lib/libc/locale/aliasname.c

   1 /* $NetBSD: aliasname.c,v 1.2.34.1 2009/01/04 17:02:19 christos Exp $ */
   2
   3 /*-
   4  * Copyright (c)2002 YAMAMOTO Takashi,
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 __RCSID("$NetBSD: aliasname.c,v 1.2.34.1 2009/01/04 17:02:19 christos Exp $");
  32 #endif /* LIBC_SCCS and not lint */
  33
  34 #include "namespace.h"
  35 #include <assert.h>
  36 #include <stdio.h>
  37 #include <string.h>
  38
  39 #include "aliasname_local.h"
  40
  41 __inline int __is_ws(char);
  42
  43 __inline int __is_ws(char ch)
  44 {
  45
  46         return (ch == ' ' || ch == '\t');
  47 }
  48
  49 const char *
  50 __unaliasname(const char *dbname, const char *alias, void *buf, size_t bufsize)
  51 {
  52         FILE *fp = NULL;
  53         const char *result = NULL;
  54         size_t resultlen;
  55         size_t aliaslen;
  56         const char *p;
  57         size_t len;
  58
  59         _DIAGASSERT(dbname != NULL);
  60         _DIAGASSERT(alias != NULL);
  61         _DIAGASSERT(buf != NULL);
  62
  63         fp = fopen(dbname, "r");
  64         if (fp == NULL)
  65                 goto quit;
  66
  67         aliaslen = strlen(alias);
  68
  69         while (/*CONSTCOND*/ 1) {
  70                 p = fgetln(fp, &len);
  71                 if (p == NULL)
  72                         goto quit; /* eof or error */
  73
  74                 _DIAGASSERT(len != 0);
  75
  76                 /* ignore terminating NL */
  77                 if (p[len - 1] == '\n')
  78                         len--;
  79
  80                 /* ignore null line and comment */
  81                 if (len == 0 || p[0] == '#')
  82                         continue;
  83
  84                 if (aliaslen > len)
  85                         continue;
  86
  87                 if (memcmp(alias, p, aliaslen))
  88                         continue;
  89
  90                 p += aliaslen;
  91                 len -= aliaslen;
  92
  93                 if (len == 0 || !__is_ws(*p))
  94                         continue;
  95
  96                 /* entry was found here */
  97                 break;
  98
  99                 /* NOTREACHED */
 100         }
 101
 102         /* skip white spaces */
 103         do {
 104                 p++;
 105                 len--;
 106         } while (len != 0 && __is_ws(*p));
 107
 108         if (len == 0)
 109                 goto quit;
 110
 111         /* count length of result */
 112         resultlen = 0;
 113         while (resultlen < len && !__is_ws(*p))
 114                 resultlen++;
 115
 116         /* check if space is enough */
 117         if (bufsize < resultlen + 1)
 118                 goto quit;
 119
 120         memcpy(buf, p, resultlen);
 121         ((char *)buf)[resultlen] = 0;
 122         result = buf;
 123
 124 quit:
 125         if (fp)
 126                 fclose(fp);
 127
 128         return result;
 129 }