commit e275d6d72db1868056a204e8483a7346a28cb8d6
author Tom Cherry <tomcherry@google.com> Mon Dec 11 23:31:33 2017 -0800
committer Tom Cherry <tomcherry@google.com> Mon Dec 18 15:17:55 2017 -0800
tree 3191e33ca242518f7d486c6b37212c7f682498b0
parent 721a5305e24b69b68ecc9431526f32131abc8f6c

Split properties into their own class to make testing better

Reinitializing system properties can result in crashes later in the
program, and is generally not recommended or even supported.  This
change moves the actual logic for system properties into a class that
can be tested in isolation, without reinitializing the actual system
property area used in libc.

Bug: 62197783
Test: boot devices, ensure properties work
Test: system property unit tests and benchmarks
Change-Id: I9ae6e1b56c62f51a4d3fdb5b62b8926cef545649

libc/system_properties/contexts_split.cpp

diff --git a/libc/system_properties/contexts_split.cpp b/libc/system_properties/contexts_split.cpp
index 77f2069..b8afa29 100644
--- a/libc/system_properties/contexts_split.cpp
+++ b/libc/system_properties/contexts_split.cpp
@@ -26,22 +26,23 @@
  * SUCH DAMAGE.
  */
 
-#include "contexts_split.h"
+#include "system_properties/contexts_split.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
 
 #include <async_safe/log.h>
 
-#include "context_node.h"
-#include "property_filename.h"
+#include "system_properties/context_node.h"
+#include "system_properties/system_properties.h"
 
 class ContextListNode : public ContextNode {
  public:
-  ContextListNode(ContextListNode* next, const char* context)
-      : ContextNode(strdup(context)), next(next) {
+  ContextListNode(ContextListNode* next, const char* context, const char* filename)
+      : ContextNode(strdup(context), filename), next(next) {
   }
 
   ~ContextListNode() {
@@ -194,8 +195,7 @@
 
 bool ContextsSplit::MapSerialPropertyArea(bool access_rw, bool* fsetxattr_failed) {
   char filename[PROP_FILENAME_MAX];
-  int len = async_safe_format_buffer(filename, sizeof(filename), "%s/properties_serial",
-                                     property_filename);
+  int len = async_safe_format_buffer(filename, sizeof(filename), "%s/properties_serial", filename_);
   if (len < 0 || len > PROP_FILENAME_MAX) {
     serial_prop_area_ = nullptr;
     return false;
@@ -245,7 +245,7 @@
     if (old_context) {
       ListAddAfterLen(&prefixes_, prop_prefix, old_context);
     } else {
-      ListAdd(&contexts_, context);
+      ListAdd(&contexts_, context, filename_);
       ListAddAfterLen(&prefixes_, prop_prefix, contexts_);
     }
     free(prop_prefix);
@@ -285,26 +285,28 @@
   return true;
 }
 
-bool ContextsSplit::Initialize(bool writable) {
+bool ContextsSplit::Initialize(bool writable, const char* filename, bool* fsetxattr_failed) {
+  filename_ = filename;
   if (!InitializeProperties()) {
     return false;
   }
 
   if (writable) {
-    mkdir(property_filename, S_IRWXU | S_IXGRP | S_IXOTH);
+    mkdir(filename_, S_IRWXU | S_IXGRP | S_IXOTH);
     bool open_failed = false;
-    bool fsetxattr_failed = false;
+    if (fsetxattr_failed) {
+      *fsetxattr_failed = false;
+    }
+
     ListForEach(contexts_, [&fsetxattr_failed, &open_failed](ContextListNode* l) {
-      if (!l->Open(true, &fsetxattr_failed)) {
+      if (!l->Open(true, fsetxattr_failed)) {
         open_failed = true;
       }
     });
-    if (open_failed || !MapSerialPropertyArea(true, &fsetxattr_failed)) {
+    if (open_failed || !MapSerialPropertyArea(true, fsetxattr_failed)) {
       FreeAndUnmap();
       return false;
     }
-
-    return !fsetxattr_failed;
   } else {
     if (!MapSerialPropertyArea(false, nullptr)) {
       FreeAndUnmap();