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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.io;
18  
19  import java.io.BufferedReader;
20  import java.io.IOException;
21  import java.io.InputStream;
22  import java.io.InputStreamReader;
23  import java.io.OutputStream;
24  import java.util.ArrayList;
25  import java.util.Arrays;
26  import java.util.List;
27  import java.util.StringTokenizer;
28  
29  /**
30   * General File System utilities.
31   * <p>
32   * This class provides static utility methods for general file system
33   * functions not provided via the JDK {@link java.io.File File} class.
34   * <p>
35   * The current functions provided are:
36   * <ul>
37   * <li>Get the free space on a drive
38   * </ul>
39   *
40   * @author Frank W. Zammetti
41   * @author Stephen Colebourne
42   * @author Thomas Ledoux
43   * @author James Urie
44   * @author Magnus Grimsell
45   * @author Thomas Ledoux
46   * @version $Id: FileSystemUtils.java 453889 2006-10-07 11:56:25Z scolebourne $
47   * @since Commons IO 1.1
48   */
49  public class FileSystemUtils {
50  
51      /** Singleton instance, used mainly for testing. */
52      private static final FileSystemUtils INSTANCE = new FileSystemUtils();
53  
54      /** Operating system state flag for error. */
55      private static final int INIT_PROBLEM = -1;
56      /** Operating system state flag for neither Unix nor Windows. */
57      private static final int OTHER = 0;
58      /** Operating system state flag for Windows. */
59      private static final int WINDOWS = 1;
60      /** Operating system state flag for Unix. */
61      private static final int UNIX = 2;
62      /** Operating system state flag for Posix flavour Unix. */
63      private static final int POSIX_UNIX = 3;
64  
65      /** The operating system flag. */
66      private static final int OS;
67      static {
68          int os = OTHER;
69          try {
70              String osName = System.getProperty("os.name");
71              if (osName == null) {
72                  throw new IOException("os.name not found");
73              }
74              osName = osName.toLowerCase();
75              // match
76              if (osName.indexOf("windows") != -1) {
77                  os = WINDOWS;
78              } else if (osName.indexOf("linux") != -1 ||
79                  osName.indexOf("sun os") != -1 ||
80                  osName.indexOf("sunos") != -1 ||
81                  osName.indexOf("solaris") != -1 ||
82                  osName.indexOf("mpe/ix") != -1 ||
83                  osName.indexOf("freebsd") != -1 ||
84                  osName.indexOf("irix") != -1 ||
85                  osName.indexOf("digital unix") != -1 ||
86                  osName.indexOf("unix") != -1 ||
87                  osName.indexOf("mac os x") != -1) {
88                  os = UNIX;
89              } else if (osName.indexOf("hp-ux") != -1 ||
90                  osName.indexOf("aix") != -1) {
91                  os = POSIX_UNIX;
92              } else {
93                  os = OTHER;
94              }
95  
96          } catch (Exception ex) {
97              os = INIT_PROBLEM;
98          }
99          OS = os;
100     }
101 
102     /**
103      * Instances should NOT be constructed in standard programming.
104      */
105     public FileSystemUtils() {
106         super();
107     }
108 
109     //-----------------------------------------------------------------------
110     /**
111      * Returns the free space on a drive or volume by invoking
112      * the command line.
113      * This method does not normalize the result, and typically returns
114      * bytes on Windows, 512 byte units on OS X and kilobytes on Unix.
115      * As this is not very useful, this method is deprecated in favour
116      * of {@link #freeSpaceKb(String)} which returns a result in kilobytes.
117      * <p>
118      * Note that some OS's are NOT currently supported, including OS/390,
119      * OpenVMS and and SunOS 5. (SunOS is supported by <code>freeSpaceKb</code>.)
120      * <pre>
121      * FileSystemUtils.freeSpace("C:");       // Windows
122      * FileSystemUtils.freeSpace("/volume");  // *nix
123      * </pre>
124      * The free space is calculated via the command line.
125      * It uses 'dir /-c' on Windows and 'df' on *nix.
126      *
127      * @param path  the path to get free space for, not null, not empty on Unix
128      * @return the amount of free drive space on the drive or volume
129      * @throws IllegalArgumentException if the path is invalid
130      * @throws IllegalStateException if an error occurred in initialisation
131      * @throws IOException if an error occurs when finding the free space
132      * @since Commons IO 1.1, enhanced OS support in 1.2 and 1.3
133      * @deprecated Use freeSpaceKb(String)
134      *  Deprecated from 1.3, may be removed in 2.0
135      */
136     public static long freeSpace(String path) throws IOException {
137         return INSTANCE.freeSpaceOS(path, OS, false);
138     }
139 
140     //-----------------------------------------------------------------------
141     /**
142      * Returns the free space on a drive or volume in kilobytes by invoking
143      * the command line.
144      * <pre>
145      * FileSystemUtils.freeSpaceKb("C:");       // Windows
146      * FileSystemUtils.freeSpaceKb("/volume");  // *nix
147      * </pre>
148      * The free space is calculated via the command line.
149      * It uses 'dir /-c' on Windows, 'df -kP' on AIX/HP-UX and 'df -k' on other Unix.
150      * <p>
151      * In order to work, you must be running Windows, or have a implementation of
152      * Unix df that supports GNU format when passed -k (or -kP). If you are going
153      * to rely on this code, please check that it works on your OS by running
154      * some simple tests to compare the command line with the output from this class.
155      * If your operating system isn't supported, please raise a JIRA call detailing
156      * the exact result from df -k and as much other detail as possible, thanks.
157      *
158      * @param path  the path to get free space for, not null, not empty on Unix
159      * @return the amount of free drive space on the drive or volume in kilobytes
160      * @throws IllegalArgumentException if the path is invalid
161      * @throws IllegalStateException if an error occurred in initialisation
162      * @throws IOException if an error occurs when finding the free space
163      * @since Commons IO 1.2, enhanced OS support in 1.3
164      */
165     public static long freeSpaceKb(String path) throws IOException {
166         return INSTANCE.freeSpaceOS(path, OS, true);
167     }
168 
169     //-----------------------------------------------------------------------
170     /**
171      * Returns the free space on a drive or volume in a cross-platform manner.
172      * Note that some OS's are NOT currently supported, including OS/390.
173      * <pre>
174      * FileSystemUtils.freeSpace("C:");  // Windows
175      * FileSystemUtils.freeSpace("/volume");  // *nix
176      * </pre>
177      * The free space is calculated via the command line.
178      * It uses 'dir /-c' on Windows and 'df' on *nix.
179      *
180      * @param path  the path to get free space for, not null, not empty on Unix
181      * @param os  the operating system code
182      * @param kb  whether to normalize to kilobytes
183      * @return the amount of free drive space on the drive or volume
184      * @throws IllegalArgumentException if the path is invalid
185      * @throws IllegalStateException if an error occurred in initialisation
186      * @throws IOException if an error occurs when finding the free space
187      */
188     long freeSpaceOS(String path, int os, boolean kb) throws IOException {
189         if (path == null) {
190             throw new IllegalArgumentException("Path must not be empty");
191         }
192         switch (os) {
193             case WINDOWS:
194                 return (kb ? freeSpaceWindows(path) / 1024 : freeSpaceWindows(path));
195             case UNIX:
196                 return freeSpaceUnix(path, kb, false);
197             case POSIX_UNIX:
198                 return freeSpaceUnix(path, kb, true);
199             case OTHER:
200                 throw new IllegalStateException("Unsupported operating system");
201             default:
202                 throw new IllegalStateException(
203                   "Exception caught when determining operating system");
204         }
205     }
206 
207     //-----------------------------------------------------------------------
208     /**
209      * Find free space on the Windows platform using the 'dir' command.
210      *
211      * @param path  the path to get free space for, including the colon
212      * @return the amount of free drive space on the drive
213      * @throws IOException if an error occurs
214      */
215     long freeSpaceWindows(String path) throws IOException {
216         path = FilenameUtils.normalize(path);
217         if (path.length() > 2 && path.charAt(1) == ':') {
218             path = path.substring(0, 2);  // seems to make it work
219         }
220         
221         // build and run the 'dir' command
222         String[] cmdAttribs = new String[] {"cmd.exe", "/C", "dir /-c " + path};
223         
224         // read in the output of the command to an ArrayList
225         List lines = performCommand(cmdAttribs, Integer.MAX_VALUE);
226         
227         // now iterate over the lines we just read and find the LAST
228         // non-empty line (the free space bytes should be in the last element
229         // of the ArrayList anyway, but this will ensure it works even if it's
230         // not, still assuming it is on the last non-blank line)
231         for (int i = lines.size() - 1; i >= 0; i--) {
232             String line = (String) lines.get(i);
233             if (line.length() > 0) {
234                 return parseDir(line, path);
235             }
236         }
237         // all lines are blank
238         throw new IOException(
239                 "Command line 'dir /-c' did not return any info " +
240                 "for path '" + path + "'");
241     }
242 
243     /**
244      * Parses the Windows dir response last line
245      *
246      * @param line  the line to parse
247      * @param path  the path that was sent
248      * @return the number of bytes
249      * @throws IOException if an error occurs
250      */
251     long parseDir(String line, String path) throws IOException {
252         // read from the end of the line to find the last numeric
253         // character on the line, then continue until we find the first
254         // non-numeric character, and everything between that and the last
255         // numeric character inclusive is our free space bytes count
256         int bytesStart = 0;
257         int bytesEnd = 0;
258         int j = line.length() - 1;
259         innerLoop1: while (j >= 0) {
260             char c = line.charAt(j);
261             if (Character.isDigit(c)) {
262               // found the last numeric character, this is the end of
263               // the free space bytes count
264               bytesEnd = j + 1;
265               break innerLoop1;
266             }
267             j--;
268         }
269         innerLoop2: while (j >= 0) {
270             char c = line.charAt(j);
271             if (!Character.isDigit(c) && c != ',' && c != '.') {
272               // found the next non-numeric character, this is the
273               // beginning of the free space bytes count
274               bytesStart = j + 1;
275               break innerLoop2;
276             }
277             j--;
278         }
279         if (j < 0) {
280             throw new IOException(
281                     "Command line 'dir /-c' did not return valid info " +
282                     "for path '" + path + "'");
283         }
284         
285         // remove commas and dots in the bytes count
286         StringBuffer buf = new StringBuffer(line.substring(bytesStart, bytesEnd));
287         for (int k = 0; k < buf.length(); k++) {
288             if (buf.charAt(k) == ',' || buf.charAt(k) == '.') {
289                 buf.deleteCharAt(k--);
290             }
291         }
292         return parseBytes(buf.toString(), path);
293     }
294 
295     //-----------------------------------------------------------------------
296     /**
297      * Find free space on the *nix platform using the 'df' command.
298      *
299      * @param path  the path to get free space for
300      * @param kb  whether to normalize to kilobytes
301      * @param posix  whether to use the posix standard format flag
302      * @return the amount of free drive space on the volume
303      * @throws IOException if an error occurs
304      */
305     long freeSpaceUnix(String path, boolean kb, boolean posix) throws IOException {
306         if (path.length() == 0) {
307             throw new IllegalArgumentException("Path must not be empty");
308         }
309         path = FilenameUtils.normalize(path);
310 
311         // build and run the 'dir' command
312         String flags = "-";
313         if (kb) {
314             flags += "k";
315         }
316         if (posix) {
317             flags += "P";
318         }
319         String[] cmdAttribs = 
320             (flags.length() > 1 ? new String[] {"df", flags, path} : new String[] {"df", path});
321         
322         // perform the command, asking for up to 3 lines (header, interesting, overflow)
323         List lines = performCommand(cmdAttribs, 3);
324         if (lines.size() < 2) {
325             // unknown problem, throw exception
326             throw new IOException(
327                     "Command line 'df' did not return info as expected " +
328                     "for path '" + path + "'- response was " + lines);
329         }
330         String line2 = (String) lines.get(1); // the line we're interested in
331         
332         // Now, we tokenize the string. The fourth element is what we want.
333         StringTokenizer tok = new StringTokenizer(line2, " ");
334         if (tok.countTokens() < 4) {
335             // could be long Filesystem, thus data on third line
336             if (tok.countTokens() == 1 && lines.size() >= 3) {
337                 String line3 = (String) lines.get(2); // the line may be interested in
338                 tok = new StringTokenizer(line3, " ");
339             } else {
340                 throw new IOException(
341                         "Command line 'df' did not return data as expected " +
342                         "for path '" + path + "'- check path is valid");
343             }
344         } else {
345             tok.nextToken(); // Ignore Filesystem
346         }
347         tok.nextToken(); // Ignore 1K-blocks
348         tok.nextToken(); // Ignore Used
349         String freeSpace = tok.nextToken();
350         return parseBytes(freeSpace, path);
351     }
352 
353     //-----------------------------------------------------------------------
354     /**
355      * Parses the bytes from a string.
356      * 
357      * @param freeSpace  the free space string
358      * @param path  the path
359      * @return the number of bytes
360      * @throws IOException if an error occurs
361      */
362     long parseBytes(String freeSpace, String path) throws IOException {
363         try {
364             long bytes = Long.parseLong(freeSpace);
365             if (bytes < 0) {
366                 throw new IOException(
367                         "Command line 'df' did not find free space in response " +
368                         "for path '" + path + "'- check path is valid");
369             }
370             return bytes;
371             
372         } catch (NumberFormatException ex) {
373             throw new IOException(
374                     "Command line 'df' did not return numeric data as expected " +
375                     "for path '" + path + "'- check path is valid");
376         }
377     }
378 
379     //-----------------------------------------------------------------------
380     /**
381      * Performs the os command.
382      *
383      * @param cmdAttribs  the command line parameters
384      * @param max The maximum limit for the lines returned
385      * @return the parsed data
386      * @throws IOException if an error occurs
387      */
388     List performCommand(String[] cmdAttribs, int max) throws IOException {
389         // this method does what it can to avoid the 'Too many open files' error
390         // based on trial and error and these links:
391         // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4784692
392         // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4801027
393         // http://forum.java.sun.com/thread.jspa?threadID=533029&messageID=2572018
394         // however, its still not perfect as the JDK support is so poor
395         // (see commond-exec or ant for a better multi-threaded multi-os solution)
396         
397         List lines = new ArrayList(20);
398         Process proc = null;
399         InputStream in = null;
400         OutputStream out = null;
401         InputStream err = null;
402         BufferedReader inr = null;
403         try {
404             proc = openProcess(cmdAttribs);
405             in = proc.getInputStream();
406             out = proc.getOutputStream();
407             err = proc.getErrorStream();
408             inr = new BufferedReader(new InputStreamReader(in));
409             String line = inr.readLine();
410             while (line != null && lines.size() < max) {
411                 line = line.toLowerCase().trim();
412                 lines.add(line);
413                 line = inr.readLine();
414             }
415             
416             proc.waitFor();
417             if (proc.exitValue() != 0) {
418                 // os command problem, throw exception
419                 throw new IOException(
420                         "Command line returned OS error code '" + proc.exitValue() +
421                         "' for command " + Arrays.asList(cmdAttribs));
422             }
423             if (lines.size() == 0) {
424                 // unknown problem, throw exception
425                 throw new IOException(
426                         "Command line did not return any info " +
427                         "for command " + Arrays.asList(cmdAttribs));
428             }
429             return lines;
430             
431         } catch (InterruptedException ex) {
432             throw new IOException(
433                     "Command line threw an InterruptedException '" + ex.getMessage() +
434                     "' for command " + Arrays.asList(cmdAttribs));
435         } finally {
436             IOUtils.closeQuietly(in);
437             IOUtils.closeQuietly(out);
438             IOUtils.closeQuietly(err);
439             IOUtils.closeQuietly(inr);
440             if (proc != null) {
441                 proc.destroy();
442             }
443         }
444     }
445 
446     /**
447      * Opens the process to the operating system.
448      *
449      * @param cmdAttribs  the command line parameters
450      * @return the process
451      * @throws IOException if an error occurs
452      */
453     Process openProcess(String[] cmdAttribs) throws IOException {
454         return Runtime.getRuntime().exec(cmdAttribs);
455     }
456 
457 }