inetd.c

早期freebsd实现

		return;
	}
	if (sep->se_socktype == SOCK_STREAM)
		listen(sep->se_fd, 10);
	FD_SET(sep->se_fd, &allsock);
	nsock++;
	if (sep->se_fd > maxsock)
		maxsock = sep->se_fd;
	if (debug) {
		fprintf(stderr, "registered %s on %d\n",
			sep->se_server, sep->se_fd);
	}
}

/*
 * Finish with a service and its socket.
 */
void
close_sep(sep)
	struct servtab *sep;
{
	if (sep->se_fd >= 0) {
		nsock--;
		FD_CLR(sep->se_fd, &allsock);
		(void) close(sep->se_fd);
		sep->se_fd = -1;
	}
	sep->se_count = 0;
	/*
	 * Don't keep the pid of this running deamon: when reapchild()
	 * reaps this pid, it would erroneously increment nsock.
	 */
	if (sep->se_wait > 1)
		sep->se_wait = 1;
}

struct servtab *
enter(cp)
	struct servtab *cp;
{
	struct servtab *sep;
	long omask;

	sep = (struct servtab *)malloc(sizeof (*sep));
	if (sep == (struct servtab *)0) {
		syslog(LOG_ERR, "Out of memory.");
		exit(-1);
	}
	*sep = *cp;
	sep->se_fd = -1;
	omask = sigblock(SIGBLOCK);
	sep->se_next = servtab;
	servtab = sep;
	sigsetmask(omask);
	return (sep);
}

FILE	*fconfig = NULL;
struct	servtab serv;
char	line[LINE_MAX];

int
setconfig()
{

	if (fconfig != NULL) {
		fseek(fconfig, 0L, SEEK_SET);
		return (1);
	}
	fconfig = fopen(CONFIG, "r");
	return (fconfig != NULL);
}

void
endconfig()
{
	if (fconfig) {
		(void) fclose(fconfig);
		fconfig = NULL;
	}
}

struct servtab *
getconfigent()
{
	struct servtab *sep = &serv;
	int argc;
	char *cp, *arg;
	static char TCPMUX_TOKEN[] = "tcpmux/";
#define MUX_LEN		(sizeof(TCPMUX_TOKEN)-1)

more:
	while ((cp = nextline(fconfig)) && (*cp == '#' || *cp == '\0'))
		;
	if (cp == NULL)
		return ((struct servtab *)0);
	/*
	 * clear the static buffer, since some fields (se_ctrladdr,
	 * for example) don't get initialized here.
	 */
	memset((caddr_t)sep, 0, sizeof *sep);
	arg = skip(&cp);
	if (cp == NULL) {
		/* got an empty line containing just blanks/tabs. */
		goto more;
	}
	if (strncmp(arg, TCPMUX_TOKEN, MUX_LEN) == 0) {
		char *c = arg + MUX_LEN;
		if (*c == '+') {
			sep->se_type = MUXPLUS_TYPE;
			c++;
		} else
			sep->se_type = MUX_TYPE;
		sep->se_service = newstr(c);
	} else {
		sep->se_service = newstr(arg);
		sep->se_type = NORM_TYPE;
	}
	arg = sskip(&cp);
	if (strcmp(arg, "stream") == 0)
		sep->se_socktype = SOCK_STREAM;
	else if (strcmp(arg, "dgram") == 0)
		sep->se_socktype = SOCK_DGRAM;
	else if (strcmp(arg, "rdm") == 0)
		sep->se_socktype = SOCK_RDM;
	else if (strcmp(arg, "seqpacket") == 0)
		sep->se_socktype = SOCK_SEQPACKET;
	else if (strcmp(arg, "raw") == 0)
		sep->se_socktype = SOCK_RAW;
	else
		sep->se_socktype = -1;
	sep->se_proto = newstr(sskip(&cp));
	arg = sskip(&cp);
	sep->se_wait = strcmp(arg, "wait") == 0;
	if (ISMUX(sep)) {
		/*
		 * Silently enforce "nowait" for TCPMUX services since
		 * they don't have an assigned port to listen on.
		 */
		sep->se_wait = 0;

