readlink -f from busybox is broken for kernel version < 3.6

[honk0504]

Device: Nexus 7 (2013) WiFi (flo)
Android version: Android 11 (lineage 18.1 - lineage-18.1-20220228-nightly-flox-signed)
Magisk version name: 7cfce9f
Magisk version code: 24201

I patched the boot.img and got an magisk patched boot file. I booted into TWRP (twrp-3.6.0_9-0-flo) and installed the patched boot image. No errors. After booting the device freeze. I have to re-install org boot.img to make it work again.
I took magisk.apk and renamed it to magisk.zip. I trying to install magisk.zip with TWRP.
ERROR!

Magisk 24.2 Installer

! Cannot mount /system
'- Unmount partition
Prozess Updater endet mit FEHLER: 1
Fehler beim Installieren von ZIP '/sdcard/Download/magisk-v24.2.zip'
Partitions-Informationen werden aktualisiert...
... Fertig

[osm0sis]

More than likely this: #5516

It's already fixed for the next Canary and point release.

[osm0sis]

Oh wait, that recovery install issue is new..

I recall this used to work fine.

[disc0nct]

Same error!, I had to re-flash Magisk v24.1 back to make it work again.

[Displax]

Duplicate #5439
But nobody seems to want fix it...

[osm0sis]

It used to work though, so still should

[schneemaier]

I have the same issue

[StickyDigit]

Same here on Flox with LOS 18.1.

Magisk 24.2 resulted in stuck boot. Reinstalled 24.1 via TWRP. All ok.

Magisk 24.3 updated from app and worked, but did not survive routine LOS firmware update via TWRP.

24.3 wouldn't re-install from TWRP (couldn't find /system after umount). Had to reinstall 24.1 with TWRP, then update to 24.3 from the app.

[canyie]

Reverting busybox binary can fix this issue. Further investigation tells the busybox's readlink command with -f option doesn't work for now.


I guess the upgrade of ndk triggers some bugs in busybox.

[StickyDigit]

Following, I adb'd into twrp (3.5.2_9.0)

~ # busybox  | grep "BusyBox v"
BusyBox v1.22.1 bionic (2021-04-06 01:17 +0000) multi-call binary.

~ # echo ":$( readlink /system ):"
:/system_root/system:

~ # echo ":$( readlink -f /system ):"
::

"readlink -f" fails as you describe. Returns empty. FWIW, readlink -f /system || echo bad, echoes bad.
TWRP has not changed, and AFAIK the busybox is in/from that.
The same "readlink -f" is in util_functions.sh find_block() on 24.1, which somehow installs ok on TWRP.

[osm0sis]

Magisk's busybox (in its apk/zip) is where the regression lies, TWRP's busybox has no effect on it.

[yujincheng08]

This is because of android/ndk#1260

[osm0sis]

That issue sounds pretty old, though, and might not directly affect a static busybox? Also interesting how it worked fine in Magisk 24.1.

[yujincheng08]

@osm0sis I have fixed it. But I need you to make the change to busybox kitchen. Could you help me?

[osm0sis]

Nice! Same as here on Magisk repo we don't merge without John, but I can review PRs, etc.

[yujincheng08]

(off topic: could you review #5618?

[yujincheng08]

Try artifacts of #5620.

[osm0sis]

(off topic: could you review #5618?

Running it already as we speak, and taking a look. 👍

[Displax]

Can confirm this patch fix installation from TWRP. But not fix #5555, magisk still half-workable. su works, but other stuff broken (logs, normal setup, additional setup, etc.).
Log from #5620 : log.txt

[osm0sis]

Try artifacts of #5620.

Can also confirm this fixes flashing in flox TWRP. The PR CI build and 24303 both have broken root on flox however, but I can also confirm that's fixed upstream by the latest CI. 👍

recovery.log

@yujincheng08 if you rebase on HEAD I can try it again and make sure all is fully working with addon.d, etc. 🙌

[osm0sis]

Follow-up: Not a complete test, but I was able to try out addon.d by copying the arm busybox from your PR CI build over a HEAD CI installation's /data/adb/magisk/busybox and all worked perfectly. 🎉

[yujincheng08]

Fixed here: b1faa5e

[arch-user-france1]

Still no new release.. How can I get this patch?

[osm0sis]

Wait patiently or run the latest CI build from GitHub Actions.

[tfft]

Based on the number of people that have noted this issue/problem/bug and have downgraded, it might make sense to spin-off a 24.3.1 release simply to address this one problem allowing ample time for 24.4 to run its course.

[vvb2060]

Magisk/native/src/base/files.rs

Lines 81 to 91 in e327565

	pub fn realpath(path: &CStr, buf: &mut [u8]) -> isize {
	if let Some(fd) = open_fd!(path, O_PATH | O_CLOEXEC) {
	let mut st1: libc::stat;
	let mut st2: libc::stat;
	unsafe {
	st1 = std::mem::zeroed();
	if libc::fstat(fd.as_raw_fd(), &mut st1) < 0 {
	*errno() = ENOENT;
	return -1;
	}
	}

regression on 25204