net: retrieve if unix network is available only once for AIX

The previous version was executing "oslevel -s" everytime testableNetwork
was called with unix/unixgram network. The current version retrieves if
the network is possible only once at the beginning of the tests.

This is clearly faster:
ok      net     74.045s
ok      net     5.098s

Change-Id: I12549da27721f85c007cf17cab5cfdbfeb839cf6
Reviewed-on: https://go-review.googlesource.com/c/go/+/171717
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/net/platform_test.go b/src/net/platform_test.go
index 7e9ad70d19b28943d81952d289caa06f09c62daa..10f55c971df198f87b7e7ff36d4092a8bd4a874d 100644 (file)
--- a/src/net/platform_test.go
+++ b/src/net/platform_test.go
@@ -14,6 +14,23 @@ import (
        "testing"
 )
 
+var unixEnabledOnAIX bool
+
+func init() {
+       if runtime.GOOS == "aix" {
+               // Unix network isn't properly working on AIX 7.2 with
+               // Technical Level < 2.
+               // The information is retrieved only once in this init()
+               // instead of everytime testableNetwork is called.
+               out, _ := exec.Command("oslevel", "-s").Output()
+               if len(out) >= len("7200-XX-ZZ-YYMM") { // AIX 7.2, Tech Level XX, Service Pack ZZ, date YYMM
+                       aixVer := string(out[:4])
+                       tl, _ := strconv.Atoi(string(out[5:7]))
+                       unixEnabledOnAIX = aixVer > "7200" || (aixVer == "7200" && tl >= 2)
+               }
+       }
+}
+
 // testableNetwork reports whether network is testable on the current
 // platform configuration.
 func testableNetwork(network string) bool {
@@ -38,15 +55,7 @@ func testableNetwork(network string) bool {
                case "android", "nacl", "plan9", "windows":
                        return false
                case "aix":
-                       // Unix network isn't properly working on AIX 7.2 with Technical Level < 2
-                       out, err := exec.Command("oslevel", "-s").Output()
-                       if err != nil {
-                               return false
-                       }
-                       if tl, err := strconv.Atoi(string(out[5:7])); err != nil || tl < 2 {
-                               return false
-                       }
-                       return true
+                       return unixEnabledOnAIX
                }
                // iOS does not support unix, unixgram.
                if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {