Re: [Qemu-devel] [PATCH] linux-user: check if NETLINK_ROUTE is available

[Laurent Vivier]

Le 03/06/2016 à 10:32, Riku Voipio a écrit :
> On Thu, Jun 02, 2016 at 10:14:15PM +0200, Laurent Vivier wrote:
>> Some IFLA_* symbols can be missing in the host linux/if_link.h,
>> but as they are enums and not "#defines", check in "configure" if
>> last known  (IFLA_PROTO_DOWN) is available and if not, disable
>> management of NETLINK_ROUTE protocol.
>>
>> Signed-off-by: Laurent Vivier <address@hidden>
>> ---
>> Note:
>>    This patch must be applied on top of the series:
>>    [PATCH v2 0/3] linux-user: netlink support
> 
> Generally speaking this should be squashed to 1/3 because
> else bisecting builds may fail in between that patch and this
> patch. In this case I don't care because we are talking about
> relatively old distributions that would be affected.

Yes, that's what I thought too...

Thanks,
Laurent
> 
>>  configure            | 15 +++++++++++++++
>>  linux-user/syscall.c | 18 ++++++++++++++----
>>  2 files changed, 29 insertions(+), 4 deletions(-)
>>
>> diff --git a/configure b/configure
>> index b5aab72..294d791 100755
>> --- a/configure
>> +++ b/configure
>> @@ -4526,6 +4526,17 @@ if compile_prog "" "" ; then
>>      have_fsxattr=yes
>>  fi
>>  
>> +have_rtnetlink=no
>> +cat > $TMPC << EOF
>> +#include <linux/rtnetlink.h>
>> +int main(void) {
>> +  return IFLA_PROTO_DOWN;
>> +}
>> +EOF
>> +if compile_prog "" "" ; then
>> +    have_rtnetlink=yes
>> +fi
>> +
>>  ##########################################
>>  # End of CC checks
>>  # After here, no more $cc or $ld runs
>> @@ -5461,6 +5472,10 @@ if test "$rdma" = "yes" ; then
>>    echo "CONFIG_RDMA=y" >> $config_host_mak
>>  fi
>>  
>> +if test "$have_rtnetlink" = "yes" ; then
>> +  echo "CONFIG_RTNETLINK=y" >> $config_host_mak
>> +fi
>> +
>>  # Hold two types of flag:
>>  #   CONFIG_THREAD_SETNAME_BYTHREAD  - we've got a way of setting the name on
>>  #                                     a thread we have a handle to
>> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
>> index da48ba4..7c88d63 100644
>> --- a/linux-user/syscall.c
>> +++ b/linux-user/syscall.c
>> @@ -104,7 +104,9 @@ int __clone2(int (*fn)(void *), void *child_stack_base,
>>  #include "linux_loop.h"
>>  #include <linux/if_packet.h>
>>  #include <linux/netlink.h>
>> +#ifdef CONFIG_RTNETLINK
>>  #include <linux/rtnetlink.h>
>> +#endif
>>  #include <linux/audit.h>
>>  #include "uname.h"
>>  
>> @@ -1629,6 +1631,7 @@ static abi_long target_to_host_for_each_nlmsg(struct 
>> nlmsghdr *nlh,
>>      return 0;
>>  }
>>  
>> +#ifdef CONFIG_RTNETLINK
>>  static abi_long host_to_target_for_each_rtattr(struct rtattr *rtattr,
>>                                                 size_t len,
>>                                                 abi_long 
>> (*host_to_target_rtattr)
>> @@ -2043,6 +2046,7 @@ static abi_long target_to_host_nlmsg_route(struct 
>> nlmsghdr *nlh, size_t len)
>>  {
>>      return target_to_host_for_each_nlmsg(nlh, len, 
>> target_to_host_data_route);
>>  }
>> +#endif /* CONFIG_RTNETLINK */
>>  
>>  static abi_long host_to_target_data_audit(struct nlmsghdr *nlh)
>>  {
>> @@ -2794,6 +2798,7 @@ static TargetFdTrans target_packet_trans = {
>>      .target_to_host_addr = packet_target_to_host_sockaddr,
>>  };
>>  
>> +#ifdef CONFIG_RTNETLINK
>>  static abi_long netlink_route_target_to_host(void *buf, size_t len)
>>  {
>>      return target_to_host_nlmsg_route(buf, len);
>> @@ -2808,6 +2813,7 @@ static TargetFdTrans target_netlink_route_trans = {
>>      .target_to_host_data = netlink_route_target_to_host,
>>      .host_to_target_data = netlink_route_host_to_target,
>>  };
>> +#endif /* CONFIG_RTNETLINK */
>>  
>>  static abi_long netlink_audit_target_to_host(void *buf, size_t len)
>>  {
>> @@ -2835,10 +2841,12 @@ static abi_long do_socket(int domain, int type, int 
>> protocol)
>>          return ret;
>>      }
>>  
>> -    if (domain == PF_NETLINK &&
>> -        !(protocol == NETLINK_ROUTE ||
>> -          protocol == NETLINK_KOBJECT_UEVENT ||
>> -          protocol == NETLINK_AUDIT)) {
>> +    if (domain == PF_NETLINK && !(
>> +#ifdef CONFIG_RTNETLINK
>> +         protocol == NETLINK_ROUTE ||
>> +#endif
>> +         protocol == NETLINK_KOBJECT_UEVENT ||
>> +         protocol == NETLINK_AUDIT)) {
>>          return -EPFNOSUPPORT;
>>      }
>>  
>> @@ -2857,9 +2865,11 @@ static abi_long do_socket(int domain, int type, int 
>> protocol)
>>              fd_trans_register(ret, &target_packet_trans);
>>          } else if (domain == PF_NETLINK) {
>>              switch (protocol) {
>> +#ifdef CONFIG_RTNETLINK
>>              case NETLINK_ROUTE:
>>                  fd_trans_register(ret, &target_netlink_route_trans);
>>                  break;
>> +#endif
>>              case NETLINK_KOBJECT_UEVENT:
>>                  /* nothing to do: messages are strings */
>>                  break;
>> -- 
>> 2.5.5
>>