kernel: replace await with wait2, roughly compatible with POSIX

dash works now :^)))

3 files changed, 44 insertions, 1 deletions

diff --git a/src/kernel/proc.c b/src/kernel/proc.c
index ecbd839..3ef35c0 100644
--- a/src/kernel/proc.c
+++ b/src/kernel/proc.c
@@ -349,7 +349,18 @@ void proc_tryreap(Proc *dead) {
 			if (parent->state != PS_WAITS4CHILDDEATH) {
 				return; /* don't reap yet */
 			}
-			regs_savereturn(&parent->regs, dead->death_msg);
+			if (parent->awaited_death.legacy) {
+				regs_savereturn(&parent->regs, dead->death_msg);
+			} else {
+				regs_savereturn(&parent->regs, proc_ns_id(parent->pns, dead));
+				if (parent->awaited_death.out) {
+					struct sys_wait2 __user *out = parent->awaited_death.out;
+					struct sys_wait2 data;
+					memset(&data, 0, sizeof data);
+					data.status = dead->death_msg;
+					pcpy_to(parent, out, &data, sizeof data);
+				}
+			}
 			proc_setstate(parent, PS_RUNNING);
 		}
 		/* can't be reaped anymore */
diff --git a/src/kernel/proc.h b/src/kernel/proc.h
index f473124..a1820dc 100644
--- a/src/kernel/proc.h
+++ b/src/kernel/proc.h
@@ -45,6 +45,10 @@ struct Proc {
 	union { /* saved value, meaning depends on .state */
 		int death_msg; // PS_DEAD
 		struct {
+			bool legacy; /* false = wait2, true = await */
+			struct sys_wait2 __user *out;
+		} awaited_death;
+		struct {
 			char __user *buf;
 			size_t max_len;
 			struct ufs_request __user *res;
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index 1e75f9d..66f8757 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -25,6 +25,7 @@ _Noreturn void _sys_exit(long ret) {
 long _sys_await(void) {
 	bool has_children = false;
 	proc_setstate(proc_cur, PS_WAITS4CHILDDEATH);
+	proc_cur->awaited_death.legacy = true;
 
 	for (Proc *iter = proc_cur->child;
 			iter; iter = iter->sibling)
@@ -401,6 +402,32 @@ uint32_t _sys_getppid(void) {
 	}
 }
 
+int _sys_wait2(int pid, int flags, struct sys_wait2 __user *out) {
+	if (pid != -1 || flags != 0) {
+		SYSCALL_RETURN(-ENOSYS);
+	}
+
+	bool has_children = false;
+	proc_setstate(proc_cur, PS_WAITS4CHILDDEATH);
+	proc_cur->awaited_death.legacy = false;
+	proc_cur->awaited_death.out = out;
+
+	for (Proc *iter = proc_cur->child; iter; iter = iter->sibling) {
+		if (iter->noreap) continue;
+		has_children = true;
+		if (iter->state == PS_TOREAP) {
+			proc_tryreap(iter);
+			return 0; // dummy
+		}
+	}
+
+	if (!has_children) {
+		proc_setstate(proc_cur, PS_RUNNING);
+		SYSCALL_RETURN(-ECHILD);
+	}
+	return 0; // dummy
+}
+
 long _sys_execbuf(void __user *ubuf, size_t len) {
 	if (len == 0) SYSCALL_RETURN(0);
 	if (len > EXECBUF_MAX_LEN)
@@ -455,6 +482,7 @@ long _syscall(long num, long a, long b, long c, long d, long e) {
 		break; case _SYS_INTR_SET:	_sys_intr_set((userptr_t)a);
 		break; case _SYS_GETPID:	_sys_getpid();
 		break; case _SYS_GETPPID:	_sys_getppid();
+		break; case _SYS_WAIT2:	_sys_wait2(a, b, (userptr_t)c);
 		break; case _SYS_EXECBUF:	_sys_execbuf((userptr_t)a, b);
 		break; case _SYS_DEBUG_KLOG:	_sys_debug_klog((userptr_t)a, b);
 		break;