Start work on filesystems.

9 files changed, 318 insertions, 64 deletions

diff --git a/src/kernel/Makefile b/src/kernel/Makefile
index 3fc7e9c..e847827 100644
--- a/src/kernel/Makefile
+++ b/src/kernel/Makefile
@@ -1,7 +1,8 @@
 
 OBJ = core/loader.o core/kmain.o core/dbglog.o core/sys.o \
 	core/gdt.o core/idt.o core/interrupt.o core/context_switch.o core/thread.o \
-	core/frame.o core/paging.o core/region.o core/kmalloc.o
+	core/frame.o core/paging.o core/region.o core/kmalloc.o \
+	user/vfs.o user/nullfs.o
 
 LIB = ../common/common.lib
 
diff --git a/src/kernel/core/kmain.c b/src/kernel/core/kmain.c
index 6024b77..2782cc1 100644
--- a/src/kernel/core/kmain.c
+++ b/src/kernel/core/kmain.c
@@ -13,6 +13,9 @@
 
 #include <thread.h>
 
+#include <vfs.h>
+#include <nullfs.h>
+
 #include <slab_alloc.h>
 #include <hashtbl.h>
 
@@ -150,23 +153,8 @@ void test_thread(void* a) {
 		if (i % 8 == 0) yield();
 	}
 }
-void kernel_init_stage2(void* data) {
-	dbg_print_region_info();
-	dbg_print_frame_stats();
-
-	test_hashtbl_1();
-	test_hashtbl_2();
-
-	thread_t *tb = new_thread(test_thread, 0);
-	resume_thread(tb, false);
 
-	for (int i = 0; i < 120; i++) {
-		dbg_printf("a");
-		for (int x = 0; x < 100000; x++) asm volatile("xor %%ebx, %%ebx":::"%ebx");
-	}
-	PANIC("Reached kmain end! Falling off the edge.");
-}
- 
+void kernel_init_stage2(void* data);
 void kmain(struct multiboot_info_t *mbd, int32_t mb_magic) {
 	dbglog_setup();
 
@@ -212,4 +200,33 @@ void kmain(struct multiboot_info_t *mbd, int32_t mb_magic) {
 	PANIC("Should never come here.");
 }
 
+void kernel_init_stage2(void* data) {
+	dbg_print_region_info();
+	dbg_print_frame_stats();
+
+	test_hashtbl_1();
+	test_hashtbl_2();
+
+	thread_t *tb = new_thread(test_thread, 0);
+	resume_thread(tb, false);
+
+	for (int i = 0; i < 120; i++) {
+		dbg_printf("a");
+		for (int x = 0; x < 100000; x++) asm volatile("xor %%ebx, %%ebx":::"%ebx");
+	}
+
+	register_nullfs_driver();
+	fs_t *devfs = make_fs("nullfs", 0, "");
+	ASSERT(devfs != 0);
+
+	//TODO :
+	// - populate devfs with information regarding kernel command line & modules
+	// - create user process with init module provided on command line
+	// - give it rights to devfs
+	// - launch it
+	// - just return, this thread is done
+
+	PANIC("Reached kmain end! Falling off the edge.");
+}
+
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/devfs.h b/src/kernel/include/devfs.h
new file mode 100644
index 0000000..0dee246
--- /dev/null
+++ b/src/kernel/include/devfs.h
@@ -0,0 +1,8 @@
+#pragma once
+
+#include <vfs.h>
+
+fs_t* init_devfs();
+
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/nullfs.h b/src/kernel/include/nullfs.h
new file mode 100644
index 0000000..16fff87
--- /dev/null
+++ b/src/kernel/include/nullfs.h
@@ -0,0 +1,25 @@
+#pragma once
+
+#include <vfs.h>
+
+#define NULLFS_OPT_CREATE_EN 		1
+#define NULLFS_OPT_DELETE_EN 		2
+
+typedef struct nullfs nullfs_t;
+
+typedef struct {
+	void* (*open)(void* f, int mode, fs_handle_t *h);
+	size_t (*read)(void* f, size_t offset, size_t len, char* buf);
+	size_t (*write)(void* f, size_t offset, size_t len, const char* buf);
+	void (*close)(void* f);
+	void (*delete)(void* f);
+} nullfs_node_ops_t;
+
+void register_nullfs_driver(); 
+
+nullfs_t* as_nullfs(fs_t *fs);
+
+bool nullfs_add(nullfs_t *f, const char* name, void* data, nullfs_node_ops_t* ops);
+bool nullfs_add_ram_file(nullfs_t *f, const char* name, void* data, size_t init_sz, int ok_modes);
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/process.h b/src/kernel/include/process.h
index 00ed1d7..a6ca1e9 100644
--- a/src/kernel/include/process.h
+++ b/src/kernel/include/process.h
@@ -3,41 +3,19 @@
 // Things described in this file are essentially a public interface
 // All implementation details are hidden in process.c
 
+// A process is a recipient for user code, as well as for mounting File Systems,
+// which allow access to features of the system.
+
 #include <thread.h>
 
 #include <hashtbl.h>
-#include <buffer.h>
-
-#define PW_NOT_WAITING		0
-#define PW_WAIT_ANY_MSG		1
-#define PW_WAIT_MSG_ON_CHAN	2
-
-#define PROCESS_MAILBOX_SIZE 42
-
-typedef int chan_id_t;
 
-typedef struct chan_pair {
-	chan_id_t fst, snd;
-} chan_pair_t;
-
-typedef struct message {
-	buffer_t *data;
-	chan_id_t chan_id;
-} message_t;
 
 struct process;
 typedef struct process process_t;
 
-process_t *new_process(entry_t entry, void* data, chan_pair_t *give_chans);
-
-chan_pair_t new_chan();		// not used very often, but still usefull
-chan_id_t unbox_chan(chan_id_t chan, chan_id_t subchan);
-void detach_chan(chan_id_t chan);		// chan ID is freed
-
-int send_message(chan_id_t chan, buffer_t *msg);	// nonnull on error (recipient queue is full)
+process_t *new_process(entry_t entry, void* data);
 
-size_t await_message();		// returns the size of the first message to come
-size_t await_message_on_chan(chan_id_t chan);		// returns the size of the first message to come
-message_t get_message();	// gets the first message in the queue (or nothing when queue is empty)
+bool mmap(process_t *proc, void* addr, size_t size, int type);
 
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/vfs.h b/src/kernel/include/vfs.h
new file mode 100644
index 0000000..5f7a0d8
--- /dev/null
+++ b/src/kernel/include/vfs.h
@@ -0,0 +1,86 @@
+#pragma once
+
+#include <stdbool.h>
+#include <malloc.h>
+
+typedef struct {
+	// TODO
+	// (should also be moved to a user-visible header)
+} stat_t;
+
+#define FM_READ 	(0x01)
+#define FM_WRITE 	(0x02)
+#define FM_MMAP 	(0x04)
+#define FM_CREATE   (0x10)
+#define FM_TRUNC    (0x20)
+#define FM_APPEND   (0x40)
+
+// How to use :
+// - when using a filesystem : never call the operations in fs_*_ops_t directly, use
+// 		the functions defined bellow
+// - when programming a filesystem : don't worry about allocating the fs_handle_t and fs_t,
+// 		it is done automatically
+
+
+// Structure defining a handle to an open file
+
+typedef struct {
+	size_t (*read)(void* f, size_t offset, size_t len, char* buf);
+	size_t (*write)(void* f, size_t offset, size_t len, const char* buf);
+	void (*close)(void* f);
+} fs_handle_ops_t;
+
+typedef struct fs_handle {
+	int refs;
+	fs_handle_ops_t *ops;
+	void* data;
+	int mode;
+} fs_handle_t;
+
+// Structure defining a filesystem
+
+typedef struct {
+	bool (*open)(void *fs, const char* file, int mode, fs_handle_t *s);
+	bool (*delete)(void *fs, const char* file);
+	bool (*rename)(void *fs, const char* from, const char* to);
+	bool (*stat)(void *fs, const char* file, stat_t *st);
+	int (*ioctl)(void *fs, const char* file, int command, void* data);
+	bool (*add_source)(void* fs, fs_handle_t* source);
+	void (*shutdown)(void *fs);
+} fs_ops_t;
+
+typedef struct fs {
+	int refs;
+	fs_ops_t *ops;
+	void* data;
+} fs_t;
+
+// Structure defining a filesystem driver
+
+typedef struct {
+	bool (*make)(fs_handle_t *source, char* opts, fs_t *d);
+	bool (*detect)(fs_handle_t *source);
+} fs_driver_ops_t;
+
+// Common functions
+
+void register_fs_driver(const char* name, fs_driver_ops_t *ops);
+
+fs_t* make_fs(const char* driver, fs_handle_t *source, char* opts);
+bool fs_add_source(fs_t *fs, fs_handle_t *source);
+void ref_fs(fs_t *fs);
+void unref_fs(fs_t *fs);
+
+bool fs_delete(fs_t *fs, const char* file);
+bool fs_rename(fs_t *fs, const char* from, const char* to);
+bool fs_stat(fs_t *fs, const char* file, stat_t *st);
+int fs_ioctl(fs_t *fs, const char* file, int command, void* data);
+
+fs_handle_t* fs_open(fs_t *fs, const char* file, int mode);
+void ref_file(fs_handle_t *file);
+void unref_file(fs_handle_t *file);
+size_t file_read(fs_handle_t *f, size_t offset, size_t len, char* buf);
+size_t file_write(fs_handle_t *f, size_t offset, size_t len, const char* buf);
+int file_get_mode(fs_handle_t *f);
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/user/nullfs.c b/src/kernel/user/nullfs.c
new file mode 100644
index 0000000..3c11198
--- /dev/null
+++ b/src/kernel/user/nullfs.c
@@ -0,0 +1,30 @@
+#include <nullfs.h>
+
+bool nullfs_i_make(fs_handle_t *source, char* opts, fs_t *d);
+
+fs_driver_ops_t nullfs_driver_ops = {
+	.make = nullfs_i_make,
+	.detect = 0,
+};
+
+fs_ops_t nullfs_ops = {
+	0 	//TODO
+};
+
+void register_nullfs_driver() {
+	register_fs_driver("nullfs", &nullfs_driver_ops);
+}
+
+nullfs_t *make_nullfs(char* options) {
+	fs_t *it = make_fs("nullfs", 0, options);
+	if (it == 0) return 0;
+	if (it->ops != &nullfs_ops) return 0;
+	return (nullfs_t*)it->data;
+}
+
+bool nullfs_i_make(fs_handle_t *source, char* opts, fs_t *d) {
+	// TODO
+	return false;
+}
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/user/process.c b/src/kernel/user/process.c
index 7519dae..22295ef 100644
--- a/src/kernel/user/process.c
+++ b/src/kernel/user/process.c
@@ -2,29 +2,12 @@
 #include <process.h>
 
 typedef struct process {
-	thread_t *thread;
-	int pid;
-
-	mutex_t com_mutex;
+	pagedir_t *pd;
 
-	hashtbl_t *chans;
-	chan_id_t next_chan_id;
-
-	message_t mbox[PROCESS_MAILBOX_SIZE];
-	int mbox_size;	// number of messages in queue
-	int mbox_first;	// first message in queue (circular buffer)
+	thread_t *thread;
 
-	// a process can be in several waiting states :
-	// - wait for any message
-	// - wait for a message on a particular channel
-	//   in this case, if a message is pushed on this particular channel,
-	//	 then it is put in front of the queue, so that it is the next message read
-	//	 (it is guaranteed that doing await_message_on_chan() immediately followed by get_message()
-	//   gets the message whose size was returned by await_...)
-	int wait_state;
-	chan_id_t wait_chan_id;		// when waiting for a message on a particular channel
+	int pid, ppid;
 } process_t;
 
-int push_message(process_t *proc, message_t msg);		// nonnull on error (process queue is full)
 
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/user/vfs.c b/src/kernel/user/vfs.c
new file mode 100644
index 0000000..ebd5808
--- /dev/null
+++ b/src/kernel/user/vfs.c
@@ -0,0 +1,126 @@
+#include <debug.h>
+#include <vfs.h>
+#include <string.h>
+
+// ============================= //
+// FILESYSTEM DRIVER REGISTERING //
+// ============================= //
+
+typedef struct fs_driver {
+	const char* name;
+	fs_driver_ops_t *ops;
+	struct fs_driver *next;
+} fs_driver_t;
+
+fs_driver_t *drivers = 0;
+
+void register_fs_driver(const char* name, fs_driver_ops_t *ops) {
+	fs_driver_t *d = (fs_driver_t*)malloc(sizeof(fs_driver_t));
+	ASSERT(d != 0); // should we fail in a more graceful manner ?
+
+	d->name = name;
+	d->ops = ops;
+	d->next = drivers;
+	drivers = d;
+}
+
+// ================================== //
+// CREATING AND DELETINF FILE SYSTEMS //
+// ================================== //
+
+fs_t *make_fs(const char* drv_name, fs_handle_t *source, char* opts) {
+	// Look for driver
+	fs_driver_t *d = 0;
+	for(fs_driver_t *i = drivers; i != 0; i = i->next) {
+		if (drv_name != 0 && strcmp(i->name, drv_name) == 0) d = i;
+		if (drv_name == 0 && source != 0 && i->ops->detect && i->ops->detect(source)) d = i;
+		if (d != 0) break;
+	}
+
+	// Open file system
+	fs_t *fs = (fs_t*)malloc(sizeof(fs_t));
+	if (fs == 0) return 0;
+
+	if (d->ops->make(source, opts, fs)) {
+		return fs;
+	} else {
+		free(fs);
+		return 0;
+	}
+}
+
+bool fs_add_source(fs_t *fs, fs_handle_t *source) {
+	return fs->ops->add_source && fs->ops->add_source(fs->data, source);
+}
+
+void ref_fs(fs_t *fs) {
+	fs->refs++;
+}
+
+void unref_fs(fs_t *fs) {
+	fs->refs--;
+	if (fs->refs == 0) {
+		fs->ops->shutdown(fs->data);
+		free(fs);
+	}
+}
+
+// DOING THINGS IN FLESYSTEMS //
+
+bool fs_delete(fs_t *fs, const char* file) {
+	return fs->ops->delete && fs->ops->delete(fs->data, file);
+}
+
+bool fs_rename(fs_t *fs, const char* from, const char* to) {
+	return fs->ops->rename && fs->ops->rename(fs->data, from, to);
+}
+
+bool fs_stat(fs_t *fs, const char* name, stat_t *st) {
+	return fs->ops->stat && fs->ops->stat(fs->data, name, st);
+}
+
+int fs_ioctl(fs_t *fs, const char* file, int command, void* data) {
+	return fs->ops->ioctl && fs->ops->ioctl(fs->data, file, command, data);
+}
+
+// =================== //
+// OPERATIONS ON FILES //
+// =================== //
+
+fs_handle_t* fs_open(fs_t *fs, const char* file, int mode) {
+	fs_handle_t *h = (fs_handle_t*)malloc(sizeof(fs_handle_t));
+	if (h == 0) return 0;
+
+	if (fs->ops->open(fs->data, file, mode, h)) {
+		return h;
+	} else {
+		free(h);
+		return 0;
+	}
+}
+
+void ref_file(fs_handle_t *file) {
+	file->refs++;
+}
+
+void unrefe_file(fs_handle_t *file) {
+	file->refs--;
+	if (file->refs == 0) {
+		file->ops->close(file->data);
+		free(file);
+	}
+}
+
+size_t file_read(fs_handle_t *f, size_t offset, size_t len, char* buf) {
+	return f->ops->read && f->ops->read(f->data, offset, len, buf);
+}
+
+size_t file_write(fs_handle_t *f, size_t offset, size_t len, const char* buf) {
+	return f->ops->write && f->ops->write(f->data, offset, len, buf);
+}
+
+int file_get_mode(fs_handle_t *f) {
+	return f->mode;
+}
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/