feat(proc): sync declarations and add docs

* Sync function and struct declarations with definitions
* Add documentation public facing functions

include/depthos/proc.h

@@ -25,6 +25,8 @@ typedef enum task_state {
 struct process {
   pid_t pid;
   char *filepath;
+  char const **argv;
+  char const **envp;
   process_state_t state;
   struct process *parent;
   struct list_entry *parent_entry;
@@ -67,32 +69,135 @@ struct task {
   struct fs_node **filetable;
 };
 
-struct process *process_spawn(const char *filepath, struct process *parent);
+
+/**
+ * @brief Spawn a process from the given parent process.
+ *
+ * @param filepath Executable file path (ELF).
+ * @param parent Parent process to link to.
+ * @param argv Arguments passed to the process.
+ * @param envp Environment variables passed to the process.
+ * @return struct process* Newly created process.
+ */
+struct process *process_spawn(const char *filepath, struct process *parent,
+                              char const **argv, char const **envp);
+/**
+ * @brief Kill a process with all it's threads and child processes.
+ */
 void process_kill(struct process *);
 
-struct task *create_task(void *entry, pagedir_t pgd, bool do_stack,
-                         void *stack);
-void bootstrap_user_task(struct task *task, bool do_stack, void *stack);
-void setup_task_filetable(struct fs_node *ft);
+/**
+ * @brief Create a task
+ *
+ * @param entry Address of the task entrypoint
+ * @param pgd Address space of the task (page directory)
+ * @param kernel Whether the task is executed with kernel privileges
+ * @param stack Base of the stack
+ * @param stack_size Size of task the stack
+ * @return struct task* Newly created task
+ */
+struct task *create_task(void *entry, pagedir_t pgd, bool kernel,
+                         uintptr_t stack, size_t stack_size);
+
+/**
+ * @brief Create a task with kernel privileges
+ *
+ * @param entry Address of the task entrypoint
+ * @param do_stack Whether to setup kernel stack for the task.
+ * @return struct task* Newly created task
+ */
 struct task *create_kernel_task(void *entry, bool do_stack);
-struct task *create_task_fork(struct task *original);
+
+/**
+ * @brief Fork the task
+ *
+ * @param original Task to fork.
+ * @return struct task* Forked task.
+ */
+struct task *fork_task(struct task *original);
+
+/**
+ * @brief Initialise kernel stack for a task.
+ *
+ * @param task Task to initialise stack for.
+ * @param esp Stack pointer.
+ */
+void task_init_kstack(struct task *task, uintptr_t esp);
+/*
+ * @brief Initialise kernel stack for a task with kernel privileges.
+ *
+ * @param task Task to initialise stack for.
+ * @param esp Stack pointer.
+ */
+void kernel_task_init_kstack(struct task *task, uintptr_t esp);
+
+/**
+ * @brief Initialise specified filetable.
+ *
+ * @param ft Filetable to initialise.
+ */
+void task_setup_filetable(struct fs_node **ft);
+/**
+ * @brief Create a thread in the current process.
+ *
+ * @param entry Address of the thread entrypoint.
+ * @param stack Thread stack base.
+ * @param pgd Address space of the thread (page directory)
+ * @param filetable Filetable to use for the thread.
+ * @return struct task* Newly created thread.
+ */
+struct task *thread_create(void *entry, void *stack, pagedir_t pgd,
+                           struct fs_node **filetable);
+/**
+ * @brief Destroy the specified thread.
+ *
+ * @param thread Thread to destroy.
+ */
+void thread_destroy(struct task *thread);
+
+/**
+ * @brief Reschedule to a particular task.
+ *
+ * @param next Task to reschedule to.
+ */
 void reschedule_to(struct task *next);
+
+/**
+ * @brief Reschedule to the next task in the queue
+ */
 void reschedule(void);
 
+/**
+ * @brief Add task to the scheduler queue.
+ *
+ */
 void sched_add(struct task *);
+/**
+ * @brief Remove the task from the scheduler queue.
+ *
+ * @param task Task to remove.
+ */
 void sched_remove(struct task *);
 void sched_init(void);
 
 void preempt_enable();
 void preempt_disable();
 
+/**
+ * @brief Task that is currently being executed.
+ *
+ */
 extern struct task *current_task;
 
 #define SC_CLONE_MEM 0x1
 struct sc_clone_params {
   int flags;
 };
 
+/**
+ * @brief Parameters of the sys_thcreate system call.
+ *
+ */
 struct sc_thcreate_params {
   int flags;
   bool join;