From 81f407be3621988a791b175c88a4b7f2ca2dead5 Mon Sep 17 00:00:00 2001
From: Mark Salyzyn <salyzyn@google.com>
Date: Thu, 25 Feb 2016 09:02:09 -0800
Subject: [PATCH] liblog: __android_log_error_write use event list library

Switch to the event list library to compose the associated event.

SideEffects: Instead of composing event on a stack buffer of 512
             bytes in size, a PAGE is allocated temporarily.

Bug: 27356456
Change-Id: Ic15a87f49385834c2287ed82c26439b2c5eb4f77
---
 liblog/Android.mk        |  9 ++---
 liblog/log_event_write.c | 81 ++++++++++------------------------------
 2 files changed, 24 insertions(+), 66 deletions(-)

diff --git a/liblog/Android.mk b/liblog/Android.mk
index c7b76d87a..dd5b518e7 100644
--- a/liblog/Android.mk
+++ b/liblog/Android.mk
@@ -24,11 +24,10 @@ include $(CLEAR_VARS)
 # so make sure we do not regret hard-coding it as follows:
 liblog_cflags := -DLIBLOG_LOG_TAG=1005
 
-liblog_host_sources := logd_write.c log_event_write.c fake_log_device.c event.logtags
-liblog_target_sources := logd_write.c log_event_write.c event_tag_map.c log_time.cpp log_is_loggable.c
-liblog_target_sources += logprint.c
-liblog_target_sources += log_read.c
-liblog_target_sources += log_event_list.c
+liblog_sources := logd_write.c log_event_list.c log_event_write.c
+liblog_host_sources := $(liblog_sources) fake_log_device.c event.logtags
+liblog_target_sources := $(liblog_sources) event_tag_map.c
+liblog_target_sources += log_time.cpp log_is_loggable.c logprint.c log_read.c
 
 # Shared and static library for host
 # ========================================================
diff --git a/liblog/log_event_write.c b/liblog/log_event_write.c
index 0bc42d548..ad42edd30 100644
--- a/liblog/log_event_write.c
+++ b/liblog/log_event_write.c
@@ -15,74 +15,33 @@
  */
 
 #include <errno.h>
-#include <string.h>
 
 #include <log/log.h>
-#include <log/logger.h>
 
-#define MAX_EVENT_PAYLOAD 512
 #define MAX_SUBTAG_LEN 32
 
-static inline void copy4LE(uint8_t *buf, size_t pos, int val)
+int __android_log_error_write(int tag, const char *subTag, int32_t uid,
+                              const char *data, uint32_t dataLen)
 {
-    buf[pos] = val & 0xFF;
-    buf[pos+1] = (val >> 8) & 0xFF;
-    buf[pos+2] = (val >> 16) & 0xFF;
-    buf[pos+3] = (val >> 24) & 0xFF;
-}
+    int ret = -EINVAL;
 
-int __android_log_error_write(int tag, const char *subTag, int32_t uid, const char *data,
-                              uint32_t dataLen)
-{
-    uint8_t buf[MAX_EVENT_PAYLOAD];
-    size_t pos = 0;
-    uint32_t subTagLen = 0;
-    uint32_t roomLeftForData = 0;
+    if (subTag && (data || !dataLen)) {
+        android_log_context ctx = create_android_logger(tag);
 
-    if ((subTag == NULL) || ((data == NULL) && (dataLen != 0))) return -EINVAL;
-
-    subTagLen = strlen(subTag);
-
-    // Truncate subtags that are too long.
-    subTagLen = subTagLen > MAX_SUBTAG_LEN ? MAX_SUBTAG_LEN : subTagLen;
-
-    // Truncate dataLen if it is too long.
-    roomLeftForData = MAX_EVENT_PAYLOAD -
-            (1 + // EVENT_TYPE_LIST
-             1 + // Number of elements in list
-             1 + // EVENT_TYPE_STRING
-             sizeof(subTagLen) +
-             subTagLen +
-             1 + // EVENT_TYPE_INT
-             sizeof(uid) +
-             1 + // EVENT_TYPE_STRING
-             sizeof(dataLen));
-    dataLen = dataLen > roomLeftForData ? roomLeftForData : dataLen;
-
-    buf[pos++] = EVENT_TYPE_LIST;
-    buf[pos++] = 3; // Number of elements in the list (subTag, uid, data)
-
-    // Write sub tag.
-    buf[pos++] = EVENT_TYPE_STRING;
-    copy4LE(buf, pos, subTagLen);
-    pos += 4;
-    memcpy(&buf[pos], subTag, subTagLen);
-    pos += subTagLen;
-
-    // Write UID.
-    buf[pos++] = EVENT_TYPE_INT;
-    copy4LE(buf, pos, uid);
-    pos += 4;
-
-    // Write data.
-    buf[pos++] = EVENT_TYPE_STRING;
-    copy4LE(buf, pos, dataLen);
-    pos += 4;
-    if (dataLen != 0)
-    {
-        memcpy(&buf[pos], data, dataLen);
-        pos += dataLen;
+        ret = -ENOMEM;
+        if (ctx) {
+            ret = android_log_write_string8_len(ctx, subTag, MAX_SUBTAG_LEN);
+            if (ret >= 0) {
+                ret = android_log_write_int32(ctx, uid);
+                if (ret >= 0) {
+                    ret = android_log_write_string8_len(ctx, data, dataLen);
+                    if (ret >= 0) {
+                        ret = android_log_write_list(ctx, LOG_ID_EVENTS);
+                    }
+                }
+            }
+            android_log_destroy(&ctx);
+        }
     }
-
-    return __android_log_bwrite(tag, buf, pos);
+    return ret;
 }