Split uos module into os and storage.

os is a subset of CPython's os. storage contains additional
file system mounting functionality based on UNIX's mount
management.

Fixes #140

2 files changed, 321 insertions, 0 deletions

diff --git a/shared-module/os/__init__.c b/shared-module/os/__init__.c
new file mode 100644
index 000000000..b628d4971
--- /dev/null
+++ b/shared-module/os/__init__.c
@@ -0,0 +1,188 @@
+/*
+ * 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) 2015 Josef Gajdusek
+ * Copyright (c) 2017 Scott Shawcroft for Adafruit Industries
+ *
+ * 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 <string.h>
+
+#include "extmod/vfs.h"
+#include "py/mperrno.h"
+#include "py/mpstate.h"
+#include "py/obj.h"
+#include "py/objstr.h"
+#include "py/runtime.h"
+#include "shared-bindings/os/__init__.h"
+
+// This provides all VFS related OS functions so that ports can share the code
+// as needed. It does not provide uname.
+
+// Version of mp_vfs_lookup_path that takes and returns uPy string objects.
+STATIC mp_vfs_mount_t *lookup_path(const char* path, mp_obj_t *path_out) {
+    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),
+            (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);
+}
+
+void common_hal_os_chdir(const char* path) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path, &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);
+    }
+}
+
+mp_obj_t common_hal_os_getcwd(void) {
+    return mp_vfs_getcwd();
+}
+
+mp_obj_t common_hal_os_listdir(const char* path) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path, &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) == &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);
+}
+
+void common_hal_os_mkdir(const char* path) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path, &path_out);
+    if (vfs == MP_VFS_ROOT || (vfs != MP_VFS_NONE && !strcmp(mp_obj_str_get_str(path_out), "/"))) {
+        mp_raise_OSError(MP_EEXIST);
+    }
+    mp_vfs_proxy_call(vfs, MP_QSTR_mkdir, 1, &path_out);
+}
+
+void common_hal_os_remove(const char* path) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path, &path_out);
+    mp_vfs_proxy_call(vfs, MP_QSTR_remove, 1, &path_out);
+}
+
+void common_hal_os_rename(const char* old_path, const char* new_path) {
+    mp_obj_t args[2];
+    mp_vfs_mount_t *old_vfs = lookup_path(old_path, &args[0]);
+    mp_vfs_mount_t *new_vfs = lookup_path(new_path, &args[1]);
+    if (old_vfs != new_vfs) {
+        // can't rename across filesystems
+        mp_raise_OSError(MP_EPERM);
+    }
+    mp_vfs_proxy_call(old_vfs, MP_QSTR_rename, 2, args);
+}
+
+void common_hal_os_rmdir(const char* path) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path, &path_out);
+    mp_vfs_proxy_call(vfs, MP_QSTR_rmdir, 1, &path_out);
+}
+
+mp_obj_t common_hal_os_stat(const char* path) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path, &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_obj_t common_hal_os_statvfs(const char* path) {
+    mp_obj_t path_out;
+    mp_vfs_mount_t *vfs = lookup_path(path, &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);
+}
diff --git a/shared-module/storage/__init__.c b/shared-module/storage/__init__.c
new file mode 100644
index 000000000..582b91a5b
--- /dev/null
+++ b/shared-module/storage/__init__.c
@@ -0,0 +1,133 @@
+/*
+ * 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) 2015 Josef Gajdusek
+ * Copyright (c) 2017 Scott Shawcroft for Adafruit Industries
+ *
+ * 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 <string.h>
+
+#include "extmod/vfs.h"
+#include "py/mperrno.h"
+#include "py/obj.h"
+#include "py/runtime.h"
+#include "shared-bindings/storage/__init__.h"
+
+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);
+}
+
+void common_hal_storage_mount(mp_obj_t vfs_obj, const char* mount_path, bool readonly) {
+    // create new object
+    mp_vfs_mount_t *vfs = m_new_obj(mp_vfs_mount_t);
+    vfs->str = mount_path;
+    vfs->len = strlen(mount_path);
+    vfs->obj = vfs_obj;
+    vfs->next = NULL;
+
+    mp_obj_t args[2];
+    args[0] = readonly ? mp_const_true : mp_const_false;
+    args[1] = mp_const_false; // Don't make the file system automatically when mounting.
+
+    // 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(mount_path, &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;
+}
+
+void common_hal_storage_umount_object(mp_obj_t vfs_obj) {
+    // remove vfs from the mount table
+    mp_vfs_mount_t *vfs = NULL;
+    for (mp_vfs_mount_t **vfsp = &MP_STATE_VM(vfs_mount_table); *vfsp != NULL; vfsp = &(*vfsp)->next) {
+        if ((*vfsp)->obj == vfs_obj) {
+            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);
+}
+
+void common_hal_storage_umount_path(const char* mount_path) {
+    // remove vfs from the mount table
+    mp_obj_t *vfs_obj = NULL;
+    for (mp_vfs_mount_t **vfsp = &MP_STATE_VM(vfs_mount_table); *vfsp != NULL; vfsp = &(*vfsp)->next) {
+        if (strcmp(mount_path, (*vfsp)->str) == 0) {
+            vfs_obj = (*vfsp)->obj;
+            break;
+        }
+    }
+
+    if (vfs_obj == NULL) {
+        mp_raise_OSError(MP_EINVAL);
+    }
+
+    common_hal_storage_umount_object(vfs_obj);
+}