examples/loadables/dirname.c

   1 /* dirname - return directory portion of pathname */
   2
   3 /* See Makefile for compilation details. */
   4
   5 /*
   6    Copyright (C) 1999-2009 Free Software Foundation, Inc.
   7
   8    This file is part of GNU Bash.
   9    Bash is free software: you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation, either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    Bash is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "config.h"
  24
  25 #if defined (HAVE_UNISTD_H)
  26 #  include <unistd.h>
  27 #endif
  28
  29 #include <stdio.h>
  30 #include "builtins.h"
  31 #include "shell.h"
  32 #include "common.h"
  33
  34 dirname_builtin (list)
  35      WORD_LIST *list;
  36 {
  37   int slen;
  38   char *string;
  39
  40   if (list == 0 || list->next)
  41     {
  42       builtin_usage ();
  43       return (EX_USAGE);
  44     }
  45
  46   if (no_options (list))
  47     return (EX_USAGE);
  48
  49   string = list->word->word;
  50   slen = strlen (string);
  51
  52   /* Strip trailing slashes */
  53   while (slen > 0 && string[slen - 1] == '/')
  54     slen--;
  55
  56   /* (2) If string consists entirely of slash characters, string shall be
  57          set to a single slash character.  In this case, skip steps (3)
  58          through (8). */
  59   if (slen == 0)
  60     {
  61       fputs ("/\n", stdout);
  62       return (EXECUTION_SUCCESS);
  63     }
  64
  65   /* (3) If there are any trailing slash characters in string, they
  66          shall be removed. */
  67   string[slen] = '\0';
  68
  69   /* (4) If there are no slash characters remaining in string, string
  70          shall be set to a single period character.  In this case, skip
  71          steps (5) through (8).
  72
  73      (5) If there are any trailing nonslash characters in string,
  74          they shall be removed. */
  75
  76   while (--slen >= 0)
  77     if (string[slen] == '/')
  78       break;
  79
  80   if (slen < 0)
  81     {
  82       fputs (".\n", stdout);
  83       return (EXECUTION_SUCCESS);
  84     }
  85
  86   /* (7) If there are any trailing slash characters in string, they
  87          shall be removed. */
  88   while (--slen >= 0)
  89     if (string[slen] != '/')
  90       break;
  91   string[++slen] = '\0';
  92
  93   /* (8) If the remaining string is empty, string shall be set to a single
  94          slash character. */
  95   printf ("%s\n", (slen == 0) ? "/" : string);
  96   return (EXECUTION_SUCCESS);
  97 }
  98
  99 char *dirname_doc[] = {
 100         "Display directory portion of pathname.",
 101         "",
 102         "The STRING is converted to the name of the directory containing",
 103         "the filename corresponding to the last pathname component in STRING.",
 104         (char *)NULL
 105 };
 106
 107 /* The standard structure describing a builtin command.  bash keeps an array
 108    of these structures. */
 109 struct builtin dirname_struct = {
 110         "dirname",              /* builtin name */
 111         dirname_builtin,        /* function implementing the builtin */
 112         BUILTIN_ENABLED,        /* initial flags for builtin */
 113         dirname_doc,            /* array of long documentation strings. */
 114         "dirname string",       /* usage synopsis */
 115         0                       /* reserved for internal use */
 116 };