Kernel: Make InodeWatcher::crate API OOM safe

3 files changed, 21 insertions, 7 deletions

diff --git a/Kernel/FileSystem/InodeWatcher.cpp b/Kernel/FileSystem/InodeWatcher.cpp
index ea66d7cc3a..fb7c36739a 100644
--- a/Kernel/FileSystem/InodeWatcher.cpp
+++ b/Kernel/FileSystem/InodeWatcher.cpp
@@ -12,9 +12,12 @@
 
 namespace Kernel {
 
-NonnullRefPtr<InodeWatcher> InodeWatcher::create()
+KResultOr<NonnullRefPtr<InodeWatcher>> InodeWatcher::create()
 {
-    return adopt_ref(*new InodeWatcher);
+    auto watcher = adopt_ref_if_nonnull(new InodeWatcher);
+    if (watcher)
+        return watcher.release_nonnull();
+    return ENOMEM;
 }
 
 InodeWatcher::~InodeWatcher()
@@ -120,7 +123,11 @@ KResultOr<int> InodeWatcher::register_inode(Inode& inode, unsigned event_mask)
             m_wd_counter = 1;
     } while (m_wd_to_watches.find(wd) != m_wd_to_watches.end());
 
-    auto description = WatchDescription::create(wd, inode, event_mask);
+    auto description_or_error = WatchDescription::create(wd, inode, event_mask);
+    if (description_or_error.is_error())
+        return description_or_error.error();
+
+    auto description = description_or_error.release_value();
     m_inode_to_watches.set(inode.identifier(), description.ptr());
     m_wd_to_watches.set(wd, move(description));
 
diff --git a/Kernel/FileSystem/InodeWatcher.h b/Kernel/FileSystem/InodeWatcher.h
index f429e17ab4..7a7c68d2dd 100644
--- a/Kernel/FileSystem/InodeWatcher.h
+++ b/Kernel/FileSystem/InodeWatcher.h
@@ -25,9 +25,12 @@ struct WatchDescription {
     Inode& inode;
     unsigned event_mask;
 
-    static NonnullOwnPtr<WatchDescription> create(int wd, Inode& inode, unsigned event_mask)
+    static KResultOr<NonnullOwnPtr<WatchDescription>> create(int wd, Inode& inode, unsigned event_mask)
     {
-        return adopt_own(*new WatchDescription(wd, inode, event_mask));
+        auto description = adopt_own_if_nonnull(new WatchDescription(wd, inode, event_mask));
+        if (description)
+            return description.release_nonnull();
+        return ENOMEM;
     }
 
 private:
@@ -41,7 +44,7 @@ private:
 
 class InodeWatcher final : public File {
 public:
-    static NonnullRefPtr<InodeWatcher> create();
+    static KResultOr<NonnullRefPtr<InodeWatcher>> create();
     virtual ~InodeWatcher() override;
 
     virtual bool can_read(const FileDescription&, size_t) const override;
diff --git a/Kernel/Syscalls/inode_watcher.cpp b/Kernel/Syscalls/inode_watcher.cpp
index fc9e878acb..537301974f 100644
--- a/Kernel/Syscalls/inode_watcher.cpp
+++ b/Kernel/Syscalls/inode_watcher.cpp
@@ -21,7 +21,11 @@ KResultOr<int> Process::sys$create_inode_watcher(u32 flags)
     if (fd < 0)
         return fd;
 
-    auto description_or_error = FileDescription::create(*InodeWatcher::create());
+    auto watcher_or_error = InodeWatcher::create();
+    if (watcher_or_error.is_error())
+        return watcher_or_error.error();
+
+    auto description_or_error = FileDescription::create(*watcher_or_error.value());
     if (description_or_error.is_error())
         return description_or_error.error();