On Mon, Apr 6, 2020 at 3:57 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
On Mon, Apr 06, 2020 at 03:49:36PM +0530, Mishal Shah wrote:
> Fix libvirt build by taking care of NULL string handling

What build problems are you seeing without this patch ?  Our automated
CI is all working correctly and I don't think the changes make sense.

../../src/openvz/openvz_driver.c: In function 'openvzDomainMigratePrepare3Params':
../../src/util/glibcompat.h:33:26: error: '%s' directive argument is null [-Werror=format-overflow=]
   33 | # define g_strdup_printf vir_g_strdup_printf
../../src/openvz/openvz_driver.c:2152:16: note: in expansion of macro 'g_strdup_printf'
 2152 |     *uri_out = g_strdup_printf("ssh://%s", hostname);
      |                ^~~~~~~~~~~~~~~

This is the error that comes on compiling build. I'm using Ubuntu 18.04 & GCC version 9.2.1
 

> ---
>  src/openvz/openvz_driver.c | 6 +++++-
>  tests/sockettest.c         | 8 ++++++--
>  2 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/src/openvz/openvz_driver.c b/src/openvz/openvz_driver.c
> index 1a189dbbe7..46f117cd00 100644
> --- a/src/openvz/openvz_driver.c
> +++ b/src/openvz/openvz_driver.c
> @@ -2084,7 +2084,7 @@ openvzDomainMigratePrepare3Params(virConnectPtr dconn,
>      virDomainDefPtr def = NULL;
>      virDomainObjPtr vm = NULL;
>      char *my_hostname = NULL;
> -    const char *hostname = NULL;
> +    char *hostname = NULL;

This string is just a copy of anoter string, so shouldn't have
const removed IMHO.

>      virURIPtr uri = NULL;
>      int ret = -1;

> @@ -2149,6 +2149,10 @@ openvzDomainMigratePrepare3Params(virConnectPtr dconn,
>          }
>      }

> +    if (hostname == NULL) {
> +        goto error;
> +    }

I don't think this is right either - what's missing is that in the
previous  if() block we should have a  "hostname = my_hostname;"
assignment.

Yes, I think this assignment should have been there, otherwise, the string hostname stays NULL and throws an error in the build.
 

>      *uri_out = g_strdup_printf("ssh://%s", hostname);

>      ret = 0;
> diff --git a/tests/sockettest.c b/tests/sockettest.c
> index 29a565de40..f0a0815b88 100644
> --- a/tests/sockettest.c
> +++ b/tests/sockettest.c
> @@ -188,8 +188,12 @@ static int testMaskNetwork(const char *addrstr,
>          return -1;

>      if (STRNEQ(networkstr, gotnet)) {
> -        VIR_FREE(gotnet);
> -        fprintf(stderr, "Expected %s, got %s\n", networkstr, gotnet);
> +        if (gotnet == NULL) {
> +            fprintf(stderr, "Expected %s, got empty string\n", networkstr);
> +        } else {
> +            fprintf(stderr, "Expected %s, got %s\n", networkstr, gotnet);
> +            VIR_FREE(gotnet);
> +        }
>          return -1;
>      }

This makese no sense either, since a few lines above we have

    if (!(gotnet = virSocketAddrFormat(&network)))
       return -1;

so it is impossible for "gotnet == NULL" to be true

Yes, but I think because VIR_FREE was called before the fprintf statement, gotnet became NULL and was throwing an error in the build.

I can make the necessary changes if required.
 


Regards,
Daniel
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