From a6557ed0233e2193cef0ab5b4cea7f1d7f19ad5d Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Thu, 4 Jul 2024 23:40:37 +0300
Subject: use notification framework for orphanizing threads

---
 src/uapi/ipc.c  | 15 +++++++++------
 src/uapi/proc.c | 26 ++++++++++++++++++--------
 2 files changed, 27 insertions(+), 14 deletions(-)

(limited to 'src/uapi')

diff --git a/src/uapi/ipc.c b/src/uapi/ipc.c
index bc49dbb..ddc7242 100644
--- a/src/uapi/ipc.c
+++ b/src/uapi/ipc.c
@@ -138,8 +138,8 @@ static bool __enough_rpc_stack(struct tcb *t)
 /**
  * Actually run notification handler, no ifs or buts.
  *
- * @param t Previous thread.
- * @param r Next thread.
+ * @param t Current thread.
+ * @param r Process where notification handler is.
  *
  * \p t and \p r may be the same thread.
  */
@@ -148,12 +148,15 @@ static __noreturn void __run_notify(struct tcb *t, struct tcb *r)
 	use_tcb(r);
 
 	enum sys_user code = SYS_USER_NOTIFY;
-	/* if we're not in RPC, we can safely notify of a signal while we're at
-	 * it */
-	enum notify_flag flags = is_rpc(t) ? 0 : NOTIFY_SIGNAL;
+	enum notify_flag flags = 0;
+
+	/* if we're in the root process, we can safely handle signals and
+	 * becoming orphaned */
+	if (!is_rpc(t))
+		set_bits(flags, t->notify_flags & (NOTIFY_SIGNAL | NOTIFY_ORPHANED));
 
 	/* handle critical notifications with special care */
-	if (is_set(flags, NOTIFY_IRQ | NOTIFY_TIMER)) {
+	if (is_set(t->notify_flags, NOTIFY_IRQ | NOTIFY_TIMER)) {
 		set_bits(flags, t->notify_flags & (NOTIFY_IRQ | NOTIFY_TIMER));
 		disable_irqs();
 	}
diff --git a/src/uapi/proc.c b/src/uapi/proc.c
index 231cc32..5b64dce 100644
--- a/src/uapi/proc.c
+++ b/src/uapi/proc.c
@@ -92,10 +92,17 @@ SYSCALL_DEFINE0(fork)(struct tcb *t)
 SYSCALL_DEFINE2(exec)(struct tcb *t, sys_arg_t bin, sys_arg_t interp)
 {
 	/** @todo probably make sure thread is root thread of process? */
+	if (!is_proc(t))
+		return_args1(t, ERR_PERM);
+
+	/* exec is only allowed if we own all our own resources */
+	if (t->refcount)
+		return_args1(t, ERR_INVAL)
+
 	/* mark binary to be kept */
 	struct mem_region *b = find_used_region(&t->sp_r, bin);
 	if (!b)
-		return_args1(t, ERR_INVAL);
+		return_args1(t, ERR_ADDR);
 
 	set_bit(b->flags, MR_KEEP);
 
@@ -237,28 +244,31 @@ SYSCALL_DEFINE1(exit)(struct tcb *t, sys_arg_t tid)
 /**
  * Syscall handler for orphanizing a thread.
  *
- * @param t Thread that wants to make itself an orphant.
+ * @param t Current thread.
+ * @param tid Thread we want to orphanize. May be ourselves.
  * @return \ref OK on success,
  * \ref ERR_PERM if current process missing \ref CAP_PROC,
  * \ref ERR_INVAL if already an orphant.
  */
-SYSCALL_DEFINE0(detach)(struct tcb *t)
+SYSCALL_DEFINE1(detach)(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);
 
-	if (orphan(t))
+	struct tcb *o = get_tcb(tid);
+	if (!o || orphan(o))
 		return_args1(t, ERR_INVAL);
 
-	struct tcb *r = get_tcb(t->rid);
+	struct tcb *r = get_tcb(o->rid);
 	if (r)
 		unreference_proc(r);
 
-	orphanize(t);
+	orphanize(o);
 
-	if (!is_rpc(t))
-		unorphanize(t);
+	/* generally the thread shouldn't do anything with this information, but
+	 * it fits really nicely into the notification framework so just do it */
+	notify(o, NOTIFY_ORPHANED);
 
 	return_args1(t, OK);
 }
-- 
cgit v1.3