Add kernel task manager, task list command, and async exec scheduling

Author: pradosh-arduino

source/includes/commands/commands.h

@@ -38,5 +38,6 @@ int cmd_mount(int argc, char** argv);
 int cmd_mv(int argc, char** argv);
 int cmd_umount(int argc, char** argv);
 int cmd_exec(int argc, char** argv);
+int cmd_tasks(int argc, char** argv);
 
 #endif

source/includes/multitasking.h

@@ -0,0 +1,55 @@
+#ifndef MULTITASKING_H
+#define MULTITASKING_H
+
+#include <basics.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef enum {
+    TASK_TYPE_KERNEL = 0,
+    TASK_TYPE_USERLAND = 1
+} task_type_t;
+
+typedef enum {
+    TASK_STATE_READY = 0,
+    TASK_STATE_RUNNING = 1,
+    TASK_STATE_EXITED = 2
+} task_state_t;
+
+typedef struct task_info {
+    uint32_t pid;
+    task_type_t type;
+    task_state_t state;
+    int exit_code;
+    uint64_t runtime_ticks;
+    const char* name;
+} task_info_t;
+
+typedef struct user_task_spec {
+    const char* path;
+    int argc;
+    const char* argv[32];
+} user_task_spec_t;
+
+typedef bool (*task_iter_cb_t)(const task_info_t* info, void* ctx);
+typedef bool (*kernel_task_fn_t)(uint32_t pid, uint64_t now_ticks, void* ctx, int* exit_code);
+
+void multitasking_init(void);
+void multitasking_on_pit_tick(uint64_t now_ticks);
+void multitasking_pump(void);
+
+uint32_t multitasking_spawn_kernel(const char* name, kernel_task_fn_t fn, void* ctx);
+uint32_t multitasking_spawn_userland(const char* name, const user_task_spec_t* spec);
+
+bool multitasking_exit_task(uint32_t pid, int exit_code);
+bool multitasking_get_task(uint32_t pid, task_info_t* out_info);
+uint32_t multitasking_current_pid(void);
+
+uint32_t multitasking_count_tasks(void);
+uint32_t multitasking_count_running(void);
+
+bool multitasking_for_each_task(task_iter_cb_t cb, void* ctx);
+
+void multitasking_start_cursor_blink_task(void);
+
+#endif

source/kernel/C/kernel.c

@@ -15,6 +15,7 @@
 #include <kernel.h>
 #include <tty.h>
 #include <executables/elf.h>
+#include <multitasking.h>
 
 int terminal_rows = 0;
 int terminal_columns = 0;
@@ -245,6 +246,8 @@ void main(void) {
     init_hashing();
 
     mm_print_out();
+    multitasking_init();
+    multitasking_start_cursor_blink_task();
     create_user_str("root", "prad");
 
     wm_addr = module_request.response->modules[0]->address;