commit bd5c72638cc156fbf5117b6b4d54dabb3b9f1909
author Mark Salyzyn <salyzyn@google.com> Thu Feb 25 08:41:25 2016 -0800
committer Mark Salyzyn <salyzyn@google.com> Thu Feb 25 15:53:00 2016 -0800
tree 2036aca936a48f588ecc4adab38356f6d7bdba8e
parent b7be83b867f08c411471dcb22c34f69124cb41a6

liblog: add android_log_write_string8_len

(cherry pick from commit 67d7eafd56010f154137e4316e938f802b2b0732)

android_log_write_string8_len(android_log_context ctx,
                              const char *value, size_t maxlen)

Caps the supplied string to a maxlen length. Alter API to handle
a NULL pointer for the value string for this and
android_log_write_string8() and instead of returning -EINVAL,
act like a null string "" was supplied to preserve the list
location. API is also changed to report the number of characters
actually placed into the android_log_context.

Bug: 27356456
Bug: 19235719
Change-Id: I6a03d405eac1d741555dd05555513ec691e7a46e

include/log/log.h

diff --git a/include/log/log.h b/include/log/log.h
index 6ad6f0a..e606a84 100644
--- a/include/log/log.h
+++ b/include/log/log.h
@@ -589,6 +589,8 @@
 int android_log_write_int32(android_log_context ctx, int32_t value);
 int android_log_write_int64(android_log_context ctx, int64_t value);
 int android_log_write_string8(android_log_context ctx, const char *value);
+int android_log_write_string8_len(android_log_context ctx,
+                                  const char *value, size_t maxlen);
 int android_log_write_float32(android_log_context ctx, float value);
 
 /* Submit the composed list context to the specified logger id */

liblog/log_event_list.c

diff --git a/liblog/log_event_list.c b/liblog/log_event_list.c
index 50a27c0..2213f21 100644
--- a/liblog/log_event_list.c
+++ b/liblog/log_event_list.c
@@ -195,9 +195,10 @@
     return 0;
 }
 
-int android_log_write_string8(android_log_context ctx, const char *value) {
+int android_log_write_string8_len(android_log_context ctx,
+                                  const char *value, size_t maxlen) {
     size_t needed;
-    int32_t len;
+    ssize_t len;
     android_log_context_internal *context;
 
     context = (android_log_context_internal *)ctx;
@@ -208,13 +209,13 @@
         return -EIO;
     }
     if (!value) {
-        return -EINVAL;
+        value = "";
     }
-    len = strlen(value);
-    needed = sizeof(uint8_t) + sizeof(len) + len;
+    len = strnlen(value, maxlen);
+    needed = sizeof(uint8_t) + sizeof(int32_t) + len;
     if ((context->pos + needed) > MAX_EVENT_PAYLOAD) {
         /* Truncate string for delivery */
-        len = MAX_EVENT_PAYLOAD - context->pos - 1 - sizeof(len);
+        len = MAX_EVENT_PAYLOAD - context->pos - 1 - sizeof(int32_t);
         if (len <= 0) {
             context->overflow = true;
             return -EIO;
@@ -223,9 +224,15 @@
     context->count[context->list_nest_depth]++;
     context->storage[context->pos + 0] = EVENT_TYPE_STRING;
     copy4LE(&context->storage[context->pos + 1], len);
-    memcpy(&context->storage[context->pos + 5], value, len);
+    if (len) {
+        memcpy(&context->storage[context->pos + 5], value, len);
+    }
     context->pos += needed;
-    return 0;
+    return len;
+}
+
+int android_log_write_string8(android_log_context ctx, const char *value) {
+    return android_log_write_string8_len(ctx, value, MAX_EVENT_PAYLOAD);
 }
 
 int android_log_write_float32(android_log_context ctx, float value) {