From d9f933df7b1b1daef238bb7b0728c9f04097a977 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Mon, 27 Jul 2020 16:32:30 +0200
Subject: [PATCH] UserspaceEmulator: Implement the setuid() and setgid()
 syscalls

Note that running a setuid program (e.g /bin/ping) in UE does not
actually run uid=0. You'll have to run UE itself as uid=0 if you want
to test programs that do setuid/setgid.
---
 DevTools/UserspaceEmulator/Emulator.cpp | 14 ++++++++++++++
 DevTools/UserspaceEmulator/Emulator.h   |  2 ++
 2 files changed, 16 insertions(+)

diff --git a/DevTools/UserspaceEmulator/Emulator.cpp b/DevTools/UserspaceEmulator/Emulator.cpp
index a8bc5e61c9..42cc29c3e5 100644
--- a/DevTools/UserspaceEmulator/Emulator.cpp
+++ b/DevTools/UserspaceEmulator/Emulator.cpp
@@ -278,6 +278,10 @@ u32 Emulator::virt_syscall(u32 function, u32 arg1, u32 arg2, u32 arg3)
         return virt$getuid();
     case SC_getgid:
         return virt$getgid();
+    case SC_setuid:
+        return virt$setuid(arg1);
+    case SC_setgid:
+        return virt$setgid(arg2);
     case SC_close:
         return virt$close(arg1);
     case SC_fstat:
@@ -791,6 +795,16 @@ gid_t Emulator::virt$getgid()
     return getgid();
 }
 
+int Emulator::virt$setuid(uid_t uid)
+{
+    return syscall(SC_setuid, uid);
+}
+
+int Emulator::virt$setgid(gid_t gid)
+{
+    return syscall(SC_setgid, gid);
+}
+
 u32 Emulator::virt$write(int fd, FlatPtr data, ssize_t size)
 {
     if (size < 0)
diff --git a/DevTools/UserspaceEmulator/Emulator.h b/DevTools/UserspaceEmulator/Emulator.h
index f08fd53efa..2093e3d30f 100644
--- a/DevTools/UserspaceEmulator/Emulator.h
+++ b/DevTools/UserspaceEmulator/Emulator.h
@@ -88,6 +88,8 @@ private:
     u32 virt$pledge(u32);
     uid_t virt$getuid();
     gid_t virt$getgid();
+    int virt$setuid(uid_t);
+    int virt$setgid(gid_t);
     u32 virt$read(int, FlatPtr, ssize_t);
     u32 virt$write(int, FlatPtr, ssize_t);
     u32 virt$mprotect(FlatPtr, size_t, int);