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android_system_core/logd/LogStatistics.cpp
Mark Salyzyn 807e40ecc9 liblog: logd: Add android_lookupEventTag_len() 
Allows us to mitigate the impact of MAP_PRIVATE and copy on write by
calling android_lookupEventTag_len instead of android_lookupEventTag,
and delaying the copy on write impact to the later.  We return a
string length in a supplied location along with the string pointer
with android_lookupEventTag_len(const EventTagMap* map, size_t* len,
int tag).  The string is not guaranteed to be nul terminated.  Since
android_lookupEventTag() called even once can cause the memory
impact, we will mark it as deprecated, but we currently have no
timeframe for removal since this is a very old interface.

Add an API for __android_log_is_loggable_len() that accepts the non
null terminated content and fixup callers that would gain because the
length is known prior to the call either in the compiler or at
runtime.  Tackle transition to android_lookupEventTag_len() and
fixup callers.

On any application that performs logging (eg: com.android.phone)

/proc/<pid>/smaps before:

xxxxxxxxxx-xxxxxxxxxx rw-p 00000000 fd:00 463 /system/etc/event-log-tags
Size:                 20 kB
Rss:                  20 kB
Pss:                   1 kB
Shared_Clean:          0 kB
Shared_Dirty:         20 kB
Private_Clean:         0 kB
Private_Dirty:         0 kB
Referenced:            0 kB
Anonymous:            20 kB
AnonHugePages:         0 kB
Swap:                  0 kB
SwapPss:               0 kB
KernelPageSize:        4 kB
MMUPageSize:           4 kB
Locked:                0 kB
VmFlags: rd wr mr mw me ac

/proc/<pid>/smaps after:

xxxxxxxxxx-xxxxxxxxxx rw-p 00000000 fd:00 1773 /system/etc/event-log-tags
Size:                 20 kB
Rss:                  20 kB
Pss:                   1 kB
Shared_Clean:         20 kB  (was 0kB)
Shared_Dirty:          0 kB  (was 20kB)
Private_Clean:         0 kB
Private_Dirty:         0 kB
Referenced:           20 kB  (was 0kB)
Anonymous:             0 kB  (was 20kB)
AnonHugePages:         0 kB
Swap:                  0 kB
SwapPss:               0 kB
KernelPageSize:        4 kB
MMUPageSize:           4 kB
Locked:                0 kB
VmFlags: rd wr mr mw me ac

Added liblog-unit-tests --gtest_filter=liblog.event_log_tags to
check for Shared_Clean: to not be 0 and Anonymous: to be 0 for
all processes referencing event-log-tags.  Which can include multiple
references to /system/etc/event-log-tags and future possible refs to
/data/misc/logd/event-log-tags and /dev/event-log-tags.  We want
failure messages to help point to errant code using the deprecated
interface.

This change saves 1/4MB of memory or more on a typical system.

Test: gTest liblog-unit-tests
Bug: 31456426
Change-Id: I9e08e44d9092bd96fe704b5709242e7195281d33
2016-10-03 11:08:34 -07:00

604 lines
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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <fcntl.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <log/logger.h>
#include "LogStatistics.h"
LogStatistics::LogStatistics() : enable(false) {
log_id_for_each(id) {
mSizes[id] = 0;
mElements[id] = 0;
mDroppedElements[id] = 0;
mSizesTotal[id] = 0;
mElementsTotal[id] = 0;
}
}
namespace android {
// caller must own and free character string
char *pidToName(pid_t pid) {
char *retval = NULL;
if (pid == 0) { // special case from auditd/klogd for kernel
retval = strdup("logd");
} else {
char buffer[512];
snprintf(buffer, sizeof(buffer), "/proc/%u/cmdline", pid);
int fd = open(buffer, O_RDONLY);
if (fd >= 0) {
ssize_t ret = read(fd, buffer, sizeof(buffer));
if (ret > 0) {
buffer[sizeof(buffer)-1] = '\0';
// frameworks intermediate state
if (fast<strcmp>(buffer, "<pre-initialized>")) {
retval = strdup(buffer);
}
}
close(fd);
}
}
return retval;
}
}
void LogStatistics::add(LogBufferElement *element) {
log_id_t log_id = element->getLogId();
unsigned short size = element->getMsgLen();
mSizes[log_id] += size;
++mElements[log_id];
mSizesTotal[log_id] += size;
++mElementsTotal[log_id];
if (log_id == LOG_ID_KERNEL) {
return;
}
uidTable[log_id].add(element->getUid(), element);
if (element->getUid() == AID_SYSTEM) {
pidSystemTable[log_id].add(element->getPid(), element);
}
if (!enable) {
return;
}
pidTable.add(element->getPid(), element);
tidTable.add(element->getTid(), element);
uint32_t tag = element->getTag();
if (tag) {
if (log_id == LOG_ID_SECURITY) {
securityTagTable.add(tag, element);
} else {
tagTable.add(tag, element);
}
}
}
void LogStatistics::subtract(LogBufferElement *element) {
log_id_t log_id = element->getLogId();
unsigned short size = element->getMsgLen();
mSizes[log_id] -= size;
--mElements[log_id];
if (element->getDropped()) {
--mDroppedElements[log_id];
}
if (log_id == LOG_ID_KERNEL) {
return;
}
uidTable[log_id].subtract(element->getUid(), element);
if (element->getUid() == AID_SYSTEM) {
pidSystemTable[log_id].subtract(element->getPid(), element);
}
if (!enable) {
return;
}
pidTable.subtract(element->getPid(), element);
tidTable.subtract(element->getTid(), element);
uint32_t tag = element->getTag();
if (tag) {
if (log_id == LOG_ID_SECURITY) {
securityTagTable.subtract(tag, element);
} else {
tagTable.subtract(tag, element);
}
}
}
// Atomically set an entry to drop
// entry->setDropped(1) must follow this call, caller should do this explicitly.
void LogStatistics::drop(LogBufferElement *element) {
log_id_t log_id = element->getLogId();
unsigned short size = element->getMsgLen();
mSizes[log_id] -= size;
++mDroppedElements[log_id];
uidTable[log_id].drop(element->getUid(), element);
if (element->getUid() == AID_SYSTEM) {
pidSystemTable[log_id].drop(element->getPid(), element);
}
if (!enable) {
return;
}
pidTable.drop(element->getPid(), element);
tidTable.drop(element->getTid(), element);
uint32_t tag = element->getTag();
if (tag) {
if (log_id == LOG_ID_SECURITY) {
securityTagTable.drop(tag, element);
} else {
tagTable.drop(tag, element);
}
}
}
// caller must own and free character string
const char *LogStatistics::uidToName(uid_t uid) const {
// Local hard coded favourites
if (uid == AID_LOGD) {
return strdup("auditd");
}
// Android system
if (uid < AID_APP) {
// in bionic, thread safe as long as we copy the results
struct passwd *pwd = getpwuid(uid);
if (pwd) {
return strdup(pwd->pw_name);
}
}
// Parse /data/system/packages.list
uid_t userId = uid % AID_USER;
const char *name = android::uidToName(userId);
if (!name && (userId > (AID_SHARED_GID_START - AID_APP))) {
name = android::uidToName(userId - (AID_SHARED_GID_START - AID_APP));
}
if (name) {
return name;
}
// Android application
if (uid >= AID_APP) {
struct passwd *pwd = getpwuid(uid);
if (pwd) {
return strdup(pwd->pw_name);
}
}
// report uid -> pid(s) -> pidToName if unique
for(pidTable_t::const_iterator it = pidTable.begin(); it != pidTable.end(); ++it) {
const PidEntry &entry = it->second;
if (entry.getUid() == uid) {
const char *nameTmp = entry.getName();
if (nameTmp) {
if (!name) {
name = strdup(nameTmp);
} else if (fast<strcmp>(name, nameTmp)) {
free(const_cast<char *>(name));
name = NULL;
break;
}
}
}
}
// No one
return name;
}
std::string UidEntry::formatHeader(const std::string &name, log_id_t id) const {
bool isprune = worstUidEnabledForLogid(id);
return formatLine(android::base::StringPrintf(
name.c_str(), android_log_id_to_name(id)),
std::string("Size"),
std::string(isprune ? "+/- Pruned" : ""))
+ formatLine(std::string("UID PACKAGE"),
std::string("BYTES"),
std::string(isprune ? "NUM" : ""));
}
std::string UidEntry::format(const LogStatistics &stat, log_id_t id) const {
uid_t uid = getUid();
std::string name = android::base::StringPrintf("%u", uid);
const char *nameTmp = stat.uidToName(uid);
if (nameTmp) {
name += android::base::StringPrintf(
"%*s%s", (int)std::max(6 - name.length(), (size_t)1),
"", nameTmp);
free(const_cast<char *>(nameTmp));
}
std::string size = android::base::StringPrintf("%zu", getSizes());
std::string pruned = "";
if (worstUidEnabledForLogid(id)) {
size_t totalDropped = 0;
for (LogStatistics::uidTable_t::const_iterator it = stat.uidTable[id].begin();
it != stat.uidTable[id].end(); ++it) {
totalDropped += it->second.getDropped();
}
size_t sizes = stat.sizes(id);
size_t totalSize = stat.sizesTotal(id);
size_t totalElements = stat.elementsTotal(id);
float totalVirtualSize = (float)sizes + (float)totalDropped * totalSize
/ totalElements;
size_t entrySize = getSizes();
float virtualEntrySize = entrySize;
int realPermille = virtualEntrySize * 1000.0 / sizes;
size_t dropped = getDropped();
if (dropped) {
pruned = android::base::StringPrintf("%zu", dropped);
virtualEntrySize += (float)dropped * totalSize / totalElements;
}
int virtualPermille = virtualEntrySize * 1000.0 / totalVirtualSize;
int permille = (realPermille - virtualPermille) * 1000L
/ (virtualPermille ?: 1);
if ((permille < -1) || (1 < permille)) {
std::string change;
const char *units = "%";
const char *prefix = (permille > 0) ? "+" : "";
if (permille > 999) {
permille = (permille + 1000) / 100; // Now tenths fold
units = "X";
prefix = "";
}
if ((-99 < permille) && (permille < 99)) {
change = android::base::StringPrintf("%s%d.%u%s",
prefix,
permille / 10,
((permille < 0) ? (-permille % 10) : (permille % 10)),
units);
} else {
change = android::base::StringPrintf("%s%d%s",
prefix,
(permille + 5) / 10, units);
}
ssize_t spaces = EntryBaseConstants::pruned_len
- 2 - pruned.length() - change.length();
if ((spaces <= 0) && pruned.length()) {
spaces = 1;
}
if ((spaces > 0) && (pruned.length() != 0)) {
change += android::base::StringPrintf("%*s", (int)spaces, "");
}
pruned = change + pruned;
}
}
std::string output = formatLine(name, size, pruned);
if (uid != AID_SYSTEM) {
return output;
}
static const size_t maximum_sorted_entries = 32;
std::unique_ptr<const PidEntry *[]> sorted
= stat.pidSystemTable[id].sort(uid, (pid_t)0, maximum_sorted_entries);
if (!sorted.get()) {
return output;
}
std::string byPid;
size_t index;
bool hasDropped = false;
for (index = 0; index < maximum_sorted_entries; ++index) {
const PidEntry *entry = sorted[index];
if (!entry) {
break;
}
if (entry->getSizes() <= (getSizes() / 100)) {
break;
}
if (entry->getDropped()) {
hasDropped = true;
}
byPid += entry->format(stat, id);
}
if (index > 1) { // print this only if interesting
std::string ditto("\" ");
output += formatLine(std::string(" PID/UID COMMAND LINE"),
ditto, hasDropped ? ditto : std::string(""));
output += byPid;
}
return output;
}
std::string PidEntry::formatHeader(const std::string &name, log_id_t /* id */) const {
return formatLine(name,
std::string("Size"),
std::string("Pruned"))
+ formatLine(std::string(" PID/UID COMMAND LINE"),
std::string("BYTES"),
std::string("NUM"));
}
std::string PidEntry::format(const LogStatistics &stat, log_id_t /* id */) const {
uid_t uid = getUid();
pid_t pid = getPid();
std::string name = android::base::StringPrintf("%5u/%u", pid, uid);
const char *nameTmp = getName();
if (nameTmp) {
name += android::base::StringPrintf(
"%*s%s", (int)std::max(12 - name.length(), (size_t)1),
"", nameTmp);
} else if ((nameTmp = stat.uidToName(uid))) {
name += android::base::StringPrintf(
"%*s%s", (int)std::max(12 - name.length(), (size_t)1),
"", nameTmp);
free(const_cast<char *>(nameTmp));
}
std::string size = android::base::StringPrintf("%zu",
getSizes());
std::string pruned = "";
size_t dropped = getDropped();
if (dropped) {
pruned = android::base::StringPrintf("%zu", dropped);
}
return formatLine(name, size, pruned);
}
std::string TidEntry::formatHeader(const std::string &name, log_id_t /* id */) const {
return formatLine(name,
std::string("Size"),
std::string("Pruned"))
+ formatLine(std::string(" TID/UID COMM"),
std::string("BYTES"),
std::string("NUM"));
}
std::string TidEntry::format(const LogStatistics &stat, log_id_t /* id */) const {
uid_t uid = getUid();
std::string name = android::base::StringPrintf("%5u/%u",
getTid(), uid);
const char *nameTmp = getName();
if (nameTmp) {
name += android::base::StringPrintf(
"%*s%s", (int)std::max(12 - name.length(), (size_t)1),
"", nameTmp);
} else if ((nameTmp = stat.uidToName(uid))) {
// if we do not have a PID name, lets punt to try UID name?
name += android::base::StringPrintf(
"%*s%s", (int)std::max(12 - name.length(), (size_t)1),
"", nameTmp);
free(const_cast<char *>(nameTmp));
// We tried, better to not have a name at all, we still
// have TID/UID by number to report in any case.
}
std::string size = android::base::StringPrintf("%zu",
getSizes());
std::string pruned = "";
size_t dropped = getDropped();
if (dropped) {
pruned = android::base::StringPrintf("%zu", dropped);
}
return formatLine(name, size, pruned);
}
std::string TagEntry::formatHeader(const std::string &name, log_id_t id) const {
bool isprune = worstUidEnabledForLogid(id);
return formatLine(name,
std::string("Size"),
std::string(isprune ? "Prune" : ""))
+ formatLine(std::string(" TAG/UID TAGNAME"),
std::string("BYTES"),
std::string(isprune ? "NUM" : ""));
}
std::string TagEntry::format(const LogStatistics & /* stat */, log_id_t /* id */) const {
std::string name;
uid_t uid = getUid();
if (uid == (uid_t)-1) {
name = android::base::StringPrintf("%7u",
getKey());
} else {
name = android::base::StringPrintf("%7u/%u",
getKey(), uid);
}
size_t len = 0;
const char *nameTmp = getName(len);
if (nameTmp) {
name += android::base::StringPrintf(
"%*s%.*s", (int)std::max(14 - name.length(), (size_t)1),
"", (int)len, nameTmp);
}
std::string size = android::base::StringPrintf("%zu",
getSizes());
std::string pruned = "";
size_t dropped = getDropped();
if (dropped) {
pruned = android::base::StringPrintf("%zu", dropped);
}
return formatLine(name, size, pruned);
}
std::string LogStatistics::format(uid_t uid, pid_t pid,
unsigned int logMask) const {
static const unsigned short spaces_total = 19;
// Report on total logging, current and for all time
std::string output = "size/num";
size_t oldLength;
short spaces = 1;
log_id_for_each(id) {
if (!(logMask & (1 << id))) {
continue;
}
oldLength = output.length();
if (spaces < 0) {
spaces = 0;
}
output += android::base::StringPrintf("%*s%s", spaces, "",
android_log_id_to_name(id));
spaces += spaces_total + oldLength - output.length();
}
spaces = 4;
output += "\nTotal";
log_id_for_each(id) {
if (!(logMask & (1 << id))) {
continue;
}
oldLength = output.length();
if (spaces < 0) {
spaces = 0;
}
output += android::base::StringPrintf("%*s%zu/%zu", spaces, "",
sizesTotal(id),
elementsTotal(id));
spaces += spaces_total + oldLength - output.length();
}
spaces = 6;
output += "\nNow";
log_id_for_each(id) {
if (!(logMask & (1 << id))) {
continue;
}
size_t els = elements(id);
if (els) {
oldLength = output.length();
if (spaces < 0) {
spaces = 0;
}
output += android::base::StringPrintf("%*s%zu/%zu", spaces, "",
sizes(id), els);
spaces -= output.length() - oldLength;
}
spaces += spaces_total;
}
// Report on Chattiest
std::string name;
// Chattiest by application (UID)
log_id_for_each(id) {
if (!(logMask & (1 << id))) {
continue;
}
name = (uid == AID_ROOT)
? "Chattiest UIDs in %s log buffer:"
: "Logging for your UID in %s log buffer:";
output += uidTable[id].format(*this, uid, pid, name, id);
}
if (enable) {
name = ((uid == AID_ROOT) && !pid)
? "Chattiest PIDs:"
: "Logging for this PID:";
output += pidTable.format(*this, uid, pid, name);
name = "Chattiest TIDs";
if (pid) {
name += android::base::StringPrintf(" for PID %d", pid);
}
name += ":";
output += tidTable.format(*this, uid, pid, name);
}
if (enable && (logMask & (1 << LOG_ID_EVENTS))) {
name = "Chattiest events log buffer TAGs";
if (pid) {
name += android::base::StringPrintf(" for PID %d", pid);
}
name += ":";
output += tagTable.format(*this, uid, pid, name, LOG_ID_EVENTS);
}
if (enable && (logMask & (1 << LOG_ID_SECURITY))) {
name = "Chattiest security log buffer TAGs";
if (pid) {
name += android::base::StringPrintf(" for PID %d", pid);
}
name += ":";
output += securityTagTable.format(*this, uid, pid, name, LOG_ID_SECURITY);
}
return output;
}
namespace android {
uid_t pidToUid(pid_t pid) {
char buffer[512];
snprintf(buffer, sizeof(buffer), "/proc/%u/status", pid);
FILE *fp = fopen(buffer, "r");
if (fp) {
while (fgets(buffer, sizeof(buffer), fp)) {
int uid;
if (sscanf(buffer, "Uid: %d", &uid) == 1) {
fclose(fp);
return uid;
}
}
fclose(fp);
}
return AID_LOGD; // associate this with the logger
}
}
uid_t LogStatistics::pidToUid(pid_t pid) {
return pidTable.add(pid)->second.getUid();
}
// caller must free character string
const char *LogStatistics::pidToName(pid_t pid) const {
// An inconvenient truth ... getName() can alter the object
pidTable_t &writablePidTable = const_cast<pidTable_t &>(pidTable);
const char *name = writablePidTable.add(pid)->second.getName();
if (!name) {
return NULL;
}
return strdup(name);
}
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