[unix-history] / usr / src / cmd / delivermail / conf.c

# include <stdio.h>
# include <pwd.h>
# include "dlvrmail.h"

/*
**  CONF.C -- Delivermail Configuration Tables.
**
**	Defines the configuration of this installation.
**
**	Compilation Flags:
**		HASARPA -- set if this machine has a connection to
**			the Arpanet.
**		HASUUCP -- set if this machine has a connection to
**			the UUCP network.
**		NETV6MAIL -- set if you want to use "v6mail" that
**			comes with the Berkeley network.  Normally
**			/bin/mail will work fine, but around Berkeley
**			we use v6mail because it is a "fixed target".
**		V6 -- running on a version 6 system.  This determines
**			whether to define certain routines between
**			the two systems.  If you are running a funny
**			system, e.g., V6 with long tty names, this
**			should be checked carefully.
**		DUMBMAIL -- set if your /bin/mail doesn't have the
**			-d flag.
**
**	Configuration Variables:
**		ArpaHost -- the arpanet name of the host through
**			which arpanet mail will be sent.
**		MyLocName -- the name of the host on a local network.
**			This is used to disambiguate the contents of
**			ArpaHost among many hosts who may be sharing
**			a gateway.
**		ArpaLocal -- a list of local names for this host on
**			the arpanet.  Only functional if HASARPA set.
**		UucpLocal -- ditto for the Arpanet.
**		BerkLocal -- ditto for the Berknet.
**		Mailer -- a table of mailers known to the system.
**			The fields are:
**			- the pathname of the mailer.
**			- a list of flags describing the properties
**			  of this mailer:
**			   M_FOPT -- if set, the mailer has a picky "-f"
**				option.  In this mode, the mailer will
**				only accept the "-f" option if the
**				sender is actually "root", "network",
**				and possibly (but not necessarily) if
**				the -f argument matches the real sender.
**				The effect is that if the "-f" option
**				is given to delivermail then it will be
**				passed through (as arguments 1 & 2) to
**				the mailer.
**			   M_ROPT -- identical to M_FOPT, except uses
**				-r instead.
**			   M_QUIET -- if set, don't print a message if
**				the mailer returns bad status.
**			   M_RESTR -- if set, this mailer is restricted
**				to use by "daemon"; otherwise, we do a
**				setuid(getuid()) before calling the
**				mailer.
**			   M_HDR -- if set, the mailer wants us to
**				insert a UNIX "From" line before
**				outputing.
**			   M_NOHOST -- if set, this mailer doesn't care
**				about the host part (e.g., the local
**				mailer).
**			   M_STRIPQ -- if set, strip quote (`"')
**				characters out of parameters as you
**				transliterate them into the argument
**				vector.  For example, the local mailer
**				is called directly, so these should be
**				stripped, but the program-mailer (i.e.,
**				csh) should leave them in.
**			- an exit status to use as the code for the
**			  error message print if the mailer returns
**			  something we don't understand.
**			- A list of names that are to be considered
**			  "local" (and hence are stripped off) for
**			  this mailer.
**			- An argument vector to be passed to the
**			  mailer with the following substitutions:
**			   $f - the from person name.
**			   $u - the target user name.
**			   $h - the target user host.
**			   $c - the hop count.
**			>>>>>>>>>> Entry zero must be for the local
**			>> NOTE >> mailer and entry one must be for
**			>>>>>>>>>> the shell.
**		ParseTab -- a table driving the parsing process.  Each
**			entry contains:
**			- a character that will trigger this entry.
**			- an index into the Mailer table.
**			- a word of flags, described in dlvrmail.h.
**			- an argument.  If we have P_MAP, it is the
**			  character to turn the trigger character into.
**			  If we have P_MOVE, it is the site to send it
**			  to, using the mailer specified above.
**			This table will almost certainly have to be
**			changed on your site if you have anything more
**			than the UUCP net.
*/


static char SccsId[] = "@(#)conf.c	1.10	10/21/80";

/************ BEGIN CONFIGURATION SECTION ************/

bool	UseMsgId = FALSE;	/* don't put message id's in anywhere */

# include <whoami.h>		/* definitions of machine id's at berkeley */

char	*ArpaHost = "[unknown]";
char	*MyLocName = sysname;
# define HASUUCP		/* default to having UUCP net */
char	*UucpLocal[] = { sysname, NULL };
/* if you define HASARPA you must include a declaration for ArpaLocal */

/************ END CONFIGURATION SECTION ************/

# ifndef HASARPA
# define ArpaLocal	NULL
# endif HASARPA

# ifndef HASUUCP
# define UucpLocal	NULL
# endif HASUUCP

# ifndef HASBERK
# define BerkLocal	NULL
# endif HASBERK


struct mailer Mailer[] =
{
	/* local mail -- must be #0 */
	{
# ifdef NETV6MAIL
		"/usr/net/bin/v6mail",
# else
		"/bin/mail",
# endif
		M_ROPT|M_NOHOST|M_STRIPQ,	EX_NOUSER,	NULL,
		{ "...local%mail", "-d", "$u", NULL }
	},
	/* pipes through programs -- must be #1 */
	{
		"/bin/csh",
		M_HDR|M_NOHOST,			EX_UNAVAILABLE,	NULL,
		{ "...prog%mail", "-fc", "$u", NULL }
	},
	/* local berkeley mail */
	{
		"/usr/net/bin/sendberkmail",
		M_FOPT|M_HDR|M_STRIPQ,		EX_UNAVAILABLE,	BerkLocal,
		{ "...berk%mail", "-m", "$h", "-t", "$u", "-h", "$c", NULL }
	},
	/* arpanet mail */
	{
		"/usr/lib/mailers/arpa",
		M_STRIPQ,			0,		ArpaLocal,
		{ "...arpa%mail", "$f", "$h", "$u", NULL }
	},
	/* uucp mail (cheat & use Bell's v7 mail) */
	{
		"/bin/mail",
		M_ROPT|M_STRIPQ,		EX_NOUSER,	UucpLocal,
# ifdef DUMBMAIL
		{ "...uucp%mail", "$h!$u", NULL }
# else
		{ "...uucp%mail", "-d", "$h!$u", NULL }
# endif DUMBMAIL
	},
};

# define M_LOCAL	0
# define M_BERK		2
# define M_ARPA		3
# define M_UUCP		4


struct parsetab ParseTab[] =
{
# ifdef HASARPA
	'@',	M_ARPA,		P_HLAST|P_USR_UPPER,		NULL,
# endif HASARPA
# ifdef HASUUCP
	'^',	-1,		P_MAP,				"!",
	'!',	M_UUCP,		0,				NULL,
# endif HASUUCP
	'\0',	M_LOCAL,	P_MOVE,				"",
};
\f/*
**  GETNAME -- Get the current users login name.
**
**	This is in config.c because it is somewhat machine dependent.
**	Examine it carefully for your installation.
**
**	Algorithm:
**		See if the person is logged in.  If so, return
**			the name s/he is logged in as.
**		Look up the user id in /etc/passwd.  If found,
**			return that name.
**		Return NULL.
**
**	Parameters:
**		none
**
**	Returns:
**		The login name of this user.
**		NULL if this person is noone.
**
**	Side Effects:
**		none
**
**	Called By:
**		main
*/

char *
getname()
{
	register char *p;
	register struct passwd *w;
	extern char *getlogin();
	extern struct passwd *getpwuid();
	static char namebuf[9];

	p = getlogin();
	if (p != NULL && p[0] != '\0')
		return (p);
# ifdef V6
	w = getpwuid(getuid() & 0377);
# else
	w = getpwuid(getuid());
# endif V6
	if (w != NULL)
	{
		strcpy(namebuf, w->pw_name);
		return (namebuf);
	}
	return (NULL);
}
\f
# ifdef V6
/*
**  TTYPATH -- Get the path of the user's tty -- Version 6 version.
**
**	Returns the pathname of the user's tty.  Returns NULL if
**	the user is not logged in or if s/he has write permission
**	denied.
**
**	Parameters:
**		none
**
**	Returns:
**		pathname of the user's tty.
**		NULL if not logged in or write permission denied.
**
**	Side Effects:
**		none.
**
**	WARNING:
**		Return value is in a local buffer.
**
**	Called By:
**		savemail
*/

# include <sys/types.h>
# include <sys/stat.h>

char *
ttypath()
{
	struct stat stbuf;
	register int i;
	static char pathn[] = "/dev/ttyx";
	extern int errno;

	/* compute the pathname of the controlling tty */
	if ((i = ttyn(2)) == 'x' && (i = ttyn(1)) == 'x' && (i = ttyn(0)) == 'x')
	{
		errno = 0;
		return (NULL);
	}
	pathn[8] = i;

	/* see if we have write permission */
	if (stat(pathn, &stbuf) < 0 || !flagset(02, stbuf.st_mode))
	{
		errno = 0;
		return (NULL);
	}

	/* see if the user is logged in */
	if (getlogin() == NULL)
		return (NULL);

	/* looks good */
	return (pathn);
}
\f/*
**  FDOPEN -- Open a stdio file given an open file descriptor.
**
**	This is included here because it is standard in v7, but we
**	need it in v6.
**
**	Algorithm:
**		Open /dev/null to create a descriptor.
**		Close that descriptor.
**		Copy the existing fd into the descriptor.
**
**	Parameters:
**		fd -- the open file descriptor.
**		type -- "r", "w", or whatever.
**
**	Returns:
**		The file descriptor it creates.
**
**	Side Effects:
**		none
**
**	Called By:
**		deliver
**
**	Notes:
**		The mode of fd must match "type".
*/

FILE *
fdopen(fd, type)
	int fd;
	char *type;
{
	register FILE *f;

	f = fopen("/dev/null", type);
	close(fileno(f));
	fileno(f) = fd;
	return (f);
}
\f/*
**  INDEX -- Return pointer to character in string
**
**	For V7 compatibility.
**
**	Parameters:
**		s -- a string to scan.
**		c -- a character to look for.
**
**	Returns:
**		If c is in s, returns the address of the first
**			instance of c in s.
**		NULL if c is not in s.
**
**	Side Effects:
**		none.
*/

index(s, c)
	register char *s;
	register char c;
{
	while (*s != '\0')
	{
		if (*s++ == c)
			return (--s);
	}
	return (NULL);
}
# endif V6
\f
# ifndef V6
/*
**  TTYPATH -- Get the path of the user's tty -- Version 7 version.
**
**	Returns the pathname of the user's tty.  Returns NULL if
**	the user is not logged in or if s/he has write permission
**	denied.
**
**	Parameters:
**		none
**
**	Returns:
**		pathname of the user's tty.
**		NULL if not logged in or write permission denied.
**
**	Side Effects:
**		none.
**
**	WARNING:
**		Return value is in a local buffer.
**
**	Called By:
**		savemail
*/

# include <sys/types.h>
# include <sys/stat.h>

char *
ttypath()
{
	struct stat stbuf;
	register char *pathn;
	extern int errno;
	extern char *ttyname();

	/* compute the pathname of the controlling tty */
	if ((pathn = ttyname(2)) == NULL && (pathn = ttyname(1)) == NULL && (pathn = ttyname(0)) == NULL)
	{
		errno = 0;
		return (NULL);
	}

	/* see if we have write permission */
	if (stat(pathn, &stbuf) < 0 || !flagset(02, stbuf.st_mode))
	{
		errno = 0;
		return (NULL);
	}

	/* see if the user is logged in */
	if (getlogin() == NULL)
		return (NULL);

	/* looks good */
	return (pathn);
}
# endif V6
Commit	Line	Data
b3cbe40f EA	1	# include <stdio.h>
	2	# include <pwd.h>
	3	# include "dlvrmail.h"
916b3375	4
b3cbe40f EA	5	/*
	6	** CONF.C -- Delivermail Configuration Tables.
	7	**
	8	** Defines the configuration of this installation.
	9	**
cb590f52 EA	10	** Compilation Flags:
	11	** HASARPA -- set if this machine has a connection to
	12	** the Arpanet.
	13	** HASUUCP -- set if this machine has a connection to
	14	** the UUCP network.
	15	** NETV6MAIL -- set if you want to use "v6mail" that
	16	** comes with the Berkeley network. Normally
	17	** /bin/mail will work fine, but around Berkeley
	18	** we use v6mail because it is a "fixed target".
	19	** V6 -- running on a version 6 system. This determines
	20	** whether to define certain routines between
	21	** the two systems. If you are running a funny
	22	** system, e.g., V6 with long tty names, this
	23	** should be checked carefully.
849eaf63 EA	24	** DUMBMAIL -- set if your /bin/mail doesn't have the
849eaf63 EA	25	** -d flag.
b3cbe40f	26	**
cb590f52	27	** Configuration Variables:
849eaf63 EA	28	** ArpaHost -- the arpanet name of the host through
849eaf63 EA	29	** which arpanet mail will be sent.
cb590f52 EA	30	** MyLocName -- the name of the host on a local network.
	31	** This is used to disambiguate the contents of
	32	** ArpaHost among many hosts who may be sharing
	33	** a gateway.
849eaf63 EA	34	** ArpaLocal -- a list of local names for this host on
	35	** the arpanet. Only functional if HASARPA set.
	36	** UucpLocal -- ditto for the Arpanet.
	37	** BerkLocal -- ditto for the Berknet.
cb590f52 EA	38	** Mailer -- a table of mailers known to the system.
	39	** The fields are:
	40	** - the pathname of the mailer.
	41	** - a list of flags describing the properties
	42	** of this mailer:
	43	** M_FOPT -- if set, the mailer has a picky "-f"
	44	** option. In this mode, the mailer will
	45	** only accept the "-f" option if the
	46	** sender is actually "root", "network",
	47	** and possibly (but not necessarily) if
	48	** the -f argument matches the real sender.
	49	** The effect is that if the "-f" option
	50	** is given to delivermail then it will be
	51	** passed through (as arguments 1 & 2) to
	52	** the mailer.
	53	** M_ROPT -- identical to M_FOPT, except uses
	54	** -r instead.
	55	** M_QUIET -- if set, don't print a message if
	56	** the mailer returns bad status.
	57	** M_RESTR -- if set, this mailer is restricted
	58	** to use by "daemon"; otherwise, we do a
	59	** setuid(getuid()) before calling the
	60	** mailer.
	61	** M_HDR -- if set, the mailer wants us to
	62	** insert a UNIX "From" line before
	63	** outputing.
	64	** M_NOHOST -- if set, this mailer doesn't care
	65	** about the host part (e.g., the local
	66	** mailer).
	67	** M_STRIPQ -- if set, strip quote (`"')
	68	** characters out of parameters as you
	69	** transliterate them into the argument
	70	** vector. For example, the local mailer
	71	** is called directly, so these should be
	72	** stripped, but the program-mailer (i.e.,
	73	** csh) should leave them in.
	74	** - an exit status to use as the code for the
	75	** error message print if the mailer returns
	76	** something we don't understand.
	77	** - A list of names that are to be considered
	78	** "local" (and hence are stripped off) for
	79	** this mailer.
	80	** - An argument vector to be passed to the
	81	** mailer with the following substitutions:
	82	** $f - the from person name.
	83	** $u - the target user name.
	84	** $h - the target user host.
	85	** $c - the hop count.
	86	** >>>>>>>>>> Entry zero must be for the local
	87	** >> NOTE >> mailer and entry one must be for
	88	** >>>>>>>>>> the shell.
	89	** ParseTab -- a table driving the parsing process. Each
	90	** entry contains:
	91	** - a character that will trigger this entry.
	92	** - an index into the Mailer table.
	93	** - a word of flags, described in dlvrmail.h.
	94	** - an argument. If we have P_MAP, it is the
	95	** character to turn the trigger character into.
	96	** If we have P_MOVE, it is the site to send it
	97	** to, using the mailer specified above.
849eaf63 EA	98	** This table will almost certainly have to be
	99	** changed on your site if you have anything more
	100	** than the UUCP net.
b3cbe40f EA	101	*/
	102
	103
	104
	105
31cef89c	106	static char SccsId[] = "@(#)conf.c 1.10 10/21/80";
cb590f52	107
31cef89c	108	/********** BEGIN CONFIGURATION SECTION **********/
cb590f52	109
cb590f52 EA	110	bool UseMsgId = FALSE; /* don't put message id's in anywhere */
	111
	112	# include <whoami.h> /* definitions of machine id's at berkeley */
b3cbe40f	113
849eaf63 EA	114	char *ArpaHost = "[unknown]";
	115	char *MyLocName = sysname;
	116	# define HASUUCP /* default to having UUCP net */
	117	char *UucpLocal[] = { sysname, NULL };
31cef89c	118	/* if you define HASARPA you must include a declaration for ArpaLocal */
b3cbe40f	119
31cef89c	120	/********** END CONFIGURATION SECTION **********/
50e67097 EA	121
	122	# ifndef HASARPA
	123	# define ArpaLocal NULL
	124	# endif HASARPA
	125
	126	# ifndef HASUUCP
	127	# define UucpLocal NULL
	128	# endif HASUUCP
	129
31cef89c BJ	130	# ifndef HASBERK
	131	# define BerkLocal NULL
	132	# endif HASBERK
	133
50e67097	134
b3cbe40f EA	135	struct mailer Mailer[] =
	136	{
	137	/* local mail -- must be #0 */
	138	{
	139	# ifdef NETV6MAIL
	140	"/usr/net/bin/v6mail",
	141	# else
	142	"/bin/mail",
	143	# endif
	144	M_ROPT\|M_NOHOST\|M_STRIPQ, EX_NOUSER, NULL,
	145	{ "...local%mail", "-d", "$u", NULL }
	146	},
	147	/* pipes through programs -- must be #1 */
	148	{
	149	"/bin/csh",
21ec078e	150	M_HDR\|M_NOHOST, EX_UNAVAILABLE, NULL,
b3cbe40f EA	151	{ "...prog%mail", "-fc", "$u", NULL }
	152	},
	153	/* local berkeley mail */
	154	{
	155	"/usr/net/bin/sendberkmail",
21ec078e	156	M_FOPT\|M_HDR\|M_STRIPQ, EX_UNAVAILABLE, BerkLocal,
b3cbe40f EA	157	{ "...berk%mail", "-m", "$h", "-t", "$u", "-h", "$c", NULL }
	158	},
	159	/* arpanet mail */
	160	{
	161	"/usr/lib/mailers/arpa",
50e67097	162	M_STRIPQ, 0, ArpaLocal,
b3cbe40f EA	163	{ "...arpa%mail", "$f", "$h", "$u", NULL }
	164	},
	165	/* uucp mail (cheat & use Bell's v7 mail) */
	166	{
b3cbe40f	167	"/bin/mail",
df2fb49b	168	M_ROPT\|M_STRIPQ, EX_NOUSER, UucpLocal,
b3cbe40f EA	169	# ifdef DUMBMAIL
	170	{ "...uucp%mail", "$h!$u", NULL }
	171	# else
	172	{ "...uucp%mail", "-d", "$h!$u", NULL }
	173	# endif DUMBMAIL
	174	},
	175	};
	176
	177	# define M_LOCAL 0
	178	# define M_BERK 2
	179	# define M_ARPA 3
	180	# define M_UUCP 4
	181
	182
	183
849eaf63 EA	184	struct parsetab ParseTab[] =
	185	{
	186	# ifdef HASARPA
	187	'@', M_ARPA, P_HLAST\|P_USR_UPPER, NULL,
	188	# endif HASARPA
	189	# ifdef HASUUCP
	190	'^', -1, P_MAP, "!",
	191	'!', M_UUCP, 0, NULL,
	192	# endif HASUUCP
	193	'\0', M_LOCAL, P_MOVE, "",
	194	};
b3cbe40f EA	195	\f/*
	196	** GETNAME -- Get the current users login name.
	197	**
	198	** This is in config.c because it is somewhat machine dependent.
	199	** Examine it carefully for your installation.
	200	**
	201	** Algorithm:
	202	** See if the person is logged in. If so, return
	203	** the name s/he is logged in as.
	204	** Look up the user id in /etc/passwd. If found,
	205	** return that name.
	206	** Return NULL.
	207	**
	208	** Parameters:
	209	** none
	210	**
	211	** Returns:
	212	** The login name of this user.
	213	** NULL if this person is noone.
	214	**
	215	** Side Effects:
	216	** none
	217	**
b3cbe40f EA	218	** Called By:
b3cbe40f EA	219	** main
b3cbe40f EA	220	*/
	221
	222	char *
	223	getname()
	224	{
	225	register char *p;
	226	register struct passwd *w;
	227	extern char *getlogin();
	228	extern struct passwd *getpwuid();
	229	static char namebuf[9];
	230
	231	p = getlogin();
	232	if (p != NULL && p[0] != '\0')
	233	return (p);
	234	# ifdef V6
	235	w = getpwuid(getuid() & 0377);
	236	# else
	237	w = getpwuid(getuid());
	238	# endif V6
	239	if (w != NULL)
	240	{
	241	strcpy(namebuf, w->pw_name);
	242	return (namebuf);
	243	}
	244	return (NULL);
	245	}
	246	\f
	247	# ifdef V6
	248	/*
	249	** TTYPATH -- Get the path of the user's tty -- Version 6 version.
	250	**
	251	** Returns the pathname of the user's tty. Returns NULL if
	252	** the user is not logged in or if s/he has write permission
	253	** denied.
	254	**
	255	** Parameters:
	256	** none
	257	**
	258	** Returns:
	259	** pathname of the user's tty.
	260	** NULL if not logged in or write permission denied.
	261	**
	262	** Side Effects:
	263	** none.
	264	**
	265	** WARNING:
	266	** Return value is in a local buffer.
	267	**
b3cbe40f EA	268	** Called By:
b3cbe40f EA	269	** savemail
b3cbe40f EA	270	*/
	271
	272	# include <sys/types.h>
	273	# include <sys/stat.h>
	274
	275	char *
	276	ttypath()
	277	{
	278	struct stat stbuf;
	279	register int i;
	280	static char pathn[] = "/dev/ttyx";
	281	extern int errno;
	282
	283	/* compute the pathname of the controlling tty */
	284	if ((i = ttyn(2)) == 'x' && (i = ttyn(1)) == 'x' && (i = ttyn(0)) == 'x')
	285	{
	286	errno = 0;
	287	return (NULL);
	288	}
	289	pathn[8] = i;
	290
	291	/* see if we have write permission */
	292	if (stat(pathn, &stbuf) < 0 \|\| !flagset(02, stbuf.st_mode))
	293	{
	294	errno = 0;
	295	return (NULL);
	296	}
	297
	298	/* see if the user is logged in */
	299	if (getlogin() == NULL)
	300	return (NULL);
	301
	302	/* looks good */
	303	return (pathn);
	304	}
	305	\f/*
	306	** FDOPEN -- Open a stdio file given an open file descriptor.
	307	**
	308	** This is included here because it is standard in v7, but we
	309	** need it in v6.
	310	**
	311	** Algorithm:
	312	** Open /dev/null to create a descriptor.
	313	** Close that descriptor.
	314	** Copy the existing fd into the descriptor.
	315	**
	316	** Parameters:
	317	** fd -- the open file descriptor.
	318	** type -- "r", "w", or whatever.
	319	**
	320	** Returns:
	321	** The file descriptor it creates.
	322	**
	323	** Side Effects:
	324	** none
	325	**
b3cbe40f EA	326	** Called By:
	327	** deliver
	328	**
	329	** Notes:
	330	** The mode of fd must match "type".
	331	*/
	332
	333	FILE *
	334	fdopen(fd, type)
	335	int fd;
	336	char *type;
	337	{
	338	register FILE *f;
	339
	340	f = fopen("/dev/null", type);
	341	close(fileno(f));
	342	fileno(f) = fd;
	343	return (f);
	344	}
	345	\f/*
	346	** INDEX -- Return pointer to character in string
	347	**
	348	** For V7 compatibility.
	349	**
	350	** Parameters:
	351	** s -- a string to scan.
	352	** c -- a character to look for.
	353	**
	354	** Returns:
	355	** If c is in s, returns the address of the first
	356	** instance of c in s.
	357	** NULL if c is not in s.
	358	**
	359	** Side Effects:
	360	** none.
b3cbe40f EA	361	*/
	362
	363	index(s, c)
	364	register char *s;
	365	register char c;
	366	{
	367	while (*s != '\0')
	368	{
	369	if (*s++ == c)
	370	return (--s);
	371	}
	372	return (NULL);
	373	}
	374	# endif V6
	375	\f
	376	# ifndef V6
	377	/*
	378	** TTYPATH -- Get the path of the user's tty -- Version 7 version.
	379	**
	380	** Returns the pathname of the user's tty. Returns NULL if
	381	** the user is not logged in or if s/he has write permission
	382	** denied.
	383	**
	384	** Parameters:
	385	** none
	386	**
	387	** Returns:
	388	** pathname of the user's tty.
	389	** NULL if not logged in or write permission denied.
	390	**
	391	** Side Effects:
	392	** none.
	393	**
	394	** WARNING:
	395	** Return value is in a local buffer.
	396	**
b3cbe40f EA	397	** Called By:
b3cbe40f EA	398	** savemail
b3cbe40f EA	399	*/
	400
	401	# include <sys/types.h>
	402	# include <sys/stat.h>
	403
	404	char *
	405	ttypath()
	406	{
	407	struct stat stbuf;
	408	register char *pathn;
	409	extern int errno;
	410	extern char *ttyname();
	411
	412	/* compute the pathname of the controlling tty */
	413	if ((pathn = ttyname(2)) == NULL && (pathn = ttyname(1)) == NULL && (pathn = ttyname(0)) == NULL)
	414	{
	415	errno = 0;
	416	return (NULL);
	417	}
	418
	419	/* see if we have write permission */
	420	if (stat(pathn, &stbuf) < 0 \|\| !flagset(02, stbuf.st_mode))
	421	{
	422	errno = 0;
	423	return (NULL);
	424	}
	425
	426	/* see if the user is logged in */
	427	if (getlogin() == NULL)
	428	return (NULL);
	429
	430	/* looks good */
	431	return (pathn);
	432	}
	433	# endif V6