1 files changed, 188 insertions, 0 deletions
diff --git a/src/uapi/proc.c b/src/uapi/proc.c
new file mode 100644
index 0000000..e7fa49d
--- /dev/null
+++ b/src/uapi/proc.c
@@ -0,0 +1,188 @@
+/* SPDX-License-Identifier: copyleft-next-0.3.1 */
+/* Copyright 2021 - 2022, Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
+
+/**
+ * @file proc.c
+ * Process/thread handling syscall implementations.
+ */
+
+#include <kmi/elf.h>
+#include <kmi/uapi.h>
+#include <kmi/proc.h>
+#include <kmi/bits.h>
+#include <kmi/mem_regions.h>
+
+/**
+ * Create syscall handler.
+ *
+ * @param t Current tcb.
+ * @param func Function to jump to at thread creation.
+ * @param d0 Argument 0.
+ * @param d1 Argument 1.
+ * @param d2 Argument 2.
+ * @param d3 Argument 3.
+ *
+ * @return ERR_OOMEM if thread creation was unsuccessful, otherwise OK and the
+ * thread id.
+ */
+SYSCALL_DEFINE5(create)(struct tcb *t, sys_arg_t func,
+                        sys_arg_t d0, sys_arg_t d1, sys_arg_t d2, sys_arg_t d3)
+{
+	struct tcb *c = create_thread(t);
+	if (!c)
+		return_args1(t, ERR_OOMEM);
+
+	alloc_stack(c);
+
+	set_args5(c, c->tid, d0, d1, d2, d3);
+	set_return(c, func);
+
+	return_args2(t, OK, c->tid);
+}
+
+/**
+ * Fork syscall handler.
+ *
+ * \todo Not entirely sure how I should handle forks/execs etc, mostly whether I
+ * should allow forks/execs to be called directly or only though the process
+ * manager. Probably though the process manager, although that will add in a
+ * slight bit of delay.
+ *
+ * I suppose I could add in a runtime parameter
+ * that would allow them to be called directly, and then the process manager
+ * would have to periodically ask the kernel about all threads it is aware of
+ * via sys_sync. Dunno.
+ *
+ * @param t Current tcb.
+ * @return \ref OK and 0.
+ */
+SYSCALL_DEFINE0(fork)(struct tcb *t)
+{
+	struct tcb *c = get_cproc(t);
+	if (!(has_cap(c->caps, CAP_PROC)))
+		return_args1(t, ERR_PERM);
+
+	struct tcb *n = create_proc(get_eproc(t));
+	if (!n)
+		return_args1(t, ERR_OOMEM);
+
+	/* prepare args for when we eventually swap to the new proc, giving
+	 * parent ID as third return value */
+	set_args3(n, OK, 0, get_eproc(t)->pid);
+
+	return_args2(t, OK, n->pid);
+}
+
+/**
+ * Exec syscall handler.
+ *
+ * @param t Current tcb.
+ * @param bin Binary to execute.
+ * @param interp Optional interpreter binary.
+ *
+ * @return \see prepare_proc().
+ */
+SYSCALL_DEFINE2(exec)(struct tcb *t, sys_arg_t bin, sys_arg_t interp)
+{
+	/** @todo probably make sure thread is root thread of process? */
+	/* mark binary to be kept */
+	struct mem_region *b = find_used_region(&t->sp_r, bin);
+	if (!b)
+		return_args1(t, ERR_INVAL);
+
+	set_bit(b->flags, MR_KEEP);
+
+	struct mem_region *i = 0;
+	if (interp) {
+		/* mark interpreter to be kept */
+		i = find_used_region(&t->sp_r, interp);
+		if (!i)
+			return_args1(t, ERR_INVAL);
+
+		set_bit(i->flags, MR_KEEP);
+	}
+
+	/* free everything except regions to be kept */
+	clear_uvmem(t);
+
+	/* restore to normal */
+	clear_bit(b->flags, MR_KEEP);
+	if (interp)
+		clear_bit(b->flags, MR_KEEP);
+
+	return_args1(t, prepare_proc(t, bin, interp));
+}
+
+/**
+ * Spawn syscall handler.
+ *
+ * @param t Current tcb.
+ * @param bin Binary to execute.
+ * @param interp Optional interpreter binary.
+ *
+ * @return \see prepare_proc() and process id of the new process.
+ */
+SYSCALL_DEFINE2(spawn)(struct tcb *t, sys_arg_t bin, sys_arg_t interp)
+{
+	struct tcb *c = get_proc(t);
+	if (!(has_cap(c->caps, CAP_PROC)))
+		return_args1(t, ERR_PERM);
+
+	struct tcb *n = create_proc(NULL);
+	if (!n)
+		return_args1(t, ERR_OOMEM);
+
+	return_args2(t, prepare_proc(n, bin, interp), n->pid);
+}
+
+/**
+ * Kill syscall handler.
+ *
+ * @param t Current tcb.
+ * @param tid Thread to kill.
+ * \todo Implement.
+ *
+ * @return ERR_PERM if not capable to kill, otherwise OK.
+ */
+SYSCALL_DEFINE1(kill)(struct tcb *t, sys_arg_t tid)
+{
+	struct tcb *c = get_cproc(t);
+	if (!(has_cap(c->caps, CAP_PROC)))
+		return_args1(t, ERR_PERM);
+
+	/** @todo implement */
+	/** @todo remember to unregister IRQ handlers */
+
+	return_args1(t, OK);
+}
+
+/**
+ * Swap syscall handler.
+ *
+ * \todo Implement.
+ * \todo Should swap return the registers of the new thread that would be used
+ * for message passing?
+ *
+ * @param t Current tcb.
+ * @param tid Thread ID to swap to.
+ *
+ * @return \ref OK.
+ */
+SYSCALL_DEFINE1(swap)(struct tcb *t, sys_arg_t tid){
+	struct tcb *c = get_cproc(t);
+	if (!(has_cap(c->caps, CAP_PROC)))
+		return_args1(t, ERR_PERM);
+
+	struct tcb *s = get_tcb(tid);
+	if (!s)
+		return_args1(t, ERR_INVAL);
+
+	/* switch over to new thread */
+	use_tcb(s);
+
+	/* set return value for current thread */
+	set_args1(t, OK);
+
+	/* get register state for new thread */
+	return_args(s, get_args(s));
+}