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);
 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                         freeconfig(cp);
 593                 } else {
 594                         sep = (struct servtab *)xmalloc(sizeof (*sep));
 595                         *sep = *cp;
 596                         sep->se_fd = -1;
 597                         sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
 598                         sep->se_next = servtab;
 599                         servtab = sep;
 600                         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 601                 }
 602                 sep->se_checked = 1;
 603
 604                 switch (sep->se_family) {
 605                 case AF_UNIX:
 606                         if (sep->se_fd != -1)
 607                                 break;
 608                         (void)unlink(sep->se_service);
 609                         n = strlen(sep->se_service);
 610                         if (n > sizeof(sep->se_ctrladdr_un.sun_path) - 1)
 611                                 n = sizeof(sep->se_ctrladdr_un.sun_path) - 1;
 612                         strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n);
 613                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
 614                         sep->se_ctrladdr_size = n +
 615                                         sizeof sep->se_ctrladdr_un.sun_family;
 616                         setup(sep);
 617                         break;
 618                 case AF_INET:
 619                         sep->se_ctrladdr_in.sin_family = AF_INET;
 620                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
 621                         {
 622                                 u_short port = bb_lookup_port(sep->se_service, sep->se_proto, 0);
 623
 624                                 if (port == 0) {
 625                                         syslog(LOG_ERR,
 626                                             "%s/%s: unknown service",
 627                                             sep->se_service, sep->se_proto);
 628                                         continue;
 629                                 }
 630                                 if (port != sep->se_ctrladdr_in.sin_port) {
 631                                         sep->se_ctrladdr_in.sin_port = port;
 632                                         if (sep->se_fd != -1) {
 633                                                 FD_CLR(sep->se_fd, &allsock);
 634                                                 nsock--;
 635                                                 (void) close(sep->se_fd);
 636                                         }
 637                                         sep->se_fd = -1;
 638                                 }
 639                                 if (sep->se_fd == -1)
 640                                         setup(sep);
 641                         }
 642                 }
 643         }
 644         if (fconfig) {
 645                 (void) fclose(fconfig);
 646                 fconfig = NULL;
 647         }
 648         /*
 649          * Purge anything not looked at above.
 650          */
 651         sigprocmask(SIG_SETMASK, &blockmask, &oldmask);
 652         sepp = &servtab;
 653         while ((sep = *sepp) != NULL) {
 654                 if (sep->se_checked) {
 655                         sepp = &sep->se_next;
 656                         continue;
 657                 }
 658                 *sepp = sep->se_next;
 659                 if (sep->se_fd != -1) {
 660                         FD_CLR(sep->se_fd, &allsock);
 661                         nsock--;
 662                         (void) close(sep->se_fd);
 663                 }
 664                 if (sep->se_family == AF_UNIX)
 665                         (void)unlink(sep->se_service);
 666                 freeconfig(sep);
 667                 free((char *)sep);
 668         }
 669         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 670 }
 671
 672
 673
 674 static void reapchild(int signum)
 675 {
 676         int status;
 677         int pid;
 678         struct servtab *sep;
 679
 680         (void)signum;
 681         for (;;) {
 682                 pid = wait3(&status, WNOHANG, (struct rusage *)0);
 683                 if (pid <= 0)
 684                         break;
 685                 for (sep = servtab; sep; sep = sep->se_next)
 686                         if (sep->se_wait == pid) {
 687                                 if (WIFEXITED(status) && WEXITSTATUS(status))
 688                                         syslog(LOG_WARNING,
 689                                             "%s: exit status 0x%x",
 690                                             sep->se_server, WEXITSTATUS(status));
 691                                 else if (WIFSIGNALED(status))
 692                                         syslog(LOG_WARNING,
 693                                             "%s: exit signal 0x%x",
 694                                             sep->se_server, WTERMSIG(status));
 695                                 sep->se_wait = 1;
 696                                 FD_SET(sep->se_fd, &allsock);
 697                                 nsock++;
 698                         }
 699         }
 700 }
 701
 702 static void retry(int signum)
 703 {
