Merge remote-tracking branch 'origin/stable/10' into devel

1 files changed, 35 insertions, 3 deletions

diff --git a/sys/kern/kern_environment.c b/sys/kern/kern_environment.c
index ff453cb..05c4f62 100644
--- a/sys/kern/kern_environment.c
+++ b/sys/kern/kern_environment.c
@@ -210,12 +210,44 @@ done:
 	return (error);
 }
 
+/*
+ * Populate the initial kernel environment.
+ *
+ * This is called very early in MD startup, either to provide a copy of the
+ * environment obtained from a boot loader, or to provide an empty buffer into
+ * which MD code can store an initial environment using kern_setenv() calls.
+ *
+ * If the global envmode is 1, the environment is initialized from the global
+ * static_env[], regardless of the arguments passed.  This implements the env
+ * keyword described in config(5).  In this case env_pos is set to env_len,
+ * causing kern_setenv() to return -1 (if len > 0) or panic (if len == 0) until
+ * the dynamic environment is available.  The envmode and static_env variables
+ * are defined in env.c which is generated by config(8).
+ *
+ * If len is non-zero, the caller is providing an empty buffer.  The caller will
+ * subsequently use kern_setenv() to add up to len bytes of initial environment
+ * before the dynamic environment is available.
+ *
+ * If len is zero, the caller is providing a pre-loaded buffer containing
+ * environment strings.  Additional strings cannot be added until the dynamic
+ * environment is available.  The memory pointed to must remain stable at least
+ * until sysinit runs init_dynamic_kenv().  If no initial environment is
+ * available from the boot loader, passing a NULL pointer allows the static_env
+ * to be installed if it is configured.
+ */
 void
 init_static_kenv(char *buf, size_t len)
 {
-	kern_envp = buf;
-	env_len = len;
-	env_pos = 0;
+
+	if (envmode == 1) {
+		kern_envp = static_env;
+		env_len = len;
+		env_pos = len;
+	} else {
+		kern_envp = buf;
+		env_len = len;
+		env_pos = 0;
+	}
 }
 
 /*