logdir.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*	Copyright (c) 1988 AT&T	*/
23/*	  All Rights Reserved  	*/
24
25
26/*
27 * Copyright (c) 1999 by Sun Microsystems, Inc.
28 * All rights reserved.
29 */
30
31#pragma ident	"%Z%%M%	%I%	%E% SMI"
32
33/*
34 *	logdir()
35 *
36 *	This routine does not use the getpwent(3) library routine
37 *	because the latter uses the stdio package.  The allocation of
38 *	storage in this package destroys the integrity of the shell's
39 *	storage allocation.
40 */
41
42#include <fcntl.h>	/* O_RDONLY */
43#include <stdlib.h>
44#include <unistd.h>
45#include <string.h>
46
47#define	BUFSIZ	160
48
49static char line[BUFSIZ+1];
50
51static char *
52passwdfield(char *p)
53{
54	while (*p && *p != ':')
55		++p;
56	if (*p)
57		*p++ = 0;
58	return (p);
59}
60
61char *
62logdir(char *name)
63{
64	char	*p;
65	int	i, j;
66	int	pwf;
67
68	/* attempt to open the password file */
69	if ((pwf = open("/etc/passwd", O_RDONLY)) == -1)
70		return (0);
71
72	/* find the matching password entry */
73	do {
74		/* get the next line in the password file */
75		i = read(pwf, line, BUFSIZ);
76		for (j = 0; j < i; j++)
77			if (line[j] == '\n')
78				break;
79		/* return a null pointer if the whole file has been read */
80		if (j >= i)
81			return (0);
82		line[++j] = 0;			/* terminate the line */
83		/* point at the next line */
84		(void) lseek(pwf, (long)(j - i), 1);
85		p = passwdfield(line);		/* get the logname */
86	} while (*name != *line ||	/* fast pretest */
87	    strcmp(name, line) != 0);
88	(void) close(pwf);
89
90	/* skip the intervening fields */
91	p = passwdfield(p);
92	p = passwdfield(p);
93	p = passwdfield(p);
94	p = passwdfield(p);
95
96	/* return the login directory */
97	(void) passwdfield(p);
98	return (p);
99}
100