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         if (setsockopt_reuseaddr(sep->se_fd) < 0)
 457                 bb_perror_msg("setsockopt(SO_REUSEADDR)");
 458
 459 #if ENABLE_FEATURE_INETD_RPC
 460         if (isrpcservice(sep)) {
 461                 struct passwd *pwd;
 462
 463                 /*
 464                  * for RPC services, attempt to use a reserved port
 465                  * if they are going to be running as root.
 466                  *
 467                  * Also, zero out the port for all RPC services; let bind()
 468                  * find one.
 469                  */
 470                 sep->se_ctrladdr_in.sin_port = 0;
 471                 if (sep->se_user && (pwd = getpwnam(sep->se_user)) &&
 472                                 pwd->pw_uid == 0 && uid == 0)
 473                         r = bindresvport(sep->se_fd, &sep->se_ctrladdr_in);
 474                 else {
 475                         r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 476                         if (r == 0) {
 477                                 socklen_t len = sep->se_ctrladdr_size;
 478                                 int saveerrno = errno;
 479
 480                                 /* update se_ctrladdr_in.sin_port */
 481                                 r = getsockname(sep->se_fd, &sep->se_ctrladdr, &len);
 482                                 if (r <= 0)
 483                                         errno = saveerrno;
 484                         }
 485                 }
 486         } else
 487 #endif
 488                 r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 489         if (r < 0) {
 490                 bb_perror_msg("%s/%s (%d): bind",
 491                                 sep->se_service, sep->se_proto, sep->se_ctrladdr.sa_family);
 492                 close(sep->se_fd);
 493                 sep->se_fd = -1;
 494                 if (!timingout) {
 495                         timingout = 1;
 496                         alarm(RETRYTIME);
 497                 }
 498                 return;
 499         }
 500         if (sep->se_socktype == SOCK_STREAM)
 501                 listen(sep->se_fd, global_queuelen);
 502
 503         FD_SET(sep->se_fd, &allsock);
 504         nsock++;
 505         if (sep->se_fd > maxsock) {
 506                 maxsock = sep->se_fd;
 507                 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
 508                         bump_nofile();
 509         }
 510 }
 511
 512 static char *nextline(void)
 513 {
 514 #define line bb_common_bufsiz1
 515
 516         char *cp;
 517         FILE *fd = fconfig;
 518
 519         if (fgets(line, sizeof(line), fd) == NULL)
 520                 return NULL;
 521         cp = strchr(line, '\n');
 522         if (cp)
 523                 *cp = '\0';
 524         return line;
 525 }
 526
 527 static char *skip(char **cpp) /* int report; */
 528 {
 529         char *cp = *cpp;
 530         char *start;
 531
 532 /* erp: */
 533         if (*cpp == NULL) {
 534                 /* if (report) */
 535                 /* bb_error_msg("syntax error in inetd config file"); */
 536                 return NULL;
 537         }
 538
 539  again:
 540         while (*cp == ' ' || *cp == '\t')
 541                 cp++;
 542         if (*cp == '\0') {
 543                 int c;
 544
 545                 c = getc(fconfig);
 546                 ungetc(c, fconfig);
 547                 if (c == ' ' || c == '\t') {
 548                         cp = nextline();
 549                         if (cp)
 550                                 goto again;
 551                 }
 552                 *cpp = NULL;
 553                 /* goto erp; */
 554                 return NULL;
 555         }
 556         start = cp;
 557         while (*cp && *cp != ' ' && *cp != '\t')
 558                 cp++;
 559         if (*cp != '\0')
 560                 *cp++ = '\0';
 561         /* if ((*cpp = cp) == NULL) */
 562         /* goto erp; */
 563
 564         *cpp = cp;
 565         return start;
 566 }
 567
 568 static servtab_t *new_servtab(void)
 569 {
 570         return xmalloc(sizeof(servtab_t));
 571 }
 572
 573 static servtab_t *dupconfig(servtab_t *sep)
 574 {
 575         servtab_t *newtab;
 576         int argc;
 577
 578         newtab = new_servtab();
 579         memset(newtab, 0, sizeof(servtab_t));
 580         newtab->se_service = xstrdup(sep->se_service);
 581         newtab->se_socktype = sep->se_socktype;
 582         newtab->se_family = sep->se_family;
 583         newtab->se_proto = xstrdup(sep->se_proto);
 584 #if ENABLE_FEATURE_INETD_RPC
 585         newtab->se_rpcprog = sep->se_rpcprog;
 586         newtab->se_rpcversl = sep->se_rpcversl;
 587         newtab->se_rpcversh = sep->se_rpcversh;
 588 #endif
 589         newtab->se_wait = sep->se_wait;
 590         newtab->se_user = xstrdup(sep->se_user);
 591         newtab->se_group = xstrdup(sep->se_group);
 592 #ifdef INETD_FEATURE_ENABLED
 593         newtab->se_bi = sep->se_bi;
 594 #endif
 595         newtab->se_server = xstrdup(sep->se_server);
 596
 597         for (argc = 0; argc <= MAXARGV; argc++)
 598                 newtab->se_argv[argc] = xstrdup(sep->se_argv[argc]);
 599         newtab->se_max = sep->se_max;
 600
 601         return newtab;
 602 }
 603
 604 static servtab_t *getconfigent(void)
 605 {
 606         servtab_t *sep;
 607         int argc;
 608         char *cp, *arg;
 609         char *hostdelim;
 610         servtab_t *nsep;
 611         servtab_t *psep;
 612
 613         sep = new_servtab();
 614
 615         /* memset(sep, 0, sizeof *sep); */
 616  more:
 617         /* freeconfig(sep); */
 618
 619         while ((cp = nextline()) && *cp == '#') /* skip comment line */;
 620         if (cp == NULL) {
 621                 /* free(sep); */
 622                 return NULL;
 623         }
 624
 625         memset((char *) sep, 0, sizeof *sep);
 626         arg = skip(&cp);
 627         if (arg == NULL) {
 628                 /* A blank line. */
 629                 goto more;
 630         }
 631
 632         /* Check for a host name. */
 633         hostdelim = strrchr(arg, ':');
 634         if (hostdelim) {
 635                 *hostdelim = '\0';
 636                 sep->se_hostaddr = xstrdup(arg);
 637                 arg = hostdelim + 1;
 638                 /*
 639                  * If the line is of the form `host:', then just change the
 640                  * default host for the following lines.
