#
/* getpm.c
 *
 * Get all the personal computer mail usernames and mail file names from
 * the users file.  Store them in a calloc'ed array.  This is an efficiency
 * hack to avoid having to read through the entire users file each time
 * a message is delivered.  To increase the speed, the array is
 * sorted by uname so binary searching will work.
 */

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

#define	NOPMENT		256		/* max. user entries */
struct	pment	{			/* saved contents of users file */
	char	*pm_name;		/* user name */
	char	*pm_file;		/* mail file */
	} entries[NOPMENT];
char	pmfile[] = "/pmail/users";	/* users file name */
int	pmmod[2];			/* users file modified time */
int	npment;				/* number of user entries */
int	pwcmp ();			/* username compare routine */

getpmf ()
{
	register struct	pment	*pmp;	/* ptr. to current user entry */
	register char	*cp;		/* ptr. to current alloc. */
	FILE	*ufile;			/* users file */
	char	line[NAMSIZ];		/* users file line */
	char	name[NAMSIZ];		/* current username */
	char	file[NAMSIZ];		/* his mail file */
	int	nsiz, fsiz;		/* name & file lengths */
	struct	inode	buf;		/* buffer for stat call */

	if ((stat (pmfile, &buf)) < 0)
		faterr ("can't find pmail users file\n");
	pmmod[0] = buf.modtime[0];
	pmmod[1] = buf.modtime[1];

	if ( (ufile = fopen(pmfile,"r")) == NULL)
		faterr ("can't open pmail users file\n");

	pmp = entries;
	npment = 0;
	while (fgets(line, sizeof(line), ufile) != NULL)  {
		sscanf(line, "%32[^:]:%32[^:]:", name, file);
		nsiz = strlen (name);
		fsiz = strlen (file);
		if ((cp = alloc (nsiz + fsiz + 2)) == -1)
			faterr ("can't alloc for pmail user entry\n");
		pmp->pm_name = cp;
		strcpy (cp, name);
		cp += nsiz + 1;
		pmp->pm_file = cp;
		strcpy (cp, file);
		if (++pmp >= &entries[NOPMENT])
			faterr ("too many pmail users\n");
		npment++;
		}
	fclose (ufile);
	qsort (entries, npment, sizeof (struct pment), &pwcmp);
	}


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

chkpmd ()
{
	struct	inode	buf;		/* buf for stat call */
	register struct	pment	*pmp;	/* ptr. to current user entry */
	register int	i;		/* index in entries array */

	if ((stat (pmfile, &buf)) < 0)
		faterr ("can't find pmail users file\n");
	if (pmmod[0] == buf.modtime[0] && pmmod[1] == buf.modtime[1])
		return;
	for (pmp = entries, i = 0; i < npment; i++, pmp++) {
		free (pmp->pm_name);
		pmp->pm_name = NULL;
		pmp->pm_file = NULL;
		}
	getpmf ();
	}


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

getpment (uname, file)

char	*uname;				/* user name to be found */
char	*file;				/* user's mail file name */
{
	register int	pmp;		/* user entry index */
	struct	pment	pe;		/* temp entry for compares */

	pe.pm_name = uname;
	pe.pm_file = file;
	if ((pmp = binsrch ((char *)&pe, (char *)entries, npment,
			sizeof (struct pment), &pwcmp)) == -1)
		return (NULL);
	strcpy (file, entries[pmp].pm_file);
	return (file);
	}