Kernel+LibC+LibCore: Implement the unlinkat(2) syscall

3 files changed, 21 insertions, 3 deletions

diff --git a/Kernel/API/POSIX/fcntl.h b/Kernel/API/POSIX/fcntl.h
index b28cefb678..2a8bdfca5c 100644
--- a/Kernel/API/POSIX/fcntl.h
+++ b/Kernel/API/POSIX/fcntl.h
@@ -46,6 +46,7 @@ extern "C" {
 
 #define AT_FDCWD -100
 #define AT_SYMLINK_NOFOLLOW 0x100
+#define AT_REMOVEDIR 0x200
 
 struct flock {
     short l_type;
diff --git a/Kernel/Process.h b/Kernel/Process.h
index 0f83fee862..195ef0b3d9 100644
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@@ -354,7 +354,7 @@ public:
     ErrorOr<FlatPtr> sys$times(Userspace<tms*>);
     ErrorOr<FlatPtr> sys$utime(Userspace<char const*> pathname, size_t path_length, Userspace<const struct utimbuf*>);
     ErrorOr<FlatPtr> sys$link(Userspace<Syscall::SC_link_params const*>);
-    ErrorOr<FlatPtr> sys$unlink(Userspace<char const*> pathname, size_t path_length);
+    ErrorOr<FlatPtr> sys$unlink(int dirfd, Userspace<char const*> pathname, size_t path_length, int flags);
     ErrorOr<FlatPtr> sys$symlink(Userspace<Syscall::SC_symlink_params const*>);
     ErrorOr<FlatPtr> sys$rmdir(Userspace<char const*> pathname, size_t path_length);
     ErrorOr<FlatPtr> sys$mount(Userspace<Syscall::SC_mount_params const*>);
diff --git a/Kernel/Syscalls/unlink.cpp b/Kernel/Syscalls/unlink.cpp
index 80c89518db..582b1bea58 100644
--- a/Kernel/Syscalls/unlink.cpp
+++ b/Kernel/Syscalls/unlink.cpp
@@ -10,12 +10,29 @@
 
 namespace Kernel {
 
-ErrorOr<FlatPtr> Process::sys$unlink(Userspace<char const*> user_path, size_t path_length)
+ErrorOr<FlatPtr> Process::sys$unlink(int dirfd, Userspace<char const*> user_path, size_t path_length, int flags)
 {
     VERIFY_NO_PROCESS_BIG_LOCK(this)
     TRY(require_promise(Pledge::cpath));
     auto path = TRY(get_syscall_path_argument(user_path, path_length));
-    TRY(VirtualFileSystem::the().unlink(path->view(), current_directory()));
+
+    if (flags & ~AT_REMOVEDIR)
+        return Error::from_errno(EINVAL);
+
+    RefPtr<Custody> base;
+    if (dirfd == AT_FDCWD) {
+        base = current_directory();
+    } else {
+        auto base_description = TRY(open_file_description(dirfd));
+        if (!base_description->custody())
+            return Error::from_errno(EINVAL);
+        base = base_description->custody();
+    }
+
+    if (flags & AT_REMOVEDIR)
+        TRY(VirtualFileSystem::the().rmdir(path->view(), *base));
+    else
+        TRY(VirtualFileSystem::the().unlink(path->view(), *base));
     return 0;
 }