| /* Copyright (C) 1996-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Richard Henderson (rth@tamu.edu) |
| |
| 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> |
| #define _ERRNO_H 1 |
| #include <bits/errno.h> |
| #include <asm-syntax.h> |
| |
| /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, |
| pid_t *ptid, struct user_desc *tls, pid_t *ctid); */ |
| |
| #define PARMS 4 /* no space for saved regs */ |
| #define FUNC PARMS |
| #define STACK FUNC+4 |
| #define FLAGS STACK+4 |
| #define ARG FLAGS+4 |
| #define PTID ARG+4 |
| #define TLS PTID+4 |
| #define CTID TLS+4 |
| |
| #define __NR_clone 120 |
| #define SYS_clone 120 |
| |
| .text |
| ENTRY (__clone) |
| /* Sanity check arguments. */ |
| movl $-EINVAL,%eax |
| movl FUNC(%esp),%ecx /* no NULL function pointers */ |
| testl %ecx,%ecx |
| jz SYSCALL_ERROR_LABEL |
| movl STACK(%esp),%ecx /* no NULL stack pointers */ |
| testl %ecx,%ecx |
| jz SYSCALL_ERROR_LABEL |
| |
| /* Insert the argument onto the new stack. Make sure the new |
| thread is started with an alignment of (mod 16). */ |
| andl $0xfffffff0, %ecx |
| subl $28,%ecx |
| movl ARG(%esp),%eax /* no negative argument counts */ |
| movl %eax,12(%ecx) |
| |
| /* Save the function pointer as the zeroth argument. |
| It will be popped off in the child in the ebx frobbing below. */ |
| movl FUNC(%esp),%eax |
| movl %eax,8(%ecx) |
| /* Don't leak any information. */ |
| movl $0,4(%ecx) |
| |
| /* Do the system call */ |
| pushl %ebx |
| cfi_adjust_cfa_offset (4) |
| pushl %esi |
| cfi_adjust_cfa_offset (4) |
| pushl %edi |
| cfi_adjust_cfa_offset (4) |
| |
| movl TLS+12(%esp),%esi |
| cfi_rel_offset (esi, 4) |
| movl PTID+12(%esp),%edx |
| movl FLAGS+12(%esp),%ebx |
| cfi_rel_offset (ebx, 8) |
| movl CTID+12(%esp),%edi |
| cfi_rel_offset (edi, 0) |
| movl $SYS_ify(clone),%eax |
| |
| /* Remember the flag value. */ |
| movl %ebx, (%ecx) |
| |
| /* End FDE now, because in the child the unwind info will be |
| wrong. */ |
| cfi_endproc |
| |
| int $0x80 |
| popl %edi |
| popl %esi |
| popl %ebx |
| |
| test %eax,%eax |
| jl SYSCALL_ERROR_LABEL |
| jz L(thread_start) |
| |
| ret |
| |
| L(thread_start): |
| cfi_startproc; |
| /* Clearing frame pointer is insufficient, use CFI. */ |
| cfi_undefined (eip); |
| /* Note: %esi is zero. */ |
| movl %esi,%ebp /* terminate the stack frame */ |
| call *%ebx |
| #ifdef PIC |
| call L(here) |
| L(here): |
| popl %ebx |
| addl $_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebx |
| #endif |
| movl %eax, %ebx |
| movl $SYS_ify(exit), %eax |
| ENTER_KERNEL |
| |
| PSEUDO_END (__clone) |
| |
| libc_hidden_def (__clone) |
| weak_alias (__clone, clone) |