usr/src/tools/cscope-fast/logdir.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, 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
  49 static char line[BUFSIZ+1];
  50
  51 static char *
  52 passwdfield(char *p)
  53 {
  54         while (*p && *p != ':')
  55                 ++p;
  56         if (*p)
  57                 *p++ = 0;
  58         return (p);
  59 }
  60
  61 char *
  62 logdir(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 }