diff --git a/ChangeLog b/ChangeLog
index 2d25269ac7..07d846dc58 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Thu Jul 10 23:51:36 2014  Naohisa Goto  <ngotogenome@gmail.com>
+
+	* hash.c (ruby_setenv): Fix TestEnv#test_aset failure on Solaris 9.
+	  When name contains '=', ruby_setenv raises Errno::EINVAL.
+	  That is the same behavior as Solaris 10.
+	  NULL check for malloc return value is also added.
+
 Thu Jul 10 15:02:55 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* vm_insnhelper.c (vm_callee_setup_keyword_arg): adjust VM stack
diff --git a/hash.c b/hash.c
index 4bf0ae3715..c600fd11ab 100644
--- a/hash.c
+++ b/hash.c
@@ -2729,6 +2729,10 @@ getenvblocksize()
 {
     return (rb_w32_osver() >= 5) ? 32767 : 5120;
 }
+#endif
+
+#if defined(_WIN32) || \
+  (defined(__sun) && !(defined(HAVE_SETENV) && defined(HAVE_UNSETENV)))
 
 NORETURN(static void invalid_envname(const char *name));
 
@@ -2798,10 +2802,22 @@ ruby_setenv(const char *name, const char *value)
 #endif
     }
 #elif defined __sun
-    size_t len;
-    char **env_ptr, *str;
+    /* Solaris 9 (or earlier) does not have setenv(3C) and unsetenv(3C). */
+    /* The below code was tested on Solaris 10 by:
+         % ./configure ac_cv_func_setenv=no ac_cv_func_unsetenv=no
+    */
+    size_t len, mem_size;
+    char **env_ptr, *str, *mem_ptr;
 
+    check_envname(name);
     len = strlen(name);
+    if (value) {
+	mem_size = len + strlen(value) + 2;
+	mem_ptr = malloc(mem_size);
+	if (mem_ptr == NULL)
+	    rb_sys_fail_str(rb_sprintf("malloc("PRIuSIZE")", mem_size));
+	snprintf(mem_ptr, mem_size, "%s=%s", name, value);
+    }
     for (env_ptr = GET_ENVIRON(environ); (str = *env_ptr) != 0; ++env_ptr) {
 	if (!strncmp(str, name, len) && str[len] == '=') {
 	    if (!in_origenv(str)) free(str);
@@ -2810,10 +2826,10 @@ ruby_setenv(const char *name, const char *value)
 	}
     }
     if (value) {
-	str = malloc(len += strlen(value) + 2);
-	snprintf(str, len, "%s=%s", name, value);
-	if (putenv(str))
+	if (putenv(mem_ptr)) {
+	    free(mem_ptr);
 	    rb_sys_fail_str(rb_sprintf("putenv(%s)", name));
+	}
     }
 #else  /* WIN32 */
     size_t len;