->se_wait = strcmp(arg, "wait") == 0;
 403         sep->se_user = newstr(skip(&cp));
 404         sep->se_group = strchr(sep->se_user, '.');
 405         if (sep->se_group) {
 406                 *sep->se_group++ = '\0';
 407         }
 408         sep->se_server = newstr(skip(&cp));
 409         if (strcmp(sep->se_server, "internal") == 0) {
 410 #ifdef INETD_FEATURE_ENABLED
 411                 const struct biltin *bi;
 412
 413                 for (bi = biltins; bi->bi_service; bi++)
 414                         if (bi->bi_socktype == sep->se_socktype &&
 415                             strcmp(bi->bi_service, sep->se_service) == 0)
 416                                 break;
 417                 if (bi->bi_service == 0) {
 418                         syslog(LOG_ERR, "internal service %s unknown",
 419                                 sep->se_service);
 420                         goto more;
 421                 }
 422                 sep->se_bi = bi;
 423                 sep->se_wait = bi->bi_wait;
 424 #else
 425                 syslog(LOG_ERR, "internal service %s unknown",
 426                                 sep->se_service);
 427                         goto more;
 428 #endif
 429         } else
 430 #ifdef INETD_FEATURE_ENABLED
 431         sep->se_bi = NULL
 432 #endif
 433                 ;
 434         argc = 0;
 435         for (arg = skip(&cp); cp; arg = skip(&cp)) {
 436                 if (argc < MAXARGV)
 437                         sep->se_argv[argc++] = newstr(arg);
 438         }
 439         while (argc <= MAXARGV)
 440                 sep->se_argv[argc++] = NULL;
 441         return (sep);
 442 }
 443
 444 static void
 445 freeconfig(struct servtab *cp)
 446 {
 447         int i;
 448
 449         free(cp->se_service);
 450         free(cp->se_proto);
 451         free(cp->se_user);
 452         /* Note: se_group is part of the newstr'ed se_user */
 453         free(cp->se_server);
 454         for (i = 0; i < MAXARGV; i++)
 455                 free(cp->se_argv[i]);
 456 }
 457
 458 #ifdef INETD_FEATURE_ENABLED
 459 static char **Argv;
 460 static char *LastArg;
 461
 462 static void
 463 setproctitle(char *a, int s)
 464 {
 465         size_t size;
 466         char *cp;
 467         struct sockaddr_in sn;
 468         char buf[80];
 469
 470         cp = Argv[0];
 471         size = sizeof(sn);
 472         if (getpeername(s, (struct sockaddr *)&sn, &size) == 0)
 473                 (void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sn.sin_addr));
 474         else
 475                 (void) sprintf(buf, "-%s", a);
 476         strncpy(cp, buf, LastArg - cp);
 477         cp += strlen(cp);
 478         while (cp < LastArg)
 479                 *cp++ = ' ';
 480 }
 481 #endif  /* INETD_FEATURE_ENABLED */
 482
 483 static struct servtab *
 484 enter(struct servtab *cp)
 485 {
 486         struct servtab *sep;
 487         sigset_t oldmask;
 488
 489         sep = (struct servtab *)malloc(sizeof (*sep));
 490         if (sep == NULL) {
 491                 syslog_err_and_discard_dg(SOCK_STREAM, bb_msg_memory_exhausted);
 492         }
 493         *sep = *cp;
 494         sep->se_fd = -1;
 495         sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
 496         sep->se_next = servtab;
 497         servtab = sep;
 498         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 499         return (sep);
 500 }
 501
 502 static int
 503 bump_nofile(void)
 504 {
 505 #ifdef RLIMIT_NOFILE
 506
 507 #define FD_CHUNK        32
 508
 509         struct rlimit rl;
 510
 511         if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