 641                  */
 642                 if (*arg == '\0') {
 643                         arg = skip(&cp);
 644                         if (cp == NULL) {
 645                                 free(defhost);
 646                                 defhost = sep->se_hostaddr;
 647                                 goto more;
 648                         }
 649                 }
 650         } else
 651                 sep->se_hostaddr = xxstrdup(defhost);
 652
 653         sep->se_service = xxstrdup(arg);
 654         arg = skip(&cp);
 655
 656         if (strcmp(arg, "stream") == 0)
 657                 sep->se_socktype = SOCK_STREAM;
 658         else if (strcmp(arg, "dgram") == 0)
 659                 sep->se_socktype = SOCK_DGRAM;
 660         else if (strcmp(arg, "rdm") == 0)
 661                 sep->se_socktype = SOCK_RDM;
 662         else if (strcmp(arg, "seqpacket") == 0)
 663                 sep->se_socktype = SOCK_SEQPACKET;
 664         else if (strcmp(arg, "raw") == 0)
 665                 sep->se_socktype = SOCK_RAW;
 666         else
 667                 sep->se_socktype = -1;
 668
 669         sep->se_proto = xxstrdup(skip(&cp));
 670
 671         if (strcmp(sep->se_proto, "unix") == 0) {
 672                 sep->se_family = AF_UNIX;
 673         } else {
 674                 sep->se_family = AF_INET;
 675                 if (sep->se_proto[strlen(sep->se_proto) - 1] == '6')
 676 #if ENABLE_FEATURE_IPV6
 677                         sep->se_family = AF_INET6;
 678 #else
 679                         bb_error_msg("%s: IPV6 not supported", sep->se_proto);
 680 #endif
 681                 if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
 682 #if ENABLE_FEATURE_INETD_RPC
 683                         char *p, *ccp;
 684                         long l;
 685
 686                         p = strchr(sep->se_service, '/');
 687                         if (p == 0) {
 688                                 bb_error_msg("%s: no rpc version", sep->se_service);
 689                                 goto more;
 690                         }
 691                         *p++ = '\0';
 692                         l = strtol(p, &ccp, 0);
 693                         if (ccp == p || l < 0 || l > INT_MAX) {
 694  badafterall:
 695                                 bb_error_msg("%s/%s: bad rpc version", sep->se_service, p);
 696                                 goto more;
 697                         }
 698                         sep->se_rpcversl = sep->se_rpcversh = l;
 699                         if (*ccp == '-') {
 700                                 p = ccp + 1;
 701                                 l = strtol(p, &ccp, 0);
 702                                 if (ccp == p || l < 0 || l > INT_MAX || l < sep->se_rpcversl || *ccp)
 703                                         goto badafterall;
 704                                 sep->se_rpcversh = l;
 705                         } else if (*ccp != '\0')
 706                                 goto badafterall;
 707 #else
 708                         bb_error_msg("%s: rpc services not supported", sep->se_service);
 709 #endif
 710                 }
 711         }
 712         arg = skip(&cp);
 713         if (arg == NULL)
 714                 goto more;
 715
 716         {
 717                 char *s = strchr(arg, '.');
 718                 if (s) {
 719                         *s++ = '\0';
 720                         sep->se_max = xatoi(s);
 721                 } else
 722                         sep->se_max = toomany;
 723         }
 724         sep->se_wait = strcmp(arg, "wait") == 0;
 725         /* if ((arg = skip(&cp, 1)) == NULL) */
 726         /* goto more; */
 727         sep->se_user = xxstrdup(skip(&cp));
 728         arg = strchr(sep->se_user, '.');
 729         if (arg == NULL)
 730                 arg = strchr(sep->se_user, ':');
 731         if (arg) {
 732                 *arg++ = '\0';
 733                 sep->se_group = xstrdup(arg);
 734         }
 735         /* if ((arg = skip(&cp, 1)) == NULL) */
 736         /* goto more; */
 737
 738         sep->se_server = xxstrdup(skip(&cp));
 739         if (strcmp(sep->se_server, "internal") == 0) {
 740 #ifdef INETD_FEATURE_ENABLED
 741                 const struct builtin *bi;
 742
 743                 for (bi = builtins; bi->bi_service; bi++)
 744                         if (bi->bi_socktype == sep->se_socktype &&
 745                                         strcmp(bi->bi_service, sep->se_service) == 0)
 746                                 break;
 747                 if (bi->bi_service == 0) {
 748                         bb_error_msg("internal service %s unknown", sep->se_service);
 749                         goto more;
 750                 }
 751                 sep->se_bi = bi;
 752                 sep->se_wait = bi->bi_wait;
 753 #else
 754                 bb_perror_msg("internal service %s unknown", sep->se_service);
 755                 goto more;
 756 #endif
 757         }
 758 #ifdef INETD_FEATURE_ENABLED
 759                 else
 760                 sep->se_bi = NULL;
 761 #endif
 762         argc = 0;
 763         for (arg = skip(&cp); cp; arg = skip(&cp)) {
 764                 if (argc < MAXARGV)
 765                         sep->se_argv[argc++] = xxstrdup(arg);
 766         }
 767         while (argc <= MAXARGV)
 768                 sep->se_argv[argc++] = NULL;
 769
 770         /*
 771          * Now that we've processed the entire line, check if the hostname
 772          * specifier was a comma separated list of hostnames. If so
 773          * we'll make new entries for each address.
 774          */
 775         while ((hostdelim = strrchr(sep->se_hostaddr, ',')) != NULL) {
 776                 nsep = dupconfig(sep);
 777
 778                 /*
 779                  * NULL terminate the hostname field of the existing entry,
 780                  * and make a dup for the new entry.
