1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
/* Copyright (C) 1996-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Pat Beirne <patb@corelcomputer.com>
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
/* clone() is even more special than fork() as it mucks with stacks
and invokes a function in the right context after its all over. */
#include <sysdep.h>
#include <tcb-offsets.h>
#define _ERRNO_H 1
#include <bits/errno.h>
/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
pid_t *ptid, struct user_desc *tls, pid_t *ctid); */
.text
ENTRY(__clone)
@ sanity check args
cmp r0, #0
ite ne
cmpne r1, #0
moveq r0, #-EINVAL
beq PLTJMP(syscall_error)
@ insert the args onto the new stack
str r3, [r1, #-4]!
str r0, [r1, #-4]!
@ do the system call
@ get flags
mov r0, r2
mov ip, r2
@ new sp is already in r1
push {r4, r7}
cfi_adjust_cfa_offset (8)
cfi_rel_offset (r4, 0)
cfi_rel_offset (r7, 4)
ldr r2, [sp, #8]
ldr r3, [sp, #12]
ldr r4, [sp, #16]
ldr r7, =SYS_ify(clone)
swi 0x0
cfi_endproc
cmp r0, #0
beq 1f
pop {r4, r7}
blt PLTJMP(C_SYMBOL_NAME(__syscall_error))
RETINSTR(, lr)
cfi_startproc
PSEUDO_END (__clone)
1:
.fnstart
.cantunwind
@ pick the function arg and call address off the stack and execute
ldr r0, [sp, #4]
ldr ip, [sp], #8
BLX (ip)
@ and we are done, passing the return value through r0
ldr r7, =SYS_ify(exit)
swi 0x0
.fnend
libc_hidden_def (__clone)
weak_alias (__clone, clone)
|