 512                 syslog(LOG_ERR, "getrlimit: %m");
 513                 return -1;
 514         }
 515         rl.rlim_cur = rl.rlim_max < (rl.rlim_cur + FD_CHUNK) ? rl.rlim_max : (rl.rlim_cur + FD_CHUNK);
 516         if (rl.rlim_cur <= rlim_ofile_cur) {
 517                 syslog(LOG_ERR,
 518 #if _FILE_OFFSET_BITS == 64
 519                         "bump_nofile: cannot extend file limit, max = %lld",
 520 #else
 521                         "bump_nofile: cannot extend file limit, max = %ld",
 522 #endif
 523                         rl.rlim_cur);
 524                 return -1;
 525         }
 526
 527         if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
 528                 syslog(LOG_ERR, "setrlimit: %m");
 529                 return -1;
 530         }
 531
 532         rlim_ofile_cur = rl.rlim_cur;
 533         return 0;
 534
 535 #else
 536         syslog(LOG_ERR, "bump_nofile: cannot extend file limit");
 537         return -1;
 538 #endif
 539 }
 540
 541
 542 static void
 543 setup(struct servtab *sep)
 544 {
 545         int on = 1;
 546
 547         if ((sep->se_fd = socket(sep->se_family, sep->se_socktype, 0)) < 0) {
 548                 syslog(LOG_ERR, "%s/%s: socket: %m",
 549                     sep->se_service, sep->se_proto);
 550                 return;
 551         }
 552         if (setsockopt(sep->se_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&on,
 553                             sizeof(on)) < 0)
 554                 syslog(LOG_ERR, "setsockopt (SO_REUSEADDR): %m");
 555         if (bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size) < 0) {
 556                 syslog(LOG_ERR, "%s/%s: bind: %m",
 557                     sep->se_service, sep->se_proto);
 558                 (void) close(sep->se_fd);
 559                 sep->se_fd = -1;
 560                 if (!timingout) {
 561                         timingout = 1;
 562                         alarm(RETRYTIME);
 563                 }
 564                 return;
 565         }
 566         if (sep->se_socktype == SOCK_STREAM)
 567                 listen(sep->se_fd, global_queuelen);
 568
 569         FD_SET(sep->se_fd, &allsock);
 570         nsock++;
 571         if (sep->se_fd > maxsock) {
 572                 maxsock = sep->se_fd;
 573                 if (maxsock > rlim_ofile_cur - FD_MARGIN)
 574                         bump_nofile();
 575         }
 576 }
 577
 578 static void
 579 config(int signum)
 580 {
 581         struct servtab *sep, *cp, **sepp;
 582         sigset_t oldmask;
 583         unsigned n;
 584
 585         (void)signum;
 586         if (setconfig() == NULL)
 587                 return;
 588
 589         for (sep = servtab; sep; sep = sep->se_next)
 590                 sep->se_checked = 0;
 591         while ((cp = getconfigent()) != NULL) {
 592                 for (sep = servtab; sep; sep = sep->se_next)
 593                         if (strcmp(sep->se_service, cp->se_service) == 0 &&
 594                             strcmp(sep->se_proto, cp->se_proto) == 0)
 595                                 break;
 596                 if (sep != 0) {
 597                         int i;
 598
 599 #define SWAP(type, a, b) {type c=(type)a; (type)a=(type)b; (type)b=(type)c;}
 600
 601                         sigprocmask(SIG_BLOCK, &emptymask, &oldmask);
 602                         /*
 603                          * sep->se_wait may be holding the pid of a daemon
 604                          * that we're waiting for.  If so, don't overwrite
 605                          * it unless the config file explicitly says don't
 606                          * wait.
