1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29#include <platform/bionic/tls_defines.h> 30#include <private/bionic_asm.h> 31 32// This custom code preserves the return address across the system call. 33 34ENTRY_WEAK_FOR_NATIVE_BRIDGE(vfork) 35 popl %ecx // Grab the return address. 36 .cfi_adjust_cfa_offset 4 37 .cfi_rel_offset ecx, 0 38 39 // Set cached_pid_ to 0, vforked_ to 1, and stash the previous value. 40 movl %gs:0, %eax 41 movl (TLS_SLOT_THREAD_ID * 4)(%eax), %eax 42 movl 12(%eax), %edx 43 movl $0x80000000, 12(%eax) 44 45 movl $__NR_vfork, %eax 46 int $0x80 47 48 test %eax, %eax 49 jz 1f 50 51 // rc != 0: restore the previous cached_pid_/vforked_ values. 52 pushl %ecx 53 movl %gs:0, %ecx 54 movl (TLS_SLOT_THREAD_ID * 4)(%ecx), %ecx 55 movl %edx, 12(%ecx) 56 popl %ecx 57 58 cmpl $-MAX_ERRNO, %eax 59 jb 1f 60 negl %eax 61 pushl %eax 62 call __set_errno_internal 631: 64 jmp *%ecx // Jump to the stored return address. 65END(vfork) 66