circuitpython/extmod/vfs.c

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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
#include <stdint.h>
#include <string.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
// For mp_vfs_proxy_call, the maximum number of additional args that can be passed.
// A fixed maximum size is used to avoid the need for a costly variable array.
#define PROXY_MAX_ARGS (2)
// 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;
*path_out = mp_const_none;
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) {
assert(n_args <= PROXY_MAX_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[2 + PROXY_MAX_ARGS];
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 the mounted object has the VFS protocol, call its import_stat helper
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
2019-12-03 15:50:37 -05:00
const mp_vfs_proto_t *proto = (mp_vfs_proto_t*)mp_proto_get(MP_QSTR_protocol_vfs, vfs->obj);
if (proto != NULL) {
return proto->import_stat(MP_OBJ_TO_PTR(vfs->obj), path_out);
}
// delegate to vfs.stat() method
mp_obj_t path_o = mp_obj_new_str(path_out, strlen(path_out));
mp_obj_t stat;
nlr_buf_t nlr;
if (nlr_push(&nlr) == 0) {
stat = mp_vfs_proxy_call(vfs, MP_QSTR_stat, 1, &path_o);
nlr_pop();
} else {
// assume an exception means that the path is not found
return MP_IMPORT_STAT_NO_EXIST;
}
mp_obj_t *items;
mp_obj_get_array_fixed_n(stat, 10, &items);
mp_int_t st_mode = mp_obj_get_int(items[0]);
if (st_mode & MP_S_IFDIR) {
return MP_IMPORT_STAT_DIR;
} else {
return MP_IMPORT_STAT_FILE;
}
}
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_rom_obj = MP_ROM_PTR(&mp_const_false_obj)} },
{ MP_QSTR_mkfs, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_PTR(&mp_const_false_obj)} },
};
// 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, &vfs_obj, NULL);
#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(args[ARG_file].u_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_QSTR(MP_QSTR__slash_);
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);
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_QSTR(MP_QSTR__slash_);
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_const_none;
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_list_append(dir_list, mp_obj_subscr(next, MP_OBJ_NEW_SMALL_INT(0), MP_OBJ_SENTINEL));
}
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_const_none;
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