[IO-90] Infinite loop in FileSystemUtils.freeSpaceWindows if share directory empty

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2
• Fix Version/s: 1.3
• Component/s: Utilities

Environment

Windows NT or higher

• Assignee: Unassigned
• Reporter: Thomas Ledoux
• Created: 02/Aug/06 17:13
• Updated: 26/Aug/06 00:06
• Resolved: 26/Aug/06 00:06

Description

When using FileSystemUtils.freeSpaceWindows in an empty share directory, the line containing the free space does not exist which causes an infinite loop (the outerloop doesn't decrease the i index).

In fact to deal with all possible errors, I propose to test the exitCode of the dir command.

Here is a proposed new code for this function :

/**

• Find free space on the Windows platform using the 'dir' command.
  *
• @param path the path to get free space for, including the colon
• @return the amount of free drive space on the drive
• @throws IOException if an error occurs
  */
  long freeSpaceWindows(String path) throws IOException {
  path = FilenameUtils.normalize(path);
  if (path.length() > 2 && path.charAt(1) == ':') { path = path.substring(0, 2); // seems to make it work }

// build and run the 'dir' command
String[] cmdAttrbs = new String[]

{"cmd.exe", "/C", "dir /-c " + path}

;

// read in the output of the command to an ArrayList
BufferedReader in = null;
String line = null;
ArrayList lines = new ArrayList();
int errorLevel = 0;

try {
Process proc = Runtime.getRuntime().exec(cmdAttrbs);
in = new BufferedReader(
new InputStreamReader(proc.getInputStream()));
line = in.readLine();
while (line != null)

{ line = line.toLowerCase().trim(); lines.add(line); line = in.readLine(); }

proc.waitFor();
errorLevel = proc.exitValue();

} finally

{ IOUtils.closeQuietly(in); }

if (lines.size() == 0)

{ // unknown problem, throw exception throw new IOException( "Command line 'dir /-c' did not return any info " + "for command '" + cmdAttrbs[2] + "'"); }

if (errorLevel != 0) {
if (errorLevel == 2)

{ // Empty directory : unable to calculate the freeSpace return Integer.MAX_VALUE; // ??? }

else

{ // unknown problem, throw exception throw new IOException( "Command line 'dir /-c' error [" + errorLevel + "] for command '" + cmdAttrbs[2] + "'"); }

}

// now iterate over the lines we just read and find the LAST
// non-empty line (the free space bytes should be in the last element
// of the ArrayList anyway, but this will ensure it works even if it's
// not, still assuming it is on the last non-blank line)
long bytes = -1;
int i = lines.size() - 1;
int bytesStart = 0;
int bytesEnd = 0;
outerLoop: while (i > 0) {
line = (String) lines.get;
if (line.length() > 0) {
// found it, so now read from the end of the line to find the
// last numeric character on the line, then continue until we
// find the first non-numeric character, and everything between
// that and the last numeric character inclusive is our free
// space bytes count
int j = line.length() - 1;
innerLoop1: while (j >= 0) {
char c = line.charAt(j);
if (Character.isDigit(c))

{ // found the last numeric character, this is the end of // the free space bytes count bytesEnd = j + 1; break innerLoop1; }

j--;
}
innerLoop2: while (j >= 0) {
char c = line.charAt(j);
if (!Character.isDigit(c) && c != ',' && c != '.')

{ // found the next non-numeric character, this is the // beginning of the free space bytes count bytesStart = j + 1; break innerLoop2; }

j--;
}
break outerLoop;
} else

{ // If the last line is empty we are unable to parse the freeSpace throw new IOException( "Command line 'dir /-c' did not return valid info " + "for command '" + cmdAttrbs[2] + "'"); }

}

// remove commas and dots in the bytes count
StringBuffer buf = new StringBuffer(line.substring(bytesStart, bytesEnd));
for (int k = 0; k < buf.length(); k++) {
if (buf.charAt(k) == ',' || buf.charAt(k) == '.')

{ buf.deleteCharAt(k--); }

}
bytes = Long.parseLong(buf.toString());
return bytes;
}