Added per-task curdir. and chdir, pager_read/write, mmap and munmap calls.

They look like what they should look like, but untested.

tasks/fs0/src/memfs/file.c

@@ -16,7 +16,7 @@
 
 #if 0
 
-/* 
+/*
  * FIXME: read_write() could be more layered using these functions.
  */
 void *memfs_read_block(struct vnode *v, int blknum)

tasks/fs0/src/memfs/memfs.c

@@ -66,6 +66,12 @@ int memfs_format_filesystem(void *buffer)
 	INIT_LIST_HEAD(&sb->inode_cache_list);
 	memfs_init_caches(sb);
 
+	/*
+	 * TODO: Make sure root vnode has a vnode number of 0 !!!.
+	 * This is used in early root lookup.
+	 */
+	BUG();
+
 	/* We allocate and fix a root inode so the sb is ready for mount */
 	sb->root = memfs_create_inode(sb);
 

tasks/fs0/src/syscalls.c

@@ -25,7 +25,7 @@
  * for handling syscalls that access file content (i.e. read/write) since
  * it maintains the page cache.
  */
-int send_pager_sys_open(l4id_t sender, int fd, unsigned long vnum, unsigned long size)
+int pager_sys_open(l4id_t sender, int fd, unsigned long vnum, unsigned long size)
 {
 	int err;
 
@@ -34,7 +34,7 @@ int send_pager_sys_open(l4id_t sender, int fd, unsigned long vnum, unsigned long
 	write_mr(L4SYS_ARG2, vnum);
 	write_mr(L4SYS_ARG3, size);
 
-	if ((err = l4_send(PAGER_TID, L4_IPC_TAG_PAGER_SYSOPEN)) < 0) {
+	if ((err = l4_send(PAGER_TID, L4_IPC_TAG_PAGER_OPEN)) < 0) {
 		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, err);
 		return err;
 	}
@@ -43,7 +43,7 @@ int send_pager_sys_open(l4id_t sender, int fd, unsigned long vnum, unsigned long
 }
 
 /* Creates a node under a directory, e.g. a file, directory. */
-int vfs_create(const char *pathname, unsigned int mode)
+int vfs_create(struct tcb *task, const char *pathname, unsigned int mode)
 {
 	char *pathbuf = alloca(strlen(pathname) + 1);
 	char *parentpath = pathbuf;
@@ -57,7 +57,7 @@ int vfs_create(const char *pathname, unsigned int mode)
 	nodename = splitpath_end(&parentpath, '/');
 
 	/* Check that the parent directory exists. */
-	if (IS_ERR(vparent = vfs_lookup_bypath(vfs_root.pivot->sb, parentpath)))
+	if (IS_ERR(vparent = vfs_lookup_bypath(task, parentpath)))
 		return (int)vparent;
 
 	/* The parent vnode must be a directory. */
@@ -80,58 +80,127 @@ int sys_open(l4id_t sender, const char *pathname, int flags, unsigned int mode)
 {
 	char *pathbuf = alloca(strlen(pathname) + 1);
 	struct vnode *v;
-	struct tcb *t;
+	struct tcb *task;
 	int fd;
 	int err;
 
 	strcpy(pathbuf, pathname);
 
+	/* Get the task */
+	BUG_ON(!(task = find_task(sender)));
+
 	/* Get the vnode */
-	if (IS_ERR(v = vfs_lookup_bypath(vfs_root.pivot->sb, pathbuf))) {
+	if (IS_ERR(v = vfs_lookup_bypath(task, pathbuf))) {
 		if (!flags & O_CREAT) {
 			return (int)v;
 		} else {
-			if ((err = vfs_create(pathname, mode)) < 0)
+			if ((err = vfs_create(task, pathname, mode)) < 0)
 				return err;
 		}
 	}
-	/* Get the task */
-	BUG_ON(!(t = find_task(sender)));
 
 	/* Get a new fd */
-	BUG_ON(!(fd = id_new(t->fdpool)));
+	BUG_ON(!(fd = id_new(task->fdpool)));
 
 	/* Assign the new fd with the vnode's number */
-	t->fd[fd] = v->vnum;
+	task->fd[fd] = v->vnum;
 
 	/* Tell the pager about opened vnode information */
-	BUG_ON(send_pager_sys_open(sender, fd, v->vnum, v->size) < 0);
+	BUG_ON(pager_sys_open(sender, fd, v->vnum, v->size) < 0);
 
 	return 0;
 }
 
 int sys_mkdir(l4id_t sender, const char *pathname, unsigned int mode)
 {
-	return vfs_create(pathname, mode);
+	struct tcb *task;
+
+	/* Get the task */
+	BUG_ON(!(task = find_task(sender)));
+
+	return vfs_create(task, pathname, mode);
 }
 
-int sys_read(l4id_t sender, int fd, void *buf, int count)
+int sys_chdir(l4id_t sender, const char *pathname)
 {
-	return 0;
-}
+	char *pathbuf = alloca(strlen(pathname) + 1);
+	struct vnode *v;
+	struct tcb *task;
 
-int sys_write(l4id_t sender, int fd, const void *buf, int count)
-{
-	return 0;
-}
+	strcpy(pathbuf, pathname);
+
+	/* Get the task */
+	BUG_ON(!(task = find_task(sender)));
+
+	/* Get the vnode */
+	if (IS_ERR(v = vfs_lookup_bypath(task, pathbuf)))
+		return (int)v;
+
+	/* Ensure it's a directory */
+	if (!vfs_isdir(v))
+		return -ENOTDIR;
+
+	/* Assign the current directory pointer */
+	task->curdir = v;
 
-int sys_lseek(l4id_t sender, int fd, int offset, int whence)
-{
 	return 0;
 }
 
 /*
- * Reads @count bytes of posix struct dirents into @buf
+ * Note this can be solely called by the pager and is not the posix read call.
+ * That call is in the pager. This merely supplies the pages the pager needs
+ * if they're not in the page cache.
+ */
+int pager_sys_read(l4id_t sender, unsigned long vnum, unsigned long f_offset,
+		   unsigned long npages, void *pagebuf)
+{
+	struct vnode *v;
+	int err;
+
+	if (sender != PAGER_TID)
+		return -EINVAL;
+
+	/* Lookup vnode */
+	if (!(v = vfs_lookup_byvnum(vfs_root.pivot->sb, vnum)))
+		return -EINVAL; /* No such vnode */
+
+	/* Ensure vnode is not a directory */
+	if (vfs_isdir(v))
+		return -EISDIR;
+
+	if ((err = v->fops.read(v, f_offset, npages, pagebuf)) < 0)
+		return err;
+
+	return 0;
+}
+
+int pager_sys_write(l4id_t sender, unsigned long vnum, unsigned long f_offset,
+		   unsigned long npages, void *pagebuf)
+{
+	struct vnode *v;
+	int err;
+
+	if (sender != PAGER_TID)
+		return -EINVAL;
+
+	/* Lookup vnode */
+	if (!(v = vfs_lookup_byvnum(vfs_root.pivot->sb, vnum)))
+		return -EINVAL; /* No such vnode */
+
+	/* Ensure vnode is not a directory */
+	if (vfs_isdir(v))
+		return -EISDIR;
+
+	if ((err = v->fops.write(v, f_offset, npages, pagebuf)) < 0)
+		return err;
+
+	return 0;
+}
+
+/*
+ * Reads @count bytes of posix struct dirents into @buf. This implements
+ * the raw dirent read syscall upon which readdir() etc. posix calls
+ * can be built in userspace.
  */
 int sys_readdir(l4id_t sender, int fd, void *buf, int count)
 {

tasks/fs0/src/task.c

@@ -11,6 +11,8 @@
 #include <l4lib/ipcdefs.h>
 #include <lib/malloc.h>
 #include <task.h>
+#include <vfs.h>
+
 
 struct tcb_head {
 	struct list_head list;
@@ -88,10 +90,12 @@ int init_task_structs(l4id_t *tdata)
 	struct tcb *t;
 	int total = tdata[0];
 
-	for (int i = 0; i < total; i++)
+	for (int i = 0; i < total; i++) {
 		if (IS_ERR(t = create_tcb(tdata[1 + i])))
 			return (int)t;
-
+		t->rootdir = vfs_root.pivot;
+		t->curdir = vfs_root.pivot;
+	}
 	return 0;
 }
 

tasks/fs0/src/vfs.c

@@ -5,6 +5,7 @@
  */
 #include <fs.h>
 #include <vfs.h>
+#include <task.h>
 
 struct list_head vnode_cache;
 struct list_head dentry_cache;
@@ -56,22 +57,25 @@ struct vnode *vfs_lookup_byvnum(struct superblock *sb, unsigned long vnum)
  * have, the other is their vnum. This one checks the vnode cache by the path
  * first. If nothing is found, it reads the vnode from disk into the cache.
  */
-struct vnode *vfs_lookup_bypath(struct superblock *sb, char *path)
+struct vnode *vfs_lookup_bypath(struct tcb *task, char *path)
 {
-	/* If it's just / we already got it. */
+	/* If it's the root or current dir, we already got it. */
 	if (!strcmp(path, "/"))
-		return sb->root;
+		return task->rootdir;
+	if (!strcmp(path, "."))
+		return task->curdir;
 
 	/*
 	 * This does vfs cache + fs lookup.
 	 */
-	return generic_vnode_lookup(sb->root, path);
+	return generic_vnode_lookup(task->rootdir, path);
 }
 
 int vfs_mount_root(struct superblock *sb)
 {
-	/* Lookup the root vnode of this superblock */
-	vfs_root.pivot = vfs_lookup_bypath(sb, "/");
+	/* Lookup the root vnode of this superblock.
+	 * The root superblock has vnode number 0. */
+	vfs_root.pivot = vfs_lookup_byvnum(sb, 0);
 	vfs_root.sb = sb;
 
 	return 0;