devman and vfs: check if a function is not implemented before calling

src/fs/devfs.c

@@ -45,10 +45,6 @@ static int devfs_open(dirnode_t* parent, char* name){
 }
 
 static int devfs_close(){return 0;}
-static int devfs_mkdir() UNIMPLEMENTED
-static int devfs_create() UNIMPLEMENTED
-static int devfs_write() UNIMPLEMENTED
-static int devfs_read() UNIMPLEMENTED
 
 static int devfs_getdirent(dirnode_t* node, dent_t* buff, size_t count, uintmax_t offset, size_t* readcount){
 
@@ -84,7 +80,7 @@ static int devfs_chmod(vnode_t* node, mode_t mode){
 }
 
 static fscalls_t devfscalls = {
-	devfs_mount, devfs_unmount, devfs_open, devfs_close, devfs_mkdir, devfs_create, devfs_write, devfs_read, devfs_getdirent, devfs_chmod
+	devfs_mount, devfs_unmount, devfs_open, devfs_close, NULL, NULL, NULL, NULL, devfs_getdirent, devfs_chmod
 };
 
 void devfs_init(){

src/fs/vfs.c

@@ -87,7 +87,9 @@ int vfs_write(int* error, vnode_t* node, void* buff, size_t count, size_t offset
 		
 		return writecount;
 	}
-
+	
+	if(!node->fs->calls->write)
+		return ENOSYS;
 	
 	spinlock_acquire(&lock);
 	
@@ -156,7 +158,6 @@ int vfs_read(int* error, vnode_t* node, void* buff, size_t count, size_t offset,
 	if(!fd)
 		fd = &tmpfd;
 
-
 	int type = GETTYPE(node->st.st_mode);
 	
 	if(type == TYPE_SOCKET)
@@ -175,6 +176,9 @@ int vfs_read(int* error, vnode_t* node, void* buff, size_t count, size_t offset,
 		int readcount = devman_read(error, node->st.st_rdev, buff, count, offset);
 		return readcount;
 	}
+
+	if(!node->fs->calls->read)
+		return ENOSYS;
 	
 	spinlock_acquire(&lock);
 	
@@ -187,6 +191,9 @@ int vfs_read(int* error, vnode_t* node, void* buff, size_t count, size_t offset,
 }
 
 int vfs_close(vnode_t* node){
+	
+	if(!node->fs->calls->close)
+		return ENOSYS;
 		
 	spinlock_acquire(&lock);
 	
@@ -207,6 +214,9 @@ int vfs_close(vnode_t* node){
 int vfs_getdirent(dirnode_t* node, dent_t* buff, size_t count, uintmax_t offset, size_t* readcount){
 	
 	int err = 0;
+	
+	if(!node->vnode.fs->calls->getdirent)
+		return ENOSYS;
 
 	spinlock_acquire(&lock);
 	
@@ -295,6 +305,11 @@ int vfs_create(dirnode_t* ref, char* path, mode_t mode){
 		spinlock_release(&lock);
 		return result;
 	}
+	
+	if(!parent->vnode.fs->calls->create){
+		spinlock_release(&lock);
+		return ENOSYS;
+	}
 
 	result = parent->vnode.fs->calls->create(parent, name, mode);