Symlinks that point to a directory can now be mounted.

Tidied the code a bit.

2 files changed, 100 insertions, 16 deletions

diff --git a/arch/um/fs/hostfs/hostfs_kern.c b/arch/um/fs/hostfs/hostfs_kern.c
index b678922..2b63356 100644
--- a/arch/um/fs/hostfs/hostfs_kern.c
+++ b/arch/um/fs/hostfs/hostfs_kern.c
@@ -104,23 +104,87 @@ static int read_name(struct inode *ino, char *name)
 	return(0);
 }
 
+static char *follow_link(char *link)
+{
+	int len, n;
+	char *name, *resolved, *end;
+
+	len = 64;
+	while(1){
+		n = -ENOMEM;
+		name = kmalloc(len, GFP_KERNEL);
+		if(name == NULL)
+			goto out;
+
+		n = do_readlink(link, name, len);
+		if(n < len)
+			break;
+		len *= 2;
+		kfree(name);
+	}
+	if(n < 0)
+		goto out_free;
+
+	if(*name == '/')
+		return(name);
+
+	end = strrchr(link, '/');
+	if(end == NULL)
+		return(name);
+
+	*(end + 1) = '\0';
+	len = strlen(link) + strlen(name) + 1;
+
+	resolved = kmalloc(len, GFP_KERNEL);
+	if(resolved == NULL){
+		n = -ENOMEM;
+		goto out_free;
+	}
+
+	sprintf(resolved, "%s%s", link, name);
+	kfree(name);
+	kfree(link);
+	return(resolved);
+
+ out_free:
+	kfree(name);
+ out:
+	return(ERR_PTR(n));
+}
+
 static int read_inode(struct inode *ino)
 {
 	char *name;
 	int err;
 
+	err = -ENOMEM;
 	name = inode_name(ino, 0);
-	if(name == NULL) return(-ENOMEM);
+	if(name == NULL) 
+		goto out;
+
+	if(file_type(name, NULL) == OS_TYPE_SYMLINK){
+		name = follow_link(name);
+		if(IS_ERR(name)){
+			err = PTR_ERR(name);
+			goto out;
+		}
+	}
+	
 	err = read_name(ino, name);
 	kfree(name);
+ out:
 	return(err);
 }
 
 void hostfs_delete_inode(struct inode *ino)
 {
-	if(ino->u.hostfs_i.host_filename) kfree(ino->u.hostfs_i.host_filename);
+	if(ino->u.hostfs_i.host_filename) 
+		kfree(ino->u.hostfs_i.host_filename);
 	ino->u.hostfs_i.host_filename = NULL;
-	if(ino->u.hostfs_i.fd != -1) close_file(&ino->u.hostfs_i.fd);
+
+	if(ino->u.hostfs_i.fd != -1) 
+		close_file(&ino->u.hostfs_i.fd);
+
 	ino->u.hostfs_i.mode = 0;
 	clear_inode(ino);
 }
@@ -187,22 +251,34 @@ int hostfs_file_open(struct inode *ino, struct file *file)
 	int mode = 0, r = 0, w = 0, fd;
 
 	mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
-	if((mode & ino->u.hostfs_i.mode) == mode) return(0);
+	if((mode & ino->u.hostfs_i.mode) == mode)
+		return(0);
 
+	/* The file may already have been opened, but with the wrong access,
+	 * so this resets things and reopens the file with the new access.
+	 */
 	if(ino->u.hostfs_i.fd != -1){
 		close_file(&ino->u.hostfs_i.fd);
 		ino->u.hostfs_i.fd = -1;
 	}
+
 	ino->u.hostfs_i.mode |= mode;
-	if(ino->u.hostfs_i.mode & FMODE_READ) r = 1;
-	if(ino->u.hostfs_i.mode & FMODE_WRITE) w = 1;
-	if(w) r = 1;
+	if(ino->u.hostfs_i.mode & FMODE_READ) 
+		r = 1;
+	if(ino->u.hostfs_i.mode & FMODE_WRITE) 
+		w = 1;
+	if(w) 
+		r = 1;
+
 	name = dentry_name(file->f_dentry, 0);
-	if(name == NULL) return(-ENOMEM);
+	if(name == NULL) 
+		return(-ENOMEM);
+
 	fd = open_file(name, r, w);
 	kfree(name);
 	if(fd < 0) return(fd);
 	file_hostfs_i(file)->fd = fd;
+
 	return(0);
 }
 
@@ -712,10 +788,13 @@ int hostfs_link_readpage(struct file *file, struct page *page)
 	if(name == NULL) return(-ENOMEM);
 	err = do_readlink(name, buffer, PAGE_CACHE_SIZE);
 	kfree(name);
-	if(err == 0){
+	if(err == PAGE_CACHE_SIZE)
+		err = -E2BIG;
+	else if(err > 0){
 		flush_dcache_page(page);
 		SetPageUptodate(page);
 		if (PageError(page)) ClearPageError(page);
+		err = 0;
 	}
 	kunmap(page);
 	UnlockPage(page);
diff --git a/arch/um/fs/hostfs/hostfs_user.c b/arch/um/fs/hostfs/hostfs_user.c
index a81f3e9..97e40ac 100644
--- a/arch/um/fs/hostfs/hostfs_user.c
+++ b/arch/um/fs/hostfs/hostfs_user.c
@@ -50,8 +50,11 @@ int file_type(const char *path, int *rdev)
 {
  	struct stat64 buf;
 
-	if(lstat64(path, &buf) < 0) return(-errno);
-	*rdev = buf.st_rdev;
+	if(lstat64(path, &buf) < 0) 
+		return(-errno);
+	if(rdev != NULL) 
+		*rdev = buf.st_rdev;
+
 	if(S_ISDIR(buf.st_mode)) return(OS_TYPE_DIR);
 	else if(S_ISLNK(buf.st_mode)) return(OS_TYPE_SYMLINK);
 	else if(S_ISCHR(buf.st_mode)) return(OS_TYPE_CHARDEV);
@@ -277,12 +280,14 @@ int link_file(const char *to, const char *from)
 
 int do_readlink(char *file, char *buf, int size)
 {
-	int err;
+	int n;
 
-	err = readlink(file, buf, size);
-	if(err < 0) return(-errno);
-	if(err < size) buf[err] = '\0';
-	return(0);	
+	n = readlink(file, buf, size);
+	if(n < 0) 
+		return(-errno);
+	if(n < size) 
+		buf[n] = '\0';
+	return(n);
 }
 
 int rename_file(char *from, char *to)