From 3f9d6f0311088a389342371acb3168b45c7dece5 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Wed, 12 Apr 2023 17:53:02 +0300
Subject: [PATCH] LibC: add needed stubs to build executables with our compiler

---
 kernel/arch/i386/crt0.S    |  2 +-
 kernel/arch/x86_64/crt0.S  |  2 +-
 libc/include/stdio.h       |  3 +++
 libc/include/stdlib.h      |  1 +
 libc/include/sys/syscall.h |  3 +++
 libc/include/unistd.h      |  7 ++++---
 libc/stdlib.cpp            | 10 +++++++++-
 libc/unistd.cpp            | 35 +++++++++++++++++++++++++++++++++++
 8 files changed, 57 insertions(+), 6 deletions(-)
 create mode 100644 libc/include/sys/syscall.h

diff --git a/kernel/arch/i386/crt0.S b/kernel/arch/i386/crt0.S
index 127309fc..24453324 100644
--- a/kernel/arch/i386/crt0.S
+++ b/kernel/arch/i386/crt0.S
@@ -9,7 +9,7 @@ _start:
 	movl %esp, %ebp
 
 	# Prepare signals, memory allocation, stdio and such.
-	call initialize_standard_library
+	#call initialize_standard_library
 
 	# Run the global constructors.
 	call _init
diff --git a/kernel/arch/x86_64/crt0.S b/kernel/arch/x86_64/crt0.S
index bdc038e6..889e4983 100644
--- a/kernel/arch/x86_64/crt0.S
+++ b/kernel/arch/x86_64/crt0.S
@@ -13,7 +13,7 @@ _start:
 	pushq %rdi
 
 	# Prepare signals, memory allocation, stdio and such.
-	call initialize_standard_library
+	#call initialize_standard_library
 
 	# Run the global constructors.
 	call _init
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 107d4c16..c62de6a9 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -15,6 +15,9 @@
 #define SEEK_END 1
 #define SEEK_SET 2
 
+#define EXIT_FAILURE 1
+#define EXIT_SUCCESS 0
+
 __BEGIN_DECLS
 
 struct FILE;
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index e725f071..c0c7d3b8 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -6,6 +6,7 @@
 __BEGIN_DECLS
 
 [[noreturn]] void abort(void);
+[[noreturn]] void exit(int);
 
 int abs(int);
 
diff --git a/libc/include/sys/syscall.h b/libc/include/sys/syscall.h
new file mode 100644
index 00000000..767850e9
--- /dev/null
+++ b/libc/include/sys/syscall.h
@@ -0,0 +1,3 @@
+#pragma once
+
+#include <kernel/Syscall.h>
diff --git a/libc/include/unistd.h b/libc/include/unistd.h
index 3d908d5e..ef50a6ef 100644
--- a/libc/include/unistd.h
+++ b/libc/include/unistd.h
@@ -6,16 +6,17 @@
 #define STDOUT_FILENO 1
 #define STDERR_FILENO 2
 
-// fork(), execv(), execve(), execvp(), getpid()
-
 __BEGIN_DECLS
 
+[[noreturn]] void _exit(int);
+
 pid_t fork(void);
+pid_t getpid(void);
 
 int execv(const char*, char* const[]);
 int execve(const char*, char* const[], char* const[]);
 int execvp(const char*, char* const[]);
 
-pid_t getpid(void);
+long syscall(long, ...);
 
 __END_DECLS
\ No newline at end of file
diff --git a/libc/stdlib.cpp b/libc/stdlib.cpp
index 2824937d..b500d27f 100644
--- a/libc/stdlib.cpp
+++ b/libc/stdlib.cpp
@@ -1,10 +1,18 @@
+#include <BAN/Assert.h>
+#include <ctype.h>
 #include <stdlib.h>
 #include <string.h>
-#include <ctype.h>
+#include <unistd.h>
 
 void abort(void)
 {
+	ASSERT_NOT_REACHED();
+}
 
+void exit(int status)
+{
+	_exit(status);
+	ASSERT_NOT_REACHED();
 }
 
 int abs(int val)
diff --git a/libc/unistd.cpp b/libc/unistd.cpp
index 2383052a..d28197b6 100644
--- a/libc/unistd.cpp
+++ b/libc/unistd.cpp
@@ -1,5 +1,40 @@
+#include <BAN/Assert.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <sys/syscall.h>
 #include <unistd.h>
 
+void _exit(int status)
+{
+	syscall(SYS_EXIT, status);
+	ASSERT_NOT_REACHED();
+}
+
+long syscall(long syscall, ...)
+{
+	va_list args;
+	va_start(args, syscall);
+
+	long ret = 0;
+
+	switch (syscall)
+	{
+	case SYS_EXIT:
+		ret = Kernel::syscall(SYS_EXIT, va_arg(args, int));
+		break;
+	case SYS_READ:
+		ret = Kernel::syscall(SYS_READ, va_arg(args, int), va_arg(args, void*), va_arg(args, size_t));
+		break;
+	case SYS_WRITE:
+		ret = Kernel::syscall(SYS_WRITE, va_arg(args, int), va_arg(args, const void*), va_arg(args, size_t));
+		break;
+	}
+
+	va_end(args);
+	
+	return ret;
+}
+
 pid_t fork(void)
 {
 	return -1;