 781                  */
 782                 *hostdelim++ = '\0';
 783                 nsep->se_hostaddr = xstrdup(hostdelim);
 784
 785                 nsep->se_next = sep->se_next;
 786                 sep->se_next = nsep;
 787         }
 788
 789         nsep = sep;
 790         while (nsep != NULL) {
 791                 nsep->se_checked = 1;
 792                 if (nsep->se_family == AF_INET) {
 793                         if (LONE_CHAR(nsep->se_hostaddr, '*'))
 794                                 nsep->se_ctrladdr_in.sin_addr.s_addr = INADDR_ANY;
 795                         else if (!inet_aton(nsep->se_hostaddr, &nsep->se_ctrladdr_in.sin_addr)) {
 796                                 struct hostent *hp;
 797
 798                                 hp = gethostbyname(nsep->se_hostaddr);
 799                                 if (hp == 0) {
 800                                         bb_error_msg("%s: unknown host", nsep->se_hostaddr);
 801                                         nsep->se_checked = 0;
 802                                         goto skip;
 803                                 } else if (hp->h_addrtype != AF_INET) {
 804                                         bb_error_msg("%s: address isn't an Internet "
 805                                                                   "address", nsep->se_hostaddr);
 806                                         nsep->se_checked = 0;
 807                                         goto skip;
 808                                 } else {
 809                                         int i = 1;
 810
 811                                         memmove(&nsep->se_ctrladdr_in.sin_addr,
 812                                                                    hp->h_addr_list[0], sizeof(struct in_addr));
 813                                         while (hp->h_addr_list[i] != NULL) {
 814                                                 psep = dupconfig(nsep);
 815                                                 psep->se_hostaddr = xxstrdup(nsep->se_hostaddr);
 816                                                 psep->se_checked = 1;
 817                                                 memmove(&psep->se_ctrladdr_in.sin_addr,
 818                                                                      hp->h_addr_list[i], sizeof(struct in_addr));
 819                                                 psep->se_ctrladdr_size = sizeof(psep->se_ctrladdr_in);
 820                                                 i++;
 821                                                 /* Prepend to list, don't want to look up */
 822                                                 /* its hostname again. */
 823                                                 psep->se_next = sep;
 824                                                 sep = psep;
 825                                         }
 826                                 }
 827                         }
 828                 }
 829 /* XXX BUG?: is this skip: label supposed to remain? */
 830  skip:
 831                 nsep = nsep->se_next;
 832         }
 833
 834         /*
 835          * Finally, free any entries which failed the gethostbyname
 836          * check.
 837          */
 838         psep = NULL;
 839         nsep = sep;
 840         while (nsep != NULL) {
 841                 servtab_t *tsep;
 842
 843                 if (nsep->se_checked == 0) {
 844                         tsep = nsep;
 845                         if (psep == NULL) {
 846                                 sep = nsep->se_next;
 847                                 nsep = sep;
 848                         } else {
 849                                 nsep = nsep->se_next;
 850                                 psep->se_next = nsep;
 851                         }
 852                         freeconfig(tsep);
 853                 } else {
 854                         nsep->se_checked = 0;
 855                         psep = nsep;
 856                         nsep = nsep->se_next;
 857                 }
 858         }
 859
 860         return sep;
 861 }
 862
 863 #define Block_Using_Signals(m) do { \
 864         sigemptyset(&m); \
 865         sigaddset(&m, SIGCHLD); \
 866         sigaddset(&m, SIGHUP); \
 867         sigaddset(&m, SIGALRM); \
 868         sigprocmask(SIG_BLOCK, &m, NULL); \
 869 } while (0)
 870
 871 static servtab_t *enter(servtab_t *cp)
 872 {
 873         servtab_t *sep;
 874         sigset_t omask;
 875
 876         sep = new_servtab();
 877         *sep = *cp;
 878         sep->se_fd = -1;
 879 #if ENABLE_FEATURE_INETD_RPC
 880         sep->se_rpcprog = -1;
 881 #endif
 882         Block_Using_Signals(omask);
 883         sep->se_next = servtab;
 884         servtab = sep;
 885         sigprocmask(SIG_UNBLOCK, &omask, NULL);
 886         return sep;
 887 }
 888
 889 static int matchconf(servtab_t *old, servtab_t *new)
 890 {
 891         if (strcmp(old->se_service, new->se_service) != 0)
 892                 return 0;
 893
 894         if (strcmp(old->se_hostaddr, new->se_hostaddr) != 0)
 895                 return 0;
 896
 897         if (strcmp(old->se_proto, new->se_proto) != 0)
 898                 return 0;
 899
 900         /*
 901          * If the new servtab is bound to a specific address, check that the
 902          * old servtab is bound to the same entry. If the new service is not
 903          * bound to a specific address then the check of se_hostaddr above
 904          * is sufficient.
 905          */
 906
 907         if (old->se_family == AF_INET && new->se_family == AF_INET &&
 908                         memcmp(&old->se_ctrladdr_in.sin_addr,
 909                                         &new->se_ctrladdr_in.sin_addr,
 910                                         sizeof(new->se_ctrladdr_in.sin_addr)) != 0)
 911                 return 0;
 912
 913 #if ENABLE_FEATURE_IPV6
 914         if (old->se_family == AF_INET6 && new->se_family == AF_INET6 &&
 915                         memcmp(&old->se_ctrladdr_in6.sin6_addr,
 916                                         &new->se_ctrladdr_in6.sin6_addr,
 917                                         sizeof(new->se_ctrladdr_in6.sin6_addr)) != 0)
 918                 return 0;
 919 #endif
 920         return 1;
 921 }
 922
 923 static void config(int sig ATTRIBUTE_UNUSED)
 924 {
 925         servtab_t *sep, *cp, **sepp;
 926         sigset_t omask;
 927         size_t n;
 928         char protoname[10];
 929
 930         if (!setconfig()) {
 931                 bb_perror_msg("%s", config_filename);
 932                 return;
 933         }
 934         for (sep = servtab; sep; sep = sep->se_next)
 935                 sep->se_checked = 0;
 936         cp = getconfigent();
 937         while (cp != NULL) {
 938                 for (sep = servtab; sep; sep = sep->se_next)
 939                         if (matchconf(sep, cp))
 940                                 break;
 941
 942                 if (sep != 0) {
 943                         int i;
 944
 945 #define SWAP(type, a, b) do {type c=(type)a; a=(type)b; b=(type)c;} while (0)
 946
 947                         Block_Using_Signals(omask);
 948                         /*
 949                          * sep->se_wait may be holding the pid of a daemon
 950                          * that we're waiting for.  If so, don't overwrite
 951                          * it unless the config file explicitly says don't
 952                          * wait.
 953                          */
 954                         if (
 955 #ifdef INETD_FEATURE_ENABLED
 956                                 cp->se_bi == 0 &&
 957 #endif
 958                                 (sep->se_wait == 1 || cp->se_wait == 0))
 959                                 sep->se_wait = cp->se_wait;
 960                         SWAP(int, cp->se_max, sep->se_max);
 961                         SWAP(char *, sep->se_user, cp->se_user);
 962                         SWAP(char *, sep->se_group, cp->se_group);
 963                         SWAP(char *, sep->se_server, cp->se_server);
 964                         for (i = 0; i < MAXARGV; i++)
 965                                 SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
 966 #undef SWAP
 967
 968 #if ENABLE_FEATURE_INETD_RPC
 969                         if (isrpcservice(sep))
 970                                 unregister_rpc(sep);
 971                         sep->se_rpcversl = cp->se_rpcversl;
 972                         sep->se_rpcversh = cp->se_rpcversh;
 973 #endif
 974                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
 975                         freeconfig(cp);
 976                 } else {
 977                         sep = enter(cp);
 978                 }
 979                 sep->se_checked = 1;
 980
 981                 switch (sep->se_family) {
 982                 case AF_UNIX:
 983                         if (sep->se_fd != -1)
 984                                 break;
 985                         (void) unlink(sep->se_service);
 986                         n = strlen(sep->se_service);
 987                         if (n > sizeof sep->se_ctrladdr_un.sun_path - 1)
 988                                 n = sizeof sep->se_ctrladdr_un.sun_path - 1;
 989                         safe_strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n + 1);
 990                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
 991                         sep->se_ctrladdr_size = n + sizeof sep->se_ctrladdr_un.sun_family;
 992                         setup(sep);
 993                         break;
 994                 case AF_INET:
 995                         sep->se_ctrladdr_in.sin_family = AF_INET;
 996                         /* se_ctrladdr_in was set in getconfigent */
 997                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
 998
 999 #if ENABLE_FEATURE_INETD_RPC
1000                         if (isrpcservice(sep)) {
1001                                 struct rpcent *rp;
1002                                 // FIXME: atoi_or_else(str, 0) would be handy here
1003                                 sep->se_rpcprog = atoi(sep->se_service);
1004                                 if (sep->se_rpcprog == 0) {
1005                                         rp = getrpcbyname(sep->se_service);
1006                                         if (rp == 0) {
1007                                                 bb_error_msg("%s: unknown rpc service", sep->se_service);
1008                                                 goto serv_unknown;
1009                                         }
1010                                         sep->se_rpcprog = rp->r_number;
1011                                 }
1012                                 if (sep->se_fd == -1)
1013                                         setup(sep);
1014                                 if (sep->se_fd != -1)
1015                                         register_rpc(sep);
1016                         } else
1017 #endif
1018                         {
1019                                 uint16_t port = htons(atoi(sep->se_service));
1020                                 // FIXME: atoi_or_else(str, 0) would be handy here
1021                                 if (!port) {
1022                                          /*XXX*/ strncpy(protoname, sep->se_proto, sizeof(protoname));
1023                                         if (isdigit(protoname[strlen(protoname) - 1]))
1024                                                 protoname[strlen(protoname) - 1] = '\0';
1025                                         sp = getservbyname(sep->se_service, protoname);
1026                                         if (sp == 0) {
1027                                                 bb_error_msg("%s/%s: unknown service",
1028                                                                 sep->se_service, sep->se_proto);
1029                                                 goto serv_unknown;
1030                                         }
1031                                         port = sp->s_port;
1032                                 }
1033                                 if (port != sep->se_ctrladdr_in.sin_port) {
1034                                         sep->se_ctrladdr_in.sin_port = port;
1035                                         if (sep->se_fd != -1) {
1036                                                 FD_CLR(sep->se_fd, &allsock);
1037                                                 nsock--;
1038                                                 (void) close(sep->se_fd);
1039                                         }
1040                                         sep->se_fd = -1;
1041                                 }
1042                                 if (sep->se_fd == -1)
1043                                         setup(sep);
1044                         }
1045                         break;
1046 #if ENABLE_FEATURE_IPV6
1047                 case AF_INET6:
1048                         sep->se_ctrladdr_in6.sin6_family = AF_INET6;
1049                         /* se_ctrladdr_in was set in getconfigent */
1050                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in6;
1051
1052 #if ENABLE_FEATURE_INETD_RPC
1053                         if (isrpcservice(sep)) {
1054                                 struct rpcent *rp;
1055
1056                                 sep->se_rpcprog = atoi(sep->se_service);
1057                                 if (sep->se_rpcprog == 0) {
1058                                         rp = getrpcbyname(sep->se_service);
1059                                         if (rp == 0) {
1060                                                 bb_error_msg("%s: unknown rpc service", sep->se_service);
1061                                                 goto serv_unknown;
1062                                         }
1063                                         sep->se_rpcprog = rp->r_number;
1064                                 }
1065                                 if (sep->se_fd == -1)
1066                                         setup(sep);
1067                                 if (sep->se_fd != -1)
1068                                         register_rpc(sep);
1069                         } else
1070 #endif
1071                         {
1072                                 uint16_t port = htons(atoi(sep->se_service));
1073
1074                                 if (!port) {
1075                                          /*XXX*/ strncpy(protoname, sep->se_proto, sizeof(protoname));
1076                                         if (isdigit(protoname[strlen(protoname) - 1]))
1077                                                 protoname[strlen(protoname) - 1] = '\0';
1078                                         sp = getservbyname(sep->se_service, protoname);
1079                                         if (sp == 0) {
1080                                                 bb_error_msg("%s/%s: unknown service",
1081                                                                 sep->se_service, sep->se_proto);
1082                                                 goto serv_unknown;
1083                                         }
1084                                         port = sp->s_port;
1085                                 }
1086                                 if (port != sep->se_ctrladdr_in6.sin6_port) {
1087                                         sep->se_ctrladdr_in6.sin6_port = port;
1088                                         if (sep->se_fd != -1) {
1089                                                 FD_CLR(sep->se_fd, &allsock);
1090                                                 nsock--;
1091                                                 (void) close(sep->se_fd);
1092                                         }
1093                                         sep->se_fd = -1;
1094                                 }
1095                                 if (sep->se_fd == -1)
1096                                         setup(sep);
1097                         }
1098                         break;
1099 #endif /* FEATURE_IPV6 */
1100                 }
1101  serv_unknown:
1102                 if (cp->se_next != NULL) {
1103                         servtab_t *tmp = cp;
1104
1105                         cp = cp->se_next;
1106                         free(tmp);
1107                 } else {
1108                         free(cp);
1109                         cp = getconfigent();
1110                 }
1111         }
1112         endconfig();
1113         /*
1114          * Purge anything not looked at above.
