kapi: implement seek support

2 files changed, 27 insertions, 0 deletions

diff --git a/kernel/kapi/filesystem.cpp b/kernel/kapi/filesystem.cpp
index 5280b4fa..d37a4cf7 100644
--- a/kernel/kapi/filesystem.cpp
+++ b/kernel/kapi/filesystem.cpp
@@ -57,6 +57,14 @@ namespace kapi::filesystem
     });
   }
 
+  auto seek(size_t file_descriptor, kstd::units::bytes offset, seek_direction direction, seek_origin origin)
+      -> kstd::result<kstd::units::bytes>
+  {
+    return kernel::filesystem::open_file_table::get().file(file_descriptor).and_then([=](auto file) {
+      return file->seek(offset, direction, origin);
+    });
+  }
+
   auto mkdir(std::string_view path) -> kstd::result<void>
   {
     return kernel::filesystem::vfs::get().mkdir(path);
diff --git a/kernel/kapi/filesystem.tests.cpp b/kernel/kapi/filesystem.tests.cpp
index 80fc7d3f..2f975bf8 100644
--- a/kernel/kapi/filesystem.tests.cpp
+++ b/kernel/kapi/filesystem.tests.cpp
@@ -3,6 +3,7 @@
 #include <kernel/test_support/filesystem/storage_boot_module_vfs_fixture.hpp>
 
 #include <kstd/system_error.hpp>
+#include <kstd/units.hpp>
 
 #include <catch2/catch_test_macros.hpp>
 
@@ -142,6 +143,24 @@ SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_vfs_fixture, "Kap
       REQUIRE(kapi::filesystem::umount("/information"));
     }
 
+    AND_GIVEN("an open file")
+    {
+      auto file = kapi::filesystem::open("/closed.txt");
+      REQUIRE(file);
+
+      THEN("seeking forward from the beginning succeeds")
+      {
+        REQUIRE(kapi::filesystem::seek(*file, 100_B, kapi::filesystem::seek_direction::forward,
+                                       kapi::filesystem::seek_origin::beginning) == 100_B);
+      }
+
+      THEN("seeking backward from the beginning fails")
+      {
+        REQUIRE_FALSE(kapi::filesystem::seek(*file, 100_B, kapi::filesystem::seek_direction::backward,
+                                             kapi::filesystem::seek_origin::beginning));
+      }
+    }
+
     THEN("device can be opened as file and read from")
     {
       auto fd = kapi::filesystem::open("/dev/ram0").value();