Merge pull request #48 from brandonramirez/chmod

Implemented chmod command.  Github issue 35

shell.js

@@ -1111,7 +1111,207 @@ function _exec(command, options, callback) {
 }
 exports.exec = wrap('exec', _exec, {notUnix:true});
 
+var PERMS = (function (base) {
+  return {
+    OTHER_EXEC  : base.EXEC,
+    OTHER_WRITE : base.WRITE,
+    OTHER_READ  : base.READ,
 
+    GROUP_EXEC  : base.EXEC  << 3,
+    GROUP_WRITE : base.WRITE << 3,
+    GROUP_READ  : base.READ << 3,
+
+    OWNER_EXEC  : base.EXEC << 6,
+    OWNER_WRITE : base.WRITE << 6,
+    OWNER_READ  : base.READ << 6,
+
+    // Literal octal numbers are apparently not allowed in "strict" javascript.  Using parseInt is
+    // the preferred way, else a jshint warning is thrown.
+    STICKY      : parseInt('01000', 8),
+    SETGID      : parseInt('02000', 8),
+    SETUID      : parseInt('04000', 8),
+
+    TYPE_MASK   : parseInt('0770000', 8)
+  };
+})({
+  EXEC  : 1,
+  WRITE : 2,
+  READ  : 4
+});
+
+
+//@
+//@ ### chmod(octal_mode, file)
+//@ ### chmod(symbolic_mode, file)
+//@ Available options:
+//@
+//@ + `-v`: output a diagnostic for every file processed//@
+//@ + `-c`: like verbose but report only when a change is made//@
+//@ + `-R`: change files and directories recursively//@
+//@ Examples:
+//@
+//@ ```javascript
+//@ chmod(755, '/Users/brandon')
+//@ chmod('u+x', '/Users/brandon')
+//@ ```
+//@
+//@ Alters the permissions of a file or directory by either specifying the
+//@ absolute permissions in octal form or expressing the changes in symbols.
+//@ This command tries to mimic the POSIX behavior as much as possible.
+//@ Notable exceptions:
+//@ - In symbolic modes, 'a-r' and '-r' are identical.  No consideration is
+//@   given to the umask.
+//@ - There is no "quiet" option since default behavior is to run silent.
+function _chmod(options, mode, filePattern) {
+  if (!filePattern) {
+    if (options.length > 0 && options.charAt(0) === '-') {
+      // Special case where the specified file permissions started with - to subtract perms, which
+      // get picked up by the option parser as command flags.
+      // If we are down by one argument and options starts with -, shift everything over.
+      filePattern = mode;
+      mode = options;
+      options = '';
+    }
+    else {
+      error('You must specify a file.');
+    }
+  }
+
+  options = parseOptions(options, {
+    'R': 'recursive',
+    'c': 'changes',
+    'v': 'verbose'
+  });
+
+  if (typeof filePattern === 'string') {
+    filePattern = [ filePattern ];
+  }
+
+  var files;
+
+  if (options.recursive) {
+    files = [];
+    expand(filePattern).forEach(function addFile(expandedFile) {
+      var stat = fs.lstatSync(expandedFile);
+
+      if (!stat.isSymbolicLink()) {
+        files.push(expandedFile);
+
+        if (stat.isDirectory()) {  // intentionally does not follow symlinks.
+          fs.readdirSync(expandedFile).forEach(function (child) {
+            addFile(expandedFile + '/' + child);
+          });
+        }
+      }
+    });
+  }
+  else {
+    files = expand(filePattern);
+  }
+
+  files.forEach(function innerChmod(file) {
+    file = path.resolve(file);
+    if (!fs.existsSync(file)) {
+      error('File not found: ' + file);
+    }
+
+    // When recursing, don't follow symlinks.
+    if (options.recursive && fs.lstatSync(file).isSymbolicLink()) {
+      return;
+    }
+
+    var perms = fs.statSync(file).mode;
+    var type = perms & PERMS.TYPE_MASK;
+
+    var newPerms = perms;
+
+    if (isNaN(parseInt(mode, 8))) {
+      // parse options
+      mode.split(',').forEach(function (symbolicMode) {
+        /*jshint regexdash:true */
+        var pattern = /([ugoa]*)([=\+-])([rwxXst]*)/i;
+        var matches = pattern.exec(symbolicMode);
+
+        if (matches) {
+          var applyTo = matches[1];
+          var operator = matches[2];
+          var change = matches[3];
+
+          var changeOwner = applyTo.indexOf('u') != -1 || applyTo === 'a' || applyTo === '';
+          var changeGroup = applyTo.indexOf('g') != -1 || applyTo === 'a' || applyTo === '';
+          var changeOther = applyTo.indexOf('o') != -1 || applyTo === 'a' || applyTo === '';
+
+          var changeRead   = change.indexOf('r') != -1;
+          var changeWrite  = change.indexOf('w') != -1;
+          var changeExec   = change.indexOf('x') != -1;
+          var changeSticky = change.indexOf('t') != -1;
+          var changeSetuid = change.indexOf('s') != -1;
+
+          var mask = 0;
+          if (changeOwner) {
+            mask |= (changeRead ? PERMS.OWNER_READ : 0) + (changeWrite ? PERMS.OWNER_WRITE : 0) + (changeExec ? PERMS.OWNER_EXEC : 0) + (changeSetuid ? PERMS.SETUID : 0);
+          }
+          if (changeGroup) {
+            mask |= (changeRead ? PERMS.GROUP_READ : 0) + (changeWrite ? PERMS.GROUP_WRITE : 0) + (changeExec ? PERMS.GROUP_EXEC : 0) + (changeSetuid ? PERMS.SETGID : 0);
+          }
+          if (changeOther) {
+            mask |= (changeRead ? PERMS.OTHER_READ : 0) + (changeWrite ? PERMS.OTHER_WRITE : 0) + (changeExec ? PERMS.OTHER_EXEC : 0);
+          }
+
+          // Sticky bit is special - it's not tied to user, group or other.
+          if (changeSticky) {
+            mask |= PERMS.STICKY;
+          }
+
+          switch (operator) {
+            case '+':
+              newPerms |= mask;
+              break;
+
+            case '-':
+              newPerms &= ~mask;
+              break;
+
+            case '=':
+              newPerms = type + mask;
+
+              // According to POSIX, when using = to explicitly set the permissions, setuid and setgid can never be cleared.
+              if (fs.statSync(file).isDirectory()) {
+                newPerms |= (PERMS.SETUID + PERMS.SETGID) & perms;
+              }
+              break;
+          }
+
+          if (options.verbose) {
+            log(file + ' -> ' + newPerms.toString(8));
+          }
+
+          if (perms != newPerms) {
+            if (!options.verbose && options.changes) {
+              log(file + ' -> ' + newPerms.toString(8));
+            }
+            fs.chmodSync(file, newPerms);
+          }
+        }
+        else {
+          error('Invalid symbolic mode change: ' + symbolicMode);
+        }
+      });
+    }
+    else {
+      // they gave us a full number
+      newPerms = type + parseInt(mode, 8);
+
+      // POSIX rules are that setuid and setgid can only be added using numeric form, but not cleared.
+      if (fs.statSync(file).isDirectory()) {
+        newPerms |= (PERMS.SETUID + PERMS.SETGID) & perms;
+      }
+
+      fs.chmodSync(file, newPerms);
+    }
+  });
+}
+exports.chmod = wrap('chmod', _chmod);
 
 
 //@

test/chmod.js

@@ -0,0 +1,81 @@
+var shell = require('..');
+
+var assert = require('assert'),
+    path = require('path'),
+    fs = require('fs');
+
+shell.config.silent = true;
+
+//
+// Invalids
+//
+
+shell.chmod('blah');  // missing args
+assert.ok(shell.error());
+shell.chmod('893', 'resources/chmod');  // invalid permissions - mode must be in octal
+assert.ok(shell.error());
+
+//
+// Valids
+//
+
+// Test files - the bitmasking is to ignore the upper bits.
+shell.chmod('755', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('777', 8), parseInt('755', 8));
+shell.chmod('644', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('777', 8), parseInt('644', 8));
+
+shell.chmod('o+x', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('007', 8), parseInt('005', 8));
+shell.chmod('644', 'resources/chmod/file1');
+
+shell.chmod('+x', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('777', 8), parseInt('755', 8));
+shell.chmod('644', 'resources/chmod/file1');
+
+// Test setuid
+shell.chmod('u+s', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('4000', 8), parseInt('4000', 8));
+shell.chmod('u-s', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('777', 8), parseInt('644', 8));
+
+// according to POSIX standards at http://linux.die.net/man/1/chmod,
+// setuid is never cleared from a directory unless explicitly asked for.
+shell.chmod('u+s', 'resources/chmod/c');
+shell.chmod('755', 'resources/chmod/c');
+assert.equal(fs.statSync('resources/chmod/c').mode & parseInt('4000', 8), parseInt('4000', 8));
+shell.chmod('u-s', 'resources/chmod/c');
+
+// Test setgid
+shell.chmod('g+s', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('2000', 8), parseInt('2000', 8));
+shell.chmod('g-s', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('777', 8), parseInt('644', 8));
+
+// Test sticky bit
+shell.chmod('+t', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('1000', 8), parseInt('1000', 8));
+shell.chmod('-t', 'resources/chmod/file1');
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('777', 8), parseInt('644', 8));
+assert.equal(fs.statSync('resources/chmod/file1').mode & parseInt('1000', 8), 0);
+
+// Test directories
+shell.chmod('a-w', 'resources/chmod/b/a/b');
+assert.equal(fs.statSync('resources/chmod/b/a/b').mode & parseInt('777', 8), parseInt('555', 8));
+shell.chmod('755', 'resources/chmod/b/a/b');
+
+// Test recursion
+shell.chmod('-R', 'a+w', 'resources/chmod/b');
+assert.equal(fs.statSync('resources/chmod/b/a/b').mode & parseInt('777', 8), parseInt('777', 8));
+shell.chmod('-R', '755', 'resources/chmod/b');
+assert.equal(fs.statSync('resources/chmod/b/a/b').mode & parseInt('777', 8), parseInt('755', 8));
+
+// Test symbolic links w/ recursion  - WARNING: *nix only
+fs.symlinkSync('resources/chmod/b/a', 'resources/chmod/a/b/c/link', 'dir');
+shell.chmod('-R', 'u-w', 'resources/chmod/a/b');
+assert.equal(fs.statSync('resources/chmod/a/b/c').mode & parseInt('700', 8), parseInt('500', 8));
+assert.equal(fs.statSync('resources/chmod/b/a').mode & parseInt('700', 8), parseInt('700', 8));
+shell.chmod('-R', 'u+w', 'resources/chmod/a/b');
+fs.unlinkSync('resources/chmod/a/b/c/link');
+
+shell.exit(123);

test/resources/chmod/file1

@@ -0,0 +1,2 @@
+this is test file 1
+default state should be 0644 (rw-r--r--)