aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator/beam/erl_bits.c
diff options
context:
space:
mode:
authorSverker Eriksson <[email protected]>2013-11-29 20:00:49 +0100
committerSverker Eriksson <[email protected]>2013-11-29 20:00:49 +0100
commit2bc1b1c962adf7849abb5a8399706aad708c5969 (patch)
treecc912e07da3356b1b82eabd391a2bd2eaf2635e5 /erts/emulator/beam/erl_bits.c
parent8b7faf3fecf7a8204b0d941713150adca4d20a7d (diff)
parent35b4fd5d91cbeb1b9c8540996624856134e091e9 (diff)
downloadotp-2bc1b1c962adf7849abb5a8399706aad708c5969.tar.gz
otp-2bc1b1c962adf7849abb5a8399706aad708c5969.tar.bz2
otp-2bc1b1c962adf7849abb5a8399706aad708c5969.zip
Merge branch 'sverk/bit-cmp-bug/OTP-11501' into maint
* sverk/bit-cmp-bug/OTP-11501: erts: Fix invalid read when appending binaries during call trace erts: Optimize comparison for bitstrings with byte aligned start erts: Fix invalid read in bitstring comparison
Diffstat (limited to 'erts/emulator/beam/erl_bits.c')
-rw-r--r--erts/emulator/beam/erl_bits.c111
1 files changed, 65 insertions, 46 deletions
diff --git a/erts/emulator/beam/erl_bits.c b/erts/emulator/beam/erl_bits.c
index 43eb691338..73765772c8 100644
--- a/erts/emulator/beam/erl_bits.c
+++ b/erts/emulator/beam/erl_bits.c
@@ -1,7 +1,7 @@
/*
* %CopyrightBegin%
*
- * Copyright Ericsson AB 1999-2012. All Rights Reserved.
+ * Copyright Ericsson AB 1999-2013. All Rights Reserved.
*
* The contents of this file are subject to the Erlang Public License,
* Version 1.1, (the "License"); you may not use this file except in
@@ -1491,7 +1491,7 @@ erts_bs_private_append(Process* p, Eterm bin, Eterm build_size_term, Uint unit)
bptr->flags = 0;
bptr->orig_size = new_size;
erts_refc_init(&bptr->refc, 1);
- sys_memcpy(bptr->orig_bytes, binp->orig_bytes, pb->size);
+ sys_memcpy(bptr->orig_bytes, binp->orig_bytes, binp->orig_size);
pb->flags |= PB_IS_WRITABLE | PB_ACTIVE_WRITER;
pb->val = bptr;
pb->bytes = (byte *) bptr->orig_bytes;
@@ -1810,6 +1810,11 @@ erts_cmp_bits(byte* a_ptr, size_t a_offs, byte* b_ptr, size_t b_offs, size_t siz
Uint rshift;
int cmp;
+ ASSERT(a_offs < 8 && b_offs < 8);
+
+ if (size == 0)
+ return 0;
+
if (((a_offs | b_offs | size) & 7) == 0) {
int byte_size = size >> 3;
return sys_memcmp(a_ptr, b_ptr, byte_size);
@@ -1818,58 +1823,72 @@ erts_cmp_bits(byte* a_ptr, size_t a_offs, byte* b_ptr, size_t b_offs, size_t siz
/* Compare bit by bit until a_ptr is aligned on byte boundary */
a = *a_ptr++;
b = *b_ptr++;
- while (size > 0) {
- a_bit = get_bit(a, a_offs);
- b_bit = get_bit(b, b_offs);
- if ((cmp = (a_bit-b_bit)) != 0) {
- return cmp;
- }
- size--;
- b_offs++;
- if (b_offs == 8) {
- b_offs = 0;
- b = *b_ptr++;
- }
- a_offs++;
- if (a_offs == 8) {
- a_offs = 0;
- a = *a_ptr++;
- break;
+ if (a_offs) {
+ for (;;) {
+ a_bit = get_bit(a, a_offs);
+ b_bit = get_bit(b, b_offs);
+ if ((cmp = (a_bit-b_bit)) != 0) {
+ return cmp;
+ }
+ if (--size == 0)
+ return 0;
+
+ b_offs++;
+ if (b_offs == 8) {
+ b_offs = 0;
+ b = *b_ptr++;
+ }
+ a_offs++;
+ if (a_offs == 8) {
+ a_offs = 0;
+ a = *a_ptr++;
+ break;
+ }
}
}
/* Compare byte by byte as long as at least 8 bits remain */
- lshift = b_offs;
- rshift = 8 - lshift;
- while (size >= 8) {
- byte b_cmp = (b << lshift);
- b = *b_ptr++;
- b_cmp |= b >> rshift;
- if ((cmp = (a - b_cmp)) != 0) {
- return cmp;
- }
+ if (size >= 8) {
+ lshift = b_offs;
+ rshift = 8 - lshift;
+ for (;;) {
+ byte b_cmp = (b << lshift);
+ b = *b_ptr++;
+ b_cmp |= b >> rshift;
+ if ((cmp = (a - b_cmp)) != 0) {
+ return cmp;
+ }
+ size -= 8;
+ if (size < 8)
+ break;
+ a = *a_ptr++;
+ }
+
+ if (size == 0)
+ return 0;
a = *a_ptr++;
- size -= 8;
}
/* Compare the remaining bits bit by bit */
- while (size > 0) {
- a_bit = get_bit(a, a_offs);
- b_bit = get_bit(b, b_offs);
- if ((cmp = (a_bit-b_bit)) != 0) {
- return cmp;
- }
- a_offs++;
- if (a_offs == 8) {
- a_offs = 0;
- a = *a_ptr++;
- }
- b_offs++;
- if (b_offs == 8) {
- b_offs = 0;
- b = *b_ptr++;
- }
- size--;
+ if (size > 0) {
+ for (;;) {
+ a_bit = get_bit(a, a_offs);
+ b_bit = get_bit(b, b_offs);
+ if ((cmp = (a_bit-b_bit)) != 0) {
+ return cmp;
+ }
+ if (--size == 0)
+ return 0;
+
+ a_offs++;
+ ASSERT(a_offs < 8);
+
+ b_offs++;
+ if (b_offs == 8) {
+ b_offs = 0;
+ b = *b_ptr++;
+ }
+ }
}
return 0;