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 #ifndef MIN
 138 #define MIN(a, b)       ((a) < (b) ? (a) : (b))
 139 #endif
 140
 141 #define TOOMANY         40              /* don't start more than TOOMANY */
 142 #define CNT_INTVL       60              /* servers in CNT_INTVL sec. */
 143 #define RETRYTIME       (60*10)         /* retry after bind or server fail */
 144
 145 #ifndef OPEN_MAX
 146 #define OPEN_MAX        64
 147 #endif
 148
 149
 150 /* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
 151 #define FD_MARGIN       (8)
 152 static int     rlim_ofile_cur = OPEN_MAX;
 153
 154 #ifdef RLIMIT_NOFILE
 155 static struct rlimit   rlim_ofile;
 156 #endif
 157
 158 #define INETD_UNSUPPORT_BILTIN 1
 159
 160 /* Check unsupporting builtin */
 161 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
 162 #undef INETD_UNSUPPORT_BILTIN
 163 #endif
 164 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
 165 #undef INETD_UNSUPPORT_BILTIN
 166 #endif
 167 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
 168 #undef INETD_UNSUPPORT_BILTIN
 169 #endif
 170 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
 171 #undef INETD_UNSUPPORT_BILTIN
 172 #endif
 173 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 174 #undef INETD_UNSUPPORT_BILTIN
 175 #endif
 176
 177 static struct  servtab {
 178         char    *se_service;            /* name of service */
 179         int     se_socktype;            /* type of socket to use */
 180         int     se_family;              /* address family */
 181         char    *se_proto;              /* protocol used */
 182         short   se_wait;                /* single threaded server */
 183         short   se_checked;             /* looked at during merge */
 184         char    *se_user;               /* user name to run as */
 185         char    *se_group;              /* group name to run as */
 186 #ifndef INETD_UNSUPPORT_BILTIN
 187         const struct  biltin *se_bi;    /* if built-in, description */
 188 #endif
 189         char    *se_server;             /* server program */
 190 #define MAXARGV 20
 191         char    *se_argv[MAXARGV+1];    /* program arguments */
 192         int     se_fd;                  /* open descriptor */
 193         union {
 194                 struct  sockaddr se_un_ctrladdr;
 195                 struct  sockaddr_in se_un_ctrladdr_in;
 196                 struct  sockaddr_un se_un_ctrladdr_un;
 197         } se_un;                        /* bound address */
 198 #define se_ctrladdr     se_un.se_un_ctrladdr
 199 #define se_ctrladdr_in  se_un.se_un_ctrladdr_in
 200 #define se_ctrladdr_un  se_un.se_un_ctrladdr_un
 201         int     se_ctrladdr_size;
 202         int     se_max;                 /* max # of instances of this service */
 203         int     se_count;               /* number started since se_time */
 204         struct  timeval se_time;        /* start of se_count */
 205         struct  servtab *se_next;
 206 } *servtab;
 207
 208 /* Length of socket listen queue. Should be per-service probably. */
 209 static int      global_queuelen = 128;
 210
 211 static int      nsock, maxsock;
 212 static fd_set   allsock;
 213 static int      timingout;
 214 static sigset_t blockmask, emptymask;
 215
 216
 217        /* Echo received data */
 218 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
 219 static void echo_stream(int, struct servtab *);
 220 static void echo_dg(int, struct servtab *);
 221 #endif
 222         /* Internet /dev/null */
 223 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
 224 static void discard_stream(int, struct servtab *);
 225 static void discard_dg(int, struct servtab *);
 226 #endif
 227         /* Return 32 bit time since 1900 */
 228 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
 229 static void machtime_stream(int, struct servtab *);
 230 static void machtime_dg(int, struct servtab *);
 231 #endif
 232         /* Return human-readable time */
 233 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
 234 static void daytime_stream(int, struct servtab *);
 235 static void daytime_dg(int, struct servtab *);
 236 #endif
 237         /* Familiar character generator */
 238 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 239 static void chargen_stream(int, struct servtab *);
 240 static void chargen_dg(int, struct servtab *);
 241 #endif
 242
 243 #ifndef INETD_UNSUPPORT_BILTIN
 244 struct biltin {
 245         const char *bi_service;         /* internally provided service name */
 246         int bi_socktype;                /* type of socket supported */
 247         short bi_fork;          /* 1 if should fork before call */
 248         short bi_wait;          /* 1 if should wait for child */
 249         void (*bi_fn)(int, struct servtab *); /* fn which performs it */
 250 };
 251
 252 static const struct biltin biltins[] = {
 253 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
 254         /* Echo received data */
 255         { "echo",               SOCK_STREAM,    1, 0,   echo_stream, },
 256         { "echo",               SOCK_DGRAM,     0, 0,   echo_dg, },
 257 #endif
 258 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
 259         /* Internet /dev/null */
 260         { "discard",    SOCK_STREAM,    1, 0,   discard_stream, },
 261         { "discard",    SOCK_DGRAM,     0, 0,   discard_dg, },
 262 #endif
 263 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
 264         /* Return 32 bit time since 1900 */
 265         { "time",               SOCK_STREAM,    0, 0,   machtime_stream, },
