Added two open() versions to our kernel_interface, that re-try opening read-only, if desired. They are now used in BDirectory and BNode, which formerly failed on read-only devices.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@2677 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/storage/kernel_interface.h

@@ -68,11 +68,25 @@ status_t stat_dev(dev_t dev, fs_info* info);
 	it doesn't already exist). */
 status_t open(const char *path, OpenFlags flags, FileDescriptor &result);
 
-/*! \brief Same as the other version of open() except the file is created with the
+/*!	\brief Same as the first version, but tries to open read-only, if
+		   first the attempt failed with B_READ_ONLY_DEVICE or
+		   B_PERMISSION_DENIED and \a fallBackToReadOnly is \c true.
+*/
+status_t open(const char *path, OpenFlags flags, FileDescriptor &result,
+			  bool fallBackToReadOnly);
+
+/*! \brief Same as the first version of open() except the file is created with the
 	permissions given by creationFlags if it doesn't exist. */
 status_t open(const char *path, OpenFlags flags, CreationFlags creationFlags,
 	FileDescriptor &result);
 
+/*!	\brief Same as the third version, but tries to open read-only, if
+		   first the attempt failed with B_READ_ONLY_DEVICE or
+		   B_PERMISSION_DENIED and \a fallBackToReadOnly is \c true.
+*/
+status_t open(const char *path, OpenFlags flags, CreationFlags creationFlags,
+			  FileDescriptor &result, bool fallBackToReadOnly);
+
 /*! \brief Closes a previously open()ed file. */
 status_t close( FileDescriptor file );
 

src/kits/storage/Directory.cpp

@@ -249,7 +249,7 @@ BDirectory::SetTo(const char *path)
 		// open_dir() does always traverse those. Therefore we open the FD for
 		// BNode (without the O_NOTRAVERSE flag).
 		BPrivate::Storage::FileDescriptor fd = BPrivate::Storage::NullFd;
-		result = BPrivate::Storage::open(path, O_RDWR, fd);
+		result = BPrivate::Storage::open(path, O_RDWR, fd, true);
 		if (result == B_OK) {
 			result = set_fd(fd);
 			if (result != B_OK)

src/kits/storage/Node.cpp

@@ -247,8 +247,10 @@ status_t
 BNode::SetTo(const char *path)
 {
 	Unset();	
-	if (path != NULL) 
-		fCStatus = BPrivate::Storage::open(path, O_RDWR | O_NOTRAVERSE, fFd);
+	if (path != NULL) {
+		fCStatus = BPrivate::Storage::open(path, O_RDWR | O_NOTRAVERSE, fFd,
+										   true);
+	}
 	return fCStatus;
 }
 

src/kits/storage/kernel_interface.POSIX.cpp

@@ -67,6 +67,19 @@ BPrivate::Storage::open( const char *path, OpenFlags flags, FileDescriptor &resu
 	return (result == -1) ? errno : B_OK ;
 }
 
+status_t
+BPrivate::Storage::open( const char *path, OpenFlags flags,
+						 FileDescriptor &result, bool fallBackToReadOnly )
+{
+	status_t error = open(path, flags, result);
+	if (error == B_READ_ONLY_DEVICE || error == B_PERMISSION_DENIED
+		&& fallBackToReadOnly && (flags & O_RWMASK == O_RDWR)) {
+		flags = flags & ~O_RWMASK | O_RDONLY;
+		error = open(path, flags, result);
+	}
+	return error;
+}
+
 /*! Same as the other version of open() except the file is created with the
 	permissions given by creationFlags if it doesn't exist. */
 status_t
@@ -83,6 +96,20 @@ BPrivate::Storage::open( const char *path, OpenFlags flags,
 	return (result == -1) ? errno : B_OK ;
 }
 
+status_t
+BPrivate::Storage::open( const char *path, OpenFlags flags,
+				  CreationFlags creationFlags, FileDescriptor &result,
+				  bool fallBackToReadOnly )
+{
+	status_t error = open(path, flags, creationFlags, result);
+	if (error == B_READ_ONLY_DEVICE || error == B_PERMISSION_DENIED
+		&& fallBackToReadOnly && (flags & O_RWMASK == O_RDWR)) {
+		flags = flags & ~O_RWMASK | O_RDONLY;
+		error = open(path, flags, creationFlags, result);
+	}
+	return error;
+}
+
 status_t
 BPrivate::Storage::close(BPrivate::Storage::FileDescriptor file)
 {