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 <errno.h>
20 #include <pthread.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
read_block_file(void * cookie,uint32_t block,uint8_t * buffer,uint32_t fetch_size)35 static int read_block_file(void* cookie, uint32_t block, uint8_t* buffer, uint32_t fetch_size) {
36 struct file_data* fd = (struct file_data*)cookie;
37
38 if (lseek(fd->fd, block * fd->block_size, SEEK_SET) < 0) {
39 printf("seek on sdcard failed: %s\n", strerror(errno));
40 return -EIO;
41 }
42
43 while (fetch_size > 0) {
44 ssize_t r = read(fd->fd, buffer, fetch_size);
45 if (r < 0) {
46 if (r != -EINTR) {
47 printf("read on sdcard failed: %s\n", strerror(errno));
48 return -EIO;
49 }
50 r = 0;
51 }
52 fetch_size -= r;
53 buffer += r;
54 }
55
56 return 0;
57 }
58
close_file(void * cookie)59 static void close_file(void* cookie) {
60 struct file_data* fd = (struct file_data*)cookie;
61 close(fd->fd);
62 }
63
64 struct token {
65 pthread_t th;
66 const char* path;
67 int result;
68 };
69
run_sdcard_fuse(void * cookie)70 static void* run_sdcard_fuse(void* cookie) {
71 struct token* t = (struct token*)cookie;
72
73 struct stat sb;
74 if (stat(t->path, &sb) < 0) {
75 fprintf(stderr, "failed to stat %s: %s\n", t->path, strerror(errno));
76 t->result = -1;
77 return NULL;
78 }
79
80 struct file_data fd;
81 struct provider_vtab vtab;
82
83 fd.fd = open(t->path, O_RDONLY);
84 if (fd.fd < 0) {
85 fprintf(stderr, "failed to open %s: %s\n", t->path, strerror(errno));
86 t->result = -1;
87 return NULL;
88 }
89 fd.file_size = sb.st_size;
90 fd.block_size = 65536;
91
92 vtab.read_block = read_block_file;
93 vtab.close = close_file;
94
95 t->result = run_fuse_sideload(&vtab, &fd, fd.file_size, fd.block_size);
96 return NULL;
97 }
98
99 // How long (in seconds) we wait for the fuse-provided package file to
100 // appear, before timing out.
101 #define SDCARD_INSTALL_TIMEOUT 10
102
start_sdcard_fuse(const char * path)103 void* start_sdcard_fuse(const char* path) {
104 struct token* t = malloc(sizeof(struct token));
105
106 t->path = path;
107 pthread_create(&(t->th), NULL, run_sdcard_fuse, t);
108
109 struct stat st;
110 int i;
111 for (i = 0; i < SDCARD_INSTALL_TIMEOUT; ++i) {
112 if (stat(FUSE_SIDELOAD_HOST_PATHNAME, &st) != 0) {
113 if (errno == ENOENT && i < SDCARD_INSTALL_TIMEOUT-1) {
114 sleep(1);
115 continue;
116 } else {
117 return NULL;
118 }
119 }
120 }
121
122 // The installation process expects to find the sdcard unmounted.
123 // Unmount it with MNT_DETACH so that our open file continues to
124 // work but new references see it as unmounted.
125 umount2("/sdcard", MNT_DETACH);
126
127 return t;
128 }
129
finish_sdcard_fuse(void * cookie)130 void finish_sdcard_fuse(void* cookie) {
131 if (cookie == NULL) return;
132 struct token* t = (struct token*)cookie;
133
134 // Calling stat() on this magic filename signals the fuse
135 // filesystem to shut down.
136 struct stat st;
137 stat(FUSE_SIDELOAD_HOST_EXIT_PATHNAME, &st);
138
139 pthread_join(t->th, NULL);
140 free(t);
141 }
142