1115          */
1116         Block_Using_Signals(omask);
1117         sepp = &servtab;
1118         while ((sep = *sepp)) {
1119                 if (sep->se_checked) {
1120                         sepp = &sep->se_next;
1121                         continue;
1122                 }
1123                 *sepp = sep->se_next;
1124                 if (sep->se_fd != -1) {
1125                         FD_CLR(sep->se_fd, &allsock);
1126                         nsock--;
1127                         (void) close(sep->se_fd);
1128                 }
1129 #if ENABLE_FEATURE_INETD_RPC
1130                 if (isrpcservice(sep))
1131                         unregister_rpc(sep);
1132 #endif
1133                 if (sep->se_family == AF_UNIX)
1134                         (void) unlink(sep->se_service);
1135                 freeconfig(sep);
1136                 free(sep);
1137         }
1138         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1139 }
1140
1141
1142 static void reapchild(int sig ATTRIBUTE_UNUSED)
1143 {
1144         pid_t pid;
1145         int save_errno = errno, status;
1146         servtab_t *sep;
1147
1148         for (;;) {
1149                 pid = wait3(&status, WNOHANG, NULL);
1150                 if (pid <= 0)
1151                         break;
1152                 for (sep = servtab; sep; sep = sep->se_next)
1153                         if (sep->se_wait == pid) {
1154                                 if (WIFEXITED(status) && WEXITSTATUS(status))
1155                                         bb_error_msg("%s: exit status 0x%x",
1156                                                         sep->se_server, WEXITSTATUS(status));
1157                                 else if (WIFSIGNALED(status))
1158                                         bb_error_msg("%s: exit signal 0x%x",
1159                                                         sep->se_server, WTERMSIG(status));
1160                                 sep->se_wait = 1;
1161                                 FD_SET(sep->se_fd, &allsock);
1162                                 nsock++;
1163                         }
1164         }
1165         errno = save_errno;
1166 }
1167
1168 static void retry(int sig ATTRIBUTE_UNUSED)
1169 {
1170         servtab_t *sep;
1171
1172         timingout = 0;
1173         for (sep = servtab; sep; sep = sep->se_next) {
1174                 if (sep->se_fd == -1) {
1175                         switch (sep->se_family) {
1176                         case AF_UNIX:
1177                         case AF_INET:
1178 #if ENABLE_FEATURE_IPV6
1179                         case AF_INET6:
1180 #endif
1181                                 setup(sep);
1182 #if ENABLE_FEATURE_INETD_RPC
1183                                 if (sep->se_fd != -1 && isrpcservice(sep))
1184                                         register_rpc(sep);
1185 #endif
1186                                 break;
1187                         }
1188                 }
1189         }
1190 }
1191
1192 static void goaway(int sig ATTRIBUTE_UNUSED)
1193 {
1194         servtab_t *sep;
1195
1196         /* XXX signal race walking sep list */
1197         for (sep = servtab; sep; sep = sep->se_next) {
1198                 if (sep->se_fd == -1)
1199                         continue;
1200
1201                 switch (sep->se_family) {
1202                 case AF_UNIX:
1203                         (void) unlink(sep->se_service);
1204                         break;
1205                 case AF_INET:
1206 #if ENABLE_FEATURE_IPV6
1207                 case AF_INET6:
1208 #endif
1209 #if ENABLE_FEATURE_INETD_RPC
1210                         if (sep->se_wait == 1 && isrpcservice(sep))
1211                                 unregister_rpc(sep);   /* XXX signal race */
1212 #endif
1213                         break;
1214                 }
1215                 (void) close(sep->se_fd);
1216         }
1217         remove_pidfile(_PATH_INETDPID);
1218         exit(0);
1219 }
1220
1221
1222 #ifdef INETD_SETPROCTITLE
1223 static char **Argv;
1224 static char *LastArg;
1225
1226 static void
1227 inetd_setproctitle(char *a, int s)
1228 {
1229         socklen_t size;
1230         char *cp;
1231         struct sockaddr_in prt_sin;
1232         char buf[80];
1233
1234         cp = Argv[0];
1235         size = sizeof(prt_sin);
1236         (void) snprintf(buf, sizeof buf, "-%s", a);
1237         if (getpeername(s, (struct sockaddr *) &prt_sin, &size) == 0) {
1238                 char *sa = inet_ntoa(prt_sin.sin_addr);
1239
1240                 buf[sizeof(buf) - 1 - strlen(sa) - 3] = '\0';
1241                 strcat(buf, " [");
1242                 strcat(buf, sa);
1243                 strcat(buf, "]");
1244         }
1245         strncpy(cp, buf, LastArg - cp);
1246         cp += strlen(cp);
1247         while (cp < LastArg)
1248                 *cp++ = ' ';
1249 }
1250 #endif
1251
1252
1253 int inetd_main(int argc, char **argv);
1254 int inetd_main(int argc, char **argv)
1255 {
1256         servtab_t *sep;
1257         struct passwd *pwd;
1258         struct group *grp = NULL;
1259         int tmpint;
1260         struct sigaction sa, sapipe;
1261         int opt;
1262         pid_t pid;
1263         char buf[50];
1264         char *stoomany;
1265         sigset_t omask, wait_mask;
1266
1267 #ifdef INETD_SETPROCTITLE
1268         char **envp = environ;
1269
1270         Argv = argv;
1271         if (envp == 0 || *envp == 0)
1272                 envp = argv;
1273         while (*envp)
1274                 envp++;
1275         LastArg = envp[-1] + strlen(envp[-1]);
1276 #endif
1277
1278         uid = getuid();
1279         if (uid != 0)
1280                 config_filename = NULL;
1281
1282         opt = getopt32(argc, argv, "R:f", &stoomany);
1283         if (opt & 1)
1284                 toomany = xatoi_u(stoomany);
1285         argv += optind;
1286         argc -= optind;
1287         if (argc)
1288                 config_filename = argv[0];
1289         if (config_filename == NULL)
1290                 bb_error_msg_and_die("non-root must specify a config file");
1291
1292         if (!(opt & 2))
1293                 bb_daemonize_or_rexec(0, argv - optind);
