circuitpython/extmod/vfs.h

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2020-06-03 18:40:05 -04:00
// SPDX-FileCopyrightText: 2014 MicroPython & CircuitPython contributors (https://github.com/adafruit/circuitpython/graphs/contributors)
// SPDX-FileCopyrightText: Copyright (c) 2017 Damien P. George
//
// SPDX-License-Identifier: MIT
#ifndef MICROPY_INCLUDED_EXTMOD_VFS_H
#define MICROPY_INCLUDED_EXTMOD_VFS_H
#include "py/lexer.h"
#include "py/obj.h"
protocols: Allow them to be (optionally) type-safe Protocols are nice, but there is no way for C code to verify whether a type's "protocol" structure actually implements some particular protocol. As a result, you can pass an object that implements the "vfs" protocol to one that expects the "stream" protocol, and the opposite of awesomeness ensues. This patch adds an OPTIONAL (but enabled by default) protocol identifier as the first member of any protocol structure. This identifier is simply a unique QSTR chosen by the protocol designer and used by each protocol implementer. When checking for protocol support, instead of just checking whether the object's type has a non-NULL protocol field, use `mp_proto_get` which implements the protocol check when possible. The existing protocols are now named: protocol_framebuf protocol_i2c protocol_pin protocol_stream protocol_spi protocol_vfs (most of these are unused in CP and are just inherited from MP; vfs and stream are definitely used though) I did not find any crashing examples, but here's one to give a flavor of what is improved, using `micropython_coverage`. Before the change, the vfs "ioctl" protocol is invoked, and the result is not intelligible as json (but it could have resulted in a hard fault, potentially): >>> import uos, ujson >>> u = uos.VfsPosix('/tmp') >>> ujson.load(u) Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: syntax error in JSON After the change, the vfs object is correctly detected as not supporting the stream protocol: >>> ujson.load(p) Traceback (most recent call last): File "<stdin>", line 1, in <module> OSError: stream operation not supported
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#include "py/proto.h"
// return values of mp_vfs_lookup_path
// ROOT is 0 so that the default current directory is the root directory
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#define MP_VFS_NONE ((mp_vfs_mount_t *)1)
#define MP_VFS_ROOT ((mp_vfs_mount_t *)0)
// MicroPython's port-standardized versions of stat constants
#define MP_S_IFDIR (0x4000)
#define MP_S_IFREG (0x8000)
// these are the values for mp_vfs_blockdev_t.flags
#define MP_BLOCKDEV_FLAG_NATIVE (0x0001) // readblocks[2]/writeblocks[2] contain native func
#define MP_BLOCKDEV_FLAG_FREE_OBJ (0x0002) // fs_user_mount_t obj should be freed on umount
#define MP_BLOCKDEV_FLAG_HAVE_IOCTL (0x0004) // new protocol with ioctl
#define MP_BLOCKDEV_FLAG_NO_FILESYSTEM (0x0008) // the block device has no filesystem on it
// Device is writable over USB and read-only to MicroPython.
#define MP_BLOCKDEV_FLAG_USB_WRITABLE (0x0010)
// Bit set when the above flag is checked before opening a file for write.
#define MP_BLOCKDEV_FLAG_CONCURRENT_WRITE_PROTECTED (0x0020)
// constants for block protocol ioctl
#define MP_BLOCKDEV_IOCTL_INIT (1)
#define MP_BLOCKDEV_IOCTL_DEINIT (2)
#define MP_BLOCKDEV_IOCTL_SYNC (3)
#define MP_BLOCKDEV_IOCTL_BLOCK_COUNT (4)
#define MP_BLOCKDEV_IOCTL_BLOCK_SIZE (5)
#define MP_BLOCKDEV_IOCTL_BLOCK_ERASE (6)
// At the moment the VFS protocol just has import_stat, but could be extended to other methods
typedef struct _mp_vfs_proto_t {
protocols: Allow them to be (optionally) type-safe Protocols are nice, but there is no way for C code to verify whether a type's "protocol" structure actually implements some particular protocol. As a result, you can pass an object that implements the "vfs" protocol to one that expects the "stream" protocol, and the opposite of awesomeness ensues. This patch adds an OPTIONAL (but enabled by default) protocol identifier as the first member of any protocol structure. This identifier is simply a unique QSTR chosen by the protocol designer and used by each protocol implementer. When checking for protocol support, instead of just checking whether the object's type has a non-NULL protocol field, use `mp_proto_get` which implements the protocol check when possible. The existing protocols are now named: protocol_framebuf protocol_i2c protocol_pin protocol_stream protocol_spi protocol_vfs (most of these are unused in CP and are just inherited from MP; vfs and stream are definitely used though) I did not find any crashing examples, but here's one to give a flavor of what is improved, using `micropython_coverage`. Before the change, the vfs "ioctl" protocol is invoked, and the result is not intelligible as json (but it could have resulted in a hard fault, potentially): >>> import uos, ujson >>> u = uos.VfsPosix('/tmp') >>> ujson.load(u) Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: syntax error in JSON After the change, the vfs object is correctly detected as not supporting the stream protocol: >>> ujson.load(p) Traceback (most recent call last): File "<stdin>", line 1, in <module> OSError: stream operation not supported
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MP_PROTOCOL_HEAD
mp_import_stat_t (*import_stat)(void *self, const char *path);
} mp_vfs_proto_t;
typedef struct _mp_vfs_blockdev_t {
uint16_t flags;
size_t block_size;
mp_obj_t readblocks[5];
mp_obj_t writeblocks[5];
// new protocol uses just ioctl, old uses sync (optional) and count
union {
mp_obj_t ioctl[4];
struct {
mp_obj_t sync[2];
mp_obj_t count[2];
} old;
} u;
} mp_vfs_blockdev_t;
typedef struct _mp_vfs_mount_t {
const char *str; // mount point with leading /
size_t len;
mp_obj_t obj;
struct _mp_vfs_mount_t *next;
} mp_vfs_mount_t;
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;
mp_obj_t mp_vfs_ilistdir_it_iternext(mp_obj_t self_in);
void mp_vfs_blockdev_init(mp_vfs_blockdev_t *self, mp_obj_t bdev);
int mp_vfs_blockdev_read(mp_vfs_blockdev_t *self, size_t block_num, size_t num_blocks, uint8_t *buf);
int mp_vfs_blockdev_read_ext(mp_vfs_blockdev_t *self, size_t block_num, size_t block_off, size_t len, uint8_t *buf);
int mp_vfs_blockdev_write(mp_vfs_blockdev_t *self, size_t block_num, size_t num_blocks, const uint8_t *buf);
int mp_vfs_blockdev_write_ext(mp_vfs_blockdev_t *self, size_t block_num, size_t block_off, size_t len, const uint8_t *buf);
mp_obj_t mp_vfs_blockdev_ioctl(mp_vfs_blockdev_t *self, uintptr_t cmd, uintptr_t arg);
mp_vfs_mount_t *mp_vfs_lookup_path(const char *path, const char **path_out);
mp_import_stat_t mp_vfs_import_stat(const char *path);
mp_obj_t mp_vfs_mount(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args);
mp_obj_t mp_vfs_umount(mp_obj_t mnt_in);
mp_obj_t mp_vfs_open(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args);
mp_obj_t mp_vfs_chdir(mp_obj_t path_in);
mp_obj_t mp_vfs_getcwd(void);
mp_obj_t mp_vfs_ilistdir(size_t n_args, const mp_obj_t *args);
mp_obj_t mp_vfs_listdir(size_t n_args, const mp_obj_t *args);
mp_obj_t mp_vfs_mkdir(mp_obj_t path_in);
mp_obj_t mp_vfs_remove(mp_obj_t path_in);
mp_obj_t mp_vfs_rename(mp_obj_t old_path_in, mp_obj_t new_path_in);
mp_obj_t mp_vfs_rmdir(mp_obj_t path_in);
mp_obj_t mp_vfs_stat(mp_obj_t path_in);
mp_obj_t mp_vfs_statvfs(mp_obj_t path_in);
int mp_vfs_mount_and_chdir_protected(mp_obj_t bdev, mp_obj_t mount_point);
mp_obj_t mp_vfs_ilistdir_it_iternext(mp_obj_t self_in);
MP_DECLARE_CONST_FUN_OBJ_KW(mp_vfs_mount_obj);
MP_DECLARE_CONST_FUN_OBJ_1(mp_vfs_umount_obj);
MP_DECLARE_CONST_FUN_OBJ_KW(mp_vfs_open_obj);
MP_DECLARE_CONST_FUN_OBJ_1(mp_vfs_chdir_obj);
MP_DECLARE_CONST_FUN_OBJ_0(mp_vfs_getcwd_obj);
MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_vfs_ilistdir_obj);
MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_vfs_listdir_obj);
MP_DECLARE_CONST_FUN_OBJ_1(mp_vfs_mkdir_obj);
MP_DECLARE_CONST_FUN_OBJ_1(mp_vfs_remove_obj);
MP_DECLARE_CONST_FUN_OBJ_2(mp_vfs_rename_obj);
MP_DECLARE_CONST_FUN_OBJ_1(mp_vfs_rmdir_obj);
MP_DECLARE_CONST_FUN_OBJ_1(mp_vfs_stat_obj);
MP_DECLARE_CONST_FUN_OBJ_1(mp_vfs_statvfs_obj);
#endif // MICROPY_INCLUDED_EXTMOD_VFS_H