 704         struct servtab *sep;
 705
 706         (void)signum;
 707         timingout = 0;
 708         for (sep = servtab; sep; sep = sep->se_next) {
 709                 if (sep->se_fd == -1) {
 710                         switch (sep->se_family) {
 711                         case AF_UNIX:
 712                         case AF_INET:
 713                                 setup(sep);
 714                                 break;
 715                         }
 716                 }
 717         }
 718 }
 719
 720 static void goaway(int signum)
 721 {
 722         struct servtab *sep;
 723
 724         (void)signum;
 725         for (sep = servtab; sep; sep = sep->se_next)
 726                 if (sep->se_fd != -1 && sep->se_family == AF_UNIX)
 727                         (void)unlink(sep->se_service);
 728         (void)unlink(_PATH_INETDPID);
 729         exit(0);
 730 }
 731
 732
 733
 734 extern int inetd_main(int argc, char *argv[])
 735 {
 736         struct servtab *sep;
 737         struct group *grp = NULL;
 738         struct sigaction sa;
 739         int pid;
 740         unsigned long opt;
 741         char *sq;
 742         gid_t gid;
 743
 744 #ifdef INETD_FEATURE_ENABLED
 745         extern char **environ;
 746 #endif
 747
 748         gid = getgid();
 749         setgroups(1, &gid);
 750
 751 #ifdef INETD_FEATURE_ENABLED
 752         Argv = argv;
 753         if (environ == 0 || *environ == 0)
 754                 environ = argv;
 755         while (*environ)
 756                 environ++;
 757         LastArg = environ[-1] + strlen(environ[-1]);
 758 #endif
 759
 760 #if defined(__uClinux__)
 761         opt = bb_getopt_ulflags(argc, argv, "q:f", &sq);
 762         if (!(opt & 2)) {
 763             daemon(0, 0);
 764             /* reexec for vfork() do continue parent */
 765             vfork_daemon_rexec(argc, argv, "-f");
 766         }
 767 #else
 768         opt = bb_getopt_ulflags(argc, argv, "q:", &sq);
 769         daemon(0, 0);
 770 #endif /* uClinux */
 771
 772         if(opt & 1) {
 773                         global_queuelen = atoi(optarg);
 774                         if (global_queuelen < 8) global_queuelen=8;
 775                 }
 776         argc -= optind;
 777         argv += optind;
 778
 779         if (argc > 0)
 780                 CONFIG = argv[0];
 781
 782         openlog(bb_applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
 783         {
 784                 FILE *fp;
 785
 786                 if ((fp = fopen(_PATH_INETDPID, "w")) != NULL) {
 787                         fprintf(fp, "%u\n", getpid());
 788                         (void)fclose(fp);
 789                 }
 790         }
 791
 792 #ifdef RLIMIT_NOFILE
 793         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
 794                 syslog(LOG_ERR, "getrlimit: %m");
 795         } else {
 796                 rlim_ofile_cur = rlim_ofile.rlim_cur;
 797                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
 798                         rlim_ofile_cur = OPEN_MAX;
 799         }
 800 #endif
 801
 802         config(0);
 803
 804         sigemptyset(&emptymask);
 805         sigemptyset(&blockmask);
 806         sigaddset(&blockmask, SIGCHLD);
 807         sigaddset(&blockmask, SIGHUP);
 808         sigaddset(&blockmask, SIGALRM);
 809
 810         memset(&sa, 0, sizeof(sa));
 811         sa.sa_mask = blockmask;
 812         sa.sa_handler = retry;
 813         sigaction(SIGALRM, &sa, NULL);
 814         sa.sa_handler = config;
 815         sigaction(SIGHUP, &sa, NULL);
 816         sa.sa_handler = reapchild;
 817         sigaction(SIGCHLD, &sa, NULL);
 818         sa.sa_handler = goaway;
 819         sigaction(SIGTERM, &sa, NULL);
 820         sa.sa_handler = goaway;
 821         sigaction(SIGINT, &sa,  NULL);
 822         sa.sa_handler = SIG_IGN;
 823         sigaction(SIGPIPE, &sa, NULL);
 824
 825         {
 826                 /* space for daemons to overwrite environment for ps */
 827 #define DUMMYSIZE       100
 828                 char dummy[DUMMYSIZE];
 829
 830                 (void)memset(dummy, 'x', DUMMYSIZE - 1);
 831                 dummy[DUMMYSIZE - 1] = '\0';
 832
 833                 (void)setenv("inetd_dummy", dummy, 1);
 834         }
 835
 836         for (;;) {
 837             int n, ctrl;
 838             fd_set readable;
 839
 840             if (nsock == 0) {
 841                 sigprocmask(SIG_BLOCK, &blockmask, NULL);
 842                 while (nsock == 0)
 843                     sigsuspend(&emptymask);
 844                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 845             }
 846             readable = allsock;
 847             if ((n = select(maxsock + 1, &readable, (fd_set *)0,
 848                 (fd_set *)0, (struct timeval *)0)) <= 0) {
 849                     if (n < 0 && errno != EINTR)
 850                         syslog(LOG_WARNING, "select: %m");
 851                     sleep(1);
 852                     continue;
 853             }
 854             for (sep = servtab; n && sep; sep = sep->se_next)
 855             if (sep->se_fd != -1 && FD_ISSET(sep->se_fd, &readable)) {
 856                 n--;
 857                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
 858                         /* Fixed AGC */
 859                         fcntl(sep->se_fd, F_SETFL, O_NDELAY);
 860                         /* --------- */
 861                         ctrl = accept(sep->se_fd, NULL, NULL);
 862                         fcntl(sep->se_fd, F_SETFL, 0);
 863                         if (ctrl < 0) {
 864                                 if (errno == EINTR || errno == EWOULDBLOCK)
 865                                         continue;
 866                                 syslog(LOG_WARNING, "accept (for %s): %m",
 867                                         sep->se_service);
 868                                 continue;
 869                         }
 870                 } else
 871                         ctrl = sep->se_fd;
 872                 sigprocmask(SIG_BLOCK, &blockmask, NULL);
 873                 pid = 0;
 874 #ifdef INETD_FEATURE_ENABLED
 875                 if (sep->se_bi == 0 || sep->se_bi->bi_fork)
 876 #endif
 877                 {
 878                         if (sep->se_count++ == 0)
 879                             (void)gettimeofday(&sep->se_time, (struct timezone *)0);
 880                         else if (sep->se_count >= sep->se_max) {
 881                                 struct timeval now;
 882
 883                                 (void)gettimeofday(&now, (struct timezone *)0);
 884                                 if (now.tv_sec - sep->se_time.tv_sec >
 885                                     CNT_INTVL) {
 886                                         sep->se_time = now;
 887                                         sep->se_count = 1;
 888                                 } else {
 889                                         syslog(LOG_ERR,
 890                         "%s/%s server failing (looping), service terminated",
 891                                             sep->se_service, sep->se_proto);
 892                                         FD_CLR(sep->se_fd, &allsock);
 893                                         (void) close(sep->se_fd);
 894                                         sep->se_fd = -1;
 895                                         sep->se_count = 0;
 896                                         nsock--;
 897                                         sigprocmask(SIG_SETMASK, &emptymask,
 898                                                     NULL);
 899                                         if (!timingout) {
 900                                                 timingout = 1;
 901                                                 alarm(RETRYTIME);
 902                                         }
 903                                         continue;
 904                                 }
 905                         }
 906                         pid = fork();
 907                         if (pid < 0) {
 908                                 syslog(LOG_ERR, "fork: %m");
 909                                 if (sep->se_socktype == SOCK_STREAM)
 910                                         close(ctrl);
 911                                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 912                                 sleep(1);
 913                                 continue;
 914                         }
 915                         if (pid && sep->se_wait) {
 916                                 sep->se_wait = pid;
 917                                 FD_CLR(sep->se_fd, &allsock);
 918                                 nsock--;
 919                         }
 920                 }
 921                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 922                 if (pid == 0) {
 923 #ifdef INETD_FEATURE_ENABLED
 924                         if (sep->se_bi)
 925                                 (*sep->se_bi->bi_fn)(ctrl, sep);
 926                         else
 927 #endif
 928                         {
 929                                 struct passwd *pwd = getpwnam(sep->se_user);
 930                                 if (pwd == NULL) {
 931                                         syslog_err_and_discard_dg(
 932                                                 sep->se_socktype,
 933                                                 "getpwnam: %s: No such user",
 934                                                 sep->se_user);
 935                                 }
 936                                 if (sep->se_group &&
 937                                     (grp = getgrnam(sep->se_group)) == NULL) {
 938                                         syslog_err_and_discard_dg(
 939                                                 sep->se_socktype,
 940                                                 "getgrnam: %s: No such group",
 941                                                 sep->se_group);
 942                                 }
 943                                 /*
 944                                  * Ok. There are four cases here:
 945                                  *   1. nonroot user, no group specified
 946                                  *   2. nonroot user, some group specified
 947                                  *   3. root user, no group specified
 948                                  *   4. root user, some group specified
 949                                  * In cases 2 and 4 we setgid to the specified
 950                                  * group. In cases 1 and 2 we run initgroups
 951                                  * to run with the groups of the given user.
 952                                  * In case 4 we do setgroups to run with the
 953                                  * given group. In case 3 we do nothing.
 954                                  */
 955                                 if (pwd->pw_uid) {
 956                                         if (sep->se_group)
 957                                                 pwd->pw_gid = grp->gr_gid;
 958                                         setgid((gid_t)pwd->pw_gid);
 959                                         initgroups(pwd->pw_name, pwd->pw_gid);
 960                                         setuid((uid_t)pwd->pw_uid);
 961                                 } else if (sep->se_group) {
 962                                         setgid((gid_t)grp->gr_gid);
 963                                         setgroups(1, &grp->gr_gid);
 964                                 }
 965                                 dup2(ctrl, 0);
 966                                 close(ctrl);
 967                                 dup2(0, 1);
 968                                 dup2(0, 2);
 969 #ifdef RLIMIT_NOFILE
 970                                 if (rlim_ofile.rlim_cur != rlim_ofile_cur) {
 971                                         if (setrlimit(RLIMIT_NOFILE,
 972                                                         &rlim_ofile) < 0)
 973                                                 syslog(LOG_ERR,"setrlimit: %m");
 974                                 }
 975 #endif
 976                                 for (ctrl = rlim_ofile_cur-1; --ctrl > 2; )
 977                                         (void)close(ctrl);
 978
 979                                 memset(&sa, 0, sizeof(sa));
 980                                 sa.sa_handler = SIG_DFL;
 981                                 sigaction(SIGPIPE, &sa, NULL);
 982
 983                                 execv(sep->se_server, sep->se_argv);
 984                                 syslog_err_and_discard_dg(sep->se_socktype,
 985                                         "execv %s: %m", sep->se_server);
 986                         }
 987                 }
 988                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
 989                         close(ctrl);
 990             }
 991         }
 992 }
 993
 994
 995 /*
 996  * Internet services provided internally by inetd:
 997  */
 998 #define BUFSIZE 4096
 999
1000 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
1001 /* Echo service -- echo data back */
1002 static void echo_stream(int s, struct servtab *sep)
1003 {
1004         char buffer[BUFSIZE];
1005         int i;
1006
1007         setproctitle(sep->se_service, s);
1008         while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
1009             write(s, buffer, i) > 0)
1010                 ;
1011         exit(0);
1012 }
1013
1014 /* Echo service -- echo data back */
1015 static void echo_dg(int s, struct servtab *sep)
1016 {
1017         char buffer[BUFSIZE];
1018         int i;
1019         size_t size;
1020         struct sockaddr sa;
1021
1022         (void)sep;
1023
1024         size = sizeof(sa);
1025         if ((i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size)) < 0)
1026                 return;
1027         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1028 }
1029 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO */
1030
1031
1032 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
1033 /* Discard service -- ignore data */
1034 static void discard_stream(int s, struct servtab *sep)
1035 {
1036         char buffer[BUFSIZE];
1037
1038         setproctitle(sep->se_service, s);
1039         while ((errno = 0, read(s, buffer, sizeof(buffer)) > 0) ||
1040                         errno == EINTR)
1041                 ;
1042         exit(0);
1043 }
1044
1045 /* Discard service -- ignore data */
1046 static void discard_dg(int s, struct servtab *sep)
1047 {
1048         char buffer[BUFSIZE];
1049         (void)sep;
1050         read(s, buffer, sizeof(buffer));
1051 }
1052 #endif  /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD */
1053
1054
1055 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
1056 #include <ctype.h>
1057 #define LINESIZ 72
1058 static char ring[128];
1059 static char *endring;
1060
1061 static void initring(void)
1062 {
1063         int i;
1064
1065         endring = ring;
1066
1067         for (i = 0; i <= 128; ++i)
1068                 if (isprint(i))
1069                         *endring++ = i;
1070 }
1071
1072 /* Character generator */
1073 static void chargen_stream(int s, struct servtab *sep)
1074 {
1075         char *rs;
1076         int len;
1077         char text[LINESIZ+2];
1078
1079         setproctitle(sep->se_service, s);
1080
1081         if (!endring) {
1082                 initring();
1083                 rs = ring;
1084         }
1085
1086         text[LINESIZ] = '\r';
1087         text[LINESIZ + 1] = '\n';
1088         for (rs = ring;;) {
1089                 if ((len = endring - rs) >= LINESIZ)
1090                         memcpy(rs, text, LINESIZ);
1091                 else {
1092                         memcpy(rs, text, len);
1093                         memcpy(ring, text + len, LINESIZ - len);
1094                 }
1095                 if (++rs == endring)
1096                         rs = ring;
1097                 if (write(s, text, sizeof(text)) != sizeof(text))
1098                         break;
1099         }
1100         exit(0);
1101 }
1102
1103 /* Character generator */
1104 static void chargen_dg(int s, struct servtab *sep)
1105 {
1106         struct sockaddr sa;
1107         static char *rs;
1108         size_t len, size;
1109         char text[LINESIZ+2];
1110
1111         (void)sep;
1112
1113         if (endring == 0) {
1114                 initring();
1115                 rs = ring;
1116         }
1117
1118         size = sizeof(sa);
1119         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1120                 return;
1121
1122         if ((len = endring - rs) >= LINESIZ)
1123                 memcpy(rs, text, LINESIZ);
1124         else {
1125                 memcpy(rs, text, len);
1126                 memcpy(ring, text + len, LINESIZ - len);
1127         }
1128         if (++rs == endring)
1129                 rs = ring;
1130         text[LINESIZ] = '\r';
1131         text[LINESIZ + 1] = '\n';
1132         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1133 }
1134 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN */
1135
1136
1137 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
1138 /*
1139  * Return a machine readable date and time, in the form of the
1140  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1141  * returns the number of seconds since midnight, Jan 1, 1970,
1142  * we must add 2208988800 seconds to this figure to make up for
1143  * some seventy years Bell Labs was asleep.
1144  */
1145
1146 static long machtime(void)
1147 {
1148         struct timeval tv;
1149
1150         if (gettimeofday(&tv, (struct timezone *)0) < 0) {
1151                 fprintf(stderr, "Unable to get time of day\n");
1152                 return (0L);
1153         }
1154         return (htonl((long)tv.tv_sec + 2208988800UL));
1155 }
1156
1157 static void machtime_stream(int s, struct servtab *sep)
1158 {
1159         long result;
1160         (void)sep;
1161
1162         result = machtime();
1163         write(s, (char *) &result, sizeof(result));
1164 }
1165
1166 static void machtime_dg(int s, struct servtab *sep)
1167 {
1168         long result;
1169         struct sockaddr sa;
1170         size_t size;
1171         (void)sep;
1172
1173         size = sizeof(sa);
1174         if (recvfrom(s, (char *)&result, sizeof(result), 0, &sa, &size) < 0)
1175                 return;
1176         result = machtime();
1177         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1178 }
1179 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME */
1180
1181
1182 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
1183 /* Return human-readable time of day */
1184 static int human_readable_time_sprintf(char *buffer)
1185 {
1186         time_t clocc = time(NULL);
1187
1188         return sprintf(buffer, "%.24s\r\n", ctime(&clocc));
1189 }
1190
1191 static void daytime_stream(int s, struct servtab *sep)
1192 {
1193         char buffer[256];
1194         size_t st = human_readable_time_sprintf(buffer);
1195
1196         (void)sep;
1197
1198         write(s, buffer, st);
1199 }
1200
1201 /* Return human-readable time of day */
1202 static void daytime_dg(int s, struct servtab *sep)
1203 {
1204         char buffer[256];
1205         struct sockaddr sa;
1206         size_t size;
1207
1208         (void)sep;
1209
1210         size = sizeof(sa);
1211         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1212                 return;
1213         size = human_readable_time_sprintf(buffer);
1214         sendto(s, buffer, size, 0, &sa, sizeof(sa));
1215 }
1216 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME */