Merge tag 'v1.9.1'2.0.0-alpha.0

Fixes for stmhal USB mass storage, lwIP bindings and VFS regressions

This release provides an important fix for the USB mass storage device in
the stmhal port by implementing the SCSI SYNCHRONIZE_CACHE command, which
is now require by some Operating Systems.  There are also fixes for the
lwIP bindings to improve non-blocking sockets and error codes.  The VFS has
some regressions fixed including the ability to statvfs the root.

All changes are listed below.

py core:
- modbuiltins: add core-provided version of input() function
- objstr: catch case of negative "maxsplit" arg to str.rsplit()
- persistentcode: allow to compile with complex numbers disabled
- objstr: allow to compile with obj-repr D, and unicode disabled
- modsys: allow to compile with obj-repr D and PY_ATTRTUPLE disabled
- provide mp_decode_uint_skip() to help reduce stack usage
- makeqstrdefs.py: make script run correctly with Python 2.6
- objstringio: if created from immutable object, follow copy on write policy

extmod:
- modlwip: connect: for non-blocking mode, return EINPROGRESS
- modlwip: fix error codes for duplicate calls to connect()
- modlwip: accept: fix error code for non-blocking mode
- vfs: allow to statvfs the root directory
- vfs: allow "buffering" and "encoding" args to VFS's open()
- modframebuf: fix signed/unsigned comparison pendantic warning

lib:
- libm: use isfinite instead of finitef, for C99 compatibility
- utils/interrupt_char: remove support for KBD_EXCEPTION disabled

tests:
- basics/string_rsplit: add tests for negative "maxsplit" argument
- float: convert "sys.exit()" to "raise SystemExit"
- float/builtin_float_minmax: PEP8 fixes
- basics: convert "sys.exit()" to "raise SystemExit"
- convert remaining "sys.exit()" to "raise SystemExit"

unix port:
- convert to use core-provided version of built-in import()
- Makefile: replace references to make with $(MAKE)

windows port:
- convert to use core-provided version of built-in import()

qemu-arm port:
- Makefile: adjust object-file lists to get correct dependencies
- enable micropython.mem_*() functions to allow more tests

stmhal port:
- boards: enable DAC for NUCLEO_F767ZI board
- add support for NUCLEO_F446RE board
- pass USB handler as parameter to allow more than one USB handler
- usb: use local USB handler variable in Start-of-Frame handler
- usb: make state for USB device private to top-level USB driver
- usbdev: for MSC implement SCSI SYNCHRONIZE_CACHE command
- convert from using stmhal's input() to core provided version

cc3200 port:
- convert from using stmhal's input() to core provided version

teensy port:
- convert from using stmhal's input() to core provided version

esp8266 port:
- Makefile: replace references to make with $(MAKE)
- Makefile: add clean-modules target
- convert from using stmhal's input() to core provided version

zephyr port:
- modusocket: getaddrinfo: Fix mp_obj_len() usage
- define MICROPY_PY_SYS_PLATFORM (to "zephyr")
- machine_pin: use native Zephyr types for Zephyr API calls

docs:
- machine.Pin: remove out_value() method
- machine.Pin: add on() and off() methods
- esp8266: consistently replace Pin.high/low methods with .on/off
- esp8266/quickref: polish Pin.on()/off() examples
- network: move confusingly-named cc3200 Server class to its reference
- uos: deconditionalize, remove minor port-specific details
- uos: move cc3200 port legacy VFS mounting functions to its ref doc
- machine: sort machine classes in logical order, not alphabetically
- network: first step to describe standard network class interface

examples:
- embedding: use core-provided KeyboardInterrupt object

1 files changed, 457 insertions, 0 deletions

diff --git a/extmod/vfs.c b/extmod/vfs.c
new file mode 100644
index 000000000..3bdce80db
--- /dev/null
+++ b/extmod/vfs.c
@@ -0,0 +1,457 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Damien P. George
+ *
+ * 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 <stdint.h>
+#include <string.h>
+
+#include "py/runtime0.h"
+#include "py/runtime.h"
+#include "py/objstr.h"
+#include "py/mperrno.h"
+#include "extmod/vfs.h"
+
+#if MICROPY_VFS
+
+#if MICROPY_VFS_FAT
+#include "extmod/vfs_fat.h"
+#endif
+
+// path is the path to lookup and *path_out holds the path within the VFS
+// object (starts with / if an absolute path).
+// Returns MP_VFS_ROOT for root dir (and then path_out is undefined) and
+// MP_VFS_NONE for path not found.
+mp_vfs_mount_t *mp_vfs_lookup_path(const char *path, const char **path_out) {
+    if (*path == '/' || MP_STATE_VM(vfs_cur) == MP_VFS_ROOT) {
+        // an absolute path, or the current volume is root, so search root dir
+        bool is_abs = 0;
+        if (*path == '/') {
+            ++path;
+            is_abs = 1;
+        }
+        if (*path == '\0') {
+            // path is "" or "/" so return virtual root
+            return MP_VFS_ROOT;
+        }
+        for (mp_vfs_mount_t *vfs = MP_STATE_VM(vfs_mount_table); vfs != NULL; vfs = vfs->next) {
+            size_t len = vfs->len - 1;
+            if (len == 0) {
+                *path_out = path - is_abs;
+                return vfs;
+            }
+            if (strncmp(path, vfs->str + 1, len) == 0) {
+                if (path[len] == '/') {
+                    *path_out = path + len;
+                    return vfs;
+                } else if (path[len] == '\0') {
+                    *path_out = "/";
+                    return vfs;
+                }
+            }
+        }
+
+        // if we get here then there's nothing mounted on /
+
+        if (is_abs) {
+            // path began with / and was not found
+            return MP_VFS_NONE;
+        }
+    }
+
+    // a relative path within a mounted device
+    *path_out = path;
+    return MP_STATE_VM(vfs_cur);
+}
+
+// Version of mp_vfs_lookup_path that takes and returns uPy string objects.
+STATIC mp_vfs_mount_t *lookup_path(mp_obj_t path_in, mp_obj_t *path_out) {
+    const char *path = mp_obj_str_get_str(path_in);
+    const char *p_out;
+    mp_vfs_mount_t *vfs = mp_vfs_lookup_path(path, &p_out);
+    if (vfs != MP_VFS_NONE && vfs != MP_VFS_ROOT) {
+        *path_out = mp_obj_new_str_of_type(mp_obj_get_type(path_in),
+            (const byte*)p_out, strlen(p_out));
+    }
+    return vfs;
+}
+
+STATIC mp_obj_t mp_vfs_proxy_call(mp_vfs_mount_t *vfs, qstr meth_name, size_t n_args, const mp_obj_t *args) {
+    if (vfs == MP_VFS_NONE) {
+        // mount point not found
+        mp_raise_OSError(MP_ENODEV);
+    }
+    if (vfs == MP_VFS_ROOT) {
+        // can't do operation on root dir
+        mp_raise_OSError(MP_EPERM);
+    }
+    mp_obj_t meth[n_args + 2];
+    mp_load_method(vfs->obj, meth_name, meth);
+    if (args != NULL) {
+        memcpy(meth + 2, args, n_args * sizeof(*args));
+    }
+    return mp_call_method_n_kw(n_args, 0, meth);
+}
+
+mp_import_stat_t mp_vfs_import_stat(const char *path) {
+    const char *path_out;
+    mp_vfs_mount_t *vfs = mp_vfs_lookup_path(path, &path_out);
+    if (vfs == MP_VFS_NONE || vfs == MP_VFS_ROOT) {
+        return MP_IMPORT_STAT_NO_EXIST;
+    }
+    #if MICROPY_VFS_FAT
+    // fast paths for known VFS types
+    if (mp_obj_get_type(vfs->obj) == &mp_fat_vfs_type) {
+        return fat_vfs_import_stat(MP_OBJ_TO_PTR(vfs->obj), path_out);
+    }
+    #endif
+    // TODO delegate to vfs.stat() method
+    return MP_IMPORT_STAT_NO_EXIST;
+}
+
+mp_obj_t mp_vfs_mount(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_readonly, ARG_mkfs };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_readonly, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_false} },
+        { MP_QSTR_mkfs, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_false} },
+    };
+
+    // parse args
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args - 2, pos_args + 2, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    // get the mount point
+    size_t mnt_len;
+    const char *mnt_str = mp_obj_str_get_data(pos_args[1], &mnt_len);
+
+    // see if we need to auto-detect and create the filesystem
+    mp_obj_t vfs_obj = pos_args[0];
+    mp_obj_t dest[2];
+    mp_load_method_maybe(vfs_obj, MP_QSTR_mount, dest);
+    if (dest[0] == MP_OBJ_NULL) {
+        // Input object has no mount method, assume it's a block device and try to
+        // auto-detect the filesystem and create the corresponding VFS entity.
+        // (At the moment we only support FAT filesystems.)
+        #if MICROPY_VFS_FAT
+        vfs_obj = mp_fat_vfs_type.make_new(&mp_fat_vfs_type, 1, 0, &vfs_obj);
+        #endif
+    }
+
+    // create new object
+    mp_vfs_mount_t *vfs = m_new_obj(mp_vfs_mount_t);
+    vfs->str = mnt_str;
+    vfs->len = mnt_len;
+    vfs->obj = vfs_obj;
+    vfs->next = NULL;
+
+    // call the underlying object to do any mounting operation
+    mp_vfs_proxy_call(vfs, MP_QSTR_mount, 2, (mp_obj_t*)&args);
+
+    // check that the destination mount point is unused
+    const char *path_out;
+    mp_vfs_mount_t *existing_mount = mp_vfs_lookup_path(mp_obj_str_get_str(pos_args[1]), &path_out);
+    if (existing_mount != MP_VFS_NONE && existing_mount != MP_VFS_ROOT) {
+        if (vfs->len != 1 && existing_mount->len == 1) {
+            // if root dir is mounted, still allow to mount something within a subdir of root
+        } else {
+            // mount point in use
+            mp_raise_OSError(MP_EPERM);
+        }
+    }
+
+    // insert the vfs into the mount table
+    mp_vfs_mount_t **vfsp = &MP_STATE_VM(vfs_mount_table);
+    while (*vfsp != NULL) {
+        if ((*vfsp)->len == 1) {
+            // make sure anything mounted at the root stays at the end of the list
+            vfs->next = *vfsp;
+            break;
+        }
+        vfsp = &(*vfsp)->next;
+    }
+    *vfsp = vfs;
+
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_KW(mp_vfs_mount_obj, 2, mp_vfs_mount);
+
+mp_obj_t mp_vfs_umount(mp_obj_t mnt_in) {
+    // remove vfs from the mount table
+    mp_vfs_mount_t *vfs = NULL;
+    size_t mnt_len;
+    const char *mnt_str = NULL;
+    if (MP_OBJ_IS_STR(mnt_in)) {
+        mnt_str = mp_obj_str_get_data(mnt_in, &mnt_len);
+    }
+    for (mp_vfs_mount_t **vfsp = &MP_STATE_VM(vfs_mount_table); *vfsp != NULL; vfsp = &(*vfsp)->next) {
+        if ((mnt_str != NULL && !memcmp(mnt_str, (*vfsp)->str, mnt_len + 1)) || (*vfsp)->obj == mnt_in) {
+            vfs = *vfsp;
+            *vfsp = (*vfsp)->next;
+            break;
+        }
+    }
+
+    if (vfs == NULL) {
+        mp_raise_OSError(MP_EINVAL);
+    }
+
+    // if we unmounted the current device then set current to root
+    if (MP_STATE_VM(vfs_cur) == vfs) {
+        MP_STATE_VM(vfs_cur) = MP_VFS_ROOT;
+    }
+
+    // call the underlying object to do any unmounting operation
+    mp_vfs_proxy_call(vfs, MP_QSTR_umount, 0, NULL);
+
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_1(mp_vfs_umount_obj, mp_vfs_umount);
+
+// Note: buffering and encoding args are currently ignored
+mp_obj_t mp_vfs_open(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_file, ARG_mode, ARG_encoding };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_file, MP_ARG_OBJ | MP_ARG_REQUIRED, {.u_rom_obj = MP_ROM_PTR(&mp_const_none_obj)} },
+        { MP_QSTR_mode, MP_ARG_OBJ, {.u_rom_obj = MP_ROM_QSTR(MP_QSTR_r)} },
+        { MP_QSTR_buffering, MP_ARG_INT, {.u_int = -1} },
+        { MP_QSTR_encoding, MP_ARG_OBJ, {.u_rom_obj = MP_ROM_PTR(&mp_const_none_obj)} },
+    };
+
+    // parse args
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    mp_vfs_mount_t *vfs = lookup_path((mp_obj_t)args[ARG_file].u_rom_obj, &args[ARG_file].u_obj);
+    return mp_vfs_proxy_call(vfs, MP_QSTR_open, 2, (mp_obj_t*)&args);
+}
+MP_DEFINE_CONST_FUN_OBJ_KW(mp_vfs_open_obj, 0, mp_vfs_open);
+
+mp_obj_t mp_vfs_chdir(mp_obj_t path_in) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path_in, &path_out);
+    MP_STATE_VM(vfs_cur) = vfs;
+    if (vfs == MP_VFS_ROOT) {
+        // If we change to the root dir and a VFS is mounted at the root then
+        // we must change that VFS's current dir to the root dir so that any
+        // subsequent relative paths begin at the root of that VFS.
+        for (vfs = MP_STATE_VM(vfs_mount_table); vfs != NULL; vfs = vfs->next) {
+            if (vfs->len == 1) {
+                mp_obj_t root = mp_obj_new_str("/", 1, false);
+                mp_vfs_proxy_call(vfs, MP_QSTR_chdir, 1, &root);
+                break;
+            }
+        }
+    } else {
+        mp_vfs_proxy_call(vfs, MP_QSTR_chdir, 1, &path_out);
+    }
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_1(mp_vfs_chdir_obj, mp_vfs_chdir);
+
+mp_obj_t mp_vfs_getcwd(void) {
+    if (MP_STATE_VM(vfs_cur) == MP_VFS_ROOT) {
+        return MP_OBJ_NEW_QSTR(MP_QSTR__slash_);
+    }
+    mp_obj_t cwd_o = mp_vfs_proxy_call(MP_STATE_VM(vfs_cur), MP_QSTR_getcwd, 0, NULL);
+    if (MP_STATE_VM(vfs_cur)->len == 1) {
+        // don't prepend "/" for vfs mounted at root
+        return cwd_o;
+    }
+    const char *cwd = mp_obj_str_get_str(cwd_o);
+    vstr_t vstr;
+    vstr_init(&vstr, MP_STATE_VM(vfs_cur)->len + strlen(cwd) + 1);
+    vstr_add_strn(&vstr, MP_STATE_VM(vfs_cur)->str, MP_STATE_VM(vfs_cur)->len);
+    if (!(cwd[0] == '/' && cwd[1] == 0)) {
+        vstr_add_str(&vstr, cwd);
+    }
+    return mp_obj_new_str_from_vstr(&mp_type_str, &vstr);
+}
+MP_DEFINE_CONST_FUN_OBJ_0(mp_vfs_getcwd_obj, mp_vfs_getcwd);
+
+typedef struct _mp_vfs_ilistdir_it_t {
+    mp_obj_base_t base;
+    mp_fun_1_t iternext;
+    union {
+        mp_vfs_mount_t *vfs;
+        mp_obj_t iter;
+    } cur;
+    bool is_str;
+    bool is_iter;
+} mp_vfs_ilistdir_it_t;
+
+STATIC mp_obj_t mp_vfs_ilistdir_it_iternext(mp_obj_t self_in) {
+    mp_vfs_ilistdir_it_t *self = MP_OBJ_TO_PTR(self_in);
+    if (self->is_iter) {
+        // continue delegating to root dir
+        return mp_iternext(self->cur.iter);
+    } else if (self->cur.vfs == NULL) {
+        // finished iterating mount points and no root dir is mounted
+        return MP_OBJ_STOP_ITERATION;
+    } else {
+        // continue iterating mount points
+        mp_vfs_mount_t *vfs = self->cur.vfs;
+        self->cur.vfs = vfs->next;
+        if (vfs->len == 1) {
+            // vfs is mounted at root dir, delegate to it
+            mp_obj_t root = mp_obj_new_str("/", 1, false);
+            self->is_iter = true;
+            self->cur.iter = mp_vfs_proxy_call(vfs, MP_QSTR_ilistdir, 1, &root);
+            return mp_iternext(self->cur.iter);
+        } else {
+            // a mounted directory
+            mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(3, NULL));
+            t->items[0] = mp_obj_new_str_of_type(
+                self->is_str ? &mp_type_str : &mp_type_bytes,
+                (const byte*)vfs->str + 1, vfs->len - 1);
+            t->items[1] = MP_OBJ_NEW_SMALL_INT(MP_S_IFDIR);
+            t->items[2] = MP_OBJ_NEW_SMALL_INT(0); // no inode number
+            return MP_OBJ_FROM_PTR(t);
+        }
+    }
+}
+
+mp_obj_t mp_vfs_ilistdir(size_t n_args, const mp_obj_t *args) {
+    mp_obj_t path_in;
+    if (n_args == 1) {
+        path_in = args[0];
+    } else {
+        path_in = MP_OBJ_NEW_QSTR(MP_QSTR_);
+    }
+
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path_in, &path_out);
+
+    if (vfs == MP_VFS_ROOT) {
+        // list the root directory
+        mp_vfs_ilistdir_it_t *iter = m_new_obj(mp_vfs_ilistdir_it_t);
+        iter->base.type = &mp_type_polymorph_iter;
+        iter->iternext = mp_vfs_ilistdir_it_iternext;
+        iter->cur.vfs = MP_STATE_VM(vfs_mount_table);
+        iter->is_str = mp_obj_get_type(path_in) == &mp_type_str;
+        iter->is_iter = false;
+        return MP_OBJ_FROM_PTR(iter);
+    }
+
+    return mp_vfs_proxy_call(vfs, MP_QSTR_ilistdir, 1, &path_out);
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_vfs_ilistdir_obj, 0, 1, mp_vfs_ilistdir);
+
+mp_obj_t mp_vfs_listdir(size_t n_args, const mp_obj_t *args) {
+    mp_obj_t iter = mp_vfs_ilistdir(n_args, args);
+    mp_obj_t dir_list = mp_obj_new_list(0, NULL);
+    mp_obj_t next;
+    while ((next = mp_iternext(iter)) != MP_OBJ_STOP_ITERATION) {
+        mp_obj_t *items;
+        mp_obj_get_array_fixed_n(next, 3, &items);
+        mp_obj_list_append(dir_list, items[0]);
+    }
+    return dir_list;
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_vfs_listdir_obj, 0, 1, mp_vfs_listdir);
+
+mp_obj_t mp_vfs_mkdir(mp_obj_t path_in) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path_in, &path_out);
+    if (vfs == MP_VFS_ROOT || (vfs != MP_VFS_NONE && !strcmp(mp_obj_str_get_str(path_out), "/"))) {
+        mp_raise_OSError(MP_EEXIST);
+    }
+    return mp_vfs_proxy_call(vfs, MP_QSTR_mkdir, 1, &path_out);
+}
+MP_DEFINE_CONST_FUN_OBJ_1(mp_vfs_mkdir_obj, mp_vfs_mkdir);
+
+mp_obj_t mp_vfs_remove(mp_obj_t path_in) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path_in, &path_out);
+    return mp_vfs_proxy_call(vfs, MP_QSTR_remove, 1, &path_out);
+}
+MP_DEFINE_CONST_FUN_OBJ_1(mp_vfs_remove_obj, mp_vfs_remove);
+
+mp_obj_t mp_vfs_rename(mp_obj_t old_path_in, mp_obj_t new_path_in) {
+    mp_obj_t args[2];
+    mp_vfs_mount_t *old_vfs = lookup_path(old_path_in, &args[0]);
+    mp_vfs_mount_t *new_vfs = lookup_path(new_path_in, &args[1]);
+    if (old_vfs != new_vfs) {
+        // can't rename across filesystems
+        mp_raise_OSError(MP_EPERM);
+    }
+    return mp_vfs_proxy_call(old_vfs, MP_QSTR_rename, 2, args);
+}
+MP_DEFINE_CONST_FUN_OBJ_2(mp_vfs_rename_obj, mp_vfs_rename);
+
+mp_obj_t mp_vfs_rmdir(mp_obj_t path_in) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path_in, &path_out);
+    return mp_vfs_proxy_call(vfs, MP_QSTR_rmdir, 1, &path_out);
+}
+MP_DEFINE_CONST_FUN_OBJ_1(mp_vfs_rmdir_obj, mp_vfs_rmdir);
+
+mp_obj_t mp_vfs_stat(mp_obj_t path_in) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path_in, &path_out);
+    if (vfs == MP_VFS_ROOT) {
+        mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(10, NULL));
+        t->items[0] = MP_OBJ_NEW_SMALL_INT(MP_S_IFDIR); // st_mode
+        for (int i = 1; i <= 9; ++i) {
+            t->items[i] = MP_OBJ_NEW_SMALL_INT(0); // dev, nlink, uid, gid, size, atime, mtime, ctime
+        }
+        return MP_OBJ_FROM_PTR(t);
+    }
+    return mp_vfs_proxy_call(vfs, MP_QSTR_stat, 1, &path_out);
+}
+MP_DEFINE_CONST_FUN_OBJ_1(mp_vfs_stat_obj, mp_vfs_stat);
+
+mp_obj_t mp_vfs_statvfs(mp_obj_t path_in) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path_in, &path_out);
+    if (vfs == MP_VFS_ROOT) {
+        // statvfs called on the root directory, see if there's anything mounted there
+        for (vfs = MP_STATE_VM(vfs_mount_table); vfs != NULL; vfs = vfs->next) {
+            if (vfs->len == 1) {
+                break;
+            }
+        }
+
+        // If there's nothing mounted at root then return a mostly-empty tuple
+        if (vfs == NULL) {
+            mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(10, NULL));
+
+            // fill in: bsize, frsize, blocks, bfree, bavail, files, ffree, favail, flags
+            for (int i = 0; i <= 8; ++i) {
+                t->items[i] = MP_OBJ_NEW_SMALL_INT(0);
+            }
+
+            // Put something sensible in f_namemax
+            t->items[9] = MP_OBJ_NEW_SMALL_INT(MICROPY_ALLOC_PATH_MAX);
+
+            return MP_OBJ_FROM_PTR(t);
+        }
+
+        // VFS mounted at root so delegate the call to it
+        path_out = MP_OBJ_NEW_QSTR(MP_QSTR__slash_);
+    }
+    return mp_vfs_proxy_call(vfs, MP_QSTR_statvfs, 1, &path_out);
+}
+MP_DEFINE_CONST_FUN_OBJ_1(mp_vfs_statvfs_obj, mp_vfs_statvfs);
+
+#endif // MICROPY_VFS