8d039f7bd8
Support for backing up and restoring user.default, user.inode_cache, and user.inode_code_cache xattrs introduced in Android 7.x Change-Id: I6e0aa7fc9cd30ed004ef28ebb58d60a82e518123
124 lines
3.4 KiB
C
124 lines
3.4 KiB
C
/*
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** Copyright 2008, The Android Open Source Project
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**
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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**
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** http://www.apache.org/licenses/LICENSE-2.0
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**
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <sys/types.h>
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#include <sys/xattr.h>
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#include <string.h>
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#include <linux/limits.h>
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#include <errno.h>
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#include "libtar.h"
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#include "android_utils.h"
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/* This code may come in handy later if we ever need to extend to storing more user.inode_* xattrs
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#define USER_INODE_SEPARATOR "\0"
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#define ANDROID_USER_INODE_XATTR_PREFIX "user.inode_"
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#define ANDROID_USER_INODE_XATTR_PREFIX_LEN strlen(ANDROID_USER_INODE_XATTR_PREFIX)
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char* scan_xattrs_for_user_inode (const char *realname, size_t *return_size)
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{
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ssize_t size;
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char xattr_list[PATH_MAX];
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size = listxattr(realname, xattr_list, sizeof(xattr_list));
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if (size < 0) {
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return NULL;
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}
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char xattr[T_BLOCKSIZE];
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char *xattr_ptr;
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int first = 1;
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*return_size = 0;
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for (int i = 0; i < size; i++) {
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if (xattr_list[i]) {
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xattr_ptr = xattr_list + i;
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if (strncmp(xattr_ptr, ANDROID_USER_INODE_XATTR_PREFIX, ANDROID_USER_INODE_XATTR_PREFIX_LEN) == 0) {
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// found a user.inode xattr
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if (first) {
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first = 0;
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strcpy(xattr, xattr_ptr);
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*return_size = strlen(xattr_ptr);
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} else {
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char *ptr = xattr + *return_size;
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snprintf(ptr, T_BLOCKSIZE - *return_size, "%s", xattr_ptr);
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*return_size += strlen(xattr_ptr) + 1; // + 1 for null separator
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if (*return_size >= T_BLOCKSIZE) {
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*return_size = 0;
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return NULL;
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}
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}
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}
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i += strlen(xattr_ptr);
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}
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}
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if (first)
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return NULL;
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return strdup(xattr);
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}*/
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/*
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* get_path_inode and write_path_inode were taken from frameworks/native/cmds/installd/utils.cpp
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*/
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static int get_path_inode(const char* path, ino_t *inode) {
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struct stat buf;
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memset(&buf, 0, sizeof(buf));
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if (stat(path, &buf) != 0) {
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printf("failed to stat %s\n", path);
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return -1;
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}
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*inode = buf.st_ino;
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return 0;
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}
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/**
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* Write the inode of a specific child file into the given xattr on the
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* parent directory. This allows you to find the child later, even if its
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* name is encrypted.
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*/
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int write_path_inode(const char* parent, const char* name, const char* inode_xattr) {
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ino_t inode = 0;
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uint64_t inode_raw = 0;
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char path[PATH_MAX];
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snprintf(path, PATH_MAX, "%s/%s", parent, name);
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if (mkdirhier(path) == -1) {
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printf("failed to mkdirhier for %s\n", path);
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return -1;
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}
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if (get_path_inode(path, &inode) != 0) {
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return -1;
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}
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// Check to see if already set correctly
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if (getxattr(parent, inode_xattr, &inode_raw, sizeof(inode_raw)) == sizeof(inode_raw)) {
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if (inode_raw == inode) {
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// Already set correctly; skip writing
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return 0;
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}
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}
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inode_raw = inode;
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printf("setting %s on %s pointing to %s\n", inode_xattr, parent, path);
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if (setxattr(parent, inode_xattr, &inode_raw, sizeof(inode_raw), 0) != 0 && errno != EOPNOTSUPP) {
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printf("Failed to write xattr %s at %s (%s)\n", inode_xattr, parent, strerror(errno));
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return -1;
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}
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return 0;
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}
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