Kernel: Add a basic chroot() syscall :^)

The chroot() syscall now allows the superuser to isolate a process into
a specific subtree of the filesystem. This is not strictly permanent,
as it is also possible for a superuser to break *out* of a chroot, but
it is a useful mechanism for isolating unprivileged processes.

The VFS now uses the current process's root_directory() as the root for
path resolution purposes. The root directory is stored as an uncached
Custody in the Process object.

1 files changed, 2 insertions, 0 deletions

diff --git a/Kernel/init.cpp b/Kernel/init.cpp
index b7df3d8691..8022facf29 100644
--- a/Kernel/init.cpp
+++ b/Kernel/init.cpp
@@ -145,6 +145,8 @@ VFS* vfs;
         hang();
     }
 
+    current->process().set_root_directory(vfs->root_custody());
+
     dbgprintf("Load ksyms\n");
     load_ksyms();
     dbgprintf("Loaded ksyms\n");