userapps/opensource/busybox/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 unsupported
  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
  94 #ifndef __linux__
  95 #ifndef RLIMIT_NOFILE
  96 #define RLIMIT_NOFILE   RLIMIT_OFILE
  97 #endif
  98 #endif
  99
 100 #include <sys/file.h>
 101 #include <sys/ioctl.h>
 102 #include <sys/param.h>
 103 #include <sys/resource.h>
 104 #include <sys/socket.h>
 105 #include <sys/stat.h>
 106 #include <sys/time.h>
 107 #include <sys/un.h>
 108 #include <sys/wait.h>
 109
 110 #include <netinet/in.h>
 111 #include <netinet/ip.h>
 112 #include <arpa/inet.h>
 113
 114 #include <errno.h>
 115 #include <signal.h>
 116 #include <netdb.h>
 117 #include <syslog.h>
 118 #include <stdio.h>
 119 #include <stdlib.h>
 120 #include <string.h>
 121 #include <getopt.h>
 122 #include <unistd.h>
 123 #include <stdarg.h>
 124 #include <time.h>
 125
 126 #ifndef OPEN_MAX
 127 #define OPEN_MAX        64
 128 #endif
 129
 130 #define _PATH_INETDCONF "/etc/inetd.conf"
 131 #define _PATH_INETDPID  "/var/run/inetd.pid"
 132
 133 #define TOOMANY         40              /* don't start more than TOOMANY */
 134 #define CNT_INTVL       60              /* servers in CNT_INTVL sec. */
 135 #define RETRYTIME       (60*10) /* retry after bind or server fail */
 136 #define MAXARGV         20
 137
 138 #define se_ctrladdr             se_un.se_un_ctrladdr
 139 #define se_ctrladdr_in  se_un.se_un_ctrladdr_in
 140 #define se_ctrladdr_un  se_un.se_un_ctrladdr_un
 141
 142 /* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
 143 #define FD_MARGIN       (8)
 144
 145 /* Check unsupporting builtin */
 146 #if defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO || \
 147         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD || \
 148         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME || \
 149         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME || \
 150         defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 151 # define INETD_FEATURE_ENABLED
 152 #endif
 153
 154 typedef struct servtab_s {
 155         char    *se_service;            /* name of service */
 156         int     se_socktype;            /* type of socket to use */
 157         int     se_family;              /* address family */
 158         char    *se_proto;              /* protocol used */
 159         short   se_wait;                /* single threaded server */
 160         short   se_checked;             /* looked at during merge */
 161         char    *se_user;               /* user name to run as */
 162         char    *se_group;              /* group name to run as */
 163 #ifdef INETD_FEATURE_ENABLED
 164         const struct  biltin *se_bi;    /* if built-in, description */
 165 #endif
 166         char    *se_server;             /* server program */
 167         char    *se_argv[MAXARGV+1];    /* program arguments */
 168         int     se_fd;                  /* open descriptor */
 169         union {
 170                 struct  sockaddr se_un_ctrladdr;
 171                 struct  sockaddr_in se_un_ctrladdr_in;
 172                 struct  sockaddr_un se_un_ctrladdr_un;
 173         } se_un;                        /* bound address */
 174         int     se_ctrladdr_size;
 175         int     se_max;                 /* max # of instances of this service */
 176         int     se_count;               /* number started since se_time */
 177         struct  timeval se_time;        /* start of se_count */
 178         struct  servtab_s *se_next;
 179 } servtab_t;
 180
 181 static servtab_t *servtab;
 182
 183 #ifdef INETD_FEATURE_ENABLED
 184 struct biltin {
 185         const char *bi_service;         /* internally provided service name */
 186         int bi_socktype;                /* type of socket supported */
 187         short bi_fork;          /* 1 if should fork before call */
 188         short bi_wait;          /* 1 if should wait for child */
 189         void (*bi_fn)(int, servtab_t *); /* fn which performs it */
 190 };
 191
 192     /* Echo received data */
 193 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
 194 static void echo_stream(int, servtab_t *);
 195 static void echo_dg(int, servtab_t *);
 196 #endif
 197     /* Internet /dev/null */
 198 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
 199 static void discard_stream(int, servtab_t *);
 200 static void discard_dg(int, servtab_t *);
 201 #endif
 202         /* Return 32 bit time since 1900 */
 203 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
 204 static void machtime_stream(int, servtab_t *);
 205 static void machtime_dg(int, servtab_t *);
 206 #endif
 207         /* Return human-readable time */
 208 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
 209 static void daytime_stream(int, servtab_t *);
 210 static void daytime_dg(int, servtab_t *);
 211 #endif
 212         /* Familiar character generator */
