From 0f7fe1eb08851e481ee760528362b71d5124eaf5 Mon Sep 17 00:00:00 2001
From: Brian Gianforcaro <bgianf@serenityos.org>
Date: Wed, 29 Dec 2021 00:16:27 -0800
Subject: [PATCH] Kernel: Use Process::require_no_promises instead of
 REQUIRE_NO_PROMISES

This change lays the foundation for making the require_promise return
an error hand handling the process abort outside of the syscall
implementations, to avoid cases where we would leak resources.

It also has the advantage that it makes removes a gs pointer read
to look up the current thread, then process for every syscall. We
can instead go through the Process this pointer in most cases.
---
 Kernel/Syscalls/hostname.cpp  | 3 ++-
 Kernel/Syscalls/mount.cpp     | 4 ++--
 Kernel/Syscalls/profiling.cpp | 6 +++---
 Kernel/Syscalls/purge.cpp     | 2 +-
 4 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/Kernel/Syscalls/hostname.cpp b/Kernel/Syscalls/hostname.cpp
index d5698467b3..ee087923fa 100644
--- a/Kernel/Syscalls/hostname.cpp
+++ b/Kernel/Syscalls/hostname.cpp
@@ -25,7 +25,8 @@ ErrorOr<FlatPtr> Process::sys$gethostname(Userspace<char*> buffer, size_t size)
 ErrorOr<FlatPtr> Process::sys$sethostname(Userspace<const char*> buffer, size_t length)
 {
     VERIFY_NO_PROCESS_BIG_LOCK(this)
-    REQUIRE_NO_PROMISES;
+    require_no_promises();
+
     if (!is_superuser())
         return EPERM;
     if (length > 64)
diff --git a/Kernel/Syscalls/mount.cpp b/Kernel/Syscalls/mount.cpp
index 4b12e8034b..0fd05ae7a3 100644
--- a/Kernel/Syscalls/mount.cpp
+++ b/Kernel/Syscalls/mount.cpp
@@ -21,10 +21,10 @@ namespace Kernel {
 ErrorOr<FlatPtr> Process::sys$mount(Userspace<const Syscall::SC_mount_params*> user_params)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
+    require_no_promises();
     if (!is_superuser())
         return EPERM;
 
-    REQUIRE_NO_PROMISES;
     auto params = TRY(copy_typed_from_user(user_params));
 
     auto source_fd = params.source_fd;
@@ -120,7 +120,7 @@ ErrorOr<FlatPtr> Process::sys$umount(Userspace<const char*> user_mountpoint, siz
     if (!is_superuser())
         return EPERM;
 
-    REQUIRE_NO_PROMISES;
+    require_no_promises();
 
     auto mountpoint = TRY(get_syscall_path_argument(user_mountpoint, mountpoint_length));
     auto custody = TRY(VirtualFileSystem::the().resolve_path(mountpoint->view(), current_directory()));
diff --git a/Kernel/Syscalls/profiling.cpp b/Kernel/Syscalls/profiling.cpp
index 5376772bc6..ed54d9ea15 100644
--- a/Kernel/Syscalls/profiling.cpp
+++ b/Kernel/Syscalls/profiling.cpp
@@ -19,7 +19,7 @@ u64 g_profiling_event_mask;
 ErrorOr<FlatPtr> Process::sys$profiling_enable(pid_t pid, u64 event_mask)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
-    REQUIRE_NO_PROMISES;
+    require_no_promises();
 
     if (pid == -1) {
         if (!is_superuser())
@@ -69,7 +69,7 @@ ErrorOr<FlatPtr> Process::sys$profiling_enable(pid_t pid, u64 event_mask)
 ErrorOr<FlatPtr> Process::sys$profiling_disable(pid_t pid)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
-    REQUIRE_NO_PROMISES;
+    require_no_promises();
 
     if (pid == -1) {
         if (!is_superuser())
@@ -99,7 +99,7 @@ ErrorOr<FlatPtr> Process::sys$profiling_disable(pid_t pid)
 ErrorOr<FlatPtr> Process::sys$profiling_free_buffer(pid_t pid)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
-    REQUIRE_NO_PROMISES;
+    require_no_promises();
 
     if (pid == -1) {
         if (!is_superuser())
diff --git a/Kernel/Syscalls/purge.cpp b/Kernel/Syscalls/purge.cpp
index 0c52501fc2..722c67166f 100644
--- a/Kernel/Syscalls/purge.cpp
+++ b/Kernel/Syscalls/purge.cpp
@@ -15,7 +15,7 @@ namespace Kernel {
 ErrorOr<FlatPtr> Process::sys$purge(int mode)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
-    REQUIRE_NO_PROMISES;
+    require_no_promises();
     if (!is_superuser())
         return EPERM;
     size_t purged_page_count = 0;