usr/src/lib/libc/port/gen/getpw.c

   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 }