From b254ade69b91db621752dcbcff692f0d7b2bf921 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Sun, 11 Jun 2023 22:27:53 +0300
Subject: [PATCH] Kernel: Add SYS_GET_{,E}{UID,GID}

---
 kernel/include/kernel/Process.h |  5 +++++
 kernel/kernel/Syscall.cpp       | 32 ++++++++++++++++++++++++++
 libc/include/sys/syscall.h      |  4 ++++
 libc/unistd.cpp                 | 40 +++++++++++++++++++++++++++++++++
 4 files changed, 81 insertions(+)

diff --git a/kernel/include/kernel/Process.h b/kernel/include/kernel/Process.h
index 7f2ac097d..42c6ea735 100644
--- a/kernel/include/kernel/Process.h
+++ b/kernel/include/kernel/Process.h
@@ -65,6 +65,11 @@ namespace Kernel
 		BAN::ErrorOr<void> set_reuid(uid_t, uid_t);
 		BAN::ErrorOr<void> set_regid(gid_t, gid_t);
 
+		uid_t get_uid() const { return m_credentials.ruid(); }
+		gid_t get_gid() const { return m_credentials.rgid(); }
+		uid_t get_euid() const { return m_credentials.euid(); }
+		gid_t get_egid() const { return m_credentials.egid(); }
+
 		BAN::ErrorOr<int> open(BAN::StringView, int);
 		BAN::ErrorOr<int> openat(int, BAN::StringView, int);
 		BAN::ErrorOr<void> close(int fd);
diff --git a/kernel/kernel/Syscall.cpp b/kernel/kernel/Syscall.cpp
index aa30f4a63..ed63ef84c 100644
--- a/kernel/kernel/Syscall.cpp
+++ b/kernel/kernel/Syscall.cpp
@@ -208,6 +208,26 @@ namespace Kernel
 		return 0;
 	}
 
+	long sys_get_uid()
+	{
+		return Process::current().get_uid();
+	}
+
+	long sys_get_gid()
+	{
+		return Process::current().get_gid();
+	}
+
+	long sys_get_euid()
+	{
+		return Process::current().get_euid();
+	}
+
+	long sys_get_egid()
+	{
+		return Process::current().get_egid();
+	}
+
 	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)
@@ -303,6 +323,18 @@ namespace Kernel
 		case SYS_SET_REGID:
 			ret = sys_set_regid((gid_t)arg1, (gid_t)arg2);
 			break;
+		case SYS_GET_UID:
+			ret = sys_get_uid();
+			break;
+		case SYS_GET_GID:
+			ret = sys_get_gid();
+			break;
+		case SYS_GET_EUID:
+			ret = sys_get_euid();
+			break;
+		case SYS_GET_EGID:
+			ret = sys_get_egid();
+			break;
 		default:
 			dwarnln("Unknown syscall {}", syscall);
 			ret = -ENOSYS;
diff --git a/libc/include/sys/syscall.h b/libc/include/sys/syscall.h
index 311616d25..272b31277 100644
--- a/libc/include/sys/syscall.h
+++ b/libc/include/sys/syscall.h
@@ -32,6 +32,10 @@ __BEGIN_DECLS
 #define SYS_SET_EGID 25
 #define SYS_SET_REUID 26
 #define SYS_SET_REGID 27
+#define SYS_GET_UID 28
+#define SYS_GET_GID 29
+#define SYS_GET_EUID 30
+#define SYS_GET_EGID 31
 
 __END_DECLS
 
diff --git a/libc/unistd.cpp b/libc/unistd.cpp
index b5474a2db..54b7f73f3 100644
--- a/libc/unistd.cpp
+++ b/libc/unistd.cpp
@@ -213,6 +213,26 @@ long syscall(long syscall, ...)
 			ret = Kernel::syscall(SYS_SET_REGID, rgid, egid);
 			break;
 		}
+		case SYS_GET_UID:
+		{
+			ret = Kernel::syscall(SYS_GET_UID);
+			break;
+		}
+		case SYS_GET_GID:
+		{
+			ret = Kernel::syscall(SYS_GET_GID);
+			break;
+		}
+		case SYS_GET_EUID:
+		{
+			ret = Kernel::syscall(SYS_GET_EUID);
+			break;
+		}
+		case SYS_GET_EGID:
+		{
+			ret = Kernel::syscall(SYS_GET_EGID);
+			break;
+		}
 		default:
 			puts("LibC: Unhandeled syscall");
 			ret = -ENOSYS;
@@ -322,6 +342,26 @@ unsigned int sleep(unsigned int seconds)
 	return syscall(SYS_SLEEP, seconds);
 }
 
+uid_t getuid(void)
+{
+	return syscall(SYS_GET_UID);
+}
+
+gid_t getgid(void)
+{
+	return syscall(SYS_GET_GID);
+}
+
+uid_t geteuid(void)
+{
+	return syscall(SYS_GET_EUID);
+}
+
+gid_t getegid(void)
+{
+	return syscall(SYS_GET_EGID);
+}
+
 int seteuid(uid_t uid)
 {
 	return syscall(SYS_SET_EUID, uid);