1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <stdlib.h> 18 #include <stdio.h> 19 #include <string.h> 20 #include <errno.h> 21 #include <sys/mount.h> 22 #include <sys/stat.h> 23 #include <unistd.h> 24 #include <fcntl.h> 25 26 #include "fuse_sideload.h" 27 28 struct file_data { 29 int fd; // the underlying sdcard file 30 31 uint64_t file_size; 32 uint32_t block_size; 33 }; 34 35 static int read_block_file(void* cookie, uint32_t block, uint8_t* buffer, uint32_t fetch_size) { 36 file_data* fd = reinterpret_cast<file_data*>(cookie); 37 38 off64_t offset = ((off64_t) block) * fd->block_size; 39 if (TEMP_FAILURE_RETRY(lseek64(fd->fd, offset, SEEK_SET)) == -1) { 40 fprintf(stderr, "seek on sdcard failed: %s\n", strerror(errno)); 41 return -EIO; 42 } 43 44 while (fetch_size > 0) { 45 ssize_t r = TEMP_FAILURE_RETRY(read(fd->fd, buffer, fetch_size)); 46 if (r == -1) { 47 fprintf(stderr, "read on sdcard failed: %s\n", strerror(errno)); 48 return -EIO; 49 } 50 fetch_size -= r; 51 buffer += r; 52 } 53 54 return 0; 55 } 56 57 static void close_file(void* cookie) { 58 file_data* fd = reinterpret_cast<file_data*>(cookie); 59 close(fd->fd); 60 } 61 62 bool start_sdcard_fuse(const char* path) { 63 struct stat sb; 64 if (stat(path, &sb) == -1) { 65 fprintf(stderr, "failed to stat %s: %s\n", path, strerror(errno)); 66 return false; 67 } 68 69 file_data fd; 70 fd.fd = open(path, O_RDONLY); 71 if (fd.fd == -1) { 72 fprintf(stderr, "failed to open %s: %s\n", path, strerror(errno)); 73 return false; 74 } 75 fd.file_size = sb.st_size; 76 fd.block_size = 65536; 77 78 provider_vtab vtab; 79 vtab.read_block = read_block_file; 80 vtab.close = close_file; 81 82 // The installation process expects to find the sdcard unmounted. 83 // Unmount it with MNT_DETACH so that our open file continues to 84 // work but new references see it as unmounted. 85 umount2("/sdcard", MNT_DETACH); 86 87 return run_fuse_sideload(&vtab, &fd, fd.file_size, fd.block_size) == 0; 88 } 89