 266         { "time",               SOCK_DGRAM,     0, 0,   machtime_dg,     },
 267 #endif
 268 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
 269         /* Return human-readable time */
 270         { "daytime",    SOCK_STREAM,    0, 0,   daytime_stream, },
 271         { "daytime",    SOCK_DGRAM,     0, 0,   daytime_dg,     },
 272 #endif
 273 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 274         /* Familiar character generator */
 275         { "chargen",    SOCK_STREAM,    1, 0,   chargen_stream, },
 276         { "chargen",    SOCK_DGRAM,     0, 0,   chargen_dg,     },
 277 #endif
 278         { NULL, 0, 0, 0, NULL }
 279 };
 280 #endif  /* INETD_UNSUPPORT_BILTIN */
 281
 282 #define NUMINT  (sizeof(intab) / sizeof(struct inent))
 283 static const char *CONFIG = _PATH_INETDCONF;
 284
 285 #define BCOPY(s, d, z) memcpy(d, s, z)
 286
 287 static void
 288 syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
 289         __attribute__ ((noreturn, format (printf, 2, 3)));
 290
 291 static void
 292 syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
 293 {
 294         char buf[50];
 295         va_list p;
 296
 297         va_start(p, msg);
 298         vsyslog(LOG_ERR, msg, p);
 299         if (se_socktype != SOCK_STREAM)
 300                 recv(0, buf, sizeof (buf), 0);
 301         _exit(1);
 302 }
 303
 304 static FILE *fconfig;
 305 static char line[256];
 306
 307 static FILE *
 308 setconfig(void)
 309 {
 310         FILE *f = fconfig;
 311
 312         if (f != NULL) {
 313                 fseek(f, 0L, L_SET);
 314         } else {
 315                 f = fconfig = fopen(CONFIG, "r");
 316                 if(f == NULL)
 317                         syslog(LOG_ERR, "%s: %m", CONFIG);
 318         }
 319         return f;
 320 }
 321
 322 static char *
 323 nextline(void)
 324 {
 325         char *cp;
 326         FILE *fd = fconfig;
 327
 328         if (fgets(line, sizeof (line), fd) == NULL)
 329                 return ((char *)0);
 330         cp = strchr(line, '\n');
 331         if (cp)
 332                 *cp = '\0';
 333         return (line);
 334 }
 335
 336 static char *
 337 skip(char **cpp)
 338 {
 339         char *cp = *cpp;
 340         char *start;
 341
 342         if (*cpp == NULL)
 343                 return ((char *)0);
 344
 345 again:
 346         while (*cp == ' ' || *cp == '\t')
 347                 cp++;
 348         if (*cp == '\0') {
 349                 int c;
 350
 351                 c = getc(fconfig);
 352                 (void) ungetc(c, fconfig);
 353                 if (c == ' ' || c == '\t')
 354                         if ((cp = nextline()) != NULL)
 355                                 goto again;
 356                 *cpp = NULL;
 357                 return NULL;
 358         }
 359         start = cp;
 360         while (*cp && *cp != ' ' && *cp != '\t')
 361                 cp++;
 362         if (*cp != '\0')
 363                 *cp++ = '\0';
 364         *cpp = cp;
 365         return (start);
 366 }
 367
 368 static char *
 369 newstr(char *cp)
 370 {
 371         cp = strdup(cp ? cp : "");
 372         if (cp)
 373                 return(cp);
 374
 375         syslog_err_and_discard_dg(SOCK_STREAM, "strdup: %m");
 376 }
 377
 378
 379 static struct servtab *
 380 getconfigent(void)
 381 {
 382         static struct servtab serv;
 383         struct servtab *sep = &serv;
 384         int argc;
 385         char *cp, *arg;
 386
 387 more:
 388         while ((cp = nextline()) && *cp == '#')
 389                 ;
 390         if (cp == NULL)
 391                 return ((struct servtab *)0);
 392         memset((char *)sep, 0, sizeof *sep);
 393         sep->se_service = newstr(skip(&cp));
 394         arg = skip(&cp);
 395         if (arg == NULL)
 396                 goto more;
 397
 398         if (strcmp(arg, "stream") == 0)
 399                 sep->se_socktype = SOCK_STREAM;
 400         else if (strcmp(arg, "dgram") == 0)
 401                 sep->se_socktype = SOCK_DGRAM;
 402         else if (strcmp(arg, "rdm") == 0)
 403                 sep->se_socktype = SOCK_RDM;
 404         else if (strcmp(arg, "seqpacket") == 0)
 405                 sep->se_socktype = SOCK_SEQPACKET;
 406         else if (strcmp(arg, "raw") == 0)
 407                 sep->se_socktype = SOCK_RAW;
 408         else
 409                 sep->se_socktype = -1;
 410
 411         sep->se_proto = newstr(skip(&cp));
 412         if (strcmp(sep->se_proto, "unix") == 0) {
 413                 sep->se_family = AF_UNIX;
 414         } else {
 415                 sep->se_family = AF_INET;
 416                 if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
 417                         syslog(LOG_ERR, "%s: rpc services not suported",
 418                             sep->se_service);
 419                         goto more;
 420                 }
 421         }
 422         arg = skip(&cp);
 423         if (arg == NULL)
 424                 goto more;
 425         {
 426                 char    *s = strchr(arg, '.');
 427                 if (s) {
 428                         *s++ = '\0';
 429                         sep->se_max = atoi(s);
 430                 } else
 431                         sep->se_max = TOOMANY;
 432         }
 433         sep->se_wait = strcmp(arg, "wait") == 0;
 434         sep->se_user = newstr(skip(&cp));
 435         sep->se_group = strchr(sep->se_user, '.');
 436         if (sep->se_group) {
 437                 *sep->se_group++ = '\0';
 438         }
 439         sep->se_server = newstr(skip(&cp));
