DroidDeck/tools/proot/PATCHES.md

proot patches carried by the app

Built by tools/proot/build.sh with the NDK on top of termux/proot 4dba3afb (Termux's 5.1.107-70 package, the proot the Linux runtime ships at opt/android-host/proot; every file.c:line site in that binary matches this commit). talloc is linked in statically from Samba's release tarball, so the apk carries one self-contained libproot.so plus libproot-loader.so, and LinuxRuntime prefers them over the runtime's copy.

Ported from WinNative (feature/proot-enhancements, e7af0f24):

• 0001-tracee-lookup-by-pid.patch - tracees are hashed by pid, so each ptrace stop finds its tracee without walking one list entry per thread, and terminated tracees are swept only after a termination.
• 0002-canon-resolve-parent-at-once.patch - a clean absolute guest path at least three directories deep under the rootfs binding alone has its parent opened once with O_PATH and taken as canonical when /proc/self/fd names the path proot would build, replacing an lstat per component. The final component of a call that does not follow it is no longer lstated. Extensions still see the parent's host path, and the fast path stays off while the f2fs workaround is active.
• 0003-clone3-flags-read-guard.patch - a thread created with clone3 keeps the flags it inherited when struct clone_args cannot be read, instead of being tracked as a fork.

Ported from WinNative (main, 53836ca9, "Fix/performance and vac"):

• 0004-seccomp-filter-by-argument.patch - the seccomp filter traces prctl only for PR_SET_DUMPABLE, setrlimit only for RLIMIT_STACK and prlimit64 only when it sets a new RLIMIT_STACK, the only cases proot acts on; every other call runs without a stop. uname is traced by the core only on x86_64, the one arch it rewrites; kompat still adds it for --kernel-release.
• 0005-seccomp-skip-unneeded-sysexit.patch - a seccomp stop fetches the registers once and looks the filter flags up by syscall number, instead of a PTRACE_GETEVENTMSG and a second register fetch. The flags table is built from proot's list merged with the enabled extensions' (kompat and fake_id0 here), so it is exactly what the filter reports. wait4/waitpid left to the kernel and accept/accept4 without a sockaddr skip their exit stop, unless an extension replaced the syscall (kompat turning accept4 into accept).
• 0006-clone3-exit-signal.patch - clone3 flags and exit signal are read as the 64-bit fields of struct clone_args, so a clone3 fork is told apart from a thread when proot decides how the child is traced.
• 0007-proc-self-thread-group.patch - tracees track their thread group, /proc/self names it instead of the calling thread, and /proc/thread-self resolves to /proc/<tgid>/task/<tid>.
• 0008-fchmodat2-openat2.patch - fchmodat2 paths are translated (honouring AT_SYMLINK_NOFOLLOW), openat2 answers ENOSYS so callers fall back to the translated openat, and syscall numbers past the end of a table are rejected instead of read.
• 0009-tracee-relatives-sweep.patch - tracees count their children, so a terminating thread with no children or ptracees no longer walks every tracee; the per-stop memory collector is emptied instead of freed and reallocated.

Added for Flatpak:

• 0010-new-mount-api-enosys.patch - open_tree, move_mount, fspick and mount_setattr answer ENOSYS. They take paths proot never translated, so libglnx's open_tree(AT_FDCWD, "/") handed Flatpak a descriptor for the host's root and it tried to create directories there (mkdirat(root): Operation not permitted); unsupported, libglnx falls back to openat.