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 struct servtab_t {
 210         /* The most frequently referenced one: */
 211         int se_fd;                            /* open descriptor */
 212         /* NB: 'biggest fields last' saves on code size (~250 bytes) */
 213         char *se_hostaddr;                    /* host address to listen on */
 214         char *se_service;                     /* name of service */
 215         char *se_proto;                       /* protocol used */
 216 #if ENABLE_FEATURE_INETD_RPC
 217         int se_rpcprog;                       /* rpc program number */
 218         int se_rpcversl;                      /* rpc program lowest version */
 219         int se_rpcversh;                      /* rpc program highest version */
 220 #define isrpcservice(sep)       ((sep)->se_rpcversl != 0)
 221 #else
 222 #define isrpcservice(sep)       0
 223 #endif
 224         pid_t se_wait;                        /* single threaded server */
 225         socktype_t se_socktype;               /* type of socket to use */
 226         family_t se_family;                   /* address family */
 227         smallint 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         int se_ctrladdr_size;
 234         int se_max;                           /* max # of instances of this service */
 235         int se_count;                         /* number started since se_time */
 236         struct servtab_t *se_next;
 237         struct timeval se_time;               /* start of se_count */
 238         char *se_server;                      /* server program */
 239 #define MAXARGV 20
 240         char *se_argv[MAXARGV + 1];           /* program arguments */
 241         union {
 242                 struct sockaddr se_un_ctrladdr;
 243                 struct sockaddr_in se_un_ctrladdr_in;
 244 #if ENABLE_FEATURE_IPV6
 245                 struct sockaddr_in6 se_un_ctrladdr_in6;
 246 #endif
 247                 struct sockaddr_un se_un_ctrladdr_un;
 248         } se_un;                              /* bound address */
 249 #define se_ctrladdr     se_un.se_un_ctrladdr
 250 #define se_ctrladdr_in  se_un.se_un_ctrladdr_in
 251 #define se_ctrladdr_in6 se_un.se_un_ctrladdr_in6
 252 #define se_ctrladdr_un  se_un.se_un_ctrladdr_un
 253 } servtab_t;
 254
 255 #ifdef INETD_FEATURE_ENABLED
 256 struct builtin {
 257         const char *bi_service;               /* internally provided service name */
 258         socktype_t bi_socktype;               /* type of socket supported */
 259         uint8_t bi_fork;                      /* 1 if should fork before call */
 260 // Commented since it is always 0
 261 //      uint8_t bi_wait;                      /* 1 if should wait for child */
 262         void (*bi_fn) (int, servtab_t *);
 263 };
 264
 265                 /* Echo received data */
 266 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
 267 static void echo_stream(int, servtab_t *);
 268 static void echo_dg(int, servtab_t *);
 269 #endif
 270                 /* Internet /dev/null */
 271 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
 272 static void discard_stream(int, servtab_t *);
 273 static void discard_dg(int, servtab_t *);
 274 #endif
 275                 /* Return 32 bit time since 1900 */
 276 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
 277 static void machtime_stream(int, servtab_t *);
 278 static void machtime_dg(int, servtab_t *);
 279 #endif
 280                 /* Return human-readable time */
 281 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
 282 static void daytime_stream(int, servtab_t *);
 283 static void daytime_dg(int, servtab_t *);
 284 #endif
 285                 /* Familiar character generator */
 286 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 287 static void chargen_stream(int, servtab_t *);
 288 static void chargen_dg(int, servtab_t *);
 289 #endif
 290
 291 static const struct builtin builtins[] = {
 292 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
 293         /* Echo received data */
 294         {"echo", SOCK_STREAM, 1, echo_stream,},
 295         {"echo", SOCK_DGRAM, 0, echo_dg,},
 296 #endif
 297 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
 298         /* Internet /dev/null */
 299         {"discard", SOCK_STREAM, 1, discard_stream,},
 300         {"discard", SOCK_DGRAM, 0, discard_dg,},
 301 #endif
 302 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
 303         /* Return 32 bit time since 1900 */
 304         {"time", SOCK_STREAM, 0, machtime_stream,},
 305         {"time", SOCK_DGRAM, 0, machtime_dg,},
 306 #endif
 307 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
 308         /* Return human-readable time */
 309         {"daytime", SOCK_STREAM, 0, daytime_stream,},
 310         {"daytime", SOCK_DGRAM, 0, daytime_dg,},
 311 #endif
 312 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 313         /* Familiar character generator */
 314         {"chargen", SOCK_STREAM, 1, chargen_stream,},
 315         {"chargen", SOCK_DGRAM, 0, chargen_dg,},
 316 #endif
 317         { /* zero filled */ }
 318 };
 319 #endif /* INETD_FEATURE_ENABLED */
 320
 321 struct globals {
 322         rlim_t rlim_ofile_cur;
 323         struct rlimit rlim_ofile;
 324         servtab_t *servtab;
 325         int global_queuelen;
 326         int nsock;
 327         int maxsock;
 328         int toomany;
 329         int timingout;
 330         struct servent *sp;
 331         uid_t uid;
 332         const char *config_filename;
 333         FILE *fconfig;
 334         char *defhost;
 335 #ifdef INETD_SETPROCTITLE
 336         char **Argv;
 337         char *LastArg;
 338 #endif
 339 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
 340         char *endring;
 341         char *ringpos;
 342         char ring[128];
 343 #endif
 344         fd_set allsock;
 345         /* Used only in nextline() */
 346         char line[80];          /* at least 80, see LINE_SIZE */
 347 };
 348 #define G (*(struct globals*)&bb_common_bufsiz1)
 349 enum { LINE_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line) };
 350 struct BUG_G_too_big {
 351         char BUG_G_too_big[sizeof(G) <= COMMON_BUFSIZE ? 1 : -1];
 352 };
 353 #define rlim_ofile_cur  (G.rlim_ofile_cur )
 354 #define rlim_ofile      (G.rlim_ofile     )
 355 #define servtab         (G.servtab        )
 356 #define global_queuelen (G.global_queuelen)
 357 #define nsock           (G.nsock          )
 358 #define maxsock         (G.maxsock        )
 359 #define toomany         (G.toomany        )
 360 #define timingout       (G.timingout      )
 361 #define sp              (G.sp             )
 362 #define uid             (G.uid            )
 363 #define config_filename (G.config_filename)
 364 #define fconfig         (G.fconfig        )
 365 #define defhost         (G.defhost        )
 366 #define Argv            (G.Argv           )
 367 #define LastArg         (G.LastArg        )
 368 #define endring         (G.endring        )
 369 #define ringpos         (G.ringpos        )
 370 #define ring            (G.ring           )
 371 #define allsock         (G.allsock        )
 372 #define line            (G.line           )
 373 #define INIT_G() do { \
 374         rlim_ofile_cur = OPEN_MAX; \
 375         global_queuelen = 128; \
 376         config_filename = "/etc/inetd.conf"; \
 377 } while (0)
 378
 379 /* xstrdup(NULL) returns NULL, but this one
 380  * will return newly-allocated "" if called with NULL arg
 381  * TODO: audit whether this makes any real difference