 440         if (strcmp(sep->se_server, "internal") == 0) {
 441 #ifndef INETD_UNSUPPORT_BILTIN
 442                 const struct biltin *bi;
 443
 444                 for (bi = biltins; bi->bi_service; bi++)
 445                         if (bi->bi_socktype == sep->se_socktype &&
 446                             strcmp(bi->bi_service, sep->se_service) == 0)
 447                                 break;
 448                 if (bi->bi_service == 0) {
 449                         syslog(LOG_ERR, "internal service %s unknown",
 450                                 sep->se_service);
 451                         goto more;
 452                 }
 453                 sep->se_bi = bi;
 454                 sep->se_wait = bi->bi_wait;
 455 #else
 456                 syslog(LOG_ERR, "internal service %s unknown",
 457                                 sep->se_service);
 458                         goto more;
 459 #endif
 460         } else
 461 #ifndef INETD_UNSUPPORT_BILTIN
 462                 sep->se_bi = NULL
 463 #endif
 464                 ;
 465         argc = 0;
 466         for (arg = skip(&cp); cp; arg = skip(&cp)) {
 467                 if (argc < MAXARGV)
 468                         sep->se_argv[argc++] = newstr(arg);
 469         }
 470         while (argc <= MAXARGV)
 471                 sep->se_argv[argc++] = NULL;
 472         return (sep);
 473 }
 474
 475 static void
 476 freeconfig(struct servtab *cp)
 477 {
 478         int i;
 479
 480         free(cp->se_service);
 481         free(cp->se_proto);
 482         free(cp->se_user);
 483         /* Note: se_group is part of the newstr'ed se_user */
 484         free(cp->se_server);
 485         for (i = 0; i < MAXARGV; i++)
 486                 free(cp->se_argv[i]);
 487 }
 488
 489 #ifndef INETD_UNSUPPORT_BILTIN
 490 static char **Argv;
 491 static char *LastArg;
 492
 493 static void
 494 setproctitle(char *a, int s)
 495 {
 496         size_t size;
 497         char *cp;
 498         struct sockaddr_in sn;
 499         char buf[80];
 500
 501         cp = Argv[0];
 502         size = sizeof(sn);
 503         if (getpeername(s, (struct sockaddr *)&sn, &size) == 0)
 504                 (void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sn.sin_addr));
 505         else
 506                 (void) sprintf(buf, "-%s", a);
 507         strncpy(cp, buf, LastArg - cp);
 508         cp += strlen(cp);
 509         while (cp < LastArg)
 510                 *cp++ = ' ';
 511 }
 512 #endif  /* INETD_UNSUPPORT_BILTIN */
 513
 514 static struct servtab *
 515 enter(struct servtab *cp)
 516 {
 517         struct servtab *sep;
 518         sigset_t oldmask;
 519
 520         sep = (struct servtab *)malloc(sizeof (*sep));
 521         if (sep == NULL) {
 522                 syslog_err_and_discard_dg(SOCK_STREAM, bb_msg_memory_exhausted);
 523         }
 524         *sep = *cp;
 525         sep->se_fd = -1;
 526         sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
 527         sep->se_next = servtab;
 528         servtab = sep;
 529         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 530         return (sep);
 531 }
 532
 533 static int
 534 bump_nofile(void)
 535 {
 536 #ifdef RLIMIT_NOFILE
 537
 538 #define FD_CHUNK        32
 539
 540         struct rlimit rl;
 541
 542         if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
 543                 syslog(LOG_ERR, "getrlimit: %m");
 544                 return -1;
 545         }
 546         rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
 547         if (rl.rlim_cur <= rlim_ofile_cur) {
 548                 syslog(LOG_ERR,
 549 #if _FILE_OFFSET_BITS == 64
 550                         "bump_nofile: cannot extend file limit, max = %lld",
 551 #else
 552                         "bump_nofile: cannot extend file limit, max = %ld",
 553 #endif
 554                         rl.rlim_cur);
 555                 return -1;
 556         }
 557
 558         if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
 559                 syslog(LOG_ERR, "setrlimit: %m");
 560                 return -1;
 561         }
 562
 563         rlim_ofile_cur = rl.rlim_cur;
 564         return 0;
 565
 566 #else
 567         syslog(LOG_ERR, "bump_nofile: cannot extend file limit");
 568         return -1;
 569 #endif
 570 }
 571
 572
 573 static void
 574 setup(struct servtab *sep)
 575 {
 576         int on = 1;
 577
 578         if ((sep->se_fd = socket(sep->se_family, sep->se_socktype, 0)) < 0) {
 579                 syslog(LOG_ERR, "%s/%s: socket: %m",
 580                     sep->se_service, sep->se_proto);
 581                 return;
 582         }
 583         if (setsockopt(sep->se_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&on,
 584                             sizeof(on)) < 0)
 585                 syslog(LOG_ERR, "setsockopt (SO_REUSEADDR): %m");
 586         if (bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size) < 0) {
 587                 syslog(LOG_ERR, "%s/%s: bind: %m",
 588                     sep->se_service, sep->se_proto);
 589                 (void) close(sep->se_fd);
 590                 sep->se_fd = -1;
 591                 if (!timingout) {
 592                         timingout = 1;
 593                         alarm(RETRYTIME);
 594                 }
 595                 return;
 596         }
 597         if (sep->se_socktype == SOCK_STREAM)
 598                 listen(sep->se_fd, global_queuelen);
 599
 600         FD_SET(sep->se_fd, &allsock);
 601         nsock++;
 602         if (sep->se_fd > maxsock) {
