asmsh/child.s

# Copyright Yann Weber <asmsh@yannweb.net>
# This file is part of asmsh.
# 
# asmsh is free software: you can redistribute it and/or modify it under the
# terms of the GNU General Public License as published by the Free Software
# Foundation, either version 3 of the License, or any later version.
# 
# asmsh is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details.
# 
# You should have received a copy of the GNU General Public License along
# with asmsh. If not, see <https://www.gnu.org/licenses/>.

.ifndef MAP_SIZE
.set MAP_LEN, 0x1000
.endif

.file "child64.s"

.comm map_len 8

.section .text
.global _start

map_exec:

_start:
	mov %rsp, %r15
	mov $MAP_LEN, %r14
	movq %r14, (map_len)
	lea redo(%rip), %rax
	push %rax # redo addr
	pushq $MAP_LEN # map size

	mov $0x9, %rax # MMAP
	xor %rdi, %rdi
	mov (%rsp), %rsi # 1 page map
	#mov $(0x1|0x2), %rdx # PROT_READ | PROT_WRITE
	mov $(0x1|0x4|0x2), %rdx # PROT_READ | PROT_EXEC | PROT_WRITE
	mov $(0x20 | 0x1), %r10 # MAP_ANONYMOUS | MAP_SHARED
	mov $-1, %r8 # fd
	xor %r9, %r9
	syscall

	push %rax
	cmp $0, %rax
	jle .errmap

	redo:
	jmp *(%rsp)


	.err:
		mov $60, %rax # sys_exit
		mov $3, %rdi
		syscall


	.errmap:
		mov $60, %rax # sys_exit
		mov $1, %rdi
		syscall


	## PAUSE SYSCALL example
	#mov $60, %rax
	#xor %rdi, %rdi
	#syscall