[Qemu-trivial] [PATCH] slirp: Warn about failing to parse /etc/resolv.conf

[Qemu-trivial] [PATCH] slirp: Warn about failing to parse /etc/resolv.conf

[Guillaume Subiron]

Some users may have only a link-local IPv6 in their resolv.conf. In slirp mode, DNS resolution fails with timeout.

This adds two messages to alert the user that no DNS have been found instead of just exiting without explanation.
They are kept printed until the user fixes the issue in /etc/resolv.conf.

Signed-off-by: Guillaume Subiron <maethor@subiron.org>
---
 slirp/slirp.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/slirp/slirp.c b/slirp/slirp.c
index 0e6e232..1683639 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -135,8 +135,10 @@ int get_dns_addr(struct in_addr *pdns_addr)
     }
 
     f = fopen("/etc/resolv.conf", "r");
-    if (!f)
+    if (!f) {
+        fprintf(stderr, "Unable to open /etc/resolv.conf\n");
         return -1;
+    }
 
 #ifdef DEBUG
     lprint("IP address of your DNS(s): ");
@@ -168,8 +170,10 @@ int get_dns_addr(struct in_addr *pdns_addr)
         }
     }
     fclose(f);
-    if (!found)
+    if (!found) {
+        fprintf(stderr, "No IPv4 found in /etc/resolv.conf\n");
         return -1;
+    }
     return 0;
 }
 
-- 
Guillaume

Re: [Qemu-trivial] [PATCH] slirp: Warn about failing to parse /etc/resolv.conf

[Stefan Hajnoczi]

On Fri, Mar 08, 2013 at 01:24:20PM +0100, Guillaume Subiron wrote:
> Some users may have only a link-local IPv6 in their resolv.conf. In slirp mode, DNS resolution fails with timeout.
> 
> This adds two messages to alert the user that no DNS have been found instead of just exiting without explanation.
> They are kept printed until the user fixes the issue in /etc/resolv.conf.
> 
> Signed-off-by: Guillaume Subiron <maethor@subiron.org>
> ---
>  slirp/slirp.c |    8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/slirp/slirp.c b/slirp/slirp.c
> index 0e6e232..1683639 100644
> --- a/slirp/slirp.c
> +++ b/slirp/slirp.c
> @@ -135,8 +135,10 @@ int get_dns_addr(struct in_addr *pdns_addr)
>      }
>  
>      f = fopen("/etc/resolv.conf", "r");
> -    if (!f)
> +    if (!f) {
> +        fprintf(stderr, "Unable to open /etc/resolv.conf\n");
>          return -1;
> +    }
>  
>  #ifdef DEBUG
>      lprint("IP address of your DNS(s): ");
> @@ -168,8 +170,10 @@ int get_dns_addr(struct in_addr *pdns_addr)
>          }
>      }
>      fclose(f);
> -    if (!found)
> +    if (!found) {
> +        fprintf(stderr, "No IPv4 found in /etc/resolv.conf\n");
>          return -1;
> +    }
>      return 0;
>  }

Please use error_report() like other net backends.  You can drop the
newline for error_report().

Stefan