6 files changed, 115 insertions, 2 deletions
diff --git a/src/sys/include/compat/unix/syscall.h b/src/sys/include/compat/unix/syscall.h
index 38419af..9b76139 100644
--- a/src/sys/include/compat/unix/syscall.h
+++ b/src/sys/include/compat/unix/syscall.h
@@ -35,6 +35,7 @@
 #include <sys/param.h>
 #include <sys/mount.h>
 #include <sys/syscall.h>
+#include <os/ucred.h>
 #include <os/iotap.h>
 #include <os/reboot.h>
 #include <dms/dms.h>
@@ -98,7 +99,8 @@ scret_t(*g_unix_sctab[])(struct syscall_args *) = {
     [SYS_close] = sys_close,
     [SYS_lseek] = sys_lseek,
     [SYS_socket] = sys_socket,
-    [SYS_listen] = sys_listen
+    [SYS_listen] = sys_listen,
+    [SYS_seteuid] = sys_seteuid
 };
 
 #endif  /* !_NEED_UNIX_SCTAB */
diff --git a/src/sys/include/os/ucred.h b/src/sys/include/os/ucred.h
new file mode 100644
index 0000000..6e3e4b4
--- /dev/null
+++ b/src/sys/include/os/ucred.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _OS_UCRED_H_
+#define _OS_UCRED_H_ 1
+
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/ucred.h>
+#include <sys/proc.h>
+
+/*
+ * Initialize user credientials
+ *
+ * @proc: Current process
+ * @cred: credientials to initialize
+ *
+ * XXX: 'proc' being NULL drops the creds to root
+ *
+ * Returns zero on success, otherwise a less
+ * than zero value on failure.
+ */
+int ucred_init(struct proc *proc, struct ucred *cred);
+
+/*
+ * Set effective user ID
+ */
+int seteuid(uid_t euid);
+
+/*
+ * Set EUID system call
+ */
+scret_t sys_seteuid(struct syscall_args *scargs);
+
+#endif  /* !_OS_UCRED_H_ */
diff --git a/src/sys/include/sys/proc.h b/src/sys/include/sys/proc.h
index a547233..b188d50 100644
--- a/src/sys/include/sys/proc.h
+++ b/src/sys/include/sys/proc.h
@@ -30,6 +30,7 @@
 #ifndef _SYS_PROC_H_
 #define _SYS_PROC_H_
 
+#include <sys/ucred.h>
 #include <sys/types.h>
 #include <sys/syscall.h>
 #include <sys/cdefs.h>
@@ -91,6 +92,7 @@ struct proc {
     struct penv_blk *envblk;
     struct ptrbox *envblk_box;
     struct proc *parent;
+    struct ucred cred;
     mac_level_t level;
     struct spinlock maplist_lock;
     sigtab_t sigtab;
diff --git a/src/sys/include/sys/syscall.h b/src/sys/include/sys/syscall.h
index 2ca712f..d148405 100644
--- a/src/sys/include/sys/syscall.h
+++ b/src/sys/include/sys/syscall.h
@@ -61,6 +61,7 @@
 #define SYS_lseek       0x10    /* seek to end of file */
 #define SYS_socket      0x11    /* get a socket fd */
 #define SYS_listen      0x12    /* listen on a socket */
+#define SYS_seteuid     0x13    /* set effective UID */
 
 typedef __ssize_t scret_t;
 typedef __ssize_t scarg_t;
diff --git a/src/sys/include/sys/types.h b/src/sys/include/sys/types.h
index b1d5994..745eed7 100644
--- a/src/sys/include/sys/types.h
+++ b/src/sys/include/sys/types.h
@@ -96,7 +96,6 @@ typedef __size_t uintptr_t;
 typedef __size_t off_t;
 typedef int pid_t;
 typedef int dev_t;
-typedef __uint32_t uid_t;
 typedef __uint32_t mode_t;
 typedef __uint32_t ino_t;
 typedef __uint32_t nlink_t;
diff --git a/src/sys/include/sys/ucred.h b/src/sys/include/sys/ucred.h
new file mode 100644
index 0000000..ab44b6c
--- /dev/null
+++ b/src/sys/include/sys/ucred.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _SYS_UCRED_H_
+#define _SYS_UCRED_H_ 1
+
+#include <sys/types.h>
+
+/*
+ * Represents current user credientials
+ *
+ * @euid: Effective user ID
+ * @ruid: Real user ID
+ * @suid: Saved UID
+ */
+struct ucred {
+    uid_t euid;
+    uid_t ruid;
+    uid_t suid;
+};
+
+#endif  /* !_SYS_UCRED_H_ */