unix: Add "_os" module with stat().

stat() is bad function to use using FFI, because its ABI is largely private.
To start with, Glibc .so doesn't even have "stat" symbol. Then, layout of
struct stat is too implementation-dependent. So, introduce _os to deal
with stat() and other similar cases.

unix/Makefile

@@ -68,6 +68,7 @@ SRC_C = \
 	input.c \
 	file.c \
 	modsocket.c \
+	modos.c \
 	$(SRC_MOD)
 
 OBJ = $(PY_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))

unix/modos.c

+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013, 2014 Damien P. George
+ * Copyright (c) 2014 Paul Sokolovsky
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "misc.h"
+#include "mpconfig.h"
+#include "nlr.h"
+#include "qstr.h"
+#include "obj.h"
+#include "runtime.h"
+#include "objtuple.h"
+
+#define RAISE_ERRNO(err_flag, error_val) \
+    { if (err_flag == -1) \
+        { nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT((machine_int_t)error_val))); } }
+
+STATIC mp_obj_t mod_os_stat(mp_obj_t path_in) {
+    struct stat sb;
+    const char *path = mp_obj_str_get_str(path_in);
+
+    int res = stat(path, &sb);
+    RAISE_ERRNO(res, errno);
+
+    mp_obj_tuple_t *t = mp_obj_new_tuple(10, NULL);
+    t->items[0] = MP_OBJ_NEW_SMALL_INT(sb.st_mode);
+    t->items[1] = MP_OBJ_NEW_SMALL_INT(sb.st_ino);
+    t->items[2] = MP_OBJ_NEW_SMALL_INT((machine_int_t)sb.st_dev);
+    t->items[3] = MP_OBJ_NEW_SMALL_INT(sb.st_nlink);
+    t->items[4] = MP_OBJ_NEW_SMALL_INT(sb.st_uid);
+    t->items[5] = MP_OBJ_NEW_SMALL_INT(sb.st_gid);
+    t->items[6] = MP_OBJ_NEW_SMALL_INT(sb.st_size);
+    t->items[7] = MP_OBJ_NEW_SMALL_INT(sb.st_atime);
+    t->items[8] = MP_OBJ_NEW_SMALL_INT(sb.st_mtime);
+    t->items[9] = MP_OBJ_NEW_SMALL_INT(sb.st_ctime);
+    return t;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_os_stat_obj, mod_os_stat);
+
+STATIC const mp_map_elem_t mp_module_os_globals_table[] = {
+    { MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR__os) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_stat), (mp_obj_t)&mod_os_stat_obj },
+};
+
+STATIC const mp_obj_dict_t mp_module_os_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = ARRAY_SIZE(mp_module_os_globals_table),
+        .alloc = ARRAY_SIZE(mp_module_os_globals_table),
+        .table = (mp_map_elem_t*)mp_module_os_globals_table,
+    },
+};
+
+const mp_obj_module_t mp_module_os = {
+    .base = { &mp_type_module },
+    .name = MP_QSTR__os,
+    .globals = (mp_obj_dict_t*)&mp_module_os_globals,
+};

unix/mpconfigport.h

@@ -49,6 +49,7 @@
 // names in exception messages (may require more RAM).
 #define MICROPY_ERROR_REPORTING     (MICROPY_ERROR_REPORTING_DETAILED)
 
+extern const struct _mp_obj_module_t mp_module_os;
 extern const struct _mp_obj_module_t mp_module_time;
 extern const struct _mp_obj_module_t mp_module_socket;
 extern const struct _mp_obj_module_t mp_module_ffi;
@@ -68,6 +69,7 @@ extern const struct _mp_obj_module_t mp_module_ffi;
     MICROPY_MOD_FFI_DEF \
     MICROPY_MOD_TIME_DEF \
     { MP_OBJ_NEW_QSTR(MP_QSTR_microsocket), (mp_obj_t)&mp_module_socket }, \
+    { MP_OBJ_NEW_QSTR(MP_QSTR__os), (mp_obj_t)&mp_module_os }, \
 
 // type definitions for the specific machine
 

unix/qstrdefsport.h

@@ -33,6 +33,9 @@ Q(makefile)
 
 Q(FileIO)
 
+Q(_os)
+Q(stat)
+
 Q(ffi)
 Q(ffimod)
 Q(ffifunc)