networking/inetd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*      $Slackware: inetd.c 1.79s 2001/02/06 13:18:00 volkerdi Exp $    */
   3 /*      $OpenBSD: inetd.c,v 1.79 2001/01/30 08:30:57 deraadt Exp $      */
   4 /*      $NetBSD: inetd.c,v 1.11 1996/02/22 11:14:41 mycroft Exp $       */
   5 /* Busybox port by Vladimir Oleynik (C) 2001-2005 <dzo@simtreas.ru>     */
   6 /*
   7  * Copyright (c) 1983,1991 The Regents of the University of California.
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 /* Inetd - Internet super-server
  40  *
  41  * This program invokes all internet services as needed.
  42  * connection-oriented services are invoked each time a
  43  * connection is made, by creating a process.  This process
  44  * is passed the connection as file descriptor 0 and is
  45  * expected to do a getpeername to find out the source host
  46  * and port.
  47  *
  48  * Datagram oriented services are invoked when a datagram
  49  * arrives; a process is created and passed a pending message
  50  * on file descriptor 0.  Datagram servers may either connect
  51  * to their peer, freeing up the original socket for inetd
  52  * to receive further messages on, or "take over the socket",
  53  * processing all arriving datagrams and, eventually, timing
  54  * out.  The first type of server is said to be "multi-threaded";
  55  * the second type of server "single-threaded".
  56  *
  57  * Inetd uses a configuration file which is read at startup
  58  * and, possibly, at some later time in response to a hangup signal.
  59  * The configuration file is "free format" with fields given in the
  60  * order shown below.  Continuation lines for an entry must begin with
  61  * a space or tab.  All fields must be present in each entry.
  62  *
  63  *      service name                    must be in /etc/services
  64  *      socket type                     stream/dgram/raw/rdm/seqpacket
  65  *      protocol                        must be in /etc/protocols
  66  *      wait/nowait[.max]               single-threaded/multi-threaded, max #
  67  *      user[.group] or user[:group]    user/group to run daemon as
  68  *      server program                  full path name
  69  *      server program arguments        maximum of MAXARGS (20)
  70  *
  71  * For RPC services
  72  *      service name/version            must be in /etc/rpc
  73  *      socket type                     stream/dgram/raw/rdm/seqpacket
  74  *      protocol                        must be in /etc/protocols
  75  *      wait/nowait[.max]               single-threaded/multi-threaded
  76  *      user[.group] or user[:group]    user to run daemon as
  77  *      server program                  full path name
  78  *      server program arguments        maximum of MAXARGS (20)
  79  *
  80  * For non-RPC services, the "service name" can be of the form
  81  * hostaddress:servicename, in which case the hostaddress is used
  82  * as the host portion of the address to listen on.  If hostaddress
  83  * consists of a single `*' character, INADDR_ANY is used.
  84  *
  85  * A line can also consist of just
  86  *      hostaddress:
  87  * where hostaddress is as in the preceding paragraph.  Such a line must
  88  * have no further fields; the specified hostaddress is remembered and
  89  * used for all further lines that have no hostaddress specified,
  90  * until the next such line (or EOF).  (This is why * is provided to
  91  * allow explicit specification of INADDR_ANY.)  A line
  92  *      *:
  93  * is implicitly in effect at the beginning of the file.
  94  *
  95  * The hostaddress specifier may (and often will) contain dots;
  96  * the service name must not.
  97  *
  98  * For RPC services, host-address specifiers are accepted and will
  99  * work to some extent; however, because of limitations in the
 100  * portmapper interface, it will not work to try to give more than
 101  * one line for any given RPC service, even if the host-address
 102  * specifiers are different.
 103  *
 104  * Comment lines are indicated by a `#' in column 1.
 105  */
 106
 107 /* inetd rules for passing file descriptors to children
 108  * (http://www.freebsd.org/cgi/man.cgi?query=inetd):
 109  *
 110  * The wait/nowait entry specifies whether the server that is invoked by
 111  * inetd will take over the socket associated with the service access point,
 112  * and thus whether inetd should wait for the server to exit before listen-
 113  * ing for new service requests.  Datagram servers must use "wait", as
 114  * they are always invoked with the original datagram socket bound to the
 115  * specified service address.  These servers must read at least one datagram
 116  * from the socket before exiting.  If a datagram server connects to its
 117  * peer, freeing the socket so inetd can receive further messages on the
 118  * socket, it is said to be a "multi-threaded" server; it should read one
 119  * datagram from the socket and create a new socket connected to the peer.
 120  * It should fork, and the parent should then exit to allow inetd to check
 121  * for new service requests to spawn new servers.  Datagram servers which
 122  * process all incoming datagrams on a socket and eventually time out are
 123  * said to be "single-threaded".  The comsat(8), (biff(1)) and talkd(8)
 124  * utilities are both examples of the latter type of datagram server.  The
 125  * tftpd(8) utility is an example of a multi-threaded datagram server.
 126  *
 127  * Servers using stream sockets generally are multi-threaded and use the
 128  * "nowait" entry. Connection requests for these services are accepted by
 129  * inetd, and the server is given only the newly-accepted socket connected
 130  * to a client of the service.  Most stream-based services operate in this
 131  * manner.  Stream-based servers that use "wait" are started with the lis-
 132  * tening service socket, and must accept at least one connection request
 133  * before exiting.  Such a server would normally accept and process incoming
 134  * connection requests until a timeout.
 135  */
 136
 137 /* Here's the scoop concerning the user[.:]group feature:
 138  *
 139  * 1) set-group-option off.
 140  *
 141  *      a) user = root: NO setuid() or setgid() is done
 142  *
 143  *      b) other:       setgid(primary group as found in passwd)
 144  *                      initgroups(name, primary group)
 145  *                      setuid()
 146  *
 147  * 2) set-group-option on.
