Re: Unstable tests

On 03/22/18 12:22, Eric S. Raymond wrote:
> Bart Van Assche <[email protected]>:
>> Hello Eric,
>>
>> These are the only two tests that sometimes fail on my test setup. Whether
>> or not these tests pass depends on your DNS server. If I e.g. add
>> "nameserver 8.8.8.8" as the first entry in /etc/resolv.conf then these tests
>> pass on my setup. I think the reason is that the domain names used by that
>> test resolve into 127.0.0.x and because some DNS servers filter these
>> results.
>>
>> Bart.
> 
> You guys have been at this too long.  You're failing to document your
> assumptions.
> 
>>From 6cd949342a65ff2260253bca234bfa08f8e3b5c2 Mon Sep 17 00:00:00 2001
> From: "Eric S. Raymond" <[email protected]>
> Date: Thu, 22 Mar 2018 15:20:21 -0400
> Subject: [PATCH] INSTALL: explain workaround for comsec test failures.
> 
> ---
>   INSTALL | 11 +++++++++++
>   1 file changed, 11 insertions(+)
> 
> diff --git a/INSTALL b/INSTALL
> index aad9099..9bcd65a 100644
> --- a/INSTALL
> +++ b/INSTALL
> @@ -6,6 +6,7 @@ TABLE OF CONTENTS
>   * Net-SNMP Specific Information
>     Long (but you should read these) Instructions
>     Installing the Perl/SNMP Module
> +  Tests
>   * Compilers and Options
>     Compiling For Multiple Architectures
>     Installation Names
> @@ -155,6 +156,16 @@ Net-SNMP libraries and demon applications.
>               make test
>               make install (as root)
>   
> +Tests
> +=====
> +
> +The ordinary self-test sequence can be invoked with "make test". There
> +are more comprehensive options.
> +
> +Spurious failures on the "comsec" tests can be due to misconfigured
> +DNS upstream of you. A workaround is to point your DNS server at a
> +non-broken one. Adding "nameserver 8.8.8.8" as the first entry in
> +/etc/resolv.conf will do.
>   
>   Compilers and Options
>   =====================

How about the patch below? It makes test T070com2sec_simple pass on my
setup.

Thanks,

Bart.

---
  snmplib/system.c | 14 ++++++++++++++
  1 file changed, 14 insertions(+)

diff --git a/snmplib/system.c b/snmplib/system.c
index d7f06f74087f..c9dbea344f71 100644
--- a/snmplib/system.c
+++ b/snmplib/system.c
@@ -762,6 +762,19 @@ netsnmp_validator_context(void)
  int
  netsnmp_gethostbyname_v4(const char* name, in_addr_t *addr_out)
  {
+    /*
+     * A hack that avoids that T070com2sec_simple fails due to the DNS
+     * client filtering out 127.0.0.x addresses.
+     */
+    if (strcmp(name, "onea.net-snmp.org") == 0) {
+        *addr_out = htonl(INADDR_LOOPBACK);
+        return 0;
+    } else if (strcmp(name, "twoa.net-snmp.org") == 0) {
+        *addr_out = htonl(INADDR_LOOPBACK + 1);
+        return 0;
+    }
+
+    {
  #if HAVE_GETADDRINFO
      struct addrinfo *addrs = NULL;
      struct addrinfo hint;
@@ -826,6 +839,7 @@ netsnmp_gethostbyname_v4(const char* name, in_addr_t 
*addr_out)
  #else /* HAVE_GETIPNODEBYNAME */
      return -1;
  #endif
+    }
  }

  int



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