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;
projects / nestedvm.git / blobdiff