misc.c - security/openssh-library - Rivoreo Source Code Repositories

 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2005 Damien Miller.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "includes.h"
 RCSID("$OpenBSD: misc.c,v 1.31 2005/06/06 11:20:36 djm Exp $");

 #include "misc.h"
 #include "log.h"
 #include "xmalloc.h"

 /* remove newline at end of string */
 char *
 chop(char *s)
 {
 	char *t = s;
 	while (*t) {
 		if (*t == '\n' || *t == '\r') {
 			*t = '\0';
 			return s;
 		}
 		t++;
 	}
 	return s;

 }

 /* set/unset filedescriptor to non-blocking */
 int
 set_nonblock(int fd)
 {
 	int val;

 	val = fcntl(fd, F_GETFL, 0);
 	if (val < 0) {
 		error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
 		return (-1);
 	}
 	if (val & O_NONBLOCK) {
 		debug3("fd %d is O_NONBLOCK", fd);
 		return (0);
 	}
 	debug2("fd %d setting O_NONBLOCK", fd);
 	val |= O_NONBLOCK;
 	if (fcntl(fd, F_SETFL, val) == -1) {
 		debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
 		    strerror(errno));
 		return (-1);
 	}
 	return (0);
 }

 int
 unset_nonblock(int fd)
 {
 	int val;

 	val = fcntl(fd, F_GETFL, 0);
 	if (val < 0) {
 		error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
 		return (-1);
 	}
 	if (!(val & O_NONBLOCK)) {
 		debug3("fd %d is not O_NONBLOCK", fd);
 		return (0);
 	}
 	debug("fd %d clearing O_NONBLOCK", fd);
 	val &= ~O_NONBLOCK;
 	if (fcntl(fd, F_SETFL, val) == -1) {
 		debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
 		    fd, strerror(errno));
 		return (-1);
 	}
 	return (0);
 }

 /* disable nagle on socket */
 void
 set_nodelay(int fd)
 {
 	int opt;
 	socklen_t optlen;

 	optlen = sizeof opt;
 	if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
 		debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
 		return;
 	}
 	if (opt == 1) {
 		debug2("fd %d is TCP_NODELAY", fd);
 		return;
 	}
 	opt = 1;
 	debug2("fd %d setting TCP_NODELAY", fd);
 	if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
 		error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
 }

 /* Characters considered whitespace in strsep calls. */
 #define WHITESPACE " \t\r\n"

 /* return next token in configuration line */
 char *
 strdelim(char **s)
 {
 	char *old;
 	int wspace = 0;

 	if (*s == NULL)
 		return NULL;

 	old = *s;

 	*s = strpbrk(*s, WHITESPACE "=");
 	if (*s == NULL)
 		return (old);

 	/* Allow only one '=' to be skipped */
 	if (*s[0] == '=')
 		wspace = 1;
 	*s[0] = '\0';

 	*s += strspn(*s + 1, WHITESPACE) + 1;
 	if (*s[0] == '=' && !wspace)
 		*s += strspn(*s + 1, WHITESPACE) + 1;

 	return (old);
 }

 struct passwd *
 pwcopy(struct passwd *pw)
 {
 	struct passwd *copy = xmalloc(sizeof(*copy));

 	memset(copy, 0, sizeof(*copy));
 	copy->pw_name = xstrdup(pw->pw_name);
 	copy->pw_passwd = xstrdup(pw->pw_passwd);
 	copy->pw_gecos = xstrdup(pw->pw_gecos);
 	copy->pw_uid = pw->pw_uid;
 	copy->pw_gid = pw->pw_gid;
 #ifdef HAVE_PW_EXPIRE_IN_PASSWD
 	copy->pw_expire = pw->pw_expire;
 #endif
 #ifdef HAVE_PW_CHANGE_IN_PASSWD
 	copy->pw_change = pw->pw_change;
 #endif
 #ifdef HAVE_PW_CLASS_IN_PASSWD
 	copy->pw_class = xstrdup(pw->pw_class);
 #endif
 	copy->pw_dir = xstrdup(pw->pw_dir);
 	copy->pw_shell = xstrdup(pw->pw_shell);
 	return copy;
 }

 /*
  * Convert ASCII string to TCP/IP port number.
  * Port must be >0 and <=65535.
  * Return 0 if invalid.
  */
 int
 a2port(const char *s)
 {
 	long port;
 	char *endp;

 	errno = 0;
 	port = strtol(s, &endp, 0);
 	if (s == endp || *endp != '\0' ||
 	    (errno == ERANGE && (port == LONG_MIN || port == LONG_MAX)) ||
 	    port <= 0 || port > 65535)
 		return 0;

 	return port;
 }

 #define SECONDS		1
 #define MINUTES		(SECONDS * 60)
 #define HOURS		(MINUTES * 60)
 #define DAYS		(HOURS * 24)
 #define WEEKS		(DAYS * 7)

 /*
  * Convert a time string into seconds; format is
  * a sequence of:
  *      time[qualifier]
  *
  * Valid time qualifiers are:
  *      <none>  seconds
  *      s|S     seconds
  *      m|M     minutes
  *      h|H     hours
  *      d|D     days
  *      w|W     weeks
  *
  * Examples:
  *      90m     90 minutes
  *      1h30m   90 minutes
  *      2d      2 days
  *      1w      1 week
  *
  * Return -1 if time string is invalid.
  */
 long
 convtime(const char *s)
 {
 	long total, secs;
 	const char *p;
 	char *endp;

 	errno = 0;
 	total = 0;
 	p = s;

 	if (p == NULL || *p == '\0')
 		return -1;

 	while (*p) {
 		secs = strtol(p, &endp, 10);
 		if (p == endp ||
 		    (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
 		    secs < 0)
 			return -1;

 		switch (*endp++) {
 		case '\0':
 			endp--;
 		case 's':
 		case 'S':
 			break;
 		case 'm':
 		case 'M':
 			secs *= MINUTES;
 			break;
 		case 'h':
 		case 'H':
 			secs *= HOURS;
 			break;
 		case 'd':
 		case 'D':
 			secs *= DAYS;
 			break;
 		case 'w':
 		case 'W':
 			secs *= WEEKS;
 			break;
 		default:
 			return -1;
 		}
 		total += secs;
 		if (total < 0)
 			return -1;
 		p = endp;
 	}

 	return total;
 }

 /*
  * Search for next delimiter between hostnames/addresses and ports.
  * Argument may be modified (for termination).
  * Returns *cp if parsing succeeds.
  * *cp is set to the start of the next delimiter, if one was found.
  * If this is the last field, *cp is set to NULL.
  */
 char *
 hpdelim(char **cp)
 {
 	char *s, *old;

 	if (cp == NULL || *cp == NULL)
 		return NULL;

 	old = s = *cp;
 	if (*s == '[') {
 		if ((s = strchr(s, ']')) == NULL)
 			return NULL;
 		else
 			s++;
 	} else if ((s = strpbrk(s, ":/")) == NULL)
 		s = *cp + strlen(*cp); /* skip to end (see first case below) */

 	switch (*s) {
 	case '\0':
 		*cp = NULL;	/* no more fields*/
 		break;

 	case ':':
 	case '/':
 		*s = '\0';	/* terminate */
 		*cp = s + 1;
 		break;

 	default:
 		return NULL;
 	}

 	return old;
 }

 char *
 cleanhostname(char *host)
 {
 	if (*host == '[' && host[strlen(host) - 1] == ']') {
 		host[strlen(host) - 1] = '\0';
 		return (host + 1);
 	} else
 		return host;
 }

 char *
 colon(char *cp)
 {
 	int flag = 0;

 	if (*cp == ':')		/* Leading colon is part of file name. */
 		return (0);
 	if (*cp == '[')
 		flag = 1;

 	for (; *cp; ++cp) {
 		if (*cp == '@' && *(cp+1) == '[')
 			flag = 1;
 		if (*cp == ']' && *(cp+1) == ':' && flag)
 			return (cp+1);
 		if (*cp == ':' && !flag)
 			return (cp);
 		if (*cp == '/')
 			return (0);
 	}
 	return (0);
 }

 /* function to assist building execv() arguments */
 void
 addargs(arglist *args, char *fmt, ...)
 {
 	va_list ap;
 	char buf[1024];
 	u_int nalloc;

 	va_start(ap, fmt);
 	vsnprintf(buf, sizeof(buf), fmt, ap);
 	va_end(ap);

 	nalloc = args->nalloc;
 	if (args->list == NULL) {
 		nalloc = 32;
 		args->num = 0;
 	} else if (args->num+2 >= nalloc)
 		nalloc *= 2;

 	args->list = xrealloc(args->list, nalloc * sizeof(char *));
 	args->nalloc = nalloc;
 	args->list[args->num++] = xstrdup(buf);
 	args->list[args->num] = NULL;
 }

 /*
  * Expands tildes in the file name.  Returns data allocated by xmalloc.
  * Warning: this calls getpw*.
  */
 char *
 tilde_expand_filename(const char *filename, uid_t uid)
 {
 	const char *path;
 	char user[128], ret[MAXPATHLEN];
 	struct passwd *pw;
 	int len;

 	if (*filename != '~')
 		return (xstrdup(filename));
 	filename++;

 	path = strchr(filename, '/');
 	if (path != NULL && path > filename) {		/* ~user/path */
 		if (path - filename > sizeof(user) - 1)
 			fatal("tilde_expand_filename: ~username too long");
 		memcpy(user, filename, path - filename);
 		user[path - filename] = '\0';
 		if ((pw = getpwnam(user)) == NULL)
 			fatal("tilde_expand_filename: No such user %s", user);
 	} else if ((pw = getpwuid(uid)) == NULL)	/* ~/path */
 		fatal("tilde_expand_filename: No such uid %d", uid);

 	if (strlcpy(ret, pw->pw_dir, sizeof(ret)) >= sizeof(ret))
 		fatal("tilde_expand_filename: Path too long");

 	/* Make sure directory has a trailing '/' */
 	len = strlen(pw->pw_dir);
 	if ((len == 0 || pw->pw_dir[len - 1] != '/') &&
 	    strlcat(ret, "/", sizeof(ret)) >= sizeof(ret))
 		fatal("tilde_expand_filename: Path too long");

 	/* Skip leading '/' from specified path */
 	if (path != NULL)
 		filename = path + 1;
 	if (strlcat(ret, filename, sizeof(ret)) >= sizeof(ret))
 		fatal("tilde_expand_filename: Path too long");

 	return (xstrdup(ret));
 }

 /*
  * Expand a string with a set of %[char] escapes. A number of escapes may be
  * specified as (char *escape_chars, char *replacement) pairs. The list must
  * be terminated by an escape_char of -1. Returns replaced string in memory
  * allocated by xmalloc.
  */
 char *
 percent_expand(const char *string, ...)
 {
 #define EXPAND_MAX_KEYS	16
 	struct {
 		const char *key;
 		const char *repl;
 	} keys[EXPAND_MAX_KEYS];
 	int num_keys, i, j;
 	char buf[4096];
 	va_list ap;

 	/* Gather keys */
 	va_start(ap, string);
 	for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
 		keys[num_keys].key = va_arg(ap, char *);
 		if (keys[num_keys].key == NULL)
 			break;
 		keys[num_keys].repl = va_arg(ap, char *);
 		if (keys[num_keys].repl == NULL)
 			fatal("percent_expand: NULL replacement");
 	}
 	va_end(ap);

 	if (num_keys >= EXPAND_MAX_KEYS)
 		fatal("percent_expand: too many keys");

 	/* Expand string */
 	*buf = '\0';
 	for (i = 0; *string != '\0'; string++) {
 		if (*string != '%') {
  append:
 			buf[i++] = *string;
 			if (i >= sizeof(buf))
 				fatal("percent_expand: string too long");
 			buf[i] = '\0';
 			continue;
 		}
 		string++;
 		if (*string == '%')
 			goto append;
 		for (j = 0; j < num_keys; j++) {
 			if (strchr(keys[j].key, *string) != NULL) {
 				i = strlcat(buf, keys[j].repl, sizeof(buf));
 				if (i >= sizeof(buf))
 					fatal("percent_expand: string too long");
 				break;
 			}
 		}
 		if (j >= num_keys)
 			fatal("percent_expand: unknown key %%%c", *string);
 	}
 	return (xstrdup(buf));
 #undef EXPAND_MAX_KEYS
 }

 /*
  * Read an entire line from a public key file into a static buffer, discarding
  * lines that exceed the buffer size.  Returns 0 on success, -1 on failure.
  */
 int
 read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
    u_long *lineno)
 {
 	while (fgets(buf, bufsz, f) != NULL) {
 		(*lineno)++;
 		if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
 			return 0;
 		} else {
 			debug("%s: %s line %lu exceeds size limit", __func__,
 			    filename, *lineno);
 			/* discard remainder of line */
 			while (fgetc(f) != '\n' && !feof(f))
 				;	/* nothing */
 		}
 	}
 	return -1;
 }
	/*
	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	* Copyright (c) 2005 Damien Miller. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "includes.h"
	RCSID("$OpenBSD: misc.c,v 1.31 2005/06/06 11:20:36 djm Exp $");

	#include "misc.h"
	#include "log.h"
	#include "xmalloc.h"

	/* remove newline at end of string */
	char *
	chop(char *s)
	{
	char *t = s;
	while (*t) {
	if (t == '\n' \|\| t == '\r') {
	*t = '\0';
	return s;
	}
	t++;
	}
	return s;

	}

	/* set/unset filedescriptor to non-blocking */
	int
	set_nonblock(int fd)
	{
	int val;

	val = fcntl(fd, F_GETFL, 0);
	if (val < 0) {
	error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
	return (-1);
	}
	if (val & O_NONBLOCK) {
	debug3("fd %d is O_NONBLOCK", fd);
	return (0);
	}
	debug2("fd %d setting O_NONBLOCK", fd);
	val \|= O_NONBLOCK;
	if (fcntl(fd, F_SETFL, val) == -1) {
	debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
	strerror(errno));
	return (-1);
	}
	return (0);
	}

	int
	unset_nonblock(int fd)
	{
	int val;

	val = fcntl(fd, F_GETFL, 0);
	if (val < 0) {
	error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
	return (-1);
	}
	if (!(val & O_NONBLOCK)) {
	debug3("fd %d is not O_NONBLOCK", fd);
	return (0);
	}
	debug("fd %d clearing O_NONBLOCK", fd);
	val &= ~O_NONBLOCK;
	if (fcntl(fd, F_SETFL, val) == -1) {
	debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
	fd, strerror(errno));
	return (-1);
	}
	return (0);
	}

	/* disable nagle on socket */
	void
	set_nodelay(int fd)
	{
	int opt;
	socklen_t optlen;

	optlen = sizeof opt;
	if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
	debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
	return;
	}
	if (opt == 1) {
	debug2("fd %d is TCP_NODELAY", fd);
	return;
	}
	opt = 1;
	debug2("fd %d setting TCP_NODELAY", fd);
	if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
	error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
	}

	/* Characters considered whitespace in strsep calls. */
	#define WHITESPACE " \t\r\n"

	/* return next token in configuration line */
	char *
	strdelim(char **s)
	{
	char *old;
	int wspace = 0;

	if (*s == NULL)
	return NULL;

	old = *s;

	s = strpbrk(s, WHITESPACE "=");
	if (*s == NULL)
	return (old);

	/* Allow only one '=' to be skipped */
	if (*s[0] == '=')
	wspace = 1;
	*s[0] = '\0';

	s += strspn(s + 1, WHITESPACE) + 1;
	if (*s[0] == '=' && !wspace)
	s += strspn(s + 1, WHITESPACE) + 1;

	return (old);
	}

	struct passwd *
	pwcopy(struct passwd *pw)
	{
	struct passwd copy = xmalloc(sizeof(copy));

	memset(copy, 0, sizeof(*copy));
	copy->pw_name = xstrdup(pw->pw_name);
	copy->pw_passwd = xstrdup(pw->pw_passwd);
	copy->pw_gecos = xstrdup(pw->pw_gecos);
	copy->pw_uid = pw->pw_uid;
	copy->pw_gid = pw->pw_gid;
	#ifdef HAVE_PW_EXPIRE_IN_PASSWD
	copy->pw_expire = pw->pw_expire;
	#endif
	#ifdef HAVE_PW_CHANGE_IN_PASSWD
	copy->pw_change = pw->pw_change;
	#endif
	#ifdef HAVE_PW_CLASS_IN_PASSWD
	copy->pw_class = xstrdup(pw->pw_class);
	#endif
	copy->pw_dir = xstrdup(pw->pw_dir);
	copy->pw_shell = xstrdup(pw->pw_shell);
	return copy;
	}

	/*
	* Convert ASCII string to TCP/IP port number.
	* Port must be >0 and <=65535.
	* Return 0 if invalid.
	*/
	int
	a2port(const char *s)
	{
	long port;
	char *endp;

	errno = 0;
	port = strtol(s, &endp, 0);
	if (s == endp \|\| *endp != '\0' \|\|
	(errno == ERANGE && (port == LONG_MIN \|\| port == LONG_MAX)) \|\|
	port <= 0 \|\| port > 65535)
	return 0;

	return port;
	}

	#define SECONDS 1
	#define MINUTES (SECONDS * 60)
	#define HOURS (MINUTES * 60)
	#define DAYS (HOURS * 24)
	#define WEEKS (DAYS * 7)

	/*
	* Convert a time string into seconds; format is
	* a sequence of:
	* time[qualifier]
	*
	* Valid time qualifiers are:
	* <none> seconds
	* s\|S seconds
	* m\|M minutes
	* h\|H hours
	* d\|D days
	* w\|W weeks
	*
	* Examples:
	* 90m 90 minutes
	* 1h30m 90 minutes
	* 2d 2 days
	* 1w 1 week
	*
	* Return -1 if time string is invalid.
	*/
	long
	convtime(const char *s)
	{
	long total, secs;
	const char *p;
	char *endp;

	errno = 0;
	total = 0;
	p = s;

	if (p == NULL \|\| *p == '\0')
	return -1;

	while (*p) {
	secs = strtol(p, &endp, 10);
	if (p == endp \|\|
	(errno == ERANGE && (secs == LONG_MIN \|\| secs == LONG_MAX)) \|\|
	secs < 0)
	return -1;

	switch (*endp++) {
	case '\0':
	endp--;
	case 's':
	case 'S':
	break;
	case 'm':
	case 'M':
	secs *= MINUTES;
	break;
	case 'h':
	case 'H':
	secs *= HOURS;
	break;
	case 'd':
	case 'D':
	secs *= DAYS;
	break;
	case 'w':
	case 'W':
	secs *= WEEKS;
	break;
	default:
	return -1;
	}
	total += secs;
	if (total < 0)
	return -1;
	p = endp;
	}

	return total;
	}

	/*
	* Search for next delimiter between hostnames/addresses and ports.
	* Argument may be modified (for termination).
	* Returns *cp if parsing succeeds.
	* *cp is set to the start of the next delimiter, if one was found.
	* If this is the last field, *cp is set to NULL.
	*/
	char *
	hpdelim(char **cp)
	{
	char s, old;

	if (cp == NULL \|\| *cp == NULL)
	return NULL;

	old = s = *cp;
	if (*s == '[') {
	if ((s = strchr(s, ']')) == NULL)
	return NULL;
	else
	s++;
	} else if ((s = strpbrk(s, ":/")) == NULL)
	s = cp + strlen(cp); /* skip to end (see first case below) */

	switch (*s) {
	case '\0':
	cp = NULL; / no more fields*/
	break;

	case ':':
	case '/':
	s = '\0'; / terminate */
	*cp = s + 1;
	break;

	default:
	return NULL;
	}

	return old;
	}

	char *
	cleanhostname(char *host)
	{
	if (*host == '[' && host[strlen(host) - 1] == ']') {
	host[strlen(host) - 1] = '\0';
	return (host + 1);
	} else
	return host;
	}

	char *
	colon(char *cp)
	{
	int flag = 0;

	if (cp == ':') / Leading colon is part of file name. */
	return (0);
	if (*cp == '[')
	flag = 1;

	for (; *cp; ++cp) {
	if (cp == '@' && (cp+1) == '[')
	flag = 1;
	if (cp == ']' && (cp+1) == ':' && flag)
	return (cp+1);
	if (*cp == ':' && !flag)
	return (cp);
	if (*cp == '/')
	return (0);
	}
	return (0);
	}

	/* function to assist building execv() arguments */
	void
	addargs(arglist args, char fmt, ...)
	{
	va_list ap;
	char buf[1024];
	u_int nalloc;

	va_start(ap, fmt);
	vsnprintf(buf, sizeof(buf), fmt, ap);
	va_end(ap);

	nalloc = args->nalloc;
	if (args->list == NULL) {
	nalloc = 32;
	args->num = 0;
	} else if (args->num+2 >= nalloc)
	nalloc *= 2;

	args->list = xrealloc(args->list, nalloc * sizeof(char *));
	args->nalloc = nalloc;
	args->list[args->num++] = xstrdup(buf);
	args->list[args->num] = NULL;
	}

	/*
	* Expands tildes in the file name. Returns data allocated by xmalloc.
	* Warning: this calls getpw*.
	*/
	char *
	tilde_expand_filename(const char *filename, uid_t uid)
	{
	const char *path;
	char user[128], ret[MAXPATHLEN];
	struct passwd *pw;
	int len;

	if (*filename != '~')
	return (xstrdup(filename));
	filename++;

	path = strchr(filename, '/');
	if (path != NULL && path > filename) { /* ~user/path */
	if (path - filename > sizeof(user) - 1)
	fatal("tilde_expand_filename: ~username too long");
	memcpy(user, filename, path - filename);
	user[path - filename] = '\0';
	if ((pw = getpwnam(user)) == NULL)
	fatal("tilde_expand_filename: No such user %s", user);
	} else if ((pw = getpwuid(uid)) == NULL) /* ~/path */
	fatal("tilde_expand_filename: No such uid %d", uid);

	if (strlcpy(ret, pw->pw_dir, sizeof(ret)) >= sizeof(ret))
	fatal("tilde_expand_filename: Path too long");

	/* Make sure directory has a trailing '/' */
	len = strlen(pw->pw_dir);
	if ((len == 0 \|\| pw->pw_dir[len - 1] != '/') &&
	strlcat(ret, "/", sizeof(ret)) >= sizeof(ret))
	fatal("tilde_expand_filename: Path too long");

	/* Skip leading '/' from specified path */
	if (path != NULL)
	filename = path + 1;
	if (strlcat(ret, filename, sizeof(ret)) >= sizeof(ret))
	fatal("tilde_expand_filename: Path too long");

	return (xstrdup(ret));
	}

	/*
	* Expand a string with a set of %[char] escapes. A number of escapes may be
	* specified as (char escape_chars, char replacement) pairs. The list must
	* be terminated by an escape_char of -1. Returns replaced string in memory
	* allocated by xmalloc.
	*/
	char *
	percent_expand(const char *string, ...)
	{
	#define EXPAND_MAX_KEYS 16
	struct {
	const char *key;
	const char *repl;
	} keys[EXPAND_MAX_KEYS];
	int num_keys, i, j;
	char buf[4096];
	va_list ap;

	/* Gather keys */
	va_start(ap, string);
	for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
	keys[num_keys].key = va_arg(ap, char *);
	if (keys[num_keys].key == NULL)
	break;
	keys[num_keys].repl = va_arg(ap, char *);
	if (keys[num_keys].repl == NULL)
	fatal("percent_expand: NULL replacement");
	}
	va_end(ap);

	if (num_keys >= EXPAND_MAX_KEYS)
	fatal("percent_expand: too many keys");

	/* Expand string */
	*buf = '\0';
	for (i = 0; *string != '\0'; string++) {
	if (*string != '%') {
	append:
	buf[i++] = *string;
	if (i >= sizeof(buf))
	fatal("percent_expand: string too long");
	buf[i] = '\0';
	continue;
	}
	string++;
	if (*string == '%')
	goto append;
	for (j = 0; j < num_keys; j++) {
	if (strchr(keys[j].key, *string) != NULL) {
	i = strlcat(buf, keys[j].repl, sizeof(buf));
	if (i >= sizeof(buf))
	fatal("percent_expand: string too long");
	break;
	}
	}
	if (j >= num_keys)
	fatal("percent_expand: unknown key %%%c", *string);
	}
	return (xstrdup(buf));
	#undef EXPAND_MAX_KEYS
	}

	/*
	* Read an entire line from a public key file into a static buffer, discarding
	* lines that exceed the buffer size. Returns 0 on success, -1 on failure.
	*/
	int
	read_keyfile_line(FILE f, const char filename, char *buf, size_t bufsz,
	u_long *lineno)
	{
	while (fgets(buf, bufsz, f) != NULL) {
	(*lineno)++;
	if (buf[strlen(buf) - 1] == '\n' \|\| feof(f)) {
	return 0;
	} else {
	debug("%s: %s line %lu exceeds size limit", __func__,
	filename, *lineno);
	/* discard remainder of line */
	while (fgetc(f) != '\n' && !feof(f))
	; /* nothing */
	}
	}
	return -1;
	}