Libguestfs - Apr 2018 - [PATCH] v2v: linux: correctly update resume=/dev/device entries (RHBZ#1532224)

When updating the device names to the new names, handle GRUB_CMDLINE
entries (typically in grub2 configuration files) correctly: loop over
the whole configuration value, and replace each occurrency of
resume=/dev/device found.

The actual code is moved away from replace_if_device, since this
function now does only the actual replacement of the device string.
---
 v2v/convert_linux.ml | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/v2v/convert_linux.ml b/v2v/convert_linux.ml
index b273785e6..02dc2fee2 100644
--- a/v2v/convert_linux.ml
+++ b/v2v/convert_linux.ml
@@ -976,7 +976,7 @@ let convert (g : G.guestfs) inspect source output rcaps     
List.flatten (List.map Array.to_list (List.map g#aug_match paths)) in
 
     (* Map device names for each entry. *)
-    let rex_resume = PCRE.compile "^(.*resume=)(/dev/\\S+)(.*)$"
+    let rex_resume = PCRE.compile "^resume=(/dev/[a-z\\d]+)(.*)$"
     and rex_device_cciss = PCRE.compile
"^/dev/(cciss/c\\d+d\\d+)(?:p(\\d+))?$"
     and rex_device = PCRE.compile "^/dev/([a-z]+)(\\d*)?$" in
 
@@ -994,18 +994,7 @@ let convert (g : G.guestfs) inspect source output rcaps    
device
       in
 
-      if String.find path "GRUB_CMDLINE" >= 0 then (
-        (* Handle grub2 resume=<dev> specially. *)
-        if PCRE.matches rex_resume value then (
-          let start = PCRE.sub 1
-          and device = PCRE.sub 2
-          and end_ = PCRE.sub 3 in
-          let device = replace_if_device path device in
-          start ^ device ^ end_
-        )
-        else value
-      )
-      else if PCRE.matches rex_device_cciss value then (
+      if PCRE.matches rex_device_cciss value then (
         let device = PCRE.sub 1
         and part = try PCRE.sub 2 with Not_found -> "" in
         "/dev/" ^ replace device ^ part
@@ -1023,7 +1012,28 @@ let convert (g : G.guestfs) inspect source output rcaps  
List.iter (
       fun path ->
         let value = g#aug_get path in
-        let new_value = replace_if_device path value in
+        let new_value +          if String.find path "GRUB_CMDLINE"
>= 0 then (
+            (* Handle grub2 resume=<dev> specially. *)
+            let rec loop str +              let index = String.find str
"resume=" in
+              if index >= 0 then (
+                let part = String.sub str index (String.length str - index) in
+                if PCRE.matches rex_resume part then (
+                  let start = String.sub str 0 (index + 7 (*
"resume=" *))
+                  and device = PCRE.sub 1
+                  and end_ = PCRE.sub 2 in
+                  let device = replace_if_device path device in
+                  start ^ device ^ loop end_
+                )
+                else str
+              )
+              else str
+            in
+            loop value
+          )
+          else
+            replace_if_device path value in
 
         if value <> new_value then (
           g#aug_set path new_value;
-- 
2.14.3

On Wed, Apr 11, 2018 at 06:15:28PM +0200, Pino Toscano
wrote:
> When updating the device names to the new names, handle GRUB_CMDLINE
> entries (typically in grub2 configuration files) correctly: loop over
> the whole configuration value, and replace each occurrency of
> resume=/dev/device found.
> 
> The actual code is moved away from replace_if_device, since this
> function now does only the actual replacement of the device string.
> ---
>  v2v/convert_linux.ml | 38 ++++++++++++++++++++++++--------------
>  1 file changed, 24 insertions(+), 14 deletions(-)
> 
> diff --git a/v2v/convert_linux.ml b/v2v/convert_linux.ml
> index b273785e6..02dc2fee2 100644
> --- a/v2v/convert_linux.ml
> +++ b/v2v/convert_linux.ml
> @@ -976,7 +976,7 @@ let convert (g : G.guestfs) inspect source output rcaps
>        List.flatten (List.map Array.to_list (List.map g#aug_match paths))
in
>  
>      (* Map device names for each entry. *)
> -    let rex_resume = PCRE.compile "^(.*resume=)(/dev/\\S+)(.*)$"
> +    let rex_resume = PCRE.compile
"^resume=(/dev/[a-z\\d]+)(.*)$"
>      and rex_device_cciss = PCRE.compile
"^/dev/(cciss/c\\d+d\\d+)(?:p(\\d+))?$"
>      and rex_device = PCRE.compile "^/dev/([a-z]+)(\\d*)?$" in
>  
> @@ -994,18 +994,7 @@ let convert (g : G.guestfs) inspect source output
rcaps >            device
>        in
>  
> -      if String.find path "GRUB_CMDLINE" >= 0 then (
> -        (* Handle grub2 resume=<dev> specially. *)
> -        if PCRE.matches rex_resume value then (
> -          let start = PCRE.sub 1
> -          and device = PCRE.sub 2
> -          and end_ = PCRE.sub 3 in
> -          let device = replace_if_device path device in
> -          start ^ device ^ end_
> -        )
> -        else value
> -      )
> -      else if PCRE.matches rex_device_cciss value then (
> +      if PCRE.matches rex_device_cciss value then (
>          let device = PCRE.sub 1
>          and part = try PCRE.sub 2 with Not_found -> "" in
>          "/dev/" ^ replace device ^ part
> @@ -1023,7 +1012,28 @@ let convert (g : G.guestfs) inspect source output
rcaps >      List.iter (
>        fun path ->
>          let value = g#aug_get path in
> -        let new_value = replace_if_device path value in
> +        let new_value > +          if String.find path
"GRUB_CMDLINE" >= 0 then (
> +            (* Handle grub2 resume=<dev> specially. *)
> +            let rec loop str > +              let index = String.find
str "resume=" in
> +              if index >= 0 then (
> +                let part = String.sub str index (String.length str -
index) in
> +                if PCRE.matches rex_resume part then (
> +                  let start = String.sub str 0 (index + 7 (*
"resume=" *))
> +                  and device = PCRE.sub 1
> +                  and end_ = PCRE.sub 2 in
> +                  let device = replace_if_device path device in
> +                  start ^ device ^ loop end_
> +                )
> +                else str
> +              )
> +              else str
> +            in
> +            loop value
> +          )
> +          else
> +            replace_if_device path value in
>  
>          if value <> new_value then (
>            g#aug_set path new_value;
Looks OK, ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.
http://people.redhat.com/~rjones/virt-df/