Description:
This bug was originally reported in [1].
We can't rely on the fact that network device names are ethX any more. If we use biosdevname Udev helper [2], then for example Ethernet devices are labeled em1, but any other name can be used generally.
MySQL reads the HW address of any non-zero ethX device to generate an UUID. When a user uses biosdevname (which is default in Fedora by the way) then my_gethwaddr() returns 00:00:00:00:00:00 now.
We can loop through all devices using SIOCGIFCONF and get their HW address. There is a comment in mysys/my_gethwaddr.c that says we can use any of non-zero devices, which is how the suggested fix works.
[1] https://bugzilla.redhat.com/show_bug.cgi?id=682365
[2] http://freecode.com/projects/biosdevname
How to repeat:
Log values returned by my_gethwaddr() when biosdevname is used.
Suggested fix:
diff -up mysql-5.5.15/mysys/my_gethwaddr.c.netdevname mysql-5.5.15/mysys/my_gethwaddr.c
--- mysql-5.5.15/mysys/my_gethwaddr.c.netdevname 2011-07-13 21:09:02.000000000 +0200
+++ mysql-5.5.15/mysys/my_gethwaddr.c 2011-11-01 12:32:35.356119715 +0100
@@ -68,28 +68,47 @@ err:
#include <sys/ioctl.h>
#include <net/ethernet.h>
+#define MAX_IFS 64
+
my_bool my_gethwaddr(uchar *to)
{
int fd, res= 1;
struct ifreq ifr;
char zero_array[ETHER_ADDR_LEN] = {0};
+ struct ifconf ifc;
+ struct ifreq ifs[MAX_IFS], *ifri, *ifend;
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0)
goto err;
- bzero(&ifr, sizeof(ifr));
- strnmov(ifr.ifr_name, "eth0", sizeof(ifr.ifr_name) - 1);
+ ifc.ifc_len = sizeof(ifs);
+ ifc.ifc_req = ifs;
+ if (ioctl(fd, SIOCGIFCONF, &ifc) < 0)
+ {
+ close(fd);
+ goto err;
+ }
+
+ memcpy(to, zero_array, ETHER_ADDR_LEN);
- do
+ ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
+ for (ifri = ifc.ifc_req; ifri < ifend; ifri++)
{
- if (ioctl(fd, SIOCGIFHWADDR, &ifr) >= 0)
+ if (ifri->ifr_addr.sa_family == AF_INET)
{
- memcpy(to, &ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
- res= memcmp(to, zero_array, ETHER_ADDR_LEN) ? 0 : 1;
+ bzero(&ifr, sizeof(ifr));
+ strncpy(ifr.ifr_name, ifri->ifr_name, sizeof(ifr.ifr_name));
+
+ /* Get HW address */
+ if (ioctl(fd, SIOCGIFHWADDR, &ifr) >= 0)
+ {
+ memcpy(to, &ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
+ if (!(res= memcmp(to, zero_array, ETHER_ADDR_LEN) ? 0 : 1))
+ break;
+ }
}
- } while (res && (errno == 0 || errno == ENODEV) && ifr.ifr_name[3]++ < '6');
-
+ }
close(fd);
err:
return res;