 607                          */
 608                         if (
 609 #ifdef INETD_FEATURE_ENABLED
 610                             cp->se_bi == 0 &&
 611 #endif
 612                             (sep->se_wait == 1 || cp->se_wait == 0))
 613                                 sep->se_wait = cp->se_wait;
 614                         if (cp->se_max != sep->se_max)
 615                                 SWAP(int, cp->se_max, sep->se_max);
 616                         if (cp->se_user)
 617                                 SWAP(char *, sep->se_user, cp->se_user);
 618                         if (cp->se_group)
 619                                 SWAP(char *, sep->se_group, cp->se_group);
 620                         if (cp->se_server)
 621                                 SWAP(char *, sep->se_server, cp->se_server);
 622                         for (i = 0; i < MAXARGV; i++)
 623                                 SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
 624 #undef SWAP
 625                         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 626                         freeconfig(cp);
 627                 } else {
 628                         sep = enter(cp);
 629                 }
 630                 sep->se_checked = 1;
 631
 632                 switch (sep->se_family) {
 633                 case AF_UNIX:
 634                         if (sep->se_fd != -1)
 635                                 break;
 636                         (void)unlink(sep->se_service);
 637                         n = strlen(sep->se_service);
 638                         if (n > sizeof(sep->se_ctrladdr_un.sun_path) - 1)
 639                                 n = sizeof(sep->se_ctrladdr_un.sun_path) - 1;
 640                         strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n);
 641                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
 642                         sep->se_ctrladdr_size = n +
 643                                         sizeof sep->se_ctrladdr_un.sun_family;
 644                         setup(sep);
 645                         break;
 646                 case AF_INET:
 647                         sep->se_ctrladdr_in.sin_family = AF_INET;
 648                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
 649                         {
 650                                 u_short port = htons(atoi(sep->se_service));
 651
 652                                 if (!port) {
 653                                         struct servent *sp;
 654                                         sp = getservbyname(sep->se_service,
 655                                                                 sep->se_proto);
 656                                         if (sp == 0) {
 657                                                 syslog(LOG_ERR,
 658                                                     "%s/%s: unknown service",
 659                                                     sep->se_service, sep->se_proto);
 660                                                 continue;
 661                                         }
 662                                         port = sp->s_port;
 663                                 }
 664                                 if (port != sep->se_ctrladdr_in.sin_port) {
 665                                         sep->se_ctrladdr_in.sin_port = port;
 666                                         if (sep->se_fd != -1) {
 667                                                 FD_CLR(sep->se_fd, &allsock);
 668                                                 nsock--;
 669                                                 (void) close(sep->se_fd);
 670                                         }
 671                                         sep->se_fd = -1;
 672                                 }
 673                                 if (sep->se_fd == -1)
 674                                         setup(sep);
 675                         }
 676                 }
 677         }
 678         if (fconfig) {
 679                 (void) fclose(fconfig);
 680                 fconfig = NULL;
 681         }
 682         /*
 683          * Purge anything not looked at above.
 684          */
 685         sigprocmask(SIG_SETMASK, &blockmask, &oldmask);
 686         sepp = &servtab;
 687         while ((sep = *sepp) != NULL) {
 688                 if (sep->se_checked) {
 689                         sepp = &sep->se_next;
 690                         continue;
 691                 }
 692                 *sepp = sep->se_next;
 693                 if (sep->se_fd != -1) {
 694                         FD_CLR(sep->se_fd, &allsock);
 695                         nsock--;
 696                         (void) close(sep->se_fd);
 697                 }
 698                 if (sep->se_family == AF_UNIX)
 699                         (void)unlink(sep->se_service);
 700                 freeconfig(sep);
 701                 free((char *)sep);
 702         }
 703         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 704 }
 705
 706
 707
 708 static void
 709 reapchild(int signum)
 710 {
 711         int status;
 712         int pid;
 713         struct servtab *sep;
 714
 715         (void)signum;
 716         for (;;) {
 717                 pid = wait3(&status, WNOHANG, (struct rusage *)0);
 718                 if (pid <= 0)
 719                         break;
 720                 for (sep = servtab; sep; sep = sep->se_next)
 721                         if (sep->se_wait == pid) {
 722                                 if (WIFEXITED(status) && WEXITSTATUS(status))
 723                                         syslog(LOG_WARNING,
 724                                             "%s: exit status 0x%x",
