.syntax unified
    .arm
    .section .text
    .global _start
    .type _start, %function
_start:
    ldr r3, [sp]            @ argc
    add r4, sp, #4          @ argv = &stack[1]
    add r5, r4, r3, lsl #2 @ envp = argv + argc
    add r5, r5, #4          @ skip argv terminator

    mov r0, #0
    mov r1, #0
    mov r2, #0
    mov r7, #170            @ setresgid(0, 0, 0)
    svc #0

    mov r0, #0
    mov r1, #0
    mov r2, #0
    mov r7, #164            @ setresuid(0, 0, 0)
    svc #0

    adr r0, shell_path
    mov r1, r4
    mov r2, r5
    mov r7, #11             @ execve("/system/bin/sh", argv, envp)
    svc #0

    mov r0, #127
    mov r7, #1              @ exit(127)
    svc #0

    .align 2
shell_path:
    .asciz "/system/bin/sh"
    .size _start, .-_start