 213 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 214 static void chargen_stream(int, servtab_t *);
 215 static void chargen_dg(int, servtab_t *);
 216 #endif
 217
 218 static const struct biltin biltins[] = {
 219 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
 220         /* Echo received data */
 221         { "echo",               SOCK_STREAM,    1, 0,   echo_stream, },
 222         { "echo",               SOCK_DGRAM,     0, 0,   echo_dg, },
 223 #endif
 224 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
 225         /* Internet /dev/null */
 226         { "discard",    SOCK_STREAM,    1, 0,   discard_stream, },
 227         { "discard",    SOCK_DGRAM,     0, 0,   discard_dg, },
 228 #endif
 229 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
 230         /* Return 32 bit time since 1900 */
 231         { "time",               SOCK_STREAM,    0, 0,   machtime_stream, },
 232         { "time",               SOCK_DGRAM,     0, 0,   machtime_dg,     },
 233 #endif
 234 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
 235         /* Return human-readable time */
 236         { "daytime",    SOCK_STREAM,    0, 0,   daytime_stream, },
 237         { "daytime",    SOCK_DGRAM,     0, 0,   daytime_dg,     },
 238 #endif
 239 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
 240         /* Familiar character generator */
 241         { "chargen",    SOCK_STREAM,    1, 0,   chargen_stream, },
 242         { "chargen",    SOCK_DGRAM,     0, 0,   chargen_dg,     },
 243 #endif
 244         { NULL, 0, 0, 0, NULL }
 245 };
 246 #endif  /* INETD_FEATURE_ENABLED */
 247
 248 #ifdef RLIMIT_NOFILE
 249 static struct rlimit   rlim_ofile;
 250 #endif
 251
 252 /* Length of socket listen queue. Should be per-service probably. */
 253 static int      global_queuelen = 128;
 254
 255 static FILE *fconfig;
 256 static sigset_t blockmask;
 257 static sigset_t emptymask;
 258 static fd_set   allsock;
 259 static int      nsock;
 260 static int      maxsock;
 261 static int      timingout;
 262 static int      rlim_ofile_cur = OPEN_MAX;
 263 static const char *CONFIG = _PATH_INETDCONF;
 264
 265 static void
 266 syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
 267         __attribute__ ((noreturn, format (printf, 2, 3)));
 268
 269 static void
 270 syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
 271 {
 272         char buf[50];
 273         va_list p;
 274
 275         va_start(p, msg);
 276         vsyslog(LOG_ERR, msg, p);
 277         if (se_socktype != SOCK_STREAM)
 278                 recv(0, buf, sizeof (buf), 0);
 279         _exit(1);
 280 }
 281
 282 static char * inetd_strdup(const char *s)
 283 {
 284         char *ms = strdup(s);
 285
 286         if(ms == NULL)
 287                 syslog_err_and_discard_dg(SOCK_STREAM, "strdup: %m");
 288         return ms;
 289 }
 290
 291
 292 static servtab_t *getconfigent(void)
 293 {
 294         static servtab_t serv;
 295         servtab_t *sep = &serv;
 296         int argc;
 297         char *cp = NULL;
 298         char *cp_ptr;
 299         char *cp_ptr_ptr = NULL;
 300
 301 more:
 302         free(cp);
 303         cp = bb_get_chomped_line_from_file(fconfig);
 304         if (feof(fconfig)) {
 305                 free(cp);
 306                 return (NULL);
 307         }
 308         if ((cp == NULL) || (*cp == '#')) {
 309                 goto more;
 310         }
 311         /* make bind 0.0.0.0 and other zero default */
 312         memset((char *)sep, 0, sizeof *sep);
 313
 314         cp_ptr = strtok_r(cp, " \t", &cp_ptr_ptr);
 315         if (cp_ptr == NULL) {
 316                 /* Error */
 317                 goto more;
 318         }
 319         sep->se_service = inetd_strdup(cp_ptr);
 320
 321         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 322         if (cp_ptr == NULL) {
 323                 /* Error */
 324                 goto more;
 325         }
 326         if (strcmp(cp_ptr, "stream") == 0)
 327                 sep->se_socktype = SOCK_STREAM;
 328         else if (strcmp(cp_ptr, "dgram") == 0)
 329                 sep->se_socktype = SOCK_DGRAM;
 330         else if (strcmp(cp_ptr, "rdm") == 0)
 331                 sep->se_socktype = SOCK_RDM;
 332         else if (strcmp(cp_ptr, "seqpacket") == 0)
 333                 sep->se_socktype = SOCK_SEQPACKET;
 334         else if (strcmp(cp_ptr, "raw") == 0)
 335                 sep->se_socktype = SOCK_RAW;
 336         else
 337                 sep->se_socktype = -1;
 338
 339         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 340         if (cp_ptr == NULL) {
 341                 /* error */
 342                 goto more;
 343         }
 344         if (strcmp(cp_ptr, "unix") == 0) {
 345                 sep->se_family = AF_UNIX;
 346         } else {
 347                 if (strncmp(cp_ptr, "rpc/", 4) == 0) {
 348                         syslog(LOG_ERR, "%s: rpc services not supported",
 349                             sep->se_service);
 350                         goto more;
 351                 }
 352                 sep->se_family = AF_INET;
 353         }
 354         sep->se_proto = inetd_strdup(cp_ptr);
 355
 356         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 357         if (cp_ptr == NULL) {
 358                 /* error */
 359                 goto more;
 360         }
 361         {
 362                 char *s = strchr(cp_ptr, '.');
 363                 if (s) {
 364                         *s++ = '\0';
 365                         sep->se_max = atoi(s);
 366                 } else
 367                         sep->se_max = TOOMANY;
 368         }
 369         sep->se_wait = strcmp(cp_ptr, "wait") == 0;
 370
 371         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 372         if (cp_ptr == NULL) {
 373                 /* error */
 374                 goto more;
 375         }
 376
 377         sep->se_user = inetd_strdup(cp_ptr);
 378         {
 379                 char *cp_ptr2 = strchr(sep->se_user, '.');
 380
 381                 if (cp_ptr2) {
 382                         *cp_ptr2++ = '\0';
 383                 }
 384                 sep->se_group = cp_ptr2;
 385         }
 386
 387         cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
 388         if (cp_ptr == NULL) {
 389                 /* error */
 390                 goto more;
 391         }
 392         if (strcmp(cp_ptr, "internal") == 0) {
 393 #ifdef INETD_FEATURE_ENABLED
 394                 const struct biltin *bi;
 395
 396                 for (bi = biltins; bi->bi_service; bi++) {
 397                         if ((bi->bi_socktype == sep->se_socktype) &&
 398                             (strcmp(bi->bi_service, sep->se_service) == 0)) {
 399                                 break;
 400                         }
 401                 }
 402                 if (bi->bi_service == 0) {
 403                         syslog(LOG_ERR, "internal service %s unknown", sep->se_service);
 404                         goto more;
 405                 }
 406                 sep->se_bi = bi;
 407                 sep->se_wait = bi->bi_wait;
 408 #else
 409                 syslog(LOG_ERR, "internal service %s unknown", cp_ptr);
 410                 goto more;
 411 #endif
 412         }
 413 #ifdef INETD_FEATURE_ENABLED
 414         else {
 415                 sep->se_bi = NULL;
 416         }
 417 #endif
 418         sep->se_server = inetd_strdup(cp_ptr);
 419
 420         argc = 0;
 421         while ((cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr)) != NULL) {
 422                 if (argc < MAXARGV) {
 423                         sep->se_argv[argc++] = inetd_strdup(cp_ptr);
 424                 }
 425         }
 426         free(cp);
 427
 428         return (sep);
 429 }
 430
 431 static void freeconfig(servtab_t *cp)
 432 {
 433         int i;
 434
 435         free(cp->se_service);
 436         free(cp->se_proto);
 437         free(cp->se_user);
 438         /* Note: se_group is part of the newstr'ed se_user */
 439         free(cp->se_server);
 440         for (i = 0; i < MAXARGV; i++)
 441                 free(cp->se_argv[i]);
 442 }
 443
 444 #ifdef INETD_FEATURE_ENABLED
 445 static char **Argv;
 446 static char *LastArg;
 447
 448 static void setproctitle(char *a, int s)
 449 {
 450         size_t size;
 451         char *cp;
 452         struct sockaddr_in sn;
 453         char buf[80];
 454
 455         cp = Argv[0];
 456         size = sizeof(sn);
 457         if (getpeername(s, (struct sockaddr *)&sn, &size) == 0)
 458                 (void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sn.sin_addr));
 459         else
 460                 (void) sprintf(buf, "-%s", a);
 461         strncpy(cp, buf, LastArg - cp);
 462         cp += strlen(cp);
 463         while (cp < LastArg)
 464                 *cp++ = ' ';
 465 }
 466 #endif  /* INETD_FEATURE_ENABLED */
 467
 468
 469 static void setup(servtab_t *sep)
 470 {
 471         int on = 1;
 472
 473         if ((sep->se_fd = socket(sep->se_family, sep->se_socktype, 0)) < 0) {
 474                 syslog(LOG_ERR, "%s/%s: socket: %m",
 475                     sep->se_service, sep->se_proto);
 476                 return;
 477         }
 478         if (setsockopt(sep->se_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&on,
 479                             sizeof(on)) < 0)
 480                 syslog(LOG_ERR, "setsockopt (SO_REUSEADDR): %m");
 481         if (bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size) < 0) {
 482                 syslog(LOG_ERR, "%s/%s: bind: %m",
 483                     sep->se_service, sep->se_proto);
 484                 (void) close(sep->se_fd);
 485                 sep->se_fd = -1;
 486                 if (!timingout) {
