Rework the kernel environment subsystem. We now convert the static

environment needed at boot time to a dynamic subsystem when VM is
up.  The dynamic kernel environment is protected by an sx lock.

This adds some new functions to manipulate the kernel environment :
freeenv(), setenv(), unsetenv() and testenv().  freeenv() has to be
called after every getenv() when you have finished using the string.
testenv() only tests if an environment variable is present, and
doesn't require a freeenv() call. setenv() and unsetenv() are self
explanatory.

The kenv(2) syscall exports these new functionalities to userland,
mainly for kenv(1).

Reviewed by:	peter

1 files changed, 8 insertions, 3 deletions

diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index 2e5360a5..20d9b90 100644
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -102,7 +102,8 @@ dev_t		rootdev = NODEV;
 void
 vfs_mountroot(void *foo __unused)
 {
-	int		i;
+	char		*cp;
+	int		i, error;
 	
 	/* 
 	 * The root filesystem information is compiled in, and we are
@@ -139,8 +140,12 @@ vfs_mountroot(void *foo __unused)
 	 * supplied via some other means.  This is the preferred 
 	 * mechanism.
 	 */
-	if (!vfs_mountroot_try(getenv("vfs.root.mountfrom")))
-		return;
+	if ((cp = getenv("vfs.root.mountfrom")) != NULL) {
+		error = vfs_mountroot_try(cp);
+		freeenv(cp);
+		if (!error)
+			return;
+	}
 
 	/* 
 	 * Try values that may have been computed by the machine-dependant