feat: vfs - add stat syscall

kernel/src/Fs/Ext2.cpp

@@ -1189,6 +1189,24 @@ namespace Fs::Ext2 {
         return -1;
     }
 
+    static int StatImpl(int inst, const char* path, Vfs::StatInfo* out) {
+        if (!out) return -1;
+        if (inst < 0 || inst >= g_instanceCount || !g_instances[inst].active) return -1;
+        auto& self = g_instances[inst];
+
+        uint32_t inodeNum;
+        Inode inode;
+        if (!TraversePath(self, path, &inodeNum, &inode)) return -1;
+
+        out->size  = inode.i_size;
+        out->mtime = (int64_t)inode.i_mtime;
+        out->ctime = (int64_t)inode.i_ctime;
+        out->atime = (int64_t)inode.i_atime;
+        out->mode  = inode.i_mode;
+        out->isDir = (inode.i_mode & IMODE_TYPE_MASK) == IMODE_DIR;
+        return 0;
+    }
+
     static int ReadImpl(int inst, int handle, uint8_t* buffer,
                          uint64_t offset, uint64_t size) {
         if (inst < 0 || inst >= g_instanceCount) return -1;
@@ -1764,6 +1782,7 @@ namespace Fs::Ext2 {
         static int Mkdir(const char* p) { return MkdirImpl(N, p); }
         static int Rename(const char* o, const char* n) { return RenameImpl(N, o, n); }
         static const char* GetLabel() { return GetLabelImpl(N); }
+        static int Stat(const char* p, Vfs::StatInfo* o) { return StatImpl(N, p, o); }
     };
 
     template<int N>
@@ -1781,6 +1800,7 @@ namespace Fs::Ext2 {
             Thunks<N>::Rename,
             Thunks<N>::GetLabel,
             Thunks<N>::ReadDirAt,
+            Thunks<N>::Stat,
         };
     }
 

kernel/src/Fs/Vfs.cpp

@@ -288,6 +288,25 @@ namespace Fs::Vfs {
         return result;
     }
 
+    int VfsStat(const char* path, StatInfo& out) {
+        int drive;
+        const char* localPath;
+
+        out = StatInfo{};
+
+        if (!ParsePath(path, drive, localPath)) return -1;
+        if (drive < 0 || drive >= MaxDrives || !driveActive[drive] || driveTable[drive] == nullptr) return -1;
+        if (driveTable[drive]->Stat == nullptr) return -1;
+
+        vfsLock.Acquire();
+        FsDriver* driver = driveTable[drive];
+        int result = (driveActive[drive] && driver && driver->Stat)
+            ? driver->Stat(localPath, &out)
+            : -1;
+        vfsLock.Release();
+        return result;
+    }
+
     int VfsMkdir(const char* path) {
         int drive;
         const char* localPath;

kernel/src/Fs/Vfs.hpp

@@ -18,6 +18,17 @@ namespace Fs::Vfs {
         uint32_t generation;
     };
 
+    // Metadata for a single path, filled by FsDriver::Stat. Timestamps are UTC
+    // unix seconds; a filesystem that does not record a given time leaves it 0.
+    struct StatInfo {
+        uint64_t size;    // file size in bytes
+        int64_t  mtime;   // last data modification time
+        int64_t  ctime;   // last inode (metadata) change time
+        int64_t  atime;   // last access time
+        uint32_t mode;    // ext2/POSIX i_mode bits (type + permissions)
+        bool     isDir;   // true if the entry is a directory
+    };
+
     struct FsDriver {
         int (*Open)(const char* path);
         int (*Read)(int handle, uint8_t* buffer, uint64_t offset, uint64_t size);
@@ -33,6 +44,9 @@ namespace Fs::Vfs {
         // Optional: paginated directory read returning entries [startIndex, startIndex+maxEntries).
         // Drivers that leave this null are read via ReadDir at startIndex 0 only.
         int (*ReadDirAt)(const char* path, const char** outNames, int maxEntries, int startIndex);
+        // Optional: fill metadata for a path. Drivers that leave this null do
+        // not support stat and VfsStat returns -1 for their paths.
+        int (*Stat)(const char* path, StatInfo* out);
     };
 
     void Initialize();
@@ -51,6 +65,7 @@ namespace Fs::Vfs {
     void CloseBackendFile(BackendFile& file);
 
     int VfsDelete(const char* path);
+    int VfsStat(const char* path, StatInfo& out);
     int VfsReadDir(const char* path, const char** outNames, int maxEntries);
     int VfsReadDirAt(const char* path, const char** outNames, int maxEntries, int startIndex);
     int VfsMkdir(const char* path);