SETUP/config/searchp.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
   7  * Reserved.  This file contains Original Code and/or Modifications of
   8  * Original Code as defined in and that are subject to the Apple Public
   9  * Source License Version 1.0 (the 'License').  You may not use this file
  10  * except in compliance with the License.  Please obtain a copy of the
  11  * License at http://www.apple.com/publicsource and read it before using
  12  * this file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  19  * License for the specific language governing rights and limitations
  20  * under the License."
  21  *
  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24 /*  searchp  --  search through pathlist for file
  25  *
  26  *  Usage:  p = searchp (path,file,fullname,func);
  27  *      char *p, *path, *file, *fullname;
  28  *      int (*func)();
  29  *
  30  *  Searchp will parse "path", a list of pathnames separated
  31  *  by colons, prepending each pathname to "file".  The resulting
  32  *  filename will be passed to "func", a function provided by the
  33  *  user.  This function must return zero if the search is
  34  *  successful (i.e. ended), and non-zero if the search must
  35  *  continue.  If the function returns zero (success), then
  36  *  searching stops, the full filename is placed into "fullname",
  37  *  and searchp returns 0.  If the pathnames are all unsuccessfully
  38  *  examined, then searchp returns -1.
  39  *  If "file" begins with a slash, it is assumed to be an
  40  *  absolute pathname and the "path" list is not used.  Note
  41  *  that this rule is used by Bell's cc also; whereas Bell's
  42  *  sh uses the rule that any filename which CONTAINS a slash
  43  *  is assumed to be absolute.  The execlp and execvp procedures
  44  *  also use this latter rule.  In my opinion, this is bogosity.
  45  *
  46  *  HISTORY
  47  * 01-Apr-86  Rudy Nedved (ern) at Carnegie-Mellon University
  48  *      4.1BSD system ignores trailing slashes. 4.2BSD does not.
  49  *      Therefore don't add a seperating slash if there is a null
  50  *      filename.
  51  *
  52  * 23-Oct-82  Steven Shafer (sas) at Carnegie-Mellon University
  53  *      Fixed two bugs: (1) calling function as "func" instead of
  54  *      "(*func)", (2) omitting trailing null name implied by trailing
  55  *      colon in path.  Latter bug fixed by introducing "lastchar" and
  56  *      changing final loop test to look for "*lastchar" instead of
  57  *      "*nextpath".
  58  *
  59  * 20-Nov-79  Steven Shafer (sas) at Carnegie-Mellon University
  60  *      Created for VAX.  If you're thinking of using this, you probably
  61  *      should look at openp() and fopenp() (or the "want..." routines)
  62  *      instead.
  63  *
  64  */
  65 #include "config.h"
  66
  67 int
  68 searchp(const char *spath, char *file, char *fullname, int (*func)(char *))
  69 {
  70         const char *nextpath, *nextchar, *lastchar;
  71         char *fname;
  72         int failure;
  73
  74         nextpath = ((*file == '/') ? "" : spath);
  75         do {
  76                 fname = fullname;
  77                 nextchar = nextpath;
  78                 while (*nextchar && (*nextchar != ':'))
  79                         *fname++ = *nextchar++;
  80                 if (nextchar != nextpath && *file) *fname++ = '/';
  81                 lastchar = nextchar;
  82                 nextpath = ((*nextchar) ? nextchar + 1 : nextchar);
  83                 nextchar = file;        /* append file */
  84                 while (*nextchar)  *fname++ = *nextchar++;
  85                 *fname = '\0';
  86                 failure = (*func) (fullname);
  87         }
  88         while (failure && (*lastchar));
  89         return (failure ? -1 : 0);
  90 }