1294         else
1295                 bb_sanitize_stdio();
1296         openlog(applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
1297         logmode = LOGMODE_SYSLOG;
1298
1299         if (uid == 0) {
1300                 /* If run by hand, ensure groups vector gets trashed */
1301                 gid_t gid = getgid();
1302                 setgroups(1, &gid);
1303         }
1304
1305         write_pidfile(_PATH_INETDPID);
1306
1307         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
1308                 bb_perror_msg("getrlimit");
1309         } else {
1310                 rlim_ofile_cur = rlim_ofile.rlim_cur;
1311                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
1312                         rlim_ofile_cur = OPEN_MAX;
1313         }
1314
1315         memset((char *) &sa, 0, sizeof(sa));
1316         sigemptyset(&sa.sa_mask);
1317         sigaddset(&sa.sa_mask, SIGALRM);
1318         sigaddset(&sa.sa_mask, SIGCHLD);
1319         sigaddset(&sa.sa_mask, SIGHUP);
1320         sa.sa_handler = retry;
1321         sigaction(SIGALRM, &sa, NULL);
1322         config(SIGHUP);
1323         sa.sa_handler = config;
1324         sigaction(SIGHUP, &sa, NULL);
1325         sa.sa_handler = reapchild;
1326         sigaction(SIGCHLD, &sa, NULL);
1327         sa.sa_handler = goaway;
1328         sigaction(SIGTERM, &sa, NULL);
1329         sa.sa_handler = goaway;
1330         sigaction(SIGINT, &sa, NULL);
1331         sa.sa_handler = SIG_IGN;
1332         sigaction(SIGPIPE, &sa, &sapipe);
1333         memset(&wait_mask, 0, sizeof(wait_mask));
1334         {
1335                 /* space for daemons to overwrite environment for ps */
1336 #define DUMMYSIZE       100
1337                 char dummy[DUMMYSIZE];
1338
1339                 (void) memset(dummy, 'x', DUMMYSIZE - 1);
1340                 dummy[DUMMYSIZE - 1] = '\0';
1341
1342                 (void) setenv("inetd_dummy", dummy, 1);
1343         }
1344
1345         for (;;) {
1346                 int n, ctrl = -1;
1347                 fd_set readable;
1348
1349                 if (nsock == 0) {
1350                         Block_Using_Signals(omask);
1351                         while (nsock == 0)
1352                                 sigsuspend(&wait_mask);
1353                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1354                 }
1355
1356                 readable = allsock;
1357                 n = select(maxsock + 1, &readable, NULL, NULL, NULL);
1358                 if (n <= 0) {
1359                         if (n < 0 && errno != EINTR) {
1360                                 bb_perror_msg("select");
1361                                 sleep(1);
1362                         }
1363                         continue;
1364                 }
1365
1366                 for (sep = servtab; n && sep; sep = sep->se_next) {
1367                         if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1368                                 continue;
1369
1370                         n--;
1371                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
1372                                 ctrl = accept(sep->se_fd, NULL, NULL);
1373                                 if (ctrl < 0) {
1374                                         if (errno == EINTR)
1375                                                 continue;
1376                                         bb_perror_msg("accept (for %s)", sep->se_service);
1377                                         continue;
1378                                 }
1379                                 if (sep->se_family == AF_INET && sep->se_socktype == SOCK_STREAM) {
1380                                         struct sockaddr_in peer;
1381                                         socklen_t plen = sizeof(peer);
1382
1383                                         if (getpeername(ctrl, (struct sockaddr *) &peer, &plen) < 0) {
1384                                                 bb_error_msg("cannot getpeername");
1385                                                 close(ctrl);
1386                                                 continue;
1387                                         }
1388                                         if (ntohs(peer.sin_port) == 20) {
1389                                                 /* XXX ftp bounce */
1390                                                 close(ctrl);
1391                                                 continue;
1392                                         }
1393                                 }
1394                         } else
1395                                 ctrl = sep->se_fd;
1396
1397                         Block_Using_Signals(omask);
1398                         pid = 0;
1399 #ifdef INETD_FEATURE_ENABLED
1400                         if (sep->se_bi == 0 || sep->se_bi->bi_fork)
1401 #endif
1402                         {
1403                                 if (sep->se_count++ == 0)
1404                                         (void) gettimeofday(&sep->se_time, NULL);
1405                                 else if (toomany > 0 && sep->se_count >= sep->se_max) {
1406                                         struct timeval now;
1407
1408                                         (void) gettimeofday(&now, NULL);
1409                                         if (now.tv_sec - sep->se_time.tv_sec > CNT_INTVL) {
1410                                                 sep->se_time = now;
1411                                                 sep->se_count = 1;
1412                                         } else {
1413                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1414                                                         close(ctrl);
1415                                                 if (sep->se_family == AF_INET &&
1416                                                           ntohs(sep->se_ctrladdr_in.sin_port) >= IPPORT_RESERVED) {
1417                                                         /*
1418                                                          * Cannot close it -- there are
1419                                                          * thieves on the system.
1420                                                          * Simply ignore the connection.
1421                                                          */
1422                                                         --sep->se_count;
1423                                                         continue;
1424                                                 }
1425                                                 bb_error_msg("%s/%s server failing (looping), service terminated",
1426                                                               sep->se_service, sep->se_proto);
1427                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1428                                                         close(ctrl);
1429                                                 FD_CLR(sep->se_fd, &allsock);
1430                                                 (void) close(sep->se_fd);
1431                                                 sep->se_fd = -1;
1432                                                 sep->se_count = 0;
1433                                                 nsock--;
1434                                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1435                                                 if (!timingout) {
1436                                                         timingout = 1;
1437                                                         alarm(RETRYTIME);
1438                                                 }
1439                                                 continue;
1440                                         }
1441                                 }
1442                                 pid = fork();
1443                         }
1444                         if (pid < 0) {
1445                                 bb_perror_msg("fork");
1446                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1447                                         close(ctrl);
1448                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1449                                 sleep(1);
1450                                 continue;
1451                         }
1452                         if (pid && sep->se_wait) {
1453                                 sep->se_wait = pid;
1454                                 FD_CLR(sep->se_fd, &allsock);
1455                                 nsock--;
1456                         }
1457                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1458                         if (pid == 0) {
1459 #ifdef INETD_FEATURE_ENABLED
1460                                 if (sep->se_bi) {
1461                                         (*sep->se_bi->bi_fn)(ctrl, sep);
1462                                 } else
1463 #endif
1464                                 {
1465                                         pwd = getpwnam(sep->se_user);
1466                                         if (pwd == NULL) {
1467                                                 bb_error_msg("getpwnam: %s: no such user", sep->se_user);
1468                                                 goto do_exit1;
1469                                         }
1470                                         if (setsid() < 0)
1471                                                 bb_perror_msg("%s: setsid", sep->se_service);
1472                                         if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1473                                                 bb_error_msg("getgrnam: %s: no such group", sep->se_group);
1474                                                 goto do_exit1;
1475                                         }
1476                                         if (uid != 0) {
1477                                                 /* a user running private inetd */
1478                                                 if (uid != pwd->pw_uid)
1479                                                         _exit(1);
1480                                         } else if (pwd->pw_uid) {
1481                                                 if (sep->se_group)
1482                                                         pwd->pw_gid = grp->gr_gid;
1483                                                 xsetgid((gid_t) pwd->pw_gid);
1484                                                 initgroups(pwd->pw_name, pwd->pw_gid);
1485                                                 xsetuid((uid_t) pwd->pw_uid);
1486                                         } else if (sep->se_group) {
1487                                                 xsetgid(grp->gr_gid);
1488                                                 setgroups(1, &grp->gr_gid);
1489                                         }
1490                                         dup2(ctrl, 0);
1491                                         if (ctrl) close(ctrl);
1492                                         dup2(0, 1);
1493                                         dup2(0, 2);
1494                                         if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1495                                                 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1496                                                         bb_perror_msg("setrlimit");
1497                                         closelog();
1498                                         for (tmpint = rlim_ofile_cur - 1; --tmpint > 2;)
1499                                                 (void) close(tmpint);
1500                                         sigaction(SIGPIPE, &sapipe, NULL);
1501                                         execv(sep->se_server, sep->se_argv);
1502                                         bb_perror_msg("execv %s", sep->se_server);
1503  do_exit1:
1504                                         if (sep->se_socktype != SOCK_STREAM)
1505                                                 recv(0, buf, sizeof(buf), 0);
1506                                         _exit(1);
1507                                 }
1508                         }
1509                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1510                                 close(ctrl);
1511                 } /* for (sep = servtab...) */
1512         } /* for (;;) */
1513 }
1514
1515 /*
1516  * Internet services provided internally by inetd:
1517  */
1518 #define BUFSIZE 4096
1519
1520 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
1521         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN || \
1522         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1523 static int dg_badinput(struct sockaddr_in *dg_sin)
1524 {
1525         if (ntohs(dg_sin->sin_port) < IPPORT_RESERVED)
1526                 return 1;
1527         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST))
1528                 return 1;
1529         /* XXX compare against broadcast addresses in SIOCGIFCONF list? */
1530         return 0;
1531 }
1532 #endif
1533
1534 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1535 /* Echo service -- echo data back */
1536 /* ARGSUSED */
1537 static void
1538 echo_stream(int s, servtab_t *sep)
1539 {
1540         char buffer[BUFSIZE];
1541         int i;
1542
1543         inetd_setproctitle(sep->se_service, s);
1544         while (1) {
1545                 i = read(s, buffer, sizeof(buffer));
1546                 if (i <= 0) break;
1547                 /* FIXME: this isnt correct - safe_write()? */
1548                 if (write(s, buffer, i) <= 0) break;
1549         }
1550         exit(0);
1551 }
1552
1553 /* Echo service -- echo data back */
1554 /* ARGSUSED */
1555 static void
1556 echo_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1557 {
1558         char buffer[BUFSIZE];
1559         int i;
1560         socklen_t size;
1561         /* struct sockaddr_storage ss; */
1562         struct sockaddr sa;
1563
1564         size = sizeof(sa);
1565         i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size);
1566         if (i < 0)
1567                 return;
1568         if (dg_badinput((struct sockaddr_in *) &sa))
1569                 return;
1570         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1571 }
1572 #endif  /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1573
1574 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1575 /* Discard service -- ignore data */
1576 /* ARGSUSED */
1577 static void
1578 discard_stream(int s, servtab_t *sep)
1579 {
1580         char buffer[BUFSIZE];
1581
1582         inetd_setproctitle(sep->se_service, s);
1583         while (1) {
1584                 errno = 0;
1585                 if (read(s, buffer, sizeof(buffer)) <= 0 && errno != EINTR)
1586                         exit(0);
1587         }
1588 }
1589
1590 /* Discard service -- ignore data */
1591 /* ARGSUSED */
1592 static void
1593 discard_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1594 {
1595         char buffer[BUFSIZE];
1596
1597         (void) read(s, buffer, sizeof(buffer));
1598 }
1599 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1600
1601
1602 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1603 #define LINESIZ 72
1604 static char ring[128];
1605 static char *endring;
1606
1607 static void
1608 initring(void)
1609 {
1610         int i;
1611
1612         endring = ring;
1613
1614         for (i = 0; i <= 128; ++i)
1615                 if (isprint(i))
1616                         *endring++ = i;
1617 }
1618
1619 /* Character generator */
1620 /* ARGSUSED */
1621 static void
1622 chargen_stream(int s, servtab_t *sep)
1623 {
1624         char *rs;
1625         int len;
1626         char text[LINESIZ + 2];
1627
1628         inetd_setproctitle(sep->se_service, s);
1629
1630         if (!endring) {
1631                 initring();
1632                 rs = ring;
1633         }
1634
1635         text[LINESIZ] = '\r';
1636         text[LINESIZ + 1] = '\n';
1637         rs = ring;
1638         for (;;) {
1639                 len = endring - rs;
1640                 if (len >= LINESIZ)
1641                         memmove(text, rs, LINESIZ);
1642                 else {
1643                         memmove(text, rs, len);
1644                         memmove(text + len, ring, LINESIZ - len);
1645                 }
1646                 if (++rs == endring)
1647                         rs = ring;
1648                 if (write(s, text, sizeof(text)) != sizeof(text))
1649                         break;
1650         }
1651         exit(0);
1652 }
1653
1654 /* Character generator */
1655 /* ARGSUSED */
1656 static void
1657 chargen_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1658 {
1659         /* struct sockaddr_storage ss; */
1660         struct sockaddr sa;
1661         static char *rs;
1662         int len;
1663         char text[LINESIZ + 2];
1664         socklen_t size;
1665
1666         if (endring == 0) {
1667                 initring();
1668                 rs = ring;
1669         }
1670
1671         size = sizeof(sa);
1672         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1673                 return;
1674         if (dg_badinput((struct sockaddr_in *) &sa))
1675                 return;
1676
1677         if ((len = endring - rs) >= LINESIZ)
1678                 memmove(text, rs, LINESIZ);
1679         else {
1680                 memmove(text, rs, len);
1681                 memmove(text + len, ring, LINESIZ - len);
1682         }
1683         if (++rs == endring)
1684                 rs = ring;
1685         text[LINESIZ] = '\r';
1686         text[LINESIZ + 1] = '\n';
1687         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1688 }
1689 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1690
1691
1692 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1693 /*
1694  * Return a machine readable date and time, in the form of the
1695  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1696  * returns the number of seconds since midnight, Jan 1, 1970,
1697  * we must add 2208988800 seconds to this figure to make up for
1698  * some seventy years Bell Labs was asleep.
1699  */
1700
1701 static unsigned machtime(void)
1702 {
1703         struct timeval tv;
1704
1705         if (gettimeofday(&tv, NULL) < 0) {
1706                 fprintf(stderr, "Unable to get time of day\n");
1707                 return 0L;
1708         }
1709         return htonl((unsigned) tv.tv_sec + 2208988800UL);
1710 }
1711
1712 /* ARGSUSED */
1713 static void
1714 machtime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1715 {
1716         unsigned result;
1717
1718         result = machtime();
1719         (void) write(s, (char *) &result, sizeof(result));
1720 }
1721
1722 /* ARGSUSED */
1723 static void
1724 machtime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1725 {
1726         unsigned result;
1727         /* struct sockaddr_storage ss; */
1728         struct sockaddr sa;
1729         struct sockaddr_in *dg_sin;
1730         socklen_t size;
1731
1732         size = sizeof(sa);
1733         if (recvfrom(s, (char *) &result, sizeof(result), 0, &sa, &size) < 0)
1734                 return;
1735         /* if (dg_badinput((struct sockaddr *)&ss)) */
1736         dg_sin = (struct sockaddr_in *) &sa;
1737         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST) ||
1738                         ntohs(dg_sin->sin_port) < IPPORT_RESERVED / 2)
1739                 return;
1740         result = machtime();
1741         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1742 }
1743 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1744
1745
1746 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1747 /* Return human-readable time of day */
1748 /* ARGSUSED */
1749 static void daytime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1750 {
1751         char buffer[32];
1752         time_t t;
1753
1754         t = time(NULL);
1755
1756 // fdprintf instead?
1757         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1758         (void) write(s, buffer, strlen(buffer));
1759 }
1760
1761 /* Return human-readable time of day */
1762 /* ARGSUSED */
1763 void
1764 daytime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1765 {
1766         char buffer[256];
1767         time_t t;
1768         /* struct sockaddr_storage ss; */
1769         struct sockaddr sa;
1770         socklen_t size;
1771
1772         t = time(NULL);
1773
1774         size = sizeof(sa);
1775         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1776                 return;
1777         if (dg_badinput((struct sockaddr_in *) &sa))
1778                 return;
1779         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1780         (void) sendto(s, buffer, strlen(buffer), 0, &sa, sizeof(sa));
1781 }
1782 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */