usr/src/lib/libast/common/path/pathcd.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23 /*
  24  * K. P. Vo
  25  * G. S. Fowler
  26  * AT&T Research
  27  */
  28
  29 #include <ast.h>
  30 #include <error.h>
  31 #include <stk.h>
  32
  33 #if DEBUG
  34
  35 #undef  PATH_MAX
  36
  37 #define PATH_MAX        16
  38
  39 static int
  40 vchdir(const char* path)
  41 {
  42         int     n;
  43
  44         if (strlen(path) >= PATH_MAX)
  45         {
  46                 errno = ENAMETOOLONG;
  47                 n = -1;
  48         }
  49         else n = chdir(path);
  50         return n;
  51 }
  52
  53 #define chdir(p)        vchdir(p)
  54
  55 #endif
  56
  57 /*
  58  * set the current directory to path
  59  * if path is long and home!=0 then pathcd(home,0)
  60  * is called on intermediate chdir errors
  61  */
  62
  63 int
  64 pathcd(const char* path, const char* home)
  65 {
  66         register char*  p = (char*)path;
  67         register char*  s;
  68         register int    n;
  69         int             i;
  70         int             r;
  71
  72         r = 0;
  73         for (;;)
  74         {
  75                 /*
  76                  * this should work 99% of the time
  77                  */
  78
  79                 if (!chdir(p))
  80                         return r;
  81
  82                 /*
  83                  * chdir failed
  84                  */
  85
  86                 if ((n = strlen(p)) < PATH_MAX)
  87                         return -1;
  88 #ifdef ENAMETOOLONG
  89                 if (errno != ENAMETOOLONG)
  90                         return -1;
  91 #endif
  92
  93                 /*
  94                  * path is too long -- copy so it can be modified in place
  95                  */
  96
  97                 i = stktell(stkstd);
  98                 sfputr(stkstd, p, 0);
  99                 stkseek(stkstd, i);
 100                 p = stkptr(stkstd, i);
 101                 for (;;)
 102                 {
 103                         /*
 104                          * get a short prefix component
 105                          */
 106
 107                         s = p + PATH_MAX;
 108                         while (--s >= p && *s != '/');
 109                         if (s <= p)
 110                                 break;
 111
 112                         /*
 113                          * chdir to the prefix
 114                          */
 115
 116                         *s++ = 0;
 117                         if (chdir(p))
 118                                 break;
 119
 120                         /*
 121                          * do the remainder
 122                          */
 123
 124                         if ((n -= s - p) < PATH_MAX)
 125                         {
 126                                 if (chdir(s))
 127                                         break;
 128                                 return r;
 129                         }
 130                         p = s;
 131                 }
 132
 133                 /*
 134                  * try to recover back to home
 135                  */
 136
 137                 if (!(p = (char*)home))
 138                         return -1;
 139                 home = 0;
 140                 r = -1;
 141         }
 142 }