 725                                             sep->se_server, WEXITSTATUS(status));
 726                                 else if (WIFSIGNALED(status))
 727                                         syslog(LOG_WARNING,
 728                                             "%s: exit signal 0x%x",
 729                                             sep->se_server, WTERMSIG(status));
 730                                 sep->se_wait = 1;
 731                                 FD_SET(sep->se_fd, &allsock);
 732                                 nsock++;
 733                         }
 734         }
 735 }
 736
 737 static void
 738 retry(int signum)
 739 {
 740         struct servtab *sep;
 741
 742         (void)signum;
 743         timingout = 0;
 744         for (sep = servtab; sep; sep = sep->se_next) {
 745                 if (sep->se_fd == -1) {
 746                         switch (sep->se_family) {
 747                         case AF_UNIX:
 748                         case AF_INET:
 749                                 setup(sep);
 750                                 break;
 751                         }
 752                 }
 753         }
 754 }
 755
 756 static void
 757 goaway(int signum)
 758 {
 759         struct servtab *sep;
 760
 761         (void)signum;
 762         for (sep = servtab; sep; sep = sep->se_next)
 763                 if (sep->se_fd != -1 && sep->se_family == AF_UNIX)
 764                         (void)unlink(sep->se_service);
 765         (void)unlink(_PATH_INETDPID);
 766         exit(0);
 767 }
 768
 769
 770
 771 extern int
 772 inetd_main(int argc, char *argv[])
 773 {
 774         struct servtab *sep;
 775         struct passwd *pwd;
 776         struct group *grp = NULL;
 777         struct sigaction sa;
 778         int pid;
 779         unsigned long opt;
 780         char *sq;
 781         gid_t gid;
 782
 783 #ifdef INETD_FEATURE_ENABLED
 784         int dofork;
 785         extern char **environ;
 786 #else
 787 # define dofork 1
 788 #endif
 789
 790         gid = getgid();
 791         setgroups(1, &gid);
 792
 793 #ifdef INETD_FEATURE_ENABLED
 794         Argv = argv;
 795         if (environ == 0 || *environ == 0)
 796                 environ = argv;
 797         while (*environ)
 798                 environ++;
 799         LastArg = environ[-1] + strlen(environ[-1]);
 800 #endif
 801
 802 #if defined(__uClinux__)
 803         opt = bb_getopt_ulflags(argc, argv, "q:f", &sq);
 804         if (!(opt & 2)) {
 805             daemon(0, 0);
 806             /* reexec for vfork() do continue parent */
 807             vfork_daemon_rexec(argc, argv, "-f");
 808         }
 809 #else
 810         opt = bb_getopt_ulflags(argc, argv, "q:", &sq);
 811         daemon(0, 0);
 812 #endif /* uClinux */
 813
 814         if(opt & 1) {
 815                         global_queuelen = atoi(optarg);
 816                         if (global_queuelen < 8) global_queuelen=8;
 817                 }
 818         argc -= optind;
 819         argv += optind;
 820
 821         if (argc > 0)
 822                 CONFIG = argv[0];
 823
 824         openlog(bb_applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
 825         {
 826                 FILE *fp;
 827
 828                 if ((fp = fopen(_PATH_INETDPID, "w")) != NULL) {
 829                         fprintf(fp, "%u\n", getpid());
 830                         (void)fclose(fp);
 831                 }
 832         }
 833
 834 #ifdef RLIMIT_NOFILE
 835         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
 836                 syslog(LOG_ERR, "getrlimit: %m");
 837         } else {
 838                 rlim_ofile_cur = rlim_ofile.rlim_cur;
 839                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
 840                         rlim_ofile_cur = OPEN_MAX;
 841         }
 842 #endif
 843
 844         config(0);
 845
 846         sigemptyset(&emptymask);
 847         sigemptyset(&blockmask);
 848         sigaddset(&blockmask, SIGCHLD);
 849         sigaddset(&blockmask, SIGHUP);
 850         sigaddset(&blockmask, SIGALRM);
 851
 852         memset(&sa, 0, sizeof(sa));
 853         sa.sa_mask = blockmask;
 854         sa.sa_handler = retry;
 855         sigaction(SIGALRM, &sa, NULL);
 856         sa.sa_handler = config;
 857         sigaction(SIGHUP, &sa, NULL);
 858         sa.sa_handler = reapchild;
 859         sigaction(SIGCHLD, &sa, NULL);
 860         sa.sa_handler = goaway;
 861         sigaction(SIGTERM, &sa, NULL);
 862         sa.sa_handler = goaway;
 863         sigaction(SIGINT, &sa,  NULL);
 864         sa.sa_handler = SIG_IGN;
 865         sigaction(SIGPIPE, &sa, NULL);
 866
 867         {
 868                 /* space for daemons to overwrite environment for ps */
 869 #define DUMMYSIZE       100
 870                 char dummy[DUMMYSIZE];
 871
 872                 (void)memset(dummy, 'x', DUMMYSIZE - 1);
 873                 dummy[DUMMYSIZE - 1] = '\0';
 874
 875                 (void)setenv("inetd_dummy", dummy, 1);
 876         }
 877
 878         for (;;) {
 879             int n, ctrl;
 880             fd_set readable;
 881
 882             if (nsock == 0) {
 883                 sigprocmask(SIG_BLOCK, &blockmask, NULL);
 884                 while (nsock == 0)
 885                     sigsuspend(&emptymask);
 886                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 887             }
 888             readable = allsock;
 889             if ((n = select(maxsock + 1, &readable, (fd_set *)0,
 890                 (fd_set *)0, (struct timeval *)0)) <= 0) {
 891                     if (n < 0 && errno != EINTR)
 892                         syslog(LOG_WARNING, "select: %m");
