Added sys_close and sys_fsync

Untested.

tasks/fs0/include/syscalls.h

@@ -19,6 +19,7 @@ int pager_sys_read(l4id_t sender, unsigned long vnum, unsigned long f_offset,
 int pager_sys_write(l4id_t sender, unsigned long vnum, unsigned long f_offset,
 		   unsigned long npages, void *pagebuf);
 
+int pager_sys_close(l4id_t sender, l4id_t closer, int fd);
 int pager_update_stats(l4id_t sender, unsigned long vnum,
 		       unsigned long newsize);
 #endif /* __FS0_SYSCALLS_H__ */

tasks/fs0/main.c

@@ -92,6 +92,9 @@ void handle_fs_requests(void)
 		pager_sys_write(sender, (unsigned long)mr[0], (unsigned long)mr[1],
 			        (unsigned long)mr[2], (void *)mr[3]);
 		break;
+	case L4_IPC_TAG_PAGER_CLOSE:
+		pager_sys_close(sender, (l4id_t)mr[0], (int)mr[1]);
+		break;
 	case L4_IPC_TAG_PAGER_UPDATE_STATS:
 		pager_update_stats(sender, (unsigned long)mr[0],
 				   (unsigned long)mr[1]);

tasks/fs0/src/syscalls.c

@@ -93,6 +93,30 @@ struct vnode *vfs_create(struct tcb *task, struct pathdata *pdata,
 	return newnode;
 }
 
+/* Pager notifies vfs about a closed file descriptor.
+ *
+ * FIXME: fsync + close could be done under a single "close" ipc
+ * from pager. Currently there are 2 ipcs: 1 fsync + 1 fd close. 
+ */
+int pager_sys_close(l4id_t sender, l4id_t closer, int fd)
+{
+	struct tcb *task;
+	int err;
+
+	BUG_ON(!(task = find_task(sender)));
+
+	if ((err = id_del(task->fdpool, task->fd[fd])) < 0) {
+		printf("%s: Error releasing fd identifier.\n",
+		       __FUNCTION__);
+		l4_ipc_return(err);
+		return 0;
+	}
+	task->fd[fd] = -1;
+
+	l4_ipc_return(0);
+	return 0;
+}
+
 /* FIXME:
  * - Is it already open?
  * - Allocate a copy of path string since lookup destroys it

tasks/libl4/include/l4lib/ipcdefs.h

@@ -45,13 +45,15 @@
 #define L4_IPC_TAG_FORK			22
 #define L4_IPC_TAG_STAT			23
 #define L4_IPC_TAG_FSTAT		24
+#define L4_IPC_TAG_FSYNC		25	/* Pager notifies vfs of file close */
 
 
 /* Tags for ipc between fs0 and mm0 */
-#define L4_IPC_TAG_TASKDATA		25
-#define L4_IPC_TAG_PAGER_OPEN		26	/* vfs sends the pager open file data. */
-#define L4_IPC_TAG_PAGER_READ		27	/* Pager reads file contents from vfs */
-#define L4_IPC_TAG_PAGER_WRITE		28	/* Pager writes file contents to vfs */
-#define L4_IPC_TAG_PAGER_UPDATE_STATS	29	/* Pager updates file stats in vfs */
+#define L4_IPC_TAG_TASKDATA		40
+#define L4_IPC_TAG_PAGER_OPEN		41	/* vfs sends the pager open file data. */
+#define L4_IPC_TAG_PAGER_READ		42	/* Pager reads file contents from vfs */
+#define L4_IPC_TAG_PAGER_WRITE		43	/* Pager writes file contents to vfs */
+#define L4_IPC_TAG_PAGER_CLOSE		44	/* Pager notifies vfs of file close */
+#define L4_IPC_TAG_PAGER_UPDATE_STATS	45	/* Pager updates file stats in vfs */
 
 #endif /* __IPCDEFS_H__ */

tasks/libposix/close.c

@@ -1,5 +1,5 @@
 /*
- * l4/posix glue for close()
+ * l4/posix glue for close() and fsync()
  *
  * Copyright (C) 2007 Bahadir Balban
  */
@@ -44,3 +44,34 @@ int close(int fd)
 	return ret;
 }
 
+static inline int l4_fsync(int fd)
+{
+	write_mr(L4SYS_ARG0, fd);
+
+	/* Call pager with close() request. Check ipc error. */
+	if ((fd = l4_sendrecv(PAGER_TID, PAGER_TID, L4_IPC_TAG_FSYNC)) < 0) {
+		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, fd);
+		return fd;
+	}
+	/* Check if syscall itself was successful */
+	if ((fd = l4_get_retval()) < 0) {
+		printf("%s: CLOSE Error: %d.\n", __FUNCTION__, fd);
+		return fd;
+	}
+	return fd;
+}
+
+int fsync(int fd)
+{
+	int ret = l4_fsync(fd);
+
+	/* If error, return positive error code */
+	if (ret < 0) {
+		errno = -ret;
+		return -1;
+	}
+
+	/* else return value */
+	return ret;
+}
+

tasks/mm0/include/file.h

@@ -17,6 +17,8 @@ int vfs_write(unsigned long vnum, unsigned long f_offset, unsigned long npages,
 int sys_read(l4id_t sender, int fd, void *buf, int count);
 int sys_write(l4id_t sender, int fd, void *buf, int count);
 int sys_lseek(l4id_t sender, int fd, off_t offset, int whence);
+int sys_close(l4id_t sender, int fd);
+int sys_fsync(l4id_t sender, int fd);
 
 struct vfs_file_data {
 	unsigned long vnum;

tasks/mm0/main.c

@@ -97,6 +97,14 @@ void handle_requests(void)
 		sys_write(sender, (int)mr[0], (void *)mr[1], (int)mr[2]);
 		break;
 
+	case L4_IPC_TAG_CLOSE:
+		sys_close(sender, (int)mr[0]);
+		break;
+	
+	case L4_IPC_TAG_FSYNC:
+		sys_fsync(sender, (int)mr[0]);
+		break;
+
 	case L4_IPC_TAG_LSEEK:
 		sys_lseek(sender, (int)mr[0], (off_t)mr[1], (int)mr[2]);
 		break;

tasks/mm0/src/file.c

@@ -237,6 +237,31 @@ int vfs_write(unsigned long vnum, unsigned long file_offset,
 	return err;
 }
 
+int vfs_close(l4id_t sender, int fd)
+{
+	int err;
+
+	l4_save_ipcregs();
+
+	write_mr(L4SYS_ARG0, sender);
+	write_mr(L4SYS_ARG1, fd);
+
+	if ((err = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_PAGER_CLOSE)) < 0) {
+		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, err);
+		return err;
+	}
+
+	/* Check if syscall was successful */
+	if ((err = l4_get_retval()) < 0) {
+		printf("%s: Pager to VFS write error: %d.\n", __FUNCTION__, err);
+		return err;
+	}
+
+	l4_restore_ipcregs();
+
+	return err;
+}
+
 /* Writes updated file stats back to vfs. (e.g. new file size) */
 int vfs_update_file_stats(struct vm_file *f)
 {
@@ -255,7 +280,8 @@ int vfs_update_file_stats(struct vm_file *f)
 
 	/* Check if syscall was successful */
 	if ((err = l4_get_retval()) < 0) {
-		printf("%s: Pager to VFS write error: %d.\n", __FUNCTION__, err);
+		printf("%s: Pager to VFS write error: %d.\n",
+		       __FUNCTION__, err);
 		return err;
 	}
 
@@ -285,6 +311,7 @@ int write_file_pages(struct vm_file *f, unsigned long pfn_start,
 	return 0;
 }
 
+/* Flush all dirty file pages and update file stats */
 int flush_file_pages(struct vm_file *f)
 {
 	write_file_pages(f, 0, __pfn(page_align_up(f->length)));
@@ -294,38 +321,67 @@ int flush_file_pages(struct vm_file *f)
 	return 0;
 }
 
-int sys_close(l4id_t sender, int fd)
+/* Given a task and fd syncs all IO on it */
+int fsync_common(l4id_t sender, int fd)
 {
-	struct tcb *task;
 	struct vm_file *f;
-	int retval, err;
+	struct tcb *task;
+	int err;
 
 	/* Get the task */
 	BUG_ON(!(task = find_task(sender)));
 
 	/* Check fd validity */
-	if (fd < 0 || fd > TASK_FILES_MAX || !task->fd[fd].vmfile) {
-		retval = -EBADF;
-		goto out;
-	}
+	if (fd < 0 || fd > TASK_FILES_MAX || !task->fd[fd].vmfile)
+		return -EBADF;
 
 	/* Finish I/O on file */
 	f = task->fd[fd].vmfile;
-	if ((err = flush_file_pages(f)) < 0) {
-		retval = err;
-		goto out;
-	}
+	if ((err = flush_file_pages(f)) < 0)
+		return err;
 
-out:
-	l4_ipc_return(retval);
 	return 0;
 }
 
-int sys_fsync(int fd)
+/* Closes the file descriptor and notifies vfs */
+int fd_close(l4id_t sender, int fd)
 {
+	struct tcb *task;
+	int err;
+
+	/* Get the task */
+	BUG_ON(!(task = find_task(sender)));
+
+	if ((err = vfs_close(task->tid, fd)) < 0)
+		return err;
+
+	task->fd[fd].vnum = 0;
+	task->fd[fd].cursor = 0;
+	task->fd[fd].vmfile = 0;
+
 	return 0;
 }
 
+int sys_close(l4id_t sender, int fd)
+{
+	int err;
+
+	/* Sync the file and update stats */
+	if ((err = fsync_common(sender, fd)) < 0) {
+		l4_ipc_return(err);
+		return 0;
+	}
+	
+	/* Close the file descriptor. */
+	return	fd_close(sender, fd);
+}
+
+int sys_fsync(l4id_t sender, int fd)
+{
+	/* Sync the file and update stats */
+	return fsync_common(sender, fd);
+}
+
 /* FIXME: Add error handling to this */
 /* Extends a file's size by adding it new pages */
 int new_file_pages(struct vm_file *f, unsigned long start, unsigned long end)