 603                 maxsock = sep->se_fd;
 604                 if (maxsock > rlim_ofile_cur - FD_MARGIN)
 605                         bump_nofile();
 606         }
 607 }
 608
 609 static void
 610 config(int signum)
 611 {
 612         struct servtab *sep, *cp, **sepp;
 613         sigset_t oldmask;
 614         unsigned n;
 615
 616         (void)signum;
 617         if (setconfig() == NULL)
 618                 return;
 619
 620         for (sep = servtab; sep; sep = sep->se_next)
 621                 sep->se_checked = 0;
 622         while ((cp = getconfigent()) != NULL) {
 623                 for (sep = servtab; sep; sep = sep->se_next)
 624                         if (strcmp(sep->se_service, cp->se_service) == 0 &&
 625                             strcmp(sep->se_proto, cp->se_proto) == 0)
 626                                 break;
 627                 if (sep != 0) {
 628                         int i;
 629
 630 #define SWAP(type, a, b) {type c=(type)a; (type)a=(type)b; (type)b=(type)c;}
 631
 632                         sigprocmask(SIG_BLOCK, &emptymask, &oldmask);
 633                         /*
 634                          * sep->se_wait may be holding the pid of a daemon
 635                          * that we're waiting for.  If so, don't overwrite
 636                          * it unless the config file explicitly says don't
 637                          * wait.
 638                          */
 639                         if (
 640 #ifndef INETD_UNSUPPORT_BILTIN
 641                             cp->se_bi == 0 &&
 642 #endif
 643                             (sep->se_wait == 1 || cp->se_wait == 0))
 644                                 sep->se_wait = cp->se_wait;
 645                         if (cp->se_max != sep->se_max)
 646                                 SWAP(int, cp->se_max, sep->se_max);
 647                         if (cp->se_user)
 648                                 SWAP(char *, sep->se_user, cp->se_user);
 649                         if (cp->se_group)
 650                                 SWAP(char *, sep->se_group, cp->se_group);
 651                         if (cp->se_server)
 652                                 SWAP(char *, sep->se_server, cp->se_server);
 653                         for (i = 0; i < MAXARGV; i++)
 654                                 SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
 655 #undef SWAP
 656                         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 657                         freeconfig(cp);
 658                 } else {
 659                         sep = enter(cp);
 660                 }
 661                 sep->se_checked = 1;
 662
 663                 switch (sep->se_family) {
 664                 case AF_UNIX:
 665                         if (sep->se_fd != -1)
 666                                 break;
 667                         (void)unlink(sep->se_service);
 668                         n = strlen(sep->se_service);
 669                         if (n > sizeof(sep->se_ctrladdr_un.sun_path) - 1)
 670                                 n = sizeof(sep->se_ctrladdr_un.sun_path) - 1;
 671                         strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n);
 672                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
 673                         sep->se_ctrladdr_size = n +
 674                                         sizeof sep->se_ctrladdr_un.sun_family;
 675                         setup(sep);
 676                         break;
 677                 case AF_INET:
 678                         sep->se_ctrladdr_in.sin_family = AF_INET;
 679                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
 680                         {
 681                                 u_short port = htons(atoi(sep->se_service));
 682
 683                                 if (!port) {
 684                                         struct servent *sp;
 685                                         sp = getservbyname(sep->se_service,
 686                                                                 sep->se_proto);
 687                                         if (sp == 0) {
 688                                                 syslog(LOG_ERR,
 689                                                     "%s/%s: unknown service",
 690                                                     sep->se_service, sep->se_proto);
 691                                                 continue;
 692                                         }
 693                                         port = sp->s_port;
 694                                 }
 695                                 if (port != sep->se_ctrladdr_in.sin_port) {
 696                                         sep->se_ctrladdr_in.sin_port = port;
 697                                         if (sep->se_fd != -1) {
 698                                                 FD_CLR(sep->se_fd, &allsock);
 699                                                 nsock--;
 700                                                 (void) close(sep->se_fd);
 701                                         }
 702                                         sep->se_fd = -1;
 703                                 }
 704                                 if (sep->se_fd == -1)
 705                                         setup(sep);
 706                         }
 707                 }
 708         }
 709         if (fconfig) {
 710                 (void) fclose(fconfig);
 711                 fconfig = NULL;
 712         }
 713         /*
 714          * Purge anything not looked at above.