 893                     sleep(1);
 894                     continue;
 895             }
 896             for (sep = servtab; n && sep; sep = sep->se_next)
 897             if (sep->se_fd != -1 && FD_ISSET(sep->se_fd, &readable)) {
 898                 n--;
 899                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
 900                         /* Fixed AGC */
 901                         fcntl(sep->se_fd, F_SETFL, O_NDELAY);
 902                         /* --------- */
 903                         ctrl = accept(sep->se_fd, NULL, NULL);
 904                         fcntl(sep->se_fd, F_SETFL, 0);
 905                         if (ctrl < 0) {
 906                                 if (errno == EINTR || errno == EWOULDBLOCK)
 907                                         continue;
 908                                 syslog(LOG_WARNING, "accept (for %s): %m",
 909                                         sep->se_service);
 910                                 continue;
 911                         }
 912                 } else
 913                         ctrl = sep->se_fd;
 914                 sigprocmask(SIG_BLOCK, &blockmask, NULL);
 915                 pid = 0;
 916 #ifdef INETD_FEATURE_ENABLED
 917                 dofork = (sep->se_bi == 0 || sep->se_bi->bi_fork);
 918 #endif
 919                 if (dofork) {
 920                         if (sep->se_count++ == 0)
 921                             (void)gettimeofday(&sep->se_time,
 922                                 (struct timezone *)0);
 923                         else if (sep->se_count >= sep->se_max) {
 924                                 struct timeval now;
 925
 926                                 (void)gettimeofday(&now, (struct timezone *)0);
 927                                 if (now.tv_sec - sep->se_time.tv_sec >
 928                                     CNT_INTVL) {
 929                                         sep->se_time = now;
 930                                         sep->se_count = 1;
 931                                 } else {
 932                                         syslog(LOG_ERR,
 933                         "%s/%s server failing (looping), service terminated",
 934                                             sep->se_service, sep->se_proto);
 935                                         FD_CLR(sep->se_fd, &allsock);
 936                                         (void) close(sep->se_fd);
 937                                         sep->se_fd = -1;
 938                                         sep->se_count = 0;
 939                                         nsock--;
 940                                         sigprocmask(SIG_SETMASK, &emptymask,
 941                                                     NULL);
 942                                         if (!timingout) {
 943                                                 timingout = 1;
 944                                                 alarm(RETRYTIME);
 945                                         }
 946                                         continue;
 947                                 }
 948                         }
 949                         pid = fork();
 950                 }
 951                 if (pid < 0) {
 952                         syslog(LOG_ERR, "fork: %m");
 953                         if (sep->se_socktype == SOCK_STREAM)
 954                                 close(ctrl);
 955                         sigprocmask(SIG_SETMASK, &emptymask, NULL);
 956                         sleep(1);
 957                         continue;
 958                 }
 959                 if (pid && sep->se_wait) {
 960                         sep->se_wait = pid;
 961                         FD_CLR(sep->se_fd, &allsock);
 962                         nsock--;
 963                 }
 964                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 965                 if (pid == 0) {
 966 #ifdef INETD_FEATURE_ENABLED
 967                         if (sep->se_bi)
 968                                 (*sep->se_bi->bi_fn)(ctrl, sep);
 969                         else
 970 #endif
 971                               {
 972                                 if ((pwd = getpwnam(sep->se_user)) == NULL) {
 973                                         syslog_err_and_discard_dg(
 974                                                 sep->se_socktype,
 975                                                 "getpwnam: %s: No such user",
 976                                                 sep->se_user);
 977                                 }
 978                                 if (sep->se_group &&
 979                                     (grp = getgrnam(sep->se_group)) == NULL) {
 980                                         syslog_err_and_discard_dg(
 981                                                 sep->se_socktype,
 982                                                 "getgrnam: %s: No such group",
 983                                                 sep->se_group);
 984                                 }
 985                                 /*
 986                                  * Ok. There are four cases here:
 987                                  *   1. nonroot user, no group specified
 988                                  *   2. nonroot user, some group specified
 989                                  *   3. root user, no group specified
 990                                  *   4. root user, some group specified
 991                                  * In cases 2 and 4 we setgid to the specified
 992                                  * group. In cases 1 and 2 we run initgroups
 993                                  * to run with the groups of the given user.
