/** Table containing all open file descriptors. (Entries are null if the fd is not in use */
FD[] fds; // package-private for UnixRuntime
boolean closeOnExec[];
-
- /** Table of all current file locks held by this process. */
- Seekable.Lock[] locks;
- public static final int LOCK_MAX = 8;
/** Pointer to a SecurityManager for this process */
SecurityManager sm;
r.startTime = 0;
r.fds = new FD[OPEN_MAX];
for(int i=0;i<OPEN_MAX;i++) if(fds[i] != null) r.fds[i] = fds[i].dup();
- r.locks = new Seekable.Lock[LOCK_MAX];
int totalPages = writePages.length;
r.readPages = new int[totalPages][];
r.writePages = new int[totalPages][];
if(!exec) {
fds = new FD[OPEN_MAX];
closeOnExec = new boolean[OPEN_MAX];
- locks = new Seekable.Lock[LOCK_MAX];
InputStream stdin = win32Hacks ? new Win32ConsoleIS(System.in) : System.in;
addFD(new TerminalFD(stdin));
return i;
}
+ /** Hook for subclasses to do something when the process closes an FD */
+ void _closedFD(FD fd) { }
+
/** Closes file descriptor <i>fdn</i> and removes it from the file descriptor table */
public final boolean closeFD(int fdn) {
if(state == EXITED || state == EXECED) throw new IllegalStateException("closeFD called in inappropriate state");
if(fdn < 0 || fdn >= OPEN_MAX) return false;
if(fds[fdn] == null) return false;
- // release all fcntl locks on this file
- Seekable s = fds[fdn].seekable();
- if (s != null) {
- try {
- for (int i=0; i < LOCK_MAX; i++) {
- if (locks[i] != null && s.equals(locks[i].seekable())) {
- locks[i].release();
- locks[i] = null;
- }
- }
- } catch (IOException e) { throw new RuntimeException(e); }
- }
+ _closedFD(fds[fdn]);
fds[fdn].close();
fds[fdn] = null;
return 0;
}
- private int sys_fcntl(int fdn, int cmd, int arg) throws FaultException {
+ final int sys_fcntl(int fdn, int cmd, int arg) throws FaultException {
int i;
if(fdn < 0 || fdn >= OPEN_MAX) return -EBADFD;
return closeOnExec[fdn] ? 1 : 0;
case F_GETLK:
case F_SETLK:
- try {
- return sys_fcntl_lock(fd, cmd, arg);
- } catch (IOException e) { throw new RuntimeException(e);}
+ if(STDERR_DIAG) System.err.println("WARNING: file locking requires UnixRuntime");
+ return -ENOSYS;
default:
if(STDERR_DIAG) System.err.println("WARNING: Unknown fcntl command: " + cmd);
return -ENOSYS;
}
}
- /** Implements the F_GETLK and F_SETLK cases of fcntl syscall.
- * If l_start = 0 and l_len = 0 the lock refers to the entire file.
- struct flock {
- short l_type; // lock type: F_UNLCK, F_RDLCK, F_WRLCK
- short l_whence; // type of l_start: SEEK_SET, SEEK_CUR, SEEK_END
- long l_start; // starting offset, bytes
- long l_len; // len = 0 means until EOF
- short l_pid; // lock owner
- short l_xxx; // padding
- };
- */
- private int sys_fcntl_lock(FD fd, int cmd, int arg)
- throws FaultException, IOException {
- if (arg == 0) { System.out.println("BAD ARG"); return -EINVAL; }
- int word = memRead(arg);
- int l_start = memRead(arg+4);
- int l_len = memRead(arg+8);
- int l_type = word>>16;
- int l_whence = word&0x00ff;
-
- Seekable s = fd.seekable();
- if (s == null) return -EINVAL;
-
- switch (l_whence) {
- case SEEK_SET: break;
- case SEEK_CUR: l_start += s.pos(); break;
- case SEEK_END: l_start += s.length(); break;
- default: return -1;
- }
-
- if (cmd != F_GETLK && cmd != F_SETLK) return -EINVAL;
-
- if (cmd == F_GETLK) {
- // Check if an l_type lock can be aquired. The only way to
- // do this within the Java API is to try and create a lock.
