Kernel+Userland: Introduce a new way to reboot and poweroff the machine

This change removes the halt and reboot syscalls, and create a new
mechanism to change the power state of the machine.
Instead of how power state was changed until now, put a SysFS node as
writable only for the superuser, that with a defined value, can result
in either reboot or poweroff.
In the future, a power group can be assigned to this node (which will be
the GroupID responsible for power management).

This opens an opportunity to permit to shutdown/reboot without superuser
permissions, so in the future, a userspace daemon can take control of
this node to perform power management operations without superuser
permissions, if we enforce different UserID/GroupID on that node.

2 files changed, 0 insertions, 14 deletions

diff --git a/Userland/Libraries/LibC/unistd.cpp b/Userland/Libraries/LibC/unistd.cpp
index 7f7aa566c4..a902910424 100644
--- a/Userland/Libraries/LibC/unistd.cpp
+++ b/Userland/Libraries/LibC/unistd.cpp
@@ -715,18 +715,6 @@ int fsync(int fd)
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
 
-int halt()
-{
-    int rc = syscall(SC_halt);
-    __RETURN_WITH_ERRNO(rc, rc, -1);
-}
-
-int reboot()
-{
-    int rc = syscall(SC_reboot);
-    __RETURN_WITH_ERRNO(rc, rc, -1);
-}
-
 int mount(int source_fd, const char* target, const char* fs_type, int flags)
 {
     if (!target || !fs_type) {
diff --git a/Userland/Libraries/LibC/unistd.h b/Userland/Libraries/LibC/unistd.h
index 2cdfb4df5c..d738aaa32d 100644
--- a/Userland/Libraries/LibC/unistd.h
+++ b/Userland/Libraries/LibC/unistd.h
@@ -108,8 +108,6 @@ int chown(const char* pathname, uid_t, gid_t);
 int fchown(int fd, uid_t, gid_t);
 int ftruncate(int fd, off_t length);
 int truncate(const char* path, off_t length);
-int halt();
-int reboot();
 int mount(int source_fd, const char* target, const char* fs_type, int flags);
 int umount(const char* mountpoint);
 int pledge(const char* promises, const char* execpromises);