 994                                  * In case 4 we do setgroups to run with the
 995                                  * given group. In case 3 we do nothing.
 996                                  */
 997                                 if (pwd->pw_uid) {
 998                                         if (sep->se_group)
 999                                                 pwd->pw_gid = grp->gr_gid;
1000                                         setgid((gid_t)pwd->pw_gid);
1001                                         initgroups(pwd->pw_name, pwd->pw_gid);
1002                                         setuid((uid_t)pwd->pw_uid);
1003                                 } else if (sep->se_group) {
1004                                         setgid((gid_t)grp->gr_gid);
1005                                         setgroups(1, &grp->gr_gid);
1006                                 }
1007                                 dup2(ctrl, 0);
1008                                 close(ctrl);
1009                                 dup2(0, 1);
1010                                 dup2(0, 2);
1011 #ifdef RLIMIT_NOFILE
1012                                 if (rlim_ofile.rlim_cur != rlim_ofile_cur) {
1013                                         if (setrlimit(RLIMIT_NOFILE,
1014                                                         &rlim_ofile) < 0)
1015                                                 syslog(LOG_ERR,"setrlimit: %m");
1016                                 }
1017 #endif
1018                                 for (ctrl = rlim_ofile_cur-1; --ctrl > 2; )
1019                                         (void)close(ctrl);
1020
1021                                 memset(&sa, 0, sizeof(sa));
1022                                 sa.sa_handler = SIG_DFL;
1023                                 sigaction(SIGPIPE, &sa, NULL);
1024
1025                                 execv(sep->se_server, sep->se_argv);
1026                                 syslog_err_and_discard_dg(sep->se_socktype,
1027                                         "execv %s: %m", sep->se_server);
1028                         }
1029                 }
1030                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1031                         close(ctrl);
1032             }
1033         }
1034 }
1035
1036
1037 /*
1038  * Internet services provided internally by inetd:
1039  */
1040 #define BUFSIZE 4096
1041
1042 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
1043 /* Echo service -- echo data back */
1044 static void
1045 echo_stream(int s, struct servtab *sep)
1046 {
1047         char buffer[BUFSIZE];
1048         int i;
1049
1050         setproctitle(sep->se_service, s);
1051         while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
1052             write(s, buffer, i) > 0)
1053                 ;
1054         exit(0);
1055 }
1056
1057 /* Echo service -- echo data back */
1058 static void
1059 echo_dg(int s, struct servtab *sep)
1060 {
1061         char buffer[BUFSIZE];
1062         int i;
1063         size_t size;
1064         struct sockaddr sa;
1065
1066         (void)sep;
1067
1068         size = sizeof(sa);
1069         if ((i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size)) < 0)
1070                 return;
1071         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1072 }
1073 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO */
1074
1075
1076 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
1077 /* Discard service -- ignore data */
1078 static void
1079 discard_stream(int s, struct servtab *sep)
1080 {
1081         char buffer[BUFSIZE];
1082
1083         setproctitle(sep->se_service, s);
1084         while ((errno = 0, read(s, buffer, sizeof(buffer)) > 0) ||
1085                         errno == EINTR)
1086                 ;
1087         exit(0);
1088 }
1089
1090 /* Discard service -- ignore data */
1091 static void
1092 discard_dg(int s, struct servtab *sep)
1093 {
1094         char buffer[BUFSIZE];
1095         (void)sep;
1096         read(s, buffer, sizeof(buffer));
1097 }
1098 #endif  /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD */
1099
1100
1101 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
1102 #include <ctype.h>
1103 #define LINESIZ 72
1104 static char ring[128];
1105 static char *endring;
1106
1107 static void
1108 initring(void)
1109 {
1110         int i;
1111
1112         endring = ring;
1113
1114         for (i = 0; i <= 128; ++i)
1115                 if (isprint(i))
1116                         *endring++ = i;
1117 }
1118
1119 /* Character generator */
