From cbb9f47ee52a866e986ce954a2ceead49d0a046b Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Sun, 4 Jun 2023 17:59:13 +0300
Subject: [PATCH] LibC: add wait and waitpid

Note that wait() doesn't work since only waiting for specified
pid is supported. wait() will just return -1 and set errno to
ECHILD.
---
 libc/CMakeLists.txt        |  1 +
 libc/include/sys/syscall.h |  1 +
 libc/include/sys/wait.h    |  5 +++--
 libc/sys/wait.cpp          | 13 +++++++++++++
 libc/unistd.cpp            |  8 ++++++++
 5 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 libc/sys/wait.cpp

diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index c42271df..14eee1c2 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -10,6 +10,7 @@ set(LIBC_SOURCES
 	stdio.cpp
 	stdlib.cpp
 	string.cpp
+	sys/wait.cpp
 	termios.cpp
 	unistd.cpp
 	math.S
diff --git a/libc/include/sys/syscall.h b/libc/include/sys/syscall.h
index 3cb1af42..6a04fb2d 100644
--- a/libc/include/sys/syscall.h
+++ b/libc/include/sys/syscall.h
@@ -21,6 +21,7 @@ __BEGIN_DECLS
 #define SYS_SLEEP 14
 #define SYS_EXEC 15
 #define SYS_REALLOC 16
+#define SYS_WAIT 17
 
 __END_DECLS
 
diff --git a/libc/include/sys/wait.h b/libc/include/sys/wait.h
index 0a9a82ff..c5d95f19 100644
--- a/libc/include/sys/wait.h
+++ b/libc/include/sys/wait.h
@@ -20,11 +20,12 @@ __BEGIN_DECLS
 #define WNOWAIT		0x10
 #define WSTOPPED	0x20
 
+#define WEXITSTATUS(status)	(status & 0xFF)
+#define WIFEXITED(status)	(WEXITSTATUS(status) != 0)
+
 // FIXME
 #if 0
-#define WEXITSTATUS
 #define WIFCONTINUED
-#define WIFEXITED
 #define WIFSIGNALED
 #define WIFSTOPPED
 #define WSTOPSIG
diff --git a/libc/sys/wait.cpp b/libc/sys/wait.cpp
new file mode 100644
index 00000000..7e85bd50
--- /dev/null
+++ b/libc/sys/wait.cpp
@@ -0,0 +1,13 @@
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+pid_t wait(int* stat_loc)
+{
+	return waitpid(-1, stat_loc, 0);
+}
+
+pid_t waitpid(pid_t pid, int* stat_loc, int options)
+{
+	return (pid_t)syscall(SYS_WAIT, pid, stat_loc, options);
+}
\ No newline at end of file
diff --git a/libc/unistd.cpp b/libc/unistd.cpp
index 4818b6d3..81df889c 100644
--- a/libc/unistd.cpp
+++ b/libc/unistd.cpp
@@ -137,6 +137,14 @@ long syscall(long syscall, ...)
 			ret = Kernel::syscall(SYS_REALLOC, (uintptr_t)ptr, size);
 			break;
 		}
+		case SYS_WAIT:
+		{
+			pid_t pid = va_arg(args, pid_t);
+			int* stat_loc = va_arg(args, int*);
+			int options = va_arg(args, int);
+			ret = Kernel::syscall(SYS_WAIT, pid, (uintptr_t)stat_loc, options);
+			break;
+		}
 		default:
 			puts("LibC: Unhandeled syscall");
 			ret = -ENOSYS;