- Seekable.Lock lock = s.lock(l_start, l_len, l_type == F_RDLCK);
-
- if (lock != null) {
- // no lock exists
- memWrite(arg, SEEK_SET|(F_UNLCK<<16));
- lock.release();
- }
-
- return 0;
- }
-
- // now processing F_SETLK
- if (cmd != F_SETLK) return -EINVAL;
-
- if (l_type == F_UNLCK) {
- // release all locks that fall within the boundaries given
- for (int i=0; i < LOCK_MAX; i++) {
- if (locks[i] == null || !s.equals(locks[i].seekable()))
- continue;
-
- int pos = (int)locks[i].position();
- if (pos < l_start) continue;
- if (l_start != 0 && l_len != 0) // start/len 0 means unlock all
- if (pos + locks[i].size() > l_start + l_len)
- continue;
-
- locks[i].release();
- locks[i] = null;
- }
- return 0;
-
- } else if (l_type == F_RDLCK || l_type == F_WRLCK) {
- // first see if a lock already exists
- for (int i=0; i < LOCK_MAX; i++) {
- if (locks[i] == null || !s.equals(locks[i].seekable()))
- continue;
- int pos = (int)locks[i].position();
- int size = (int)locks[i].size();
- if (l_start < pos && pos + size < l_start + l_len) {
- // found a lock contained in the new requested lock
- locks[i].release();
- locks[i] = null;
-
- } else if (l_start >= pos && pos + size >= l_start + l_len) {
- // found a lock that contains the requested lock
- if (locks[i].isShared() == (l_type == F_RDLCK)) {
- memWrite(arg+4, pos);
- memWrite(arg+8, size);
- return 0;
- } else {
- locks[i].release();
- locks[i] = null;
- }
- }
- }
-
- // create the lock
- Seekable.Lock lock = s.lock(l_start, l_len, l_type == F_RDLCK);
- if (lock == null) return -EAGAIN;
-
- int i;
- for (i=0; i < LOCK_MAX; i++)
- if (locks[i] == null) break;
- if (i == LOCK_MAX) return -ENOLCK;
- locks[i] = lock;
- return 0;
-
- } else {
- return -EINVAL;
- }
- }
-
-
/** The syscall dispatcher.
The should be called by subclasses when the syscall instruction is invoked.
<i>syscall</i> should be the contents of V0 and <i>a</i>, <i>b</i>, <i>c</i>, and <i>d</i> should be
case SYS_fchown: return sys_fchown(a,b,c);
case SYS_chmod: return sys_chmod(a,b,c);
case SYS_fchmod: return sys_fchmod(a,b,c);
+ case SYS_fcntl: return sys_fcntl_lock(a,b,c);
case SYS_umask: return sys_umask(a);
default: return super._syscall(syscall,a,b,c,d,e,f);
copyout(buf,addr,n);
return n;
}
-
+
+ void _closedFD(FD fd) {
+ // release all fcntl locks on this file
+ Seekable s = fd.seekable();
+ if (s == null) return;
+
+ try {
+ for (int i=0; i < gs.locks.length; i++) {
+ Seekable.Lock l = gs.locks[i];
+ if (l == null) continue;
+ if (s.equals(l.seekable()) && l.getOwner() == this) {
+ l.release();
+ gs.locks[i] = null;
+ }
+ }
+ } catch (IOException e) { throw new RuntimeException(e); }
+ }
+
+ /** Implements the F_GETLK and F_SETLK cases of fcntl syscall.
+ * If l_start = 0 and l_len = 0 the lock refers to the entire file.
+ * Uses GlobalState to ensure locking across processes in the same JVM.
+ struct flock {
+ short l_type; // lock type: F_UNLCK, F_RDLCK, F_WRLCK
+ short l_whence; // type of l_start: SEEK_SET, SEEK_CUR, SEEK_END
+ long l_start; // starting offset, bytes
+ long l_len; // len = 0 means until EOF
+ short l_pid; // lock owner
+ short l_xxx; // padding
+ };
+ */
+ private int sys_fcntl_lock(int fdn, int cmd, int arg) throws FaultException{
+ if (cmd != F_GETLK && cmd != F_SETLK) return sys_fcntl(fdn, cmd, arg);
+
+ if(fdn < 0 || fdn >= OPEN_MAX) return -EBADFD;
+ if(fds[fdn] == null) return -EBADFD;
+ FD fd = fds[fdn];
+
+ if (arg == 0) return -EINVAL;
+ int word = memRead(arg);
+ int l_start = memRead(arg+4);
+ int l_len = memRead(arg+8);
+ int l_type = word>>16;
+ int l_whence = word&0x00ff;
+
+ Seekable.Lock[] locks = gs.locks;
+ Seekable s = fd.seekable();
+ if (s == null) return -EINVAL;
+
+ try {
+
+ switch (l_whence) {
+ case SEEK_SET: break;
+ case SEEK_CUR: l_start += s.pos(); break;
+ case SEEK_END: l_start += s.length(); break;
+ default: return -1;
+ }
+
+ if (cmd == F_GETLK) {
+ // The simple Java file locking below will happily return
+ // a lock that overlaps one already held by the JVM. Thus
+ // we must check over all the locks held by other Runtimes
+ for (int i=0; i < locks.length; i++) {
+ if (locks[i] == null || !s.equals(locks[i].seekable()))
+ continue;
+ if (!locks[i].overlaps(l_start, l_len))
+ continue;
+ if (locks[i].getOwner() == this)
+ continue;
+ if (locks[i].isShared() && l_type == F_RDLCK)
+ continue;
+
+ // overlapping lock held by another process
+ return 0;
+ }
+
+ // check if an area is lockable by attempting to obtain a lock
+ Seekable.Lock lock = s.lock(l_start, l_len, l_type == F_RDLCK);
+
+ if (lock != null) { // no lock exists
+ memWrite(arg, SEEK_SET|(F_UNLCK<<16));
+ lock.release();
+ }
+
+ return 0;
+ }
+
+ // now processing F_SETLK
+ if (cmd != F_SETLK) return -EINVAL;
+
+ if (l_type == F_UNLCK) {
+ // release all locks that fall within the boundaries given
+ for (int i=0; i < locks.length; i++) {
+ if (locks[i] == null || !s.equals(locks[i].seekable()))
+ continue;
+ if (locks[i].getOwner() != this) continue;
+
+ int pos = (int)locks[i].position();
+ if (pos < l_start) continue;
+ if (l_start != 0 && l_len != 0) // start/len 0 means unlock all
+ if (pos + locks[i].size() > l_start + l_len)
+ continue;
+
+ locks[i].release();
+ locks[i] = null;
+ }
+ return 0;
+
+ } else if (l_type == F_RDLCK || l_type == F_WRLCK) {
+ // first see if a lock already exists
+ for (int i=0; i < locks.length; i++) {
+ if (locks[i] == null || !s.equals(locks[i].seekable()))
+ continue;
+
+ if (locks[i].getOwner() == this) {
+ // if this Runtime owns an overlapping lock work with it
+ if (locks[i].contained(l_start, l_len)) {
+ locks[i].release();
+ locks[i] = null;
+ } else if (locks[i].contains(l_start, l_len)) {
+ if (locks[i].isShared() == (l_type == F_RDLCK)) {
+ // return this more general lock
+ memWrite(arg+4, (int)locks[i].position());
+ memWrite(arg+8, (int)locks[i].size());
+ return 0;
+ } else {
+ locks[i].release();
+ locks[i] = null;
+ }
+ }
+ } else {
+ // if another Runtime has an lock and it is exclusive or
+ // we want an exclusive lock then fail
+ if (locks[i].overlaps(l_start, l_len)
+ && (!locks[i].isShared() || l_type == F_WRLCK))
+ return -EAGAIN;
+ }
+ }
+
+ // create the lock
+ Seekable.Lock lock = s.lock(l_start, l_len, l_type == F_RDLCK);
+ if (lock == null) return -EAGAIN;
+ lock.setOwner(this);
+
+ int i;
+ for (i=0; i < locks.length; i++)
+ if (locks[i] == null) break;
+ if (i == locks.length) return -ENOLCK;
+ locks[i] = lock;
+ return 0;
+
+ } else {
+ return -EINVAL;
+ }
+
+ } catch (IOException e) { throw new RuntimeException(e); }
+ }
+
static class SocketFD extends FD {
public static final int TYPE_STREAM = 0;
public static final int TYPE_DGRAM = 1;
final UnixRuntime[] tasks;
int nextPID = 1;
+ /** Table of all current file locks held by this process. */
+ Seekable.Lock[] locks = new Seekable.Lock[16];
+
private MP[] mps = new MP[0];
private FS root;
}
}
- private static final class Jdk14FileLock implements Seekable.Lock {
+ private static final class Jdk14FileLock extends Seekable.Lock {
private final Seekable s;
private final FileLock l;
public void close() throws IOException { is.close(); }
}
- public interface Lock {
- public Seekable seekable();
- public boolean isShared();
- public boolean isValid();
- public void release() throws IOException;
- public long position();
- public long size();
+ public abstract static class Lock {
+ private Object owner = null;
+
+ public abstract Seekable seekable();
+ public abstract boolean isShared();
+ public abstract boolean isValid();
+ public abstract void release() throws IOException;
+ public abstract long position();
+ public abstract long size();
+
+ public void setOwner(Object o) { owner = o; }
+ public Object getOwner() { return owner; }
+
+ public final boolean contains(int start, int len) {
+ return start >= position() && position() + size() >= start + len;
+ }
+
+ public final boolean contained(int start, int len) {
+ return start < position() && position() + size() < start + len;
+ }
+
+ public final boolean overlaps(int start, int len) {
+ return contains(start, len) || contained(start, len);
+ }
}
}
projects / nestedvm.git / commitdiff