621 lines
12 KiB
C
621 lines
12 KiB
C
/*
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** $Id: identd.c,v 1.2 1994/02/04 23:17:56 cgd Exp $
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**
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** identd.c A TCP/IP link identification protocol server
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**
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** This program is in the public domain and may be used freely by anyone
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** who wants to.
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**
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** Last update: 22 April 1993
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**
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** Please send bug fixes/bug reports to: Peter Eriksson <pen@lysator.liu.se>
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*/
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#if defined(IRIX) || defined(SVR4) || defined(NeXT) || defined(__NetBSD__)
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# define SIGRETURN_TYPE void
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# define SIGRETURN_TYPE_IS_VOID
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#else
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# define SIGRETURN_TYPE int
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#endif
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#ifdef SVR4
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# define STRNET
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#endif
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#include <stdio.h>
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#include <ctype.h>
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#include <errno.h>
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#include <netdb.h>
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#include <signal.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#ifndef _AUX_SOURCE
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# include <sys/file.h>
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#endif
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#include <sys/time.h>
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#include <sys/wait.h>
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#include <pwd.h>
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#include <grp.h>
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#include <netinet/in.h>
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#ifndef HPUX7
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# include <arpa/inet.h>
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#endif
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#if defined(MIPS) || defined(BSD43)
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extern int errno;
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#endif
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#include "identd.h"
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#include "error.h"
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/* Antique unixes do not have these things defined... */
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#ifndef FD_SETSIZE
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# define FD_SETSIZE 256
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#endif
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#ifndef FD_SET
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# ifndef NFDBITS
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# define NFDBITS (sizeof(int) * NBBY) /* bits per mask */
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# endif
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# define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
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#endif
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#ifndef FD_ZERO
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# define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
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#endif
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extern char *version;
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extern void *calloc();
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extern void *malloc();
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char *path_unix = NULL;
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char *path_kmem = NULL;
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int verbose_flag = 0;
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int debug_flag = 0;
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int syslog_flag = 0;
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int multi_flag = 0;
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int other_flag = 0;
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int unknown_flag = 0;
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int number_flag = 0;
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int noident_flag = 0;
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int lport = 0;
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int fport = 0;
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char *charset_name = NULL;
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char *indirect_host = NULL;
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char *indirect_password = NULL;
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static int child_pid;
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#ifdef LOG_DAEMON
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static int syslog_facility = LOG_DAEMON;
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#endif
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/*
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** The structure passing convention for GCC is incompatible with
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** Suns own C compiler, so we define our own inet_ntoa() function.
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** (This should only affect GCC version 1 I think, a well, this works
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** for version 2 also so why bother.. :-)
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*/
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#if defined(__GNUC__) && defined(__sparc__)
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#ifdef inet_ntoa
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#undef inet_ntoa
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#endif
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char *inet_ntoa(ad)
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struct in_addr ad;
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{
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unsigned long int s_ad;
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int a, b, c, d;
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static char addr[20];
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s_ad = ad.s_addr;
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d = s_ad % 256;
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s_ad /= 256;
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c = s_ad % 256;
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s_ad /= 256;
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b = s_ad % 256;
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a = s_ad / 256;
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sprintf(addr, "%d.%d.%d.%d", a, b, c, d);
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return addr;
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}
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#endif
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/*
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** Return the name of the connecting host, or the IP number as a string.
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*/
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char *gethost(addr)
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struct in_addr *addr;
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{
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struct hostent *hp;
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hp = gethostbyaddr((char *) addr, sizeof(struct in_addr), AF_INET);
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if (hp)
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return hp->h_name;
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else
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return inet_ntoa(*addr);
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}
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/*
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** Exit cleanly after our time's up.
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*/
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static SIGRETURN_TYPE
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alarm_handler()
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{
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if (syslog_flag)
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syslog(LOG_DEBUG, "SIGALRM triggered, exiting");
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exit(0);
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}
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#if !defined(hpux) && !defined(__hpux) && !defined(SVR4) || defined(_CRAY)
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/*
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** This is used to clean up zombie child processes
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** if the -w or -b options are used.
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*/
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static SIGRETURN_TYPE
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child_handler()
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{
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#if defined(IRIX) || defined(NeXT)
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union wait status;
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#else
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int status;
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#endif
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while (wait3(&status, WNOHANG, NULL) > 0)
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;
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#ifndef SIGRETURN_TYPE_IS_VOID
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return 0;
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#endif
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}
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#endif
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char *clearmem(bp, len)
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char *bp;
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int len;
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{
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char *cp;
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cp = bp;
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while (len-- > 0)
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*cp++ = 0;
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return bp;
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}
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/*
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** Main entry point into this daemon
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*/
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int main(argc,argv)
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int argc;
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char *argv[];
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{
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int i, len;
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struct sockaddr_in sin;
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struct in_addr laddr, faddr;
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struct timeval tv;
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int background_flag = 0;
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int timeout = 0;
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char *portno = "113";
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char *bind_address = NULL;
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int set_uid = 0;
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int set_gid = 0;
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int inhibit_default_config = 0;
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int opt_count = 0; /* Count of option flags */
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#ifdef __convex__
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argc--; /* get rid of extra argument passed by inetd */
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#endif
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/*
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** Prescan the arguments for "-f<config-file>" switches
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*/
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inhibit_default_config = 0;
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for (i = 1; i < argc && argv[i][0] == '-'; i++)
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if (argv[i][1] == 'f')
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inhibit_default_config = 1;
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/*
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** Parse the default config file - if it exists
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*/
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if (!inhibit_default_config)
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parse_config(NULL, 1);
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/*
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** Parse the command line arguments
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*/
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for (i = 1; i < argc && argv[i][0] == '-'; i++) {
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opt_count++;
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switch (argv[i][1])
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{
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case 'b': /* Start as standalone daemon */
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background_flag = 1;
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break;
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case 'w': /* Start from Inetd, wait mode */
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background_flag = 2;
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break;
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case 'i': /* Start from Inetd, nowait mode */
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background_flag = 0;
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break;
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case 't':
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timeout = atoi(argv[i]+2);
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break;
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case 'p':
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portno = argv[i]+2;
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break;
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case 'a':
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bind_address = argv[i]+2;
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break;
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case 'u':
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if (isdigit(argv[i][2]))
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set_uid = atoi(argv[i]+2);
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else
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{
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struct passwd *pwd;
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pwd = getpwnam(argv[i]+2);
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if (!pwd)
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ERROR1("no such user (%s) for -u option", argv[i]+2);
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else
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{
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set_uid = pwd->pw_uid;
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set_gid = pwd->pw_gid;
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}
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}
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break;
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case 'g':
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if (isdigit(argv[i][2]))
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set_gid = atoi(argv[i]+2);
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else
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{
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struct group *grp;
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grp = getgrnam(argv[i]+2);
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if (!grp)
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ERROR1("no such group (%s) for -g option", argv[i]+2);
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else
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set_gid = grp->gr_gid;
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}
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break;
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case 'c':
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charset_name = argv[i]+2;
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break;
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case 'r':
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indirect_host = argv[i]+2;
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break;
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case 'l': /* Use the Syslog daemon for logging */
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syslog_flag++;
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break;
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case 'o':
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other_flag = 1;
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break;
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case 'e':
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unknown_flag = 1;
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break;
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case 'n':
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number_flag = 1;
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break;
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case 'V': /* Give version of this daemon */
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printf("[in.identd, version %s]\r\n", version);
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exit(0);
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break;
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case 'v': /* Be verbose */
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verbose_flag++;
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break;
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case 'd': /* Enable debugging */
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debug_flag++;
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break;
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case 'm': /* Enable multiline queries */
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multi_flag++;
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break;
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case 'N': /* Enable users ".noident" files */
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noident_flag++;
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break;
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}
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}
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#if defined(_AUX_SOURCE) || defined (SUNOS35)
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/* A/UX 2.0* & SunOS 3.5 calls us with an argument XXXXXXXX.YYYY
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** where XXXXXXXXX is the hexadecimal version of the callers
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** IP number, and YYYY is the port/socket or something.
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** It seems to be impossible to pass arguments to a daemon started
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** by inetd.
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**
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** Just in case it is started from something else, then we only
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** skip the argument if no option flags have been seen.
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*/
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if (opt_count == 0)
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argc--;
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#endif
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/*
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** Path to kernel namelist file specified on command line
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*/
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if (i < argc)
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path_unix = argv[i++];
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/*
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** Path to kernel memory device specified on command line
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*/
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if (i < argc)
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path_kmem = argv[i++];
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/*
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** Open the kernel memory device and read the nlist table
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*/
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if (k_open() < 0)
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ERROR("main: k_open");
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/*
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** Do the special handling needed for the "-b" flag
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*/
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if (background_flag == 1)
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{
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struct sockaddr_in addr;
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struct servent *sp;
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int fd;
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if (fork())
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exit(0);
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close(0);
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close(1);
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close(2);
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if (fork())
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exit(0);
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fd = socket(AF_INET, SOCK_STREAM, 0);
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if (fd == -1)
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ERROR("main: socket");
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if (fd != 0)
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dup2(fd, 0);
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clearmem(&addr, sizeof(addr));
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addr.sin_family = AF_INET;
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if (bind_address == NULL)
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addr.sin_addr.s_addr = htonl(INADDR_ANY);
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else
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{
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if (isdigit(bind_address[0]))
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addr.sin_addr.s_addr = inet_addr(bind_address);
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else
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{
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struct hostent *hp;
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hp = gethostbyname(bind_address);
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if (!hp)
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ERROR1("no such address (%s) for -a switch", bind_address);
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/* This is ugly, should use memcpy() or bcopy() but... */
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addr.sin_addr.s_addr = * (unsigned long *) (hp->h_addr);
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}
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}
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if (isdigit(portno[0]))
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addr.sin_port = htons(atoi(portno));
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else
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{
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sp = getservbyname(portno, "tcp");
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if (sp == NULL)
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ERROR1("main: getservbyname: %s", portno);
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addr.sin_port = sp->s_port;
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}
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if (bind(0, (struct sockaddr *) &addr, sizeof(addr)) < 0)
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ERROR("main: bind");
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if (listen(0, 3) < 0)
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ERROR("main: listen");
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}
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if (set_gid)
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if (setgid(set_gid) == -1)
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ERROR("main: setgid");
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if (set_uid)
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if (setuid(set_uid) == -1)
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ERROR("main: setuid");
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/*
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** Do some special handling if the "-b" or "-w" flags are used
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*/
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if (background_flag)
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{
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int nfds, fd;
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fd_set read_set;
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/*
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** Set up the SIGCHLD signal child termination handler so
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** that we can avoid zombie processes hanging around and
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** handle childs terminating before being able to complete the
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** handshake.
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*/
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#if (defined(SVR4) || defined(hpux) || defined(__hpux) || \
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defined(_CRAY) || defined(_AUX_SOURCE))
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signal(SIGCHLD, SIG_IGN);
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#else
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signal(SIGCHLD, (SIGRETURN_TYPE (*)()) child_handler);
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#endif
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/*
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** Loop and dispatch client handling processes
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*/
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do
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{
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/*
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** Terminate if we've been idle for 'timeout' seconds
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*/
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if (background_flag == 2 && timeout)
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{
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signal(SIGALRM, alarm_handler);
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alarm(timeout);
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}
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/*
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** Wait for a connection request to occur.
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** Ignore EINTR (Interrupted System Call).
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*/
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do
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{
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FD_ZERO(&read_set);
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FD_SET(0, &read_set);
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if (timeout)
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{
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tv.tv_sec = timeout;
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tv.tv_usec = 0;
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nfds = select(FD_SETSIZE, &read_set, NULL, NULL, &tv);
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}
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else
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nfds = select(FD_SETSIZE, &read_set, NULL, NULL, NULL);
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} while (nfds < 0 && errno == EINTR);
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/*
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** An error occured in select? Just die
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*/
|
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if (nfds < 0)
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ERROR("main: select");
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|
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/*
|
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** Timeout limit reached. Exit nicely
|
|
*/
|
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if (nfds == 0)
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exit(0);
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|
|
/*
|
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** Disable the alarm timeout
|
|
*/
|
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alarm(0);
|
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|
|
/*
|
|
** Accept the new client
|
|
*/
|
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fd = accept(0, NULL, NULL);
|
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if (fd == -1)
|
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ERROR1("main: accept. errno = %d", errno);
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|
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/*
|
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** And fork, then close the fd if we are the parent.
|
|
*/
|
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child_pid = fork();
|
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} while (child_pid && (close(fd), 1));
|
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|
|
/*
|
|
** We are now in child, the parent has returned to "do" above.
|
|
*/
|
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if (dup2(fd, 0) == -1)
|
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ERROR("main: dup2: failed fd 0");
|
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|
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if (dup2(fd, 1) == -1)
|
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ERROR("main: dup2: failed fd 1");
|
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|
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if (dup2(fd, 2) == -1)
|
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ERROR("main: dup2: failed fd 2");
|
|
}
|
|
|
|
/*
|
|
** Get foreign internet address
|
|
*/
|
|
len = sizeof(sin);
|
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if (getpeername(0, (struct sockaddr *) &sin, &len) == -1)
|
|
{
|
|
/*
|
|
** A user has tried to start us from the command line or
|
|
** the network link died, in which case this message won't
|
|
** reach to other end anyway, so lets give the poor user some
|
|
** errors.
|
|
*/
|
|
perror("in.identd: getpeername()");
|
|
exit(1);
|
|
}
|
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|
|
faddr = sin.sin_addr;
|
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|
|
|
|
/*
|
|
** Open the connection to the Syslog daemon if requested
|
|
*/
|
|
if (syslog_flag)
|
|
{
|
|
#ifdef LOG_DAEMON
|
|
openlog("identd", LOG_PID, syslog_facility);
|
|
#else
|
|
openlog("identd", LOG_PID);
|
|
#endif
|
|
|
|
syslog(LOG_INFO, "Connection from %s", gethost(&faddr));
|
|
}
|
|
|
|
|
|
/*
|
|
** Get local internet address
|
|
*/
|
|
len = sizeof(sin);
|
|
#ifdef ATTSVR4
|
|
if (t_getsockname(0, (struct sockaddr *) &sin, &len) == -1)
|
|
#else
|
|
if (getsockname(0, (struct sockaddr *) &sin, &len) == -1)
|
|
#endif
|
|
{
|
|
/*
|
|
** We can just die here, because if this fails then the
|
|
** network has died and we haven't got anyone to return
|
|
** errors to.
|
|
*/
|
|
exit(1);
|
|
}
|
|
laddr = sin.sin_addr;
|
|
|
|
|
|
/*
|
|
** Get the local/foreign port pair from the luser
|
|
*/
|
|
parse(stdin, &laddr, &faddr);
|
|
|
|
exit(0);
|
|
}
|