On 07/17/2011 05:36 PM, Sasha Levin wrote:
> On Sun, 2011-07-17 at 16:56 +0800, Asias He wrote:
>> This patch get domain name and nameserver information from host config
>> file /etc/resolv.conf.
>>
>> Guest can obtain DNS information through DHCP.
>>
>> Signed-off-by: Asias He <[email protected]>
>> ---
>
> Seeing this after this patch:
>
> cc1: warnings being treated as errors
> net/uip/dhcp.c: In function 'uip_dhcp_get_dns':
> net/uip/dhcp.c:49:9: error: ignoring return value of 'fscanf', declared
> with attribute warn_unused_result
> make: *** [net/uip/dhcp.o] Error 1
Yup. We need to check the return value of 'fscanf'.
My gcc (4.6.1) does not catch this by default, I guess we need to enable
this explicitly in our Makefile.
>> tools/kvm/include/kvm/uip.h | 6 ++++++
>> tools/kvm/net/uip/dhcp.c | 34 ++++++++++++++++++++++++++++++++++
>> 2 files changed, 40 insertions(+), 0 deletions(-)
>>
>> diff --git a/tools/kvm/include/kvm/uip.h b/tools/kvm/include/kvm/uip.h
>> index 6534c7f..e645d3f 100644
>> --- a/tools/kvm/include/kvm/uip.h
>> +++ b/tools/kvm/include/kvm/uip.h
>> @@ -42,6 +42,8 @@
>> #define UIP_DHCP_OFFER 2
>> #define UIP_DHCP_REQUEST 3
>> #define UIP_DHCP_ACK 5
>> +#define UIP_DHCP_MAX_DNS_SERVER_NR 3
>> +#define UIP_DHCP_MAX_DOMAIN_NAME_LEN 256
>> #define UIP_DHCP_TAG_MSG_TYPE 53
>> #define UIP_DHCP_TAG_MSG_TYPE_LEN 1
>> /*
>> @@ -178,6 +180,8 @@ struct uip_info {
>> int buf_free_nr;
>> int buf_used_nr;
>> u32 host_ip;
>> + u32 dns_ip[UIP_DHCP_MAX_DNS_SERVER_NR];
>> + char *domain_name;
>> u32 buf_nr;
>> };
>>
>> @@ -327,4 +331,6 @@ struct uip_buf *uip_buf_clone(struct uip_tx_arg *arg);
>>
>> int uip_udp_make_pkg(struct uip_info *info, struct uip_udp_socket *sk,
>> struct uip_buf *buf, u8 *payload, int payload_len);
>> bool uip_udp_is_dhcp(struct uip_udp *udp);
>> +
>> +int uip_dhcp_get_dns(struct uip_info *info);
>> #endif /* KVM__UIP_H */
>> diff --git a/tools/kvm/net/uip/dhcp.c b/tools/kvm/net/uip/dhcp.c
>> index 0a6293a..9321cdc 100644
>> --- a/tools/kvm/net/uip/dhcp.c
>> +++ b/tools/kvm/net/uip/dhcp.c
>> @@ -1,5 +1,7 @@
>> #include "kvm/uip.h"
>>
>> +#include <arpa/inet.h>
>> +
>> static inline bool uip_dhcp_is_discovery(struct uip_dhcp *dhcp)
>> {
>> return (dhcp->option[2] == UIP_DHCP_DISCOVER &&
>> @@ -29,3 +31,35 @@ bool uip_udp_is_dhcp(struct uip_udp *udp)
>>
>> return true;
>> }
>> +
>> +int uip_dhcp_get_dns(struct uip_info *info)
>> +{
>> + char key[256], val[256];
>> + struct in_addr addr;
>> + int ret = -1;
>> + int n = 0;
>> + FILE *fp;
>> + u32 ip;
>> +
>> + fp = fopen("/etc/resolv.conf", "r");
>> + if (!fp)
>> + goto out;
>> +
>> + while (!feof(fp)) {
>> + fscanf(fp, "%s %s\n", key, val);
>> + if (strncmp("domain", key, 6) == 0)
>> + info->domain_name = strndup(val,
>> UIP_DHCP_MAX_DOMAIN_NAME_LEN);
>> + else if (strncmp("nameserver", key, 10) == 0) {
>> + if (!inet_aton(val, &addr))
>> + continue;
>> + ip = ntohl(addr.s_addr);
>> + if (n < UIP_DHCP_MAX_DNS_SERVER_NR)
>> + info->dns_ip[n++] = ip;
>> + ret = 0;
>> + }
>> + }
>> +
>> +out:
>> + fclose(fp);
>> + return ret;
>> +}
>
>
--
Best Regards,
Asias He
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