 715          */
 716         sigprocmask(SIG_SETMASK, &blockmask, &oldmask);
 717         sepp = &servtab;
 718         while ((sep = *sepp) != NULL) {
 719                 if (sep->se_checked) {
 720                         sepp = &sep->se_next;
 721                         continue;
 722                 }
 723                 *sepp = sep->se_next;
 724                 if (sep->se_fd != -1) {
 725                         FD_CLR(sep->se_fd, &allsock);
 726                         nsock--;
 727                         (void) close(sep->se_fd);
 728                 }
 729                 if (sep->se_family == AF_UNIX)
 730                         (void)unlink(sep->se_service);
 731                 freeconfig(sep);
 732                 free((char *)sep);
 733         }
 734         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 735 }
 736
 737
 738
 739 static void
 740 reapchild(int signum)
 741 {
 742         int status;
 743         int pid;
 744         struct servtab *sep;
 745
 746         (void)signum;
 747         for (;;) {
 748                 pid = wait3(&status, WNOHANG, (struct rusage *)0);
 749                 if (pid <= 0)
 750                         break;
 751                 for (sep = servtab; sep; sep = sep->se_next)
 752                         if (sep->se_wait == pid) {
 753                                 if (WIFEXITED(status) && WEXITSTATUS(status))
 754                                         syslog(LOG_WARNING,
 755                                             "%s: exit status 0x%x",
 756                                             sep->se_server, WEXITSTATUS(status));
 757                                 else if (WIFSIGNALED(status))
 758                                         syslog(LOG_WARNING,
 759                                             "%s: exit signal 0x%x",
 760                                             sep->se_server, WTERMSIG(status));
 761                                 sep->se_wait = 1;
 762                                 FD_SET(sep->se_fd, &allsock);
 763                                 nsock++;
 764                         }
 765         }
 766 }
 767
 768 static void
 769 retry(int signum)
 770 {
 771         struct servtab *sep;
 772
 773         (void)signum;
 774         timingout = 0;
 775         for (sep = servtab; sep; sep = sep->se_next) {
 776                 if (sep->se_fd == -1) {
 777                         switch (sep->se_family) {
 778                         case AF_UNIX:
 779                         case AF_INET:
 780                                 setup(sep);
 781                                 break;
 782                         }
 783                 }
 784         }
 785 }
 786
 787 static void
 788 goaway(int signum)
 789 {
 790         struct servtab *sep;
 791
 792         (void)signum;
 793         for (sep = servtab; sep; sep = sep->se_next)
 794                 if (sep->se_fd != -1 && sep->se_family == AF_UNIX)
 795                         (void)unlink(sep->se_service);
 796         (void)unlink(_PATH_INETDPID);
 797         exit(0);
 798 }
 799
 800
 801
 802 extern int
 803 inetd_main(int argc, char *argv[])
 804 {
 805         struct servtab *sep;
 806         struct passwd *pwd;
 807         struct group *grp = NULL;
 808         struct sigaction sa;
 809         int pid;
 810         unsigned long opt;
 811         char *sq;
 812         gid_t gid;
 813
 814 #ifdef INETD_UNSUPPORT_BILTIN
 815 # define dofork 1
 816 #else
 817         int dofork;
 818         extern char **environ;
 819 #endif
 820
 821         gid = getgid();
 822         setgroups(1, &gid);
 823
 824 #ifndef INETD_UNSUPPORT_BILTIN
 825         Argv = argv;
 826         if (environ == 0 || *environ == 0)
 827                 environ = argv;
 828         while (*environ)
 829                 environ++;
 830         LastArg = environ[-1] + strlen(environ[-1]);
 831 #endif
 832
 833 #if defined(__uClinux__)
 834         opt = bb_getopt_ulflags(argc, argv, "q:f", &sq);
 835         if (!(opt & 4)) {
 836             daemon(0, 0);
 837             /* reexec for vfork() do continue parent */
 838             vfork_daemon_rexec(argc, argv, "-f");
 839         }
 840 #else
 841         opt = bb_getopt_ulflags(ac, av, "q:", &sq);
 842         daemon(0, 0);
 843 #endif /* uClinux */
 844
 845         if(opt & 1) {
 846                         global_queuelen = atoi(optarg);
 847                         if (global_queuelen < 8) global_queuelen=8;
 848                 }
 849         argc -= optind;
 850         argv += optind;
 851
 852         if (argc > 0)
 853                 CONFIG = argv[0];
 854
 855         openlog(bb_applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
 856         {
 857                 FILE *fp;
 858
 859                 if ((fp = fopen(_PATH_INETDPID, "w")) != NULL) {
 860                         fprintf(fp, "%u\n", getpid());
 861                         (void)fclose(fp);
 862                 }
 863         }
 864
 865 #ifdef RLIMIT_NOFILE
 866         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
 867                 syslog(LOG_ERR, "getrlimit: %m");
 868         } else {
 869                 rlim_ofile_cur = rlim_ofile.rlim_cur;
 870                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
 871                         rlim_ofile_cur = OPEN_MAX;
 872         }
 873 #endif
 874
 875         config(0);
 876
 877         sigemptyset(&emptymask);
 878         sigemptyset(&blockmask);
 879         sigaddset(&blockmask, SIGCHLD);
 880         sigaddset(&blockmask, SIGHUP);
 881         sigaddset(&blockmask, SIGALRM);
 882
 883         memset(&sa, 0, sizeof(sa));
 884         sa.sa_mask = blockmask;
 885         sa.sa_handler = retry;
 886         sigaction(SIGALRM, &sa, NULL);
 887         sa.sa_handler = config;
 888         sigaction(SIGHUP, &sa, NULL);
 889         sa.sa_handler = reapchild;
 890         sigaction(SIGCHLD, &sa, NULL);
 891         sa.sa_handler = goaway;
 892         sigaction(SIGTERM, &sa, NULL);
 893         sa.sa_handler = goaway;
 894         sigaction(SIGINT, &sa,  NULL);
 895         sa.sa_handler = SIG_IGN;
 896         sigaction(SIGPIPE, &sa, NULL);
 897
 898         {
 899                 /* space for daemons to overwrite environment for ps */
 900 #define DUMMYSIZE       100
 901                 char dummy[DUMMYSIZE];
 902
 903                 (void)memset(dummy, 'x', DUMMYSIZE - 1);
 904                 dummy[DUMMYSIZE - 1] = '\0';
 905
 906                 (void)setenv("inetd_dummy", dummy, 1);
 907         }
 908
 909         for (;;) {
 910             int n, ctrl;
 911             fd_set readable;
 912
 913             if (nsock == 0) {
 914                 sigprocmask(SIG_BLOCK, &blockmask, NULL);
 915                 while (nsock == 0)
 916                     sigsuspend(&emptymask);
 917                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 918             }
 919             readable = allsock;
 920             if ((n = select(maxsock + 1, &readable, (fd_set *)0,
 921                 (fd_set *)0, (struct timeval *)0)) <= 0) {
 922                     if (n < 0 && errno != EINTR)
 923                         syslog(LOG_WARNING, "select: %m");
 924                     sleep(1);
 925                     continue;
 926             }
 927             for (sep = servtab; n && sep; sep = sep->se_next)
 928             if (sep->se_fd != -1 && FD_ISSET(sep->se_fd, &readable)) {
 929                 n--;
 930                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
 931                         /* Fixed AGC */
 932                         fcntl(sep->se_fd, F_SETFL, O_NDELAY);
 933                         /* --------- */
 934                         ctrl = accept(sep->se_fd, NULL, NULL);
 935                         fcntl(sep->se_fd, F_SETFL, 0);
 936                         if (ctrl < 0) {
 937                                 if (errno == EINTR || errno == EWOULDBLOCK)
 938                                         continue;
 939                                 syslog(LOG_WARNING, "accept (for %s): %m",
 940                                         sep->se_service);
 941                                 continue;
 942                         }
 943                 } else
 944                         ctrl = sep->se_fd;
 945                 sigprocmask(SIG_BLOCK, &blockmask, NULL);
 946                 pid = 0;
 947 #ifndef INETD_UNSUPPORT_BILTIN
 948                 dofork = (sep->se_bi == 0 || sep->se_bi->bi_fork);
 949 #endif
 950                 if (dofork) {
 951                         if (sep->se_count++ == 0)
 952                             (void)gettimeofday(&sep->se_time,
 953                                 (struct timezone *)0);
 954                         else if (sep->se_count >= sep->se_max) {
 955                                 struct timeval now;
 956
 957                                 (void)gettimeofday(&now, (struct timezone *)0);
 958                                 if (now.tv_sec - sep->se_time.tv_sec >
 959                                     CNT_INTVL) {
 960                                         sep->se_time = now;
 961                                         sep->se_count = 1;
 962                                 } else {
 963                                         syslog(LOG_ERR,
 964                         "%s/%s server failing (looping), service terminated",
 965                                             sep->se_service, sep->se_proto);
 966                                         FD_CLR(sep->se_fd, &allsock);
 967                                         (void) close(sep->se_fd);
 968                                         sep->se_fd = -1;
 969                                         sep->se_count = 0;
 970                                         nsock--;
 971                                         sigprocmask(SIG_SETMASK, &emptymask,
 972                                                     NULL);
 973                                         if (!timingout) {
 974                                                 timingout = 1;
 975                                                 alarm(RETRYTIME);
 976                                         }
 977                                         continue;
 978                                 }
 979                         }
 980                         pid = fork();
 981                 }
 982                 if (pid < 0) {
 983                         syslog(LOG_ERR, "fork: %m");
 984                         if (sep->se_socktype == SOCK_STREAM)
 985                                 close(ctrl);
 986                         sigprocmask(SIG_SETMASK, &emptymask, NULL);
 987                         sleep(1);
 988                         continue;
 989                 }
 990                 if (pid && sep->se_wait) {
 991                         sep->se_wait = pid;
 992                         FD_CLR(sep->se_fd, &allsock);
 993                         nsock--;
 994                 }
 995                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 996                 if (pid == 0) {
 997 #ifndef INETD_UNSUPPORT_BILTIN
 998                         if (sep->se_bi)
 999                                 (*sep->se_bi->bi_fn)(ctrl, sep);
1000                         else
1001 #endif
1002                               {
1003                                 if ((pwd = getpwnam(sep->se_user)) == NULL) {
1004                                         syslog_err_and_discard_dg(
1005                                                 sep->se_socktype,
1006                                                 "getpwnam: %s: No such user",
1007                                                 sep->se_user);
1008                                 }
1009                                 if (sep->se_group &&
1010                                     (grp = getgrnam(sep->se_group)) == NULL) {
1011                                         syslog_err_and_discard_dg(
1012                                                 sep->se_socktype,
1013                                                 "getgrnam: %s: No such group",
1014                                                 sep->se_group);
1015                                 }
1016                                 /*
1017                                  * Ok. There are four cases here:
1018                                  *   1. nonroot user, no group specified
1019                                  *   2. nonroot user, some group specified
1020                                  *   3. root user, no group specified
1021                                  *   4. root user, some group specified
1022                                  * In cases 2 and 4 we setgid to the specified
1023                                  * group. In cases 1 and 2 we run initgroups
1024                                  * to run with the groups of the given user.
1025                                  * In case 4 we do setgroups to run with the
1026                                  * given group. In case 3 we do nothing.
1027                                  */
1028                                 if (pwd->pw_uid) {
1029                                         if (sep->se_group)
1030                                                 pwd->pw_gid = grp->gr_gid;
1031                                         setgid((gid_t)pwd->pw_gid);
1032                                         initgroups(pwd->pw_name, pwd->pw_gid);
1033                                         setuid((uid_t)pwd->pw_uid);
1034                                 } else if (sep->se_group) {
1035                                         setgid((gid_t)grp->gr_gid);
1036                                         setgroups(1, &grp->gr_gid);
1037                                 }
1038                                 dup2(ctrl, 0);
1039                                 close(ctrl);
1040                                 dup2(0, 1);
1041                                 dup2(0, 2);
1042 #ifdef RLIMIT_NOFILE
1043                                 if (rlim_ofile.rlim_cur != rlim_ofile_cur) {
1044                                         if (setrlimit(RLIMIT_NOFILE,
1045                                                         &rlim_ofile) < 0)
1046                                                 syslog(LOG_ERR,"setrlimit: %m");
1047                                 }
1048 #endif
1049                                 for (ctrl = rlim_ofile_cur-1; --ctrl > 2; )
1050                                         (void)close(ctrl);
1051
1052                                 memset(&sa, 0, sizeof(sa));
1053                                 sa.sa_handler = SIG_DFL;
1054                                 sigaction(SIGPIPE, &sa, NULL);
1055
1056                                 execv(sep->se_server, sep->se_argv);
1057                                 syslog_err_and_discard_dg(sep->se_socktype,
1058                                         "execv %s: %m", sep->se_server);
1059                         }
1060                 }
1061                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1062                         close(ctrl);
1063             }
1064         }
1065 }
1066
1067
1068 /*
1069  * Internet services provided internally by inetd:
1070  */
1071 #define BUFSIZE 4096
1072
1073 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
1074 /* Echo service -- echo data back */
1075 static void
1076 echo_stream(int s, struct servtab *sep)
1077 {
1078         char buffer[BUFSIZE];
1079         int i;
1080
1081         setproctitle(sep->se_service, s);
1082         while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
1083             write(s, buffer, i) > 0)
1084                 ;
1085         exit(0);
1086 }
1087
1088 /* Echo service -- echo data back */
1089 static void
1090 echo_dg(int s, struct servtab *sep)
1091 {
1092         char buffer[BUFSIZE];
1093         int i;
1094         size_t size;
1095         struct sockaddr sa;
1096
1097         (void)sep;
1098
1099         size = sizeof(sa);
1100         if ((i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size)) < 0)
1101                 return;
1102         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1103 }
1104 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO */
1105
1106
1107 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
1108 /* Discard service -- ignore data */
1109 static void
1110 discard_stream(int s, struct servtab *sep)
1111 {
1112         char buffer[BUFSIZE];
1113
