diff --git a/src/drivers/generic/extfs/probe.c b/src/drivers/generic/extfs/probe.c
index 931add18..898fe9f5 100644
--- a/src/drivers/generic/extfs/probe.c
+++ b/src/drivers/generic/extfs/probe.c
@@ -166,8 +166,8 @@ vnode* ext_make_vnode(ext_cache* cache, uint32_t ino, mount* mnt)
     vn->desc = (dev_desc)handle;
     vn->vtype = vtype;
     vn->blkSize = 1;
-    vn->owner_uid = inode->uid;
-    vn->group_uid = inode->gid;
+    vn->uid = inode->uid;
+    vn->gid = inode->gid;
     vn->filesize = (uint64_t)inode->size | (ext_sb_supports_64bit_filesize ? (uint64_t)inode->dir_acl << 32 : 0);
     vn->times.access = inode->access_time;
     vn->times.birth = inode->creation_time;
diff --git a/src/drivers/generic/initrd/main.c b/src/drivers/generic/initrd/main.c
index 9bacf96b..a94981d0 100644
--- a/src/drivers/generic/initrd/main.c
+++ b/src/drivers/generic/initrd/main.c
@@ -260,8 +260,8 @@ initrd_inode* create_inode_boot(const ustar_hdr* hdr)
     ino->vnode->desc = (uintptr_t)ino;
     ino->vnode->filesize = ino->filesize;
     ino->vnode->blkSize = 1;
-    ino->vnode->owner_uid = 0;
-    ino->vnode->group_uid = 0;
+    ino->vnode->uid = 0;
+    ino->vnode->gid = 0;
     ino->vnode->inode = ino->ino;
     ino->vnode->perm = ino->perm;
     ino->vnode->times.change = oct2bin(hdr->last_mod, strnlen(hdr->last_mod, 12));
diff --git a/src/oboskrnl/arch/x86_64/gdbstub/vFile.c b/src/oboskrnl/arch/x86_64/gdbstub/vFile.c
index 44b0907f..e5b4adf2 100644
--- a/src/oboskrnl/arch/x86_64/gdbstub/vFile.c
+++ b/src/oboskrnl/arch/x86_64/gdbstub/vFile.c
@@ -197,8 +197,8 @@ static obos_status common_stat(vnode* vn, struct gdb_stat* out)
     out->st_dev = 0;
     out->st_ino = vn->inode;
     out->st_nlink = vn->refs;
-    out->st_uid = vn->owner_uid;
-    out->st_gid = vn->group_uid;
+    out->st_uid = vn->uid;
+    out->st_gid = vn->gid;
     out->st_rdev = 0;
     out->st_size = vn->filesize;
     out->st_blksize = vn->blkSize;
diff --git a/src/oboskrnl/driver_interface/drv_sys.c b/src/oboskrnl/driver_interface/drv_sys.c
index 06c41145..7fa55e7c 100644
--- a/src/oboskrnl/driver_interface/drv_sys.c
+++ b/src/oboskrnl/driver_interface/drv_sys.c
@@ -24,7 +24,7 @@
 
 handle Sys_LoadDriver(const void* file, size_t szFile, obos_status* ustatus)
 {
-    if (Core_GetCurrentThread()->proc->currentUID != ROOT_UID)
+    if (Core_GetCurrentThread()->proc->euid != ROOT_UID)
     {
         if (ustatus) *ustatus = OBOS_STATUS_ACCESS_DENIED;
         return HANDLE_INVALID;
@@ -62,7 +62,7 @@ handle Sys_LoadDriver(const void* file, size_t szFile, obos_status* ustatus)
 }
 
 #define perm_check_impl(ret) do {\
-    if (Core_GetCurrentThread()->proc->currentUID != ROOT_UID)\
+    if (Core_GetCurrentThread()->proc->euid != ROOT_UID)\
         return (ret);\
 } while(0)
 #define perm_check() perm_check_impl(OBOS_STATUS_ACCESS_DENIED)
diff --git a/src/oboskrnl/execve.c b/src/oboskrnl/execve.c
index d9aac177..620ad9bd 100644
--- a/src/oboskrnl/execve.c
+++ b/src/oboskrnl/execve.c
@@ -144,8 +144,8 @@ obos_status Sys_ExecVE(const char* upath, char* const* argv, char* const* envp)
     void* kbuf = Mm_VirtualMemoryAlloc(&Mm_KernelContext, nullptr, szBuf, OBOS_PROTECTION_READ_ONLY, 0, &file, nullptr);
     bool set_uid = file.vn->perm.set_uid;
     bool set_gid = file.vn->perm.set_gid;
-    uid target_uid = set_uid ? file.vn->owner_uid : Core_GetCurrentThread()->proc->currentUID;
-    gid target_gid = set_gid ? file.vn->group_uid : Core_GetCurrentThread()->proc->currentGID;
+    uid target_euid = set_uid ? file.vn->uid : Core_GetCurrentThread()->proc->euid;
+    gid target_egid = set_gid ? file.vn->gid : Core_GetCurrentThread()->proc->egid;
     Vfs_FdClose(&file);
 
     char** kargv = allocate_user_vector_as_kernel(ctx, argv, &argc, &status);
@@ -309,8 +309,10 @@ obos_status Sys_ExecVE(const char* upath, char* const* argv, char* const* envp)
 
     aux.at_secure = set_gid || set_uid;
 
-    Core_GetCurrentThread()->proc->currentUID = target_uid;
-    Core_GetCurrentThread()->proc->currentGID = target_gid;
+    Core_GetCurrentThread()->proc->euid = target_euid;
+    Core_GetCurrentThread()->proc->egid = target_egid;
+    Core_GetCurrentThread()->proc->sgid = -1;
+    Core_GetCurrentThread()->proc->sgid = -1;
 
     OBOSS_HandControlTo(ctx, &aux);
 }
diff --git a/src/oboskrnl/scheduler/process.h b/src/oboskrnl/scheduler/process.h
index 324a1b9c..ac697526 100644
--- a/src/oboskrnl/scheduler/process.h
+++ b/src/oboskrnl/scheduler/process.h
@@ -37,8 +37,8 @@ typedef struct process
 
 	struct process_group* pgrp;
 
-	uid currentUID;
-	gid currentGID;
+	uid euid, ruid, suid;
+	gid egid, rgid, sgid;
 	
 	uint32_t exitCode;
 	bool dead;
diff --git a/src/oboskrnl/scheduler/sched_sys.c b/src/oboskrnl/scheduler/sched_sys.c
index a527ec93..15421adb 100644
--- a/src/oboskrnl/scheduler/sched_sys.c
+++ b/src/oboskrnl/scheduler/sched_sys.c
@@ -663,29 +663,121 @@ obos_status Sys_WaitProcess(handle proc, int* wstatus, int options, uint32_t* pi
     return status;
 }
 
+uid Sys_GetUid()
+{ return Core_GetCurrentThread()->proc->ruid; }
+gid Sys_GetGid()
+{ return Core_GetCurrentThread()->proc->rgid; }
 
-obos_status Sys_SetUid(uid to)
+static bool check_unpriv_uid(uid uid)
 {
-    process* proc = Core_GetCurrentThread()->proc;
-    if (proc->currentUID != 0)
-        return OBOS_STATUS_ACCESS_DENIED;
-    proc->currentUID = to;
+    return (uid != Core_GetCurrentThread()->proc->ruid) && 
+           (uid != Core_GetCurrentThread()->proc->euid) && 
+           (uid != Core_GetCurrentThread()->proc->suid);
+}
+static bool check_unpriv_gid(gid gid)
+{
+    return (gid != Core_GetCurrentThread()->proc->rgid) && 
+           (gid != Core_GetCurrentThread()->proc->egid) && 
+           (gid != Core_GetCurrentThread()->proc->sgid);
+}
+
+obos_status Sys_SetRESUid(uid ruid, uid euid, uid suid)
+{
+    if (Core_GetCurrentThread()->proc->euid != 0)
+    {
+        if ((ruid != -1) && !check_unpriv_uid(ruid))
+            return OBOS_STATUS_ACCESS_DENIED;
+        if ((euid != -1) && !check_unpriv_uid(euid))
+            return OBOS_STATUS_ACCESS_DENIED;
+        if ((suid != -1) && !check_unpriv_uid(suid))
+            return OBOS_STATUS_ACCESS_DENIED;
+        if (ruid != -1)
+            Core_GetCurrentThread()->proc->ruid = ruid;
+        if (euid != -1)
+            Core_GetCurrentThread()->proc->euid = euid;
+        if (suid != -1)
+            Core_GetCurrentThread()->proc->suid = suid;
+    }
+    else
+    {
+        if (ruid != -1) Core_GetCurrentThread()->proc->ruid = ruid;
+        if (euid != -1) Core_GetCurrentThread()->proc->euid = euid;
+        if (suid != -1) Core_GetCurrentThread()->proc->suid = suid;
+    }
     return OBOS_STATUS_SUCCESS;
 }
 
-obos_status Sys_SetGid(gid to)
+obos_status Sys_SetRESGid(gid rgid, gid egid, gid sgid)
 {
-    process* proc = Core_GetCurrentThread()->proc;
-    if (proc->currentUID != 0)
-        return OBOS_STATUS_ACCESS_DENIED;
-    proc->currentGID = to;
+    if (Core_GetCurrentThread()->proc->euid != 0)
+    {
+        if ((rgid != -1) && !check_unpriv_gid(rgid))
+            return OBOS_STATUS_ACCESS_DENIED;
+        if ((egid != -1) && !check_unpriv_gid(egid))
+            return OBOS_STATUS_ACCESS_DENIED;
+        if ((sgid != -1) && !check_unpriv_gid(sgid))
+            return OBOS_STATUS_ACCESS_DENIED;
+        if (rgid != -1)
+            Core_GetCurrentThread()->proc->rgid = rgid;
+        if (egid != -1)
+            Core_GetCurrentThread()->proc->egid = egid;
+        if (sgid != -1)
+            Core_GetCurrentThread()->proc->sgid = sgid;
+    }
+    else
+    {
+        if (rgid != -1) Core_GetCurrentThread()->proc->rgid = rgid;
+        if (egid != -1) Core_GetCurrentThread()->proc->egid = egid;
+        if (sgid != -1) Core_GetCurrentThread()->proc->sgid = sgid;
+    }
     return OBOS_STATUS_SUCCESS;
 }
 
-uid Sys_GetUid()
-{ return Core_GetCurrentThread()->proc->currentUID; }
-gid Sys_GetGid()
-{ return Core_GetCurrentThread()->proc->currentGID; }
+obos_status Sys_GetRESUid(uid* ruid, uid* euid, uid* suid)
+{
+    if (ruid)
+        memcpy_k_to_usr(ruid, &Core_GetCurrentThread()->proc->ruid, sizeof(uid));
+    if (euid)
+        memcpy_k_to_usr(euid, &Core_GetCurrentThread()->proc->euid, sizeof(uid));
+    if (suid)
+        memcpy_k_to_usr(suid, &Core_GetCurrentThread()->proc->suid, sizeof(uid));
+    return OBOS_STATUS_SUCCESS;
+}
+
+obos_status Sys_GetRESGid(gid* rgid, gid* egid, gid* sgid)
+{
+    if (rgid)
+        memcpy_k_to_usr(rgid, &Core_GetCurrentThread()->proc->rgid, sizeof(gid));
+    if (egid)
+        memcpy_k_to_usr(egid, &Core_GetCurrentThread()->proc->egid, sizeof(gid));
+    if (sgid)
+        memcpy_k_to_usr(sgid, &Core_GetCurrentThread()->proc->sgid, sizeof(gid));
+    return OBOS_STATUS_SUCCESS;
+}
+
+obos_status Sys_SetUid(uid uid)
+{
+    if (Core_GetCurrentThread()->proc->euid == 0)
+    {
+        Core_GetCurrentThread()->proc->ruid = uid;
+        Core_GetCurrentThread()->proc->euid = uid;
+        Core_GetCurrentThread()->proc->suid = uid;
+        return OBOS_STATUS_SUCCESS;
+    }
+    return OBOS_STATUS_ACCESS_DENIED;
+}
+
+obos_status Sys_SetGid(gid gid)
+{
+    if (Core_GetCurrentThread()->proc->euid == 0)
+    {
+        Core_GetCurrentThread()->proc->rgid = gid;
+        Core_GetCurrentThread()->proc->egid = gid;
+        Core_GetCurrentThread()->proc->sgid = gid;
+        return OBOS_STATUS_SUCCESS;
+    }
+    return OBOS_STATUS_ACCESS_DENIED;
+}
 
 obos_status Sys_SetProcessGroup(handle process, uint32_t pgid)
 {
diff --git a/src/oboskrnl/scheduler/sched_sys.h b/src/oboskrnl/scheduler/sched_sys.h
index d0381dc5..673658b2 100644
--- a/src/oboskrnl/scheduler/sched_sys.h
+++ b/src/oboskrnl/scheduler/sched_sys.h
@@ -66,10 +66,14 @@ handle Sys_ProcessGetChildHandle();
 // If HANDLE_ANY to make it choose an arbitrary child process.
 obos_status Sys_WaitProcess(handle proc, int* status, int options, uint32_t* ret_pid);
 
-obos_status Sys_SetUid(uid to);
-obos_status Sys_SetGid(gid to);
 uid Sys_GetUid();
 gid Sys_GetGid();
+obos_status Sys_SetRESUid(uid ruid, uid euid, uid suid);
+obos_status Sys_SetRESGid(gid rgid, gid egid, gid sgid);
+obos_status Sys_GetRESUid(uid* ruid, uid* euid, uid* suid);
+obos_status Sys_GetRESGid(gid* rgid, gid* egid, gid* sgid);
+obos_status Sys_SetUid(uid uid);
+obos_status Sys_SetGid(gid gid);
 
 obos_status Sys_SetProcessGroup(handle proc, uint32_t pgid);
 obos_status Sys_GetProcessGroup(handle proc, uint32_t* pgid);
\ No newline at end of file
diff --git a/src/oboskrnl/syscall.c b/src/oboskrnl/syscall.c
index a990fc6d..2902ed99 100644
--- a/src/oboskrnl/syscall.c
+++ b/src/oboskrnl/syscall.c
@@ -458,6 +458,10 @@ uintptr_t OBOS_SyscallTable[SYSCALL_END-SYSCALL_BEGIN] = {
     (uintptr_t)Sys_RenameAt,
     (uintptr_t)Sys_UTimeNSAt,
     (uintptr_t)Sys_ThreadGetStack,
+    (uintptr_t)Sys_SetRESUid,
+    (uintptr_t)Sys_SetRESGid,
+    (uintptr_t)Sys_GetRESUid,
+    (uintptr_t)Sys_GetRESGid,
 };
 
 // Arch syscall table is defined per-arch
diff --git a/src/oboskrnl/vfs/create.c b/src/oboskrnl/vfs/create.c
index 6ca818a2..772cab74 100644
--- a/src/oboskrnl/vfs/create.c
+++ b/src/oboskrnl/vfs/create.c
@@ -25,20 +25,20 @@
 
 static bool has_write_perm(vnode* parent)
 {
-    uid current_uid = Core_GetCurrentThread()->proc->currentUID;
-    uid current_gid = Core_GetCurrentThread()->proc->currentGID;
+    uid current_uid = Core_GetCurrentThread()->proc->euid;
+    uid current_gid = Core_GetCurrentThread()->proc->egid;
     if (parent->flags & VFLAGS_MOUNTPOINT)
     {
         drv_fs_info info = {};
         parent->un.mounted->fs_driver->driver->header.ftable.stat_fs_info(parent->un.mounted->device, &info);
-        if (parent->owner_uid == current_uid || parent->group_uid == current_gid)
+        if (parent->uid == current_uid || parent->gid == current_gid)
             return ~info.flags & FS_FLAGS_RDONLY;
         else
             return false; 
     }
-    if (parent->owner_uid == current_uid)
+    if (parent->uid == current_uid)
         return parent->perm.owner_write;
-    else if (parent->group_uid == current_gid)
+    else if (parent->gid == current_gid)
         return parent->perm.group_write;
     else
         return parent->perm.other_write;
@@ -94,8 +94,8 @@ obos_status Vfs_CreateNode(dirent* parent, const char* name, uint32_t vtype, fil
             return OBOS_STATUS_INVALID_ARGUMENT;
     }
     vnode* vn = Vfs_Calloc(1, sizeof(vnode));
-    vn->group_uid = Core_GetCurrentThread()->proc->currentGID;
-    vn->owner_uid = Core_GetCurrentThread()->proc->currentUID;
+    vn->gid = Core_GetCurrentThread()->proc->egid;
+    vn->uid = Core_GetCurrentThread()->proc->euid;
     vn->perm = mode;
     vn->flags = 0;
     vn->vtype = vtype;
diff --git a/src/oboskrnl/vfs/dirent.c b/src/oboskrnl/vfs/dirent.c
index 4c110ce8..3d28c8c7 100644
--- a/src/oboskrnl/vfs/dirent.c
+++ b/src/oboskrnl/vfs/dirent.c
@@ -461,8 +461,8 @@ vnode* Drv_AllocateVNode(driver_id* drv, dev_desc desc, size_t filesize, vdev**
     vn->inode = devfs_inode++;
     vn->perm = default_fileperm;
     vn->vtype = type;
-    vn->group_uid = ROOT_GID;
-    vn->owner_uid = ROOT_UID;
+    vn->gid = ROOT_GID;
+    vn->uid = ROOT_UID;
     vn->times.access = get_current_time();
     vn->times.birth = vn->times.access;
     vn->times.change = vn->times.access;
@@ -650,12 +650,12 @@ char* VfsH_DirentPath(dirent* ent, dirent* relative_to)
 
 static bool check_chdir_perms(dirent* ent)
 {
-    uid uid = Core_GetCurrentThread()->proc->currentUID;
-    gid gid = Core_GetCurrentThread()->proc->currentGID;
+    uid uid = Core_GetCurrentThread()->proc->euid;
+    gid gid = Core_GetCurrentThread()->proc->egid;
 
-    if (uid == ent->vnode->owner_uid)
+    if (uid == ent->vnode->uid)
         return ent->vnode->perm.owner_exec;
-    else if (gid == ent->vnode->group_uid)
+    else if (gid == ent->vnode->gid)
         return ent->vnode->perm.group_exec;
     else
         return ent->vnode->perm.other_exec;
diff --git a/src/oboskrnl/vfs/dummy_devices.c b/src/oboskrnl/vfs/dummy_devices.c
index 0275881d..a4e043d5 100644
--- a/src/oboskrnl/vfs/dummy_devices.c
+++ b/src/oboskrnl/vfs/dummy_devices.c
@@ -417,8 +417,8 @@ static void init_desc(dev_desc desc)
     dirent* ent = Vfs_Calloc(1, sizeof(dirent));
     vnode* vn = Vfs_Calloc(1, sizeof(vnode));
 
-    vn->owner_uid = 0;
-    vn->group_uid = 0;
+    vn->uid = 0;
+    vn->gid = 0;
     vn->desc = desc;
     get_max_blk_count(desc, &vn->filesize);
 
diff --git a/src/oboskrnl/vfs/fd.c b/src/oboskrnl/vfs/fd.c
index 33f98597..74789443 100644
--- a/src/oboskrnl/vfs/fd.c
+++ b/src/oboskrnl/vfs/fd.c
@@ -94,7 +94,7 @@ OBOS_EXPORT obos_status Vfs_FdOpenVnode(fd* const desc, void* vn, uint32_t oflag
     desc->flags |= FD_FLAGS_OPEN;
     desc->flags |= FD_FLAGS_READ;
     desc->flags |= FD_FLAGS_WRITE;
-    if (desc->vn->owner_uid == Core_GetCurrentThread()->proc->currentUID || Core_GetCurrentThread()->proc->currentUID == 0)
+    if (desc->vn->uid == Core_GetCurrentThread()->proc->euid || Core_GetCurrentThread()->proc->euid == 0)
     {
         // We have owner perms.
         struct vnode* const vn = desc->vn;
@@ -105,7 +105,7 @@ OBOS_EXPORT obos_status Vfs_FdOpenVnode(fd* const desc, void* vn, uint32_t oflag
         if (oflags & FD_OFLAGS_EXECUTE && !vn->perm.owner_exec)
             return OBOS_STATUS_ACCESS_DENIED;
     }
-    else if (desc->vn->group_uid == Core_GetCurrentThread()->proc->currentGID)
+    else if (desc->vn->gid == Core_GetCurrentThread()->proc->egid)
     {
         // We have group perms.
         struct vnode* const vn = desc->vn;
diff --git a/src/oboskrnl/vfs/fd_sys.c b/src/oboskrnl/vfs/fd_sys.c
index 4e13d3b7..f3a3f1eb 100644
--- a/src/oboskrnl/vfs/fd_sys.c
+++ b/src/oboskrnl/vfs/fd_sys.c
@@ -680,8 +680,8 @@ obos_status Sys_Stat(int fsfdt, handle desc, const char* upath, int flags, struc
     st.st_atim.tv_nsec = 0;
     st.st_ctim.tv_nsec = 0;
     st.st_mtim.tv_nsec = 0;
-    st.st_gid = to_stat->group_uid;
-    st.st_uid = to_stat->owner_uid;
+    st.st_gid = to_stat->gid;
+    st.st_uid = to_stat->uid;
     st.st_ino = to_stat->inode;   
     if (to_stat->flags & VFLAGS_EVENT_DEV && ~to_stat->flags & VFLAGS_DRIVER_DEAD)
         goto done;
@@ -1326,8 +1326,8 @@ obos_status Sys_CreateNamedPipe(handle dirfd, const char* upath, int mode, size_
             fifo_name = path;
     }
 
-    gid current_gid = Core_GetCurrentThread()->proc->currentGID;
-    uid current_uid = Core_GetCurrentThread()->proc->currentUID;
+    gid current_gid = Core_GetCurrentThread()->proc->egid;
+    uid current_uid = Core_GetCurrentThread()->proc->euid;
     status = Vfs_CreateNamedPipe(perm, current_gid, current_uid, parent, fifo_name, pipesize);
     Free(OBOS_KernelAllocator, path, sz_path);
     
@@ -2910,7 +2910,7 @@ obos_status Sys_FChmodAt(handle dirfd, const char* upathname, int mode, int flag
 
     have_target:
 
-    if (target->owner_uid != Sys_GetUid() && Sys_GetUid() != ROOT_UID)
+    if (target->uid != Sys_GetUid() && Sys_GetUid() != ROOT_UID)
     {
         status = OBOS_STATUS_ACCESS_DENIED;
         goto fail;
@@ -3030,7 +3030,7 @@ obos_status Sys_FChownAt(handle dirfd, const char *upathname, uid owner, gid gro
     have_target:
     OBOS_ENSURE(target);
 
-    if (target->owner_uid != Sys_GetUid() && Sys_GetUid() != ROOT_UID)
+    if (target->uid != Sys_GetUid() && Sys_GetUid() != ROOT_UID)
     {
         status = OBOS_STATUS_ACCESS_DENIED;
         goto fail;
@@ -3048,9 +3048,9 @@ obos_status Sys_FChownAt(handle dirfd, const char *upathname, uid owner, gid gro
         goto fail;
 
     if (owner != -1)
-        target->owner_uid = owner;
+        target->uid = owner;
     if (group != -1)
-        target->group_uid = group;
+        target->gid = group;
 
     fail:
     Free(OBOS_KernelAllocator, pathname, sz_path);
diff --git a/src/oboskrnl/vfs/pipe.c b/src/oboskrnl/vfs/pipe.c
index c901e4cf..dad9b4c5 100644
--- a/src/oboskrnl/vfs/pipe.c
+++ b/src/oboskrnl/vfs/pipe.c
@@ -442,8 +442,8 @@ obos_status Vfs_CreateNamedPipe(file_perm perm, gid group_uid, uid owner_uid, di
     dirent* ent = Vfs_Calloc(1, sizeof(dirent));
     vnode* vn = Vfs_Calloc(1, sizeof(vnode));
     desc->vn = vn;
-    vn->owner_uid = owner_uid;
-    vn->group_uid = group_uid;
+    vn->uid = owner_uid;
+    vn->gid = group_uid;
     vn->desc = (uintptr_t)desc;
     vn->perm = perm;
     vn->vtype = VNODE_TYPE_FIFO;
diff --git a/src/oboskrnl/vfs/vnode.h b/src/oboskrnl/vfs/vnode.h
index d0475e83..ec91ee5e 100644
--- a/src/oboskrnl/vfs/vnode.h
+++ b/src/oboskrnl/vfs/vnode.h
@@ -90,8 +90,8 @@ typedef struct vnode
     size_t refs;
     file_perm perm;
     size_t filesize; // filesize.
-    uid owner_uid; // the owner's UID.
-    gid group_uid; // the group's GID.
+    uid uid; // the owner's UID.
+    gid gid; // the group's GID.
     dev_desc desc; // the cached device descriptor.
     fd_list opened;
     size_t nMappedRegions;