Organize system calls

* syscalls should all return j6_status_t now
* syscalls are grouped by category in name as well as in files

src/kernel/syscalls/process.cpp

@@ -0,0 +1,93 @@
+#include "j6/errors.h"
+#include "j6/types.h"
+
+#include "log.h"
+#include "scheduler.h"
+
+namespace syscalls {
+
+j6_status_t
+process_exit(int64_t status)
+{
+	auto &s = scheduler::get();
+	auto *p = s.current();
+	log::debug(logs::syscall, "Process %d exiting with code %d", p->pid, status);
+
+	p->exit(status);
+	s.schedule();
+
+	log::error(logs::syscall, "returned to exit syscall");
+	return j6_err_unexpected;
+}
+
+j6_status_t
+process_fork(pid_t *pid)
+{
+	if (pid == nullptr) {
+		return j6_err_invalid_arg;
+	}
+
+	auto &s = scheduler::get();
+	auto *p = s.current();
+	pid_t ppid = p->pid;
+
+	log::debug(logs::syscall, "Process %d calling fork(%016llx)", ppid, pid);
+
+	*pid = p->fork();
+
+	p = s.current();
+	log::debug(logs::syscall, "Process %d's fork: returning %d from process %d", ppid, *pid, p->pid);
+
+	return j6_status_ok;
+}
+
+j6_status_t
+process_getpid(pid_t *pid)
+{
+	if (pid == nullptr) {
+		return j6_err_invalid_arg;
+	}
+
+	auto &s = scheduler::get();
+	auto *p = s.current();
+
+	*pid = p->pid;
+	return j6_status_ok;
+}
+
+j6_status_t
+process_log(const char *message)
+{
+	if (message == nullptr) {
+		return j6_err_invalid_arg;
+	}
+
+	auto &s = scheduler::get();
+	auto *p = s.current();
+	log::info(logs::syscall, "Message[%d]: %s", p->pid, message);
+	return j6_status_ok;
+}
+
+j6_status_t
+process_pause()
+{
+	auto &s = scheduler::get();
+	auto *p = s.current();
+	p->wait_on_signal(-1ull);
+	s.schedule();
+	return j6_status_ok;
+}
+
+j6_status_t
+process_sleep(uint64_t til)
+{
+	auto &s = scheduler::get();
+	auto *p = s.current();
+	log::debug(logs::syscall, "Process %d sleeping until %d", p->pid, til);
+
+	p->wait_on_time(til);
+	s.schedule();
+	return j6_status_ok;
+}
+
+} // namespace syscalls