1114         setproctitle(sep->se_service, s);
1115         while ((errno = 0, read(s, buffer, sizeof(buffer)) > 0) ||
1116                         errno == EINTR)
1117                 ;
1118         exit(0);
1119 }
1120
1121 /* Discard service -- ignore data */
1122 static void
1123 discard_dg(int s, struct servtab *sep)
1124 {
1125         char buffer[BUFSIZE];
1126         (void)sep;
1127         read(s, buffer, sizeof(buffer));
1128 }
1129 #endif  /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD */
1130
1131
1132 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
1133 #include <ctype.h>
1134 #define LINESIZ 72
1135 static char ring[128];
1136 static char *endring;
1137
1138 static void
1139 initring(void)
1140 {
1141         int i;
1142
1143         endring = ring;
1144
1145         for (i = 0; i <= 128; ++i)
1146                 if (isprint(i))
1147                         *endring++ = i;
1148 }
1149
1150 /* Character generator */
1151 static void
1152 chargen_stream(int s, struct servtab *sep)
1153 {
1154         char *rs;
1155         int len;
1156         char text[LINESIZ+2];
1157
1158         setproctitle(sep->se_service, s);
1159
1160         if (!endring) {
1161                 initring();
1162                 rs = ring;
1163         }
1164
1165         text[LINESIZ] = '\r';
1166         text[LINESIZ + 1] = '\n';
1167         for (rs = ring;;) {
1168                 if ((len = endring - rs) >= LINESIZ)
1169                         BCOPY(rs, text, LINESIZ);
1170                 else {
1171                         BCOPY(rs, text, len);
1172                         BCOPY(ring, text + len, LINESIZ - len);
1173                 }
1174                 if (++rs == endring)
1175                         rs = ring;
1176                 if (write(s, text, sizeof(text)) != sizeof(text))
1177                         break;
1178         }
1179         exit(0);
1180 }
1181
1182 /* Character generator */
1183 static void
1184 chargen_dg(int s, struct servtab *sep)
1185 {
1186         struct sockaddr sa;
1187         static char *rs;
1188         size_t len, size;
1189         char text[LINESIZ+2];
1190
1191         (void)sep;
1192
1193         if (endring == 0) {
1194                 initring();
1195                 rs = ring;
1196         }
1197
1198         size = sizeof(sa);
1199         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1200                 return;
1201
1202         if ((len = endring - rs) >= LINESIZ)
1203                 BCOPY(rs, text, LINESIZ);
1204         else {
1205                 BCOPY(rs, text, len);
1206                 BCOPY(ring, text + len, LINESIZ - len);
1207         }
1208         if (++rs == endring)
1209                 rs = ring;
1210         text[LINESIZ] = '\r';
1211         text[LINESIZ + 1] = '\n';
1212         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1213 }
1214 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN */
1215
1216
1217 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
1218 /*
1219  * Return a machine readable date and time, in the form of the
1220  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1221  * returns the number of seconds since midnight, Jan 1, 1970,
1222  * we must add 2208988800 seconds to this figure to make up for
1223  * some seventy years Bell Labs was asleep.
1224  */
1225
1226 static long
1227 machtime(void)
1228 {
1229         struct timeval tv;
1230
1231         if (gettimeofday(&tv, (struct timezone *)0) < 0) {
1232                 fprintf(stderr, "Unable to get time of day\n");
1233                 return (0L);
1234         }
1235         return (htonl((long)tv.tv_sec + 2208988800UL));
1236 }
1237
1238 static void
1239 machtime_stream(int s, struct servtab *sep)
1240 {
1241         long result;
1242         (void)sep;
1243
1244         result = machtime();
1245         write(s, (char *) &result, sizeof(result));
1246 }
1247
1248 static void
1249 machtime_dg(int s, struct servtab *sep)
1250 {
1251         long result;
1252         struct sockaddr sa;
1253         size_t size;
1254         (void)sep;
1255
1256         size = sizeof(sa);
1257         if (recvfrom(s, (char *)&result, sizeof(result), 0, &sa, &size) < 0)
1258                 return;
1259         result = machtime();
1260         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1261 }
1262 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME */
1263
1264
1265 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
1266 /* Return human-readable time of day */
1267 static int
1268 human_readable_time_sprintf(char *buffer)
1269 {
1270         time_t clocc = time(NULL);
1271
1272         return sprintf(buffer, "%.24s\r\n", ctime(&clocc));
1273 }
1274
1275 static void
1276 daytime_stream(int s, struct servtab *sep)
1277 {
1278         char buffer[256];
1279         size_t st = human_readable_time_sprintf(buffer);
1280
1281         (void)sep;
1282
1283         write(s, buffer, st);
1284 }
1285
1286 /* Return human-readable time of day */
1287 static void
1288 daytime_dg(int s, struct servtab *sep)
1289 {
1290         char buffer[256];
1291         struct sockaddr sa;
1292         size_t size;
1293
1294         (void)sep;
1295
1296         size = sizeof(sa);
1297         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1298                 return;
1299         size = human_readable_time_sprintf(buffer);
1300         sendto(s, buffer, size, 0, &sa, sizeof(sa));
1301 }
1302 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME */