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-rw-r--r--fuse_sdcard_provider.cpp88
1 files changed, 88 insertions, 0 deletions
diff --git a/fuse_sdcard_provider.cpp b/fuse_sdcard_provider.cpp
new file mode 100644
index 000000000..df9631272
--- /dev/null
+++ b/fuse_sdcard_provider.cpp
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "fuse_sideload.h"
+
+struct file_data {
+ int fd; // the underlying sdcard file
+
+ uint64_t file_size;
+ uint32_t block_size;
+};
+
+static int read_block_file(void* cookie, uint32_t block, uint8_t* buffer, uint32_t fetch_size) {
+ file_data* fd = reinterpret_cast<file_data*>(cookie);
+
+ off64_t offset = ((off64_t) block) * fd->block_size;
+ if (TEMP_FAILURE_RETRY(lseek64(fd->fd, offset, SEEK_SET)) == -1) {
+ fprintf(stderr, "seek on sdcard failed: %s\n", strerror(errno));
+ return -EIO;
+ }
+
+ while (fetch_size > 0) {
+ ssize_t r = TEMP_FAILURE_RETRY(read(fd->fd, buffer, fetch_size));
+ if (r == -1) {
+ fprintf(stderr, "read on sdcard failed: %s\n", strerror(errno));
+ return -EIO;
+ }
+ fetch_size -= r;
+ buffer += r;
+ }
+
+ return 0;
+}
+
+static void close_file(void* cookie) {
+ file_data* fd = reinterpret_cast<file_data*>(cookie);
+ close(fd->fd);
+}
+
+bool start_sdcard_fuse(const char* path) {
+ struct stat sb;
+ if (stat(path, &sb) == -1) {
+ fprintf(stderr, "failed to stat %s: %s\n", path, strerror(errno));
+ return false;
+ }
+
+ file_data fd;
+ fd.fd = open(path, O_RDONLY);
+ if (fd.fd == -1) {
+ fprintf(stderr, "failed to open %s: %s\n", path, strerror(errno));
+ return false;
+ }
+ fd.file_size = sb.st_size;
+ fd.block_size = 65536;
+
+ provider_vtab vtab;
+ vtab.read_block = read_block_file;
+ vtab.close = close_file;
+
+ // The installation process expects to find the sdcard unmounted.
+ // Unmount it with MNT_DETACH so that our open file continues to
+ // work but new references see it as unmounted.
+ umount2("/sdcard", MNT_DETACH);
+
+ return run_fuse_sideload(&vtab, &fd, fd.file_size, fd.block_size) == 0;
+}