#
/* getpw.c
 *
 * Get all the usernames and login directories from the password file.
 * Store them in a calloc'ed array.  This is an efficiency hack to
 * avoid having to read through the entire password file each time
 * a message is delivered.  To increase the speed, the array is
 * sorted by uname so binary searching will work.
 * getpwf is also responsible for finding the Daemon's user name in
 * the password file and storing it in the external array me.
 */

#include	<stdio.h>
#include	<inode.h>
#include	"rqfile.h"
#include	"extern.h"

#define	NOPWENT		256		/* max. password entries */
struct	pwent	{			/* saved contents of password file */
	char	*pw_name;		/* user name */
	char	*pw_hdir;		/* home directory */
	} entries[NOPWENT];
char	pwfile[] = "/etc/passwd";	/* password file name */
int	pwmod[2];			/* password file modified time */
int	npwent;				/* number of password file entries */
int	pwcmp ();			/* password compare routine */

getpwf ()
{
	register struct	pwent	*pwp;	/* ptr. to current password ent. */
	register char	*cp;		/* ptr. to current alloc. */
	FILE	*fpasswd;		/* password file */
	char	line[NAMSIZ];		/* password file line */
	char	name[NAMSIZ];		/* current username */
	char	hdir[NAMSIZ];		/* his home directory */
	int	nsiz, dsiz;		/* name & directory lengths */
	struct	inode	buf;		/* buffer for stat call */
	int	myuid, uid;		/* daemon's uid, current uid */

	if ((stat (pwfile, &buf)) < 0)
		faterr ("can't find password file\n");
	pwmod[0] = buf.modtime[0];
	pwmod[1] = buf.modtime[1];
	myuid = getuid();

	if ( (fpasswd = fopen(pwfile,"r")) == NULL)
		faterr ("can't open password file\n");

	pwp = entries;
	npwent = 0;
	while (fgets(line, sizeof(line), fpasswd) != NULL)  {
		sscanf(line, "%32[^:]:%*[^:]:%d:%*[^:]:%*[^:]:%32[^:]:%*s",
		       name, &uid, hdir);
		if (uid == myuid)		/* is this my entry? */
			strcpy (me, name);	/* yes; save my name */
		nsiz = strlen (name);
		dsiz = strlen (hdir);
		if ((cp = alloc (nsiz + dsiz + 2)) == -1)
			faterr ("can't alloc for password file\n");
		pwp->pw_name = cp;
		lccpy (cp, name);
		cp += nsiz + 1;
		pwp->pw_hdir = cp;
		strcpy (cp, hdir);
		if (++pwp >= &entries[NOPWENT])
			faterr ("password file too large\n");
		npwent++;
		}
	fclose (fpasswd);
	qsort (entries, npwent, sizeof (struct pwent), &pwcmp);
	}


/* Check if password file was modified; if so, update saved password entries.
 * Called each time the mail daemon is awakened.
 */

chkpwd ()
{
	struct	inode	buf;		/* buf for stat call */
	register struct	pwent	*pwp;	/* ptr. to current password ent. */
	register int	i;		/* index in entries array */

	if ((stat (pwfile, &buf)) < 0)
		faterr ("can't find password file\n");
	if (pwmod[0] == buf.modtime[0] && pwmod[1] == buf.modtime[1])
		return;
	for (pwp = entries, i = 0; i < npwent; i++, pwp++) {
		free (pwp->pw_name);
		pwp->pw_name = NULL;
		pwp->pw_hdir = NULL;
		}
	getpwf ();
	}


/* Find the password file entry for the specified user, if one exists.
 * Return that user's home directory, or NULL if no such user exists.
 * Uses a binary search for speed.
 */

getpwent (uname, hdir)

char	*uname;				/* user name to be found */
char	*hdir;				/* user's home directory */
{
	register int	pwp;		/* password entry index */
	struct	pwent	pe;		/* temp entry for compares */

	pe.pw_name = uname;
	pe.pw_hdir = hdir;
	if ((pwp = binsrch ((char *)&pe, (char *)entries, npwent,
			sizeof (struct pwent), &pwcmp)) == -1)
		return (NULL);
	strcpy (hdir, entries[pwp].pw_hdir);
	return (hdir);
	}


/* Compare two password entries on the uname field.  Returns <, =, or
 * > 0 as the first uname is lexically less than, equal to, or greater
 * than the second.
 */

pwcmp (pent1, pent2)

register struct	pwent	*pent1;
register struct	pwent	*pent2;
{
	return (lwccmp (&pent1->pw_name, &pent2->pw_name));
	}

#define	tolower(c)	((c) >= 'A' && (c) <= 'Z' ? (c) + 'a' - 'A' : (c))

/* Lower-case copy a string.  Used for user names - all are mapped into
 * lower-case.
 */

lccpy(to, from)

register char	*to, *from;
{
	while (*from != '\0') {
		*to++ = tolower(*from);
		from++;
	}
	*to = '\0';
}