Merge "logd: initial checkin."

1 files changed, 214 insertions, 0 deletions

diff --git a/logd/LogBuffer.cpp b/logd/LogBuffer.cpp
new file mode 100644
index 0000000..8b273e2
--- /dev/null
+++ b/logd/LogBuffer.cpp
@@ -0,0 +1,214 @@
+/*
+ * 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 <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <log/logger.h>
+
+#include "LogBuffer.h"
+#include "LogReader.h"
+
+#define LOG_BUFFER_SIZE (256 * 1024) // Tuned on a per-platform basis here?
+
+LogBuffer::LogBuffer(LastLogTimes *times)
+        : mTimes(*times) {
+    int i;
+    for (i = 0; i < LOG_ID_MAX; i++) {
+        mSizes[i] = 0;
+        mElements[i] = 0;
+    }
+    pthread_mutex_init(&mLogElementsLock, NULL);
+}
+
+void LogBuffer::log(log_id_t log_id, struct timespec realtime,
+                    uid_t uid, pid_t pid, const char *msg,
+                    unsigned short len) {
+    if ((log_id >= LOG_ID_MAX) || (log_id < 0)) {
+        return;
+    }
+    LogBufferElement *elem = new LogBufferElement(log_id, realtime,
+                                                  uid, pid, msg, len);
+
+    pthread_mutex_lock(&mLogElementsLock);
+
+    // Insert elements in time sorted order if possible
+    //  NB: if end is region locked, place element at end of list
+    LogBufferElementCollection::iterator it = mLogElements.end();
+    LogBufferElementCollection::iterator last = it;
+    while (--it != mLogElements.begin()) {
+        if ((*it)->getRealTime() <= elem->getRealTime()) {
+            break;
+        }
+        last = it;
+    }
+    if (last == mLogElements.end()) {
+        mLogElements.push_back(elem);
+    } else {
+        log_time end;
+        bool end_set = false;
+        bool end_always = false;
+
+        LogTimeEntry::lock();
+
+        LastLogTimes::iterator t = mTimes.begin();
+        while(t != mTimes.end()) {
+            LogTimeEntry *entry = (*t);
+            if (entry->owned_Locked()) {
+                if (!entry->mNonBlock) {
+                    end_always = true;
+                    break;
+                }
+                if (!end_set || (end <= entry->mEnd)) {
+                    end = entry->mEnd;
+                    end_set = true;
+                }
+            }
+            t++;
+        }
+
+        if (end_always
+         || (end_set && (end >= (*last)->getMonotonicTime()))) {
+            mLogElements.push_back(elem);
+        } else {
+            mLogElements.insert(last,elem);
+        }
+
+        LogTimeEntry::unlock();
+    }
+
+    mSizes[log_id] += len;
+    mElements[log_id]++;
+    maybePrune(log_id);
+    pthread_mutex_unlock(&mLogElementsLock);
+}
+
+// If we're using more than 256K of memory for log entries, prune
+// 10% of the log entries.
+//
+// mLogElementsLock must be held when this function is called.
+void LogBuffer::maybePrune(log_id_t id) {
+    if (mSizes[id] > LOG_BUFFER_SIZE) {
+        prune(id, mElements[id] / 10);
+    }
+}
+
+// prune "pruneRows" of type "id" from the buffer.
+//
+// mLogElementsLock must be held when this function is called.
+void LogBuffer::prune(log_id_t id, unsigned long pruneRows) {
+    LogTimeEntry *oldest = NULL;
+
+    LogTimeEntry::lock();
+
+    // Region locked?
+    LastLogTimes::iterator t = mTimes.begin();
+    while(t != mTimes.end()) {
+        LogTimeEntry *entry = (*t);
+        if (entry->owned_Locked()
+                && (!oldest || (oldest->mStart > entry->mStart))) {
+            oldest = entry;
+        }
+        t++;
+    }
+
+    LogBufferElementCollection::iterator it = mLogElements.begin();
+    while((pruneRows > 0) && (it != mLogElements.end())) {
+        LogBufferElement *e = *it;
+        if (e->getLogId() == id) {
+            if (oldest && (oldest->mStart <= e->getMonotonicTime())) {
+                if (mSizes[id] > (2 * LOG_BUFFER_SIZE)) {
+                    // kick a misbehaving log reader client off the island
+                    oldest->release_Locked();
+                } else {
+                    oldest->triggerSkip_Locked(pruneRows);
+                }
+                break;
+            }
+            it = mLogElements.erase(it);
+            mSizes[id] -= e->getMsgLen();
+            mElements[id]--;
+            delete e;
+            pruneRows--;
+        } else {
+            it++;
+        }
+    }
+
+    LogTimeEntry::unlock();
+}
+
+// clear all rows of type "id" from the buffer.
+void LogBuffer::clear(log_id_t id) {
+    pthread_mutex_lock(&mLogElementsLock);
+    prune(id, ULONG_MAX);
+    pthread_mutex_unlock(&mLogElementsLock);
+}
+
+// get the used space associated with "id".
+unsigned long LogBuffer::getSizeUsed(log_id_t id) {
+    pthread_mutex_lock(&mLogElementsLock);
+    unsigned long retval = mSizes[id];
+    pthread_mutex_unlock(&mLogElementsLock);
+    return retval;
+}
+
+// get the total space allocated to "id"
+unsigned long LogBuffer::getSize(log_id_t /*id*/) {
+    return LOG_BUFFER_SIZE;
+}
+
+struct timespec LogBuffer::flushTo(
+        SocketClient *reader, const struct timespec start, bool privileged,
+        bool (*filter)(const LogBufferElement *element, void *arg), void *arg) {
+    LogBufferElementCollection::iterator it;
+    log_time max = start;
+    uid_t uid = reader->getUid();
+
+    pthread_mutex_lock(&mLogElementsLock);
+    for (it = mLogElements.begin(); it != mLogElements.end(); ++it) {
+        LogBufferElement *element = *it;
+
+        if (!privileged && (element->getUid() != uid)) {
+            continue;
+        }
+
+        if (element->getMonotonicTime() <= start) {
+            continue;
+        }
+
+        // NB: calling out to another object with mLogElementsLock held (safe)
+        if (filter && !(*filter)(element, arg)) {
+            continue;
+        }
+
+        pthread_mutex_unlock(&mLogElementsLock);
+
+        // range locking in LastLogTimes looks after us
+        max = element->flushTo(reader);
+
+        if (max == element->FLUSH_ERROR) {
+            return max;
+        }
+
+        pthread_mutex_lock(&mLogElementsLock);
+    }
+    pthread_mutex_unlock(&mLogElementsLock);
+
+    return max;
+}