Kernel: Make file description lookup return KResultOr

Instead of checking it at every call site (to generate EBADF), we make
file_description(fd) return a KResultOr<NonnullRefPtr<FileDescription>>.

This allows us to wrap all the calls in TRY(). :^)

The only place that got a little bit messier from this is sys$mount(),
and there's a whole bunch of things there in need of cleanup.

24 files changed, 62 insertions, 155 deletions

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 949a7c5f71..2c5fdf6f4e 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -452,14 +452,17 @@ Process::FileDescriptionAndFlags& Process::FileDescriptions::at(size_t i)
     return m_fds_metadatas[i];
 }
 
-RefPtr<FileDescription> Process::FileDescriptions::file_description(int fd) const
+KResultOr<NonnullRefPtr<FileDescription>> Process::FileDescriptions::file_description(int fd) const
 {
     SpinlockLocker lock(m_fds_lock);
     if (fd < 0)
-        return nullptr;
-    if (static_cast<size_t>(fd) < m_fds_metadatas.size())
-        return m_fds_metadatas[fd].description();
-    return nullptr;
+        return EBADF;
+    if (static_cast<size_t>(fd) >= m_fds_metadatas.size())
+        return EBADF;
+    RefPtr description = m_fds_metadatas[fd].description();
+    if (!description)
+        return EBADF;
+    return description.release_nonnull();
 }
 
 void Process::FileDescriptions::enumerate(Function<void(const FileDescriptionAndFlags&)> callback) const
diff --git a/Kernel/Process.h b/Kernel/Process.h
index 72cbd88580..6eda1f0d1a 100644
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@@ -676,8 +676,7 @@ public:
             m_fds_metadatas.clear();
         }
 
-        // FIXME: Consider to remove this somehow
-        RefPtr<FileDescription> file_description(int fd) const;
+        KResultOr<NonnullRefPtr<FileDescription>> file_description(int fd) const;
 
     private:
         FileDescriptions() = default;
diff --git a/Kernel/ProcessSpecificExposed.cpp b/Kernel/ProcessSpecificExposed.cpp
index dbd9a716a5..1f6adcaaf7 100644
--- a/Kernel/ProcessSpecificExposed.cpp
+++ b/Kernel/ProcessSpecificExposed.cpp
@@ -79,9 +79,7 @@ KResultOr<NonnullRefPtr<Inode>> Process::lookup_stacks_directory(const ProcFS& p
 
 KResultOr<size_t> Process::procfs_get_file_description_link(unsigned fd, KBufferBuilder& builder) const
 {
-    auto file_description = m_fds.file_description(fd);
-    if (!file_description)
-        return EBADF;
+    auto file_description = TRY(m_fds.file_description(fd));
     auto data = file_description->absolute_path();
     builder.append(data);
     return data.length();
diff --git a/Kernel/Syscalls/chdir.cpp b/Kernel/Syscalls/chdir.cpp
index 5b5da7acfc..7b200e9f25 100644
--- a/Kernel/Syscalls/chdir.cpp
+++ b/Kernel/Syscalls/chdir.cpp
@@ -23,16 +23,11 @@ KResultOr<FlatPtr> Process::sys$fchdir(int fd)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
     REQUIRE_PROMISE(stdio);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
-
+    auto description = TRY(fds().file_description(fd));
     if (!description->is_directory())
         return ENOTDIR;
-
     if (!description->metadata().may_execute(*this))
         return EACCES;
-
     m_cwd = description->custody();
     return 0;
 }
diff --git a/Kernel/Syscalls/chmod.cpp b/Kernel/Syscalls/chmod.cpp
index f7fd0c439d..8cc9b8a863 100644
--- a/Kernel/Syscalls/chmod.cpp
+++ b/Kernel/Syscalls/chmod.cpp
@@ -22,9 +22,7 @@ KResultOr<FlatPtr> Process::sys$fchmod(int fd, mode_t mode)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
     REQUIRE_PROMISE(fattr);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     return description->chmod(mode);
 }
 
diff --git a/Kernel/Syscalls/chown.cpp b/Kernel/Syscalls/chown.cpp
index 5c0803bea3..1a014e07fb 100644
--- a/Kernel/Syscalls/chown.cpp
+++ b/Kernel/Syscalls/chown.cpp
@@ -13,9 +13,7 @@ KResultOr<FlatPtr> Process::sys$fchown(int fd, UserID uid, GroupID gid)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
     REQUIRE_PROMISE(chown);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     return description->chown(uid, gid);
 }
 
diff --git a/Kernel/Syscalls/dup2.cpp b/Kernel/Syscalls/dup2.cpp
index b836f1282e..3ccef1dcb9 100644
--- a/Kernel/Syscalls/dup2.cpp
+++ b/Kernel/Syscalls/dup2.cpp
@@ -13,16 +13,14 @@ KResultOr<FlatPtr> Process::sys$dup2(int old_fd, int new_fd)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
     REQUIRE_PROMISE(stdio);
-    auto description = fds().file_description(old_fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(old_fd));
     if (old_fd == new_fd)
         return new_fd;
     if (new_fd < 0 || static_cast<size_t>(new_fd) >= fds().max_open())
         return EINVAL;
     if (!m_fds.m_fds_metadatas[new_fd].is_allocated())
         m_fds.m_fds_metadatas[new_fd].allocate();
-    m_fds[new_fd].set(*description);
+    m_fds[new_fd].set(move(description));
     return new_fd;
 }
 
diff --git a/Kernel/Syscalls/fcntl.cpp b/Kernel/Syscalls/fcntl.cpp
index 33265302ff..af54a9ff2e 100644
--- a/Kernel/Syscalls/fcntl.cpp
+++ b/Kernel/Syscalls/fcntl.cpp
@@ -15,9 +15,7 @@ KResultOr<FlatPtr> Process::sys$fcntl(int fd, int cmd, u32 arg)
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
     REQUIRE_PROMISE(stdio);
     dbgln_if(IO_DEBUG, "sys$fcntl: fd={}, cmd={}, arg={}", fd, cmd, arg);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     // NOTE: The FD flags are not shared between FileDescription objects.
     //       This means that dup() doesn't copy the FD_CLOEXEC flag!
     switch (cmd) {
diff --git a/Kernel/Syscalls/ftruncate.cpp b/Kernel/Syscalls/ftruncate.cpp
index b01780c848..f0a4e148d9 100644
--- a/Kernel/Syscalls/ftruncate.cpp
+++ b/Kernel/Syscalls/ftruncate.cpp
@@ -17,9 +17,7 @@ KResultOr<FlatPtr> Process::sys$ftruncate(int fd, Userspace<off_t*> userspace_le
     TRY(copy_from_user(&length, userspace_length));
     if (length < 0)
         return EINVAL;
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     if (!description->is_writable())
         return EBADF;
     return description->truncate(static_cast<u64>(length));
diff --git a/Kernel/Syscalls/get_dir_entries.cpp b/Kernel/Syscalls/get_dir_entries.cpp
index 2f98386858..6cbd6c6fc7 100644
--- a/Kernel/Syscalls/get_dir_entries.cpp
+++ b/Kernel/Syscalls/get_dir_entries.cpp
@@ -15,9 +15,7 @@ KResultOr<FlatPtr> Process::sys$get_dir_entries(int fd, Userspace<void*> user_bu
     REQUIRE_PROMISE(stdio);
     if (user_size > NumericLimits<ssize_t>::max())
         return EINVAL;
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     auto buffer = UserOrKernelBuffer::for_user_buffer(user_buffer, static_cast<size_t>(user_size));
     if (!buffer.has_value())
         return EFAULT;
diff --git a/Kernel/Syscalls/inode_watcher.cpp b/Kernel/Syscalls/inode_watcher.cpp
index 9623634df3..17d7039018 100644
--- a/Kernel/Syscalls/inode_watcher.cpp
+++ b/Kernel/Syscalls/inode_watcher.cpp
@@ -48,9 +48,7 @@ KResultOr<FlatPtr> Process::sys$inode_watcher_add_watch(Userspace<const Syscall:
     REQUIRE_PROMISE(rpath);
     auto params = TRY(copy_typed_from_user(user_params));
 
-    auto description = fds().file_description(params.fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(params.fd));
     if (!description->is_inode_watcher())
         return EBADF;
     auto inode_watcher = description->inode_watcher();
@@ -76,9 +74,7 @@ KResultOr<FlatPtr> Process::sys$inode_watcher_add_watch(Userspace<const Syscall:
 KResultOr<FlatPtr> Process::sys$inode_watcher_remove_watch(int fd, int wd)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     if (!description->is_inode_watcher())
         return EBADF;
     auto inode_watcher = description->inode_watcher();
diff --git a/Kernel/Syscalls/ioctl.cpp b/Kernel/Syscalls/ioctl.cpp
index 5a2b740b08..9f9582d6e1 100644
--- a/Kernel/Syscalls/ioctl.cpp
+++ b/Kernel/Syscalls/ioctl.cpp
@@ -13,9 +13,7 @@ namespace Kernel {
 KResultOr<FlatPtr> Process::sys$ioctl(int fd, unsigned request, FlatPtr arg)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     if (request == FIONBIO) {
         description->set_blocking(arg == 0);
         return KSuccess;
diff --git a/Kernel/Syscalls/lseek.cpp b/Kernel/Syscalls/lseek.cpp
index a25cd63072..b2c1ddedb0 100644
--- a/Kernel/Syscalls/lseek.cpp
+++ b/Kernel/Syscalls/lseek.cpp
@@ -13,9 +13,7 @@ KResultOr<FlatPtr> Process::sys$lseek(int fd, Userspace<off_t*> userspace_offset
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     REQUIRE_PROMISE(stdio);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     off_t offset;
     TRY(copy_from_user(&offset, userspace_offset));
     auto seek_result = TRY(description->seek(offset, whence));
diff --git a/Kernel/Syscalls/mmap.cpp b/Kernel/Syscalls/mmap.cpp
index 92e6340a81..7b0e691fb5 100644
--- a/Kernel/Syscalls/mmap.cpp
+++ b/Kernel/Syscalls/mmap.cpp
@@ -223,9 +223,7 @@ KResultOr<FlatPtr> Process::sys$mmap(Userspace<const Syscall::SC_mmap_params*> u
             return EINVAL;
         if (static_cast<size_t>(offset) & ~PAGE_MASK)
             return EINVAL;
-        auto description = fds().file_description(fd);
-        if (!description)
-            return EBADF;
+        auto description = TRY(fds().file_description(fd));
         if (description->is_directory())
             return ENODEV;
         // Require read access even when read protection is not requested.
diff --git a/Kernel/Syscalls/mount.cpp b/Kernel/Syscalls/mount.cpp
index 5885d2e28a..c1dffb76cd 100644
--- a/Kernel/Syscalls/mount.cpp
+++ b/Kernel/Syscalls/mount.cpp
@@ -32,8 +32,8 @@ KResultOr<FlatPtr> Process::sys$mount(Userspace<const Syscall::SC_mount_params*>
     auto fs_type_string = TRY(try_copy_kstring_from_user(params.fs_type));
     auto fs_type = fs_type_string->view();
 
-    auto description = fds().file_description(source_fd);
-    if (!description.is_null())
+    auto description_or_error = fds().file_description(source_fd);
+    if (!description_or_error.is_error())
         dbgln("mount {}: source fd {} @ {}", fs_type, source_fd, target);
     else
         dbgln("mount {} @ {}", fs_type, target);
@@ -47,8 +47,9 @@ KResultOr<FlatPtr> Process::sys$mount(Userspace<const Syscall::SC_mount_params*>
 
     if (params.flags & MS_BIND) {
         // We're doing a bind mount.
-        if (description.is_null())
-            return EBADF;
+        if (description_or_error.is_error())
+            return description_or_error.error();
+        auto description = description_or_error.release_value();
         if (!description->custody()) {
             // We only support bind-mounting inodes, not arbitrary files.
             return ENODEV;
@@ -59,8 +60,9 @@ KResultOr<FlatPtr> Process::sys$mount(Userspace<const Syscall::SC_mount_params*>
     RefPtr<FileSystem> fs;
 
     if (fs_type == "ext2"sv || fs_type == "Ext2FS"sv) {
-        if (description.is_null())
+        if (description_or_error.is_error())
             return EBADF;
+        auto description = description_or_error.release_value();
         if (!description->file().is_block_device())
             return ENOTBLK;
         if (!description->file().is_seekable()) {
@@ -72,9 +74,9 @@ KResultOr<FlatPtr> Process::sys$mount(Userspace<const Syscall::SC_mount_params*>
 
         fs = Ext2FS::create(*description);
     } else if (fs_type == "9p"sv || fs_type == "Plan9FS"sv) {
-        if (description.is_null())
+        if (description_or_error.is_error())
             return EBADF;
-
+        auto description = description_or_error.release_value();
         fs = Plan9FS::create(*description);
     } else if (fs_type == "proc"sv || fs_type == "ProcFS"sv) {
         fs = TRY(ProcFS::try_create());
@@ -87,15 +89,14 @@ KResultOr<FlatPtr> Process::sys$mount(Userspace<const Syscall::SC_mount_params*>
     } else if (fs_type == "tmp"sv || fs_type == "TmpFS"sv) {
         fs = TmpFS::create();
     } else if (fs_type == "iso9660"sv || fs_type == "ISO9660FS"sv) {
-        if (description.is_null())
+        if (description_or_error.is_error())
             return EBADF;
+        auto description = description_or_error.release_value();
         if (!description->file().is_seekable()) {
             dbgln("mount: this is not a seekable file");
             return ENODEV;
         }
-
         dbgln("mount: attempting to mount {} on {}", description->absolute_path(), target);
-
         fs = TRY(ISO9660FS::try_create(*description));
     } else {
         return ENODEV;
diff --git a/Kernel/Syscalls/open.cpp b/Kernel/Syscalls/open.cpp
index 86775e436c..100a077931 100644
--- a/Kernel/Syscalls/open.cpp
+++ b/Kernel/Syscalls/open.cpp
@@ -46,9 +46,7 @@ KResultOr<FlatPtr> Process::sys$open(Userspace<const Syscall::SC_open_params*> u
     if (dirfd == AT_FDCWD) {
         base = current_directory();
     } else {
-        auto base_description = fds().file_description(dirfd);
-        if (!base_description)
-            return EBADF;
+        auto base_description = TRY(fds().file_description(dirfd));
         if (!base_description->is_directory())
             return ENOTDIR;
         if (!base_description->custody())
@@ -70,10 +68,7 @@ KResultOr<FlatPtr> Process::sys$close(int fd)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     REQUIRE_PROMISE(stdio);
-    auto description = fds().file_description(fd);
-    dbgln_if(IO_DEBUG, "sys$close({}) {}", fd, description.ptr());
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     auto result = description->close();
     m_fds[fd] = {};
     return result;
diff --git a/Kernel/Syscalls/read.cpp b/Kernel/Syscalls/read.cpp
index 19bb1e1db8..99308cbab5 100644
--- a/Kernel/Syscalls/read.cpp
+++ b/Kernel/Syscalls/read.cpp
@@ -34,13 +34,9 @@ KResultOr<FlatPtr> Process::sys$readv(int fd, Userspace<const struct iovec*> iov
             return EINVAL;
     }
 
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
-
+    auto description = TRY(fds().file_description(fd));
     if (!description->is_readable())
         return EBADF;
-
     if (description->is_directory())
         return EISDIR;
 
@@ -75,9 +71,7 @@ KResultOr<FlatPtr> Process::sys$read(int fd, Userspace<u8*> buffer, size_t size)
     if (size > NumericLimits<ssize_t>::max())
         return EINVAL;
     dbgln_if(IO_DEBUG, "sys$read({}, {}, {})", fd, buffer.ptr(), size);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     if (!description->is_readable())
         return EBADF;
     if (description->is_directory())
diff --git a/Kernel/Syscalls/select.cpp b/Kernel/Syscalls/select.cpp
index 1e3d4b0b31..9ece4b8463 100644
--- a/Kernel/Syscalls/select.cpp
+++ b/Kernel/Syscalls/select.cpp
@@ -73,12 +73,8 @@ KResultOr<FlatPtr> Process::sys$select(Userspace<const Syscall::SC_select_params
         if (block_flags == BlockFlags::None)
             continue;
 
-        auto description = fds().file_description(fd);
-        if (!description) {
-            dbgln("sys$select: Bad fd number {}", fd);
-            return EBADF;
-        }
-        if (!fds_info.try_append({ description.release_nonnull(), block_flags }))
+        auto description = TRY(fds().file_description(fd));
+        if (!fds_info.try_append({ move(description), block_flags }))
             return ENOMEM;
         if (!selected_fds.try_append(fd))
             return ENOMEM;
@@ -162,11 +158,7 @@ KResultOr<FlatPtr> Process::sys$poll(Userspace<const Syscall::SC_poll_params*> u
     Thread::SelectBlocker::FDVector fds_info;
     for (size_t i = 0; i < params.nfds; i++) {
         auto& pfd = fds_copy[i];
-        auto description = fds().file_description(pfd.fd);
-        if (!description) {
-            dbgln("sys$poll: Bad fd number {}", pfd.fd);
-            return EBADF;
-        }
+        auto description = TRY(fds().file_description(pfd.fd));
         BlockFlags block_flags = BlockFlags::Exception; // always want POLLERR, POLLHUP, POLLNVAL
         if (pfd.events & POLLIN)
             block_flags |= BlockFlags::Read;
@@ -174,7 +166,7 @@ KResultOr<FlatPtr> Process::sys$poll(Userspace<const Syscall::SC_poll_params*> u
             block_flags |= BlockFlags::Write;
         if (pfd.events & POLLPRI)
             block_flags |= BlockFlags::ReadPriority;
-        if (!fds_info.try_append({ description.release_nonnull(), block_flags }))
+        if (!fds_info.try_append({ move(description), block_flags }))
             return ENOMEM;
     }
 
diff --git a/Kernel/Syscalls/sendfd.cpp b/Kernel/Syscalls/sendfd.cpp
index fd82027f4f..6c0fed3cac 100644
--- a/Kernel/Syscalls/sendfd.cpp
+++ b/Kernel/Syscalls/sendfd.cpp
@@ -14,9 +14,7 @@ KResultOr<FlatPtr> Process::sys$sendfd(int sockfd, int fd)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     REQUIRE_PROMISE(sendfd);
-    auto socket_description = fds().file_description(sockfd);
-    if (!socket_description)
-        return EBADF;
+    auto socket_description = TRY(fds().file_description(sockfd));
     if (!socket_description->is_socket())
         return ENOTSOCK;
     auto& socket = *socket_description->socket();
@@ -25,10 +23,7 @@ KResultOr<FlatPtr> Process::sys$sendfd(int sockfd, int fd)
     if (!socket.is_connected())
         return ENOTCONN;
 
-    auto passing_descriptor = fds().file_description(fd);
-    if (!passing_descriptor)
-        return EBADF;
-
+    auto passing_descriptor = TRY(fds().file_description(fd));
     auto& local_socket = static_cast<LocalSocket&>(socket);
     return local_socket.sendfd(*socket_description, *passing_descriptor);
 }
@@ -37,9 +32,7 @@ KResultOr<FlatPtr> Process::sys$recvfd(int sockfd, int options)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     REQUIRE_PROMISE(recvfd);
-    auto socket_description = fds().file_description(sockfd);
-    if (!socket_description)
-        return EBADF;
+    auto socket_description = TRY(fds().file_description(sockfd));
     if (!socket_description->is_socket())
         return ENOTSOCK;
     auto& socket = *socket_description->socket();
diff --git a/Kernel/Syscalls/socket.cpp b/Kernel/Syscalls/socket.cpp
index 179562784d..2794f907b6 100644
--- a/Kernel/Syscalls/socket.cpp
+++ b/Kernel/Syscalls/socket.cpp
@@ -48,9 +48,7 @@ KResultOr<FlatPtr> Process::sys$socket(int domain, int type, int protocol)
 KResultOr<FlatPtr> Process::sys$bind(int sockfd, Userspace<const sockaddr*> address, socklen_t address_length)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
-    auto description = fds().file_description(sockfd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(sockfd));
     if (!description->is_socket())
         return ENOTSOCK;
     auto& socket = *description->socket();
@@ -63,9 +61,7 @@ KResultOr<FlatPtr> Process::sys$listen(int sockfd, int backlog)
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     if (backlog < 0)
         return EINVAL;
-    auto description = fds().file_description(sockfd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(sockfd));
     if (!description->is_socket())
         return ENOTSOCK;
     auto& socket = *description->socket();
@@ -92,9 +88,7 @@ KResultOr<FlatPtr> Process::sys$accept4(Userspace<const Syscall::SC_accept4_para
     }
 
     auto fd_allocation = TRY(m_fds.allocate());
-    auto accepting_socket_description = fds().file_description(accepting_socket_fd);
-    if (!accepting_socket_description)
-        return EBADF;
+    auto accepting_socket_description = TRY(fds().file_description(accepting_socket_fd));
     if (!accepting_socket_description->is_socket())
         return ENOTSOCK;
     auto& socket = *accepting_socket_description->socket();
@@ -138,15 +132,11 @@ KResultOr<FlatPtr> Process::sys$accept4(Userspace<const Syscall::SC_accept4_para
 KResultOr<FlatPtr> Process::sys$connect(int sockfd, Userspace<const sockaddr*> user_address, socklen_t user_address_size)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
-    auto description = fds().file_description(sockfd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(sockfd));
     if (!description->is_socket())
         return ENOTSOCK;
-
     auto& socket = *description->socket();
     REQUIRE_PROMISE_FOR_SOCKET_DOMAIN(socket.domain());
-
     return socket.connect(*description, user_address, user_address_size, description->is_blocking() ? ShouldBlock::Yes : ShouldBlock::No);
 }
 
@@ -156,12 +146,9 @@ KResultOr<FlatPtr> Process::sys$shutdown(int sockfd, int how)
     REQUIRE_PROMISE(stdio);
     if (how & ~SHUT_RDWR)
         return EINVAL;
-    auto description = fds().file_description(sockfd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(sockfd));
     if (!description->is_socket())
         return ENOTSOCK;
-
     auto& socket = *description->socket();
     REQUIRE_PROMISE_FOR_SOCKET_DOMAIN(socket.domain());
     return socket.shutdown(how);
@@ -186,9 +173,7 @@ KResultOr<FlatPtr> Process::sys$sendmsg(int sockfd, Userspace<const struct msghd
     Userspace<const sockaddr*> user_addr((FlatPtr)msg.msg_name);
     socklen_t addr_length = msg.msg_namelen;
 
-    auto description = fds().file_description(sockfd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(sockfd));
     if (!description->is_socket())
         return ENOTSOCK;
     auto& socket = *description->socket();
@@ -222,9 +207,7 @@ KResultOr<FlatPtr> Process::sys$recvmsg(int sockfd, Userspace<struct msghdr*> us
     Userspace<sockaddr*> user_addr((FlatPtr)msg.msg_name);
     Userspace<socklen_t*> user_addr_length(msg.msg_name ? (FlatPtr)&user_msg.unsafe_userspace_ptr()->msg_namelen : 0);
 
-    auto description = fds().file_description(sockfd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(sockfd));
     if (!description->is_socket())
         return ENOTSOCK;
     auto& socket = *description->socket();
@@ -282,10 +265,7 @@ KResult Process::get_sock_or_peer_name(const Params& params)
     if (addrlen_value <= 0)
         return EINVAL;
 
-    auto description = fds().file_description(params.sockfd);
-    if (!description)
-        return EBADF;
-
+    auto description = TRY(fds().file_description(params.sockfd));
     if (!description->is_socket())
         return ENOTSOCK;
 
@@ -330,13 +310,10 @@ KResultOr<FlatPtr> Process::sys$getsockopt(Userspace<const Syscall::SC_getsockop
     socklen_t value_size;
     TRY(copy_from_user(&value_size, params.value_size, sizeof(socklen_t)));
 
-    auto description = fds().file_description(sockfd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(sockfd));
     if (!description->is_socket())
         return ENOTSOCK;
     auto& socket = *description->socket();
-
     REQUIRE_PROMISE_FOR_SOCKET_DOMAIN(socket.domain());
     return socket.getsockopt(*description, level, option, user_value, user_value_size);
 }
@@ -347,9 +324,7 @@ KResultOr<FlatPtr> Process::sys$setsockopt(Userspace<const Syscall::SC_setsockop
     auto params = TRY(copy_typed_from_user(user_params));
 
     Userspace<const void*> user_value((FlatPtr)params.value);
-    auto description = fds().file_description(params.sockfd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(params.sockfd));
     if (!description->is_socket())
         return ENOTSOCK;
     auto& socket = *description->socket();
diff --git a/Kernel/Syscalls/stat.cpp b/Kernel/Syscalls/stat.cpp
index dc601d9f08..31d0cd9c6e 100644
--- a/Kernel/Syscalls/stat.cpp
+++ b/Kernel/Syscalls/stat.cpp
@@ -15,9 +15,7 @@ KResultOr<FlatPtr> Process::sys$fstat(int fd, Userspace<stat*> user_statbuf)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     REQUIRE_PROMISE(stdio);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     stat buffer = {};
     TRY(description->stat(buffer));
     return copy_to_user(user_statbuf, &buffer);
@@ -35,9 +33,7 @@ KResultOr<FlatPtr> Process::sys$stat(Userspace<const Syscall::SC_stat_params*> u
     if (params.dirfd == AT_FDCWD) {
         base = current_directory();
     } else {
-        auto base_description = fds().file_description(params.dirfd);
-        if (!base_description)
-            return EBADF;
+        auto base_description = TRY(fds().file_description(params.dirfd));
         if (!base_description->is_directory())
             return ENOTDIR;
         if (!base_description->custody())
diff --git a/Kernel/Syscalls/statvfs.cpp b/Kernel/Syscalls/statvfs.cpp
index e9a91bc502..a530266c86 100644
--- a/Kernel/Syscalls/statvfs.cpp
+++ b/Kernel/Syscalls/statvfs.cpp
@@ -76,10 +76,7 @@ KResultOr<FlatPtr> Process::sys$fstatvfs(int fd, statvfs* buf)
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     REQUIRE_PROMISE(stdio);
 
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
-
+    auto description = TRY(fds().file_description(fd));
     return do_statvfs(description->absolute_path(), buf);
 }
 
diff --git a/Kernel/Syscalls/ttyname.cpp b/Kernel/Syscalls/ttyname.cpp
index 5e795d9ff6..1b0cb09309 100644
--- a/Kernel/Syscalls/ttyname.cpp
+++ b/Kernel/Syscalls/ttyname.cpp
@@ -15,9 +15,7 @@ KResultOr<FlatPtr> Process::sys$ttyname(int fd, Userspace<char*> buffer, size_t
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     REQUIRE_PROMISE(tty);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     if (!description->is_tty())
         return ENOTTY;
     auto tty_name = description->tty()->tty_name();
@@ -30,9 +28,7 @@ KResultOr<FlatPtr> Process::sys$ptsname(int fd, Userspace<char*> buffer, size_t
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     REQUIRE_PROMISE(tty);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     auto* master_pty = description->master_pty();
     if (!master_pty)
         return ENOTTY;
diff --git a/Kernel/Syscalls/write.cpp b/Kernel/Syscalls/write.cpp
index 4329666d3c..aaec7dc66f 100644
--- a/Kernel/Syscalls/write.cpp
+++ b/Kernel/Syscalls/write.cpp
@@ -33,10 +33,7 @@ KResultOr<FlatPtr> Process::sys$writev(int fd, Userspace<const struct iovec*> io
             return EINVAL;
     }
 
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
-
+    auto description = TRY(fds().file_description(fd));
     if (!description->is_writable())
         return EBADF;
 
@@ -104,9 +101,7 @@ KResultOr<FlatPtr> Process::sys$write(int fd, Userspace<const u8*> data, size_t
         return EINVAL;
 
     dbgln_if(IO_DEBUG, "sys$write({}, {}, {})", fd, data.ptr(), size);
-    auto description = fds().file_description(fd);
-    if (!description)
-        return EBADF;
+    auto description = TRY(fds().file_description(fd));
     if (!description->is_writable())
         return EBADF;