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Use symlink to setup preinit

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This commit is contained in:
LoveSy 2024-07-17 23:03:37 +08:00 committed by John Wu
parent 2754b1dcf8
commit 0869a90fe3
1 changed files with 43 additions and 56 deletions
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99
native/src/core/mount.rs
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@ -49,16 +49,13 @@ pub fn setup_mounts() {
let preinit_dir = Utf8CStr::from_string(&mut preinit_dir);
let r: LoggedResult<()> = try {
FsPath::from(preinit_dir).mkdir(0o700)?;
mnt_path.mkdirs(0o755)?;
let mut buf = Utf8CStrBufArr::default();
if mnt_path.parent(&mut buf) {
FsPath::from(&buf).mkdirs(0o755)?;
}
mnt_path.remove().ok();
unsafe {
libc::mount(
preinit_dir.as_ptr(),
mnt_path.as_ptr(),
ptr::null(),
libc::MS_BIND,
ptr::null(),
)
.as_os_err()?
libc::symlink(preinit_dir.as_ptr(), mnt_path.as_ptr()).as_os_err()?
}
};
if r.is_ok() {
@ -134,14 +131,12 @@ pub fn setup_mounts() {
}
// when partitions have the same fs type, the order is:
// - preinit: it's selected previously, so it's always the first
// - data: it has sufficient space and can be safely written
// - cache: size is limited, but still can be safely written
// - metadata: size is limited, and it might cause unexpected behavior if written
// - persist: it's the last resort, as it's dangerous to write to it
#[derive(PartialEq, Eq, PartialOrd, Ord)]
enum PartId {
PreInit,
Data,
Cache,
Metadata,
@ -165,16 +160,10 @@ pub fn find_preinit_device() -> String {
} else {
EncryptType::File
};
let mount = unsafe { libc::getuid() } == 0 && std::env::var("MAGISKTMP").is_ok();
let make_dev = mount && std::env::var_os("MAKEDEV").is_some();
let mut matched_info = parse_mount_info("self")
.into_iter()
.filter_map(|info| {
// if preinit is already mounted, choose it unconditionally
if info.target.ends_with(PREINITMIRR) {
return Some((PartId::PreInit, info));
}
if info.root != "/" || !info.source.starts_with('/') || info.source.contains("/dm-") {
return None;
}
@ -222,47 +211,45 @@ pub fn find_preinit_device() -> String {
_ => ap.cmp(bp),
},
);
let preinit_source = match preinit_info {
(PartId::PreInit, info) => &info.source,
(_, info) => {
let mut target = info.target.clone();
let mut preinit_dir = resolve_preinit_dir(Utf8CStr::from_string(&mut target));
if mount && let Ok(tmp) = std::env::var("MAGISKTMP") {
let mut buf = Utf8CStrBufArr::default();
let mirror_dir = FsPathBuf::new(&mut buf).join(&tmp).join(PREINITMIRR);
let preinit_dir = FsPath::from(Utf8CStr::from_string(&mut preinit_dir));
let _: LoggedResult<()> = try {
preinit_dir.mkdirs(0o700)?;
mirror_dir.mkdirs(0o700)?;
unsafe {
libc::mount(
preinit_dir.as_ptr(),
mirror_dir.as_ptr(),
ptr::null(),
libc::MS_BIND,
ptr::null(),
)
.as_os_err()?;
}
};
if make_dev {
let dev_path = FsPathBuf::new(&mut buf).join(&tmp).join(PREINITDEV);
unsafe {
libc::mknod(
dev_path.as_ptr(),
libc::S_IFBLK | 0o600,
info.device as dev_t,
)
.as_os_err()
.log()
.ok();
}
}
let info = &preinit_info.1;
let mut target = info.target.clone();
let mut preinit_dir = resolve_preinit_dir(Utf8CStr::from_string(&mut target));
if unsafe { libc::getuid() } == 0
&& let Ok(tmp) = std::env::var("MAGISKTMP")
&& !tmp.is_empty()
{
let mut buf = Utf8CStrBufArr::default();
let mirror_dir = FsPathBuf::new(&mut buf).join(&tmp).join(PREINITMIRR);
let preinit_dir = FsPath::from(Utf8CStr::from_string(&mut preinit_dir));
let _: LoggedResult<()> = try {
preinit_dir.mkdirs(0o700)?;
let mut buf = Utf8CStrBufArr::default();
if mirror_dir.parent(&mut buf) {
FsPath::from(&buf).mkdirs(0o755)?;
}
mirror_dir.remove().ok();
unsafe {
libc::umount2(mirror_dir.as_ptr(), libc::MNT_DETACH)
.as_os_err()
.ok(); // ignore error
libc::symlink(preinit_dir.as_ptr(), mirror_dir.as_ptr()).as_os_err()?;
}
};
if std::env::var_os("MAKEDEV").is_some() {
let dev_path = FsPathBuf::new(&mut buf).join(&tmp).join(PREINITDEV);
unsafe {
libc::mknod(
dev_path.as_ptr(),
libc::S_IFBLK | 0o600,
info.device as dev_t,
)
.as_os_err()
.log()
.ok();
}
&info.source
}
};
Path::new(&preinit_source)
}
Path::new(&info.source)
.file_name()
.unwrap()
.to_str()