1120 static void
1121 chargen_stream(int s, struct servtab *sep)
1122 {
1123         char *rs;
1124         int len;
1125         char text[LINESIZ+2];
1126
1127         setproctitle(sep->se_service, s);
1128
1129         if (!endring) {
1130                 initring();
1131                 rs = ring;
1132         }
1133
1134         text[LINESIZ] = '\r';
1135         text[LINESIZ + 1] = '\n';
1136         for (rs = ring;;) {
1137                 if ((len = endring - rs) >= LINESIZ)
1138                         memcpy(rs, text, LINESIZ);
1139                 else {
1140                         memcpy(rs, text, len);
1141                         memcpy(ring, text + len, LINESIZ - len);
1142                 }
1143                 if (++rs == endring)
1144                         rs = ring;
1145                 if (write(s, text, sizeof(text)) != sizeof(text))
1146                         break;
1147         }
1148         exit(0);
1149 }
1150
1151 /* Character generator */
1152 static void
1153 chargen_dg(int s, struct servtab *sep)
1154 {
1155         struct sockaddr sa;
1156         static char *rs;
1157         size_t len, size;
1158         char text[LINESIZ+2];
1159
1160         (void)sep;
1161
1162         if (endring == 0) {
1163                 initring();
1164                 rs = ring;
1165         }
1166
1167         size = sizeof(sa);
1168         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1169                 return;
1170
1171         if ((len = endring - rs) >= LINESIZ)
1172                 memcpy(rs, text, LINESIZ);
1173         else {
1174                 memcpy(rs, text, len);
1175                 memcpy(ring, text + len, LINESIZ - len);
1176         }
1177         if (++rs == endring)
1178                 rs = ring;
1179         text[LINESIZ] = '\r';
1180         text[LINESIZ + 1] = '\n';
1181         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1182 }
1183 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN */
1184
1185
1186 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
1187 /*
1188  * Return a machine readable date and time, in the form of the
1189  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1190  * returns the number of seconds since midnight, Jan 1, 1970,
1191  * we must add 2208988800 seconds to this figure to make up for
1192  * some seventy years Bell Labs was asleep.
1193  */
1194
1195 static long
1196 machtime(void)
1197 {
1198         struct timeval tv;
1199
1200         if (gettimeofday(&tv, (struct timezone *)0) < 0) {
1201                 fprintf(stderr, "Unable to get time of day\n");
1202                 return (0L);
1203         }
1204         return (htonl((long)tv.tv_sec + 2208988800UL));
1205 }
1206
1207 static void
1208 machtime_stream(int s, struct servtab *sep)
1209 {
1210         long result;
1211         (void)sep;
1212
1213         result = machtime();
1214         write(s, (char *) &result, sizeof(result));
1215 }
1216
1217 static void
1218 machtime_dg(int s, struct servtab *sep)
1219 {
1220         long result;
1221         struct sockaddr sa;
1222         size_t size;
1223         (void)sep;
1224
1225         size = sizeof(sa);
1226         if (recvfrom(s, (char *)&result, sizeof(result), 0, &sa, &size) < 0)
1227                 return;
1228         result = machtime();
1229         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1230 }
1231 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME */
1232
1233
1234 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
1235 /* Return human-readable time of day */
1236 static int
1237 human_readable_time_sprintf(char *buffer)
1238 {
1239         time_t clocc = time(NULL);
1240
1241         return sprintf(buffer, "%.24s\r\n", ctime(&clocc));
1242 }
1243
1244 static void
1245 daytime_stream(int s, struct servtab *sep)
1246 {
1247         char buffer[256];
1248         size_t st = human_readable_time_sprintf(buffer);
1249
1250         (void)sep;
1251
1252         write(s, buffer, st);
1253 }
1254
1255 /* Return human-readable time of day */
1256 static void
1257 daytime_dg(int s, struct servtab *sep)
1258 {
1259         char buffer[256];
1260         struct sockaddr sa;
1261         size_t size;
1262
1263         (void)sep;
1264
1265         size = sizeof(sa);
1266         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1267                 return;
1268         size = human_readable_time_sprintf(buffer);
1269         sendto(s, buffer, size, 0, &sa, sizeof(sa));
1270 }
1271 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME */