platform_system_core/logd/LogBufferElement.cpp

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/*
* Copyright (C) 2012-2014 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 <ctype.h>
#include <endian.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <log/logger.h>
#include <private/android_logger.h>
#include "LogBufferElement.h"
#include "LogCommand.h"
#include "LogReader.h"
const uint64_t LogBufferElement::FLUSH_ERROR(0);
atomic_int_fast64_t LogBufferElement::sequence;
LogBufferElement::LogBufferElement(log_id_t log_id, log_time realtime,
uid_t uid, pid_t pid, pid_t tid,
const char *msg, unsigned short len) :
mLogId(log_id),
mUid(uid),
mPid(pid),
mTid(tid),
mMsgLen(len),
mSequence(sequence.fetch_add(1, memory_order_relaxed)),
mRealTime(realtime) {
mMsg = new char[len];
memcpy(mMsg, msg, len);
}
LogBufferElement::~LogBufferElement() {
delete [] mMsg;
}
uint32_t LogBufferElement::getTag() const {
if ((mLogId != LOG_ID_EVENTS) || !mMsg || (mMsgLen < sizeof(uint32_t))) {
return 0;
}
return le32toh(reinterpret_cast<android_event_header_t *>(mMsg)->tag);
}
// caller must own and free character string
char *android::tidToName(pid_t tid) {
char *retval = NULL;
char buffer[256];
snprintf(buffer, sizeof(buffer), "/proc/%u/comm", tid);
int fd = open(buffer, O_RDONLY);
if (fd >= 0) {
ssize_t ret = read(fd, buffer, sizeof(buffer));
if (ret >= (ssize_t)sizeof(buffer)) {
ret = sizeof(buffer) - 1;
}
while ((ret > 0) && isspace(buffer[ret - 1])) {
--ret;
}
if (ret > 0) {
buffer[ret] = '\0';
retval = strdup(buffer);
}
close(fd);
}
// if nothing for comm, check out cmdline
char *name = android::pidToName(tid);
if (!retval) {
retval = name;
name = NULL;
}
// check if comm is truncated, see if cmdline has full representation
if (name) {
// impossible for retval to be NULL if name not NULL
size_t retval_len = strlen(retval);
size_t name_len = strlen(name);
// KISS: ToDo: Only checks prefix truncated, not suffix, or both
if ((retval_len < name_len) && !strcmp(retval, name + name_len - retval_len)) {
free(retval);
retval = name;
} else {
free(name);
}
}
return retval;
}
// assumption: mMsg == NULL
size_t LogBufferElement::populateDroppedMessage(char *&buffer,
LogBuffer *parent) {
static const char tag[] = "logd";
static const char format_uid[] = "uid=%u%s too chatty%s, expire %u line%s";
char *name = parent->uidToName(mUid);
char *commName = android::tidToName(mTid);
if (!commName && (mTid != mPid)) {
commName = android::tidToName(mPid);
}
if (!commName) {
commName = parent->pidToName(mPid);
}
if (name && commName && !strcmp(name, commName)) {
free(commName);
commName = NULL;
}
if (name) {
char *p = NULL;
asprintf(&p, "(%s)", name);
if (p) {
free(name);
name = p;
}
}
if (commName) {
char *p = NULL;
asprintf(&p, " comm=%s", commName);
if (p) {
free(commName);
commName = p;
}
}
// identical to below to calculate the buffer size required
size_t len = snprintf(NULL, 0, format_uid, mUid, name ? name : "",
commName ? commName : "",
mDropped, (mDropped > 1) ? "s" : "");
size_t hdrLen;
if (mLogId == LOG_ID_EVENTS) {
hdrLen = sizeof(android_log_event_string_t);
} else {
hdrLen = 1 + sizeof(tag);
}
buffer = static_cast<char *>(calloc(1, hdrLen + len + 1));
if (!buffer) {
free(name);
free(commName);
return 0;
}
size_t retval = hdrLen + len;
if (mLogId == LOG_ID_EVENTS) {
android_log_event_string_t *e = reinterpret_cast<android_log_event_string_t *>(buffer);
e->header.tag = htole32(LOGD_LOG_TAG);
e->type = EVENT_TYPE_STRING;
e->length = htole32(len);
} else {
++retval;
buffer[0] = ANDROID_LOG_INFO;
strcpy(buffer + 1, tag);
}
snprintf(buffer + hdrLen, len + 1, format_uid, mUid, name ? name : "",
commName ? commName : "",
mDropped, (mDropped > 1) ? "s" : "");
free(name);
free(commName);
return retval;
}
uint64_t LogBufferElement::flushTo(SocketClient *reader, LogBuffer *parent) {
struct logger_entry_v3 entry;
memset(&entry, 0, sizeof(struct logger_entry_v3));
entry.hdr_size = sizeof(struct logger_entry_v3);
entry.lid = mLogId;
entry.pid = mPid;
entry.tid = mTid;
entry.sec = mRealTime.tv_sec;
entry.nsec = mRealTime.tv_nsec;
struct iovec iovec[2];
iovec[0].iov_base = &entry;
iovec[0].iov_len = sizeof(struct logger_entry_v3);
char *buffer = NULL;
if (!mMsg) {
entry.len = populateDroppedMessage(buffer, parent);
if (!entry.len) {
return mSequence;
}
iovec[1].iov_base = buffer;
} else {
entry.len = mMsgLen;
iovec[1].iov_base = mMsg;
}
iovec[1].iov_len = entry.len;
uint64_t retval = reader->sendDatav(iovec, 2) ? FLUSH_ERROR : mSequence;
if (buffer) {
free(buffer);
}
return retval;
}