Use random data for benchmark instead of zeros.
If we always write zeros, we're leaving a giant pile of known
plaintext at an almost deterministic location on newly formatted
volumes. To avoid this, repeat a 64K chunk of random data.
Bug: 22816936
Change-Id: Iedc067a519bd676a93b9d74ea4f9f77c84c8461c
diff --git a/bench/benchgen.py b/bench/benchgen.py
index 077336c..77262c4 100644
--- a/bench/benchgen.py
+++ b/bench/benchgen.py
@@ -159,6 +159,8 @@
#include <algorithm>
#include <string>
+#include <Utils.h>
+
namespace android {
namespace vold {
@@ -262,35 +264,32 @@
return 0;
}
-static status_t CreateFile(const char* name, size_t len) {
- status_t res = -1;
- int in = -1;
+static status_t CreateFile(const char* name, int len) {
+ int chunk = std::min(len, 65536);
int out = -1;
+ std::string buf;
- if ((in = TEMP_FAILURE_RETRY(open("/dev/zero", O_RDONLY))) < 0) {
- PLOG(ERROR) << "Failed to open";
- goto done;
+ if (android::vold::ReadRandomBytes(chunk, buf) != OK) {
+ LOG(ERROR) << "Failed to read random data";
+ return -EIO;
}
if ((out = TEMP_FAILURE_RETRY(open(name, O_WRONLY|O_CREAT|O_TRUNC))) < 0) {
PLOG(ERROR) << "Failed to open " << name;
- goto done;
+ return -errno;
}
- char buf[65536];
while (len > 0) {
- int n = read(in, buf, std::min(len, sizeof(buf)));
- if (write(out, buf, n) != n) {
+ int n = write(out, buf.c_str(), std::min(len, chunk));
+ if (n < 0) {
PLOG(ERROR) << "Failed to write";
- goto done;
+ close(out);
+ return -errno;
}
len -= n;
}
- res = 0;
-done:
- close(in);
close(out);
- return res;
+ return OK;
}
static status_t BenchmarkCreate() {