我注意到android目录由符号链接组成,如下所示:
lrwxrwxrwx 1 root root 21 1970-01-01 08:00 /sdcard -> /storage/self/primary
lrwxrwxrwx 1 root root 19 1972-12-17 02:19 /storage/self/primary -> /mnt/user/0/primary
lrwxrwxrwx 1 root root 19 2020-02-21 10:31 /mnt/user/0/primary -> /storage/emulated/0
我搜索了一些android文档,发现:
[/sdcard -> /storage/self/primary
由system/core/rootdir/init.rc
中的命令创建:
symlink /storage/self/primary /sdcard
[/storage/self/
和/mnt/user/0/
被安装在system/vold/VolumeManager.cpp
中:
std::string storageSource;
if (mode == "default") {
storageSource = "/mnt/runtime/default";
} else if (mode == "read") {
storageSource = "/mnt/runtime/read";
} else if (mode == "write") {
storageSource = "/mnt/runtime/write";
} else if (mode == "full") {
storageSource = "/mnt/runtime/full";
} else {
// Sane default of no storage visible
_exit(0);
}
if (TEMP_FAILURE_RETRY(
mount(storageSource.c_str(), "/storage", NULL, MS_BIND | MS_REC, NULL)) == -1) {
PLOG(ERROR) << "Failed to mount " << storageSource << " for " << de->d_name;
_exit(1);
}
if (TEMP_FAILURE_RETRY(mount(NULL, "/storage", NULL, MS_REC | MS_SLAVE, NULL)) == -1) {
PLOG(ERROR) << "Failed to set MS_SLAVE to /storage for " << de->d_name;
_exit(1);
}
// Mount user-specific symlink helper into place
userid_t user_id = multiuser_get_user_id(uid);
std::string userSource(StringPrintf("/mnt/user/%d", user_id));
if (TEMP_FAILURE_RETRY(
mount(userSource.c_str(), "/storage/self", NULL, MS_BIND, NULL)) == -1) {
PLOG(ERROR) << "Failed to mount " << userSource << " for " << de->d_name;
_exit(1);
}
但是,我没有找到Android系统何时何地在primary
或/storage/self
中创建/mnt/user/0/self
目录。您能帮我解决问题吗?非常感谢!
也许您可以在VolumeManager.cpp中引用函数“ linkPrimary”。它将创建链接器/ mnt / user / 0 / primary-> / storage / emulated / 0