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/**
* Copyright (C) ARM Limited 2014-2015. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include "FtraceDriver.h"
#include <regex.h>
#include <unistd.h>
#include "DriverSource.h"
#include "Logging.h"
#include "Setup.h"
class FtraceCounter : public DriverCounter {
public:
FtraceCounter(DriverCounter *next, char *name, const char *regex, const char *enable);
~FtraceCounter();
void prepare();
int read(const char *const line, int64_t *values);
void stop();
private:
regex_t mReg;
char *const mEnable;
int mWasEnabled;
// Intentionally unimplemented
FtraceCounter(const FtraceCounter &);
FtraceCounter &operator=(const FtraceCounter &);
};
FtraceCounter::FtraceCounter(DriverCounter *next, char *name, const char *regex, const char *enable) : DriverCounter(next, name), mEnable(enable == NULL ? NULL : strdup(enable)) {
int result = regcomp(&mReg, regex, REG_EXTENDED);
if (result != 0) {
char buf[128];
regerror(result, &mReg, buf, sizeof(buf));
logg->logError("Invalid regex '%s': %s", regex, buf);
handleException();
}
}
FtraceCounter::~FtraceCounter() {
regfree(&mReg);
if (mEnable != NULL) {
free(mEnable);
}
}
void FtraceCounter::prepare() {
if (mEnable == NULL) {
return;
}
char buf[1<<10];
snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%s/enable", mEnable);
if ((DriverSource::readIntDriver(buf, &mWasEnabled) != 0) ||
(DriverSource::writeDriver(buf, 1) != 0)) {
logg->logError("Unable to read or write to %s", buf);
handleException();
}
}
int FtraceCounter::read(const char *const line, int64_t *values) {
regmatch_t match[2];
int result = regexec(&mReg, line, 2, match, 0);
if (result != 0) {
// No match
return 0;
}
int64_t value;
if (match[1].rm_so < 0) {
value = 1;
} else {
errno = 0;
value = strtoll(line + match[1].rm_so, NULL, 0);
if (errno != 0) {
logg->logError("Parsing %s failed: %s", getName(), strerror(errno));
handleException();
}
}
values[0] = getKey();
values[1] = value;
return 1;
}
void FtraceCounter::stop() {
if (mEnable == NULL) {
return;
}
char buf[1<<10];
snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%s/enable", mEnable);
DriverSource::writeDriver(buf, mWasEnabled);
}
FtraceDriver::FtraceDriver() : mValues(NULL) {
}
FtraceDriver::~FtraceDriver() {
delete [] mValues;
}
void FtraceDriver::readEvents(mxml_node_t *const xml) {
// Check the kernel version
int release[3];
if (!getLinuxVersion(release)) {
logg->logError("getLinuxVersion failed");
handleException();
}
// The perf clock was added in 3.10
if (KERNEL_VERSION(release[0], release[1], release[2]) < KERNEL_VERSION(3, 10, 0)) {
logg->logMessage("Unsupported kernel version, to use ftrace please upgrade to Linux 3.10 or later");
return;
}
mxml_node_t *node = xml;
int count = 0;
while (true) {
node = mxmlFindElement(node, xml, "event", NULL, NULL, MXML_DESCEND);
if (node == NULL) {
break;
}
const char *counter = mxmlElementGetAttr(node, "counter");
if (counter == NULL) {
continue;
}
if (strncmp(counter, "ftrace_", 7) != 0) {
continue;
}
const char *regex = mxmlElementGetAttr(node, "regex");
if (regex == NULL) {
logg->logError("The regex counter %s is missing the required regex attribute", counter);
handleException();
}
bool addCounter = true;
const char *enable = mxmlElementGetAttr(node, "enable");
if (enable != NULL) {
char buf[1<<10];
snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%s/enable", enable);
if (access(buf, W_OK) != 0) {
logg->logMessage("Disabling counter %s, %s not found", counter, buf);
addCounter = false;
}
}
if (addCounter) {
setCounters(new FtraceCounter(getCounters(), strdup(counter), regex, enable));
++count;
}
}
mValues = new int64_t[2*count];
}
void FtraceDriver::prepare() {
for (FtraceCounter *counter = static_cast<FtraceCounter *>(getCounters()); counter != NULL; counter = static_cast<FtraceCounter *>(counter->getNext())) {
if (!counter->isEnabled()) {
continue;
}
counter->prepare();
}
}
int FtraceDriver::read(const char *line, int64_t **buf) {
int count = 0;
for (FtraceCounter *counter = static_cast<FtraceCounter *>(getCounters()); counter != NULL; counter = static_cast<FtraceCounter *>(counter->getNext())) {
if (!counter->isEnabled()) {
continue;
}
count += counter->read(line, mValues + 2*count);
}
*buf = mValues;
return count;
}
void FtraceDriver::stop() {
for (FtraceCounter *counter = static_cast<FtraceCounter *>(getCounters()); counter != NULL; counter = static_cast<FtraceCounter *>(counter->getNext())) {
if (!counter->isEnabled()) {
continue;
}
counter->stop();
}
}
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