Implement file seek

Core/Memory/MemoryManager.cpp

@@ -46,10 +46,45 @@ namespace Memory
         return Size;
     }
 
+    SeekFSFunction(MEM_Seek)
+    {
+        long NewOffset;
+
+        if (Whence == SEEK_SET)
+        {
+            if (Offset > node->Length)
+                return -1;
+            node->Offset = Offset;
+            NewOffset = node->Offset;
+        }
+        else if (Whence == SEEK_CUR)
+        {
+            NewOffset = node->Offset + Offset;
+            if (NewOffset > node->Length || NewOffset < 0)
+                return -1;
+            node->Offset = NewOffset;
+        }
+        else if (Whence == SEEK_END)
+        {
+            NewOffset = node->Length + Offset;
+            if (NewOffset < 0)
+                return -1;
+            node->Offset = NewOffset;
+        }
+        else
+        {
+            error("Invalid whence!");
+            return -1;
+        }
+
+        return NewOffset;
+    }
+
     VirtualFileSystem::FileSystemOperations mem_op = {
         .Name = "mem",
         .Read = MEM_Read,
         .Write = MEM_Write,
+        .Seek = MEM_Seek,
     };
 
     uint64_t MemMgr::GetAllocatedMemorySize()

FileSystem/FS/ustar.cpp

@@ -36,9 +36,44 @@ namespace VirtualFileSystem
         return Size;
     }
 
+    SeekFSFunction(USTAR_Seek)
+    {
+        long NewOffset;
+
+        if (Whence == SEEK_SET)
+        {
+            if (Offset > node->Length)
+                return -1;
+            node->Offset = Offset;
+            NewOffset = node->Offset;
+        }
+        else if (Whence == SEEK_CUR)
+        {
+            NewOffset = node->Offset + Offset;
+            if (NewOffset > node->Length || NewOffset < 0)
+                return -1;
+            node->Offset = NewOffset;
+        }
+        else if (Whence == SEEK_END)
+        {
+            NewOffset = node->Length + Offset;
+            if (NewOffset < 0)
+                return -1;
+            node->Offset = NewOffset;
+        }
+        else
+        {
+            error("Invalid whence!");
+            return -1;
+        }
+
+        return NewOffset;
+    }
+
     FileSystemOperations ustar_op = {
         .Name = "ustar",
         .Read = USTAR_Read,
+        .Seek = USTAR_Seek,
     };
 
     USTAR::USTAR(uintptr_t Address, Virtual *vfs_ctx)

SystemCalls/Native.cpp

@@ -19,6 +19,7 @@
 #include <memory.hpp>
 #include <lock.hpp>
 #include <exec.hpp>
+#include <errno.h>
 
 #include <debug.h>
 
@@ -301,10 +302,19 @@ static uint64_t sys_file_write(SyscallsFrame *Frame, void *KernelPrivate, uint64
     UNUSED(Frame);
 }
 
-static int sys_file_seek(SyscallsFrame *Frame)
+static uint64_t sys_file_seek(SyscallsFrame *Frame, void *KernelPrivate, uint64_t Offset, int Whence)
 {
-    fixme("sys_file_seek: %#lx", Frame);
+    if (KernelPrivate == nullptr)
-    return SYSCALL_NOT_IMPLEMENTED;
+        return 0;
+
+    debug("(KernelPrivate: %#lx, Offset: %#lx, Whence: %#lx)", KernelPrivate, Offset, Whence);
+    VirtualFileSystem::File *KPObj = (VirtualFileSystem::File *)KernelPrivate;
+
+    if (KPObj->node->Operator->Seek == nullptr)
+        return SYSCALL_INTERNAL_ERROR;
+
+    return KPObj->node->Operator->Seek(KPObj->node, Offset, Whence);
+    UNUSED(Frame);
 }
 
 static int sys_file_status(SyscallsFrame *Frame)

include/filesystem.hpp

@@ -26,6 +26,10 @@ namespace VirtualFileSystem
 {
 #define FILENAME_LENGTH 256
 
+#define SEEK_SET 0
+#define SEEK_CUR 1
+#define SEEK_END 2
+
     struct Node;
 
     typedef size_t (*OperationMount)(const char *, unsigned long, const void *);
@@ -37,6 +41,7 @@ namespace VirtualFileSystem
     typedef size_t (*OperationSync)(void);
     typedef void (*OperationCreate)(Node *node, char *Name, uint16_t NameLength);
     typedef void (*OperationMkdir)(Node *node, char *Name, uint16_t NameLength);
+    typedef size_t (*OperationSeek)(Node *node, size_t Offset, uint8_t Whence);
 
 #define MountFSFunction(name) size_t name(const char *unknown0, unsigned long unknown1, const uint8_t *unknown2)
 #define UMountFSFunction(name) size_t name(int unknown0)
@@ -48,6 +53,7 @@ namespace VirtualFileSystem
 #define SyncFSFunction(name) size_t name(void)
 #define CreateFSFunction(name) void name(VirtualFileSystem::Node *node, char *Name, uint16_t NameLength)
 #define MkdirFSFunction(name) void name(VirtualFileSystem::Node *node, char *Name, uint16_t NameLength)
+#define SeekFSFunction(name) size_t name(VirtualFileSystem::Node *node, size_t Offset, uint8_t Whence)
 
     enum FileStatus
     {
@@ -101,6 +107,7 @@ namespace VirtualFileSystem
         OperationClose Close = nullptr;
         OperationCreate Create = nullptr;
         OperationMkdir MakeDirectory = nullptr;
+        OperationSeek Seek = nullptr;
     };
 
     struct Node
@@ -113,6 +120,7 @@ namespace VirtualFileSystem
         uint64_t UserIdentifier = 0, GroupIdentifier = 0;
         uintptr_t Address = 0;
         size_t Length = 0;
+        uint64_t Offset = 0;
         Node *Parent = nullptr;
         FileSystemOperations *Operator = nullptr;
         /* For root node:

syscalls.h

@@ -109,7 +109,7 @@ enum NativeSyscalls
     _FileWrite,
 
     /** @brief Seek in a file
-     * @fn
+     * @fn uint64_t FileSeek(void *KernelPrivate, uint64_t Offset, int Whence)
      * This syscall is used to change the current offset in a file.
      */
     _FileSeek,