From b9102619393b4702a6fd32efab6e74c18e338753 Mon Sep 17 00:00:00 2001
From: Matthias Kruk <m@m10k.eu>
Date: Sun, 5 Jan 2020 16:50:48 +0900
Subject: [PATCH] Add process_get_sighandler() function

---
 kernel/core/process.c    | 48 +++++++++++++++++++++++++++++++++-------
 kernel/include/process.h |  2 ++
 2 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/kernel/core/process.c b/kernel/core/process.c
index 23335e2..3102317 100644
--- a/kernel/core/process.c
+++ b/kernel/core/process.c
@@ -497,7 +497,6 @@ int process_memcpy_ktop(process_t *proc, void *dst, void *src, u32_t bytes)
 {
 	int ret_val;
 
-	dbg_printf("pg_dir_memcpy(%p, %p, NULL, %p, 0x%08x)\n", proc, dst, src, bytes);
 	ret_val = pg_dir_memcpy(proc->p_pgdir, dst, NULL, src, bytes);
 
 	return(ret_val);
@@ -761,6 +760,7 @@ int process_signal_deliver(process_t *proc, int signal)
 				}
 			}
 		} else {
+			dbg_printf("Signal to current task\n");
 			/* handle the signal in the current task */
 			task = task_get_current();
 		}
@@ -779,16 +779,28 @@ int process_signal_deliver(process_t *proc, int signal)
 		 * we can use it without having to perform any translations. The usermode
 		 * stack will have to be translated though.
 		 */
-		vesp3 = (u32_t*)kstk->prevesp;
-		ret_val = _pg_dir_vpxlate((struct pagedir*)task->t_pgdir,
-								  (u32_t)vesp3, (u32_t*)&pesp3);
 
-		if(!ret_val) {
-			u32_t *parg0;
-			u32_t *peip;
+//		vesp3 = (u32_t*)kstk->prevesp;
+//		ret_val = _pg_dir_vpxlate((struct pagedir*)task->t_pgdir,
+//								  (u32_t)vesp3, (u32_t*)&pesp3);
 
-			/* push the signal number and the return address on the userspace stack */
+		if(!ret_val) {
+			/*
+			 * The stack frame for the signal handler should look something like this:
+			 *
+			 * | ... |
+			 * |-----|
+			 * | EIP |
+			 * | EBP |
+			 *
+			 *
+			 * We need space for two registers and the stack frame of the signal
+			 * handler. We will make use of process_memcpy_ktop() for simplicity's
+			 * sake.
+			 */
 
+			/* ...and just return from the interrupt. Done. */
+#if 0
 			/*
 			 * pesp3, pesp3 - 1, and pesp3 - 2 may not be on the same page, which would
 			 * be an atrociously hard-to-find bug.
@@ -837,6 +849,7 @@ int process_signal_deliver(process_t *proc, int signal)
 			 */
 			kstk->eip = (u32_t)proc->p_sighandler[signal];
 			kstk->prevesp -= (sizeof(kstk->prevesp) * 2);
+#endif /* 0 */
 		}
 
 		/* let the process continue execution */
@@ -857,24 +870,32 @@ cleanup:
  */
 static void _sig_term(int sig)
 {
+	debug(__func__, strlen(__func__));
+
 	_exit(sig);
 	return;
 }
 
 static void _sig_ign(int sig)
 {
+	debug(__func__, strlen(__func__));
+
 	/* do nothing */
 	return;
 }
 
 static void _sig_core(int sig)
 {
+	debug(__func__, strlen(__func__));
+
 	_exit(sig);
 	return;
 }
 
 static void _sig_stop(int sig)
 {
+	debug(__func__, strlen(__func__));
+
 	/*
 	 * FIXME: Stop the process
 	 *  - Change the process state
@@ -889,6 +910,8 @@ static void _sig_stop(int sig)
 
 static void _sig_cont(int sig)
 {
+	debug(__func__, strlen(__func__));
+
 	/*
 	 * FIXME: Continue the process
 	 *  - Change its state back to a runnable state
@@ -1012,3 +1035,12 @@ int process_task_foreach(process_t *proc, int (*func)(process_t*, task_t*, void*
 
 	return(ret_val);
 }
+
+void* process_get_sighandler(process_t *proc, int signal)
+{
+	if(signal < 0 || signal > SIGMAX) {
+		return(NULL);
+	}
+
+	return((void*)proc->p_sighandler[signal]);
+}
diff --git a/kernel/include/process.h b/kernel/include/process.h
index c249709..ce2a108 100644
--- a/kernel/include/process.h
+++ b/kernel/include/process.h
@@ -48,6 +48,8 @@ int           process_wait(pid_t);
 int           process_signal(pid_t);
 int           process_signal_deliver(process_t*, int);
 
+void*         process_get_sighandler(process_t*, int);
+
 void*         process_get_tasks(process_t*);
 pid_t         process_get_id(process_t*);
 int           process_exit(process_t*, int);
-- 
2.47.3