Add statx-based stat implementation for Linux

python · ntninja · Mar 22, 2020 · Mar 23, 2020 · Mar 23, 2020 · Mar 23, 2020
commit 54a23b5e1778ce427b0cec7bf190d11ebc7df75a
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
@@ -466,10 +466,17 @@ extern char        *ctermid_r(char *);
 #  define LSTAT win32_lstat
 #  define FSTAT _Py_fstat_noraise
 #  define STRUCT_STAT struct _Py_stat_struct
+#elif defined(HAVE_LINUX_STATX)
+#  define STAT linux_stat
+#  define LSTAT linux_lstat
+#  define FSTAT linux_fstat
+#  define FSTATAT linux_fstatat
+#  define STRUCT_STAT struct statx
 #else
 #  define STAT stat
 #  define LSTAT lstat
 #  define FSTAT fstat
+#  define FSTATAT fstatat
 #  define STRUCT_STAT struct stat
 #endif
 
@@ -2066,6 +2073,39 @@ win32_stat(const wchar_t* path, struct _Py_stat_struct *result)
 
 #endif /* MS_WINDOWS */
 
+
+#ifdef HAVE_LINUX_STATX
+
+// Extend this list when adding support for new Linux statx fields
+#define LINUX_STATX_MASK STATX_BASIC_STATS | STATX_BTIME
+
+static int
+linux_stat(const char* path, struct statx* result)
+{
+    return statx(AT_FDCWD, path, 0, LINUX_STATX_MASK, result);
+}
+
+static int
+linux_lstat(const char* path, struct statx* result)
+{
+    return statx(AT_FDCWD, path, AT_SYMLINK_NOFOLLOW, LINUX_STATX_MASK, result);
+}
+
+static int
+linux_fstat(int fd, struct statx* result)
+{
+    return statx(fd, "", AT_EMPTY_PATH, LINUX_STATX_MASK, result);
+}
+
+static int
+linux_fstatat(int dirfd, const char* path, struct statx* result, int flags)
+{
+    return statx(dirfd, path, flags, LINUX_STATX_MASK, result);
+}
+
+#endif /* HAVE_LINUX_STATX */
+
+
 PyDoc_STRVAR(stat_result__doc__,
 "stat_result: Result from stat, fstat, or lstat.\n\n\
 This object may be accessed either as a tuple of\n\
@@ -2121,6 +2161,10 @@ static PyStructSequence_Field stat_result_fields[] = {
 #endif
 #ifdef HAVE_STRUCT_STAT_ST_REPARSE_TAG
     {"st_reparse_tag", "Windows reparse tag"},
+#endif
+#ifdef HAVE_LINUX_STATX
+    {"st_attributes", "Linux file attribute bits"},
+    {"st_attributes_mask", "Linux supported file attribute bits on this filesystem"},
 #endif
     {0}
 };
@@ -2173,6 +2217,14 @@ static PyStructSequence_Field stat_result_fields[] = {
 #define ST_REPARSE_TAG_IDX ST_FSTYPE_IDX
 #endif
 
+#ifdef HAVE_LINUX_STATX
+#define ST_ATTRIBUTES_IDX (ST_REPARSE_TAG_IDX+1)
+#define ST_ATTRIBUTES_MASK_IDX (ST_REPARSE_TAG_IDX+2)
+#else
+#define ST_ATTRIBUTES_IDX ST_REPARSE_TAG_IDX
+#define ST_ATTRIBUTES_MASK_IDX ST_REPARSE_TAG_IDX
+#endif
+
 static PyStructSequence_Desc stat_result_desc = {
     "stat_result", /* name */
     stat_result__doc__, /* doc */
@@ -2357,6 +2409,78 @@ fill_time(PyObject *module, PyObject *v, int index1, int index2, int index3,
     Py_XDECREF(float_s);
 }
 
+#ifdef HAVE_LINUX_STATX
+
+/* pack a system statx C structure into the Python stat tuple
+   (used by posix_stat() and posix_fstat()) */
+static PyObject*
+_pystat_fromstructstat(PyObject *module, struct statx* stx)
+{
+    unsigned long long attributes;
+    PyObject *StatResultType = get_posix_state(module)->StatResultType;
+    PyObject *v = PyStructSequence_New((PyTypeObject *)StatResultType);
+    if (v == NULL)
+        return NULL;
+
+    if(stx->stx_mask & STATX_TYPE) {
+        PyStructSequence_SET_ITEM(v, 0, PyLong_FromLong((long)stx->stx_mode));
+    }
+    if(stx->stx_mask & STATX_INO) {
+        Py_BUILD_ASSERT(sizeof(unsigned long long) >= sizeof(stx->stx_ino));
+        PyStructSequence_SET_ITEM(v, 1, PyLong_FromUnsignedLongLong(stx->stx_ino));
+    }
+    PyStructSequence_SET_ITEM(v, 2, _PyLong_FromDev(makedev(stx->stx_dev_major, stx->stx_dev_minor)));
+    if(stx->stx_mask & STATX_NLINK) {
+        PyStructSequence_SET_ITEM(v, 3, PyLong_FromLong((long)stx->stx_nlink));
+    }
+    if(stx->stx_mask & STATX_UID) {
+        PyStructSequence_SET_ITEM(v, 4, _PyLong_FromUid(stx->stx_uid));
+    }
+    if(stx->stx_mask & STATX_GID) {
+        PyStructSequence_SET_ITEM(v, 5, _PyLong_FromGid(stx->stx_gid));
+    }
+    Py_BUILD_ASSERT(sizeof(long long) >= sizeof(stx->stx_size));
+    PyStructSequence_SET_ITEM(v, 6, PyLong_FromLongLong(stx->stx_size));
+
+    if(stx->stx_mask & STATX_ATIME) {
+        fill_time(module, v, 7, 10, 14, stx->stx_atime.tv_sec, stx->stx_atime.tv_nsec);
+    }
+    if(stx->stx_mask & STATX_MTIME) {
+        fill_time(module, v, 8, 11, 15, stx->stx_mtime.tv_sec, stx->stx_mtime.tv_nsec);
+    }
+    if(stx->stx_mask & STATX_CTIME) {
+        fill_time(module, v, 9, 12, 16, stx->stx_ctime.tv_sec, stx->stx_ctime.tv_nsec);
+    }
+    if(stx->stx_mask & STATX_BTIME) {
+        fill_time(module, v, -1, 13, 17, stx->stx_btime.tv_sec, stx->stx_btime.tv_nsec);
+    }
+
+    attributes = stx->stx_attributes & stx->stx_attributes_mask;
+    PyStructSequence_SET_ITEM(v, ST_ATTRIBUTES_IDX,
+                              PyLong_FromUnsignedLongLong(attributes));
+    PyStructSequence_SET_ITEM(v, ST_ATTRIBUTES_MASK_IDX,
+                              PyLong_FromUnsignedLongLong(stx->stx_attributes_mask));
+
+    PyStructSequence_SET_ITEM(v, ST_BLKSIZE_IDX,
+                              PyLong_FromLong((long)stx->stx_blksize));
+    if(stx->stx_mask & STATX_BLOCKS) {
+        PyStructSequence_SET_ITEM(v, ST_BLOCKS_IDX,
+                                  PyLong_FromLong((long)stx->stx_blocks));
+    }
+
+    PyStructSequence_SET_ITEM(v, ST_RDEV_IDX,
+                              _PyLong_FromDev(makedev(stx->stx_rdev_major, stx->stx_rdev_minor)));
+
+    if (PyErr_Occurred()) {
+        Py_DECREF(v);
+        return NULL;
+    }
+
+    return v;
+}
+
+#else /* HAVE_LINUX_STATX */
+
 /* pack a system stat C structure into the Python stat tuple
    (used by posix_stat() and posix_fstat()) */
 static PyObject*
@@ -2473,6 +2597,8 @@ _pystat_fromstructstat(PyObject *module, STRUCT_STAT *st)
     return v;
 }
 
+#endif /* !HAVE_LINUX_STATX */
+
 /* POSIX methods */
 
 
@@ -2515,7 +2641,7 @@ posix_do_stat(PyObject *module, const char *function_name, path_t *path,
 #ifdef HAVE_FSTATAT
     if ((dir_fd != DEFAULT_DIR_FD) || !follow_symlinks) {
         if (HAVE_FSTATAT_RUNTIME) {
-            result = fstatat(dir_fd, path->narrow, &st,
+            result = FSTATAT(dir_fd, path->narrow, &st,
                          follow_symlinks ? 0 : AT_SYMLINK_NOFOLLOW);
 
         } else {
@@ -13560,7 +13686,7 @@ DirEntry_fetch_stat(PyObject *module, DirEntry *self, int follow_symlinks)
 #ifdef HAVE_FSTATAT
       if (HAVE_FSTATAT_RUNTIME) {
         Py_BEGIN_ALLOW_THREADS
-        result = fstatat(self->dir_fd, path, &st,
+        result = FSTATAT(self->dir_fd, path, &st,
                          follow_symlinks ? 0 : AT_SYMLINK_NOFOLLOW);
         Py_END_ALLOW_THREADS
       } else