Add geteuid() and getegid().

There's no support for set-uid or set-gid executables yet so these don't
actually do anything. It's just nice to get the boilerplate stuff in.

Kernel/Process.cpp

@@ -303,7 +303,7 @@ int Process::exec(const String& path, Vector<String>&& arguments, Vector<String>
         return error;
     }
 
-    if (!handle->metadata().mayExecute(m_uid, m_gid))
+    if (!handle->metadata().mayExecute(m_euid, m_egid))
         return -EACCES;
 
     auto elfData = handle->readEntireFile();
@@ -563,6 +563,8 @@ Process::Process(String&& name, uid_t uid, gid_t gid, pid_t parentPID, RingLevel
     , m_pid(next_pid++) // FIXME: RACE: This variable looks racy!
     , m_uid(uid)
     , m_gid(gid)
+    , m_euid(uid)
+    , m_egid(gid)
     , m_state(Runnable)
     , m_ring(ring)
     , m_cwd(move(cwd))
@@ -1219,6 +1221,16 @@ gid_t Process::sys$getgid()
     return m_gid;
 }
 
+uid_t Process::sys$geteuid()
+{
+    return m_euid;
+}
+
+gid_t Process::sys$getegid()
+{
+    return m_egid;
+}
+
 pid_t Process::sys$getpid()
 {
     return m_pid;

Kernel/Process.h

@@ -56,8 +56,9 @@ public:
     TSS32& tss() { return m_tss; }
     State state() const { return m_state; }
     uid_t uid() const { return m_uid; }
-    uid_t gid() const { return m_gid; }
-
+    gid_t gid() const { return m_gid; }
+    uid_t euid() const { return m_euid; }
+    gid_t egid() const { return m_egid; }
     pid_t parentPID() const { return m_parentPID; }
 
     const FarPtr& farPtr() const { return m_farPtr; }
@@ -91,6 +92,8 @@ public:
     int sys$tcsetpgrp(int fd, pid_t pgid);
     uid_t sys$getuid();
     gid_t sys$getgid();
+    uid_t sys$geteuid();
+    gid_t sys$getegid();
     pid_t sys$getpid();
     int sys$open(const char* path, int options);
     int sys$close(int fd);
@@ -175,6 +178,8 @@ private:
     pid_t m_pid { 0 };
     uid_t m_uid { 0 };
     gid_t m_gid { 0 };
+    uid_t m_euid { 0 };
+    gid_t m_egid { 0 };
     pid_t m_sid { 0 };
     pid_t m_pgid { 0 };
     DWORD m_ticks { 0 };

Kernel/Syscall.cpp

@@ -132,6 +132,10 @@ static DWORD handle(RegisterDump& regs, DWORD function, DWORD arg1, DWORD arg2,
         return current->sys$fork(regs);
     case Syscall::PosixExecve:
         return current->sys$execve((const char*)arg1, (const char**)arg2, (const char**)arg3);
+    case Syscall::PosixGeteuid:
+        return current->sys$geteuid();
+    case Syscall::PosixGetegid:
+        return current->sys$getegid();
     default:
         kprintf("<%u> int0x80: Unknown function %x requested {%x, %x, %x}\n", current->pid(), function, arg1, arg2, arg3);
         break;

Kernel/Syscall.h

@@ -49,6 +49,8 @@ enum Function {
     PosixTcgetpgrp = 0x2017,
     PosixFork = 0x2018,
     PosixExecve = 0x2019,
+    PosixGeteuid = 0x2020,
+    PosixGetegid = 0x2021,
 };
 
 void initialize();

LibC/unistd.cpp

@@ -27,6 +27,16 @@ gid_t getgid()
     return Syscall::invoke(Syscall::PosixGetgid);
 }
 
+uid_t geteuid()
+{
+    return Syscall::invoke(Syscall::PosixGeteuid);
+}
+
+gid_t getegid()
+{
+    return Syscall::invoke(Syscall::PosixGetegid);
+}
+
 pid_t getpid()
 {
     return Syscall::invoke(Syscall::PosixGetpid);

LibC/unistd.h

@@ -15,6 +15,8 @@ pid_t setsid();
 int setpgid(pid_t pid, pid_t pgid);
 pid_t getpgid(pid_t);
 pid_t getpgrp();
+uid_t geteuid();
+gid_t getegid();
 uid_t getuid();
 gid_t getgid();
 pid_t getpid();