From: Justin Cinkelj <justin.cink...@xlab.si>
Committer: Nadav Har'El <n...@scylladb.com>
Branch: master
calloc: allow 0-sized allocation
The calloc(nmemb, size=0) failed due to division by 0 in
"std::numeric_limits<size_t>::max() / size".
Fix this by checking for 0 value before division.
Included is also a small test case for calloc.
Signed-off-by: Justin Cinkelj <justin.cink...@xlab.si>
Message-Id: <20170615061205.16074-1-justin.cink...@xlab.si>
---
diff --git a/core/mempool.cc b/core/mempool.cc
--- a/core/mempool.cc
+++ b/core/mempool.cc
@@ -1564,6 +1564,8 @@ static inline void* std_malloc(size_t size, size_t
alignment)
void* calloc(size_t nmemb, size_t size)
{
+ if (nmemb == 0 || size == 0)
+ return malloc(0);
if (nmemb > std::numeric_limits<size_t>::max() / size)
return nullptr;
auto n = nmemb * size;
diff --git a/modules/tests/Makefile b/modules/tests/Makefile
--- a/modules/tests/Makefile
+++ b/modules/tests/Makefile
@@ -86,7 +86,8 @@ tests := tst-pthread.so misc-ramdisk.so tst-vblk.so
tst-bsd-evh.so \
tst-pthread-setcancelstate.so tst-syscall.so tst-pin.so tst-run.so \
tst-ifaddrs.so tst-pthread-affinity-inherit.so tst-sem-timed-wait.so \
tst-ttyname.so tst-pthread-barrier.so tst-feexcept.so tst-math.so \
- tst-sigaltstack.so tst-fread.so tst-tcp-cork.so tst-tcp-v6.so
+ tst-sigaltstack.so tst-fread.so tst-tcp-cork.so tst-tcp-v6.so \
+ tst-calloc.so
# libstatic-thread-variable.so tst-static-thread-variable.so \
diff --git a/tests/tst-calloc.cc b/tests/tst-calloc.cc
--- a/tests/tst-calloc.cc
+++ b/tests/tst-calloc.cc
@@ -0,0 +1,67 @@
+/*
+* Copyright (C) 2017 XLAB d.o.o.
+*
+* This work is open source software, licensed under the terms of the
+* BSD license as described in the LICENSE file in the top-level directory.
+*/
+// To compile on Linux, use: g++ -g -pthread -std=c++11 tests/tst-calloc.cc
+
+#include <string.h>
+#include <iostream>
+
+// This test assures that the calloc function works as expected in the
various
+// situations it can be used at.
+void pass_if(const char *got, const char *expected, int size, const char*
msg)
+{
+ if (memcmp(expected, got, size)) {
+ std::cerr << "FAIL: " << msg << "\n";
+ std::cerr << "ERROR: got ";
+ std::cerr << got;
+ std::cerr << " but expected ";
+ std::cerr << expected;
+ std::cerr << "\n";
+ exit(1);
+ }
+ else {
+ std::cerr << "PASS: " << msg << "\n";
+ }
+}
+
+int main()
+{
+ char *buf1;
+ const char ref0[11] = "\0";
+ const char refX[11] = "XXXXXXXXXX";
+ int len1, len2;
+
+ len1 = 1;
+ len2 = 10;
+ buf1 = (char*)calloc(len1, len2);
+ pass_if(buf1, ref0, len1 * len2, "calloc(1, 10)");
+ memset(buf1, 'X', len1 * len2);
+ free(buf1);
+
+ len1 = 2;
+ len2 = 5;
+ buf1 = (char*)calloc(len1, len2);
+ pass_if(buf1, ref0, len1 * len2, "calloc(2, 5)");
+ memset(buf1, 'X', len1 * len2);
+ free(buf1);
+
+ len1 = 1;
+ len2 = 0;
+ buf1 = (char*)calloc(len1, len2);
+ pass_if(buf1, ref0, len1 * len2, "calloc(1, 0)");
+ //memset(buf1, 'X', len1 * len2);
+ free(buf1);
+
+ len1 = 0;
+ len2 = 1;
+ buf1 = (char*)calloc(len1, len2);
+ pass_if(buf1, ref0, len1 * len2, "calloc(0, 1)");
+ memset(buf1, 'X', len1 * len2);
+ free(buf1);
+
+ std::cerr << "PASSED\n";
+ return 0;
+}
--
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