[Fuchsia] use zx_system_get_version() instead of uname() in SysInfo

Previously base::SysInfo was using uname(), but uname() depends on
fuchsia.device.NameProvider API which may not be accessible in all
processes. This change updates SysInfo to use zx_system_get_version()
to get OS version.

Bug: 986952
Change-Id: Ie3324180040933a509124147efd743de1f112416
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1715631
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Auto-Submit: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680176}

base/system/sys_info_fuchsia.cc

@@ -4,11 +4,12 @@
 
 #include "base/system/sys_info.h"
 
-#include <sys/utsname.h>
 #include <zircon/syscalls.h>
 
+#include "base/fuchsia/fuchsia_logging.h"
 #include "base/logging.h"
 #include "base/threading/scoped_blocking_call.h"
+#include "build/build_config.h"
 
 namespace base {
 
@@ -58,45 +59,34 @@ int64_t SysInfo::AmountOfTotalDiskSpace(const FilePath& path) {
 
 // static
 std::string SysInfo::OperatingSystemVersion() {
-  struct utsname info;
-  if (uname(&info) < 0) {
-    NOTREACHED();
+  char result[64] = {};
+  zx_status_t status = zx_system_get_version(result, sizeof(result));
+  if (status != ZX_OK) {
+    ZX_DLOG(WARNING, status) << "zx_system_get_version";
     return std::string();
   }
-
-  return std::string(info.release);
+  return result;
 }
 
 // static
 void SysInfo::OperatingSystemVersionNumbers(int32_t* major_version,
                                             int32_t* minor_version,
                                             int32_t* bugfix_version) {
-  struct utsname info;
-  if (uname(&info) < 0) {
-    *major_version = 0;
-    *minor_version = 0;
-    *bugfix_version = 0;
-    return;
-  }
-  int num_read = sscanf(info.release, "%d.%d.%d", major_version, minor_version,
-                        bugfix_version);
-  if (num_read < 1)
-    *major_version = 0;
-  if (num_read < 2)
-    *minor_version = 0;
-  if (num_read < 3)
-    *bugfix_version = 0;
+  // Fuchsia doesn't have OS version numbers.
+  *major_version = 0;
+  *minor_version = 0;
+  *bugfix_version = 0;
 }
 
 // static
 std::string SysInfo::OperatingSystemArchitecture() {
-  struct utsname info;
-  if (uname(&info) < 0) {
-    NOTREACHED();
-    return std::string();
-  }
-
-  return info.machine;
+#if defined(ARCH_CPU_X86_64)
+  return "x86_64";
+#elif defined(ARCH_CPU_ARM64)
+  return "aarch64";
+#else
+#error Unsupported architecture.
+#endif
 }
 
 // static

base/system/sys_info_unittest.cc

@@ -115,7 +115,8 @@ TEST_F(SysInfoTest, MAYBE_AmountOfTotalDiskSpace) {
   EXPECT_GT(SysInfo::AmountOfTotalDiskSpace(tmp_path), 0) << tmp_path.value();
 }
 
-#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX)
+#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX) || \
+    defined(OS_FUCHSIA)
 TEST_F(SysInfoTest, OperatingSystemVersionNumbers) {
   int32_t os_major_version = -1;
   int32_t os_minor_version = -1;