Implement SysInfo::HardwareModelName() on iOS.

base/sys_info_ios.mm

Index: base/sys_info_ios.mm
diff --git a/base/sys_info_ios.mm b/base/sys_info_ios.mm
index 9a329b9f0924bbdefce908cd51de4a6488c574f0..9ffc525405ff1d5a81b631f416053800eb35c8a6 100644
--- a/base/sys_info_ios.mm
+++ b/base/sys_info_ios.mm
@@ -20,6 +20,23 @@
 
 namespace base {
 
+namespace {
+
+// Queries sysctlbyname() for the given key and returns the value from the
+// system or the empty string on failure.
+std::string GetSysctlValue(const char* key_name) {
+  char value[256];
+  size_t len = arraysize(value);
+  if (sysctlbyname(key_name, &value, &len, nullptr, 0) == 0) {
+    DCHECK_GE(len, 1u);
+    DCHECK_EQ('\0', value[len - 1]);
+    return std::string(value, len - 1);
+  }
+  return std::string();
+}
+
+}  // namespace
+
 // static
 std::string SysInfo::OperatingSystemName() {
   static dispatch_once_t get_system_name_once;
@@ -94,11 +111,14 @@ int64_t SysInfo::AmountOfAvailablePhysicalMemory() {
 
 // static
 std::string SysInfo::CPUModelName() {
-  char name[256];
-  size_t len = arraysize(name);
-  if (sysctlbyname("machdep.cpu.brand_string", &name, &len, NULL, 0) == 0)
-    return name;
-  return std::string();
+  return GetSysctlValue("machdep.cpu.brand_string");
+}
+
+// static
+std::string SysInfo::HardwareModelName() {
+  // Note: This uses "hw.machine" instead of "hw.model" like the Mac code,

[Mark Mentovai, 2017/05/04 21:11:33]

You may want to bifurcate this so that it uses hw.machine when targeting a
device, and hw.model when targeting a simulator. Otherwise, the test you added
will fail for simulator builds, because there’s no comma in x86_64.

[Alexei Svitkine (slow), 2017/05/04 21:23:14]

Yuck. Done. Went with returning a fake "Simulator1,1" string rather than using
"hw.model".

+  // because "hw.model" doesn't always return the right string on some devices.
+  return GetSysctlValue("hw.machine");
 }
 
 }  // namespace base