LibC: implement setenv, unsetenv, putenv

kernel/include/kernel/Process.h

@@ -57,6 +57,8 @@ namespace Kernel
 		int block_until_exit();
 		BAN::ErrorOr<pid_t> wait(pid_t pid, int* stat_loc, int options);
 
+		BAN::ErrorOr<void> setenvp(char** envp);
+
 		BAN::ErrorOr<int> open(BAN::StringView, int);
 		BAN::ErrorOr<void> close(int fd);
 		BAN::ErrorOr<size_t> read(int fd, void* buffer, size_t count);

kernel/kernel/Process.cpp

@@ -389,6 +389,13 @@ namespace Kernel
 		return ret;
 	}
 
+	BAN::ErrorOr<void> Process::setenvp(char** envp)
+	{
+		LockGuard _(m_lock);
+		m_userspace_info.envp = envp;
+		return {};
+	}
+
 	void Process::load_elf(LibELF::ELF& elf)
 	{
 		ASSERT(elf.is_native());

kernel/kernel/Syscall.cpp

@@ -136,6 +136,14 @@ namespace Kernel
 		return 0;
 	}
 
+	long sys_setenvp(char** envp)
+	{
+		auto ret = Process::current().setenvp(envp);
+		if (ret.is_error())
+			return -ret.error().get_error_code();
+		return 0;
+	}
+
 	extern "C" long sys_fork_trampoline();
 
 	extern "C" long cpp_syscall_handler(int syscall, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, uintptr_t arg4, uintptr_t arg5)
@@ -204,6 +212,9 @@ namespace Kernel
 		case SYS_STAT:
 			ret = sys_stat((const char*)arg1, (struct stat*)arg2, (int)arg3);
 			break;
+		case SYS_SETENVP:
+			ret = sys_setenvp((char**)arg1);
+			break;
 		default:
 			Kernel::panic("Unknown syscall {}", syscall);
 		}