[PATCH] tools/mfndump: Avoid deliberate NULL dereference

[PATCH] tools/mfndump: Avoid deliberate NULL dereference

[Andrew Cooper]

If we failed to open an xc interface, using xch to log an error will end in
tears.  Print to stderr instead, as we are bailing immediately later.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Coverity-id: 1191885
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Dario Faggioli <dario.faggioli@citrix.com>

---

This is why macros depending on variables in scope, particularly ones named
as simily as "ERROR", are evil.
---
 tools/misc/xen-mfndump.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/misc/xen-mfndump.c b/tools/misc/xen-mfndump.c
index 8064527..e1ea536 100644
--- a/tools/misc/xen-mfndump.c
+++ b/tools/misc/xen-mfndump.c
@@ -400,7 +400,7 @@ int main(int argc, char *argv[])
     xch = xc_interface_open(0, 0, 0);
     if ( !xch )
     {
-        ERROR("Failed to open an xc handler");
+        fprintf(stderr, "Failed to open an xc handler");
         return 1;
     }
 
-- 
1.7.10.4

Re: [PATCH] tools/mfndump: Avoid deliberate NULL dereference

[Ian Campbell]

On Wed, 2014-03-12 at 21:04 +0000, Andrew Cooper wrote:

"deliberate" doesn't seem likely. "unintentional" is more plausible

> If we failed to open an xc interface, using xch to log an error will end in
> tears.  Print to stderr instead, as we are bailing immediately later.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Coverity-id: 1191885

Acked-by: Ian Campbell <Ian.Campbell@citrix.com>

> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Dario Faggioli <dario.faggioli@citrix.com>
> 
> ---
> 
> This is why macros depending on variables in scope, particularly ones named
> as simily as "ERROR", are evil.
> ---
>  tools/misc/xen-mfndump.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/misc/xen-mfndump.c b/tools/misc/xen-mfndump.c
> index 8064527..e1ea536 100644
> --- a/tools/misc/xen-mfndump.c
> +++ b/tools/misc/xen-mfndump.c
> @@ -400,7 +400,7 @@ int main(int argc, char *argv[])
>      xch = xc_interface_open(0, 0, 0);
>      if ( !xch )
>      {
> -        ERROR("Failed to open an xc handler");
> +        fprintf(stderr, "Failed to open an xc handler");
>          return 1;
>      }
>  

[PATCH v2] tools/mfndump: Avoid unintentional NULL dereference

[Andrew Cooper]

If we failed to open an xc interface, using xch to log an error will end in
tears.  Print to stderr instead, as we are bailing immediately later.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Coverity-id: 1191885
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Dario Faggioli <dario.faggioli@citrix.com>

---

v2: Reword subject

This is why macros depending on variables in scope, particularly ones named
as simily as "ERROR", are evil.
---
 tools/misc/xen-mfndump.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/misc/xen-mfndump.c b/tools/misc/xen-mfndump.c
index 8064527..e1ea536 100644
--- a/tools/misc/xen-mfndump.c
+++ b/tools/misc/xen-mfndump.c
@@ -400,7 +400,7 @@ int main(int argc, char *argv[])
     xch = xc_interface_open(0, 0, 0);
     if ( !xch )
     {
-        ERROR("Failed to open an xc handler");
+        fprintf(stderr, "Failed to open an xc handler");
         return 1;
     }
 
-- 
1.7.10.4

Re: [PATCH v2] tools/mfndump: Avoid unintentional NULL dereference

[Dario Faggioli]

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On gio, 2014-03-13 at 11:09 +0000, Andrew Cooper wrote:
> If we failed to open an xc interface, using xch to log an error will end in
> tears.  Print to stderr instead, as we are bailing immediately later.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Coverity-id: 1191885
> Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Dario Faggioli <dario.faggioli@citrix.com>
> 
If this is not yet in, feel free to add:

Acked-by: Dario Faggioli <dario.faggioli@citrix.com>

Because, I confirm, I did unintentionally and not deliberately! :-P

> v2: Reword subject
> 
> This is why macros depending on variables in scope, particularly ones named
> as simily as "ERROR", are evil.
>
I Could not agree more!

Regards,
Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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Re: [PATCH v2] tools/mfndump: Avoid unintentional NULL dereference

[Ian Jackson]

Dario Faggioli writes ("Re: [PATCH v2] tools/mfndump: Avoid unintentional NULL dereference"):
> On gio, 2014-03-13 at 11:09 +0000, Andrew Cooper wrote:
> > If we failed to open an xc interface, using xch to log an error will end in
> > tears.  Print to stderr instead, as we are bailing immediately later.
> > 
> > Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> > Coverity-id: 1191885
> > Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
> > CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
> > CC: Dario Faggioli <dario.faggioli@citrix.com>
> > 
> If this is not yet in, feel free to add:
> 
> Acked-by: Dario Faggioli <dario.faggioli@citrix.com>

Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

Thanks everyone.

Ian.