 148  *
 149  *      a) user = root: setgid(specified group)
 150  *                      NO initgroups()
 151  *                      NO setuid()
 152  *
 153  *      b) other:       setgid(specified group)
 154  *                      initgroups(name, specified group)
 155  *                      setuid()
 156  */
 157
 158 #include "libbb.h"
 159 #include <syslog.h>
 160 #include <sys/un.h>
 161
 162 //#define ENABLE_FEATURE_INETD_RPC 1
 163 //#define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO 1
 164 //#define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD 1
 165 //#define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME 1
 166 //#define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME 1
 167 //#define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN 1
 168 //#define ENABLE_FEATURE_IPV6 1
 169
 170 #if ENABLE_FEATURE_INETD_RPC
 171 #include <rpc/rpc.h>
 172 #include <rpc/pmap_clnt.h>
 173 #endif
 174
 175 extern char **environ;
 176
 177
 178 #define _PATH_INETDPID  "/var/run/inetd.pid"
 179
 180 #define CNT_INTVL       60              /* servers in CNT_INTVL sec. */
 181 #define RETRYTIME       (60*10)         /* retry after bind or server fail */
 182
 183 #ifndef RLIMIT_NOFILE
 184 #define RLIMIT_NOFILE   RLIMIT_OFILE
 185 #endif
 186
 187 #ifndef OPEN_MAX
 188 #define OPEN_MAX        64
 189 #endif
 190
 191 /* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
 192 #define FD_MARGIN       8
 193 static rlim_t rlim_ofile_cur = OPEN_MAX;
 194 static struct rlimit rlim_ofile;
 195
 196
 197 /* Check unsupporting builtin */
 198 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
 199         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD || \
 200         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME || \
 201         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME || \
 202         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 203 # define INETD_FEATURE_ENABLED
 204 #endif
 205
 206 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
 207         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD || \
 208         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 209 # define INETD_SETPROCTITLE
 210 #endif
 211
 212 typedef struct servtab {
 213         char *se_hostaddr;                    /* host address to listen on */
 214         char *se_service;                     /* name of service */
 215         int se_socktype;                      /* type of socket to use */
 216         int se_family;                        /* address family */
 217         char *se_proto;                       /* protocol used */
 218 #if ENABLE_FEATURE_INETD_RPC
 219         int se_rpcprog;                       /* rpc program number */
 220         int se_rpcversl;                      /* rpc program lowest version */
 221         int se_rpcversh;                      /* rpc program highest version */
 222 #define isrpcservice(sep)       ((sep)->se_rpcversl != 0)
 223 #else
 224 #define isrpcservice(sep)       0
 225 #endif
 226         pid_t se_wait;                        /* single threaded server */
 227         short se_checked;                     /* looked at during merge */
 228         char *se_user;                        /* user name to run as */
 229         char *se_group;                       /* group name to run as */
 230 #ifdef INETD_FEATURE_ENABLED
 231         const struct builtin *se_bi;          /* if built-in, description */
 232 #endif
 233         char *se_server;                      /* server program */
 234 #define MAXARGV 20
 235         char *se_argv[MAXARGV + 1];           /* program arguments */
 236         int se_fd;                            /* open descriptor */
 237         union {
 238                 struct sockaddr se_un_ctrladdr;
 239                 struct sockaddr_in se_un_ctrladdr_in;
 240 #if ENABLE_FEATURE_IPV6
 241                 struct sockaddr_in6 se_un_ctrladdr_in6;
 242 #endif
 243                 struct sockaddr_un se_un_ctrladdr_un;
 244         } se_un;                              /* bound address */
 245 #define se_ctrladdr     se_un.se_un_ctrladdr
 246 #define se_ctrladdr_in  se_un.se_un_ctrladdr_in
 247 #define se_ctrladdr_in6 se_un.se_un_ctrladdr_in6
 248 #define se_ctrladdr_un  se_un.se_un_ctrladdr_un
 249         int se_ctrladdr_size;
 250         int se_max;                           /* max # of instances of this service */
 251         int se_count;                         /* number started since se_time */
 252         struct timeval se_time;               /* start of se_count */
 253         struct servtab *se_next;
 254 } servtab_t;
 255
 256 static servtab_t *servtab;
 257
 258 #ifdef INETD_FEATURE_ENABLED
 259 struct builtin {
 260         const char *bi_service;               /* internally provided service name */
 261         int bi_socktype;                      /* type of socket supported */
 262         short bi_fork;                        /* 1 if should fork before call */
 263         short bi_wait;                        /* 1 if should wait for child */
 264         void (*bi_fn) (int, servtab_t *);
 265 };
 266
 267                 /* Echo received data */
 268 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
 269 static void echo_stream(int, servtab_t *);
 270 static void echo_dg(int, servtab_t *);
 271 #endif
 272                 /* Internet /dev/null */
 273 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
 274 static void discard_stream(int, servtab_t *);
 275 static void discard_dg(int, servtab_t *);
 276 #endif
 277                 /* Return 32 bit time since 1900 */
 278 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
 279 static void machtime_stream(int, servtab_t *);
 280 static void machtime_dg(int, servtab_t *);
 281 #endif
 282                 /* Return human-readable time */
 283 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
 284 static void daytime_stream(int, servtab_t *);
 285 static void daytime_dg(int, servtab_t *);
 286 #endif
 287                 /* Familiar character generator */
 288 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 289 static void chargen_stream(int, servtab_t *);
 290 static void chargen_dg(int, servtab_t *);
 291 #endif
 292
 293 static const struct builtin builtins[] = {
 294 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
 295         /* Echo received data */
 296         {"echo", SOCK_STREAM, 1, 0, echo_stream,},
 297         {"echo", SOCK_DGRAM, 0, 0, echo_dg,},
 298 #endif
 299 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
 300         /* Internet /dev/null */
 301         {"discard", SOCK_STREAM, 1, 0, discard_stream,},
 302         {"discard", SOCK_DGRAM, 0, 0, discard_dg,},
 303 #endif
 304 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
 305         /* Return 32 bit time since 1900 */
 306         {"time", SOCK_STREAM, 0, 0, machtime_stream,},
 307         {"time", SOCK_DGRAM, 0, 0, machtime_dg,},
 308 #endif
 309 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
 310         /* Return human-readable time */
 311         {"daytime", SOCK_STREAM, 0, 0, daytime_stream,},
 312         {"daytime", SOCK_DGRAM, 0, 0, daytime_dg,},
 313 #endif
 314 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 315         /* Familiar character generator */
 316         {"chargen", SOCK_STREAM, 1, 0, chargen_stream,},
 317         {"chargen", SOCK_DGRAM, 0, 0, chargen_dg,},
 318 #endif
 319         {NULL, 0, 0, 0, NULL}
 320 };
 321 #endif /* INETD_FEATURE_ENABLED */
 322
 323 static int global_queuelen = 128;
 324 static int nsock, maxsock;
 325 static fd_set allsock;
 326 static int toomany;
 327 static int timingout;
 328 static struct servent *sp;
 329 static uid_t uid;
 330
 331 static const char *config_filename = "/etc/inetd.conf";
 332
 333 static FILE *fconfig;
 334 static char *defhost;
 335
 336 /* xstrdup(NULL) returns NULL, but this one
 337  * will return newly-allocated "" if called with NULL arg
 338  * TODO: audit whether this makes any real difference
 339  */
 340 static char *xxstrdup(char *cp)
 341 {
 342         return xstrdup(cp ? cp : "");
 343 }
 344
 345 static int setconfig(void)
 346 {
 347         free(defhost);
 348         defhost = xstrdup("*");
 349         if (fconfig != NULL) {
 350                 fseek(fconfig, 0L, SEEK_SET);
 351                 return 1;
 352         }
 353         fconfig = fopen(config_filename, "r");
 354         return (fconfig != NULL);
 355 }
 356
 357 static void endconfig(void)
 358 {
 359         if (fconfig) {
 360                 (void) fclose(fconfig);
 361                 fconfig = NULL;
 362         }
 363         free(defhost);
 364         defhost = 0;
 365 }
 366
 367 #if ENABLE_FEATURE_INETD_RPC
 368 static void register_rpc(servtab_t *sep)
 369 {
 370         int n;
 371         struct sockaddr_in ir_sin;
 372         struct protoent *pp;
 373         socklen_t size;
 374
 375         if ((pp = getprotobyname(sep->se_proto + 4)) == NULL) {
 376                 bb_perror_msg("%s: getproto", sep->se_proto);
 377                 return;
 378         }
 379         size = sizeof ir_sin;
 380         if (getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, &size) < 0) {
 381                 bb_perror_msg("%s/%s: getsockname",
 382                                 sep->se_service, sep->se_proto);
 383                 return;
 384         }
 385
 386         for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
 387                 (void) pmap_unset(sep->se_rpcprog, n);
 388                 if (!pmap_set(sep->se_rpcprog, n, pp->p_proto, ntohs(ir_sin.sin_port)))
 389                         bb_perror_msg("%s %s: pmap_set: %u %u %u %u",
 390                                         sep->se_service, sep->se_proto,
 391                                         sep->se_rpcprog, n, pp->p_proto, ntohs(ir_sin.sin_port));
 392         }
 393 }
 394
 395 static void unregister_rpc(servtab_t *sep)
 396 {
 397         int n;
 398
 399         for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
 400                 if (!pmap_unset(sep->se_rpcprog, n))
 401                         bb_error_msg("pmap_unset(%u, %u)", sep->se_rpcprog, n);
 402         }
 403 }
 404 #endif /* FEATURE_INETD_RPC */
 405
 406 static void freeconfig(servtab_t *cp)
 407 {
 408         int i;
 409
 410         free(cp->se_hostaddr);
 411         free(cp->se_service);
 412         free(cp->se_proto);
 413         free(cp->se_user);
 414         free(cp->se_group);
 415         free(cp->se_server);
 416         for (i = 0; i < MAXARGV; i++)
 417                 free(cp->se_argv[i]);
 418 }
 419
 420 static int bump_nofile(void)
 421 {
 422 #define FD_CHUNK        32
 423
 424         struct rlimit rl;
 425
 426         if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
 427                 bb_perror_msg("getrlimit");
 428                 return -1;
 429         }
 430         rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
 431         rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
 432         if (rl.rlim_cur <= rlim_ofile_cur) {
 433                 bb_error_msg("bump_nofile: cannot extend file limit, max = %d",
 434                                                 (int) rl.rlim_cur);
 435                 return -1;
 436         }
 437
 438         if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
 439                 bb_perror_msg("setrlimit");
 440                 return -1;
 441         }
 442
 443         rlim_ofile_cur = rl.rlim_cur;
 444         return 0;
 445 }
 446
 447 static void setup(servtab_t *sep)
 448 {
 449         int r;
 450
 451         sep->se_fd = socket(sep->se_family, sep->se_socktype, 0);
 452         if (sep->se_fd < 0) {
 453                 bb_perror_msg("%s/%s: socket", sep->se_service, sep->se_proto);
 454                 return;
 455         }
 456         setsockopt_reuseaddr(sep->se_fd);
 457
 458 #if ENABLE_FEATURE_INETD_RPC
 459         if (isrpcservice(sep)) {
 460                 struct passwd *pwd;
 461
 462                 /*
 463                  * for RPC services, attempt to use a reserved port
 464                  * if they are going to be running as root.
 465                  *
 466                  * Also, zero out the port for all RPC services; let bind()
 467                  * find one.
 468                  */
 469                 sep->se_ctrladdr_in.sin_port = 0;
 470                 if (sep->se_user && (pwd = getpwnam(sep->se_user)) &&
 471                                 pwd->pw_uid == 0 && uid == 0)
 472                         r = bindresvport(sep->se_fd, &sep->se_ctrladdr_in);
 473                 else {
 474                         r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 475                         if (r == 0) {
 476                                 socklen_t len = sep->se_ctrladdr_size;
 477                                 int saveerrno = errno;
 478
 479                                 /* update se_ctrladdr_in.sin_port */
 480                                 r = getsockname(sep->se_fd, &sep->se_ctrladdr, &len);
 481                                 if (r <= 0)
 482                                         errno = saveerrno;
 483                         }
 484                 }
 485         } else
 486 #endif
 487                 r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 488         if (r < 0) {
 489                 bb_perror_msg("%s/%s (%d): bind",
 490                                 sep->se_service, sep->se_proto, sep->se_ctrladdr.sa_family);
 491                 close(sep->se_fd);
 492                 sep->se_fd = -1;
 493                 if (!timingout) {
 494                         timingout = 1;
 495                         alarm(RETRYTIME);
 496                 }
 497                 return;
 498         }
 499         if (sep->se_socktype == SOCK_STREAM)
 500                 listen(sep->se_fd, global_queuelen);
 501
 502         FD_SET(sep->se_fd, &allsock);
 503         nsock++;
 504         if (sep->se_fd > maxsock) {
 505                 maxsock = sep->se_fd;
 506                 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
 507                         bump_nofile();
 508         }
 509 }
 510
 511 static char *nextline(void)
 512 {
 513 #define line bb_common_bufsiz1
 514
 515         char *cp;
 516         FILE *fd = fconfig;
 517
 518         if (fgets(line, sizeof(line), fd) == NULL)
 519                 return NULL;
 520         cp = strchr(line, '\n');
 521         if (cp)
 522                 *cp = '\0';
 523         return line;
 524 }
 525
 526 static char *skip(char **cpp) /* int report; */
 527 {
 528         char *cp = *cpp;
 529         char *start;
 530
 531 /* erp: */
 532         if (*cpp == NULL) {
 533                 /* if (report) */
 534                 /* bb_error_msg("syntax error in inetd config file"); */
 535                 return NULL;
 536         }
 537
 538  again:
 539         while (*cp == ' ' || *cp == '\t')
 540                 cp++;
 541         if (*cp == '\0') {
 542                 int c;
 543
 544                 c = getc(fconfig);
 545                 ungetc(c, fconfig);
 546                 if (c == ' ' || c == '\t') {
 547                         cp = nextline();
 548                         if (cp)
 549                                 goto again;
 550                 }
 551                 *cpp = NULL;
 552                 /* goto erp; */
 553                 return NULL;
 554         }
 555         start = cp;
 556         while (*cp && *cp != ' ' && *cp != '\t')
 557                 cp++;
 558         if (*cp != '\0')
 559                 *cp++ = '\0';
 560         /* if ((*cpp = cp) == NULL) */
 561         /* goto erp; */
 562
 563         *cpp = cp;
 564         return start;
 565 }
 566
 567 static servtab_t *new_servtab(void)
 568 {
 569         return xmalloc(sizeof(servtab_t));
 570 }
 571
 572 static servtab_t *dupconfig(servtab_t *sep)
 573 {
 574         servtab_t *newtab;
 575         int argc;
 576
 577         newtab = new_servtab();
 578         memset(newtab, 0, sizeof(servtab_t));
 579         newtab->se_service = xstrdup(sep->se_service);
 580         newtab->se_socktype = sep->se_socktype;
 581         newtab->se_family = sep->se_family;
 582         newtab->se_proto = xstrdup(sep->se_proto);
 583 #if ENABLE_FEATURE_INETD_RPC
 584         newtab->se_rpcprog = sep->se_rpcprog;
 585         newtab->se_rpcversl = sep->se_rpcversl;
 586         newtab->se_rpcversh = sep->se_rpcversh;
 587 #endif
 588         newtab->se_wait = sep->se_wait;
 589         newtab->se_user = xstrdup(sep->se_user);
 590         newtab->se_group = xstrdup(sep->se_group);
 591 #ifdef INETD_FEATURE_ENABLED
 592         newtab->se_bi = sep->se_bi;
 593 #endif
 594         newtab->se_server = xstrdup(sep->se_server);
 595
 596         for (argc = 0; argc <= MAXARGV; argc++)
 597                 newtab->se_argv[argc] = xstrdup(sep->se_argv[argc]);
 598         newtab->se_max = sep->se_max;
 599
 600         return newtab;
 601 }
 602
 603 static servtab_t *getconfigent(void)
 604 {
 605         servtab_t *sep;
 606         int argc;
 607         char *cp, *arg;
 608         char *hostdelim;
 609         servtab_t *nsep;
 610         servtab_t *psep;
 611
 612         sep = new_servtab();
 613
 614         /* memset(sep, 0, sizeof *sep); */
 615  more:
 616         /* freeconfig(sep); */
 617
 618         while ((cp = nextline()) && *cp == '#') /* skip comment line */;
 619         if (cp == NULL) {
 620                 /* free(sep); */
 621                 return NULL;
 622         }
 623
 624         memset((char *) sep, 0, sizeof *sep);
 625         arg = skip(&cp);
 626         if (arg == NULL) {
 627                 /* A blank line. */
 628                 goto more;
 629         }
 630
 631         /* Check for a host name. */
 632         hostdelim = strrchr(arg, ':');
 633         if (hostdelim) {
 634                 *hostdelim = '\0';
 635                 sep->se_hostaddr = xstrdup(arg);
 636                 arg = hostdelim + 1;
 637                 /*
 638                  * If the line is of the form `host:', then just change the
 639                  * default host for the following lines.
 640                  */
 641                 if (*arg == '\0') {
 642                         arg = skip(&cp);
 643                         if (cp == NULL) {
 644                                 free(defhost);
 645                                 defhost = sep->se_hostaddr;
 646                                 goto more;
 647                         }
 648                 }
 649         } else
 650                 sep->se_hostaddr = xxstrdup(defhost);
 651
 652         sep->se_service = xxstrdup(arg);
 653         arg = skip(&cp);
 654
 655         if (strcmp(arg, "stream") == 0)
 656                 sep->se_socktype = SOCK_STREAM;
 657         else if (strcmp(arg, "dgram") == 0)
 658                 sep->se_socktype = SOCK_DGRAM;
 659         else if (strcmp(arg, "rdm") == 0)
 660                 sep->se_socktype = SOCK_RDM;
 661         else if (strcmp(arg, "seqpacket") == 0)
 662                 sep->se_socktype = SOCK_SEQPACKET;
 663         else if (strcmp(arg, "raw") == 0)
 664                 sep->se_socktype = SOCK_RAW;
 665         else
 666                 sep->se_socktype = -1;
 667
 668         sep->se_proto = xxstrdup(skip(&cp));
 669
 670         if (strcmp(sep->se_proto, "unix") == 0) {
 671                 sep->se_family = AF_UNIX;
 672         } else {
 673                 sep->se_family = AF_INET;
 674                 if (sep->se_proto[strlen(sep->se_proto) - 1] == '6')
 675 #if ENABLE_FEATURE_IPV6
 676                         sep->se_family = AF_INET6;
 677 #else
 678                         bb_error_msg("%s: IPV6 not supported", sep->se_proto);
 679 #endif
 680                 if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
 681 #if ENABLE_FEATURE_INETD_RPC
 682                         char *p, *ccp;
 683                         long l;
 684
 685                         p = strchr(sep->se_service, '/');
 686                         if (p == 0) {
 687                                 bb_error_msg("%s: no rpc version", sep->se_service);
 688                                 goto more;
 689                         }
 690                         *p++ = '\0';
 691                         l = strtol(p, &ccp, 0);
 692                         if (ccp == p || l < 0 || l > INT_MAX) {
 693  badafterall:
 694                                 bb_error_msg("%s/%s: bad rpc version", sep->se_service, p);
 695                                 goto more;
 696                         }
 697                         sep->se_rpcversl = sep->se_rpcversh = l;
 698                         if (*ccp == '-') {
 699                                 p = ccp + 1;
 700                                 l = strtol(p, &ccp, 0);
 701                                 if (ccp == p || l < 0 || l > INT_MAX || l < sep->se_rpcversl || *ccp)
 702                                         goto badafterall;
 703                                 sep->se_rpcversh = l;
 704                         } else if (*ccp != '\0')
 705                                 goto badafterall;
 706 #else
 707                         bb_error_msg("%s: rpc services not supported", sep->se_service);
 708 #endif
 709                 }
 710         }
 711         arg = skip(&cp);
 712         if (arg == NULL)
 713                 goto more;
 714
 715         {
 716                 char *s = strchr(arg, '.');
 717                 if (s) {
 718                         *s++ = '\0';
 719                         sep->se_max = xatoi(s);
 720                 } else
 721                         sep->se_max = toomany;
 722         }
 723         sep->se_wait = strcmp(arg, "wait") == 0;
 724         /* if ((arg = skip(&cp, 1)) == NULL) */
 725         /* goto more; */
 726         sep->se_user = xxstrdup(skip(&cp));
 727         arg = strchr(sep->se_user, '.');
 728         if (arg == NULL)
 729                 arg = strchr(sep->se_user, ':');
 730         if (arg) {
 731                 *arg++ = '\0';
 732                 sep->se_group = xstrdup(arg);
 733         }
 734         /* if ((arg = skip(&cp, 1)) == NULL) */
 735         /* goto more; */
 736
 737         sep->se_server = xxstrdup(skip(&cp));
 738         if (strcmp(sep->se_server, "internal") == 0) {
 739 #ifdef INETD_FEATURE_ENABLED
 740                 const struct builtin *bi;
 741
 742                 for (bi = builtins; bi->bi_service; bi++)
 743                         if (bi->bi_socktype == sep->se_socktype &&
 744                                         strcmp(bi->bi_service, sep->se_service) == 0)
 745                                 break;
 746                 if (bi->bi_service == 0) {
 747                         bb_error_msg("internal service %s unknown", sep->se_service);
 748                         goto more;
 749                 }
 750                 sep->se_bi = bi;
 751                 sep->se_wait = bi->bi_wait;
 752 #else
 753                 bb_perror_msg("internal service %s unknown", sep->se_service);
 754                 goto more;
 755 #endif
 756         }
 757 #ifdef INETD_FEATURE_ENABLED
 758                 else
 759                 sep->se_bi = NULL;
 760 #endif
 761         argc = 0;
 762         for (arg = skip(&cp); cp; arg = skip(&cp)) {
 763                 if (argc < MAXARGV)
 764                         sep->se_argv[argc++] = xxstrdup(arg);
 765         }
 766         while (argc <= MAXARGV)
 767                 sep->se_argv[argc++] = NULL;
 768
 769         /*
 770          * Now that we've processed the entire line, check if the hostname
 771          * specifier was a comma separated list of hostnames. If so
 772          * we'll make new entries for each address.
 773          */
 774         while ((hostdelim = strrchr(sep->se_hostaddr, ',')) != NULL) {
 775                 nsep = dupconfig(sep);
 776
 777                 /*
 778                  * NULL terminate the hostname field of the existing entry,
 779                  * and make a dup for the new entry.
 780                  */
 781                 *hostdelim++ = '\0';
 782                 nsep->se_hostaddr = xstrdup(hostdelim);
 783
 784                 nsep->se_next = sep->se_next;
 785                 sep->se_next = nsep;
 786         }
 787
 788         nsep = sep;
 789         while (nsep != NULL) {
 790                 nsep->se_checked = 1;
 791                 if (nsep->se_family == AF_INET) {
 792                         if (LONE_CHAR(nsep->se_hostaddr, '*'))
 793                                 nsep->se_ctrladdr_in.sin_addr.s_addr = INADDR_ANY;
 794                         else if (!inet_aton(nsep->se_hostaddr, &nsep->se_ctrladdr_in.sin_addr)) {
 795                                 struct hostent *hp;
 796
 797                                 hp = gethostbyname(nsep->se_hostaddr);
 798                                 if (hp == 0) {
 799                                         bb_error_msg("%s: unknown host", nsep->se_hostaddr);
 800                                         nsep->se_checked = 0;
 801                                         goto skip;
 802                                 } else if (hp->h_addrtype != AF_INET) {
 803                                         bb_error_msg("%s: address isn't an Internet "
 804                                                                   "address", nsep->se_hostaddr);
 805                                         nsep->se_checked = 0;
 806                                         goto skip;
 807                                 } else {
 808                                         int i = 1;
 809
 810                                         memmove(&nsep->se_ctrladdr_in.sin_addr,
 811                                                                    hp->h_addr_list[0], sizeof(struct in_addr));
 812                                         while (hp->h_addr_list[i] != NULL) {
 813                                                 psep = dupconfig(nsep);
 814                                                 psep->se_hostaddr = xxstrdup(nsep->se_hostaddr);
 815                                                 psep->se_checked = 1;
 816                                                 memmove(&psep->se_ctrladdr_in.sin_addr,
 817                                                                      hp->h_addr_list[i], sizeof(struct in_addr));
 818                                                 psep->se_ctrladdr_size = sizeof(psep->se_ctrladdr_in);
 819                                                 i++;
 820                                                 /* Prepend to list, don't want to look up */
 821                                                 /* its hostname again. */
 822                                                 psep->se_next = sep;
 823                                                 sep = psep;
 824                                         }
 825                                 }
 826                         }
 827                 }
 828 /* XXX BUG?: is this skip: label supposed to remain? */
 829  skip:
 830                 nsep = nsep->se_next;
 831         }
 832
 833         /*
 834          * Finally, free any entries which failed the gethostbyname
 835          * check.
 836          */
 837         psep = NULL;
 838         nsep = sep;
 839         while (nsep != NULL) {
 840                 servtab_t *tsep;
 841
 842                 if (nsep->se_checked == 0) {
 843                         tsep = nsep;
 844                         if (psep == NULL) {
 845                                 sep = nsep->se_next;
 846                                 nsep = sep;
 847                         } else {
 848                                 nsep = nsep->se_next;
 849                                 psep->se_next = nsep;
 850                         }
 851                         freeconfig(tsep);
 852                 } else {
 853                         nsep->se_checked = 0;
 854                         psep = nsep;
 855                         nsep = nsep->se_next;
 856                 }
 857         }
 858
 859         return sep;
 860 }
 861
 862 #define Block_Using_Signals(m) do { \
 863         sigemptyset(&m); \
 864         sigaddset(&m, SIGCHLD); \
 865         sigaddset(&m, SIGHUP); \
 866         sigaddset(&m, SIGALRM); \
 867         sigprocmask(SIG_BLOCK, &m, NULL); \
 868 } while (0)
 869
 870 static servtab_t *enter(servtab_t *cp)
 871 {
 872         servtab_t *sep;
 873         sigset_t omask;
 874
 875         sep = new_servtab();
 876         *sep = *cp;
 877         sep->se_fd = -1;
 878 #if ENABLE_FEATURE_INETD_RPC
 879         sep->se_rpcprog = -1;
 880 #endif
 881         Block_Using_Signals(omask);
 882         sep->se_next = servtab;
 883         servtab = sep;
 884         sigprocmask(SIG_UNBLOCK, &omask, NULL);
 885         return sep;
 886 }
 887
 888 static int matchconf(servtab_t *old, servtab_t *new)
 889 {
 890         if (strcmp(old->se_service, new->se_service) != 0)
 891                 return 0;
 892
 893         if (strcmp(old->se_hostaddr, new->se_hostaddr) != 0)
 894                 return 0;
 895
 896         if (strcmp(old->se_proto, new->se_proto) != 0)
 897                 return 0;
 898
 899         /*
 900          * If the new servtab is bound to a specific address, check that the
 901          * old servtab is bound to the same entry. If the new service is not
 902          * bound to a specific address then the check of se_hostaddr above
 903          * is sufficient.
 904          */
 905
 906         if (old->se_family == AF_INET && new->se_family == AF_INET &&
 907                         memcmp(&old->se_ctrladdr_in.sin_addr,
 908                                         &new->se_ctrladdr_in.sin_addr,
 909                                         sizeof(new->se_ctrladdr_in.sin_addr)) != 0)
 910                 return 0;
 911
 912 #if ENABLE_FEATURE_IPV6
 913         if (old->se_family == AF_INET6 && new->se_family == AF_INET6 &&
 914                         memcmp(&old->se_ctrladdr_in6.sin6_addr,
 915                                         &new->se_ctrladdr_in6.sin6_addr,
 916                                         sizeof(new->se_ctrladdr_in6.sin6_addr)) != 0)
 917                 return 0;
 918 #endif
 919         return 1;
 920 }
 921
 922 static void config(int sig ATTRIBUTE_UNUSED)
 923 {
 924         servtab_t *sep, *cp, **sepp;
 925         sigset_t omask;
 926         size_t n;
 927         char protoname[10];
 928
 929         if (!setconfig()) {
 930                 bb_perror_msg("%s", config_filename);
 931                 return;
 932         }
 933         for (sep = servtab; sep; sep = sep->se_next)
 934                 sep->se_checked = 0;
 935         cp = getconfigent();
 936         while (cp != NULL) {
 937                 for (sep = servtab; sep; sep = sep->se_next)
 938                         if (matchconf(sep, cp))
 939                                 break;
 940
 941                 if (sep != 0) {
 942                         int i;
 943
 944 #define SWAP(type, a, b) do {type c=(type)a; a=(type)b; b=(type)c;} while (0)
 945
 946                         Block_Using_Signals(omask);
 947                         /*
 948                          * sep->se_wait may be holding the pid of a daemon
 949                          * that we're waiting for.  If so, don't overwrite
 950                          * it unless the config file explicitly says don't
 951                          * wait.
 952                          */
 953                         if (
 954 #ifdef INETD_FEATURE_ENABLED
 955                                 cp->se_bi == 0 &&
 956 #endif
 957                                 (sep->se_wait == 1 || cp->se_wait == 0))
 958                                 sep->se_wait = cp->se_wait;
 959                         SWAP(int, cp->se_max, sep->se_max);
 960                         SWAP(char *, sep->se_user, cp->se_user);
 961                         SWAP(char *, sep->se_group, cp->se_group);
 962                         SWAP(char *, sep->se_server, cp->se_server);
 963                         for (i = 0; i < MAXARGV; i++)
 964                                 SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
 965 #undef SWAP
 966
 967 #if ENABLE_FEATURE_INETD_RPC
 968                         if (isrpcservice(sep))
 969                                 unregister_rpc(sep);
 970                         sep->se_rpcversl = cp->se_rpcversl;
 971                         sep->se_rpcversh = cp->se_rpcversh;
 972 #endif
 973                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
 974                         freeconfig(cp);
 975                 } else {
 976                         sep = enter(cp);
 977                 }
 978                 sep->se_checked = 1;
 979
 980                 switch (sep->se_family) {
 981                 case AF_UNIX:
 982                         if (sep->se_fd != -1)
 983                                 break;
 984                         (void) unlink(sep->se_service);
 985                         n = strlen(sep->se_service);
 986                         if (n > sizeof sep->se_ctrladdr_un.sun_path - 1)
 987                                 n = sizeof sep->se_ctrladdr_un.sun_path - 1;
 988                         safe_strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n + 1);
 989                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
 990                         sep->se_ctrladdr_size = n + sizeof sep->se_ctrladdr_un.sun_family;
 991                         setup(sep);
 992                         break;
 993                 case AF_INET:
 994                         sep->se_ctrladdr_in.sin_family = AF_INET;
 995                         /* se_ctrladdr_in was set in getconfigent */
 996                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
 997
 998 #if ENABLE_FEATURE_INETD_RPC
 999                         if (isrpcservice(sep)) {
1000                                 struct rpcent *rp;
1001                                 // FIXME: atoi_or_else(str, 0) would be handy here
1002                                 sep->se_rpcprog = atoi(sep->se_service);
1003                                 if (sep->se_rpcprog == 0) {
1004                                         rp = getrpcbyname(sep->se_service);
1005                                         if (rp == 0) {
1006                                                 bb_error_msg("%s: unknown rpc service", sep->se_service);
1007                                                 goto serv_unknown;
1008                                         }
1009                                         sep->se_rpcprog = rp->r_number;
1010                                 }
1011                                 if (sep->se_fd == -1)
1012                                         setup(sep);
1013                                 if (sep->se_fd != -1)
1014                                         register_rpc(sep);
1015                         } else
1016 #endif
1017                         {
1018                                 uint16_t port = htons(atoi(sep->se_service));
1019                                 // FIXME: atoi_or_else(str, 0) would be handy here
1020                                 if (!port) {
1021                                          /*XXX*/ strncpy(protoname, sep->se_proto, sizeof(protoname));
1022                                         if (isdigit(protoname[strlen(protoname) - 1]))
1023                                                 protoname[strlen(protoname) - 1] = '\0';
1024                                         sp = getservbyname(sep->se_service, protoname);
1025                                         if (sp == 0) {
1026                                                 bb_error_msg("%s/%s: unknown service",
1027                                                                 sep->se_service, sep->se_proto);
1028                                                 goto serv_unknown;
1029                                         }
1030                                         port = sp->s_port;
1031                                 }
1032                                 if (port != sep->se_ctrladdr_in.sin_port) {
1033                                         sep->se_ctrladdr_in.sin_port = port;
1034                                         if (sep->se_fd != -1) {
1035                                                 FD_CLR(sep->se_fd, &allsock);
1036                                                 nsock--;
1037                                                 (void) close(sep->se_fd);
1038                                         }
1039                                         sep->se_fd = -1;
1040                                 }
1041                                 if (sep->se_fd == -1)
1042                                         setup(sep);
1043                         }
1044                         break;
1045 #if ENABLE_FEATURE_IPV6
1046                 case AF_INET6:
1047                         sep->se_ctrladdr_in6.sin6_family = AF_INET6;
1048                         /* se_ctrladdr_in was set in getconfigent */
1049                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in6;
1050
1051 #if ENABLE_FEATURE_INETD_RPC
1052                         if (isrpcservice(sep)) {
1053                                 struct rpcent *rp;
1054
1055                                 sep->se_rpcprog = atoi(sep->se_service);
1056                                 if (sep->se_rpcprog == 0) {
1057                                         rp = getrpcbyname(sep->se_service);
1058                                         if (rp == 0) {
1059                                                 bb_error_msg("%s: unknown rpc service", sep->se_service);
1060                                                 goto serv_unknown;
1061                                         }
1062                                         sep->se_rpcprog = rp->r_number;
1063                                 }
1064                                 if (sep->se_fd == -1)
1065                                         setup(sep);
1066                                 if (sep->se_fd != -1)
1067                                         register_rpc(sep);
1068                         } else
1069 #endif
1070                         {
1071                                 uint16_t port = htons(atoi(sep->se_service));
1072
1073                                 if (!port) {
1074                                          /*XXX*/ strncpy(protoname, sep->se_proto, sizeof(protoname));
1075                                         if (isdigit(protoname[strlen(protoname) - 1]))
1076                                                 protoname[strlen(protoname) - 1] = '\0';
1077                                         sp = getservbyname(sep->se_service, protoname);
1078                                         if (sp == 0) {
1079                                                 bb_error_msg("%s/%s: unknown service",
1080                                                                 sep->se_service, sep->se_proto);
1081                                                 goto serv_unknown;
1082                                         }
1083                                         port = sp->s_port;
1084                                 }
1085                                 if (port != sep->se_ctrladdr_in6.sin6_port) {
1086                                         sep->se_ctrladdr_in6.sin6_port = port;
1087                                         if (sep->se_fd != -1) {
1088                                                 FD_CLR(sep->se_fd, &allsock);
1089                                                 nsock--;
1090                                                 (void) close(sep->se_fd);
1091                                         }
1092                                         sep->se_fd = -1;
1093                                 }
1094                                 if (sep->se_fd == -1)
1095                                         setup(sep);
1096                         }
1097                         break;
1098 #endif /* FEATURE_IPV6 */
1099                 }
1100  serv_unknown:
1101                 if (cp->se_next != NULL) {
1102                         servtab_t *tmp = cp;
1103
1104                         cp = cp->se_next;
1105                         free(tmp);
1106                 } else {
1107                         free(cp);
1108                         cp = getconfigent();
1109                 }
1110         }
1111         endconfig();
1112         /*
1113          * Purge anything not looked at above.
1114          */
1115         Block_Using_Signals(omask);
1116         sepp = &servtab;
1117         while ((sep = *sepp)) {
1118                 if (sep->se_checked) {
1119                         sepp = &sep->se_next;
1120                         continue;
1121                 }
1122                 *sepp = sep->se_next;
1123                 if (sep->se_fd != -1) {
1124                         FD_CLR(sep->se_fd, &allsock);
1125                         nsock--;
1126                         (void) close(sep->se_fd);
1127                 }
1128 #if ENABLE_FEATURE_INETD_RPC
1129                 if (isrpcservice(sep))
1130                         unregister_rpc(sep);
1131 #endif
1132                 if (sep->se_family == AF_UNIX)
1133                         (void) unlink(sep->se_service);
1134                 freeconfig(sep);
1135                 free(sep);
1136         }
1137         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1138 }
1139
1140
1141 static void reapchild(int sig ATTRIBUTE_UNUSED)
1142 {
1143         pid_t pid;
1144         int save_errno = errno, status;
1145         servtab_t *sep;
1146
1147         for (;;) {
1148                 pid = wait3(&status, WNOHANG, NULL);
1149                 if (pid <= 0)
1150                         break;
1151                 for (sep = servtab; sep; sep = sep->se_next)
1152                         if (sep->se_wait == pid) {
1153                                 if (WIFEXITED(status) && WEXITSTATUS(status))
1154                                         bb_error_msg("%s: exit status 0x%x",
1155                                                         sep->se_server, WEXITSTATUS(status));
1156                                 else if (WIFSIGNALED(status))
1157                                         bb_error_msg("%s: exit signal 0x%x",
1158                                                         sep->se_server, WTERMSIG(status));
1159                                 sep->se_wait = 1;
1160                                 FD_SET(sep->se_fd, &allsock);
1161                                 nsock++;
1162                         }
1163         }
1164         errno = save_errno;
1165 }
1166
1167 static void retry(int sig ATTRIBUTE_UNUSED)
1168 {
1169         servtab_t *sep;
1170
1171         timingout = 0;
1172         for (sep = servtab; sep; sep = sep->se_next) {
1173                 if (sep->se_fd == -1) {
1174                         switch (sep->se_family) {
1175                         case AF_UNIX:
1176                         case AF_INET:
1177 #if ENABLE_FEATURE_IPV6
1178                         case AF_INET6:
1179 #endif
1180                                 setup(sep);
1181 #if ENABLE_FEATURE_INETD_RPC
1182                                 if (sep->se_fd != -1 && isrpcservice(sep))
1183                                         register_rpc(sep);
1184 #endif
1185                                 break;
1186                         }
1187                 }
1188         }
1189 }
1190
1191 static void goaway(int sig ATTRIBUTE_UNUSED)
1192 {
1193         servtab_t *sep;
1194
1195         /* XXX signal race walking sep list */
1196         for (sep = servtab; sep; sep = sep->se_next) {
1197                 if (sep->se_fd == -1)
1198                         continue;
1199
1200                 switch (sep->se_family) {
1201                 case AF_UNIX:
1202                         (void) unlink(sep->se_service);
1203                         break;
1204                 case AF_INET:
1205 #if ENABLE_FEATURE_IPV6
1206                 case AF_INET6:
1207 #endif
1208 #if ENABLE_FEATURE_INETD_RPC
1209                         if (sep->se_wait == 1 && isrpcservice(sep))
1210                                 unregister_rpc(sep);   /* XXX signal race */
1211 #endif
1212                         break;
1213                 }
1214                 (void) close(sep->se_fd);
1215         }
1216         remove_pidfile(_PATH_INETDPID);
1217         exit(0);
1218 }
1219
1220
1221 #ifdef INETD_SETPROCTITLE
1222 static char **Argv;
1223 static char *LastArg;
1224
1225 static void
1226 inetd_setproctitle(char *a, int s)
1227 {
1228         socklen_t size;
1229         char *cp;
1230         struct sockaddr_in prt_sin;
1231         char buf[80];
1232
1233         cp = Argv[0];
1234         size = sizeof(prt_sin);
1235         (void) snprintf(buf, sizeof buf, "-%s", a);
1236         if (getpeername(s, (struct sockaddr *) &prt_sin, &size) == 0) {
1237                 char *sa = inet_ntoa(prt_sin.sin_addr);
1238
1239                 buf[sizeof(buf) - 1 - strlen(sa) - 3] = '\0';
1240                 strcat(buf, " [");
1241                 strcat(buf, sa);
1242                 strcat(buf, "]");
1243         }
1244         strncpy(cp, buf, LastArg - cp);
1245         cp += strlen(cp);
1246         while (cp < LastArg)
1247                 *cp++ = ' ';
1248 }
1249 #endif
1250
1251
1252 int inetd_main(int argc, char **argv);
1253 int inetd_main(int argc, char **argv)
1254 {
1255         servtab_t *sep;
1256         struct passwd *pwd;
1257         struct group *grp = NULL;
1258         int tmpint;
1259         struct sigaction sa, sapipe;
1260         int opt;
1261         pid_t pid;
1262         char buf[50];
1263         char *stoomany;
1264         sigset_t omask, wait_mask;
1265
1266 #ifdef INETD_SETPROCTITLE
1267         char **envp = environ;
1268
1269         Argv = argv;
1270         if (envp == 0 || *envp == 0)
1271                 envp = argv;
1272         while (*envp)
1273                 envp++;
1274         LastArg = envp[-1] + strlen(envp[-1]);
1275 #endif
1276
1277         uid = getuid();
1278         if (uid != 0)
1279                 config_filename = NULL;
1280
1281         opt = getopt32(argv, "R:f", &stoomany);
1282         if (opt & 1)
1283                 toomany = xatoi_u(stoomany);
1284         argv += optind;
1285         argc -= optind;
1286         if (argc)
1287                 config_filename = argv[0];
1288         if (config_filename == NULL)
1289                 bb_error_msg_and_die("non-root must specify a config file");
1290
1291         if (!(opt & 2))
1292                 bb_daemonize_or_rexec(0, argv - optind);
1293         else
1294                 bb_sanitize_stdio();
1295         openlog(applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
1296         logmode = LOGMODE_SYSLOG;
1297
1298         if (uid == 0) {
1299                 /* If run by hand, ensure groups vector gets trashed */
1300                 gid_t gid = getgid();
1301                 setgroups(1, &gid);
1302         }
1303
1304         write_pidfile(_PATH_INETDPID);
1305
1306         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
1307                 bb_perror_msg("getrlimit");
1308         } else {
1309                 rlim_ofile_cur = rlim_ofile.rlim_cur;
1310                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
1311                         rlim_ofile_cur = OPEN_MAX;
1312         }
1313
1314         memset((char *) &sa, 0, sizeof(sa));
1315         sigemptyset(&sa.sa_mask);
1316         sigaddset(&sa.sa_mask, SIGALRM);
1317         sigaddset(&sa.sa_mask, SIGCHLD);
1318         sigaddset(&sa.sa_mask, SIGHUP);
1319         sa.sa_handler = retry;
1320         sigaction(SIGALRM, &sa, NULL);
1321         config(SIGHUP);
1322         sa.sa_handler = config;
1323         sigaction(SIGHUP, &sa, NULL);
1324         sa.sa_handler = reapchild;
1325         sigaction(SIGCHLD, &sa, NULL);
1326         sa.sa_handler = goaway;
1327         sigaction(SIGTERM, &sa, NULL);
1328         sa.sa_handler = goaway;
1329         sigaction(SIGINT, &sa, NULL);
1330         sa.sa_handler = SIG_IGN;
1331         sigaction(SIGPIPE, &sa, &sapipe);
1332         memset(&wait_mask, 0, sizeof(wait_mask));
1333         {
1334                 /* space for daemons to overwrite environment for ps */
1335 #define DUMMYSIZE       100
1336                 char dummy[DUMMYSIZE];
1337
1338                 (void) memset(dummy, 'x', DUMMYSIZE - 1);
1339                 dummy[DUMMYSIZE - 1] = '\0';
1340
1341                 (void) setenv("inetd_dummy", dummy, 1);
1342         }
1343
1344         for (;;) {
1345                 int n, ctrl = -1;
1346                 fd_set readable;
1347
1348                 if (nsock == 0) {
1349                         Block_Using_Signals(omask);
1350                         while (nsock == 0)
1351                                 sigsuspend(&wait_mask);
1352                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1353                 }
1354
1355                 readable = allsock;
1356                 n = select(maxsock + 1, &readable, NULL, NULL, NULL);
1357                 if (n <= 0) {
1358                         if (n < 0 && errno != EINTR) {
1359                                 bb_perror_msg("select");
1360                                 sleep(1);
1361                         }
1362                         continue;
1363                 }
1364
1365                 for (sep = servtab; n && sep; sep = sep->se_next) {
