fix(libkernel): report a 64 KiB st_blksize for directories

core/libs/prx/libkernel/File/src/ArchivedFile.cpp

@@ -35,6 +35,7 @@ void FillNode(const AppArchiveNode& node, FileStat* sb) {
     sb->st_nlink = node.Directory ? 2 : 1;
     sb->st_size = static_cast<std::int64_t>(node.Size);
     sb->st_blocks = static_cast<std::int64_t>((node.Size + 511) / 512);
+    if (node.Directory) sb->st_blksize = 0x10000;
 }
 
 }

core/libs/prx/libkernel/File/src/NativeStat.cpp

@@ -169,6 +169,7 @@ static void CopyNativeStat(const NativeStat& st, FileStat* sb) {
     sb->st_birthtim.tv_nsec = static_cast<std::int64_t>(st.st_birthtim.tv_nsec);
 #endif
 #endif
+    if ((sb->st_mode & 0170000) == 0040000) sb->st_blksize = 0x10000;
 }
 
 namespace File {

core/libs/tests/GuestFilesystem.cpp

@@ -9,6 +9,9 @@
 #include "prx/libkernel/File/include/NativeStat.hpp"
 #include "prx/libkernel/KernelErrors.hpp"
 #include "tests/TemporaryFile.hpp"
+#ifndef _WIN32
+#include <sys/stat.h>
+#endif
 #include <algorithm>
 #include <array>
 #include <chrono>
@@ -1434,7 +1437,18 @@ int main() {
     Require(close_nid_postfix(plainFile) == 0);
     Require(close_nid_postfix(directoryDescriptor) == 0);
     const int flaggedDirectory = sceKernelOpen(rootName.c_str(), 0x20000, 0);
-    Require(flaggedDirectory >= 0 && sceKernelClose(flaggedDirectory) == 0);
+    FileStat directoryStatus{};
+    Require(flaggedDirectory >= 0 && sceKernelFstat(flaggedDirectory, &directoryStatus) == 0 && directoryStatus.st_blksize == 0x10000);
+    Require(sceKernelStat(rootName.c_str(), &directoryStatus) == 0 && directoryStatus.st_blksize == 0x10000);
+    FileStat fileStatus{};
+#ifdef _WIN32
+    Require(sceKernelStat(presentName.c_str(), &fileStatus) == 0 && fileStatus.st_blksize == 512);
+#else
+    struct stat presentHostStat {};
+    Require(::stat(presentName.c_str(), &presentHostStat) == 0);
+    Require(sceKernelStat(presentName.c_str(), &fileStatus) == 0 && fileStatus.st_blksize == static_cast<decltype(fileStatus.st_blksize)>(presentHostStat.st_blksize));
+#endif
+    Require(sceKernelClose(flaggedDirectory) == 0);
     std::vector<char> entries(4096);
     for (const auto& directoryName : {std::string("/"), std::string("."), rootName + "/", rootName + "/.."}) {
         const int listed = sceKernelOpen(directoryName.c_str(), 0x20000, 0);

core/libs/tests/GuestKernelAppArchive.cpp

@@ -387,7 +387,7 @@ void Status() {
     FileStat status{};
     Check(sceKernelStat("/app0/Data/Small.txt", &status) == 0);
     Check((status.st_mode & TypeMask) == RegularType && (status.st_mode & 0222) == 0 && status.st_size == 3 && status.st_blocks == 1);
-    Check(sceKernelStat("/app0/data", &status) == 0 && (status.st_mode & TypeMask) == DirectoryType);
+    Check(sceKernelStat("/app0/data", &status) == 0 && (status.st_mode & TypeMask) == DirectoryType && status.st_blksize == 0x10000);
     Check(sceKernelStat("/app0/Data/", &status) == 0);
     Check(sceKernelStat("/app0/Data/Small.txt/", &status) == SCE_KERNEL_ERROR_ENOTDIR);
     Check(sceKernelStat("/app0/Data/Missing.txt", &status) == SCE_KERNEL_ERROR_ENOENT);

docs/dev/debt/libkernel.md

@@ -173,6 +173,7 @@
 - [Windows file timestamps](../../../core/libs/prx/libkernel/File/include/WindowsFileTime.hpp) use the host filesystem's timestamp range and resolution. `utimes`, `futimes`, and `lutimes` reject timestamps outside nonnegative signed 64-bit Windows file-time ticks with `EINVAL`, including exactly 1601-01-01 00:00:00 UTC, whose zero value means "leave unchanged" to `SetFileTime`. Directory timestamp updates resolve the current path of the opened handle. Filesystems with coarser timestamp resolution cannot retain every guest microsecond. Birth-time clamping is not atomic with concurrent host timestamp updates and has not been measured on a console
 - [EVFILT_VNODE on macOS](../../../core/libs/prx/libkernel/Equeue/src/FileEvent.cpp) (libkernel) registers `EVFILT_VNODE` on a duplicate of the descriptor in a host kqueue, whose notes have FreeBSD's values, and drops the `NOTE_LINK` that XNU adds to `NOTE_DELETE` when the watched file or directory is removed, since FreeBSD's `vop_remove_post` and `vop_rmdir_post` report `NOTE_DELETE` alone. As on Windows, a directory registered with `NOTE_EXTEND` is accepted but never receives it: XNU reports a move between directories as `NOTE_WRITE` alone, with `NOTE_LINK` for a subdirectory
 - [Windows file identity](../../../core/libs/prx/libkernel/File/src/NativeStat.cpp) (libkernel) - `stat` and `fstat` report the volume serial number as `st_dev` and the 64-bit file index folded into the guest's 32-bit `st_ino` (never 0), so two different files can in principle share an `st_ino`; the fold is not taken from a reference. `st_nlink` is clamped to 65535, the width of the guest field. The call keeps the `_wstat64` values when `GetFileInformationByHandle` fails
+- [Directory st_blksize](../../../core/libs/prx/libkernel/File/src/NativeStat.cpp) (libkernel) - `stat` and `fstat` report `st_blksize` 0x10000 for every directory, app0.zar directories included, as a PS4 Pro (firmware 10.71) reports for `/app0`, `/app0/sce_sys` and the system library directory. Titles size one `getdents` buffer from it: CUSA18659 reads `st_blksize` + 264 bytes once. The console reports 0x8000 for `/data` directories, which are not told apart here, and files keep the host's value (512 on Windows) where `/app0` files report 0x10000
 - [lstat of a Windows symbolic link](../../../core/libs/prx/libkernel/File/src/NativeStat.cpp) (libkernel) reports a link whose target is relative, as `symlink` creates them, with the link's own times, `st_dev` and `st_ino`, mode `S_IFLNK | 0777` and the length of the target `readlink` returns as `st_size`. FreeBSD gives a new link `0777` less the creating process's umask, which the host does not keep, so the permission bits are not the console's. A link with an absolute target is reported the same way, using its print name, or its substitute name when the print name is empty, without a `\??\` or `\\?\` prefix. A directory junction is treated as a link only when `ReadJunction` in [WindowsSymbolicLink.hpp](../../../core/libs/prx/libkernel/File/include/WindowsSymbolicLink.hpp) accepts a drive-path target (`X:\...`) after stripping `\??\` / `\\?\`; volume mounts and other non-drive substitutes are not. Consumers of that drive-target path: [NativeStat.cpp](../../../core/libs/prx/libkernel/File/src/NativeStat.cpp) (`lstat`/`readlink`), [Open.cpp](../../../core/libs/prx/libkernel/File/src/Open.cpp) (`O_NOFOLLOW` → `EMLINK`, and `unlink` removing the junction), [Stdio.cpp](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (`rmdir` → `ENOTDIR`), and [Export.cpp](../../../core/libs/prx/libkernel_sys/Export.cpp) (`unlinkat` with and without `AT_REMOVEDIR`). `unlink` / plain `unlinkat` leave the target, including when it is not empty
 - [lstat of a Windows reparse point that is not a link](../../../core/libs/prx/libkernel/File/src/NativeStat.cpp) (libkernel) reports a mounted volume (`\??\Volume{GUID}\`) or another name surrogate as the reparse point itself, not followed, with the mode of its attributes, as CPython's `os.lstat` does, and a reparse point without the name surrogate bit (deduplication, cloud files) as `stat` reports it
 - [sceKernelMapDirectMemory with execute](../../../core/libs/prx/libkernel/DirectMemory/DirectMemory.cpp) (libkernel) - a protection with CPU execute (bit 0x4) returns `EINVAL` (0x80020016) and maps nothing, and `sceKernelMprotect` grants execute afterwards, as [PS5_PayloadSDK measured](https://github.com/mihawk-99/PS5_PayloadSDK/blob/3e31e0b1b68ada28beca68adc480cf0c3d17b9df/platform/docs/PROBE.md#L28-L34) in a title on firmware 12.09 for read-execute and read-write-execute. `sceKernelMapDirectMemory2`, `sceKernelMapNamedDirectMemory`, and `sceKernelBatchMap` and `sceKernelBatchMap2` with operation 0 share the check here, which is not measured for them, nor for a title with more privileges than a homebrew one. Of 40 `sceKernelMapDirectMemory` calls in ten titles checked, 35 pass a constant protection without execute and five read it from a register or field (one each in PPSA01494, PPSA21564 and PPSA30839, two in PPSA18194).