feat: vfs - add stat syscall

kernel/src/Api/BuildNo.hpp

@@ -12,4 +12,4 @@
 
 #pragma once
 
-#define MONTAUK_BUILD_NUMBER 2
+#define MONTAUK_BUILD_NUMBER 4

kernel/src/Api/Filesystem.hpp

@@ -116,6 +116,23 @@ namespace montauk::abi {
         return Fs::Vfs::VfsDelete(resolved);
     }
 
+    static int Sys_Stat(const char* path, FileStat* out) {
+        if (out == nullptr) return -1;
+        char resolved[256];
+        if (!ResolveProcessPath(path, resolved, sizeof(resolved))) return -1;
+
+        Fs::Vfs::StatInfo info;
+        if (Fs::Vfs::VfsStat(resolved, info) != 0) return -1;
+
+        out->size  = info.size;
+        out->mtime = info.mtime;
+        out->ctime = info.ctime;
+        out->atime = info.atime;
+        out->mode  = info.mode;
+        out->isDir = info.isDir ? 1u : 0u;
+        return 0;
+    }
+
     static int Sys_FMkdir(const char* path) {
         char resolved[256];
         if (!ResolveProcessPath(path, resolved, sizeof(resolved))) return -1;

kernel/src/Api/Syscall.cpp

@@ -153,6 +153,10 @@ namespace montauk::abi {
             case SYS_GETEXECPATH:
                 if (!UserMemory::Range(frame->arg2 ? frame->arg1 : frame->arg1, frame->arg2, true)) return -1;
                 return Sys_GetExecPath((char*)frame->arg1, frame->arg2);
+            case SYS_STAT:
+                if (!UserMemory::String(frame->arg1, kMaxPathBytes)) return -1;
+                if (!UserMemory::Writable<FileStat>(frame->arg2)) return -1;
+                return (int64_t)Sys_Stat((const char*)frame->arg1, (FileStat*)frame->arg2);
             case SYS_TERMSIZE:
                 return (int64_t)Sys_TermSize();
             case SYS_GETARGS:

kernel/src/Api/Syscall.hpp

@@ -285,6 +285,9 @@ namespace montauk::abi {
     // Absolute path of the running executable (for argv[0]).
     static constexpr uint64_t SYS_GETEXECPATH         = 151;  // (index, flags) -> new front index; index=-1 queries support (1/0); flags bit0 = wait vsync
 
+    // Path metadata (size, timestamps, mode). (const char* path, FileStat* out) -> 0, -1 on error/unsupported.
+    static constexpr uint64_t SYS_STAT                = 152;
+
     // Tunable parameters (for SYS_SDR_SETPARAM / SYS_SDR_GETPARAM).
     static constexpr int SDR_PARAM_FREQ        = 0;  // center frequency, Hz
     static constexpr int SDR_PARAM_SAMPLE_RATE = 1;  // sample rate, Hz
@@ -326,6 +329,17 @@ namespace montauk::abi {
         uint8_t Second;
     };
 
+    // Path metadata returned by SYS_STAT. Timestamps are UTC unix seconds;
+    // a filesystem that does not record a given time reports it as 0.
+    struct FileStat {
+        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 mode bits (type + permissions)
+        uint32_t isDir;    // 1 if the entry is a directory, else 0
+    };
+
     struct FbInfo {
         uint64_t width;
         uint64_t height;