From 896b919c9d00d568443f42da39cae83dd4eca6fb Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Mon, 5 Jun 2023 20:34:08 +0300
Subject: [PATCH] Kernel/LibC: pass environ pointer to process

---
 kernel/arch/x86_64/Thread.S     | 3 ++-
 kernel/arch/x86_64/crt0.S       | 3 +++
 kernel/include/kernel/Process.h | 3 ++-
 kernel/kernel/Process.cpp       | 1 +
 kernel/kernel/Thread.cpp        | 4 ++--
 libc/unistd.cpp                 | 5 ++++-
 6 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/kernel/arch/x86_64/Thread.S b/kernel/arch/x86_64/Thread.S
index 3a5a934e90..e5c55ff6ee 100644
--- a/kernel/arch/x86_64/Thread.S
+++ b/kernel/arch/x86_64/Thread.S
@@ -25,7 +25,7 @@ continue_thread:
 	movq $0, %rax
 	jmp *%rsi
 
-# void thread_userspace_trampoline(uint64_t rsp, uint64_t rip, int argc, char** argv)
+# void thread_userspace_trampoline(uint64_t rsp, uint64_t rip, int argc, char** argv, char** envp)
 .global thread_userspace_trampoline
 thread_userspace_trampoline:
 	pushq $0x23
@@ -35,4 +35,5 @@ thread_userspace_trampoline:
 	pushq %rsi
 	movq %rdx, %rdi
 	movq %rcx, %rsi
+	movq %r8, %rdx
 	iretq
diff --git a/kernel/arch/x86_64/crt0.S b/kernel/arch/x86_64/crt0.S
index 1f0832603d..dc3fdffc7d 100644
--- a/kernel/arch/x86_64/crt0.S
+++ b/kernel/arch/x86_64/crt0.S
@@ -9,10 +9,12 @@ _start:
 	movq %rsp, %rbp
 
 	# We need those in a moment when we call main.
+	pushq %rdx
 	pushq %rsi
 	pushq %rdi
 
 	# Prepare signals, memory allocation, stdio and such.
+	movq %rdx, %rdi
 	call _init_libc
 
 	# Run the global constructors.
@@ -21,6 +23,7 @@ _start:
 	# Restore argc and argv.
 	popq %rdi
 	popq %rsi
+	popq %rdx
 
 	# Run main
 	call main
diff --git a/kernel/include/kernel/Process.h b/kernel/include/kernel/Process.h
index a124e6b3ec..dbfd09910d 100644
--- a/kernel/include/kernel/Process.h
+++ b/kernel/include/kernel/Process.h
@@ -31,7 +31,8 @@ namespace Kernel
 		{
 			uintptr_t entry { 0 };
 			int argc { 0 };
-			char** argv  { 0 };
+			char** argv { nullptr };
+			char** envp { nullptr };
 		};
 
 	public:
diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index 8c0d6c63a4..3d03fce173 100644
--- a/kernel/kernel/Process.cpp
+++ b/kernel/kernel/Process.cpp
@@ -78,6 +78,7 @@ namespace Kernel
 
 		process->m_userspace_entry.argc = 1;
 		process->m_userspace_entry.argv = argv;
+		process->m_userspace_entry.envp = (char**)0x69696969;
 		process->m_userspace_entry.entry = elf->file_header_native().e_entry;
 
 		delete elf;
diff --git a/kernel/kernel/Thread.cpp b/kernel/kernel/Thread.cpp
index 68ea0dc9a1..8e2d892ec7 100644
--- a/kernel/kernel/Thread.cpp
+++ b/kernel/kernel/Thread.cpp
@@ -9,7 +9,7 @@
 namespace Kernel
 {
 
-	extern "C" void thread_userspace_trampoline(uint64_t rsp, uint64_t rip, int argc, char** argv);
+	extern "C" void thread_userspace_trampoline(uint64_t rsp, uint64_t rip, int argc, char** argv, char** envp);
 	extern "C" uintptr_t read_rip();
 
 	template<size_t size, typename T>
@@ -131,7 +131,7 @@ namespace Kernel
 			[](void*)
 			{
 				const auto& entry = Process::current().userspace_entry();
-				thread_userspace_trampoline(Thread::current().rsp(), entry.entry, entry.argc, entry.argv);
+				thread_userspace_trampoline(Thread::current().rsp(), entry.entry, entry.argc, entry.argv, entry.envp);
 				ASSERT_NOT_REACHED();
 			}
 		);
diff --git a/libc/unistd.cpp b/libc/unistd.cpp
index 0d7dd6c4f6..1aa6f9da67 100644
--- a/libc/unistd.cpp
+++ b/libc/unistd.cpp
@@ -9,10 +9,13 @@
 #include <sys/syscall.h>
 #include <unistd.h>
 
+char** environ;
+
 extern "C" void _init_stdio();
 
-extern "C" void _init_libc()
+extern "C" void _init_libc(char** _environ)
 {
+	environ = _environ;
 	_init_stdio();
 }