commit 37c5d94cd4120fddb1b38fba0dc04cf7087e5ac5
author Alex Vakulenko <avakulenko@chromium.org> Tue Jun 17 18:17:43 2014 -0700
committer chrome-internal-fetch <chrome-internal-fetch@google.com> Wed Jun 18 08:46:08 2014 +0000
tree 3780e812b02cc0461199c5d83a15ba31c82510a8
parent 8a5322984f2d81bcbfd8d44c59747a11bd9b904b

shill: replace rand() with std::default_random_engine

Replace rand() with STL random number generator to have
superior quality of random numbers, thread safety and
stop linter from complaining.

BUG=None
TEST=Unit tests pass.

Change-Id: I80da776c70bbd8bffe10916554393621ad60131e
Reviewed-on: https://chromium-review.googlesource.com/204430
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>

default_profile.cc

diff --git a/default_profile.cc b/default_profile.cc
index c17c63f..1a7d828 100644
--- a/default_profile.cc
+++ b/default_profile.cc
@@ -4,6 +4,7 @@
 
 #include "shill/default_profile.h"
 
+#include <random>
 #include <vector>
 
 #include <base/files/file_path.h>
@@ -62,7 +63,8 @@
     : Profile(control, metrics, manager, Identifier(profile_id), "", true),
       storage_path_(storage_path),
       profile_id_(profile_id),
-      props_(manager_props) {
+      props_(manager_props),
+      random_engine_(time(nullptr)) {
   PropertyStore *store = this->mutable_store();
   store->RegisterConstBool(kArpGatewayProperty, &manager_props.arp_gateway);
   store->RegisterConstString(kCheckPortalListProperty,
@@ -117,8 +119,8 @@
   }
   if (!storage()->GetInt(kStorageId, kStorageConnectionIdSalt,
                          &manager_props->connection_id_salt)) {
-    srand(time(NULL));
-    manager_props->connection_id_salt = rand();  // NOLINT - rand
+    manager_props->connection_id_salt =
+        std::uniform_int_distribution<int>()(random_engine_);
   }
 }
 

default_profile.h

diff --git a/default_profile.h b/default_profile.h
index 60125fa..afae425 100644
--- a/default_profile.h
+++ b/default_profile.h
@@ -5,6 +5,7 @@
 #ifndef SHILL_DEFAULT_PROFILE_H_
 #define SHILL_DEFAULT_PROFILE_H_
 
+#include <random>
 #include <string>
 #include <vector>
 
@@ -84,6 +85,7 @@
   const base::FilePath storage_path_;
   const std::string profile_id_;
   const Manager::Properties &props_;
+  std::default_random_engine random_engine_;
 
   DISALLOW_COPY_AND_ASSIGN(DefaultProfile);
 };

ip_address_store.cc

diff --git a/ip_address_store.cc b/ip_address_store.cc
index 67c759e..eee5655 100644
--- a/ip_address_store.cc
+++ b/ip_address_store.cc
@@ -21,8 +21,7 @@
   return lhs.ToString() < rhs.ToString();
 }
 
-IPAddressStore::IPAddressStore() {
-  srand(time(NULL));
+IPAddressStore::IPAddressStore() : random_engine_(time(nullptr)) {
 }
 
 IPAddressStore::~IPAddressStore() {}
@@ -46,7 +45,8 @@
 IPAddress IPAddressStore::GetRandomIP() {
   if (ip_addresses_.empty())
     return IPAddress(IPAddress::kFamilyUnknown);
-  int index = rand() % ip_addresses_.size();  // NOLINT(runtime/threadsafe_fn)
+  std::uniform_int_distribution<int> uniform_rand(0, ip_addresses_.size() - 1);
+  int index = uniform_rand(random_engine_);
   IPAddresses::const_iterator cit = ip_addresses_.begin();
   advance(cit, index);
   return *cit;

ip_address_store.h

diff --git a/ip_address_store.h b/ip_address_store.h
index fd3ee04..966082e 100644
--- a/ip_address_store.h
+++ b/ip_address_store.h
@@ -5,6 +5,7 @@
 #ifndef SHILL_IP_ADDRESS_STORE_H_
 #define SHILL_IP_ADDRESS_STORE_H_
 
+#include <random>
 #include <set>
 
 #include "shill/ip_address.h"
@@ -43,6 +44,7 @@
 
  private:
   IPAddresses ip_addresses_;
+  std::default_random_engine random_engine_;
 
   DISALLOW_COPY_AND_ASSIGN(IPAddressStore);
 };