From: Shenghou Ma <minux.ma@gmail.com>
Date: Sat, 1 Mar 2014 23:56:50 +0000 (-0500)
Subject: syscall: workaround Dragonfly BSD kernel exec bug
X-Git-Tag: go1.3beta1~522
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=5fbd6044bce8b032c72378a0db5106c235df9067;p=gostls13.git

syscall: workaround Dragonfly BSD kernel exec bug
See also CL 4259056 for FreeBSD.

Test program:
// exec.go
package main
import (
        "log"
        "os"
        "os/exec"
        "runtime"
)
func main() {
        path := runtime.GOROOT() + "/src/pkg/net/http/cgi/testdata"
        cmd := &exec.Cmd{
                Path:   "test.cgi",
                Args:   []string{path + "/test.cgi"},
                Dir:    path
                Stdout: os.Stdout}
        if err := cmd.Start(); err != nil {
                log.Fatal(err)
        }
        if err := cmd.Wait(); err != nil {
                log.Fatal(err)
        }
}

$ go run exec.go
2014/03/01 15:52:41 fork/exec test.cgi: argument list too long

LGTM=iant
R=rsc, iant
CC=golang-codereviews
https://golang.org/cl/69970044
---

diff --git a/src/pkg/syscall/exec_unix.go b/src/pkg/syscall/exec_unix.go
index 93670daeed..890bfdc227 100644
--- a/src/pkg/syscall/exec_unix.go
+++ b/src/pkg/syscall/exec_unix.go
@@ -158,7 +158,7 @@ func forkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err error)
 		return 0, err
 	}
 
-	if runtime.GOOS == "freebsd" && len(argv[0]) > len(argv0) {
+	if (runtime.GOOS == "freebsd" || runtime.GOOS == "dragonfly") && len(argv[0]) > len(argv0) {
 		argvp[0] = argv0p
 	}