VFS mount/umount + sys_open/close/read/fake write

include/config.h

@@ -28,6 +28,7 @@
 #define PROCESS_NAME_MAX 64
 #define PROCESS_STACK_SIZE 0x10000 // 64kb
 #define PROCESS_STACK_TOP 0x80000000
+#define PROCESS_FD_MAX 32
 
 /* sched */
 // 1 tick = 1 ms => quantum = 10ms
@@ -47,6 +48,7 @@
 
 /* fs */
 #define CALYXFS_FILES_MAX 10
+#define TAR_OPEN_FILES_MAX 64
 
 /* paging */
 #define PAGING_MAX_PHYS 0x200000000

include/fs/tar.h

@@ -9,6 +9,7 @@
 
 #include <stdint.h>
 #include <limine.h>
+#include <stddef.h>
 
 struct tar_header
 {
@@ -33,4 +34,9 @@ int tar_init_fs(struct limine_file* file);
 struct tar_header* tar_file_lookup(const char* filename);
 void tar_file_read(struct tar_header* header, uint8_t* buf);
 
+int tar_open(const char* path, int flags);
+int tar_close(int fd);
+int64_t tar_read(int fd, char* buf, size_t count);
+int64_t tar_write(int fd, char* buf, size_t count);
+
 #endif

include/fs/vfs.h

@@ -0,0 +1,50 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Virtual filesystem layer
+ * @license GPL-3.0-only
+ */
+
+/*
+ PepperOS will not work like the Unix-based mountpoint approach,
+ but rather like what Windows does. Filesystems will be separated
+ into "drives", and each drive will have a number assigned.
+ */
+
+#ifndef VFS_H
+#define VFS_H
+
+#include <limine.h>
+#include <stddef.h>
+#include <stdint.h>
+
+typedef enum
+{
+    DRIVE_TAR
+} DriveType;
+
+struct drive
+{
+    unsigned int id;
+    DriveType type;
+    struct fs_operations* operations;
+
+    struct drive* next;
+};
+
+struct fs_operations
+{
+    int (*open)(const char* path, int flags);
+    int (*close)(int fd);
+    int64_t (*read)(int fd, char* buf, size_t count);
+    int64_t (*write)(int fd, char* buf, size_t count);
+};
+
+int vfs_mount(struct limine_file* file, DriveType type);
+int vfs_umount(unsigned int drive_id);
+
+int vfs_open(const char* path, int flags);
+int vfs_close(int fd);
+int64_t vfs_read(int fd, char* buf, size_t count);
+int64_t vfs_write(int fd, const char* buf, size_t count);
+
+#endif

include/kernel.h

@@ -10,7 +10,13 @@
 #include "limine.h"
 enum ErrorCodes {
 	ENOMEM,
-	EIO
+	EIO,
+	EINVAL,
+	ENOENT,
+	EFAULT,
+	EBADF,
+	EBUSY,
+	ENOSYS
 };
 
 #define CLEAR_INTERRUPTS __asm__ volatile("cli")

include/sched/process.h

@@ -11,6 +11,7 @@
 #include <config.h>
 #include <stdint.h>
 #include <limine.h>
+#include <stdbool.h>
 
 typedef enum {
     READY,
@@ -18,6 +19,12 @@ typedef enum {
     DEAD
 } status_t;
 
+struct process_fd {
+    bool used;
+    unsigned int drive_id;
+    int fs_fd;
+};
+
 struct process {
     size_t pid;
     char name[PROCESS_NAME_MAX];
@@ -26,6 +33,7 @@ struct process {
     struct cpu_status* context;
 	void* root_page_table; // Process PML4 (should contain kernel PML4 in higher half [256-511]
     void* kernel_stack; // Used for interrupts (syscall: int 0x80), defines the TSS RSP0
+    struct process_fd fds[PROCESS_FD_MAX];
     struct process* next;
 };
 
@@ -40,4 +48,9 @@ void process_display_list(struct process* processes_list);
 
 void process_create_user(struct limine_file* file, char* name);
 
+void process_fd_init(struct process* proc);
+int process_fd_alloc(struct process* proc, unsigned int drive_id, int fs_fd);
+int process_fd_get_fsfd(struct process* proc, int fd, unsigned int* drive_id, int* fs_fd);
+int process_fd_release(struct process* proc, int fd);
+
 #endif