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
 194 /* Check unsupporting builtin */
 195 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
 196         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD || \
 197         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME || \
 198         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME || \
 199         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 200 # define INETD_FEATURE_ENABLED
 201 #endif
 202
 203 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
 204         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD || \
 205         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 206 # define INETD_SETPROCTITLE
 207 #endif
 208
 209 typedef int8_t socktype_t;
 210 typedef int8_t family_t;
 211 struct BUG_too_small {
 212         char BUG_socktype_t_too_small[(0
 213                         | SOCK_STREAM
 214                         | SOCK_DGRAM
 215                         | SOCK_RDM
 216                         | SOCK_SEQPACKET
 217                         | SOCK_RAW) <= 127 ? 1 : -1];
 218         char BUG_family_t_too_small[(0
 219                         | AF_INET
 220                         | AF_INET6
 221                         | AF_UNIX) <= 127 ? 1 : -1];
 222 };
 223
 224 typedef struct servtab_t {
 225         /* The most frequently referenced one: */
 226         int se_fd;                            /* open descriptor */
 227         /* NB: 'biggest fields last' saves on code size (~250 bytes) */
 228         char *se_hostaddr;                    /* host address to listen on */
 229         char *se_service;                     /* name of service */
 230         char *se_proto;                       /* protocol used */
 231 #if ENABLE_FEATURE_INETD_RPC
 232         int se_rpcprog;                       /* rpc program number */
 233         int se_rpcversl;                      /* rpc program lowest version */
 234         int se_rpcversh;                      /* rpc program highest version */
 235 #define isrpcservice(sep)       ((sep)->se_rpcversl != 0)
 236 #else
 237 #define isrpcservice(sep)       0
 238 #endif
 239         pid_t se_wait;                        /* single threaded server */
 240         socktype_t se_socktype;               /* type of socket to use */
 241         family_t se_family;                   /* address family */
 242         smallint se_checked;                  /* looked at during merge */
 243         char *se_user;                        /* user name to run as */
 244         char *se_group;                       /* group name to run as */
 245 #ifdef INETD_FEATURE_ENABLED
 246         const struct builtin *se_bi;          /* if built-in, description */
 247 #endif
 248         int se_ctrladdr_size;
 249         int se_max;                           /* max # of instances of this service */
 250         int se_count;                         /* number started since se_time */
 251         struct servtab_t *se_next;
 252         struct timeval se_time;               /* start of se_count */
 253         char *se_server;                      /* server program */
 254 #define MAXARGV 20
 255         char *se_argv[MAXARGV + 1];           /* program arguments */
 256         union {
 257                 struct sockaddr se_un_ctrladdr;
 258                 struct sockaddr_in se_un_ctrladdr_in;
 259 #if ENABLE_FEATURE_IPV6
 260                 struct sockaddr_in6 se_un_ctrladdr_in6;
 261 #endif
 262                 struct sockaddr_un se_un_ctrladdr_un;
 263         } se_un;                              /* bound address */
 264 #define se_ctrladdr     se_un.se_un_ctrladdr
 265 #define se_ctrladdr_in  se_un.se_un_ctrladdr_in
 266 #define se_ctrladdr_in6 se_un.se_un_ctrladdr_in6
 267 #define se_ctrladdr_un  se_un.se_un_ctrladdr_un
 268 } servtab_t;
 269
 270 #ifdef INETD_FEATURE_ENABLED
 271 struct builtin {
 272         const char *bi_service;               /* internally provided service name */
 273         socktype_t bi_socktype;               /* type of socket supported */
 274         uint8_t bi_fork;                      /* 1 if should fork before call */
 275 // Commented since it is always 0
 276 //      uint8_t bi_wait;                      /* 1 if should wait for child */
 277         void (*bi_fn) (int, servtab_t *);
 278 };
 279
 280                 /* Echo received data */
 281 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
 282 static void echo_stream(int, servtab_t *);
 283 static void echo_dg(int, servtab_t *);
 284 #endif
 285                 /* Internet /dev/null */
 286 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
 287 static void discard_stream(int, servtab_t *);
 288 static void discard_dg(int, servtab_t *);
 289 #endif
 290                 /* Return 32 bit time since 1900 */
 291 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
 292 static void machtime_stream(int, servtab_t *);
 293 static void machtime_dg(int, servtab_t *);
 294 #endif
 295                 /* Return human-readable time */
 296 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
 297 static void daytime_stream(int, servtab_t *);
 298 static void daytime_dg(int, servtab_t *);
 299 #endif
 300                 /* Familiar character generator */
 301 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 302 static void chargen_stream(int, servtab_t *);
 303 static void chargen_dg(int, servtab_t *);
 304 #endif
 305
 306 static const struct builtin builtins[] = {
 307 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
 308         /* Echo received data */
 309         {"echo", SOCK_STREAM, 1, echo_stream,},
 310         {"echo", SOCK_DGRAM, 0, echo_dg,},
 311 #endif
 312 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
 313         /* Internet /dev/null */
 314         {"discard", SOCK_STREAM, 1, discard_stream,},
 315         {"discard", SOCK_DGRAM, 0, discard_dg,},
 316 #endif
 317 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
 318         /* Return 32 bit time since 1900 */
 319         {"time", SOCK_STREAM, 0, machtime_stream,},
 320         {"time", SOCK_DGRAM, 0, machtime_dg,},
 321 #endif
 322 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
 323         /* Return human-readable time */
 324         {"daytime", SOCK_STREAM, 0, daytime_stream,},
 325         {"daytime", SOCK_DGRAM, 0, daytime_dg,},
 326 #endif
 327 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 328         /* Familiar character generator */
 329         {"chargen", SOCK_STREAM, 1, chargen_stream,},
 330         {"chargen", SOCK_DGRAM, 0, chargen_dg,},
 331 #endif
 332         { /* zero filled */ }
 333 };
 334 #endif /* INETD_FEATURE_ENABLED */
 335
 336 struct globals {
 337         rlim_t rlim_ofile_cur;
 338         struct rlimit rlim_ofile;
 339         servtab_t *servtab;
 340         int global_queuelen;
 341         int nsock;
 342         int maxsock;
 343         int toomany;
 344         int timingout;
 345         struct servent *sp;
 346         uid_t uid;
 347         const char *config_filename;
 348         FILE *fconfig;
 349         char *defhost;
 350 #ifdef INETD_SETPROCTITLE
 351         char **Argv;
 352         char *LastArg;
 353 #endif
 354 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 355         char *endring;
 356         char *ringpos;
 357         char ring[128];
 358 #endif
 359         fd_set allsock;
 360         /* Used only in nextline() */
 361         char line[80];          /* at least 80, see LINE_SIZE */
 362 };
 363 #define G (*(struct globals*)&bb_common_bufsiz1)
 364 enum { LINE_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line) };
 365 struct BUG_G_too_big {
 366         char BUG_G_too_big[sizeof(G) <= COMMON_BUFSIZE ? 1 : -1];
 367 };
 368 #define rlim_ofile_cur  (G.rlim_ofile_cur )
 369 #define rlim_ofile      (G.rlim_ofile     )
 370 #define servtab         (G.servtab        )
 371 #define global_queuelen (G.global_queuelen)
 372 #define nsock           (G.nsock          )
 373 #define maxsock         (G.maxsock        )
 374 #define toomany         (G.toomany        )
 375 #define timingout       (G.timingout      )
 376 #define sp              (G.sp             )
 377 #define uid             (G.uid            )
 378 #define config_filename (G.config_filename)
 379 #define fconfig         (G.fconfig        )
 380 #define defhost         (G.defhost        )
 381 #define Argv            (G.Argv           )
 382 #define LastArg         (G.LastArg        )
 383 #define endring         (G.endring        )
 384 #define ringpos         (G.ringpos        )
 385 #define ring            (G.ring           )
 386 #define allsock         (G.allsock        )
 387 #define line            (G.line           )
 388 #define INIT_G() do { \
 389         rlim_ofile_cur = OPEN_MAX; \
 390         global_queuelen = 128; \
 391         config_filename = "/etc/inetd.conf"; \
 392 } while (0)
 393
 394 /* xstrdup(NULL) returns NULL, but this one
 395  * will return newly-allocated "" if called with NULL arg
 396  * TODO: audit whether this makes any real difference
 397  */
 398 static char *xxstrdup(char *cp)
 399 {
 400         return xstrdup(cp ? cp : "");
 401 }
 402
 403 static int setconfig(void)
 404 {
 405         free(defhost);
 406         defhost = xstrdup("*");
 407         if (fconfig != NULL) {
 408                 fseek(fconfig, 0L, SEEK_SET);
 409                 return 1;
 410         }
 411         fconfig = fopen(config_filename, "r");
 412         return (fconfig != NULL);
 413 }
 414
 415 static void endconfig(void)
 416 {
 417         if (fconfig) {
 418                 (void) fclose(fconfig);
 419                 fconfig = NULL;
 420         }
 421         free(defhost);
 422         defhost = 0;
 423 }
 424
 425 #if ENABLE_FEATURE_INETD_RPC
 426 static void register_rpc(servtab_t *sep)
 427 {
 428         int n;
 429         struct sockaddr_in ir_sin;
 430         struct protoent *pp;
 431         socklen_t size;
 432
 433         if ((pp = getprotobyname(sep->se_proto + 4)) == NULL) {
 434                 bb_perror_msg("%s: getproto", sep->se_proto);
 435                 return;
 436         }
 437         size = sizeof ir_sin;
 438         if (getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, &size) < 0) {
 439                 bb_perror_msg("%s/%s: getsockname",
 440                                 sep->se_service, sep->se_proto);
 441                 return;
 442         }
 443
 444         for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
 445                 (void) pmap_unset(sep->se_rpcprog, n);
 446                 if (!pmap_set(sep->se_rpcprog, n, pp->p_proto, ntohs(ir_sin.sin_port)))
 447                         bb_perror_msg("%s %s: pmap_set: %u %u %u %u",
 448                                         sep->se_service, sep->se_proto,
 449                                         sep->se_rpcprog, n, pp->p_proto, ntohs(ir_sin.sin_port));
 450         }
 451 }
 452
 453 static void unregister_rpc(servtab_t *sep)
 454 {
 455         int n;
 456
 457         for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
 458                 if (!pmap_unset(sep->se_rpcprog, n))
 459                         bb_error_msg("pmap_unset(%u, %u)", sep->se_rpcprog, n);
 460         }
 461 }
 462 #endif /* FEATURE_INETD_RPC */
 463
 464 static void freeconfig(servtab_t *cp)
 465 {
 466         int i;
 467
 468         free(cp->se_hostaddr);
 469         free(cp->se_service);
 470         free(cp->se_proto);
 471         free(cp->se_user);
 472         free(cp->se_group);
 473         free(cp->se_server);
 474         for (i = 0; i < MAXARGV; i++)
 475                 free(cp->se_argv[i]);
 476 }
 477
 478 static int bump_nofile(void)
 479 {
 480 #define FD_CHUNK        32
 481
 482         struct rlimit rl;
 483
 484         if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
 485                 bb_perror_msg("getrlimit");
 486                 return -1;
 487         }
 488         rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
 489         rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
 490         if (rl.rlim_cur <= rlim_ofile_cur) {
 491                 bb_error_msg("bump_nofile: cannot extend file limit, max = %d",
 492                                                 (int) rl.rlim_cur);
 493                 return -1;
 494         }
 495
 496         if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
 497                 bb_perror_msg("setrlimit");
 498                 return -1;
 499         }
 500
 501         rlim_ofile_cur = rl.rlim_cur;
 502         return 0;
 503 }
 504
 505 static void setup(servtab_t *sep)
 506 {
 507         int r;
 508
 509         sep->se_fd = socket(sep->se_family, sep->se_socktype, 0);
 510         if (sep->se_fd < 0) {
 511                 bb_perror_msg("%s/%s: socket", sep->se_service, sep->se_proto);
 512                 return;
 513         }
 514         setsockopt_reuseaddr(sep->se_fd);
 515
 516 #if ENABLE_FEATURE_INETD_RPC
 517         if (isrpcservice(sep)) {
 518                 struct passwd *pwd;
 519
 520                 /*
 521                  * for RPC services, attempt to use a reserved port
 522                  * if they are going to be running as root.
 523                  *
 524                  * Also, zero out the port for all RPC services; let bind()
 525                  * find one.
 526                  */
 527                 sep->se_ctrladdr_in.sin_port = 0;
 528                 if (sep->se_user && (pwd = getpwnam(sep->se_user)) &&
 529                                 pwd->pw_uid == 0 && uid == 0)
 530                         r = bindresvport(sep->se_fd, &sep->se_ctrladdr_in);
 531                 else {
 532                         r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 533                         if (r == 0) {
 534                                 socklen_t len = sep->se_ctrladdr_size;
 535                                 int saveerrno = errno;
 536
 537                                 /* update se_ctrladdr_in.sin_port */
 538                                 r = getsockname(sep->se_fd, &sep->se_ctrladdr, &len);
 539                                 if (r <= 0)
 540                                         errno = saveerrno;
 541                         }
 542                 }
 543         } else
 544 #endif
 545                 r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 546         if (r < 0) {
 547                 bb_perror_msg("%s/%s (%d): bind",
 548                                 sep->se_service, sep->se_proto, sep->se_ctrladdr.sa_family);
 549                 close(sep->se_fd);
 550                 sep->se_fd = -1;
 551                 if (!timingout) {
 552                         timingout = 1;
 553                         alarm(RETRYTIME);
 554                 }
 555                 return;
 556         }
 557         if (sep->se_socktype == SOCK_STREAM)
 558                 listen(sep->se_fd, global_queuelen);
 559
 560         FD_SET(sep->se_fd, &allsock);
 561         nsock++;
 562         if (sep->se_fd > maxsock) {
 563                 maxsock = sep->se_fd;
 564                 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
 565                         bump_nofile();
 566         }
 567 }
 568
 569 static char *nextline(void)
 570 {
 571         char *cp;
 572         FILE *fd = fconfig;
 573
 574         if (fgets(line, LINE_SIZE, fd) == NULL)
 575                 return NULL;
 576         cp = strchr(line, '\n');
 577         if (cp)
 578                 *cp = '\0';
 579         return line;
 580 }
 581
 582 static char *skip(char **cpp) /* int report; */
 583 {
 584         char *cp = *cpp;
 585         char *start;
 586
 587 /* erp: */
 588         if (*cpp == NULL) {
 589                 /* if (report) */
 590                 /* bb_error_msg("syntax error in inetd config file"); */
 591                 return NULL;
 592         }
 593
 594  again:
 595         while (*cp == ' ' || *cp == '\t')
 596                 cp++;
 597         if (*cp == '\0') {
 598                 int c;
 599
 600                 c = getc(fconfig);
 601                 ungetc(c, fconfig);
 602                 if (c == ' ' || c == '\t') {
 603                         cp = nextline();
 604                         if (cp)
 605                                 goto again;
 606                 }
 607                 *cpp = NULL;
 608                 /* goto erp; */
 609                 return NULL;
 610         }
 611         start = cp;
 612         while (*cp && *cp != ' ' && *cp != '\t')
 613                 cp++;
 614         if (*cp != '\0')
 615                 *cp++ = '\0';
 616         /* if ((*cpp = cp) == NULL) */
 617         /* goto erp; */
 618
 619         *cpp = cp;
 620         return start;
 621 }
 622
 623 static servtab_t *new_servtab(void)
 624 {
 625         return xmalloc(sizeof(servtab_t));
 626 }
 627
 628 static servtab_t *dupconfig(servtab_t *sep)
 629 {
 630         servtab_t *newtab;
 631         int argc;
 632
 633         newtab = new_servtab();
 634         memset(newtab, 0, sizeof(servtab_t));
 635         newtab->se_service = xstrdup(sep->se_service);
 636         newtab->se_socktype = sep->se_socktype;
 637         newtab->se_family = sep->se_family;
 638         newtab->se_proto = xstrdup(sep->se_proto);
 639 #if ENABLE_FEATURE_INETD_RPC
 640         newtab->se_rpcprog = sep->se_rpcprog;
 641         newtab->se_rpcversl = sep->se_rpcversl;
 642         newtab->se_rpcversh = sep->se_rpcversh;
 643 #endif
 644         newtab->se_wait = sep->se_wait;
 645         newtab->se_user = xstrdup(sep->se_user);
 646         newtab->se_group = xstrdup(sep->se_group);
 647 #ifdef INETD_FEATURE_ENABLED
 648         newtab->se_bi = sep->se_bi;
 649 #endif
 650         newtab->se_server = xstrdup(sep->se_server);
 651
 652         for (argc = 0; argc <= MAXARGV; argc++)
 653                 newtab->se_argv[argc] = xstrdup(sep->se_argv[argc]);
 654         newtab->se_max = sep->se_max;
 655
 656         return newtab;
 657 }
 658
 659 static servtab_t *getconfigent(void)
 660 {
 661         servtab_t *sep;
 662         int argc;
 663         char *cp, *arg;
 664         char *hostdelim;
 665         servtab_t *nsep;
 666         servtab_t *psep;
 667
 668         sep = new_servtab();
 669
 670         /* memset(sep, 0, sizeof *sep); */
 671  more:
 672         /* freeconfig(sep); */
 673
 674         while ((cp = nextline()) && *cp == '#') /* skip comment line */;
 675         if (cp == NULL) {
 676                 /* free(sep); */
 677                 return NULL;
 678         }
 679
 680         memset((char *) sep, 0, sizeof *sep);
 681         arg = skip(&cp);
 682         if (arg == NULL) {
 683                 /* A blank line. */
 684                 goto more;
 685         }
 686
 687         /* Check for a host name. */
 688         hostdelim = strrchr(arg, ':');
 689         if (hostdelim) {
 690                 *hostdelim = '\0';
 691                 sep->se_hostaddr = xstrdup(arg);
 692                 arg = hostdelim + 1;
 693                 /*
 694                  * If the line is of the form `host:', then just change the
 695                  * default host for the following lines.
 696                  */
 697                 if (*arg == '\0') {
 698                         arg = skip(&cp);
 699                         if (cp == NULL) {
 700                                 free(defhost);
 701                                 defhost = sep->se_hostaddr;
 702                                 goto more;
 703                         }
 704                 }
 705         } else
 706                 sep->se_hostaddr = xxstrdup(defhost);
 707
 708         sep->se_service = xxstrdup(arg);
 709         arg = skip(&cp);
 710
 711         {
 712                 static int8_t SOCK_xxx[] ALIGN1 = {
 713                         -1,
 714                         SOCK_STREAM, SOCK_DGRAM, SOCK_RDM,
 715                         SOCK_SEQPACKET, SOCK_RAW
 716                 };
 717                 sep->se_socktype = SOCK_xxx[1 + index_in_strings(
 718                         "stream""\0" "dgram""\0" "rdm""\0"
 719                         "seqpacket""\0" "raw""\0"
 720                         , arg)];
 721         }
 722
 723         sep->se_proto = xxstrdup(skip(&cp));
 724
 725         if (strcmp(sep->se_proto, "unix") == 0) {
 726                 sep->se_family = AF_UNIX;
 727         } else {
 728                 sep->se_family = AF_INET;
 729                 if (sep->se_proto[strlen(sep->se_proto) - 1] == '6')
 730 #if ENABLE_FEATURE_IPV6
 731                         sep->se_family = AF_INET6;
 732 #else
 733                         bb_error_msg("%s: IPV6 not supported", sep->se_proto);
 734 #endif
 735                 if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
 736 #if ENABLE_FEATURE_INETD_RPC
 737                         char *p, *ccp;
 738                         long l;
 739
 740                         p = strchr(sep->se_service, '/');
 741                         if (p == 0) {
 742                                 bb_error_msg("%s: no rpc version", sep->se_service);
 743                                 goto more;
 744                         }
 745                         *p++ = '\0';
 746                         l = strtol(p, &ccp, 0);
 747                         if (ccp == p || l < 0 || l > INT_MAX) {
 748  badafterall:
 749                                 bb_error_msg("%s/%s: bad rpc version", sep->se_service, p);
 750                                 goto more;
 751                         }
 752                         sep->se_rpcversl = sep->se_rpcversh = l;
 753                         if (*ccp == '-') {
 754                                 p = ccp + 1;
 755                                 l = strtol(p, &ccp, 0);
 756                                 if (ccp == p || l < 0 || l > INT_MAX || l < sep->se_rpcversl || *ccp)
 757                                         goto badafterall;
 758                                 sep->se_rpcversh = l;
 759                         } else if (*ccp != '\0')
 760                                 goto badafterall;
 761 #else
 762                         bb_error_msg("%s: rpc services not supported", sep->se_service);
 763 #endif
 764                 }
 765         }
 766         arg = skip(&cp);
 767         if (arg == NULL)
 768                 goto more;
 769
 770         {
 771                 char *s = strchr(arg, '.');
 772                 if (s) {
 773                         *s++ = '\0';
 774                         sep->se_max = xatoi(s);
 775                 } else
 776                         sep->se_max = toomany;
 777         }
 778         sep->se_wait = strcmp(arg, "wait") == 0;
 779         /* if ((arg = skip(&cp, 1)) == NULL) */
 780         /* goto more; */
 781         sep->se_user = xxstrdup(skip(&cp));
 782         arg = strchr(sep->se_user, '.');
 783         if (arg == NULL)
 784                 arg = strchr(sep->se_user, ':');
 785         if (arg) {
 786                 *arg++ = '\0';
 787                 sep->se_group = xstrdup(arg);
 788         }
 789
 790         arg = skip(&cp);
 791         sep->se_server = xxstrdup(arg);
 792         if (strcmp(sep->se_server, "internal") == 0) {
 793 #ifdef INETD_FEATURE_ENABLED
 794                 const struct builtin *bi;
 795
 796                 for (bi = builtins; bi->bi_service; bi++)
 797                         if (bi->bi_socktype == sep->se_socktype
 798                          && strcmp(bi->bi_service, sep->se_service) == 0)
 799                                 break;
 800                 if (bi->bi_service == 0) {
 801                         bb_error_msg("internal service %s unknown", sep->se_service);
 802                         goto more;
 803                 }
 804                 sep->se_bi = bi;
 805                 sep->se_wait = 0; /* = bi->bi_wait; - always 0 */
 806 #else
 807                 bb_perror_msg("internal service %s unknown", sep->se_service);
 808                 goto more;
 809 #endif
 810         }
 811 #ifdef INETD_FEATURE_ENABLED
 812                 else
 813                 sep->se_bi = NULL;
 814 #endif
 815         argc = 0;
 816         for (; cp; arg = skip(&cp)) {
 817                 if (argc < MAXARGV)
 818                         sep->se_argv[argc++] = xxstrdup(arg);
 819         }
 820         while (argc <= MAXARGV)
 821                 sep->se_argv[argc++] = NULL;
 822
 823         /*
 824          * Now that we've processed the entire line, check if the hostname
 825          * specifier was a comma separated list of hostnames. If so
 826          * we'll make new entries for each address.
 827          */
 828         while ((hostdelim = strrchr(sep->se_hostaddr, ',')) != NULL) {
 829                 nsep = dupconfig(sep);
 830
 831                 /*
 832                  * NULL terminate the hostname field of the existing entry,
 833                  * and make a dup for the new entry.
 834                  */
 835                 *hostdelim++ = '\0';
 836                 nsep->se_hostaddr = xstrdup(hostdelim);
 837
 838                 nsep->se_next = sep->se_next;
 839                 sep->se_next = nsep;
 840         }
 841
 842         nsep = sep;
 843         while (nsep != NULL) {
 844                 nsep->se_checked = 1;
 845                 if (nsep->se_family == AF_INET) {
 846                         if (LONE_CHAR(nsep->se_hostaddr, '*'))
 847                                 nsep->se_ctrladdr_in.sin_addr.s_addr = INADDR_ANY;
 848                         else if (!inet_aton(nsep->se_hostaddr, &nsep->se_ctrladdr_in.sin_addr)) {
 849                                 int i;
 850                                 struct hostent *hp;
 851
 852                                 hp = gethostbyname(nsep->se_hostaddr);
 853                                 if (hp == NULL) {
 854                                         bb_error_msg("%s: unknown host", nsep->se_hostaddr);
 855                                         nsep->se_checked = 0;
 856                                         goto skip;
 857                                 }
 858                                 if (hp->h_addrtype != AF_INET) {
 859                                         bb_error_msg("%s: address isn't an Internet "
 860                                                                   "address", nsep->se_hostaddr);
 861                                         nsep->se_checked = 0;
 862                                         goto skip;
 863                                 }
 864                                 i = 1;
 865                                 memmove(&nsep->se_ctrladdr_in.sin_addr,
 866                                                            hp->h_addr_list[0], sizeof(struct in_addr));
 867                                 while (hp->h_addr_list[i] != NULL) {
 868                                         psep = dupconfig(nsep);
 869                                         psep->se_hostaddr = xxstrdup(nsep->se_hostaddr);
 870                                         psep->se_checked = 1;
 871                                         memmove(&psep->se_ctrladdr_in.sin_addr,
 872                                                              hp->h_addr_list[i], sizeof(struct in_addr));
 873                                         psep->se_ctrladdr_size = sizeof(psep->se_ctrladdr_in);
 874                                         i++;
 875                                         /* Prepend to list, don't want to look up */
 876                                         /* its hostname again. */
 877                                         psep->se_next = sep;
 878                                         sep = psep;
 879                                 }
 880                         }
 881                 }
 882 /* XXX BUG?: is this skip: label supposed to remain? */
 883  skip:
 884                 nsep = nsep->se_next;
 885         }
 886
 887         /*
 888          * Finally, free any entries which failed the gethostbyname
 889          * check.
 890          */
 891         psep = NULL;
 892         nsep = sep;
 893         while (nsep != NULL) {
 894                 servtab_t *tsep;
 895
 896                 if (nsep->se_checked == 0) {
 897                         tsep = nsep;
 898                         if (psep == NULL) {
 899                                 sep = nsep->se_next;
 900                                 nsep = sep;
 901                         } else {
 902                                 nsep = nsep->se_next;
 903                                 psep->se_next = nsep;
 904                         }
 905                         freeconfig(tsep);
 906                 } else {
 907                         nsep->se_checked = 0;
 908                         psep = nsep;
 909                         nsep = nsep->se_next;
 910                 }
 911         }
 912
 913         return sep;
 914 }
 915
 916 #define Block_Using_Signals(m) do { \
 917         sigemptyset(&m); \
 918         sigaddset(&m, SIGCHLD); \
 919         sigaddset(&m, SIGHUP); \
 920         sigaddset(&m, SIGALRM); \
 921         sigprocmask(SIG_BLOCK, &m, NULL); \
 922 } while (0)
 923
 924 static servtab_t *enter(servtab_t *cp)
 925 {
 926         servtab_t *sep;
 927         sigset_t omask;
 928
 929         sep = new_servtab();
 930         *sep = *cp;
 931         sep->se_fd = -1;
 932 #if ENABLE_FEATURE_INETD_RPC
 933         sep->se_rpcprog = -1;
 934 #endif
 935         Block_Using_Signals(omask);
 936         sep->se_next = servtab;
 937         servtab = sep;
 938         sigprocmask(SIG_UNBLOCK, &omask, NULL);
 939         return sep;
 940 }
 941
 942 static int matchconf(servtab_t *old, servtab_t *new)
 943 {
 944         if (strcmp(old->se_service, new->se_service) != 0)
 945                 return 0;
 946
 947         if (strcmp(old->se_hostaddr, new->se_hostaddr) != 0)
 948                 return 0;
 949
 950         if (strcmp(old->se_proto, new->se_proto) != 0)
 951                 return 0;
 952
 953         /*
 954          * If the new servtab is bound to a specific address, check that the
 955          * old servtab is bound to the same entry. If the new service is not
 956          * bound to a specific address then the check of se_hostaddr above
 957          * is sufficient.
 958          */
 959
 960         if (old->se_family == AF_INET && new->se_family == AF_INET &&
 961                         memcmp(&old->se_ctrladdr_in.sin_addr,
 962                                         &new->se_ctrladdr_in.sin_addr,
 963                                         sizeof(new->se_ctrladdr_in.sin_addr)) != 0)
 964                 return 0;
 965
 966 #if ENABLE_FEATURE_IPV6
 967         if (old->se_family == AF_INET6 && new->se_family == AF_INET6 &&
 968                         memcmp(&old->se_ctrladdr_in6.sin6_addr,
 969                                         &new->se_ctrladdr_in6.sin6_addr,
 970                                         sizeof(new->se_ctrladdr_in6.sin6_addr)) != 0)
 971                 return 0;
 972 #endif
 973         return 1;
 974 }
 975
 976 static void config(int sig ATTRIBUTE_UNUSED)
 977 {
 978         servtab_t *sep, *cp, **sepp;
 979         sigset_t omask;
 980         size_t n;
 981         char protoname[10];
 982
 983         if (!setconfig()) {
 984                 bb_simple_perror_msg(config_filename);
 985                 return;
 986         }
 987         for (sep = servtab; sep; sep = sep->se_next)
 988                 sep->se_checked = 0;
 989         cp = getconfigent();
 990         while (cp != NULL) {
 991                 for (sep = servtab; sep; sep = sep->se_next)
 992                         if (matchconf(sep, cp))
 993                                 break;
 994
 995                 if (sep != 0) {
 996                         int i;
 997
 998 #define SWAP(type, a, b) do {type c=(type)a; a=(type)b; b=(type)c;} while (0)
 999
1000                         Block_Using_Signals(omask);
1001                         /*
1002                          * sep->se_wait may be holding the pid of a daemon
1003                          * that we're waiting for.  If so, don't overwrite
1004                          * it unless the config file explicitly says don't
1005                          * wait.
1006                          */
1007                         if (
1008 #ifdef INETD_FEATURE_ENABLED
1009                                 cp->se_bi == 0 &&
1010 #endif
1011                                 (sep->se_wait == 1 || cp->se_wait == 0))
1012                                 sep->se_wait = cp->se_wait;
1013                         SWAP(int, cp->se_max, sep->se_max);
1014                         SWAP(char *, sep->se_user, cp->se_user);
1015                         SWAP(char *, sep->se_group, cp->se_group);
1016                         SWAP(char *, sep->se_server, cp->se_server);
1017                         for (i = 0; i < MAXARGV; i++)
1018                                 SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
1019 #undef SWAP
1020
1021 #if ENABLE_FEATURE_INETD_RPC
1022                         if (isrpcservice(sep))
1023                                 unregister_rpc(sep);
1024                         sep->se_rpcversl = cp->se_rpcversl;
1025                         sep->se_rpcversh = cp->se_rpcversh;
1026 #endif
1027                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1028                         freeconfig(cp);
1029                 } else {
1030                         sep = enter(cp);
1031                 }
1032                 sep->se_checked = 1;
1033
1034                 switch (sep->se_family) {
1035                 case AF_UNIX:
1036                         if (sep->se_fd != -1)
1037                                 break;
1038                         (void) unlink(sep->se_service);
1039                         n = strlen(sep->se_service);
1040                         if (n > sizeof sep->se_ctrladdr_un.sun_path - 1)
1041                                 n = sizeof sep->se_ctrladdr_un.sun_path - 1;
1042                         safe_strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n + 1);
1043                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
1044                         sep->se_ctrladdr_size = n + sizeof sep->se_ctrladdr_un.sun_family;
1045                         setup(sep);
1046                         break;
1047                 case AF_INET:
1048                         sep->se_ctrladdr_in.sin_family = AF_INET;
1049                         /* se_ctrladdr_in was set in getconfigent */
1050                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
1051
1052 #if ENABLE_FEATURE_INETD_RPC
1053                         if (isrpcservice(sep)) {
1054                                 struct rpcent *rp;
1055                                 // FIXME: atoi_or_else(str, 0) would be handy here
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                                 // FIXME: atoi_or_else(str, 0) would be handy here
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_in.sin_port) {
1087                                         sep->se_ctrladdr_in.sin_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 #if ENABLE_FEATURE_IPV6
1100                 case AF_INET6:
1101                         sep->se_ctrladdr_in6.sin6_family = AF_INET6;
1102                         /* se_ctrladdr_in was set in getconfigent */
1103                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in6;
1104
1105 #if ENABLE_FEATURE_INETD_RPC
1106                         if (isrpcservice(sep)) {
1107                                 struct rpcent *rp;
1108
1109                                 sep->se_rpcprog = atoi(sep->se_service);
1110                                 if (sep->se_rpcprog == 0) {
1111                                         rp = getrpcbyname(sep->se_service);
1112                                         if (rp == 0) {
1113                                                 bb_error_msg("%s: unknown rpc service", sep->se_service);
1114                                                 goto serv_unknown;
1115                                         }
1116                                         sep->se_rpcprog = rp->r_number;
1117                                 }
1118                                 if (sep->se_fd == -1)
1119                                         setup(sep);
1120                                 if (sep->se_fd != -1)
1121                                         register_rpc(sep);
1122                         } else
1123 #endif
1124                         {
1125                                 uint16_t port = htons(atoi(sep->se_service));
1126
1127                                 if (!port) {
1128                                          /*XXX*/ strncpy(protoname, sep->se_proto, sizeof(protoname));
1129                                         if (isdigit(protoname[strlen(protoname) - 1]))
1130                                                 protoname[strlen(protoname) - 1] = '\0';
1131                                         sp = getservbyname(sep->se_service, protoname);
1132                                         if (sp == 0) {
1133                                                 bb_error_msg("%s/%s: unknown service",
1134                                                                 sep->se_service, sep->se_proto);
1135                                                 goto serv_unknown;
1136                                         }
1137                                         port = sp->s_port;
1138                                 }
1139                                 if (port != sep->se_ctrladdr_in6.sin6_port) {
1140                                         sep->se_ctrladdr_in6.sin6_port = port;
1141                                         if (sep->se_fd != -1) {
1142                                                 FD_CLR(sep->se_fd, &allsock);
1143                                                 nsock--;
1144                                                 (void) close(sep->se_fd);
1145                                         }
1146                                         sep->se_fd = -1;
1147                                 }
1148                                 if (sep->se_fd == -1)
1149                                         setup(sep);
1150                         }
1151                         break;
1152 #endif /* FEATURE_IPV6 */
1153                 }
1154  serv_unknown:
1155                 if (cp->se_next != NULL) {
1156                         servtab_t *tmp = cp;
1157
1158                         cp = cp->se_next;
1159                         free(tmp);
1160                 } else {
1161                         free(cp);
1162                         cp = getconfigent();
1163                 }
1164         }
1165         endconfig();
1166         /*
1167          * Purge anything not looked at above.
1168          */
1169         Block_Using_Signals(omask);
1170         sepp = &servtab;
1171         while ((sep = *sepp)) {
1172                 if (sep->se_checked) {
1173                         sepp = &sep->se_next;
1174                         continue;
1175                 }
1176                 *sepp = sep->se_next;
1177                 if (sep->se_fd != -1) {
1178                         FD_CLR(sep->se_fd, &allsock);
1179                         nsock--;
1180                         (void) close(sep->se_fd);
1181                 }
1182 #if ENABLE_FEATURE_INETD_RPC
1183                 if (isrpcservice(sep))
1184                         unregister_rpc(sep);
1185 #endif
1186                 if (sep->se_family == AF_UNIX)
1187                         (void) unlink(sep->se_service);
1188                 freeconfig(sep);
1189                 free(sep);
1190         }
1191         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1192 }
1193
1194
1195 static void reapchild(int sig ATTRIBUTE_UNUSED)
1196 {
1197         pid_t pid;
1198         int save_errno = errno, status;
1199         servtab_t *sep;
1200
1201         for (;;) {
1202                 pid = wait3(&status, WNOHANG, NULL);
1203                 if (pid <= 0)
1204                         break;
1205                 for (sep = servtab; sep; sep = sep->se_next)
1206                         if (sep->se_wait == pid) {
1207                                 if (WIFEXITED(status) && WEXITSTATUS(status))
1208                                         bb_error_msg("%s: exit status 0x%x",
1209                                                         sep->se_server, WEXITSTATUS(status));
1210                                 else if (WIFSIGNALED(status))
1211                                         bb_error_msg("%s: exit signal 0x%x",
1212                                                         sep->se_server, WTERMSIG(status));
1213                                 sep->se_wait = 1;
1214                                 FD_SET(sep->se_fd, &allsock);
1215                                 nsock++;
1216                         }
1217         }
1218         errno = save_errno;
1219 }
1220
1221 static void retry(int sig ATTRIBUTE_UNUSED)
1222 {
1223         servtab_t *sep;
1224
1225         timingout = 0;
1226         for (sep = servtab; sep; sep = sep->se_next) {
1227                 if (sep->se_fd == -1) {
1228                         switch (sep->se_family) {
1229                         case AF_UNIX:
1230                         case AF_INET:
1231 #if ENABLE_FEATURE_IPV6
1232                         case AF_INET6:
1233 #endif
1234                                 setup(sep);
1235 #if ENABLE_FEATURE_INETD_RPC
1236                                 if (sep->se_fd != -1 && isrpcservice(sep))
1237                                         register_rpc(sep);
1238 #endif
1239                                 break;
1240                         }
1241                 }
1242         }
1243 }
1244
1245 static void goaway(int sig ATTRIBUTE_UNUSED)
1246 {
1247         servtab_t *sep;
1248
1249         /* XXX signal race walking sep list */
1250         for (sep = servtab; sep; sep = sep->se_next) {
1251                 if (sep->se_fd == -1)
1252                         continue;
1253
1254                 switch (sep->se_family) {
1255                 case AF_UNIX:
1256                         (void) unlink(sep->se_service);
1257                         break;
1258                 case AF_INET:
1259 #if ENABLE_FEATURE_IPV6
1260                 case AF_INET6:
1261 #endif
1262 #if ENABLE_FEATURE_INETD_RPC
1263                         if (sep->se_wait == 1 && isrpcservice(sep))
1264                                 unregister_rpc(sep);   /* XXX signal race */
1265 #endif
1266                         break;
1267                 }
1268                 (void) close(sep->se_fd);
1269         }
1270         remove_pidfile(_PATH_INETDPID);
1271         exit(0);
1272 }
1273
1274
1275 #ifdef INETD_SETPROCTITLE
1276
1277 static void
1278 inetd_setproctitle(char *a, int s)
1279 {
1280         socklen_t size;
1281         char *cp;
1282         struct sockaddr_in prt_sin;
1283         char buf[80];
1284
1285         cp = Argv[0];
1286         size = sizeof(prt_sin);
1287         (void) snprintf(buf, sizeof buf, "-%s", a);
1288         if (getpeername(s, (struct sockaddr *) &prt_sin, &size) == 0) {
1289                 char *sa = inet_ntoa(prt_sin.sin_addr);
1290
1291                 buf[sizeof(buf) - 1 - strlen(sa) - 3] = '\0';
1292                 strcat(buf, " [");
1293                 strcat(buf, sa);
1294                 strcat(buf, "]");
1295         }
1296         strncpy(cp, buf, LastArg - cp);
1297         cp += strlen(cp);
1298         while (cp < LastArg)
1299                 *cp++ = ' ';
1300 }
1301 #endif
1302
1303
1304 int inetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1305 int inetd_main(int argc, char **argv)
1306 {
1307         servtab_t *sep;
1308         struct passwd *pwd;
1309         struct group *grp = NULL;
1310         int tmpint;
1311         struct sigaction sa, sapipe;
1312         int opt;
1313         pid_t pid;
1314         char buf[50];
1315         char *stoomany;
1316         sigset_t omask, wait_mask;
1317 #ifdef INETD_SETPROCTITLE
1318         char **envp;
1319 #endif
1320
1321         INIT_G();
1322
1323 #ifdef INETD_SETPROCTITLE
1324         envp = environ;
1325         Argv = argv;
1326         if (envp == 0 || *envp == 0)
1327                 envp = argv;
1328         while (*envp)
1329                 envp++;
1330         LastArg = envp[-1] + strlen(envp[-1]);
1331 #endif
1332
1333         uid = getuid();
1334         if (uid != 0)
1335                 config_filename = NULL;
1336
1337         opt = getopt32(argv, "R:f", &stoomany);
1338         if (opt & 1)
1339                 toomany = xatoi_u(stoomany);
1340         argv += optind;
1341         argc -= optind;
1342         if (argc)
1343                 config_filename = argv[0];
1344         if (config_filename == NULL)
1345                 bb_error_msg_and_die("non-root must specify a config file");
1346
1347         if (!(opt & 2))
1348                 bb_daemonize_or_rexec(0, argv - optind);
1349         else
1350                 bb_sanitize_stdio();
1351         openlog(applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
1352         logmode = LOGMODE_SYSLOG;
1353
1354         if (uid == 0) {
1355                 /* If run by hand, ensure groups vector gets trashed */
1356                 gid_t gid = getgid();
1357                 setgroups(1, &gid);
1358         }
1359
1360         write_pidfile(_PATH_INETDPID);
1361
1362         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
1363                 bb_perror_msg("getrlimit");
1364         } else {
1365                 rlim_ofile_cur = rlim_ofile.rlim_cur;
1366                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
1367                         rlim_ofile_cur = OPEN_MAX;
1368         }
1369
1370         memset((char *) &sa, 0, sizeof(sa));
1371         sigemptyset(&sa.sa_mask);
1372         sigaddset(&sa.sa_mask, SIGALRM);
1373         sigaddset(&sa.sa_mask, SIGCHLD);
1374         sigaddset(&sa.sa_mask, SIGHUP);
1375         sa.sa_handler = retry;
1376         sigaction(SIGALRM, &sa, NULL);
1377         config(SIGHUP);
1378         sa.sa_handler = config;
1379         sigaction(SIGHUP, &sa, NULL);
1380         sa.sa_handler = reapchild;
1381         sigaction(SIGCHLD, &sa, NULL);
1382         sa.sa_handler = goaway;
1383         sigaction(SIGTERM, &sa, NULL);
1384         sa.sa_handler = goaway;
1385         sigaction(SIGINT, &sa, NULL);
1386         sa.sa_handler = SIG_IGN;
1387         sigaction(SIGPIPE, &sa, &sapipe);
1388         memset(&wait_mask, 0, sizeof(wait_mask));
1389         {
1390                 /* space for daemons to overwrite environment for ps */
1391 #define DUMMYSIZE       100
1392                 char dummy[DUMMYSIZE];
1393
1394                 (void) memset(dummy, 'x', DUMMYSIZE - 1);
1395                 dummy[DUMMYSIZE - 1] = '\0';
1396
1397                 (void) setenv("inetd_dummy", dummy, 1);
1398         }
1399
1400         for (;;) {
1401                 int n, ctrl = -1;
1402                 fd_set readable;
1403
1404                 if (nsock == 0) {
1405                         Block_Using_Signals(omask);
1406                         while (nsock == 0)
1407                                 sigsuspend(&wait_mask);
1408                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1409                 }
1410
1411                 readable = allsock;
1412                 n = select(maxsock + 1, &readable, NULL, NULL, NULL);
1413                 if (n <= 0) {
1414                         if (n < 0 && errno != EINTR) {
1415                                 bb_perror_msg("select");
1416                                 sleep(1);
1417                         }
1418                         continue;
1419                 }
1420
1421                 for (sep = servtab; n && sep; sep = sep->se_next) {
1422                         if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1423                                 continue;
1424
1425                         n--;
1426                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
1427                                 ctrl = accept(sep->se_fd, NULL, NULL);
1428                                 if (ctrl < 0) {
1429                                         if (errno == EINTR)
1430                                                 continue;
1431                                         bb_perror_msg("accept (for %s)", sep->se_service);
1432                                         continue;
1433                                 }
1434                                 if (sep->se_family == AF_INET && sep->se_socktype == SOCK_STREAM) {
1435                                         struct sockaddr_in peer;
1436                                         socklen_t plen = sizeof(peer);
1437
1438                                         if (getpeername(ctrl, (struct sockaddr *) &peer, &plen) < 0) {
1439                                                 bb_error_msg("cannot getpeername");
1440                                                 close(ctrl);
1441                                                 continue;
1442                                         }
1443                                         if (ntohs(peer.sin_port) == 20) {
1444                                                 /* XXX ftp bounce */
1445                                                 close(ctrl);
1446                                                 continue;
1447                                         }
1448                                 }
1449                         } else
1450                                 ctrl = sep->se_fd;
1451
1452                         Block_Using_Signals(omask);
1453                         pid = 0;
1454 #ifdef INETD_FEATURE_ENABLED
1455                         if (sep->se_bi == 0 || sep->se_bi->bi_fork)
1456 #endif
1457                         {
1458                                 if (sep->se_count++ == 0)
1459                                         (void) gettimeofday(&sep->se_time, NULL);
1460                                 else if (toomany > 0 && sep->se_count >= sep->se_max) {
1461                                         struct timeval now;
1462
1463                                         (void) gettimeofday(&now, NULL);
1464                                         if (now.tv_sec - sep->se_time.tv_sec > CNT_INTVL) {
1465                                                 sep->se_time = now;
1466                                                 sep->se_count = 1;
1467                                         } else {
1468                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1469                                                         close(ctrl);
1470                                                 if (sep->se_family == AF_INET &&
1471                                                           ntohs(sep->se_ctrladdr_in.sin_port) >= IPPORT_RESERVED) {
1472                                                         /*
1473                                                          * Cannot close it -- there are
1474                                                          * thieves on the system.
1475                                                          * Simply ignore the connection.
1476                                                          */
1477                                                         --sep->se_count;
1478                                                         continue;
1479                                                 }
1480                                                 bb_error_msg("%s/%s server failing (looping), service terminated",
1481                                                               sep->se_service, sep->se_proto);
1482                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1483                                                         close(ctrl);
1484                                                 FD_CLR(sep->se_fd, &allsock);
1485                                                 (void) close(sep->se_fd);
1486                                                 sep->se_fd = -1;
1487                                                 sep->se_count = 0;
1488                                                 nsock--;
1489                                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1490                                                 if (!timingout) {
1491                                                         timingout = 1;
1492                                                         alarm(RETRYTIME);
1493                                                 }
1494                                                 continue;
1495                                         }
1496                                 }
1497                                 pid = fork();
1498                         }
1499                         if (pid < 0) {
1500                                 bb_perror_msg("fork");
1501                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1502                                         close(ctrl);
1503                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1504                                 sleep(1);
1505                                 continue;
1506                         }
1507                         if (pid && sep->se_wait) {
1508                                 sep->se_wait = pid;
1509                                 FD_CLR(sep->se_fd, &allsock);
1510                                 nsock--;
1511                         }
1512                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1513                         if (pid == 0) {
1514 #ifdef INETD_FEATURE_ENABLED
1515                                 if (sep->se_bi) {
1516                                         (*sep->se_bi->bi_fn)(ctrl, sep);
1517                                 } else
1518 #endif
1519                                 {
1520                                         pwd = getpwnam(sep->se_user);
1521                                         if (pwd == NULL) {
1522                                                 bb_error_msg("getpwnam: %s: no such user", sep->se_user);
1523                                                 goto do_exit1;
1524                                         }
1525                                         if (setsid() < 0)
1526                                                 bb_perror_msg("%s: setsid", sep->se_service);
1527                                         if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1528                                                 bb_error_msg("getgrnam: %s: no such group", sep->se_group);
1529                                                 goto do_exit1;
1530                                         }
1531                                         if (uid != 0) {
1532                                                 /* a user running private inetd */
1533                                                 if (uid != pwd->pw_uid)
1534                                                         _exit(1);
1535                                         } else if (pwd->pw_uid) {
1536                                                 if (sep->se_group)
1537                                                         pwd->pw_gid = grp->gr_gid;
1538                                                 xsetgid((gid_t) pwd->pw_gid);
1539                                                 initgroups(pwd->pw_name, pwd->pw_gid);
1540                                                 xsetuid((uid_t) pwd->pw_uid);
1541                                         } else if (sep->se_group) {
1542                                                 xsetgid(grp->gr_gid);
1543                                                 setgroups(1, &grp->gr_gid);
1544                                         }
1545                                         dup2(ctrl, 0);
1546                                         if (ctrl) close(ctrl);
1547                                         dup2(0, 1);
1548                                         dup2(0, 2);
1549                                         if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1550                                                 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1551                                                         bb_perror_msg("setrlimit");
1552                                         closelog();
1553                                         for (tmpint = rlim_ofile_cur - 1; --tmpint > 2;)
1554                                                 (void) close(tmpint);
1555                                         sigaction(SIGPIPE, &sapipe, NULL);
1556                                         execv(sep->se_server, sep->se_argv);
1557                                         bb_perror_msg("execv %s", sep->se_server);
1558  do_exit1:
1559                                         if (sep->se_socktype != SOCK_STREAM)
1560                                                 recv(0, buf, sizeof(buf), 0);
1561                                         _exit(1);
1562                                 }
1563                         }
1564                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1565                                 close(ctrl);
1566                 } /* for (sep = servtab...) */
1567         } /* for (;;) */
1568 }
1569
1570 /*
1571  * Internet services provided internally by inetd:
1572  */
1573 #define BUFSIZE 4096
1574
1575 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
1576         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN || \
1577         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1578 static int dg_badinput(struct sockaddr_in *dg_sin)
1579 {
1580         if (ntohs(dg_sin->sin_port) < IPPORT_RESERVED)
1581                 return 1;
1582         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST))
1583                 return 1;
1584         /* XXX compare against broadcast addresses in SIOCGIFCONF list? */
1585         return 0;
1586 }
1587 #endif
1588
1589 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1590 /* Echo service -- echo data back */
1591 /* ARGSUSED */
1592 static void
1593 echo_stream(int s, servtab_t *sep)
1594 {
1595         char buffer[BUFSIZE];
1596         int i;
1597
1598         inetd_setproctitle(sep->se_service, s);
1599         while (1) {
1600                 i = read(s, buffer, sizeof(buffer));
1601                 if (i <= 0) break;
1602                 /* FIXME: this isnt correct - safe_write()? */
1603                 if (write(s, buffer, i) <= 0) break;
1604         }
1605         exit(0);
1606 }
1607
1608 /* Echo service -- echo data back */
1609 /* ARGSUSED */
1610 static void
1611 echo_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1612 {
1613         char buffer[BUFSIZE];
1614         int i;
1615         socklen_t size;
1616         /* struct sockaddr_storage ss; */
1617         struct sockaddr sa;
1618
1619         size = sizeof(sa);
1620         i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size);
1621         if (i < 0)
1622                 return;
1623         if (dg_badinput((struct sockaddr_in *) &sa))
1624                 return;
1625         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1626 }
1627 #endif  /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1628
1629 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1630 /* Discard service -- ignore data */
1631 /* ARGSUSED */
1632 static void
1633 discard_stream(int s, servtab_t *sep)
1634 {
1635         char buffer[BUFSIZE];
1636
1637         inetd_setproctitle(sep->se_service, s);
1638         while (1) {
1639                 if (safe_read(s, buffer, sizeof(buffer)) <= 0)
1640                         exit(0);
1641         }
1642 }
1643
1644 /* Discard service -- ignore data */
1645 /* ARGSUSED */
1646 static void
1647 discard_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1648 {
1649         char buffer[BUFSIZE];
1650
1651         (void) read(s, buffer, sizeof(buffer));
1652 }
1653 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1654
1655
1656 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1657 #define LINESIZ 72
1658
1659 static void
1660 initring(void)
1661 {
1662         int i;
1663
1664         endring = ring;
1665         for (i = 0; i <= 128; ++i)
1666                 if (isprint(i))
1667                         *endring++ = i;
1668 }
1669
1670 /* Character generator */
1671 /* ARGSUSED */
1672 static void
1673 chargen_stream(int s, servtab_t *sep)
1674 {
1675         char *rs;
1676         int len;
1677         char text[LINESIZ + 2];
1678
1679         inetd_setproctitle(sep->se_service, s);
1680
1681         if (!endring) {
1682                 initring();
1683                 rs = ring;
1684         }
1685
1686         text[LINESIZ] = '\r';
1687         text[LINESIZ + 1] = '\n';
1688         rs = ring;
1689         for (;;) {
1690                 len = endring - rs;
1691                 if (len >= LINESIZ)
1692                         memmove(text, rs, LINESIZ);
1693                 else {
1694                         memmove(text, rs, len);
1695                         memmove(text + len, ring, LINESIZ - len);
1696                 }
1697                 if (++rs == endring)
1698                         rs = ring;
1699                 if (write(s, text, sizeof(text)) != sizeof(text))
1700                         break;
1701         }
1702         exit(0);
1703 }
1704
1705 /* Character generator */
1706 /* ARGSUSED */
1707 static void
1708 chargen_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1709 {
1710         /* struct sockaddr_storage ss; */
1711         struct sockaddr sa;
1712         int len;
1713         char text[LINESIZ + 2];
1714         socklen_t size;
1715
1716         if (!endring) {
1717                 initring();
1718                 ringpos = ring;
1719         }
1720
1721         size = sizeof(sa);
1722         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1723                 return;
1724         if (dg_badinput((struct sockaddr_in *) &sa))
1725                 return;
1726
1727         len = endring - ringpos;
1728         if (len >= LINESIZ)
1729                 memmove(text, ringpos, LINESIZ);
1730         else {
1731                 memmove(text, ringpos, len);
1732                 memmove(text + len, ring, LINESIZ - len);
1733         }
1734         if (++ringpos == endring)
1735                 ringpos = ring;
1736         text[LINESIZ] = '\r';
1737         text[LINESIZ + 1] = '\n';
1738         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1739 }
1740 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1741
1742
1743 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1744 /*
1745  * Return a machine readable date and time, in the form of the
1746  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1747  * returns the number of seconds since midnight, Jan 1, 1970,
1748  * we must add 2208988800 seconds to this figure to make up for
1749  * some seventy years Bell Labs was asleep.
1750  */
1751
1752 static unsigned machtime(void)
1753 {
1754         struct timeval tv;
1755
1756         if (gettimeofday(&tv, NULL) < 0) {
1757                 fprintf(stderr, "Unable to get time of day\n");
1758                 return 0L;
1759         }
1760         return htonl((unsigned) tv.tv_sec + 2208988800UL);
1761 }
1762
1763 /* ARGSUSED */
1764 static void
1765 machtime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1766 {
1767         unsigned result;
1768
1769         result = machtime();
1770         (void) write(s, (char *) &result, sizeof(result));
1771 }
1772
1773 /* ARGSUSED */
1774 static void
1775 machtime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1776 {
1777         unsigned result;
1778         /* struct sockaddr_storage ss; */
1779         struct sockaddr sa;
1780         struct sockaddr_in *dg_sin;
1781         socklen_t size;
1782
1783         size = sizeof(sa);
1784         if (recvfrom(s, (char *) &result, sizeof(result), 0, &sa, &size) < 0)
1785                 return;
1786         /* if (dg_badinput((struct sockaddr *)&ss)) */
1787         dg_sin = (struct sockaddr_in *) &sa;
1788         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST) ||
1789                         ntohs(dg_sin->sin_port) < IPPORT_RESERVED / 2)
1790                 return;
1791         result = machtime();
1792         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1793 }
1794 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1795
1796
1797 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1798 /* Return human-readable time of day */
1799 /* ARGSUSED */
1800 static void daytime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1801 {
1802         char buffer[32];
1803         time_t t;
1804
1805         t = time(NULL);
1806
1807 // fdprintf instead?
1808         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1809         (void) write(s, buffer, strlen(buffer));
1810 }
1811
1812 /* Return human-readable time of day */
1813 /* ARGSUSED */
1814 void
1815 daytime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1816 {
1817         char buffer[256];
1818         time_t t;
1819         /* struct sockaddr_storage ss; */
1820         struct sockaddr sa;
1821         socklen_t size;
1822
1823         t = time(NULL);
1824
1825         size = sizeof(sa);
1826         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1827                 return;
1828         if (dg_badinput((struct sockaddr_in *) &sa))
1829                 return;
1830         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1831         (void) sendto(s, buffer, strlen(buffer), 0, &sa, sizeof(sa));
1832 }
1833 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */