os: make Setenv update C environment variables

Fixes #1569

R=rsc, bradfitzwork
CC=golang-dev
https://golang.org/cl/4456045

2 files changed, 34 insertions, 0 deletions

diff --git a/src/pkg/runtime/cgo/util.c b/src/pkg/runtime/cgo/util.c
index 0eff19aa6d..ba6e0ca9c3 100644
--- a/src/pkg/runtime/cgo/util.c
+++ b/src/pkg/runtime/cgo/util.c
@@ -4,6 +4,8 @@
 
 #include "libcgo.h"
 
+#include <stdlib.h>
+
 /* Stub for calling malloc from Go */
 static void
 x_cgo_malloc(void *p)
@@ -49,3 +51,12 @@ xlibcgo_thread_start(ThreadStart *arg)
 }
 
 void (*libcgo_thread_start)(ThreadStart*) = xlibcgo_thread_start;
+
+/* Stub for calling setenv */
+static void
+xlibcgo_setenv(char **arg)
+{
+	setenv(arg[0], arg[1], 1);
+}
+
+void (*libcgo_setenv)(char**) = xlibcgo_setenv;
diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index 52784854fd..61faa15594 100644
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -1343,3 +1343,26 @@ runtime·setcpuprofilerate(void (*fn)(uintptr*, int32), int32 hz)
 	if(hz != 0)
 		runtime·resetcpuprofiler(hz);
 }
+
+void (*libcgo_setenv)(byte**);
+
+void
+os·setenv_c(String k, String v)
+{
+	byte *arg[2];
+
+	if(libcgo_setenv == nil)
+		return;
+
+	arg[0] = runtime·malloc(k.len + 1);
+	runtime·mcpy(arg[0], k.str, k.len);
+	arg[0][k.len] = 0;
+
+	arg[1] = runtime·malloc(v.len + 1);
+	runtime·mcpy(arg[1], v.str, v.len);
+	arg[1][v.len] = 0;
+
+	runtime·asmcgocall(libcgo_setenv, arg);
+	runtime·free(arg[0]);
+	runtime·free(arg[1]);
+}