net: remove unused cname return from cgoLookupIPCNAME

Change-Id: I4f9b84696f55c6b381de60682f8b242098b95b75
GitHub-Last-Rev: 74a6013a9e668119a0895c1250c3d4592bfd4072
GitHub-Pull-Request: golang/go#58402
Reviewed-on: https://go-review.googlesource.com/c/go/+/466335
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

3 files changed, 6 insertions, 18 deletions

diff --git a/src/net/cgo_unix.go b/src/net/cgo_unix.go
index 6e43e8271a..b90b579ffc 100644
--- a/src/net/cgo_unix.go
+++ b/src/net/cgo_unix.go
@@ -37,7 +37,6 @@ type portLookupResult struct {
 
 type ipLookupResult struct {
 	addrs []IPAddr
-	cname string
 	err   error
 }
 
@@ -133,7 +132,7 @@ func cgoPortLookup(result chan<- portLookupResult, hints *_C_struct_addrinfo, ne
 	result <- portLookupResult{port, err}
 }
 
-func cgoLookupIPCNAME(network, name string) (addrs []IPAddr, cname string, err error) {
+func cgoLookupHostIP(network, name string) (addrs []IPAddr, err error) {
 	acquireThread()
 	defer releaseThread()
 
@@ -175,19 +174,10 @@ func cgoLookupIPCNAME(network, name string) (addrs []IPAddr, cname string, err e
 			isTemporary = addrinfoErrno(gerrno).Temporary()
 		}
 
-		return nil, "", &DNSError{Err: err.Error(), Name: name, IsNotFound: isErrorNoSuchHost, IsTemporary: isTemporary}
+		return nil, &DNSError{Err: err.Error(), Name: name, IsNotFound: isErrorNoSuchHost, IsTemporary: isTemporary}
 	}
 	defer _C_freeaddrinfo(res)
 
-	if res != nil {
-		cname = _C_GoString(*_C_ai_canonname(res))
-		if cname == "" {
-			cname = name
-		}
-		if len(cname) > 0 && cname[len(cname)-1] != '.' {
-			cname += "."
-		}
-	}
 	for r := res; r != nil; r = *_C_ai_next(r) {
 		// We only asked for SOCK_STREAM, but check anyhow.
 		if *_C_ai_socktype(r) != _C_SOCK_STREAM {
@@ -204,17 +194,17 @@ func cgoLookupIPCNAME(network, name string) (addrs []IPAddr, cname string, err e
 			addrs = append(addrs, addr)
 		}
 	}
-	return addrs, cname, nil
+	return addrs, nil
 }
 
 func cgoIPLookup(result chan<- ipLookupResult, network, name string) {
-	addrs, cname, err := cgoLookupIPCNAME(network, name)
-	result <- ipLookupResult{addrs, cname, err}
+	addrs, err := cgoLookupHostIP(network, name)
+	result <- ipLookupResult{addrs, err}
 }
 
 func cgoLookupIP(ctx context.Context, network, name string) (addrs []IPAddr, err error, completed bool) {
 	if ctx.Done() == nil {
-		addrs, _, err = cgoLookupIPCNAME(network, name)
+		addrs, err = cgoLookupHostIP(network, name)
 		return addrs, err, true
 	}
 	result := make(chan ipLookupResult, 1)
diff --git a/src/net/cgo_unix_cgo.go b/src/net/cgo_unix_cgo.go
index 97427e695d..69876a675a 100644
--- a/src/net/cgo_unix_cgo.go
+++ b/src/net/cgo_unix_cgo.go
@@ -55,7 +55,6 @@ func _C_malloc(n uintptr) unsafe.Pointer { return C.malloc(C.size_t(n)) }
 func _C_free(p unsafe.Pointer)           { C.free(p) }
 
 func _C_ai_addr(ai *_C_struct_addrinfo) **_C_struct_sockaddr { return &ai.ai_addr }
-func _C_ai_canonname(ai *_C_struct_addrinfo) **_C_char       { return &ai.ai_canonname }
 func _C_ai_family(ai *_C_struct_addrinfo) *_C_int            { return &ai.ai_family }
 func _C_ai_flags(ai *_C_struct_addrinfo) *_C_int             { return &ai.ai_flags }
 func _C_ai_next(ai *_C_struct_addrinfo) **_C_struct_addrinfo { return &ai.ai_next }
diff --git a/src/net/cgo_unix_syscall.go b/src/net/cgo_unix_syscall.go
index 0d20a52464..0f643a021d 100644
--- a/src/net/cgo_unix_syscall.go
+++ b/src/net/cgo_unix_syscall.go
@@ -59,7 +59,6 @@ func _C_malloc(n uintptr) unsafe.Pointer {
 }
 
 func _C_ai_addr(ai *_C_struct_addrinfo) **_C_struct_sockaddr { return &ai.Addr }
-func _C_ai_canonname(ai *_C_struct_addrinfo) **_C_char       { return &ai.Canonname }
 func _C_ai_family(ai *_C_struct_addrinfo) *_C_int            { return &ai.Family }
 func _C_ai_flags(ai *_C_struct_addrinfo) *_C_int             { return &ai.Flags }
 func _C_ai_next(ai *_C_struct_addrinfo) **_C_struct_addrinfo { return &ai.Next }