 487                         timingout = 1;
 488                         alarm(RETRYTIME);
 489                 }
 490                 return;
 491         }
 492         if (sep->se_socktype == SOCK_STREAM)
 493                 listen(sep->se_fd, global_queuelen);
 494
 495         FD_SET(sep->se_fd, &allsock);
 496         nsock++;
 497         if (sep->se_fd > maxsock) {
 498                 maxsock = sep->se_fd;
 499                 if (maxsock > rlim_ofile_cur - FD_MARGIN) {
 500 #ifdef RLIMIT_NOFILE
 501 # define FD_CHUNK        32
 502                         struct rlimit rl;
 503
 504                         if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
 505                                 syslog(LOG_ERR, "getrlimit: %m");
 506                                 return;
 507                         }
 508                         rl.rlim_cur = rl.rlim_max < (rl.rlim_cur + FD_CHUNK) ? rl.rlim_max : (rl.rlim_cur + FD_CHUNK);
 509                         if (rl.rlim_cur <= rlim_ofile_cur) {
 510                                 syslog(LOG_ERR,
 511 # if _FILE_OFFSET_BITS == 64
 512                                         "bump_nofile: cannot extend file limit, max = %lld",
 513 # else
 514                                         "bump_nofile: cannot extend file limit, max = %ld",
 515 # endif
 516                                         rl.rlim_cur);
 517                                 return;
 518                         }
 519
 520                         if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
 521                                 syslog(LOG_ERR, "setrlimit: %m");
 522                                 return;
 523                         }
 524
 525                         rlim_ofile_cur = rl.rlim_cur;
 526                         return;
 527 #else
 528                         syslog(LOG_ERR, "bump_nofile: cannot extend file limit");
 529                         return;
 530 #endif  /* RLIMIT_NOFILE */
 531                 }
 532         }
 533 }
 534
 535 static void config(int signum)
 536 {
 537         servtab_t *sep, *cp, **sepp;
 538         sigset_t oldmask;
 539         unsigned n;
 540
 541         (void)signum;
 542
 543         if (fconfig != NULL) {
 544                 fseek(fconfig, 0L, L_SET);
 545         } else {
 546                 fconfig = fopen(CONFIG, "r");
 547                 if (fconfig == NULL) {
 548                         syslog(LOG_ERR, "%s: %m", CONFIG);
 549                         return;
 550                 }
 551         }
 552
 553         for (sep = servtab; sep; sep = sep->se_next)
 554                 sep->se_checked = 0;
 555         while ((cp = getconfigent()) != NULL) {
 556                 for (sep = servtab; sep; sep = sep->se_next)
 557                         if (strcmp(sep->se_service, cp->se_service) == 0 &&
 558                             strcmp(sep->se_proto, cp->se_proto) == 0)
 559                                 break;
 560                 if (sep != 0) {
 561                         int i;
 562
 563 #define SWAP(type, a, b) {type c=(type)a; (type)a=(type)b; (type)b=(type)c;}
 564
 565                         sigprocmask(SIG_BLOCK, &emptymask, &oldmask);
 566                         /*
 567                          * sep->se_wait may be holding the pid of a daemon
 568                          * that we're waiting for.  If so, don't overwrite
 569                          * it unless the config file explicitly says don't
 570                          * wait.
 571                          */
 572                         if (
 573 #ifdef INETD_FEATURE_ENABLED
 574                             cp->se_bi == 0 &&
 575 #endif
 576                             (sep->se_wait == 1 || cp->se_wait == 0))
 577                                 sep->se_wait = cp->se_wait;
 578                         if (cp->se_max != sep->se_max)
 579                                 SWAP(int, cp->se_max, sep->se_max);
 580                         if (cp->se_user)
 581                                 SWAP(char *, sep->se_user, cp->se_user);
 582                         if (cp->se_group)
 583                                 SWAP(char *, sep->se_group, cp->se_group);
 584                         if (cp->se_server)
 585                                 SWAP(char *, sep->se_server, cp->se_server);
 586                         for (i = 0; i < MAXARGV; i++)
 587                                 SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
 588 #undef SWAP
 589                         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 590                         // This freeconfig() is probably a bug, since it will try and free()
 591                         // each of the argv[] values, which are really just pointers
 592                         // into the middle of a single line buffer for the config file.
 593                         //freeconfig(cp);       // BUG?
 594                 } else {
 595                         sep = (servtab_t *)xmalloc(sizeof (*sep));
 596                         *sep = *cp;
 597                         sep->se_fd = -1;
 598                         sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
 599                         sep->se_next = servtab;
 600                         servtab = sep;
 601                         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 602                 }
 603                 sep->se_checked = 1;
 604
 605                 switch (sep->se_family) {
 606                 case AF_UNIX:
 607                         if (sep->se_fd != -1)
 608                                 break;
 609                         (void)unlink(sep->se_service);
 610                         n = strlen(sep->se_service);
 611                         if (n > sizeof(sep->se_ctrladdr_un.sun_path) - 1)
 612                                 n = sizeof(sep->se_ctrladdr_un.sun_path) - 1;
 613                         strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n);
 614                         sep->se_ctrladdr_un.sun_family = AF_UNIX;
 615                         sep->se_ctrladdr_size = n +
 616                                         sizeof sep->se_ctrladdr_un.sun_family;
 617                         setup(sep);
 618                         break;
 619                 case AF_INET:
 620                         sep->se_ctrladdr_in.sin_family = AF_INET;
 621                         sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
 622                         {
 623                                 u_short port = bb_lookup_port(sep->se_service, sep->se_proto, 0);
 624
 625                                 if (port == 0) {
 626                                         syslog(LOG_ERR,
 627                                             "%s/%s: unknown service",
 628                                             sep->se_service, sep->se_proto);
 629                                         continue;
 630                                 }
 631                                 if (port != sep->se_ctrladdr_in.sin_port) {
 632                                         sep->se_ctrladdr_in.sin_port = port;
 633                                         if (sep->se_fd != -1) {
 634                                                 FD_CLR(sep->se_fd, &allsock);
 635                                                 nsock--;
 636                                                 (void) close(sep->se_fd);
 637                                         }
 638                                         sep->se_fd = -1;
 639                                 }
 640                                 if (sep->se_fd == -1)
 641                                         setup(sep);
 642                         }
 643                 }
 644         }
 645         if (fconfig) {
 646                 (void) fclose(fconfig);
 647                 fconfig = NULL;
 648         }
 649         /*
 650          * Purge anything not looked at above.
 651          */
 652         sigprocmask(SIG_SETMASK, &blockmask, &oldmask);
 653         sepp = &servtab;
 654         while ((sep = *sepp) != NULL) {
 655                 if (sep->se_checked) {
 656                         sepp = &sep->se_next;
 657                         continue;
 658                 }
 659                 *sepp = sep->se_next;
 660                 if (sep->se_fd != -1) {
 661                         FD_CLR(sep->se_fd, &allsock);
 662                         nsock--;
 663                         (void) close(sep->se_fd);
 664                 }
 665                 if (sep->se_family == AF_UNIX)
 666                         (void)unlink(sep->se_service);
 667                 freeconfig(sep);
 668                 free((char *)sep);
 669         }
 670         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 671 }
 672
 673
 674
 675 static void reapchild(int signum)
 676 {
 677         int status;
 678         int pid;
 679         servtab_t *sep;
 680
 681         (void)signum;
 682         for (;;) {
 683                 pid = wait3(&status, WNOHANG, (struct rusage *)0);
 684                 if (pid <= 0)
 685                         break;
 686                 for (sep = servtab; sep; sep = sep->se_next)
 687                         if (sep->se_wait == pid) {
 688                                 if (WIFEXITED(status) && WEXITSTATUS(status))
 689                                         syslog(LOG_WARNING,
 690                                             "%s: exit status 0x%x",
 691                                             sep->se_server, WEXITSTATUS(status));
 692                                 else if (WIFSIGNALED(status))
 693                                         syslog(LOG_WARNING,
 694                                             "%s: exit signal 0x%x",
 695                                             sep->se_server, WTERMSIG(status));
 696                                 sep->se_wait = 1;
 697                                 FD_SET(sep->se_fd, &allsock);
 698                                 nsock++;
 699                         }
 700         }
 701 }
 702
 703 static void retry(int signum)
 704 {
 705         servtab_t *sep;
 706
 707         (void)signum;
 708         timingout = 0;
 709         for (sep = servtab; sep; sep = sep->se_next) {
 710                 if (sep->se_fd == -1) {
 711                         switch (sep->se_family) {
 712                         case AF_UNIX:
 713                         case AF_INET:
 714                                 setup(sep);
 715                                 break;
 716                         }
 717                 }
 718         }
 719 }
 720
 721 static void goaway(int signum)
 722 {
 723         servtab_t *sep;
 724
 725         (void)signum;
 726         for (sep = servtab; sep; sep = sep->se_next)
 727                 if (sep->se_fd != -1 && sep->se_family == AF_UNIX)
 728                         (void)unlink(sep->se_service);
 729         (void)unlink(_PATH_INETDPID);
 730         exit(0);
 731 }
 732
 733
 734
 735 extern int inetd_main(int argc, char *argv[])
 736 {
 737         servtab_t *sep;
 738         struct group *grp = NULL;
 739         struct sigaction sa;
 740         int pid;
 741         unsigned long opt;
 742         char *sq;
 743         gid_t gid;
 744
 745 #ifdef INETD_FEATURE_ENABLED
 746         extern char **environ;
 747 #endif
 748
 749         gid = getgid();
 750         setgroups(1, &gid);
 751
 752 #ifdef INETD_FEATURE_ENABLED
 753         Argv = argv;
 754         if (environ == 0 || *environ == 0)
 755                 environ = argv;
 756         while (*environ)
 757                 environ++;
 758         LastArg = environ[-1] + strlen(environ[-1]);
 759 #endif
 760
 761 #if defined(__uClinux__)
 762         opt = bb_getopt_ulflags(argc, argv, "q:f", &sq);
 763         if (!(opt & 2)) {
 764             daemon(0, 0);
 765             /* reexec for vfork() do continue parent */
 766             vfork_daemon_rexec(argc, argv, "-f");
 767         }
 768 #else
 769         opt = bb_getopt_ulflags(argc, argv, "q:", &sq);
 770         daemon(0, 0);
 771 #endif /* uClinux */
 772
 773         if(opt & 1) {
 774                         global_queuelen = atoi(sq);
 775                         if (global_queuelen < 8) global_queuelen=8;
 776                 }
 777         argc -= optind;
 778         argv += optind;
 779
 780         if (argc > 0)
 781                 CONFIG = argv[0];
 782
 783         openlog(bb_applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
 784         {
 785                 FILE *fp;
 786
 787                 if ((fp = fopen(_PATH_INETDPID, "w")) != NULL) {
 788                         fprintf(fp, "%u\n", getpid());
 789                         (void)fclose(fp);
 790                 }
 791         }
 792
 793 #ifdef RLIMIT_NOFILE
 794         if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
 795                 syslog(LOG_ERR, "getrlimit: %m");
 796         } else {
 797                 rlim_ofile_cur = rlim_ofile.rlim_cur;
 798                 if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
 799                         rlim_ofile_cur = OPEN_MAX;
 800         }
 801 #endif
 802
 803         config(0);
 804
 805         sigemptyset(&emptymask);
 806         sigemptyset(&blockmask);
 807         sigaddset(&blockmask, SIGCHLD);
 808         sigaddset(&blockmask, SIGHUP);
 809         sigaddset(&blockmask, SIGALRM);
 810
 811         memset(&sa, 0, sizeof(sa));
 812         sa.sa_mask = blockmask;
 813         sa.sa_handler = retry;
 814         sigaction(SIGALRM, &sa, NULL);
 815         sa.sa_handler = config;
 816         sigaction(SIGHUP, &sa, NULL);
 817         sa.sa_handler = reapchild;
 818         sigaction(SIGCHLD, &sa, NULL);
 819         sa.sa_handler = goaway;
 820         sigaction(SIGTERM, &sa, NULL);
 821         sa.sa_handler = goaway;
 822         sigaction(SIGINT, &sa,  NULL);
 823         sa.sa_handler = SIG_IGN;
 824         sigaction(SIGPIPE, &sa, NULL);
 825
 826         {
 827                 /* space for daemons to overwrite environment for ps */
 828 #define DUMMYSIZE       100
 829                 char dummy[DUMMYSIZE];
 830
 831                 (void)memset(dummy, 'x', DUMMYSIZE - 1);
 832                 dummy[DUMMYSIZE - 1] = '\0';
 833
 834                 (void)setenv("inetd_dummy", dummy, 1);
 835         }
 836
 837         for (;;) {
 838                 fd_set readable;
 839                 int     ctrl;
 840                 int n;
 841
 842                 if (nsock == 0) {
 843                         sigprocmask(SIG_BLOCK, &blockmask, NULL);
 844                         while (nsock == 0) {
 845                                 sigsuspend(&emptymask);
 846                         }
 847                         sigprocmask(SIG_SETMASK, &emptymask, NULL);
 848                 }
 849                 readable = allsock;
 850                 n = select(maxsock + 1, &readable, (fd_set *)0, (fd_set *)0, (struct timeval *)0);
 851                 if (n <= 0) {
 852                         if (n < 0 && errno != EINTR) {
 853                                 syslog(LOG_WARNING, "select: %m");
 854                         }
 855                         sleep(1);
 856                         continue;
 857             }
 858                 for (sep = servtab; n && sep; sep = sep->se_next) {
 859                         if (sep->se_fd != -1 && FD_ISSET(sep->se_fd, &readable)) {
 860                                 n--;
 861                                 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
 862                                         /* Fixed AGC */
 863                                         fcntl(sep->se_fd, F_SETFL, O_NDELAY);
 864                                         /* --------- */
 865                                         ctrl = accept(sep->se_fd, NULL, NULL);
 866                                         fcntl(sep->se_fd, F_SETFL, 0);
 867                                         if (ctrl < 0) {
 868                                                 if (errno == EINTR || errno == EWOULDBLOCK) {
 869                                                         continue;
 870                                                 }
 871                                                 syslog(LOG_WARNING, "accept (for %s): %m",
 872                                                 sep->se_service);
 873                                                 continue;
 874                                         }
 875                                 } else {
 876                                         ctrl = sep->se_fd;
 877                                 }
 878                                 sigprocmask(SIG_BLOCK, &blockmask, NULL);
 879                                 pid = 0;
 880 #ifdef INETD_FEATURE_ENABLED
 881                                 if (sep->se_bi == 0 || sep->se_bi->bi_fork)
 882 #endif
 883                                 {
 884                                         if (sep->se_count++ == 0) {
 885                                                 gettimeofday(&sep->se_time, (struct timezone *)0);
 886                                         }
 887                                         else if (sep->se_count >= sep->se_max) {
 888                                                 struct timeval now;
 889
 890                                                 gettimeofday(&now, (struct timezone *)0);
 891                                                 if (now.tv_sec - sep->se_time.tv_sec > CNT_INTVL) {
 892                                                         sep->se_time = now;
 893                                                         sep->se_count = 1;
 894                                                 } else {
 895                                                         syslog(LOG_ERR,
 896                                                                 "%s/%s server failing (looping), service terminated",
 897                                                                 sep->se_service, sep->se_proto);
 898                                                         FD_CLR(sep->se_fd, &allsock);
 899                                                         close(sep->se_fd);
 900                                                         sep->se_fd = -1;
 901                                                         sep->se_count = 0;
 902                                                         nsock--;
 903                                                         sigprocmask(SIG_SETMASK, &emptymask, NULL);
 904                                                         if (!timingout) {
 905                                                                 timingout = 1;
 906                                                                 alarm(RETRYTIME);
 907                                                         }
 908                                                         continue;
 909                                                 }
 910                                         }
 911                                         pid = fork();
 912                                         if (pid < 0) {
 913                                                 syslog(LOG_ERR, "fork: %m");
 914                                                 if (sep->se_socktype == SOCK_STREAM) {
 915                                                         close(ctrl);
 916                                                 }
 917                                                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 918                                                 sleep(1);
 919                                                 continue;
 920                                         }
 921                                         if (pid && sep->se_wait) {
 922                                                 sep->se_wait = pid;
 923                                                 FD_CLR(sep->se_fd, &allsock);
 924                                                 nsock--;
 925                                         }
 926                                 }
 927                                 sigprocmask(SIG_SETMASK, &emptymask, NULL);
 928                                 if (pid == 0) {
 929 #ifdef INETD_FEATURE_ENABLED
 930                                         if (sep->se_bi) {
 931                                                 (*sep->se_bi->bi_fn)(ctrl, sep);
 932                                         } else
 933 #endif
 934                                         {
 935                                                 struct passwd *pwd = getpwnam(sep->se_user);
 936                                                 if (pwd == NULL) {
 937                                                         syslog_err_and_discard_dg(
 938                                                                 sep->se_socktype,
 939                                                                 "getpwnam: %s: No such user",
 940                                                                 sep->se_user);
 941                                                 }
 942                                                 if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
 943                                                         syslog_err_and_discard_dg(sep->se_socktype,
 944                                                                 "getgrnam: %s: No such group", 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                                                         }
 962                                                         setgid((gid_t)pwd->pw_gid);
 963                                                         initgroups(pwd->pw_name, pwd->pw_gid);
 964                                                         setuid((uid_t)pwd->pw_uid);
 965                                                 } else if (sep->se_group) {
 966                                                         setgid((gid_t)grp->gr_gid);
 967                                                         setgroups(1, &grp->gr_gid);
 968                                                 }
 969                                                 dup2(ctrl, 0);
 970                                                 close(ctrl);
 971                                                 dup2(0, 1);
 972                                                 dup2(0, 2);
 973 #ifdef RLIMIT_NOFILE
 974                                                 if (rlim_ofile.rlim_cur != rlim_ofile_cur) {
 975                                                         if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
 976                                                                 syslog(LOG_ERR,"setrlimit: %m");
 977                                                         }
 978                                                 }
 979 #endif
 980                                                 for (ctrl = rlim_ofile_cur-1; --ctrl > 2; ) {
 981                                                         (void)close(ctrl);
 982                                                 }
 983                                                 memset(&sa, 0, sizeof(sa));
 984                                                 sa.sa_handler = SIG_DFL;
 985                                                 sigaction(SIGPIPE, &sa, NULL);
 986
 987                                                 execv(sep->se_server, sep->se_argv);
 988                                                 syslog_err_and_discard_dg(sep->se_socktype, "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
1000 /*
1001  * Internet services provided internally by inetd:
1002  */
1003 #define BUFSIZE 4096
1004
1005 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
1006 /* Echo service -- echo data back */
1007 static void echo_stream(int s, servtab_t *sep)
1008 {
1009         char buffer[BUFSIZE];
1010         int i;
1011
1012         setproctitle(sep->se_service, s);
1013         while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
1014             write(s, buffer, i) > 0)
1015                 ;
1016         exit(0);
1017 }
1018
1019 /* Echo service -- echo data back */
1020 static void echo_dg(int s, servtab_t *sep)
1021 {
1022         char buffer[BUFSIZE];
1023         int i;
1024         size_t size;
1025         struct sockaddr sa;
1026
1027         (void)sep;
1028
1029         size = sizeof(sa);
1030         if ((i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size)) < 0)
1031                 return;
1032         (void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
1033 }
1034 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO */
1035
1036
1037 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
1038 /* Discard service -- ignore data */
1039 static void discard_stream(int s, servtab_t *sep)
1040 {
1041         char buffer[BUFSIZE];
1042
1043         setproctitle(sep->se_service, s);
1044         while ((errno = 0, read(s, buffer, sizeof(buffer)) > 0) ||
1045                         errno == EINTR)
1046                 ;
1047         exit(0);
1048 }
1049
1050 /* Discard service -- ignore data */
1051 static void discard_dg(int s, servtab_t *sep)
1052 {
1053         char buffer[BUFSIZE];
1054         (void)sep;
1055         read(s, buffer, sizeof(buffer));
1056 }
1057 #endif  /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD */
1058
1059
1060 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
1061 #include <ctype.h>
1062 #define LINESIZ 72
1063 static char ring[128];
1064 static char *endring;
1065
1066 static void initring(void)
1067 {
1068         int i;
1069
1070         endring = ring;
1071
1072         for (i = 0; i <= 128; ++i)
1073                 if (isprint(i))
1074                         *endring++ = i;
1075 }
1076
1077 /* Character generator */
1078 static void chargen_stream(int s, servtab_t *sep)
1079 {
1080         char *rs;
1081         int len;
1082         char text[LINESIZ+2];
1083
1084         setproctitle(sep->se_service, s);
1085
1086         if (!endring) {
1087                 initring();
1088                 rs = ring;
1089         }
1090
1091         text[LINESIZ] = '\r';
1092         text[LINESIZ + 1] = '\n';
1093         for (rs = ring;;) {
1094                 if ((len = endring - rs) >= LINESIZ)
1095                         memcpy(rs, text, LINESIZ);
1096                 else {
1097                         memcpy(rs, text, len);
1098                         memcpy(ring, text + len, LINESIZ - len);
1099                 }
1100                 if (++rs == endring)
1101                         rs = ring;
1102                 if (write(s, text, sizeof(text)) != sizeof(text))
1103                         break;
1104         }
1105         exit(0);
1106 }
1107
1108 /* Character generator */
1109 static void chargen_dg(int s, servtab_t *sep)
1110 {
1111         struct sockaddr sa;
1112         static char *rs;
1113         size_t len, size;
1114         char text[LINESIZ+2];
1115
1116         (void)sep;
1117
1118         if (endring == 0) {
1119                 initring();
1120                 rs = ring;
1121         }
1122
1123         size = sizeof(sa);
1124         if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
1125                 return;
1126
1127         if ((len = endring - rs) >= LINESIZ)
1128                 memcpy(rs, text, LINESIZ);
1129         else {
1130                 memcpy(rs, text, len);
1131                 memcpy(ring, text + len, LINESIZ - len);
1132         }
1133         if (++rs == endring)
1134                 rs = ring;
1135         text[LINESIZ] = '\r';
1136         text[LINESIZ + 1] = '\n';
1137         (void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
1138 }
1139 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN */
1140
1141
1142 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
1143 /*
1144  * Return a machine readable date and time, in the form of the
1145  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
1146  * returns the number of seconds since midnight, Jan 1, 1970,
1147  * we must add 2208988800 seconds to this figure to make up for
1148  * some seventy years Bell Labs was asleep.
1149  */
1150
1151 static long machtime(void)
1152 {
1153         struct timeval tv;
1154
1155         if (gettimeofday(&tv, (struct timezone *)0) < 0) {
1156                 fprintf(stderr, "Unable to get time of day\n");
1157                 return (0L);
1158         }
1159         return (htonl((long)tv.tv_sec + 2208988800UL));
1160 }
1161
1162 static void machtime_stream(int s, servtab_t *sep)
1163 {
1164         long result;
1165         (void)sep;
1166
1167         result = machtime();
1168         write(s, (char *) &result, sizeof(result));
1169 }
1170
1171 static void machtime_dg(int s, servtab_t *sep)
1172 {
1173         long result;
1174         struct sockaddr sa;
1175         size_t size;
1176         (void)sep;
1177
1178         size = sizeof(sa);
1179         if (recvfrom(s, (char *)&result, sizeof(result), 0, &sa, &size) < 0)
1180                 return;
1181         result = machtime();
1182         (void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
1183 }
1184 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME */
1185
1186
1187 #ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
1188 /* Return human-readable time of day */
1189 static int human_readable_time_sprintf(char *buffer)
1190 {
1191         time_t clocc = time(NULL);
1192
1193         return sprintf(buffer, "%.24s\r\n", ctime(&clocc));
1194 }
1195
1196 static void daytime_stream(int s, servtab_t *sep)
1197 {
1198         char buffer[256];
1199         size_t st = human_readable_time_sprintf(buffer);
1200
1201         (void)sep;
1202
1203         write(s, buffer, st);
1204 }
1205
1206 /* Return human-readable time of day */
1207 static void daytime_dg(int s, servtab_t *sep)
1208 {
1209         char buffer[256];
1210         struct sockaddr sa;
1211         size_t size;
1212
1213         (void)sep;
1214
1215         size = sizeof(sa);
1216         if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
1217                 return;
1218         size = human_readable_time_sprintf(buffer);
1219         sendto(s, buffer, size, 0, &sa, sizeof(sa));
1220 }
1221 #endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME */