/* creat_mbox.c
 *
 * This is a program to create a mailbox in a user's directory.
 * It is separate from the main mail programs (send and msg) to
 * minimize the amount of code which must run as the superuser.
 * 
 * Note: THIS PROGRAM MUST BE OWNED BY THE SUPERUSER AND MUST
 *	 RUN WITH THE SET-USER-ID BIT SET.
 *
 * To eliminate hacking, the program is passed just the name of
 * the user for whom the mailbox is to be created.  It searches
 * the password file to find the user's home directory, then
 * checks to see if that user has a .mail.init file.  If so,
 * it gets the mailbox name from the file; otherwise it defaults
 * to the name ".mail".  In either case, it then verifies that the
 * user does not already have a file of that name before
 * creating one.  The new mailbox is created with mode 0622
 * (read/write for owner, write only for everyone else) and its
 * owner is set to the user's uid.
 */

#include	"rqfile.h"
#include	"init_rec.h"

#define	true	1
#define	false	0
char mailbox[64];
char pwbuf[512];
char *pwptr;
int pwcount;
int pwfd;
struct status
	{
	char	s_minor;
	char	s_major;
	int	s_number;
	int	s_mode;
	char	s_nlinks;
	char	s_uid;
	char	s_gid;
	char	s_size0;
	int	s_size1;
	int	s_addr[8];
	int	s_actime[2];
	int	s_modtime[2];
	} statb;
int	uid, gid;
struct	init_rec inir;


main (argc, argv)

int	argc;
char	*argv[];
{
	char	initfile[64];
	int	infd;

	if (argc != 2)
		exit (1);
	if ((pwfd = open ("/etc/passwd", 0)) < 0)
		exit (1);
	if (!findlocal (argv[1]))
		exit (1);
	stcat ("/", mailbox);
	stcpy (mailbox, initfile);
	stcat (INITFILE, initfile);
	if ((infd = open (initfile, 0)) >= 0) {
		read (infd, &inir, sizeof (inir));
		close (infd);
		stcat (inir.in_mail, mailbox);
		}
	else
		stcat (".mail", mailbox);
	if (stat (mailbox, &statb) < 0) {
		close (creat (mailbox, 0622));
		chown (mailbox, (gid << 8)| (uid & 0377));
		exit (0);
		}
	exit (1);
	}


/* name:
	findlocal

function:
	To ascertain whether or not someone is a local user, and
	if they are, to find the name of their root directory.

algorithm:
	Rewind the password file.
	Search it for a line starting with the user name.
	If found:
		extract all the info about uid, gid mailbox, etc.
		return.
	Else, continue the search.
	Announce that he isn't a known user.

parameters:
	*char	pointer to null terminated user name.

returns:
	boolean	whether or not he was found.

globals:
	pwfd
	uid
	gid
	mailbox
	pwcount

calls:
	getpwchar
	seek	(system)

called by:
	send

history:
	Written by Mark Kampe
	Modified by Lauren Weinstein, 3/12/79

 */
findlocal(name)
char *name;
{
register char *np;
register char pwc;

/*	rewind the password file */
seek(pwfd,0,0);
pwcount = 0;

pwc = 1;
while(pwc > 0)
{	np = name;	/* search for a line starting with name */
	for(pwc = getpwchar(); pwc == *np++; pwc = getpwchar());
	if ((pwc == ':') && (*--np == '\000')) goto gotuser;
	while( (pwc != '\n') && (pwc > 0) ) pwc = getpwchar();
}
return(false);

gotuser:	/* extract all neat info from pw entry */
for(pwc = getpwchar(); pwc != ':'; pwc = getpwchar());
/* we have skipped over the password */
for(uid = 0; (pwc = getpwchar()) != ':'; uid =+ (9*uid) + pwc - '0');
for(gid = 0; (pwc = getpwchar()) != ':'; gid =+ (9*gid) + pwc - '0');
for(pwc = getpwchar(); pwc != ':'; pwc = getpwchar ());
np = mailbox;
for(pwc = getpwchar(); pwc != ':'; pwc = getpwchar()) *np++ = pwc;
*np = '\000';
return(true);
}


getpwchar()
{
tryagain:
	if (pwcount > 0)
	{	pwcount--;
		return(*pwptr++);
	}
	else
	{	pwcount = read(pwfd,pwbuf,512);
		if (pwcount <= 0) return(-1);
		pwptr = pwbuf;
		goto tryagain;
	}
}


stcat(latter,former)
char *latter,*former;
{
register char *fp,*lp;
fp = former;
lp = latter;
while (*fp++);
fp--;
while (*fp++ = *lp++);
}

stcpy(latter,former)
char *latter,*former;
{
register char *fp,*lp;
fp = former;
lp = latter;
while (*fp++ = *lp++);
}