Re: [PATCH] grub-probe -t prefix, fix update-grub_lib for Cygwin

[Christian Franke <Christian.Franke@t-online.de>]

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Robert Millan wrote:
> On Sun, Jul 20, 2008 at 02:40:14PM +0200, Christian Franke wrote:
>   
>> The shell function make_system_path_relative_to_its_root() does not work 
>> on Cygwin due to path mapping (e.g. /boot/grub/ is actually 
>> /cygwin/boot/grub).
>>
>> This patch adds '-t prefix' to grub-probe. It prints result from 
>> grub_get_prefix() which is already extended for Cygwin (svn rev 1584).
>> The result is used in make_system_path_relative_to_its_root(). This 
>> keeps the platform dependent code in getroot.c.
>>
>> Christian
>>
>> 2008-07-20	Christian Franke  <franke@computer.org>
>>
>> 	* util/grub-probe.c (enum): Add PRINT PREFIX.
>> 	(probe): Add PRINT_PREFIX, prints result of
>> 	grub_get_prefix ().
>> 	(usage): Add `prefix' to `-t' usage text.
>> 	Add some '\n' to avoid excess long lines.
>> 	(main): Add check for `-t prefix' option.
>>     
>
> This is different than the usual grub-probe usage in that it doesn't operate
> on a device.  Perhaps it would make sense to add the functionality you want in
> a separate utility?
>
> I have an increasing feeling that grub-probe is becoming bloated (though I
> admit, this is mostly my fault)
>
>   

Here is a version with works without grub-probe.

Christian


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diff --git a/util/update-grub_lib.in b/util/update-grub_lib.in
index 03a96ce..9d0f0c6 100644
--- a/util/update-grub_lib.in
+++ b/util/update-grub_lib.in
@@ -68,7 +68,22 @@ make_system_path_relative_to_its_root ()
     dir=""
   fi
 
-  echo $path | sed -e "s,^$dir,,g"
+  # XXX: This fails if $dir contains ','.
+  path=`echo "$path" | sed -e "s,^$dir,,g"` || return 1
+
+  case "`uname 2>/dev/null`" in
+    CYGWIN*)
+      # Cygwin: Check if regular or emulated mount.
+      if [ -z "$dir" ] || [ "`stat -c %D "$dir/.."`" != 620000 ] ; then
+        # Reached some mount point not below /cygdrive.
+        # GRUB does not know Cygwin's emulated mounts,
+        # convert to Win32 path and remove drive letter.
+        path=`cygpath -m "$path" | sed -n 's,^[A-Za-z]:,,p'`
+        test ! -z "$path" || return 1
+      fi ;;
+  esac
+
+  echo "$path"
 }
 
 is_path_readable_by_grub ()