| 1 | /* Copyright (C) 1996-2022 Free Software Foundation, Inc. |
|---|
| 2 | This file is part of the GNU C Library. |
|---|
| 3 | |
|---|
| 4 | The GNU C Library is free software; you can redistribute it and/or |
|---|
| 5 | modify it under the terms of the GNU Lesser General Public |
|---|
| 6 | License as published by the Free Software Foundation; either |
|---|
| 7 | version 2.1 of the License, or (at your option) any later version. |
|---|
| 8 | |
|---|
| 9 | The GNU C Library is distributed in the hope that it will be useful, |
|---|
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
|---|
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
|---|
| 12 | Lesser General Public License for more details. |
|---|
| 13 | |
|---|
| 14 | You should have received a copy of the GNU Lesser General Public |
|---|
| 15 | License along with the GNU C Library. If not, see |
|---|
| 16 | <https://www.gnu.org/licenses/>. */ |
|---|
| 17 | |
|---|
| 18 | /* clone() is even more special than fork() as it mucks with stacks |
|---|
| 19 | and invokes a function in the right context after its all over. */ |
|---|
| 20 | |
|---|
| 21 | #include <sysdep.h> |
|---|
| 22 | #include <tcb-offsets.h> |
|---|
| 23 | #define _ERRNO_H 1 |
|---|
| 24 | #include <bits/errno.h> |
|---|
| 25 | |
|---|
| 26 | /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, |
|---|
| 27 | pid_t *ptid, struct user_desc *tls, pid_t *ctid); */ |
|---|
| 28 | |
|---|
| 29 | .text |
|---|
| 30 | ENTRY(__clone) |
|---|
| 31 | @ sanity check args |
|---|
| 32 | cmp r0, #0 |
|---|
| 33 | @ align sp |
|---|
| 34 | and r1, r1, #-8 |
|---|
| 35 | ite ne |
|---|
| 36 | cmpne r1, #0 |
|---|
| 37 | moveq r0, #-EINVAL |
|---|
| 38 | beq PLTJMP(syscall_error) |
|---|
| 39 | |
|---|
| 40 | @ insert the args onto the new stack |
|---|
| 41 | str r3, [r1, #-4]! |
|---|
| 42 | str r0, [r1, #-4]! |
|---|
| 43 | |
|---|
| 44 | @ do the system call |
|---|
| 45 | @ get flags |
|---|
| 46 | mov r0, r2 |
|---|
| 47 | mov ip, r2 |
|---|
| 48 | @ new sp is already in r1 |
|---|
| 49 | push {r4, r7} |
|---|
| 50 | cfi_adjust_cfa_offset (8) |
|---|
| 51 | cfi_rel_offset (r4, 0) |
|---|
| 52 | cfi_rel_offset (r7, 4) |
|---|
| 53 | ldr r2, [sp, #8] |
|---|
| 54 | ldr r3, [sp, #12] |
|---|
| 55 | ldr r4, [sp, #16] |
|---|
| 56 | ldr r7, =SYS_ify(clone) |
|---|
| 57 | swi 0x0 |
|---|
| 58 | cfi_endproc |
|---|
| 59 | cmp r0, #0 |
|---|
| 60 | beq 1f |
|---|
| 61 | pop {r4, r7} |
|---|
| 62 | blt PLTJMP(C_SYMBOL_NAME(__syscall_error)) |
|---|
| 63 | RETINSTR(, lr) |
|---|
| 64 | |
|---|
| 65 | cfi_startproc |
|---|
| 66 | PSEUDO_END (__clone) |
|---|
| 67 | |
|---|
| 68 | 1: |
|---|
| 69 | .fnstart |
|---|
| 70 | .cantunwind |
|---|
| 71 | @ pick the function arg and call address off the stack and execute |
|---|
| 72 | ldr r0, [sp, #4] |
|---|
| 73 | ldr ip, [sp], #8 |
|---|
| 74 | BLX (ip) |
|---|
| 75 | |
|---|
| 76 | @ and we are done, passing the return value through r0 |
|---|
| 77 | ldr r7, =SYS_ify(exit) |
|---|
| 78 | swi 0x0 |
|---|
| 79 | |
|---|
| 80 | .fnend |
|---|
| 81 | |
|---|
| 82 | libc_hidden_def (__clone) |
|---|
| 83 | weak_alias (__clone, clone) |
|---|
| 84 | |
|---|
