xref: /illumos-gate/usr/src/lib/libc/port/gen/getpw.c (revision 581cede61ac9c14d8d4ea452562a567189eead78)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include "lint.h"
33 #include "file64.h"
34 #include <sys/types.h>
35 #include <mtlib.h>
36 #include <ctype.h>
37 #include <thread.h>
38 #include <synch.h>
39 #include <stdio.h>
40 #include "stdiom.h"
41 #include "libc.h"
42 
43 static FILE *pwf;
44 static mutex_t _pwlock = DEFAULTMUTEX;
45 const char *PASSWD = "/etc/passwd";
46 
47 int
48 getpw(uid_t uid, char buf[])
49 {
50 	int n, c;
51 	char *bp;
52 	FILE *fp;
53 	rmutex_t *lk;
54 
55 	if (pwf == NULL) {
56 		fp = fopen(PASSWD, "rF");
57 		lmutex_lock(&_pwlock);
58 		if (pwf == NULL) {
59 			if ((pwf = fp) == NULL) {
60 				lmutex_unlock(&_pwlock);
61 				return (1);
62 			}
63 			fp = NULL;
64 		}
65 		lmutex_unlock(&_pwlock);
66 		if (fp != NULL)		/* someone beat us to it */
67 			(void) fclose(fp);
68 	}
69 
70 	FLOCKFILE(lk, pwf);
71 	_rewind_unlocked(pwf);
72 
73 	for (;;) {
74 		bp = buf;
75 		while ((c = GETC(pwf)) != '\n') {
76 			if (c == EOF) {
77 				FUNLOCKFILE(lk);
78 				return (1);
79 			}
80 			*bp++ = (char)c;
81 		}
82 		*bp = '\0';
83 		bp = buf;
84 		n = 3;
85 		while (--n)
86 			while ((c = *bp++) != ':')
87 				if (c == '\n') {
88 					FUNLOCKFILE(lk);
89 					return (1);
90 				}
91 		while ((c = *bp++) != ':')
92 			if (isdigit(c))
93 				n = n*10+c-'0';
94 			else
95 				continue;
96 		if (n == uid) {
97 			FUNLOCKFILE(lk);
98 			return (0);
99 		}
100 	}
101 }
102