Bugfix 5238: Prevent the running image from being deleted

In order to prevent the running image from being deleted, we now get
the image name of the running system from the kernel boot path given
by /proc/cmdline.  Since the menu of names of images to delete comes
from the grub config file, this is guranteed to exactly match the grub
entry that was used to boot.

Also fix the help text for "delete system image" command.

1 files changed, 12 insertions, 14 deletions

diff --git a/scripts/vyatta-boot-image.pl b/scripts/vyatta-boot-image.pl
index c3040b4..127177d 100755
--- a/scripts/vyatta-boot-image.pl
+++ b/scripts/vyatta-boot-image.pl
@@ -286,21 +286,19 @@ sub select_by_name {
 # Returns the version string of the currently running system.
 #
 sub curVer {
-    my ($fd, $ver) = (undef, undef);
-
-    my $image_boot = `grep -e '^unionfs / unionfs.*squashfs=ro' /proc/mounts`;
-    if ($image_boot ne "") {
-	open($fd, '<', $VER_FILE) or return undef;
-	while (<$fd>) {
-	    next if (!(/^Version\s+:\s+(\S+)$/));
-	    $ver = $1;
-	    last;
-	}
-	close($fd);
-    } else {
-	$ver = $OLD_IMG_VER_STR;
+    my $vers = `awk '{print \$1}' /proc/cmdline`;
+
+    # In an image-booted system, the image name is the directory name
+    # directory under "/boot" in the pathname of the kernel we booted.
+    $vers =~ s/BOOT_IMAGE=\/boot\///;
+    $vers =~ s/\/?vmlinuz.*\n$//;
+
+    # In a non-image system, the kernel resides directly under "/boot".
+    # No second-level directory means that $vers will be null.
+    if ($vers eq "") {
+	$vers = $OLD_IMG_VER_STR;
     }
-    return $ver;
+    return $vers;
 }
 
 # Deletes all of the files belonging to the disk-based non-image