networking/inetd.c

   1 /*
   2  * Copyright (c) 1983,1991 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * David A. Holland.
   7  *
   8  * Busybox port by Vladimir Oleynik (C) 2001-2003 <dzo@simtreas.ru>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  *
  24  */
  25
  26 /*
  27  * Inetd - Internet super-server
  28  *
  29  * This program invokes all internet services as needed.
  30  * connection-oriented services are invoked each time a
  31  * connection is made, by creating a process.  This process
  32  * is passed the connection as file descriptor 0 and is
  33  * expected to do a getpeername to find out the source host
  34  * and port.
  35  *
  36  * Datagram oriented services are invoked when a datagram
  37  * arrives; a process is created and passed a pending message
  38  * on file descriptor 0.  Datagram servers may either connect
  39  * to their peer, freeing up the original socket for inetd
  40  * to receive further messages on, or ``take over the socket'',
  41  * processing all arriving datagrams and, eventually, timing
  42  * out.  The first type of server is said to be ``multi-threaded'';
  43  * the second type of server ``single-threaded''.
  44  *
  45  * Inetd uses a configuration file which is read at startup
  46  * and, possibly, at some later time in response to a hangup signal.
  47  * The configuration file is ``free format'' with fields given in the
  48  * order shown below.  Continuation lines for an entry must being with
  49  * a space or tab.  All fields must be present in each entry.
  50  *
  51  *      service name                    must be in /etc/services
  52  *      socket type                     stream/dgram/raw/rdm/seqpacket
  53  *      protocol                        must be in /etc/protocols
  54  *      wait/nowait[.max]               single-threaded/multi-threaded, max #
  55  *      user[.group]                    user/group to run daemon as
  56  *      server program                  full path name
  57  *      server program arguments        maximum of MAXARGS (20)
  58  *
  59  * RPC services unsuported
  60  *
  61  * Comment lines are indicated by a `#' in column 1.
  62  */
  63
  64 /*
  65  * Here's the scoop concerning the user.group feature:
  66  *
  67  * 1) No group listed.
  68  *
  69  *      a) for root:    NO setuid() or setgid() is done
  70  *
  71  *      b) nonroot:     setuid()
  72  *                      setgid(primary group as found in passwd)
  73  *                      initgroups(name, primary group)
  74  *
  75  * 2) set-group-option on.
  76  *
  77  *      a) for root:    NO setuid()
  78  *                      setgid(specified group)
  79  *                      setgroups(1, specified group)
  80  *
  81  *      b) nonroot:     setuid()
  82  *                      setgid(specified group)
  83  *                      initgroups(name, specified group)
  84  *
  85  * All supplementary groups are discarded at startup in case inetd was
  86  * run manually.
  87  */
  88
  89 #define __USE_BSD_SIGNAL
  90
  91 #include "busybox.h"
  92
  93 #include <sys/param.h>
  94 #include <sys/stat.h>
  95 #include <sys/ioctl.h>
  96 #include <sys/socket.h>
  97 #include <sys/un.h>
  98 #include <sys/file.h>
  99 #include <sys/wait.h>
 100 #include <sys/time.h>
 101 #include <sys/resource.h>
 102
 103 #ifndef __linux__
 104 #ifndef RLIMIT_NOFILE
 105 #define RLIMIT_NOFILE   RLIMIT_OFILE
 106 #endif
 107 #endif
 108
 109 #include <sys/param.h>
 110 #include <sys/stat.h>
 111 #include <sys/ioctl.h>
 112 #include <sys/socket.h>
 113 #include <sys/file.h>
 114 #include <sys/wait.h>
 115 #include <sys/time.h>
 116 #include <sys/resource.h>
 117
 118 #include <netinet/in.h>
 119 #include <netinet/ip.h>
 120 #include <arpa/inet.h>
 121
 122 #include <errno.h>
 123 #include <signal.h>
 124 #include <netdb.h>
 125 #include <syslog.h>
 126 #include <stdio.h>
 127 #include <stdlib.h>
 128 #include <string.h>
 129 #include <getopt.h>
 130 #include <unistd.h>
 131 #include <stdarg.h>
 132 #include <time.h>
 133
 134 #ifndef OPEN_MAX
 135 #define OPEN_MAX        64
 136 #endif
 137
 138 #define _PATH_INETDCONF "/etc/inetd.conf"
 139 #define _PATH_INETDPID  "/var/run/inetd.pid"
 140
 141 #define TOOMANY         40              /* don't start more than TOOMANY */
 142 #define CNT_INTVL       60              /* servers in CNT_INTVL sec. */
 143 #define RETRYTIME       (60*10) /* retry after bind or server fail */
 144 #define MAXARGV         20
 145
 146 #define se_ctrladdr             se_un.se_un_ctrladdr
 147 #define se_ctrladdr_in  se_un.se_un_ctrladdr_in
 148 #define se_ctrladdr_un  se_un.se_un_ctrladdr_un
 149
 150 /* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
 151 #define FD_MARGIN       (8)
 152
 153 /* Check unsupporting builtin */
 154 #if defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO || \
 155         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD || \
 156         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME || \
 157         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME || \
 158         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 159 # define INETD_FEATURE_ENABLED
 160 #endif
 161
 162 static struct  servtab {
 163         char    *se_service;            /* name of service */
 164         int     se_socktype;            /* type of socket to use */
 165         int     se_family;              /* address family */
 166         char    *se_proto;              /* protocol used */
 167         short   se_wait;                /* single threaded server */
 168         short   se_checked;             /* looked at during merge */
 169         char    *se_user;               /* user name to run as */
 170         char    *se_group;              /* group name to run as */
 171 #ifdef INETD_FEATURE_ENABLED
 172         const struct  biltin *se_bi;    /* if built-in, description */
 173 #endif
 174         char    *se_server;             /* server program */
 175         char    *se_argv[MAXARGV+1];    /* program arguments */
 176         int     se_fd;                  /* open descriptor */
 177         union {
 178                 struct  sockaddr se_un_ctrladdr;
 179                 struct  sockaddr_in se_un_ctrladdr_in;
 180                 struct  sockaddr_un se_un_ctrladdr_un;
 181         } se_un;                        /* bound address */
 182         int     se_ctrladdr_size;
 183         int     se_max;                 /* max # of instances of this service */
 184         int     se_count;               /* number started since se_time */
 185         struct  timeval se_time;        /* start of se_count */
 186         struct  servtab *se_next;
 187 } *servtab;
 188
 189 #ifdef INETD_FEATURE_ENABLED
 190 struct biltin {
 191         const char *bi_service;         /* internally provided service name */
 192         int bi_socktype;                /* type of socket supported */
 193         short bi_fork;          /* 1 if should fork before call */
 194         short bi_wait;          /* 1 if should wait for child */
 195         void (*bi_fn)(int, struct servtab *); /* fn which performs it */
 196 };
 197
 198     /* Echo received data */
 199 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
 200 static void echo_stream(int, struct servtab *);
 201 static void echo_dg(int, struct servtab *);
 202 #endif
 203     /* Internet /dev/null */
 204 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
 205 static void discard_stream(int, struct servtab *);
 206 static void discard_dg(int, struct servtab *);
 207 #endif
 208         /* Return 32 bit time since 1900 */
 209 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
 210 static void machtime_stream(int, struct servtab *);
 211 static void machtime_dg(int, struct servtab *);
 212 #endif
 213         /* Return human-readable time */
 214 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
 215 static void daytime_stream(int, struct servtab *);
 216 static void daytime_dg(int, struct servtab *);
 217 #endif
 218         /* Familiar character generator */
 219 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 220 static void chargen_stream(int, struct servtab *);
 221 static void chargen_dg(int, struct servtab *);
 222 #endif
 223
 224 static const struct biltin biltins[] = {
 225 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
 226         /* Echo received data */
 227         { "echo",               SOCK_STREAM,    1, 0,   echo_stream, },
 228         { "echo",               SOCK_DGRAM,     0, 0,   echo_dg, },
 229 #endif
 230 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
 231         /* Internet /dev/null */
 232         { "discard",    SOCK_STREAM,    1, 0,   discard_stream, },
 233         { "discard",    SOCK_DGRAM,     0, 0,   discard_dg, },
 234 #endif
 235 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
 236         /* Return 32 bit time since 1900 */
 237         { "time",               SOCK_STREAM,    0, 0,   machtime_stream, },
 238         { "time",               SOCK_DGRAM,     0, 0,   machtime_dg,     },
 239 #endif
 240 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
 241         /* Return human-readable time */
 242         { "daytime",    SOCK_STREAM,    0, 0,   daytime_stream, },
 243         { "daytime",    SOCK_DGRAM,     0, 0,   daytime_dg,     },
 244 #endif
 245 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 246         /* Familiar character generator */
 247         { "chargen",    SOCK_STREAM,    1, 0,   chargen_stream, },
 248         { "chargen",    SOCK_DGRAM,     0, 0,   chargen_dg,     },
 249 #endif
 250         { NULL, 0, 0, 0, NULL }
 251 };
 252 #endif  /* INETD_FEATURE_ENABLED */
 253
 254 #ifdef RLIMIT_NOFILE
 255 static struct rlimit   rlim_ofile;
 256 #endif
 257
 258 /* Length of socket listen queue. Should be per-service probably. */
 259 static int      global_queuelen = 128;
 260
 261 static FILE *fconfig;
 262 static sigset_t blockmask;
 263 static sigset_t emptymask;
 264 static fd_set   allsock;
 265 static int      nsock;
 266 static int      maxsock;
 267 static int      timingout;
 268 static int      rlim_ofile_cur = OPEN_MAX;
 269 static const char *CONFIG = _PATH_INETDCONF;
 270
 271 static void
 272 syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
 273         __attribute__ ((noreturn, format (printf, 2, 3)));
 274
 275 static void
 276 syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
 277 {
 278         char buf[50];
 279         va_list p;
 280
 281         va_start(p, msg);
 282         vsyslog(LOG_ERR, msg, p);
 283         if (se_socktype != SOCK_STREAM)
 284                 recv(0, buf, sizeof (buf), 0);
 285         _exit(1);
 286 }
 287
 288 static struct servtab *getconfigent(void)
 289 {
 290         static struct servtab serv;
 291         struct servtab *sep = &serv;
 292         int argc;
 293         char *cp = NULL;
 294         char *cp_ptr;
 295         char *cp_ptr_ptr = NULL;
 296
 297 more:
 298         free(cp);
 299         cp = bb_get_chomped_line_from_file(fconfig);
 300         if (feof(fconfig)) {
 301                 free(cp);
 302                 return (NULL);
 303         }
 304         if ((cp == NULL) || (*cp == '#')) {
 305                 goto more;
 306         }
 307         printf("line is %s\n", cp);
 308
 309         cp_ptr = strtok_r(cp, " \t", &cp_ptr_ptr);
 310         if (cp_ptr == NULL) {
 311                 printf("error\n");
 312                 /* Error */
 313                 goto more;
 314         }
 315         sep->se_service = bb_xstrdup(cp_ptr);
 316
 317         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 318         if (cp_ptr == NULL) {
 319                 printf("error\n");
 320                 /* Error */
 321                 goto more;
 322         }
 323         if (strcmp(cp_ptr, "stream") == 0)
 324                 sep->se_socktype = SOCK_STREAM;
 325         else if (strcmp(cp_ptr, "dgram") == 0)
 326                 sep->se_socktype = SOCK_DGRAM;
 327         else if (strcmp(cp_ptr, "rdm") == 0)
 328                 sep->se_socktype = SOCK_RDM;
 329         else if (strcmp(cp_ptr, "seqpacket") == 0)
 330                 sep->se_socktype = SOCK_SEQPACKET;
 331         else if (strcmp(cp_ptr, "raw") == 0)
 332                 sep->se_socktype = SOCK_RAW;
 333         else
 334                 sep->se_socktype = -1;
 335
 336         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 337         if (cp_ptr == NULL) {
 338                 printf("error\n");
 339                 /* error */
 340                 goto more;
 341         }
 342         if (strcmp(cp_ptr, "unix") == 0) {
 343                 sep->se_family = AF_UNIX;
 344         } else {
 345                 if (strncmp(cp_ptr, "rpc/", 4) == 0) {
 346                         syslog(LOG_ERR, "%s: rpc services not suported",
 347                             sep->se_service);
 348                         goto more;
 349                 }
 350                 sep->se_family = AF_INET;
 351         }
 352         sep->se_proto = bb_xstrdup(cp_ptr);
 353
 354         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 355         if (cp_ptr == NULL) {
 356                 printf("error\n");
 357                 /* error */
 358                 goto more;
 359         }
 360         {
 361                 char *s = strchr(cp_ptr, '.');
 362                 if (s) {
 363                         *s++ = '\0';
 364                         sep->se_max = atoi(s);
 365                 } else
 366                         sep->se_max = TOOMANY;
 367         }
 368         sep->se_wait = strcmp(cp_ptr, "wait") == 0;
 369
 370         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 371         if (cp_ptr == NULL) {
 372                 printf("error\n");
 373                 /* error */
 374                 goto more;
 375         }
 376         {
 377                 char *cp_ptr2 = strchr(cp_ptr, '.');
 378                 if (cp_ptr2) {
 379                         *cp_ptr2++ = '\0';
 380                         sep->se_group = bb_xstrdup(cp_ptr2);
 381                 }
 382         }
 383         sep->se_user = bb_xstrdup(cp_ptr);
 384
 385         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 386         if (cp_ptr == NULL) {
 387                 printf("error\n");
 388                 /* error */
 389                 goto more;
 390         }
 391         if (strcmp(cp_ptr, "internal") == 0) {
 392 #ifdef INETD_FEATURE_ENABLED
 393                 const struct biltin *bi;
 394
 395                 for (bi = biltins; bi->bi_service; bi++) {
 396                         if ((bi->bi_socktype == sep->se_socktype) &&
 397                             (strcmp(bi->bi_service, sep->se_service) == 0)) {
 398                                 break;
 399                         }
 400                 }
 401                 if (bi->bi_service == 0) {
 402                         syslog(LOG_ERR, "internal service %s unknown", sep->se_service);
 403                         goto more;
 404                 }
 405                 sep->se_bi = bi;
 406                 sep->se_wait = bi->bi_wait;
 407 #else
 408                 syslog(LOG_ERR, "internal service %s unknown", cp_ptr);
 409                 goto more;
 410 #endif
 411         }
 412 #ifdef INETD_FEATURE_ENABLED
 413         else {
 414                 sep->se_bi = NULL;
 415         }
 416 #endif
 417         sep->se_server = bb_xstrdup(cp_ptr);
 418
 419         argc = 0;
 420         while ((cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr)) != NULL) {
 421                 if (argc < MAXARGV) {
 422                         sep->se_argv[argc++] = cp_ptr;
 423                 }
 424         }
 425         while (argc <= MAXARGV) {
 426                 sep->se_argv[argc++] = NULL;
 427         }
 428
 429         //free(cp);     // BUG: cp is the argv[] container; we must not free it here!
 430         return (sep);
 431 }
 432
 433 static void freeconfig(struct servtab *cp)
 434 {
 435         int i;
 436
 437         free(cp->se_service);
 438         free(cp->se_proto);
 439         free(cp->se_user);
 440         /* Note: se_group is part of the newstr'ed se_user */
 441         free(cp->se_server);
 442         for (i = 0; i < MAXARGV; i++)
 443                 free(cp->se_argv[i]);
 444 }
 445
 446 #ifdef INETD_FEATURE_ENABLED
 447 static char **Argv;
 448 static char *LastArg;
 449
 450 static void setproctitle(char *a, int s)
 451 {
 452         size_t size;
 453         char *cp;
 454         struct sockaddr_in sn;
 455         char buf[80];
 456
 457         cp = Argv[0];
 458         size = sizeof(sn);
 459         if (getpeername(s, (struct sockaddr *)&sn, &size) == 0)
 460                 (void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sn.sin_addr));
 461         else
 462                 (void) sprintf(buf, "-%s", a);
 463         strncpy(cp, buf, LastArg - cp);
 464         cp += strlen(cp);
 465         while (cp < LastArg)
 466                 *cp++ = ' ';
 467 }
 468 #endif  /* INETD_FEATURE_ENABLED */
 469
 470
 471 static void setup(struct servtab *sep)
 472 {
 473         int on = 1;
 474
 475         if ((sep->se_fd = socket(sep->se_family, sep->se_socktype, 0)) < 0) {
 476                 syslog(LOG_ERR, "%s/%s: socket: %m",
 477                     sep->se_service, sep->se_proto);
 478                 return;
 479         }
 480         if (setsockopt(sep->se_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&on,
 481                             sizeof(on)) < 0)
 482                 syslog(LOG_ERR, "setsockopt (SO_REUSEADDR): %m");
 483         if (bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size) < 0) {
 484                 syslog(LOG_ERR, "%s/%s: bind: %m",
 485                     sep->se_service, sep->se_proto);
 486                 (void) close(sep->se_fd);
 487                 sep->se_fd = -1;
 488                 if (!timingout) {
 489                         timingout = 1;
 490                         alarm(RETRYTIME);
 491                 }
 492                 return;
 493         }
 494         if (sep->se_socktype == SOCK_STREAM)
 495                 listen(sep->se_fd, global_queuelen);
 496
 497         FD_SET(sep->se_fd, &allsock);
 498         nsock++;
 499         if (sep->se_fd > maxsock) {
 500                 maxsock = sep->se_fd;
 501                 if (maxsock > rlim_ofile_cur - FD_MARGIN) {
 502 #ifdef RLIMIT_NOFILE
 503 # define FD_CHUNK        32
 504                         struct rlimit rl;
 505
 506                         if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
 507                                 syslog(LOG_ERR, "getrlimit: %m");
 508                                 return;
 509                         }
 510                         rl.rlim_cur = rl.rlim_max < (rl.rlim_cur + FD_CHUNK) ? rl.rlim_max : (rl.rlim_cur + FD_CHUNK);
 511                         if (rl.rlim_cur <= rlim_ofile_cur) {
 512                                 syslog(LOG_ERR,
 513 # if _FILE_OFFSET_BITS == 64
 514                                         "bump_nofile: cannot extend file limit, max = %lld",
 515 # else
 516                                         "bump_nofile: cannot extend file limit, max = %ld",
 517 # endif
 518                                         rl.rlim_cur);
 519                                 return;
 520                         }
 521
 522                         if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
 523                                 syslog(LOG_ERR, "setrlimit: %m");
 524                                 return;
 525                         }
 526
 527                         rlim_ofile_cur = rl.rlim_cur;
 528                         return;
 529 #else
 530                         syslog(LOG_ERR, "bump_nofile: cannot extend file limit");
 531                         return;
 532 #endif  /* RLIMIT_NOFILE */
 533                 }
 534         }
 535 }
 536
 537 static void config(int signum)
 538 {
 539         struct servtab *sep, *cp, **sepp;
 540         sigset_t oldmask;
 541         unsigned n;
 542
 543         (void)signum;
 544
 545         if (fconfig != NULL) {
 546                 fseek(fconfig, 0L, L_SET);
 547         } else {
 548                 fconfig = fopen(CONFIG, "r");
 549                 if (fconfig == NULL) {
 550                         syslog(LOG_ERR, "%s: %m", CONFIG);
 551                         return;
 552                 }
 553         }
 554
 555         for (sep = servtab; sep; sep = sep->se_next)
 556                 sep->se_checked = 0;
 557         while ((cp = getconfigent()) != NULL) {
 558                 for (sep = servtab; sep; sep = sep->se_next)
 559                         if (strcmp(sep->se_service, cp->se_service) == 0 &&
 560                             strcmp(sep->se_proto, cp->se_proto) == 0)
 561                                 break;
 562                 if (sep != 0) {
 563                         int i;
 564
 565 #define SWAP(type, a, b) {type c=(type)a; (type)a=(type)b; (type)b=(type)c;}
 566
 567                         sigprocmask(SIG_BLOCK, &emptymask, &oldmask);
 568                         /*
 569                          * sep->se_wait may be holding the pid of a daemon
 570                          * that we're waiting for.  If so, don't overwrite
 571                          * it unless the config file explicitly says don't
 572                          * wait.
 573                          */
 574                         if (
 575 #ifdef INETD_FEATURE_ENABLED
 576                             cp->se_bi == 0 &&
 577 #endif
 578                             (sep->se_wait == 1 || cp->se_wait == 0))
 579                                 sep->se_wait = cp->se_wait;
 580                         if (cp->se_max != sep->se_max)
 581                                 SWAP(int, cp->se_max, sep->se_max);
 582                         if (cp->se_user)
 583                                 SWAP(char *, sep->se_user, cp->se_user);
 584                         if (cp->se_group)
 585                                 SWAP(char *, sep->se_group, cp->se_group);
 586                         if (cp->se_server)
 587                                 SWAP(char *, sep->se_server, cp->se_server);
 588                         for (i = 0; i < MAXARGV; i++)
 589                                 SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
 590 #undef SWAP
 591                         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 592                         // This freeconfig() is probably a bug, since it will try and free()
 593                         // each of the argv[] values, which are really just pointers
 594                         // into the middle of a single line buffer for the config file.
 595                         //freeconfig(cp);       // BUG?
 596                 } else {
 597                         sep = (struct servtab *)xmalloc(sizeof (*sep));
 598                         *sep = *cp;
 599                         sep->se_fd = -1;
 600                         sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
 601                         sep->se_next = servtab;
 602                         servtab = sep;
 603                         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 604                 }
 605                 sep->se_checked = 1;
 606
 607                 switch (sep->se_family) {
 608                 case AF_UNIX:
 609                         if (sep->se_fd != -1)
 610                                 break;
 611                         (void)unlink(sep->se_service);
 612                         n = strlen(sep->se_service);
 613                         if (n > sizeof(sep->se_ctrladdr_un.sun_path) - 1)
 614                                 n = sizeof(sep->se_ctrladdr_un.sun_path) - 1;
 615                         strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n);
 616                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
 617                         sep->se_ctrladdr_size = n +
 618                                         sizeof sep->se_ctrladdr_un.sun_family;
 619                         setup(sep);
 620                         break;
 621                 case AF_INET:
 622                         sep->se_ctrladdr_in.sin_family = AF_INET;
 623                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
 624                         {
 625                                 u_short port = bb_lookup_port(sep->se_service, sep->se_proto, 0);
 626
 627                                 if (port == 0) {
 628                                         syslog(LOG_ERR,
 629                                             "%s/%s: unknown service",
 630                                             sep->se_service, sep->se_proto);
 631                                         continue;
 632                                 }
 633                                 if (port != sep->se_ctrladdr_in.sin_port) {
 634                                         sep->se_ctrladdr_in.sin_port = port;
 635                                         if (sep->se_fd != -1) {
 636                                                 FD_CLR(sep->se_fd, &allsock);
 637                                                 nsock--;
 638                                                 (void) close(sep->se_fd);
 639                                         }
 640                                         sep->se_fd = -1;
 641                                 }
 642                                 if (sep->se_fd == -1)
 643                                         setup(sep);
 644                         }
 645                 }
 646         }
 647         if (fconfig) {
 648                 (void) fclose(fconfig);
 649                 fconfig = NULL;
 650         }
 651         /*
 652          * Purge anything not looked at above.
 653          */
 654         sigprocmask(SIG_SETMASK, &blockmask, &oldmask);
 655         sepp = &servtab;
 656         while ((sep = *sepp) != NULL) {
 657                 if (sep->se_checked) {
 658                         sepp = &sep->se_next;
 659                         continue;
 660                 }
 661                 *sepp = sep->se_next;
 662                 if (sep->se_fd != -1) {
 663                         FD_CLR(sep->se_fd, &allsock);
 664                         nsock--;
 665                         (void) close(sep->se_fd);
 666                 }
 667                 if (sep->se_family == AF_UNIX)
 668                         (void)unlink(sep->se_service);
 669                 freeconfig(sep);
 670                 free((char *)sep);
 671         }
 672         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 673 }
 674
 675
 676
 677 static void reapchild(int signum)
 678 {
 679         int status;
 680         int pid;
 681         struct servtab *sep;
 682
 683         (void)signum;
 684         for (;;) {
 685                 pid = wait3(&status, WNOHANG, (struct rusage *)0);
 686                 if (pid <= 0)
 687                         break;
 688                 for (sep = servtab; sep; sep = sep->se_next)
 689                         if (sep->se_wait == pid) {
 690                                 if (WIFEXITED(status) && WEXITSTATUS(status))
 691                                         syslog(LOG_WARNING,
 692                                             "%s: exit status 0x%x",
 693                                             sep->se_server, WEXITSTATUS(status));
 694                                 else if (WIFSIGNALED(status))
 695                                         syslog(LOG_WARNING,
 696                                             "%s: exit signal 0x%x",
 697                                             sep->se_server, WTERMSIG(status));
 698                                 sep->se_wait = 1;
 699                                 FD_SET(sep->se_fd, &allsock);
 700                                 nsock++;
 701                         }
 702         }
 703 }
 704
 705 static void retry(int signum)
 706 {
 707         struct servtab *sep;
 708
 709         (void)signum;
 710         timingout = 0;
 711         for (sep = servtab; sep; sep = sep->se_next) {
 712                 if (sep->se_fd == -1) {
 713                         switch (sep->se_family) {
 714                         case AF_UNIX:
 715                         case AF_INET:
 716                                 setup(sep);
 717                                 break;
 718                         }
 719                 }
 720         }
 721 }
 722
 723 static void goaway(int signum)
 724 {
 725         struct servtab *sep;
 726
 727         (void)signum;
 728         for (sep = servtab; sep; sep = sep->se_next)
 729                 if (sep->se_fd != -1 && sep->se_family == AF_UNIX)
 730                         (void)unlink(sep->se_service);
 731         (void)unlink(_PATH_INETDPID);
 732         exit(0);
 733 }
 734
 735
 736
 737 extern int inetd_main(int argc, char *argv[])
 738 {
 739         struct servtab *sep;
 740         struct group *grp = NULL;
 741         struct sigaction sa;
 742         int pid;
 743         unsigned long opt;
 744         char *sq;
 745         gid_t gid;
 746
 747 #ifdef INETD_FEATURE_ENABLED
 748         extern char **environ;
 749 #endif
 750
 751         gid = getgid();
 752         setgroups(1, &gid);
 753
 754 #ifdef INETD_FEATURE_ENABLED
 755         Argv = argv;
 756         if (environ == 0 || *environ == 0)
 757                 environ = argv;
 758         while (*environ)
 759                 environ++;
 760         LastArg = environ[-1] + strlen(environ[-1]);
 761 #endif
 762
 763 #if defined(__uClinux__)
 764         opt = bb_getopt_ulflags(argc, argv, "q:f", &sq);
 765         if (!(opt & 2)) {
 766             daemon(0, 0);
 767             /* reexec for vfork() do continue parent */
 768             vfork_daemon_rexec(argc, argv, "-f");
 769         }
 770 #else
 771         opt = bb_getopt_ulflags(argc, argv, "q:", &sq);
 772         daemon(0, 0);
 773 #endif /* uClinux */
 774
 775         if(opt & 1) {
 776                         global_queuelen = atoi(optarg);
 777                         if (global_queuelen < 8) global_queuelen=8;
 778                 }
 779         argc -= optind;
 780         argv += optind;
 781
 782         if (argc > 0)
 783                 CONFIG = argv[0];
 784
 785         openlog(bb_applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
 786         {
 787                 FILE *fp;
 788
 789                 if ((fp = fopen(_PATH_INETDPID, "w")) != NULL) {
 790                         fprintf(fp, "%u\n", getpid());
 791                         (void)fclose(fp);
 792                 }
 793         }
 794
 795 #ifdef RLIMIT_NOFILE
 796         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
 797                 syslog(LOG_ERR, "getrlimit: %m");
 798         } else {
 799                 rlim_ofile_cur = rlim_ofile.rlim_cur;
 800                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
 801                         rlim_ofile_cur = OPEN_MAX;
 802         }
 803 #endif
 804
 805         config(0);
 806
 807         sigemptyset(&emptymask);
 808         sigemptyset(&blockmask);
 809         sigaddset(&blockmask, SIGCHLD);
 810         sigaddset(&blockmask, SIGHUP);
 811         sigaddset(&blockmask, SIGALRM);
 812
 813         memset(&sa, 0, sizeof(sa));
 814         sa.sa_mask = blockmask;
 815         sa.sa_handler = retry;
 816         sigaction(SIGALRM, &sa, NULL);
 817         sa.sa_handler = config;
 818         sigaction(SIGHUP, &sa, NULL);
 819         sa.sa_handler = reapchild;
 820         sigaction(SIGCHLD, &sa, NULL);
 821         sa.sa_handler = goaway;
 822         sigaction(SIGTERM, &sa, NULL);
 823         sa.sa_handler = goaway;
 824         sigaction(SIGINT, &sa,  NULL);
 825         sa.sa_handler = SIG_IGN;
 826         sigaction(SIGPIPE, &sa, NULL);
 827
 828         {
 829                 /* space for daemons to overwrite environment for ps */
 830 #define DUMMYSIZE       100
 831                 char dummy[DUMMYSIZE];
 832
 833                 (void)memset(dummy, 'x', DUMMYSIZE - 1);
 834                 dummy[DUMMYSIZE - 1] = '\0';
 835
 836                 (void)setenv("inetd_dummy", dummy, 1);
 837         }
 838
 839         for (;;) {
 840             int n, ctrl;
 841             fd_set readable;
 842
 843             if (nsock == 0) {
 844                 sigprocmask(SIG_BLOCK, &blockmask, NULL);
 845                 while (nsock == 0)
 846                     sigsuspend(&emptymask);
 847                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 848             }
 849             readable = allsock;
 850             if ((n = select(maxsock + 1, &readable, (fd_set *)0,
 851                 (fd_set *)0, (struct timeval *)0)) <= 0) {
 852                     if (n < 0 && errno != EINTR)
 853                         syslog(LOG_WARNING, "select: %m");
 854                     sleep(1);
 855                     continue;
 856             }
 857             for (sep = servtab; n && sep; sep = sep->se_next)
 858             if (sep->se_fd != -1 && FD_ISSET(sep->se_fd, &readable)) {
 859                 n--;
 860                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
 861                         /* Fixed AGC */
 862                         fcntl(sep->se_fd, F_SETFL, O_NDELAY);
 863                         /* --------- */
 864                         ctrl = accept(sep->se_fd, NULL, NULL);
 865                         fcntl(sep->se_fd, F_SETFL, 0);
 866                         if (ctrl < 0) {
 867                                 if (errno == EINTR || errno == EWOULDBLOCK)
 868                                         continue;
 869                                 syslog(LOG_WARNING, "accept (for %s): %m",
 870                                         sep->se_service);
 871                                 continue;
 872                         }
 873                 } else
 874                         ctrl = sep->se_fd;
 875                 sigprocmask(SIG_BLOCK, &blockmask, NULL);
 876                 pid = 0;
 877 #ifdef INETD_FEATURE_ENABLED
 878                 if (sep->se_bi == 0 || sep->se_bi->bi_fork)
 879 #endif
 880                 {
 881                         if (sep->se_count++ == 0)
 882                             (void)gettimeofday(&sep->se_time, (struct timezone *)0);
 883                         else if (sep->se_count >= sep->se_max) {
 884                                 struct timeval now;
 885
 886                                 (void)gettimeofday(&now, (struct timezone *)0);
 887                                 if (now.tv_sec - sep->se_time.tv_sec >
 888                                     CNT_INTVL) {
 889                                         sep->se_time = now;
 890                                         sep->se_count = 1;
 891                                 } else {
 892                                         syslog(LOG_ERR,
 893                         "%s/%s server failing (looping), service terminated",
 894                                             sep->se_service, sep->se_proto);
 895                                         FD_CLR(sep->se_fd, &allsock);
 896                                         (void) close(sep->se_fd);
 897                                         sep->se_fd = -1;
 898                                         sep->se_count = 0;
 899                                         nsock--;
 900                                         sigprocmask(SIG_SETMASK, &emptymask,
 901                                                     NULL);
 902                                         if (!timingout) {
 903                                                 timingout = 1;
 904                                                 alarm(RETRYTIME);
 905                                         }
 906                                         continue;
 907                                 }
 908                         }
 909                         pid = fork();
 910                         if (pid < 0) {
 911                                 syslog(LOG_ERR, "fork: %m");
 912                                 if (sep->se_socktype == SOCK_STREAM)
 913                                         close(ctrl);
 914                                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 915                                 sleep(1);
 916                                 continue;
 917                         }
 918                         if (pid && sep->se_wait) {
 919                                 sep->se_wait = pid;
 920                                 FD_CLR(sep->se_fd, &allsock);
 921                                 nsock--;
 922                         }
 923                 }
 924                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 925                 if (pid == 0) {
 926 #ifdef INETD_FEATURE_ENABLED
 927                         if (sep->se_bi)
 928                                 (*sep->se_bi->bi_fn)(ctrl, sep);
 929                         else
 930 #endif
 931                         {
 932                                 struct passwd *pwd = getpwnam(sep->se_user);
 933                                 if (pwd == NULL) {
 934                                         syslog_err_and_discard_dg(
 935                                                 sep->se_socktype,
 936                                                 "getpwnam: %s: No such user",
 937                                                 sep->se_user);
 938                                 }
 939                                 if (sep->se_group &&
 940                                     (grp = getgrnam(sep->se_group)) == NULL) {
 941                                         syslog_err_and_discard_dg(
 942                                                 sep->se_socktype,
 943                                                 "getgrnam: %s: No such group",
 944                                                 sep->se_group);
 945                                 }
 946                                 /*
 947                                  * Ok. There are four cases here:
 948                                  *   1. nonroot user, no group specified
 949                                  *   2. nonroot user, some group specified
 950                                  *   3. root user, no group specified
 951                                  *   4. root user, some group specified
 952                                  * In cases 2 and 4 we setgid to the specified
 953                                  * group. In cases 1 and 2 we run initgroups
 954                                  * to run with the groups of the given user.
 955                                  * In case 4 we do setgroups to run with the
 956                                  * given group. In case 3 we do nothing.
 957                                  */
 958                                 if (pwd->pw_uid) {
 959                                         if (sep->se_group)
 960                                                 pwd->pw_gid = grp->gr_gid;
 961                                         setgid((gid_t)pwd->pw_gid);
 962                                         initgroups(pwd->pw_name, pwd->pw_gid);
 963                                         setuid((uid_t)pwd->pw_uid);
 964                                 } else if (sep->se_group) {
 965                                         setgid((gid_t)grp->gr_gid);
 966                                         setgroups(1, &grp->gr_gid);
 967                                 }
 968                                 dup2(ctrl, 0);
 969                                 close(ctrl);
 970                                 dup2(0, 1);
 971                                 dup2(0, 2);
 972 #ifdef RLIMIT_NOFILE
 973                                 if (rlim_ofile.rlim_cur != rlim_ofile_cur) {
 974                                         if (setrlimit(RLIMIT_NOFILE,
 975                                                         &rlim_ofile) < 0)
 976                                                 syslog(LOG_ERR,"setrlimit: %m");
 977                                 }
 978 #endif
 979                                 for (ctrl = rlim_ofile_cur-1; --ctrl > 2; )
 980                                         (void)close(ctrl);
 981
 982                                 memset(&sa, 0, sizeof(sa));
 983                                 sa.sa_handler = SIG_DFL;
 984                                 sigaction(SIGPIPE, &sa, NULL);
 985
 986                                 execv(sep->se_server, sep->se_argv);
 987                                 syslog_err_and_discard_dg(sep->se_socktype,
 988                                         "execv %s: %m", sep->se_server);
 989                         }
 990                 }
 991                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
 992                         close(ctrl);
 993             }
 994         }
 995 }
 996
 997
 998 /*
 999  * Internet services provided internally by inetd:
1000  */
1001 #define BUFSIZE 4096
1002
1003 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
1004 /* Echo service -- echo data back */
1005 static void echo_stream(int s, struct servtab *sep)
1006 {
1007         char buffer[BUFSIZE];
1008         int i;
1009
1010         setproctitle(sep->se_service, s);
1011         while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
1012             write(s, buffer, i) > 0)
1013                 ;
1014         exit(0);
1015 }
1016
1017 /* Echo service -- echo data back */
1018 static void echo_dg(int s, struct servtab *sep)
1019 {
1020         char buffer[BUFSIZE];
1021         int i;
1022         size_t size;
1023         struct sockaddr sa;
1024
1025         (void)sep;
1026
1027         size = sizeof(sa);
1028         if ((i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size)) < 0)
1029                 return;
1030         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1031 }
1032 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO */
1033
1034
1035 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
1036 /* Discard service -- ignore data */
1037 static void discard_stream(int s, struct servtab *sep)
1038 {
1039         char buffer[BUFSIZE];
1040
1041         setproctitle(sep->se_service, s);
1042         while ((errno = 0, read(s, buffer, sizeof(buffer)) > 0) ||
1043                         errno == EINTR)
1044                 ;
1045         exit(0);
1046 }
1047
1048 /* Discard service -- ignore data */
1049 static void discard_dg(int s, struct servtab *sep)
1050 {
1051         char buffer[BUFSIZE];
1052         (void)sep;
1053         read(s, buffer, sizeof(buffer));
1054 }
1055 #endif  /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD */
1056
1057
1058 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
1059 #include <ctype.h>
1060 #define LINESIZ 72
1061 static char ring[128];
1062 static char *endring;
1063
1064 static void initring(void)
1065 {
1066         int i;
1067
1068         endring = ring;
1069
1070         for (i = 0; i <= 128; ++i)
1071                 if (isprint(i))
1072                         *endring++ = i;
1073 }
1074
1075 /* Character generator */
1076 static void chargen_stream(int s, struct servtab *sep)
1077 {
1078         char *rs;
1079         int len;
1080         char text[LINESIZ+2];
1081
1082         setproctitle(sep->se_service, s);
1083
1084         if (!endring) {
1085                 initring();
1086                 rs = ring;
1087         }
1088
1089         text[LINESIZ] = '\r';
1090         text[LINESIZ + 1] = '\n';
1091         for (rs = ring;;) {
1092                 if ((len = endring - rs) >= LINESIZ)
1093                         memcpy(rs, text, LINESIZ);
1094                 else {
1095                         memcpy(rs, text, len);
1096                         memcpy(ring, text + len, LINESIZ - len);
1097                 }
1098                 if (++rs == endring)
1099                         rs = ring;
1100                 if (write(s, text, sizeof(text)) != sizeof(text))
1101                         break;
1102         }
1103         exit(0);
1104 }
1105
1106 /* Character generator */
1107 static void chargen_dg(int s, struct servtab *sep)
1108 {
1109         struct sockaddr sa;
1110         static char *rs;
1111         size_t len, size;
1112         char text[LINESIZ+2];
1113
1114         (void)sep;
1115
1116         if (endring == 0) {
1117                 initring();
1118                 rs = ring;
1119         }
1120
1121         size = sizeof(sa);
1122         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1123                 return;
1124
1125         if ((len = endring - rs) >= LINESIZ)
1126                 memcpy(rs, text, LINESIZ);
1127         else {
1128                 memcpy(rs, text, len);
1129                 memcpy(ring, text + len, LINESIZ - len);
1130         }
1131         if (++rs == endring)
1132                 rs = ring;
1133         text[LINESIZ] = '\r';
1134         text[LINESIZ + 1] = '\n';
1135         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1136 }
1137 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN */
1138
1139
1140 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
1141 /*
1142  * Return a machine readable date and time, in the form of the
1143  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1144  * returns the number of seconds since midnight, Jan 1, 1970,
1145  * we must add 2208988800 seconds to this figure to make up for
1146  * some seventy years Bell Labs was asleep.
1147  */
1148
1149 static long machtime(void)
1150 {
1151         struct timeval tv;
1152
1153         if (gettimeofday(&tv, (struct timezone *)0) < 0) {
1154                 fprintf(stderr, "Unable to get time of day\n");
1155                 return (0L);
1156         }
1157         return (htonl((long)tv.tv_sec + 2208988800UL));
1158 }
1159
1160 static void machtime_stream(int s, struct servtab *sep)
1161 {
1162         long result;
1163         (void)sep;
1164
1165         result = machtime();
1166         write(s, (char *) &result, sizeof(result));
1167 }
1168
1169 static void machtime_dg(int s, struct servtab *sep)
1170 {
1171         long result;
1172         struct sockaddr sa;
1173         size_t size;
1174         (void)sep;
1175
1176         size = sizeof(sa);
1177         if (recvfrom(s, (char *)&result, sizeof(result), 0, &sa, &size) < 0)
1178                 return;
1179         result = machtime();
1180         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1181 }
1182 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME */
1183
1184
1185 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
1186 /* Return human-readable time of day */
1187 static int human_readable_time_sprintf(char *buffer)
1188 {
1189         time_t clocc = time(NULL);
1190
1191         return sprintf(buffer, "%.24s\r\n", ctime(&clocc));
1192 }
1193
1194 static void daytime_stream(int s, struct servtab *sep)
1195 {
1196         char buffer[256];
1197         size_t st = human_readable_time_sprintf(buffer);
1198
1199         (void)sep;
1200
1201         write(s, buffer, st);
1202 }
1203
1204 /* Return human-readable time of day */
1205 static void daytime_dg(int s, struct servtab *sep)
1206 {
1207         char buffer[256];
1208         struct sockaddr sa;
1209         size_t size;
1210
1211         (void)sep;
1212
1213         size = sizeof(sa);
1214         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1215                 return;
1216         size = human_readable_time_sprintf(buffer);
1217         sendto(s, buffer, size, 0, &sa, sizeof(sa));
1218 }
1219 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME */