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8262958: (fs) UnixUserDefinedFileAttributeView cleanup

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Reviewed-by: alanb
This commit is contained in:
Sebastian Stenzel 2021-03-30 13:13:08 +00:00 committed by Alan Bateman
parent af02883575
commit daeca3fff2
1 changed files with 38 additions and 76 deletions
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114
src/java.base/unix/classes/sun/nio/fs/UnixUserDefinedFileAttributeView.java
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@ -46,6 +46,9 @@ abstract class UnixUserDefinedFileAttributeView
// namespace for extended user attributes
private static final String USER_NAMESPACE = "user.";
private static final int MIN_LISTXATTR_BUF_SIZE = 1024;
private static final int MAX_LISTXATTR_BUF_SIZE = 32 * 1024;
private byte[] nameAsBytes(UnixPath file, String name) throws IOException {
if (name == null)
throw new NullPointerException("'name' is null");
@ -59,7 +62,7 @@ abstract class UnixUserDefinedFileAttributeView
}
// Parses buffer as array of NULL-terminated C strings.
private List<String> asList(long address, int size) {
private static List<String> asList(long address, int size) {
List<String> list = new ArrayList<>();
int start = 0;
int pos = 0;
@ -70,10 +73,7 @@ abstract class UnixUserDefinedFileAttributeView
unsafe.copyMemory(null, address+start, value,
Unsafe.ARRAY_BYTE_BASE_OFFSET, len);
String s = Util.toString(value);
if (s.startsWith(USER_NAMESPACE)) {
s = s.substring(USER_NAMESPACE.length());
list.add(s);
}
list.add(s);
start = pos + 1;
}
pos++;
@ -81,6 +81,22 @@ abstract class UnixUserDefinedFileAttributeView
return list;
}
// runs flistxattr, increases buffer size up to MAX_LISTXATTR_BUF_SIZE if required
private static List<String> list(int fd, int bufSize) throws UnixException {
try {
try (NativeBuffer buffer = NativeBuffers.getNativeBuffer(bufSize)) {
int n = flistxattr(fd, buffer.address(), bufSize);
return asList(buffer.address(), n);
} // release buffer before recursion
} catch (UnixException x) {
if (x.errno() == ERANGE && bufSize < MAX_LISTXATTR_BUF_SIZE) {
return list(fd, bufSize * 2); // try larger buffer size:
} else {
throw x;
}
}
}
private final UnixPath file;
private final boolean followLinks;
@ -105,32 +121,17 @@ abstract class UnixUserDefinedFileAttributeView
} catch (UnixException x) {
x.rethrowAsIOException(file);
}
NativeBuffer buffer = null;
try {
int size = 1024;
buffer = NativeBuffers.getNativeBuffer(size);
for (;;) {
try {
int n = flistxattr(fd, buffer.address(), size);
List<String> list = asList(buffer.address(), n);
return Collections.unmodifiableList(list);
} catch (UnixException x) {
// allocate larger buffer if required
if (x.errno() == ERANGE && size < 32*1024) {
buffer.release();
size *= 2;
buffer = null;
buffer = NativeBuffers.getNativeBuffer(size);
continue;
}
throw new FileSystemException(file.getPathForExceptionMessage(),
null, "Unable to get list of extended attributes: " +
x.getMessage());
}
}
List<String> attrNames = list(fd, MIN_LISTXATTR_BUF_SIZE);
return attrNames.stream()
.filter(s -> s.startsWith(USER_NAMESPACE))
.map(s -> s.substring(USER_NAMESPACE.length()))
.toList();
} catch (UnixException x) {
throw new FileSystemException(file.getPathForExceptionMessage(),
null, "Unable to get list of extended attributes: " +
x.getMessage());
} finally {
if (buffer != null)
buffer.release();
close(fd);
}
}
@ -312,57 +313,18 @@ abstract class UnixUserDefinedFileAttributeView
* file descriptor for target file
*/
static void copyExtendedAttributes(int ofd, int nfd) {
NativeBuffer buffer = null;
try {
// call flistxattr to get list of extended attributes.
int size = 1024;
buffer = NativeBuffers.getNativeBuffer(size);
for (;;) {
List<String> attrNames = list(ofd, MIN_LISTXATTR_BUF_SIZE);
for (String name : attrNames) {
try {
size = flistxattr(ofd, buffer.address(), size);
break;
} catch (UnixException x) {
// allocate larger buffer if required
if (x.errno() == ERANGE && size < 32*1024) {
buffer.release();
size *= 2;
buffer = null;
buffer = NativeBuffers.getNativeBuffer(size);
continue;
}
// unable to get list of attributes
return;
copyExtendedAttribute(ofd, Util.toBytes(name), nfd);
} catch(UnixException ignore){
// ignore
}
}
// parse buffer as array of NULL-terminated C strings.
long address = buffer.address();
int start = 0;
int pos = 0;
while (pos < size) {
if (unsafe.getByte(address + pos) == 0) {
// extract attribute name and copy attribute to target.
// FIXME: We can avoid needless copying by using address+pos
// as the address of the name.
int len = pos - start;
byte[] name = new byte[len];
unsafe.copyMemory(null, address+start, name,
Unsafe.ARRAY_BYTE_BASE_OFFSET, len);
try {
copyExtendedAttribute(ofd, name, nfd);
} catch (UnixException ignore) {
// ignore
}
start = pos + 1;
}
pos++;
}
} finally {
if (buffer != null)
buffer.release();
} catch (UnixException e) {
// unable to get list of attributes
return;
}
}