 382  */
 383 static char *xxstrdup(char *cp)
 384 {
 385         return xstrdup(cp ? cp : "");
 386 }
 387
 388 static int setconfig(void)
 389 {
 390         free(defhost);
 391         defhost = xstrdup("*");
 392         if (fconfig != NULL) {
 393                 fseek(fconfig, 0L, SEEK_SET);
 394                 return 1;
 395         }
 396         fconfig = fopen(config_filename, "r");
 397         return (fconfig != NULL);
 398 }
 399
 400 static void endconfig(void)
 401 {
 402         if (fconfig) {
 403                 (void) fclose(fconfig);
 404                 fconfig = NULL;
 405         }
 406         free(defhost);
 407         defhost = 0;
 408 }
 409
 410 #if ENABLE_FEATURE_INETD_RPC
 411 static void register_rpc(servtab_t *sep)
 412 {
 413         int n;
 414         struct sockaddr_in ir_sin;
 415         struct protoent *pp;
 416         socklen_t size;
 417
 418         pp = getprotobyname(sep->se_proto + 4);
 419         if (pp == NULL) {
 420                 bb_perror_msg("%s: getproto", sep->se_proto);
 421                 return;
 422         }
 423         size = sizeof ir_sin;
 424         if (getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, &size) < 0) {
 425                 bb_perror_msg("%s/%s: getsockname",
 426                                 sep->se_service, sep->se_proto);
 427                 return;
 428         }
 429
 430         for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
 431                 (void) pmap_unset(sep->se_rpcprog, n);
 432                 if (!pmap_set(sep->se_rpcprog, n, pp->p_proto, ntohs(ir_sin.sin_port)))
 433                         bb_perror_msg("%s %s: pmap_set: %u %u %u %u",
 434                                         sep->se_service, sep->se_proto,
 435                                         sep->se_rpcprog, n, pp->p_proto, ntohs(ir_sin.sin_port));
 436         }
 437 }
 438
 439 static void unregister_rpc(servtab_t *sep)
 440 {
 441         int n;
 442
 443         for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
 444                 if (!pmap_unset(sep->se_rpcprog, n))
 445                         bb_error_msg("pmap_unset(%u, %u)", sep->se_rpcprog, n);
 446         }
 447 }
 448 #endif /* FEATURE_INETD_RPC */
 449
 450 static void freeconfig(servtab_t *cp)
 451 {
 452         int i;
 453
 454         free(cp->se_hostaddr);
 455         free(cp->se_service);
 456         free(cp->se_proto);
 457         free(cp->se_user);
 458         free(cp->se_group);
 459         free(cp->se_server);
 460         for (i = 0; i < MAXARGV; i++)
 461                 free(cp->se_argv[i]);
 462 }
 463
 464 static int bump_nofile(void)
 465 {
 466 #define FD_CHUNK        32
 467
 468         struct rlimit rl;
 469
 470         if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
 471                 bb_perror_msg("getrlimit");
 472                 return -1;
 473         }
 474         rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
 475         rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
 476         if (rl.rlim_cur <= rlim_ofile_cur) {
 477                 bb_error_msg("bump_nofile: cannot extend file limit, max = %d",
 478                                                 (int) rl.rlim_cur);
 479                 return -1;
 480         }
 481
 482         if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
 483                 bb_perror_msg("setrlimit");
 484                 return -1;
 485         }
 486
 487         rlim_ofile_cur = rl.rlim_cur;
 488         return 0;
 489 }
 490
 491 static void setup(servtab_t *sep)
 492 {
 493         int r;
 494
 495         sep->se_fd = socket(sep->se_family, sep->se_socktype, 0);
 496         if (sep->se_fd < 0) {
 497                 bb_perror_msg("%s/%s: socket", sep->se_service, sep->se_proto);
 498                 return;
 499         }
 500         setsockopt_reuseaddr(sep->se_fd);
 501
 502 #if ENABLE_FEATURE_INETD_RPC
 503         if (isrpcservice(sep)) {
 504                 struct passwd *pwd;
 505
 506                 /*
 507                  * for RPC services, attempt to use a reserved port
 508                  * if they are going to be running as root.
 509                  *
 510                  * Also, zero out the port for all RPC services; let bind()
 511                  * find one.
 512                  */
 513                 sep->se_ctrladdr_in.sin_port = 0;
 514                 if (sep->se_user && (pwd = getpwnam(sep->se_user)) &&
 515                                 pwd->pw_uid == 0 && uid == 0)
 516                         r = bindresvport(sep->se_fd, &sep->se_ctrladdr_in);
 517                 else {
 518                         r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 519                         if (r == 0) {
 520                                 socklen_t len = sep->se_ctrladdr_size;
 521                                 int saveerrno = errno;
 522
 523                                 /* update se_ctrladdr_in.sin_port */
 524                                 r = getsockname(sep->se_fd, &sep->se_ctrladdr, &len);
 525                                 if (r <= 0)
 526                                         errno = saveerrno;
 527                         }
 528                 }
 529         } else
 530 #endif
 531                 r = bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size);
 532         if (r < 0) {
 533                 bb_perror_msg("%s/%s (%d): bind",
 534                                 sep->se_service, sep->se_proto, sep->se_ctrladdr.sa_family);
 535                 close(sep->se_fd);
 536                 sep->se_fd = -1;
 537                 if (!timingout) {
 538                         timingout = 1;
 539                         alarm(RETRYTIME);
 540                 }
 541                 return;
 542         }
 543         if (sep->se_socktype == SOCK_STREAM)
 544                 listen(sep->se_fd, global_queuelen);
 545
 546         FD_SET(sep->se_fd, &allsock);
 547         nsock++;
 548         if (sep->se_fd > maxsock) {
 549                 maxsock = sep->se_fd;
 550                 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
 551                         bump_nofile();
 552         }
 553 }
 554
 555 static char *nextline(void)
 556 {
 557         char *cp;
 558
 559         if (fgets(line, LINE_SIZE, fconfig) == NULL)
 560                 return NULL;
 561         cp = strchr(line, '\n');
 562         if (cp)
 563                 *cp = '\0';
 564         return line;
 565 }
 566
 567 static char *skip(char **cpp) /* int report; */
 568 {
 569         char *cp = *cpp;
 570         char *start;
 571
 572 /* erp: */
 573         if (cp == NULL) {
 574                 /* if (report) */
 575                 /* bb_error_msg("syntax error in inetd config file"); */
 576                 return NULL;
 577         }
 578
 579  again:
 580         while (*cp == ' ' || *cp == '\t')
 581                 cp++;
 582         if (*cp == '\0') {
 583                 int c = getc(fconfig);
 584                 ungetc(c, fconfig);
 585                 if (c == ' ' || c == '\t') {
 586                         cp = nextline();
 587                         if (cp)
 588                                 goto again;
 589                 }
 590                 *cpp = NULL;
 591                 return NULL;
 592         }
 593         start = cp;
 594         while (*cp && *cp != ' ' && *cp != '\t')
 595                 cp++;
 596         if (*cp != '\0')
 597                 *cp++ = '\0';
 598
 599         *cpp = cp;
 600         return start;
 601 }
 602
 603 static servtab_t *new_servtab(void)
 604 {
 605         return xzalloc(sizeof(servtab_t));
 606 }
 607
 608 static servtab_t *dupconfig(servtab_t *sep)
 609 {
 610         servtab_t *newtab;
 611         int argc;
 612
 613         newtab = new_servtab();
 614         newtab->se_service = xstrdup(sep->se_service);
 615         newtab->se_socktype = sep->se_socktype;
 616         newtab->se_family = sep->se_family;
 617         newtab->se_proto = xstrdup(sep->se_proto);
 618 #if ENABLE_FEATURE_INETD_RPC
 619         newtab->se_rpcprog = sep->se_rpcprog;
 620         newtab->se_rpcversl = sep->se_rpcversl;
 621         newtab->se_rpcversh = sep->se_rpcversh;
 622 #endif
 623         newtab->se_wait = sep->se_wait;
 624         newtab->se_user = xstrdup(sep->se_user);
 625         newtab->se_group = xstrdup(sep->se_group);
 626 #ifdef INETD_FEATURE_ENABLED
 627         newtab->se_bi = sep->se_bi;
 628 #endif
 629         newtab->se_server = xstrdup(sep->se_server);
 630
 631         for (argc = 0; argc <= MAXARGV; argc++)
 632                 newtab->se_argv[argc] = xstrdup(sep->se_argv[argc]);
 633         newtab->se_max = sep->se_max;
 634
 635         return newtab;
 636 }
 637
 638 static servtab_t *getconfigent(void)
 639 {
 640         servtab_t *sep;
 641         int argc;
 642         char *cp, *arg;
 643         char *hostdelim;
 644         servtab_t *nsep;
 645         servtab_t *psep;
 646
 647         sep = new_servtab();
 648
 649  more:
 650         while ((cp = nextline()) && *cp == '#')
 651                 continue; /* skip comment lines */
 652         if (cp == NULL) {
 653                 free(sep);
 654                 return NULL;
 655         }
 656
 657         arg = skip(&cp);
 658         if (arg == NULL) {
 659                 /* A blank line. */
 660                 goto more;
 661         }
 662
 663         /* Check for a host name. */
 664         hostdelim = strrchr(arg, ':');
 665         if (hostdelim) {
 666                 *hostdelim = '\0';
 667                 sep->se_hostaddr = xstrdup(arg);
 668                 arg = hostdelim + 1;
 669                 /*
 670                  * If the line is of the form `host:', then just change the
 671                  * default host for the following lines.
 672                  */
 673                 if (*arg == '\0') {
 674                         arg = skip(&cp);
 675                         if (cp == NULL) {
 676                                 free(defhost);
 677                                 defhost = sep->se_hostaddr;
 678                                 goto more;
 679                         }
 680                 }
 681         } else
 682                 sep->se_hostaddr = xxstrdup(defhost);
 683
 684         sep->se_service = xxstrdup(arg);
 685         arg = skip(&cp);
 686
 687         {
 688                 static int8_t SOCK_xxx[] ALIGN1 = {
 689                         -1,
 690                         SOCK_STREAM, SOCK_DGRAM, SOCK_RDM,
 691                         SOCK_SEQPACKET, SOCK_RAW
 692                 };
 693                 sep->se_socktype = SOCK_xxx[1 + index_in_strings(
 694                         "stream""\0" "dgram""\0" "rdm""\0"
 695                         "seqpacket""\0" "raw""\0"
 696                         , arg)];
 697         }
 698
 699         sep->se_proto = xxstrdup(skip(&cp));
 700
 701         if (strcmp(sep->se_proto, "unix") == 0) {
 702                 sep->se_family = AF_UNIX;
 703         } else {
 704                 sep->se_family = AF_INET;
 705                 if (sep->se_proto[strlen(sep->se_proto) - 1] == '6')
 706 #if ENABLE_FEATURE_IPV6
 707                         sep->se_family = AF_INET6;
 708 #else
 709                         bb_error_msg("%s: IPV6 not supported", sep->se_proto);
 710 #endif
 711                 if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
 712 #if ENABLE_FEATURE_INETD_RPC
 713                         char *p, *ccp;
 714                         long l;
 715
 716                         p = strchr(sep->se_service, '/');
 717                         if (p == 0) {
 718                                 bb_error_msg("%s: no rpc version", sep->se_service);
 719                                 goto more;
 720                         }
 721                         *p++ = '\0';
 722                         l = strtol(p, &ccp, 0);
 723                         if (ccp == p || l < 0 || l > INT_MAX) {
 724  badafterall:
 725                                 bb_error_msg("%s/%s: bad rpc version", sep->se_service, p);
 726                                 goto more;
 727                         }
 728                         sep->se_rpcversl = sep->se_rpcversh = l;
 729                         if (*ccp == '-') {
 730                                 p = ccp + 1;
 731                                 l = strtol(p, &ccp, 0);
 732                                 if (ccp == p || l < 0 || l > INT_MAX || l < sep->se_rpcversl || *ccp)
 733                                         goto badafterall;
 734                                 sep->se_rpcversh = l;
 735                         } else if (*ccp != '\0')
 736                                 goto badafterall;
 737 #else
 738                         bb_error_msg("%s: rpc services not supported", sep->se_service);
 739 #endif
 740                 }
 741         }
 742         arg = skip(&cp);
 743         if (arg == NULL)
 744                 goto more;
 745
 746         {
 747                 char *s = strchr(arg, '.');
 748                 if (s) {
 749                         *s++ = '\0';
 750                         sep->se_max = xatoi(s);
 751                 } else
 752                         sep->se_max = toomany;
 753         }
 754         sep->se_wait = (strcmp(arg, "wait") == 0);
 755         sep->se_user = xxstrdup(skip(&cp));
 756         arg = strchr(sep->se_user, '.');
 757         if (arg == NULL)
 758                 arg = strchr(sep->se_user, ':');
 759         if (arg) {
 760                 *arg++ = '\0';
 761                 sep->se_group = xstrdup(arg);
 762         }
 763
 764         sep->se_server = xxstrdup(skip(&cp));
 765 #ifdef INETD_FEATURE_ENABLED
 766         /* sep->se_bi = NULL; - done by new_servtab() */
 767         if (strcmp(sep->se_server, "internal") == 0) {
 768                 const struct builtin *bi;
 769
 770                 for (bi = builtins; bi->bi_service; bi++)
 771                         if (bi->bi_socktype == sep->se_socktype
 772                          && strcmp(bi->bi_service, sep->se_service) == 0)
 773                                 break;
 774                 if (bi->bi_service == 0) {
 775                         bb_error_msg("internal service %s unknown", sep->se_service);
 776                         goto more;
 777                 }
 778                 sep->se_bi = bi;
 779                 sep->se_wait = 0; /* = bi->bi_wait; - always 0 */
 780         }
 781 #endif
 782         argc = 0;
 783         while ((arg = skip(&cp)) != NULL && argc < MAXARGV) {
 784                 sep->se_argv[argc++] = xxstrdup(arg);
 785         }
 786         /* while (argc <= MAXARGV) */
 787         /*      sep->se_argv[argc++] = NULL; - done by new_servtab() */
 788
 789         /*
 790          * Now that we've processed the entire line, check if the hostname
 791          * specifier was a comma separated list of hostnames. If so
 792          * we'll make new entries for each address.
 793          */
 794         while ((hostdelim = strrchr(sep->se_hostaddr, ',')) != NULL) {
 795                 nsep = dupconfig(sep);
 796
 797                 /*
 798                  * NULL terminate the hostname field of the existing entry,
 799                  * and make a dup for the new entry.
 800                  */
 801                 *hostdelim++ = '\0';
 802                 nsep->se_hostaddr = xstrdup(hostdelim);
 803
 804                 nsep->se_next = sep->se_next;
 805                 sep->se_next = nsep;
 806         }
 807
 808         nsep = sep;
 809         while (nsep != NULL) {
 810                 nsep->se_checked = 1;
 811                 if (nsep->se_family == AF_INET) {
 812                         if (LONE_CHAR(nsep->se_hostaddr, '*'))
 813                                 nsep->se_ctrladdr_in.sin_addr.s_addr = INADDR_ANY;
 814                         else if (!inet_aton(nsep->se_hostaddr, &nsep->se_ctrladdr_in.sin_addr)) {
 815                                 int i;
 816                                 struct hostent *hp;
 817
 818                                 hp = gethostbyname(nsep->se_hostaddr);
 819                                 if (hp == NULL) {
 820                                         bb_error_msg("%s: unknown host", nsep->se_hostaddr);
 821                                         nsep->se_checked = 0;
 822                                         goto skip;
 823                                 }
 824                                 if (hp->h_addrtype != AF_INET) {
 825                                         bb_error_msg("%s: address isn't an Internet "
 826                                                                   "address", nsep->se_hostaddr);
 827                                         nsep->se_checked = 0;
 828                                         goto skip;
 829                                 }
 830                                 i = 1;
 831                                 memmove(&nsep->se_ctrladdr_in.sin_addr,
 832                                                            hp->h_addr_list[0], sizeof(struct in_addr));
 833                                 while (hp->h_addr_list[i] != NULL) {
 834                                         psep = dupconfig(nsep);
 835                                         psep->se_hostaddr = xxstrdup(nsep->se_hostaddr);
 836                                         psep->se_checked = 1;
 837                                         memmove(&psep->se_ctrladdr_in.sin_addr,
 838                                                              hp->h_addr_list[i], sizeof(struct in_addr));
 839                                         psep->se_ctrladdr_size = sizeof(psep->se_ctrladdr_in);
 840                                         i++;
 841                                         /* Prepend to list, don't want to look up */
 842                                         /* its hostname again. */
 843                                         psep->se_next = sep;
 844                                         sep = psep;
 845                                 }
 846                         }
 847                 }
 848 /* XXX BUG?: is this skip: label supposed to remain? */
 849  skip:
 850                 nsep = nsep->se_next;
 851         }
 852
 853         /*
 854          * Finally, free any entries which failed the gethostbyname
 855          * check.
 856          */
 857         psep = NULL;
 858         nsep = sep;
 859         while (nsep != NULL) {
 860                 servtab_t *tsep;
 861
 862                 if (nsep->se_checked == 0) {
 863                         tsep = nsep;
 864                         if (psep == NULL) {
 865                                 sep = nsep->se_next;
 866                                 nsep = sep;
 867                         } else {
 868                                 nsep = nsep->se_next;
 869                                 psep->se_next = nsep;
 870                         }
 871                         freeconfig(tsep);
 872                 } else {
 873                         nsep->se_checked = 0;
 874                         psep = nsep;
 875                         nsep = nsep->se_next;
 876                 }
 877         }
 878
 879         return sep;
 880 }
 881
 882 #define Block_Using_Signals(m) do { \
 883         sigemptyset(&m); \
 884         sigaddset(&m, SIGCHLD); \
 885         sigaddset(&m, SIGHUP); \
 886         sigaddset(&m, SIGALRM); \
 887         sigprocmask(SIG_BLOCK, &m, NULL); \
 888 } while (0)
 889
 890 static servtab_t *enter(servtab_t *cp)
 891 {
 892         servtab_t *sep;
 893         sigset_t omask;
 894
 895         sep = new_servtab();
 896         *sep = *cp;
 897         sep->se_fd = -1;
 898 #if ENABLE_FEATURE_INETD_RPC
 899         sep->se_rpcprog = -1;
 900 #endif
 901         Block_Using_Signals(omask);
 902         sep->se_next = servtab;
 903         servtab = sep;
 904         sigprocmask(SIG_UNBLOCK, &omask, NULL);
 905         return sep;
 906 }
 907
 908 static int matchconf(servtab_t *old, servtab_t *new)
 909 {
 910         if (strcmp(old->se_service, new->se_service) != 0)
 911                 return 0;
 912
 913         if (strcmp(old->se_hostaddr, new->se_hostaddr) != 0)
 914                 return 0;
 915
 916         if (strcmp(old->se_proto, new->se_proto) != 0)
 917                 return 0;
 918
 919         /*
 920          * If the new servtab is bound to a specific address, check that the
 921          * old servtab is bound to the same entry. If the new service is not
 922          * bound to a specific address then the check of se_hostaddr above
 923          * is sufficient.
 924          */
 925
 926         if (old->se_family == AF_INET && new->se_family == AF_INET &&
 927                         memcmp(&old->se_ctrladdr_in.sin_addr,
 928                                         &new->se_ctrladdr_in.sin_addr,
 929                                         sizeof(new->se_ctrladdr_in.sin_addr)) != 0)
 930                 return 0;
 931
 932 #if ENABLE_FEATURE_IPV6
 933         if (old->se_family == AF_INET6 && new->se_family == AF_INET6 &&
 934                         memcmp(&old->se_ctrladdr_in6.sin6_addr,
 935                                         &new->se_ctrladdr_in6.sin6_addr,
 936                                         sizeof(new->se_ctrladdr_in6.sin6_addr)) != 0)
 937                 return 0;
 938 #endif
 939         return 1;
 940 }
 941
 942 static void config(int sig ATTRIBUTE_UNUSED)
 943 {
 944         servtab_t *sep, *cp, **sepp;
 945         sigset_t omask;
 946         size_t n;
 947         char protoname[10];
 948
 949         if (!setconfig()) {
 950                 bb_simple_perror_msg(config_filename);
 951                 return;
 952         }
 953         for (sep = servtab; sep; sep = sep->se_next)
 954                 sep->se_checked = 0;
 955         cp = getconfigent();
 956         while (cp != NULL) {
 957                 for (sep = servtab; sep; sep = sep->se_next)
 958                         if (matchconf(sep, cp))
 959                                 break;
 960
 961                 if (sep != 0) {
 962                         int i;
 963
 964 #define SWAP(type, a, b) do {type c=(type)a; a=(type)b; b=(type)c;} while (0)
 965
 966                         Block_Using_Signals(omask);
 967                         /*
 968                          * sep->se_wait may be holding the pid of a daemon
 969                          * that we're waiting for.  If so, don't overwrite
 970                          * it unless the config file explicitly says don't
 971                          * wait.
 972                          */
 973                         if (
 974 #ifdef INETD_FEATURE_ENABLED
 975                                 cp->se_bi == 0 &&
 976 #endif
 977                                 (sep->se_wait == 1 || cp->se_wait == 0))
 978                                 sep->se_wait = cp->se_wait;
 979                         SWAP(int, cp->se_max, sep->se_max);
 980                         SWAP(char *, sep->se_user, cp->se_user);
 981                         SWAP(char *, sep->se_group, cp->se_group);
 982                         SWAP(char *, sep->se_server, cp->se_server);
 983                         for (i = 0; i < MAXARGV; i++)
 984                                 SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
 985 #undef SWAP
 986
 987 #if ENABLE_FEATURE_INETD_RPC
 988                         if (isrpcservice(sep))
 989                                 unregister_rpc(sep);
 990                         sep->se_rpcversl = cp->se_rpcversl;
 991                         sep->se_rpcversh = cp->se_rpcversh;
 992 #endif
 993                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
 994                         freeconfig(cp);
 995                 } else {
 996                         sep = enter(cp);
 997                 }
 998                 sep->se_checked = 1;
 999
1000                 switch (sep->se_family) {
1001                 case AF_UNIX:
1002                         if (sep->se_fd != -1)
1003                                 break;
1004                         (void) unlink(sep->se_service);
1005                         n = strlen(sep->se_service);
1006                         if (n > sizeof sep->se_ctrladdr_un.sun_path - 1)
1007                                 n = sizeof sep->se_ctrladdr_un.sun_path - 1;
1008                         safe_strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n + 1);
1009                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
1010                         sep->se_ctrladdr_size = n + sizeof sep->se_ctrladdr_un.sun_family;
1011                         setup(sep);
1012                         break;
1013                 case AF_INET:
1014                         sep->se_ctrladdr_in.sin_family = AF_INET;
1015                         /* se_ctrladdr_in was set in getconfigent */
1016                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
1017
1018 #if ENABLE_FEATURE_INETD_RPC
1019                         if (isrpcservice(sep)) {
1020                                 struct rpcent *rp;
1021                                 // FIXME: atoi_or_else(str, 0) would be handy here
1022                                 sep->se_rpcprog = atoi(sep->se_service);
1023                                 if (sep->se_rpcprog == 0) {
1024                                         rp = getrpcbyname(sep->se_service);
1025                                         if (rp == 0) {
1026                                                 bb_error_msg("%s: unknown rpc service", sep->se_service);
1027                                                 goto serv_unknown;
1028                                         }
1029                                         sep->se_rpcprog = rp->r_number;
1030                                 }
1031                                 if (sep->se_fd == -1)
1032                                         setup(sep);
1033                                 if (sep->se_fd != -1)
1034                                         register_rpc(sep);
1035                         } else
1036 #endif
1037                         {
1038                                 uint16_t port = htons(atoi(sep->se_service));
1039                                 // FIXME: atoi_or_else(str, 0) would be handy here
1040                                 if (!port) {
1041                                          /*XXX*/ strncpy(protoname, sep->se_proto, sizeof(protoname));
1042                                         if (isdigit(protoname[strlen(protoname) - 1]))
1043                                                 protoname[strlen(protoname) - 1] = '\0';
1044                                         sp = getservbyname(sep->se_service, protoname);
1045                                         if (sp == 0) {
1046                                                 bb_error_msg("%s/%s: unknown service",
1047                                                                 sep->se_service, sep->se_proto);
1048                                                 goto serv_unknown;
1049                                         }
1050                                         port = sp->s_port;
1051                                 }
1052                                 if (port != sep->se_ctrladdr_in.sin_port) {
1053                                         sep->se_ctrladdr_in.sin_port = port;
1054                                         if (sep->se_fd != -1) {
1055                                                 FD_CLR(sep->se_fd, &allsock);
1056                                                 nsock--;
1057                                                 (void) close(sep->se_fd);
1058                                         }
1059                                         sep->se_fd = -1;
1060                                 }
1061                                 if (sep->se_fd == -1)
1062                                         setup(sep);
1063                         }
1064                         break;
1065 #if ENABLE_FEATURE_IPV6
1066                 case AF_INET6:
1067                         sep->se_ctrladdr_in6.sin6_family = AF_INET6;
1068                         /* se_ctrladdr_in was set in getconfigent */
1069                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in6;
1070
1071 #if ENABLE_FEATURE_INETD_RPC
1072                         if (isrpcservice(sep)) {
1073                                 struct rpcent *rp;
1074
1075                                 sep->se_rpcprog = atoi(sep->se_service);
1076                                 if (sep->se_rpcprog == 0) {
1077                                         rp = getrpcbyname(sep->se_service);
1078                                         if (rp == 0) {
1079                                                 bb_error_msg("%s: unknown rpc service", sep->se_service);
1080                                                 goto serv_unknown;
1081                                         }
1082                                         sep->se_rpcprog = rp->r_number;
1083                                 }
1084                                 if (sep->se_fd == -1)
1085                                         setup(sep);
1086                                 if (sep->se_fd != -1)
1087                                         register_rpc(sep);
1088                         } else
1089 #endif
1090                         {
1091                                 uint16_t port = htons(atoi(sep->se_service));
1092
1093                                 if (!port) {
1094                                          /*XXX*/ strncpy(protoname, sep->se_proto, sizeof(protoname));
1095                                         if (isdigit(protoname[strlen(protoname) - 1]))
1096                                                 protoname[strlen(protoname) - 1] = '\0';
1097                                         sp = getservbyname(sep->se_service, protoname);
1098                                         if (sp == 0) {
1099                                                 bb_error_msg("%s/%s: unknown service",
1100                                                                 sep->se_service, sep->se_proto);
1101                                                 goto serv_unknown;
1102                                         }
1103                                         port = sp->s_port;
1104                                 }
1105                                 if (port != sep->se_ctrladdr_in6.sin6_port) {
1106                                         sep->se_ctrladdr_in6.sin6_port = port;
1107                                         if (sep->se_fd != -1) {
1108                                                 FD_CLR(sep->se_fd, &allsock);
1109                                                 nsock--;
1110                                                 (void) close(sep->se_fd);
1111                                         }
1112                                         sep->se_fd = -1;
1113                                 }
1114                                 if (sep->se_fd == -1)
1115                                         setup(sep);
1116                         }
1117                         break;
1118 #endif /* FEATURE_IPV6 */
1119                 }
1120  serv_unknown:
1121                 if (cp->se_next != NULL) {
1122                         servtab_t *tmp = cp;
1123
1124                         cp = cp->se_next;
1125                         free(tmp);
1126                 } else {
1127                         free(cp);
1128                         cp = getconfigent();
1129                 }
1130         }
1131         endconfig();
1132         /*
1133          * Purge anything not looked at above.
1134          */
1135         Block_Using_Signals(omask);
1136         sepp = &servtab;
1137         while ((sep = *sepp)) {
1138                 if (sep->se_checked) {
1139                         sepp = &sep->se_next;
1140                         continue;
1141                 }
1142                 *sepp = sep->se_next;
1143                 if (sep->se_fd != -1) {
1144                         FD_CLR(sep->se_fd, &allsock);
1145                         nsock--;
1146                         (void) close(sep->se_fd);
1147                 }
1148 #if ENABLE_FEATURE_INETD_RPC
1149                 if (isrpcservice(sep))
1150                         unregister_rpc(sep);
1151 #endif
1152                 if (sep->se_family == AF_UNIX)
1153                         (void) unlink(sep->se_service);
1154                 freeconfig(sep);
1155                 free(sep);
1156         }
1157         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1158 }
1159
1160
1161 static void reapchild(int sig ATTRIBUTE_UNUSED)
1162 {
1163         pid_t pid;
1164         int save_errno = errno, status;
1165         servtab_t *sep;
1166
1167         for (;;) {
1168                 pid = wait3(&status, WNOHANG, NULL);
1169                 if (pid <= 0)
1170                         break;
1171                 for (sep = servtab; sep; sep = sep->se_next)
1172                         if (sep->se_wait == pid) {
1173                                 if (WIFEXITED(status) && WEXITSTATUS(status))
1174                                         bb_error_msg("%s: exit status 0x%x",
1175                                                         sep->se_server, WEXITSTATUS(status));
1176                                 else if (WIFSIGNALED(status))
1177                                         bb_error_msg("%s: exit signal 0x%x",
1178                                                         sep->se_server, WTERMSIG(status));
1179                                 sep->se_wait = 1;
1180                                 FD_SET(sep->se_fd, &allsock);
1181                                 nsock++;
1182                         }
1183         }
1184         errno = save_errno;
1185 }
1186
1187 static void retry(int sig ATTRIBUTE_UNUSED)
1188 {
1189         servtab_t *sep;
1190
1191         timingout = 0;
1192         for (sep = servtab; sep; sep = sep->se_next) {
1193                 if (sep->se_fd == -1) {
1194                         switch (sep->se_family) {
1195                         case AF_UNIX:
1196                         case AF_INET:
1197 #if ENABLE_FEATURE_IPV6
1198                         case AF_INET6:
1199 #endif
1200                                 setup(sep);
1201 #if ENABLE_FEATURE_INETD_RPC
1202                                 if (sep->se_fd != -1 && isrpcservice(sep))
1203                                         register_rpc(sep);
1204 #endif
1205                                 break;
1206                         }
1207                 }
1208         }
1209 }
1210
1211 static void goaway(int sig ATTRIBUTE_UNUSED)
1212 {
1213         servtab_t *sep;
1214
1215         /* XXX signal race walking sep list */
1216         for (sep = servtab; sep; sep = sep->se_next) {
1217                 if (sep->se_fd == -1)
1218                         continue;
1219
1220                 switch (sep->se_family) {
1221                 case AF_UNIX:
1222                         (void) unlink(sep->se_service);
1223                         break;
1224                 case AF_INET:
1225 #if ENABLE_FEATURE_IPV6
1226                 case AF_INET6:
1227 #endif
1228 #if ENABLE_FEATURE_INETD_RPC
1229                         if (sep->se_wait == 1 && isrpcservice(sep))
1230                                 unregister_rpc(sep);   /* XXX signal race */
1231 #endif
1232                         break;
1233                 }
1234                 (void) close(sep->se_fd);
1235         }
1236         remove_pidfile(_PATH_INETDPID);
1237         exit(0);
1238 }
1239
1240
1241 #ifdef INETD_SETPROCTITLE
1242
1243 static void
1244 inetd_setproctitle(char *a, int s)
1245 {
1246         socklen_t size;
1247         char *cp;
1248         struct sockaddr_in prt_sin;
1249         char buf[80];
1250
1251         cp = Argv[0];
1252         size = sizeof(prt_sin);
1253         (void) snprintf(buf, sizeof buf, "-%s", a);
1254         if (getpeername(s, (struct sockaddr *) &prt_sin, &size) == 0) {
1255                 char *sa = inet_ntoa(prt_sin.sin_addr);
1256
1257                 buf[sizeof(buf) - 1 - strlen(sa) - 3] = '\0';
1258                 strcat(buf, " [");
1259                 strcat(buf, sa);
1260                 strcat(buf, "]");
1261         }
1262         strncpy(cp, buf, LastArg - cp);
1263         cp += strlen(cp);
1264         while (cp < LastArg)
1265                 *cp++ = ' ';
1266 }
1267 #endif
1268
1269
1270 int inetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1271 int inetd_main(int argc, char **argv)
1272 {
1273         servtab_t *sep;
1274         struct passwd *pwd;
1275         struct group *grp = NULL;
1276         int tmpint;
1277         struct sigaction sa, sapipe;
1278         int opt;
1279         pid_t pid;
1280         char buf[50];
1281         char *stoomany;
1282         sigset_t omask, wait_mask;
1283 #ifdef INETD_SETPROCTITLE
1284         char **envp;
1285 #endif
1286
1287         INIT_G();
1288
1289 #ifdef INETD_SETPROCTITLE
1290         envp = environ;
1291         Argv = argv;
1292         if (envp == 0 || *envp == 0)
1293                 envp = argv;
1294         while (*envp)
1295                 envp++;
1296         LastArg = envp[-1] + strlen(envp[-1]);
1297 #endif
1298
1299         uid = getuid();
1300         if (uid != 0)
1301                 config_filename = NULL;
1302
1303         opt = getopt32(argv, "R:f", &stoomany);
1304         if (opt & 1)
1305                 toomany = xatoi_u(stoomany);
1306         argv += optind;
1307         argc -= optind;
1308         if (argc)
1309                 config_filename = argv[0];
1310         if (config_filename == NULL)
1311                 bb_error_msg_and_die("non-root must specify a config file");
1312
1313         if (!(opt & 2))
1314                 bb_daemonize_or_rexec(0, argv - optind);
1315         else
1316                 bb_sanitize_stdio();
1317         openlog(applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
1318         logmode = LOGMODE_SYSLOG;
1319
1320         if (uid == 0) {
1321                 /* If run by hand, ensure groups vector gets trashed */
1322                 gid_t gid = getgid();
1323                 setgroups(1, &gid);
1324         }
1325
1326         write_pidfile(_PATH_INETDPID);
1327
1328         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
1329                 bb_perror_msg("getrlimit");
1330         } else {
1331                 rlim_ofile_cur = rlim_ofile.rlim_cur;
1332                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
1333                         rlim_ofile_cur = OPEN_MAX;
1334         }
1335
1336         memset((char *) &sa, 0, sizeof(sa));
1337         sigemptyset(&sa.sa_mask);
1338         sigaddset(&sa.sa_mask, SIGALRM);
1339         sigaddset(&sa.sa_mask, SIGCHLD);
1340         sigaddset(&sa.sa_mask, SIGHUP);
1341         sa.sa_handler = retry;
1342         sigaction(SIGALRM, &sa, NULL);
1343         config(SIGHUP);
1344         sa.sa_handler = config;
1345         sigaction(SIGHUP, &sa, NULL);
1346         sa.sa_handler = reapchild;
1347         sigaction(SIGCHLD, &sa, NULL);
1348         sa.sa_handler = goaway;
1349         sigaction(SIGTERM, &sa, NULL);
1350         sa.sa_handler = goaway;
1351         sigaction(SIGINT, &sa, NULL);
1352         sa.sa_handler = SIG_IGN;
1353         sigaction(SIGPIPE, &sa, &sapipe);
1354         memset(&wait_mask, 0, sizeof(wait_mask));
1355         {
1356                 /* space for daemons to overwrite environment for ps */
1357 #define DUMMYSIZE       100
1358                 char dummy[DUMMYSIZE];
1359
1360                 (void) memset(dummy, 'x', DUMMYSIZE - 1);
1361                 dummy[DUMMYSIZE - 1] = '\0';
1362
1363                 (void) setenv("inetd_dummy", dummy, 1);
1364         }
1365
1366         for (;;) {
1367                 int n, ctrl = -1;
1368                 fd_set readable;
1369
1370                 if (nsock == 0) {
1371                         Block_Using_Signals(omask);
1372                         while (nsock == 0)
1373                                 sigsuspend(&wait_mask);
1374                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1375                 }
1376
1377                 readable = allsock;
1378                 n = select(maxsock + 1, &readable, NULL, NULL, NULL);
1379                 if (n <= 0) {
1380                         if (n < 0 && errno != EINTR) {
1381                                 bb_perror_msg("select");
1382                                 sleep(1);
1383                         }
1384                         continue;
1385                 }
1386
1387                 for (sep = servtab; n && sep; sep = sep->se_next) {
1388                         if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1389                                 continue;
1390
1391                         n--;
1392                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
1393                                 ctrl = accept(sep->se_fd, NULL, NULL);
1394                                 if (ctrl < 0) {
1395                                         if (errno == EINTR)
1396                                                 continue;
1397                                         bb_perror_msg("accept (for %s)", sep->se_service);
1398                                         continue;
1399                                 }
1400                                 if (sep->se_family == AF_INET && sep->se_socktype == SOCK_STREAM) {
1401                                         struct sockaddr_in peer;
1402                                         socklen_t plen = sizeof(peer);
1403
1404                                         if (getpeername(ctrl, (struct sockaddr *) &peer, &plen) < 0) {
1405                                                 bb_error_msg("cannot getpeername");
1406                                                 close(ctrl);
1407                                                 continue;
1408                                         }
1409                                         if (ntohs(peer.sin_port) == 20) {
1410                                                 /* XXX ftp bounce */
1411                                                 close(ctrl);
1412                                                 continue;
1413                                         }
1414                                 }
1415                         } else
1416                                 ctrl = sep->se_fd;
1417
1418                         Block_Using_Signals(omask);
1419                         pid = 0;
1420 #ifdef INETD_FEATURE_ENABLED
1421                         if (sep->se_bi == 0 || sep->se_bi->bi_fork)
1422 #endif
1423                         {
1424                                 if (sep->se_count++ == 0)
1425                                         (void) gettimeofday(&sep->se_time, NULL);
1426                                 else if (toomany > 0 && sep->se_count >= sep->se_max) {
1427                                         struct timeval now;
1428
1429                                         (void) gettimeofday(&now, NULL);
1430                                         if (now.tv_sec - sep->se_time.tv_sec > CNT_INTVL) {
1431                                                 sep->se_time = now;
1432                                                 sep->se_count = 1;
1433                                         } else {
1434                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1435                                                         close(ctrl);
1436                                                 if (sep->se_family == AF_INET &&
1437                                                           ntohs(sep->se_ctrladdr_in.sin_port) >= IPPORT_RESERVED) {
1438                                                         /*
1439                                                          * Cannot close it -- there are
1440                                                          * thieves on the system.
1441                                                          * Simply ignore the connection.
1442                                                          */
1443                                                         --sep->se_count;
1444                                                         continue;
1445                                                 }
1446                                                 bb_error_msg("%s/%s server failing (looping), service terminated",
1447                                                               sep->se_service, sep->se_proto);
1448                                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1449                                                         close(ctrl);
1450                                                 FD_CLR(sep->se_fd, &allsock);
1451                                                 (void) close(sep->se_fd);
1452                                                 sep->se_fd = -1;
1453                                                 sep->se_count = 0;
1454                                                 nsock--;
1455                                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1456                                                 if (!timingout) {
1457                                                         timingout = 1;
1458                                                         alarm(RETRYTIME);
1459                                                 }
1460                                                 continue;
1461                                         }
1462                                 }
1463                                 pid = fork();
1464                         }
1465                         if (pid < 0) {
1466                                 bb_perror_msg("fork");
1467                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1468                                         close(ctrl);
1469                                 sigprocmask(SIG_UNBLOCK, &omask, NULL);
1470                                 sleep(1);
1471                                 continue;
1472                         }
1473                         if (pid && sep->se_wait) {
1474                                 sep->se_wait = pid;
1475                                 FD_CLR(sep->se_fd, &allsock);
1476                                 nsock--;
1477                         }
1478                         sigprocmask(SIG_UNBLOCK, &omask, NULL);
1479                         if (pid == 0) {
1480 #ifdef INETD_FEATURE_ENABLED
1481                                 if (sep->se_bi) {
1482                                         (*sep->se_bi->bi_fn)(ctrl, sep);
1483                                 } else
1484 #endif
1485                                 {
1486                                         pwd = getpwnam(sep->se_user);
1487                                         if (pwd == NULL) {
1488                                                 bb_error_msg("getpwnam: %s: no such user", sep->se_user);
1489                                                 goto do_exit1;
1490                                         }
1491                                         if (setsid() < 0)
1492                                                 bb_perror_msg("%s: setsid", sep->se_service);
1493                                         if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1494                                                 bb_error_msg("getgrnam: %s: no such group", sep->se_group);
1495                                                 goto do_exit1;
1496                                         }
1497                                         if (uid != 0) {
1498                                                 /* a user running private inetd */
1499                                                 if (uid != pwd->pw_uid)
1500                                                         _exit(1);
1501                                         } else if (pwd->pw_uid) {
1502                                                 if (sep->se_group)
1503                                                         pwd->pw_gid = grp->gr_gid;
1504                                                 xsetgid((gid_t) pwd->pw_gid);
1505                                                 initgroups(pwd->pw_name, pwd->pw_gid);
1506                                                 xsetuid((uid_t) pwd->pw_uid);
1507                                         } else if (sep->se_group) {
1508                                                 xsetgid(grp->gr_gid);
1509                                                 setgroups(1, &grp->gr_gid);
1510                                         }
1511                                         dup2(ctrl, 0);
1512                                         if (ctrl) close(ctrl);
1513                                         dup2(0, 1);
1514                                         dup2(0, 2);
1515                                         if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1516                                                 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1517                                                         bb_perror_msg("setrlimit");
1518                                         closelog();
1519                                         for (tmpint = rlim_ofile_cur - 1; --tmpint > 2;)
1520                                                 (void) close(tmpint);
1521                                         sigaction(SIGPIPE, &sapipe, NULL);
1522                                         execv(sep->se_server, sep->se_argv);
1523                                         bb_perror_msg("execv %s", sep->se_server);
1524  do_exit1:
1525                                         if (sep->se_socktype != SOCK_STREAM)
1526                                                 recv(0, buf, sizeof(buf), 0);
1527                                         _exit(1);
1528                                 }
1529                         }
1530                         if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
1531                                 close(ctrl);
1532                 } /* for (sep = servtab...) */
1533         } /* for (;;) */
1534 }
1535
1536 /*
1537  * Internet services provided internally by inetd:
1538  */
1539 #define BUFSIZE 4096
1540
1541 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO || \
1542         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN || \
1543         ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1544 static int dg_badinput(struct sockaddr_in *dg_sin)
1545 {
1546         if (ntohs(dg_sin->sin_port) < IPPORT_RESERVED)
1547                 return 1;
1548         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST))
1549                 return 1;
1550         /* XXX compare against broadcast addresses in SIOCGIFCONF list? */
1551         return 0;
1552 }
1553 #endif
1554
1555 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1556 /* Echo service -- echo data back */
1557 /* ARGSUSED */
1558 static void
1559 echo_stream(int s, servtab_t *sep)
1560 {
1561         char buffer[BUFSIZE];
1562         int i;
1563
1564         inetd_setproctitle(sep->se_service, s);
1565         while (1) {
1566                 i = read(s, buffer, sizeof(buffer));
1567                 if (i <= 0) break;
1568                 /* FIXME: this isnt correct - safe_write()? */
1569                 if (write(s, buffer, i) <= 0) break;
1570         }
1571         exit(0);
1572 }
1573
1574 /* Echo service -- echo data back */
1575 /* ARGSUSED */
1576 static void
1577 echo_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1578 {
1579         char buffer[BUFSIZE];
1580         int i;
1581         socklen_t size;
1582         /* struct sockaddr_storage ss; */
1583         struct sockaddr sa;
1584
1585         size = sizeof(sa);
1586         i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size);
1587         if (i < 0)
1588                 return;
1589         if (dg_badinput((struct sockaddr_in *) &sa))
1590                 return;
1591         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1592 }
1593 #endif  /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1594
1595 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1596 /* Discard service -- ignore data */
1597 /* ARGSUSED */
1598 static void
1599 discard_stream(int s, servtab_t *sep)
1600 {
1601         char buffer[BUFSIZE];
1602
1603         inetd_setproctitle(sep->se_service, s);
1604         while (1) {
1605                 if (safe_read(s, buffer, sizeof(buffer)) <= 0)
1606                         exit(0);
1607         }
1608 }
1609
1610 /* Discard service -- ignore data */
1611 /* ARGSUSED */
1612 static void
1613 discard_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1614 {
1615         char buffer[BUFSIZE];
1616
1617         (void) read(s, buffer, sizeof(buffer));
1618 }
1619 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1620
1621
1622 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1623 #define LINESIZ 72
1624
1625 static void
1626 initring(void)
1627 {
1628         int i;
1629
1630         endring = ring;
1631         for (i = 0; i <= 128; ++i)
1632                 if (isprint(i))
1633                         *endring++ = i;
1634 }
1635
1636 /* Character generator */
1637 /* ARGSUSED */
1638 static void
1639 chargen_stream(int s, servtab_t *sep)
1640 {
1641         char *rs;
1642         int len;
1643         char text[LINESIZ + 2];
1644
1645         inetd_setproctitle(sep->se_service, s);
1646
1647         if (!endring) {
1648                 initring();
1649                 rs = ring;
1650         }
1651
1652         text[LINESIZ] = '\r';
1653         text[LINESIZ + 1] = '\n';
1654         rs = ring;
1655         for (;;) {
1656                 len = endring - rs;
1657                 if (len >= LINESIZ)
1658                         memmove(text, rs, LINESIZ);
1659                 else {
1660                         memmove(text, rs, len);
1661                         memmove(text + len, ring, LINESIZ - len);
1662                 }
1663                 if (++rs == endring)
1664                         rs = ring;
1665                 if (write(s, text, sizeof(text)) != sizeof(text))
1666                         break;
1667         }
1668         exit(0);
1669 }
1670
1671 /* Character generator */
1672 /* ARGSUSED */
1673 static void
1674 chargen_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1675 {
1676         /* struct sockaddr_storage ss; */
1677         struct sockaddr sa;
1678         int len;
1679         char text[LINESIZ + 2];
1680         socklen_t size;
1681
1682         if (!endring) {
1683                 initring();
1684                 ringpos = ring;
1685         }
1686
1687         size = sizeof(sa);
1688         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1689                 return;
1690         if (dg_badinput((struct sockaddr_in *) &sa))
1691                 return;
1692
1693         len = endring - ringpos;
1694         if (len >= LINESIZ)
1695                 memmove(text, ringpos, LINESIZ);
1696         else {
1697                 memmove(text, ringpos, len);
1698                 memmove(text + len, ring, LINESIZ - len);
1699         }
1700         if (++ringpos == endring)
1701                 ringpos = ring;
1702         text[LINESIZ] = '\r';
1703         text[LINESIZ + 1] = '\n';
1704         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1705 }
1706 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1707
1708
1709 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1710 /*
1711  * Return a machine readable date and time, in the form of the
1712  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1713  * returns the number of seconds since midnight, Jan 1, 1970,
1714  * we must add 2208988800 seconds to this figure to make up for
1715  * some seventy years Bell Labs was asleep.
1716  */
1717
1718 static unsigned machtime(void)
1719 {
1720         struct timeval tv;
1721
1722         if (gettimeofday(&tv, NULL) < 0) {
1723                 fprintf(stderr, "Unable to get time of day\n");
1724                 return 0L;
1725         }
1726         return htonl((unsigned) tv.tv_sec + 2208988800UL);
1727 }
1728
1729 /* ARGSUSED */
1730 static void
1731 machtime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1732 {
1733         unsigned result;
1734
1735         result = machtime();
1736         (void) write(s, (char *) &result, sizeof(result));
1737 }
1738
1739 /* ARGSUSED */
1740 static void
1741 machtime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1742 {
1743         unsigned result;
1744         /* struct sockaddr_storage ss; */
1745         struct sockaddr sa;
1746         struct sockaddr_in *dg_sin;
1747         socklen_t size;
1748
1749         size = sizeof(sa);
1750         if (recvfrom(s, (char *) &result, sizeof(result), 0, &sa, &size) < 0)
1751                 return;
1752         /* if (dg_badinput((struct sockaddr *)&ss)) */
1753         dg_sin = (struct sockaddr_in *) &sa;
1754         if (dg_sin->sin_addr.s_addr == htonl(INADDR_BROADCAST) ||
1755                         ntohs(dg_sin->sin_port) < IPPORT_RESERVED / 2)
1756                 return;
1757         result = machtime();
1758         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1759 }
1760 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1761
1762
1763 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1764 /* Return human-readable time of day */
1765 /* ARGSUSED */
1766 static void daytime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1767 {
1768         char buffer[32];
1769         time_t t;
1770
1771         t = time(NULL);
1772
1773 // fdprintf instead?
1774         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1775         (void) write(s, buffer, strlen(buffer));
1776 }
1777
1778 /* Return human-readable time of day */
1779 /* ARGSUSED */
1780 void
1781 daytime_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1782 {
1783         char buffer[256];
1784         time_t t;
1785         /* struct sockaddr_storage ss; */
1786         struct sockaddr sa;
1787         socklen_t size;
1788
1789         t = time(NULL);
1790
1791         size = sizeof(sa);
1792         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1793                 return;
1794         if (dg_badinput((struct sockaddr_in *) &sa))
1795                 return;
1796         (void) sprintf(buffer, "%.24s\r\n", ctime(&t));
1797         (void) sendto(s, buffer, strlen(buffer), 0, &sa, sizeof(sa));
1798 }
1799 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */