Paçoca

Posted on May 14

Running Native glibc (Debian) Binaries on Android 15 Without PRoot

#ai #terminal #compiling #termux

🔧 TL;DR: Android 15 broke PRoot with stricter seccomp filters. After ~10 hours of debugging, I found a working solution using patchelf + LD_PRELOAD= to run native Linux (Debian/glibc) binaries directly on Termux!

🎯 What will you achieve? (Click to expand)

By following this guide, you will be able to:

✅ Run GCC, Python, Bun, Git and 300+ more Debian packages natively
✅ Compile code directly on your Android phone
✅ Use Linux development tools without cloud dependencies
✅ Get a true Linux experience on mobile

The Problem

Android 15 significantly tightened its seccomp security filters. Running any Debian/glibc binary via proot-distro now fails with:

Bad system call (SIGSYS)
set_robust_list: Function not implemented

⚠️ Important: This isn't a configuration issue. The kernel literally blocks the syscalls that PRoot needs to emulate a Linux environment.

Every guide said "just use PRoot" → so I spent ~10 hours finding what actually works.

🤔 Why should you care about this? (Click to expand)

If you want to run Linux development tools on your Android device without relying on cloud services or complex setups, this guide is for you!

This solution works because we bypass PRoot entirely and run binaries natively using patchelf to modify the ELF binary's interpreter path.

Understanding Seccomp

🔒 What is Seccomp? (Click to learn)

Seccomp (Secure Computing Mode) is a Linux kernel security feature that:

Filters system calls (syscalls) a process can make
Restricts access to sensitive kernel operations
Prevents exploitation by limiting what programs can do

Think of it like a firewall for programs - it decides which "doors" a program can use.

📖 Learn more about seccomp (Red Hat Documentation)

The Solution — Three Tiers

I developed a three-tier approach depending on your needs:

📋 Click to see all solution tiers

Tier	Method	Root Required	Native Level	Best For
1	`LD_PRELOAD=` + direct binary	❌ No	⭐⭐⭐⭐⭐	Simple binaries
2	`su -c` wrapper with env vars	✅ Yes	⭐⭐⭐⭐	Complex binaries
3	Smart APT wrapper	✅ Yes	⭐⭐⭐	Package management

Tier 1 — Most Native (No Root)

# After patchelf on binary:
LD_PRELOAD= /path/to/glibc-binary "$@"

True native execution
The ELF binary loads glibc directly
LD_PRELOAD= prevents Termux from injecting its Bionic lib

Tier 2 — Production Stable (Root Required)

su -c "LD_PRELOAD= LD_LIBRARY_PATH=\$GLIBC/lib/aarch64-linux-gnu:\$GLIBC/usr/lib/aarch64-linux-gnu \
       \$GLIBC/usr/bin/binary \"\\\$@\""

More compatible for complex binaries
Handles deep transitive dependencies

Tier 3 — "Just Works" (Smart APT)

Transparent apt install that tries Termux repos first, falls back to Debian, and auto-patches new binaries.

Root Cause — Why PRoot Fails

🐛 The Three Problems (Click to expand)

Problem 1: Seccomp Blocking

Android 15 seccomp blocks set_robust_list called by glibc at startup → SIGSYS

📖 What is set_robust_list?

Problem 2: Termux LD_PRELOAD Conflict

Termux injects libtermux-exec-ld-preload.so into every process. This Bionic library looks for libc.so → which doesn't exist in glibc → crash.

Problem 3: Root-Created Symlink Permissions

Symlinks created by apt inside chroot (running as root) inherit security attributes that make them inaccessible to the Termux user UID.

Device Information

📱 My Device Setup (Click to see details)

💡 Samsung Variants Explained:

Exynos (Europe/Asia): Uses Samsung's own processor — our device!

Snapdragon (USA/LATAM/China): Uses Qualcomm processor — different kernel/firmware

Spec	Value
Device	Samsung Galaxy S10e (SM-G970F)
Variant	Exynos 9820 (International - EMEA)
Processor	Exynos 9820 - 8nm Octa-core
Architecture	ARM64 (AArch64)
Android	15
ROM	ExtremeROM Nexus by ExtremeXT
Root	KernelSU
Terminal	Termux (F-Droid)

Prerequisites

✅ Requirements Checklist (Click to expand)

Before we begin, make sure you have:

[ ] Rooted device with KernelSU or Magisk
[ ] Termux from F-Droid (NOT Play Store)
[ ] patchelf installed: pkg install patchelf

Why F-Droid?

More permissive update cycle
Full access to proot-distro
Better compatibility with custom ROMs

📖 Learn more about F-Droid

Installation Guide

Step 1: Install Debian rootfs

# Install required packages
pkg install proot-distro rsync -y

# Install Debian
proot-distro install debian

# Define paths
ROOTFS="$PREFIX/var/lib/proot-distro/installed-rootfs/debian"
GLIBC="$HOME/glibc-root"

# Install base packages
proot-distro login debian -- bash -c "
  apt-get update &&
  apt-get install -y gcc g++ make python3 bun curl unzip zip ca-certificates
"

📖 What is proot-distro? | What is rsync?

Step 2: Extract rootfs to native location

mkdir -p "$GLIBC"
rsync -a "$ROOTFS/" "$GLIBC/"

⚠️ Critical: Fix Symlinks (Click to expand)

Root-created symlinks inherit security context that blocks Termux UID access. This fix is mandatory!

#!/usr/bin/env python3
"""Fix symlinks for Termux UID compatibility"""
import os, subprocess

rootfs = os.path.expanduser("~/glibc-root")

for dirpath, dirs, files in os.walk(rootfs):
    for name in files:
        path = os.path.join(dirpath, name)
        if os.path.islink(path):
            target = None
            try:
                target = os.readlink(path)
            except:
                result = subprocess.run(
                    ["su", "-c", f"readlink {path}"],
                    capture_output=True, text=True
                )
                target = result.stdout.strip()

            if target:
                try:
                    os.unlink(path)
                except:
                    subprocess.run(["su", "-c", f"rm -f {path}"], capture_output=True)
                os.symlink(target, path)

print("✓ Symlinks repaired.")

Step 3: Fix the dynamic linker

GLIBC="$HOME/glibc-root"
LOADER="$GLIBC/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1"

mkdir -p "$GLIBC/lib64"
ln -sf "$LOADER" "$GLIBC/lib64/ld-linux-aarch64.so.1"
ln -sf "$LOADER" "$GLIBC/lib/ld-linux-aarch64.so.1"

📖 Learn about ld-linux.so

Step 4: Mass patchelf — make all binaries self-contained

GLIBC="$HOME/glibc-root"
LOADER="$GLIBC/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1"
RPATH="$GLIBC/lib/aarch64-linux-gnu:$GLIBC/usr/lib/aarch64-linux-gnu"
OUT="$PREFIX/bin"

for bin in "$GLIBC/usr/bin/"* "$GLIBC/bin/"*; do
    [[ -f "$bin" && -x "$bin" ]] || continue
    name=$(basename "$bin")-glibc
    cp "$bin" "$OUT/$name"
    patchelf --set-interpreter "$LOADER" \
             --set-rpath "$RPATH" \
             "$OUT/$name" 2>/dev/null || rm -f "$OUT/$name"
done

echo "✓ Patched $(ls $OUT/*-glibc 2>/dev/null | wc -l) binaries"

📖 What is patchelf?

Step 5: Fix ownership

su -c "chown -R $(id -u):$(id -g) $HOME/glibc-root"
su -c "find $HOME/glibc-root -type d -exec chmod 755 {} \;"

Step 6: Create the Smart APT wrapper

cat > ~/apt-debian << 'SCRIPT'
#!/data/data/com.termux/files/usr/bin/bash
# apt-debian v3 — installs from Debian and auto-patchelfs

GLIBC="$HOME/glibc-root"
LOADER="$GLIBC/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1"
RPATH="$GLIBC/lib/aarch64-linux-gnu:$GLIBC/usr/lib/aarch64-linux-gnu"

case "$1" in
  install)
    shift
    BEFORE=$(find "$GLIBC/usr/bin" "$GLIBC/bin" -maxdepth 1 -type f -executable 2>/dev/null | sort)
    su -c "cp /system/etc/resolv.conf $GLIBC/etc/resolv.conf 2>/dev/null || \
           echo 'nameserver 8.8.8.8' > $GLIBC/etc/resolv.conf"
    su -c "chroot $GLIBC /usr/bin/apt-get install -y $*"
    AFTER=$(find "$GLIBC/usr/bin" "$GLIBC/bin" -maxdepth 1 -type f -executable 2>/dev/null | sort)
    NEW=$(comm -13 <(echo "$BEFORE") <(echo "$AFTER"))

    for bin in $NEW; do
      name="$(basename $bin)-glibc"
      cp "$bin" "$PREFIX/bin/$name"
      patchelf --set-interpreter "$LOADER" --set-rpath "$RPATH" "$PREFIX/bin/$name" 2>/dev/null
      chmod +x "$PREFIX/bin/$name"
      echo "✓ $name available"
    done
    ;;
  update)
    su -c "chroot $GLIBC /usr/bin/apt-get update"
    ;;
  *)
    echo "Usage: apt-debian {install|update} [packages]"
    ;;
esac
SCRIPT

chmod +x ~/apt-debian
mv ~/apt-debian "$PREFIX/bin/apt-debian"

Step 7: Add to PATH

echo 'export PATH="$HOME/.glibc-bin:$PATH"' >> ~/.bashrc
echo 'export GLIBC_ROOT="$HOME/glibc-root"' >> ~/.bashrc
source ~/.bashrc

Testing

🧪 Verify Installation (Click to expand)

Test Command	Expected Output
`LD_PRELOAD= gcc-glibc --version`	`gcc (Debian 14.2.0-6) 14.2.0`
`bun --version`	`1.x.x`
`apt-debian install htop && htop`	Interactive process manager

Quick Tests

# Test GCC
LD_PRELOAD= gcc-glibc --version

# Test Bun
bun --version

# Test APT wrapper
apt-debian install htop && htop

Known Limitations

⚠️ Important Notes (Click to expand)

Requires Root — The su -c fallback needs KernelSU/Magisk root. Tier 1 works rootless but may fail on complex binaries.
LD_PRELOAD= Must Be Cleared — Termux injects libtermux-exec-ld-preload.so which crashes glibc. Always run with LD_PRELOAD= if not using wrappers.
Symlink Repair Is Mandatory — apt creates symlinks as root; they inherit security context that blocks Termux UID access.

Available Binaries

📦 What Works Out of the Box (Click to expand)

Binary	Package	Official Site
✅ GCC 14	`gcc-glibc`	gcc.gnu.org
✅ Python 3.13	`python3.13-glibc`	python.org
✅ Bun	`bun`	bun.sh
✅ Git	`git-glibc`	git-scm.com
✅ htop	`htop-glibc`	htop.dev

300+ Debian aarch64 packages available via apt-debian install!

Understanding ELF and Dynamic Linker

📚 Technical Background (Click to learn)

What is ELF?

ELF (Executable and Linkable Format) is the standard binary format for executables on Linux systems. It tells the OS:

How to load the program into memory
Where to find the code and data
What libraries are needed
How to execute the program

📖 Learn more about ELF

What is the Dynamic Linker?

The dynamic linker (ld-linux.so) is the first thing that executes when you run any Linux program. It:

Loads the program into memory
Finds required libraries
Resolves symbols
Prepares the program to run

📖 Dynamic linker documentation

Samsung Firmware Flashing Reference

📱 If You Need to Flash Firmware (Click to expand)

Tool Comparison

Tool	Platform	Link
Odin	Windows PC only	Wikipedia
Heimdall	Linux/macOS	GitHub / Official
Eros	Android (No PC!)	GitHub / XDA

Galaxy S10e (SM-G970F) Resources

📖 XDA Forum - Galaxy S10e ROMs, Kernels & Recoveries

Summary

Component	Technology	Reference
Terminal	Termux	GitHub
ROM	ExtremeROM Nexus	Android 15
Root	KernelSU	Exynos 9820
Distribution	Debian	glibc
Compatibility Layer	patchelf	ELF modification
Execution Method	`LD_PRELOAD=` bypass	Native execution
Device	Samsung Galaxy S10e (SM-G970F) - Exynos 9820	ARM64/AArch64

Resources & References

📱 Device & Hardware

Topic	Link
Samsung Galaxy S10e (SM-G970F) - Exynos	GSMArena
Exynos 9820 Processor	Wikipedia
AArch64/ARM64 Architecture	Wikipedia
XDA Forum - Galaxy S10e	XDA Forums

🔧 Development Tools

Tool	Official Site
Termux	termux.dev / F-Droid
patchelf	GitHub
proot-distro	GitHub
F-Droid	f-droid.org
Bun	bun.sh
GCC	gcc.gnu.org
Python	python.org
Git	git-scm.com
htop	htop.dev

📚 Linux Concepts

Topic	Link
ELF Format	Wikipedia
Seccomp	Red Hat Docs
Dynamic Linker	man7.org
rsync	rsync.samba.org

🔐 Root & ROM

Project	Link
KernelSU	kernelsu.org
Magisk	topjohnwu.github.io/Magisk
ExtremeROM Nexus	GitHub

🔧 Firmware Tools

Tool	Link
Odin	Wikipedia
Heimdall	GitHub
Eros	GitHub

Credits

❤️ Special Thanks (Click to expand)

This article was made possible with the help of several amazing tools and communities:

AI Assistants

Tool	Role	Link
Gemini (Google AI)	Used in terminal for debugging	gemini.google.com
Claude (Anthropic)	Solved complex technical challenges	claude.ai
MiniMax Agent	Formatted and corrected the article	agent.minimax.io