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/*
* Copyright (C) 2013 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <private/bionic_asm.h>
#include <private/libc_events.h>
.syntax unified
.thumb
.thumb_func
// Get the length of src string, then get the source of the dst string.
// Check that the two lengths together don't exceed the threshold, then
// do a memcpy of the data.
ENTRY(__strcat_chk)
pld [r0, #0]
push {r0, lr}
.save {r0, lr}
.cfi_def_cfa_offset 8
.cfi_rel_offset r0, 0
.cfi_rel_offset lr, 4
push {r4, r5}
.save {r4, r5}
.cfi_adjust_cfa_offset 8
.cfi_rel_offset r4, 0
.cfi_rel_offset r5, 4
mov lr, r2
// Save the dst register to r5
mov r5, r0
// Zero out r4
eor r4, r4, r4
// r1 contains the address of the string to count.
.L_strlen_start:
mov r0, r1
ands r3, r1, #7
beq .L_mainloop
// Align to a double word (64 bits).
rsb r3, r3, #8
lsls ip, r3, #31
beq .L_align_to_32
ldrb r2, [r1], #1
cbz r2, .L_update_count_and_finish
.L_align_to_32:
bcc .L_align_to_64
ands ip, r3, #2
beq .L_align_to_64
ldrb r2, [r1], #1
cbz r2, .L_update_count_and_finish
ldrb r2, [r1], #1
cbz r2, .L_update_count_and_finish
.L_align_to_64:
tst r3, #4
beq .L_mainloop
ldr r3, [r1], #4
sub ip, r3, #0x01010101
bic ip, ip, r3
ands ip, ip, #0x80808080
bne .L_zero_in_second_register
.p2align 2
.L_mainloop:
ldrd r2, r3, [r1], #8
pld [r1, #64]
sub ip, r2, #0x01010101
bic ip, ip, r2
ands ip, ip, #0x80808080
bne .L_zero_in_first_register
sub ip, r3, #0x01010101
bic ip, ip, r3
ands ip, ip, #0x80808080
bne .L_zero_in_second_register
b .L_mainloop
.L_update_count_and_finish:
sub r3, r1, r0
sub r3, r3, #1
b .L_finish
.L_zero_in_first_register:
sub r3, r1, r0
lsls r2, ip, #17
bne .L_sub8_and_finish
bcs .L_sub7_and_finish
lsls ip, ip, #1
bne .L_sub6_and_finish
sub r3, r3, #5
b .L_finish
.L_sub8_and_finish:
sub r3, r3, #8
b .L_finish
.L_sub7_and_finish:
sub r3, r3, #7
b .L_finish
.L_sub6_and_finish:
sub r3, r3, #6
b .L_finish
.L_zero_in_second_register:
sub r3, r1, r0
lsls r2, ip, #17
bne .L_sub4_and_finish
bcs .L_sub3_and_finish
lsls ip, ip, #1
bne .L_sub2_and_finish
sub r3, r3, #1
b .L_finish
.L_sub4_and_finish:
sub r3, r3, #4
b .L_finish
.L_sub3_and_finish:
sub r3, r3, #3
b .L_finish
.L_sub2_and_finish:
sub r3, r3, #2
.L_finish:
cmp r4, #0
bne .L_strlen_done
// Time to get the dst string length.
mov r1, r5
// Save the original source address to r5.
mov r5, r0
// Save the current length (adding 1 for the terminator).
add r4, r3, #1
b .L_strlen_start
// r0 holds the pointer to the dst string.
// r3 holds the dst string length.
// r4 holds the src string length + 1.
.L_strlen_done:
add r2, r3, r4
cmp r2, lr
bhi __strcat_chk_failed
// Set up the registers for the memcpy code.
mov r1, r5
pld [r1, #64]
mov r2, r4
add r0, r0, r3
pop {r4, r5}
END(__strcat_chk)
#define MEMCPY_BASE __strcat_chk_memcpy_base
#define MEMCPY_BASE_ALIGNED __strcat_chk_memcpy_base_aligned
#include "memcpy_base.S"
ENTRY_PRIVATE(__strcat_chk_failed)
.save {r0, lr}
.save {r4, r5}
.cfi_def_cfa_offset 8
.cfi_rel_offset r0, 0
.cfi_rel_offset lr, 4
.cfi_adjust_cfa_offset 8
.cfi_rel_offset r4, 0
.cfi_rel_offset r5, 4
ldr r0, error_message
ldr r1, error_code
1:
add r0, pc
bl __fortify_chk_fail
error_code:
.word BIONIC_EVENT_STRCAT_BUFFER_OVERFLOW
error_message:
.word error_string-(1b+4)
END(__strcat_chk_failed)
.data
error_string:
.string "strcat: prevented write past end of buffer"
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