1366                         if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1367                                 continue;
1368
1369                         n--;
1370                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
1371                                 ctrl = accept(sep->se_fd, NULL, NULL);
1372                                 if (ctrl < 0) {
1373                                         if (errno == EINTR)
1374                                                 continue;
1375                                         bb_perror_msg("accept (for %s)", sep->se_service);
1376                                         continue;
1377                                 }
1378                                 if (sep->se_family == AF_INET && sep->se_socktype == SOCK_STREAM) {
1379                                         struct sockaddr_in peer;
1380                                         socklen_t plen = sizeof(peer);
1381
1382                                         if (getpeername(ctrl, (struct sockaddr *) &peer, &plen) < 0) {
1383                                                 bb_error_msg("cannot getpeername");
1384                                                 close(ctrl);
1385                                                 continue;
1386                                         }
1387                                         if (ntohs(peer.sin_port) == 20) {
1388                                                 /* XXX ftp bounce */
1389                                                 close(ctrl);
1390                                                 continue;
1391                                         }
1392                                 }
1393                         } else
1394                                 ctrl = sep->se_fd;
1395
1396                         Block_Using_Signals(omask);
1397                         pid = 0;
1398 #ifdef INETD_FEATURE_ENABLED
1399                         if (sep->se_bi == 0 || sep->se_bi->bi_fork)
1400 #endif
1401                         {
1402                                 if (sep->se_count++ == 0)
1403                                         (void) gettimeofday(&sep->se_time, NULL);
1404                                 else if (toomany > 0 && sep->se_count >= sep->se_max) {
1405                                         struct timeval now;
1406
1407                                         (void) gettimeofday(&now, NULL);
1408                                         if (now.tv_sec - sep->se_time.tv_sec > CNT_INTVL) {
1409                                                 sep->se_time = now;
1410                                                 sep->se_count = 1;
1411                                         } else {
1412                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1413                                                         close(ctrl);
1414                                                 if (sep->se_family == AF_INET &&
1415                                                           ntohs(sep->se_ctrladdr_in.sin_port) >= IPPORT_RESERVED) {
1416                                                         /*
1417                                                          * Cannot close it -- there are
1418                                                          * thieves on the system.
1419                                                          * Simply ignore the connection.
1420                                                          */
1421                                                         --sep->se_count;
1422                                                         continue;
1423                                                 }
1424                                                 bb_error_msg("%s/%s server failing (looping), service terminated",
1425                                                               sep->se_service, sep->se_proto);
1426                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1427                                                         close(ctrl);
1428                                                 FD_CLR(sep->se_fd, &allsock);
1429                                                 (void) close(sep->se_fd);
1430                                                 sep->se_fd = -1;
1431                                                 sep->se_count = 0;
1432                                                 nsock--;
1433                                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1434                                                 if (!timingout) {
1435                                                         timingout = 1;
1436                                                         alarm(RETRYTIME);
1437                                                 }
1438                                                 continue;
1439                                         }
1440                                 }
1441                                 pid = fork();
1442                         }
1443                         if (pid < 0) {
1444                                 bb_perror_msg("fork");
1445                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1446                                         close(ctrl);
1447                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1448                                 sleep(1);
1449                                 continue;
1450                         }
1451                         if (pid && sep->se_wait) {
1452                                 sep->se_wait = pid;
1453                                 FD_CLR(sep->se_fd, &allsock);
1454                                 nsock--;
1455                         }
1456                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1457                         if (pid == 0) {
1458 #ifdef INETD_FEATURE_ENABLED
1459                                 if (sep->se_bi) {
1460                                         (*sep->se_bi->bi_fn)(ctrl, sep);
1461                                 } else
1462 #endif
1463                                 {
1464                                         pwd = getpwnam(sep->se_user);
1465                                         if (pwd == NULL) {
1466                                                 bb_error_msg("getpwnam: %s: no such user", sep->se_user);
1467                                                 goto do_exit1;
1468                                         }
1469                                         if (setsid() < 0)
1470                                                 bb_perror_msg("%s: setsid", sep->se_service);
1471                                         if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1472                                                 bb_error_msg("getgrnam: %s: no such group", sep->se_group);
1473                                                 goto do_exit1;
1474                                         }
1475                                         if (uid != 0) {
1476                                                 /* a user running private inetd */
1477                                                 if (uid != pwd->pw_uid)
1478                                                         _exit(1);
1479                                         } else if (pwd->pw_uid) {
1480                                                 if (sep->se_group)
1481                                                         pwd->pw_gid = grp->gr_gid;
1482                                                 xsetgid((gid_t) pwd->pw_gid);
1483                                                 initgroups(pwd->pw_name, pwd->pw_gid);
1484                                                 xsetuid((uid_t) pwd->pw_uid);
1485                                         } else if (sep->se_group) {
1486                                                 xsetgid(grp->gr_gid);
1487                                                 setgroups(1, &grp->gr_gid);
1488                                         }
1489                                         dup2(ctrl, 0);
1490                                         if (ctrl) close(ctrl);
1491                                         dup2(0, 1);
1492                                         dup2(0, 2);
1493                                         if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1494                                                 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1495                                                         bb_perror_msg("setrlimit");
1496                                         closelog();
1497                                         for (tmpint = rlim_ofile_cur - 1; --tmpint > 2;)
1498                                                 (void) close(tmpint);
1499                                         sigaction(SIGPIPE, &sapipe, NULL);
1500                                         execv(sep->se_server, sep->se_argv);
1501                                         bb_perror_msg("execv %s", sep->se_server);
1502  do_exit1:
1503                                         if (sep->se_socktype != SOCK_STREAM)
1504                                                 recv(0, buf, sizeof(buf), 0);
1505                                         _exit(1);
1506                                 }
1507                         }
1508                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1509                                 close(ctrl);
1510                 } /* for (sep = servtab...) */
1511         } /* for (;;) */
1512 }
1513
1514 /*
1515  * Internet services provided internally by inetd:
1516  */
1517 #define BUFSIZE 4096
1518
1519 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
1520         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN || \
1521         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1522 static int dg_badinput(struct sockaddr_in *dg_sin)
1523 {
1524         if (ntohs(dg_sin->sin_port) < IPPORT_RESERVED)
1525                 return 1;
1526         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST))
1527                 return 1;
1528         /* XXX compare against broadcast addresses in SIOCGIFCONF list? */
1529         return 0;
1530 }
1531 #endif
1532
1533 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1534 /* Echo service -- echo data back */
1535 /* ARGSUSED */
1536 static void
1537 echo_stream(int s, servtab_t *sep)
1538 {
1539         char buffer[BUFSIZE];
1540         int i;
1541
1542         inetd_setproctitle(sep->se_service, s);
1543         while (1) {
1544                 i = read(s, buffer, sizeof(buffer));
1545                 if (i <= 0) break;
1546                 /* FIXME: this isnt correct - safe_write()? */
1547                 if (write(s, buffer, i) <= 0) break;
1548         }
1549         exit(0);
1550 }
1551
1552 /* Echo service -- echo data back */
1553 /* ARGSUSED */
1554 static void
1555 echo_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1556 {
1557         char buffer[BUFSIZE];
1558         int i;
1559         socklen_t size;
1560         /* struct sockaddr_storage ss; */
1561         struct sockaddr sa;
1562
1563         size = sizeof(sa);
1564         i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size);
1565         if (i < 0)
1566                 return;
1567         if (dg_badinput((struct sockaddr_in *) &sa))
1568                 return;
1569         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1570 }
1571 #endif  /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1572
1573 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1574 /* Discard service -- ignore data */
1575 /* ARGSUSED */
1576 static void
1577 discard_stream(int s, servtab_t *sep)
1578 {
1579         char buffer[BUFSIZE];
1580
1581         inetd_setproctitle(sep->se_service, s);
1582         while (1) {
1583                 errno = 0;
1584                 if (read(s, buffer, sizeof(buffer)) <= 0 && errno != EINTR)
1585                         exit(0);
1586         }
1587 }
1588
1589 /* Discard service -- ignore data */
1590 /* ARGSUSED */
1591 static void
1592 discard_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1593 {
1594         char buffer[BUFSIZE];
1595
1596         (void) read(s, buffer, sizeof(buffer));
1597 }
1598 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1599
1600
1601 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1602 #define LINESIZ 72
1603 static char ring[128];
1604 static char *endring;
1605
1606 static void
1607 initring(void)
1608 {
1609         int i;
1610
1611         endring = ring;
1612
1613         for (i = 0; i <= 128; ++i)
1614                 if (isprint(i))
1615                         *endring++ = i;
1616 }
1617
1618 /* Character generator */
1619 /* ARGSUSED */
1620 static void
1621 chargen_stream(int s, servtab_t *sep)
1622 {
1623         char *rs;
1624         int len;
1625         char text[LINESIZ + 2];
1626
1627         inetd_setproctitle(sep->se_service, s);
1628
1629         if (!endring) {
1630                 initring();
1631                 rs = ring;
1632         }
1633
1634         text[LINESIZ] = '\r';
1635         text[LINESIZ + 1] = '\n';
1636         rs = ring;
1637         for (;;) {
1638                 len = endring - rs;
1639                 if (len >= LINESIZ)
1640                         memmove(text, rs, LINESIZ);
1641                 else {
1642                         memmove(text, rs, len);
1643                         memmove(text + len, ring, LINESIZ - len);
1644                 }
1645                 if (++rs == endring)
1646                         rs = ring;
1647                 if (write(s, text, sizeof(text)) != sizeof(text))
1648                         break;
1649         }
1650         exit(0);
1651 }
1652
1653 /* Character generator */
1654 /* ARGSUSED */
1655 static void
1656 chargen_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1657 {
1658         /* struct sockaddr_storage ss; */
1659         struct sockaddr sa;
1660         static char *rs;
1661         int len;
1662         char text[LINESIZ + 2];
1663         socklen_t size;
1664
1665         if (endring == 0) {
1666                 initring();
1667                 rs = ring;
1668         }
1669
1670         size = sizeof(sa);
1671         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1672                 return;
1673         if (dg_badinput((struct sockaddr_in *) &sa))
1674                 return;
1675
1676         if ((len = endring - rs) >= LINESIZ)
1677                 memmove(text, rs, LINESIZ);
1678         else {
1679                 memmove(text, rs, len);
1680                 memmove(text + len, ring, LINESIZ - len);
1681         }
1682         if (++rs == endring)
1683                 rs = ring;
1684         text[LINESIZ] = '\r';
1685         text[LINESIZ + 1] = '\n';
1686         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1687 }
1688 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1689
1690
1691 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1692 /*
1693  * Return a machine readable date and time, in the form of the
1694  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1695  * returns the number of seconds since midnight, Jan 1, 1970,
1696  * we must add 2208988800 seconds to this figure to make up for
1697  * some seventy years Bell Labs was asleep.
1698  */
1699
1700 static unsigned machtime(void)
1701 {
1702         struct timeval tv;
1703
1704         if (gettimeofday(&tv, NULL) < 0) {
1705                 fprintf(stderr, "Unable to get time of day\n");
1706                 return 0L;
1707         }
1708         return htonl((unsigned) tv.tv_sec + 2208988800UL);
1709 }
1710
1711 /* ARGSUSED */
1712 static void
1713 machtime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1714 {
1715         unsigned result;
1716
1717         result = machtime();
1718         (void) write(s, (char *) &result, sizeof(result));
1719 }
1720
1721 /* ARGSUSED */
1722 static void
1723 machtime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1724 {
1725         unsigned result;
1726         /* struct sockaddr_storage ss; */
1727         struct sockaddr sa;
1728         struct sockaddr_in *dg_sin;
1729         socklen_t size;
1730
1731         size = sizeof(sa);
1732         if (recvfrom(s, (char *) &result, sizeof(result), 0, &sa, &size) < 0)
1733                 return;
1734         /* if (dg_badinput((struct sockaddr *)&ss)) */
1735         dg_sin = (struct sockaddr_in *) &sa;
1736         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST) ||
1737                         ntohs(dg_sin->sin_port) < IPPORT_RESERVED / 2)
1738                 return;
1739         result = machtime();
1740         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1741 }
1742 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1743
1744
1745 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1746 /* Return human-readable time of day */
1747 /* ARGSUSED */
1748 static void daytime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1749 {
1750         char buffer[32];
1751         time_t t;
1752
1753         t = time(NULL);
1754
1755 // fdprintf instead?
1756         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1757         (void) write(s, buffer, strlen(buffer));
1758 }
1759
1760 /* Return human-readable time of day */
1761 /* ARGSUSED */
1762 void
1763 daytime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1764 {
1765         char buffer[256];
1766         time_t t;
1767         /* struct sockaddr_storage ss; */
1768         struct sockaddr sa;
1769         socklen_t size;
1770
1771         t = time(NULL);
1772
1773         size = sizeof(sa);
1774         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1775                 return;
1776         if (dg_badinput((struct sockaddr_in *) &sa))
1777                 return;
1778         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1779         (void) sendto(s, buffer, strlen(buffer), 0, &sa, sizeof(sa));
1780 }
1781 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */