NetBSD/libexec/identd/identd.c

620 lines
12 KiB
C

/*
** $Id: identd.c,v 1.5 1995/06/07 17:14:21 cgd Exp $
**
** identd.c A TCP/IP link identification protocol server
**
** This program is in the public domain and may be used freely by anyone
** who wants to.
**
** Last update: 22 April 1993
**
** Please send bug fixes/bug reports to: Peter Eriksson <pen@lysator.liu.se>
*/
#if defined(IRIX) || defined(SVR4) || defined(NeXT) || defined(__NetBSD__)
# define SIGRETURN_TYPE void
# define SIGRETURN_TYPE_IS_VOID
#else
# define SIGRETURN_TYPE int
#endif
#ifdef SVR4
# define STRNET
#endif
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifndef _AUX_SOURCE
# include <sys/file.h>
#endif
#include <sys/time.h>
#include <sys/wait.h>
#include <pwd.h>
#include <grp.h>
#include <netinet/in.h>
#ifndef HPUX7
# include <arpa/inet.h>
#endif
#if defined(MIPS) || defined(BSD43)
extern int errno;
#endif
#include "identd.h"
#include "error.h"
/* Antique unixes do not have these things defined... */
#ifndef FD_SETSIZE
# define FD_SETSIZE 256
#endif
#ifndef FD_SET
# ifndef NFDBITS
# define NFDBITS (sizeof(int) * NBBY) /* bits per mask */
# endif
# define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
#endif
#ifndef FD_ZERO
# define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
#endif
extern char *version;
extern void *calloc();
extern void *malloc();
char *path_unix = NULL;
char *path_kmem = NULL;
int verbose_flag = 0;
int debug_flag = 0;
int syslog_flag = 0;
int multi_flag = 0;
int other_flag = 0;
int unknown_flag = 0;
int number_flag = 0;
int noident_flag = 0;
int lport = 0;
int fport = 0;
char *charset_name = NULL;
char *indirect_host = NULL;
char *indirect_password = NULL;
static int child_pid;
#ifdef LOG_DAEMON
static int syslog_facility = LOG_DAEMON;
#endif
/*
** The structure passing convention for GCC is incompatible with
** Suns own C compiler, so we define our own inet_ntoa() function.
** (This should only affect GCC version 1 I think, a well, this works
** for version 2 also so why bother.. :-)
*/
#if defined(__GNUC__) && defined(__sparc__)
#ifdef inet_ntoa
#undef inet_ntoa
#endif
char *inet_ntoa(ad)
struct in_addr ad;
{
unsigned long int s_ad;
int a, b, c, d;
static char addr[20];
s_ad = ad.s_addr;
d = s_ad % 256;
s_ad /= 256;
c = s_ad % 256;
s_ad /= 256;
b = s_ad % 256;
a = s_ad / 256;
sprintf(addr, "%d.%d.%d.%d", a, b, c, d);
return addr;
}
#endif
/*
** Return the name of the connecting host, or the IP number as a string.
*/
char *gethost(addr)
struct in_addr *addr;
{
struct hostent *hp;
hp = gethostbyaddr((char *) addr, sizeof(struct in_addr), AF_INET);
if (hp)
return hp->h_name;
else
return inet_ntoa(*addr);
}
/*
** Exit cleanly after our time's up.
*/
static SIGRETURN_TYPE
alarm_handler()
{
if (syslog_flag)
syslog(LOG_DEBUG, "SIGALRM triggered, exiting");
exit(0);
}
#if !defined(hpux) && !defined(__hpux) && !defined(SVR4) || defined(_CRAY)
/*
** This is used to clean up zombie child processes
** if the -w or -b options are used.
*/
static SIGRETURN_TYPE
child_handler()
{
#if defined(IRIX) || defined(NeXT)
union wait status;
#else
int status;
#endif
while (wait3(&status, WNOHANG, NULL) > 0)
;
#ifndef SIGRETURN_TYPE_IS_VOID
return 0;
#endif
}
#endif
char *clearmem(bp, len)
char *bp;
int len;
{
char *cp;
cp = bp;
while (len-- > 0)
*cp++ = 0;
return bp;
}
/*
** Main entry point into this daemon
*/
int main(argc,argv)
int argc;
char *argv[];
{
int i, len;
struct sockaddr_in sin;
struct in_addr laddr, faddr;
struct timeval tv;
int background_flag = 0;
int timeout = 0;
char *portno = "113";
char *bind_address = NULL;
int set_uid = 0;
int set_gid = 0;
int inhibit_default_config = 0;
int opt_count = 0; /* Count of option flags */
#ifdef __convex__
argc--; /* get rid of extra argument passed by inetd */
#endif
/*
** Prescan the arguments for "-f<config-file>" switches
*/
inhibit_default_config = 0;
for (i = 1; i < argc && argv[i][0] == '-'; i++)
if (argv[i][1] == 'f')
inhibit_default_config = 1;
/*
** Parse the default config file - if it exists
*/
if (!inhibit_default_config)
parse_config(NULL, 1);
/*
** Parse the command line arguments
*/
for (i = 1; i < argc && argv[i][0] == '-'; i++) {
opt_count++;
switch (argv[i][1])
{
case 'b': /* Start as standalone daemon */
background_flag = 1;
break;
case 'w': /* Start from Inetd, wait mode */
background_flag = 2;
break;
case 'i': /* Start from Inetd, nowait mode */
background_flag = 0;
break;
case 't':
timeout = atoi(argv[i]+2);
break;
case 'p':
portno = argv[i]+2;
break;
case 'a':
bind_address = argv[i]+2;
break;
case 'u':
if (isdigit(argv[i][2]))
set_uid = atoi(argv[i]+2);
else
{
struct passwd *pwd;
pwd = getpwnam(argv[i]+2);
if (!pwd)
ERROR1("no such user (%s) for -u option", argv[i]+2);
else
{
set_uid = pwd->pw_uid;
set_gid = pwd->pw_gid;
}
}
break;
case 'g':
if (isdigit(argv[i][2]))
set_gid = atoi(argv[i]+2);
else
{
struct group *grp;
grp = getgrnam(argv[i]+2);
if (!grp)
ERROR1("no such group (%s) for -g option", argv[i]+2);
else
set_gid = grp->gr_gid;
}
break;
case 'c':
charset_name = argv[i]+2;
break;
case 'r':
indirect_host = argv[i]+2;
break;
case 'l': /* Use the Syslog daemon for logging */
syslog_flag++;
break;
case 'o':
other_flag = 1;
break;
case 'e':
unknown_flag = 1;
break;
case 'n':
number_flag = 1;
break;
case 'V': /* Give version of this daemon */
printf("[in.identd, version %s]\r\n", version);
exit(0);
break;
case 'v': /* Be verbose */
verbose_flag++;
break;
case 'd': /* Enable debugging */
debug_flag++;
break;
case 'm': /* Enable multiline queries */
multi_flag++;
break;
case 'N': /* Enable users ".noident" files */
noident_flag++;
break;
}
}
#if defined(_AUX_SOURCE) || defined (SUNOS35)
/* A/UX 2.0* & SunOS 3.5 calls us with an argument XXXXXXXX.YYYY
** where XXXXXXXXX is the hexadecimal version of the callers
** IP number, and YYYY is the port/socket or something.
** It seems to be impossible to pass arguments to a daemon started
** by inetd.
**
** Just in case it is started from something else, then we only
** skip the argument if no option flags have been seen.
*/
if (opt_count == 0)
argc--;
#endif
/*
** Path to kernel namelist file specified on command line
*/
if (i < argc)
path_unix = argv[i++];
/*
** Path to kernel memory device specified on command line
*/
if (i < argc)
path_kmem = argv[i++];
/*
** Open the kernel memory device and read the nlist table
*/
if (k_open() < 0)
ERROR("main: k_open");
/*
** Do the special handling needed for the "-b" flag
*/
if (background_flag == 1)
{
struct sockaddr_in addr;
struct servent *sp;
int fd;
if (fork())
exit(0);
close(0);
close(1);
close(2);
if (fork())
exit(0);
fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd == -1)
ERROR("main: socket");
if (fd != 0)
dup2(fd, 0);
clearmem(&addr, sizeof(addr));
addr.sin_len = sizeof(struct sockaddr_in);
addr.sin_family = AF_INET;
if (bind_address == NULL)
addr.sin_addr.s_addr = htonl(INADDR_ANY);
else
{
if (inet_aton(bind_address, &addr.sin_addr) == 0)
{
struct hostent *hp;
hp = gethostbyname(bind_address);
if (!hp)
ERROR1("no such address (%s) for -a switch", bind_address);
memcpy(&addr.sin_addr, hp->h_addr, sizeof(addr.sin_addr));
}
}
if (isdigit(portno[0]))
addr.sin_port = htons(atoi(portno));
else
{
sp = getservbyname(portno, "tcp");
if (sp == NULL)
ERROR1("main: getservbyname: %s", portno);
addr.sin_port = sp->s_port;
}
if (bind(0, (struct sockaddr *) &addr, sizeof(addr)) < 0)
ERROR("main: bind");
if (listen(0, 3) < 0)
ERROR("main: listen");
}
if (set_gid)
if (setgid(set_gid) == -1)
ERROR("main: setgid");
if (set_uid)
if (setuid(set_uid) == -1)
ERROR("main: setuid");
/*
** Do some special handling if the "-b" or "-w" flags are used
*/
if (background_flag)
{
int nfds, fd;
fd_set read_set;
/*
** Set up the SIGCHLD signal child termination handler so
** that we can avoid zombie processes hanging around and
** handle childs terminating before being able to complete the
** handshake.
*/
#if (defined(SVR4) || defined(hpux) || defined(__hpux) || \
defined(_CRAY) || defined(_AUX_SOURCE))
signal(SIGCHLD, SIG_IGN);
#else
signal(SIGCHLD, (SIGRETURN_TYPE (*)()) child_handler);
#endif
/*
** Loop and dispatch client handling processes
*/
do
{
/*
** Terminate if we've been idle for 'timeout' seconds
*/
if (background_flag == 2 && timeout)
{
signal(SIGALRM, alarm_handler);
alarm(timeout);
}
/*
** Wait for a connection request to occur.
** Ignore EINTR (Interrupted System Call).
*/
do
{
FD_ZERO(&read_set);
FD_SET(0, &read_set);
if (timeout)
{
tv.tv_sec = timeout;
tv.tv_usec = 0;
nfds = select(FD_SETSIZE, &read_set, NULL, NULL, &tv);
}
else
nfds = select(FD_SETSIZE, &read_set, NULL, NULL, NULL);
} while (nfds < 0 && errno == EINTR);
/*
** An error occured in select? Just die
*/
if (nfds < 0)
ERROR("main: select");
/*
** Timeout limit reached. Exit nicely
*/
if (nfds == 0)
exit(0);
/*
** Disable the alarm timeout
*/
alarm(0);
/*
** Accept the new client
*/
fd = accept(0, NULL, NULL);
if (fd == -1)
ERROR1("main: accept. errno = %d", errno);
/*
** And fork, then close the fd if we are the parent.
*/
child_pid = fork();
} while (child_pid && (close(fd), 1));
/*
** We are now in child, the parent has returned to "do" above.
*/
if (dup2(fd, 0) == -1)
ERROR("main: dup2: failed fd 0");
if (dup2(fd, 1) == -1)
ERROR("main: dup2: failed fd 1");
if (dup2(fd, 2) == -1)
ERROR("main: dup2: failed fd 2");
}
/*
** Get foreign internet address
*/
len = sizeof(sin);
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);
}
faddr = sin.sin_addr;
/*
** 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);
}