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dff8da6b | 1 | /* Copyright (C) 1996-2024 Free Software Foundation, Inc. |
0c5ecdc4 | 2 | This file is part of the GNU C Library. |
267ca16a | 3 | |
0c5ecdc4 | 4 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
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. | |
267ca16a | 8 | |
0c5ecdc4 UD |
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 | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
267ca16a | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
267ca16a UD |
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> | |
11336c16 | 22 | #define _ERRNO_H 1 |
5107cf1d | 23 | #include <bits/errno.h> |
cbdee279 | 24 | #include <asm-syntax.h> |
267ca16a | 25 | |
b7cb624b | 26 | /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, |
b33e6163 | 27 | pid_t *ptid, struct user_desc *tls, pid_t *ctid); */ |
267ca16a | 28 | |
2366713d | 29 | #define PARMS 4 /* no space for saved regs */ |
9e25f6e2 GM |
30 | #define FUNC PARMS |
31 | #define STACK FUNC+4 | |
2366713d | 32 | #define FLAGS STACK+4 |
9e25f6e2 | 33 | #define ARG FLAGS+4 |
2366713d JM |
34 | #define PTID ARG+4 |
35 | #define TLS PTID+4 | |
36 | #define CTID TLS+4 | |
b7cb624b UD |
37 | |
38 | #define __NR_clone 120 | |
39 | #define SYS_clone 120 | |
9e25f6e2 | 40 | |
267ca16a | 41 | .text |
2366713d | 42 | ENTRY (__clone) |
267ca16a UD |
43 | /* Sanity check arguments. */ |
44 | movl $-EINVAL,%eax | |
9e25f6e2 | 45 | movl FUNC(%esp),%ecx /* no NULL function pointers */ |
69963deb UD |
46 | testl %ecx,%ecx |
47 | jz SYSCALL_ERROR_LABEL | |
9e25f6e2 | 48 | movl STACK(%esp),%ecx /* no NULL stack pointers */ |
69963deb UD |
49 | testl %ecx,%ecx |
50 | jz SYSCALL_ERROR_LABEL | |
267ca16a | 51 | |
6c052003 UD |
52 | /* Insert the argument onto the new stack. Make sure the new |
53 | thread is started with an alignment of (mod 16). */ | |
54 | andl $0xfffffff0, %ecx | |
7d585303 | 55 | subl $28,%ecx |
9e25f6e2 | 56 | movl ARG(%esp),%eax /* no negative argument counts */ |
56c91066 | 57 | movl %eax,12(%ecx) |
0c5ecdc4 | 58 | |
267ca16a UD |
59 | /* Save the function pointer as the zeroth argument. |
60 | It will be popped off in the child in the ebx frobbing below. */ | |
9e25f6e2 | 61 | movl FUNC(%esp),%eax |
56c91066 | 62 | movl %eax,8(%ecx) |
dde36a31 | 63 | /* Don't leak any information. */ |
56c91066 | 64 | movl $0,4(%ecx) |
267ca16a UD |
65 | |
66 | /* Do the system call */ | |
67 | pushl %ebx | |
1ad9da69 | 68 | cfi_adjust_cfa_offset (4) |
b7cb624b | 69 | pushl %esi |
1ad9da69 | 70 | cfi_adjust_cfa_offset (4) |
56c91066 | 71 | pushl %edi |
1ad9da69 | 72 | cfi_adjust_cfa_offset (4) |
fee732e5 | 73 | |
56c91066 | 74 | movl TLS+12(%esp),%esi |
1ad9da69 | 75 | cfi_rel_offset (esi, 4) |
56c91066 UD |
76 | movl PTID+12(%esp),%edx |
77 | movl FLAGS+12(%esp),%ebx | |
1ad9da69 | 78 | cfi_rel_offset (ebx, 8) |
56c91066 | 79 | movl CTID+12(%esp),%edi |
1ad9da69 | 80 | cfi_rel_offset (edi, 0) |
267ca16a | 81 | movl $SYS_ify(clone),%eax |
1ff241b8 | 82 | |
1ff241b8 UD |
83 | /* Remember the flag value. */ |
84 | movl %ebx, (%ecx) | |
1ff241b8 | 85 | |
fee732e5 UD |
86 | /* End FDE now, because in the child the unwind info will be |
87 | wrong. */ | |
88 | cfi_endproc | |
89 | ||
267ca16a | 90 | int $0x80 |
56c91066 | 91 | popl %edi |
b7cb624b | 92 | popl %esi |
267ca16a UD |
93 | popl %ebx |
94 | ||
95 | test %eax,%eax | |
c0fb8a56 | 96 | jl SYSCALL_ERROR_LABEL |
b7cb624b | 97 | jz L(thread_start) |
267ca16a UD |
98 | |
99 | ret | |
267ca16a | 100 | |
b7cb624b | 101 | L(thread_start): |
11bf311e UD |
102 | cfi_startproc; |
103 | /* Clearing frame pointer is insufficient, use CFI. */ | |
104 | cfi_undefined (eip); | |
1ff241b8 UD |
105 | /* Note: %esi is zero. */ |
106 | movl %esi,%ebp /* terminate the stack frame */ | |
267ca16a | 107 | call *%ebx |
b7cb624b UD |
108 | movl %eax, %ebx |
109 | movl $SYS_ify(exit), %eax | |
1ad9da69 | 110 | ENTER_KERNEL |
267ca16a | 111 | |
2366713d | 112 | PSEUDO_END (__clone) |
6ed0492f | 113 | |
9ff72da4 | 114 | libc_hidden_def (__clone) |
2366713d | 115 | weak_alias (__clone, clone) |