		if (strcmp(sep->se_proto, "tcp")) {
			syslog(LOG_ERR, 
				"%s: bad protocol for tcpmux service %s",
				CONFIG, sep->se_service);
			goto more;
		}
		if (sep->se_socktype != SOCK_STREAM) {
			syslog(LOG_ERR, 
				"%s: bad socket type for tcpmux service %s",
				CONFIG, sep->se_service);
			goto more;
		}
	}
	sep->se_user = newstr(sskip(&cp));
	sep->se_server = newstr(sskip(&cp));
	if (strcmp(sep->se_server, "internal") == 0) {
		struct biltin *bi;

		for (bi = biltins; bi->bi_service; bi++)
			if (bi->bi_socktype == sep->se_socktype &&
			    strcmp(bi->bi_service, sep->se_service) == 0)
				break;
		if (bi->bi_service == 0) {
			syslog(LOG_ERR, "internal service %s unknown",
				sep->se_service);
			goto more;
		}
		sep->se_bi = bi;
		sep->se_wait = bi->bi_wait;
	} else
		sep->se_bi = NULL;
	argc = 0;
	for (arg = skip(&cp); cp; arg = skip(&cp))
		if (argc < MAXARGV)
			sep->se_argv[argc++] = newstr(arg);
	while (argc <= MAXARGV)
		sep->se_argv[argc++] = NULL;
	return (sep);
}

void
freeconfig(cp)
	struct servtab *cp;
{
	int i;

	if (cp->se_service)
		free(cp->se_service);
	if (cp->se_proto)
		free(cp->se_proto);
	if (cp->se_user)
		free(cp->se_user);
	if (cp->se_server)
		free(cp->se_server);
	for (i = 0; i < MAXARGV; i++)
		if (cp->se_argv[i])
			free(cp->se_argv[i]);
}


/*
 * Safe skip - if skip returns null, log a syntax error in the
 * configuration file and exit.
 */
char *
sskip(cpp)
	char **cpp;
{
	char *cp;

	cp = skip(cpp);
	if (cp == NULL) {
		syslog(LOG_ERR, "%s: syntax error", CONFIG);
		exit(-1);
	}
	return (cp);
}

char *
skip(cpp)
	char **cpp;
{
	char *cp = *cpp;
	char *start;

again:
	while (*cp == ' ' || *cp == '\t')
		cp++;
	if (*cp == '\0') {
		int c;

		c = getc(fconfig);
		(void) ungetc(c, fconfig);
		if (c == ' ' || c == '\t')
			if (cp = nextline(fconfig))
				goto again;
		*cpp = (char *)0;
		return ((char *)0);
	}
	start = cp;
	while (*cp && *cp != ' ' && *cp != '\t')
		cp++;
	if (*cp != '\0')
		*cp++ = '\0';
	*cpp = cp;
	return (start);
}

char *
nextline(fd)
	FILE *fd;
{
	char *cp;

	if (fgets(line, sizeof (line), fd) == NULL)
		return ((char *)0);
	cp = strchr(line, '\n');
	if (cp)
		*cp = '\0';
	return (line);
}

char *
newstr(cp)
	char *cp;
{
	if (cp = strdup(cp ? cp : ""))
		return (cp);
	syslog(LOG_ERR, "strdup: %m");
	exit(-1);
}

void
setproctitle(a, s)
	char *a;
	int s;
{
	int size;
	char *cp;
	struct sockaddr_in sin;
	char buf[80];

	cp = Argv[0];
	size = sizeof(sin);
	if (getpeername(s, (struct sockaddr *)&sin, &size) == 0)
		(void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sin.sin_addr)); 
	else
		(void) sprintf(buf, "-%s", a); 
	strncpy(cp, buf, LastArg - cp);
	cp += strlen(cp);
	while (cp < LastArg)
		*cp++ = ' ';
}

/*
 * Internet services provided internally by inetd:
 */
#define	BUFSIZE	8192

/* ARGSUSED */
void
echo_stream(s, sep)		/* Echo service -- echo data back */
	int s;
	struct servtab *sep;
{
	char buffer[BUFSIZE];
	int i;

	setproctitle(sep->se_service, s);
	while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
	    write(s, buffer, i) > 0)
		;
	exit(0);
}

/* ARGSUSED */
void
echo_dg(s, sep)			/* Echo service -- echo data back */
	int s;
	struct servtab *sep;
{
	char buffer[BUFSIZE];
	int i, size;
	struct sockaddr sa;

	size = sizeof(sa);
	if ((i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size)) < 0)
		return;
	(void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
}

/* ARGSUSED */
void
discard_stream(s, sep)		/* Discard service -- ignore data */
	int s;
	struct servtab *sep;
{
	int ret;
	char buffer[BUFSIZE];

	setproctitle(sep->se_service, s);
	while (1) {
		while ((ret = read(s, buffer, sizeof(buffer))) > 0)
			;
		if (ret == 0 || errno != EINTR)
			break;
	}
	exit(0);
}

/* ARGSUSED */
void
discard_dg(s, sep)		/* Discard service -- ignore data */
	int s;
	struct servtab *sep;
{
	char buffer[BUFSIZE];

	(void) read(s, buffer, sizeof(buffer));
}

#include <ctype.h>
#define LINESIZ 72
char ring[128];
char *endring;

void
initring()
{
	int i;

	endring = ring;

	for (i = 0; i <= 128; ++i)
		if (isprint(i))
			*endring++ = i;
}

/* ARGSUSED */
void
chargen_stream(s, sep)		/* Character generator */
	int s;
	struct servtab *sep;
{
	int len;
	char *rs, text[LINESIZ+2];

	setproctitle(sep->se_service, s);

	if (!endring) {
		initring();
		rs = ring;
	}

	text[LINESIZ] = '\r';
	text[LINESIZ + 1] = '\n';
	for (rs = ring;;) {
		if ((len = endring - rs) >= LINESIZ)
			memmove(text, rs, LINESIZ);
		else {
			memmove(text, rs, len);
			memmove(text + len, ring, LINESIZ - len);
		}
		if (++rs == endring)
			rs = ring;
		if (write(s, text, sizeof(text)) != sizeof(text))
			break;
	}
	exit(0);
}

/* ARGSUSED */
void
chargen_dg(s, sep)		/* Character generator */
	int s;
	struct servtab *sep;
{
	struct sockaddr sa;
	static char *rs;
	int len, size;
	char text[LINESIZ+2];

	if (endring == 0) {
		initring();
		rs = ring;
	}

	size = sizeof(sa);
	if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
		return;

	if ((len = endring - rs) >= LINESIZ)
		memmove(text, rs, LINESIZ);
	else {
		memmove(text, rs, len);
		memmove(text + len, ring, LINESIZ - len);
	}
	if (++rs == endring)
		rs = ring;
	text[LINESIZ] = '\r';
	text[LINESIZ + 1] = '\n';
	(void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
}

/*
 * Return a machine readable date and time, in the form of the
 * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
 * returns the number of seconds since midnight, Jan 1, 1970,
 * we must add 2208988800 seconds to this figure to make up for
 * some seventy years Bell Labs was asleep.
 */

long
machtime()
{
	struct timeval tv;

	if (gettimeofday(&tv, (struct timezone *)0) < 0) {
		if (debug)
			fprintf(stderr, "Unable to get time of day\n");
		return (0L);
	}
#define	OFFSET ((u_long)25567 * 24*60*60)
	return (htonl((long)(tv.tv_sec + OFFSET)));
#undef OFFSET
}

/* ARGSUSED */
void
machtime_stream(s, sep)
	int s;
	struct servtab *sep;
{
	long result;

	result = machtime();
	(void) write(s, (char *) &result, sizeof(result));
}

/* ARGSUSED */
void
machtime_dg(s, sep)
	int s;
	struct servtab *sep;
{
	long result;
	struct sockaddr sa;
	int size;

	size = sizeof(sa);
	if (recvfrom(s, (char *)&result, sizeof(result), 0, &sa, &size) < 0)
		return;
	result = machtime();
	(void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
}

/* ARGSUSED */
void
daytime_stream(s, sep)		/* Return human-readable time of day */
	int s;
	struct servtab *sep;
{
	char buffer[256];
	time_t clock;

	clock = time((time_t *) 0);

	(void) sprintf(buffer, "%.24s\r\n", ctime(&clock));
	(void) write(s, buffer, strlen(buffer));
}

/* ARGSUSED */
void
daytime_dg(s, sep)		/* Return human-readable time of day */
	int s;
	struct servtab *sep;
{
	char buffer[256];
	time_t clock;
	struct sockaddr sa;
	int size;

	clock = time((time_t *) 0);

	size = sizeof(sa);
	if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
		return;
	(void) sprintf(buffer, "%.24s\r\n", ctime(&clock));
	(void) sendto(s, buffer, strlen(buffer), 0, &sa, sizeof(sa));
}

/*
 * print_service:
 *	Dump relevant information to stderr
 */
void
print_service(action, sep)
	char *action;
	struct servtab *sep;
{
	fprintf(stderr,
	    "%s: %s proto=%s, wait=%d, user=%s builtin=%x server=%s\n",
	    action, sep->se_service, sep->se_proto,
	    sep->se_wait, sep->se_user, (int)sep->se_bi, sep->se_server);
}

/*
 *  Based on TCPMUX.C by Mark K. Lottor November 1988
 *  sri-nic::ps:<mkl>tcpmux.c
 */


static int		/* # of characters upto \r,\n or \0 */
getline(fd, buf, len)
	int fd;
	char *buf;
	int len;
{
	int count = 0, n;

	do {
		n = read(fd, buf, len-count);
		if (n == 0)
			return (count);
		if (n < 0)
			return (-1);
		while (--n >= 0) {
			if (*buf == '\r' || *buf == '\n' || *buf == '\0')
				return (count);
			count++;
			buf++;
		}
	} while (count < len);
	return (count);
}

#define MAX_SERV_LEN	(256+2)		/* 2 bytes for \r\n */

#define strwrite(fd, buf)	(void) write(fd, buf, sizeof(buf)-1)

struct servtab *
tcpmux(s)
	int s;
{
	struct servtab *sep;
	char service[MAX_SERV_LEN+1];
	int len;

	/* Get requested service name */
	if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
		strwrite(s, "-Error reading service name\r\n");
		return (NULL);
	}
	service[len] = '\0';

	if (debug)
		fprintf(stderr, "tcpmux: someone wants %s\n", service);

	/*
	 * Help is a required command, and lists available services,
	 * one per line.
	 */
	if (!strcasecmp(service, "help")) {
		for (sep = servtab; sep; sep = sep->se_next) {
			if (!ISMUX(sep))
				continue;
			(void)write(s,sep->se_service,strlen(sep->se_service));
			strwrite(s, "\r\n");
		}
		return (NULL);
	}

	/* Try matching a service in inetd.conf with the request */
	for (sep = servtab; sep; sep = sep->se_next) {
		if (!ISMUX(sep))
			continue;
		if (!strcasecmp(service, sep->se_service)) {
			if (ISMUXPLUS(sep)) {
				strwrite(s, "+Go\r\n");
			}
			return (sep);
		}
	}
	strwrite(s, "-Service not available\r\n");
	return (NULL);
}