[PATCH iproute2-next v2 4/9] ipaddress: Improve print_linkinfo()

[Serhey Popovych]

There are few places to improve:

  1) return -1 when entry is filtered instead of zero, which means
     accept entry: ipaddress_list_flush_or_save() the only user of this

  2) use ll_idx_n2a() as last resort to translate name to index for
     "should never happen" cases when cache shouldn't be considered

  3) replace open coded access to IFLA_IFNAME attribute data by
     RTA_DATA() with rta_getattr_str()

  4) simplify ifname printing since name is never NULL, thanks to (2).

Signed-off-by: Serhey Popovych <serhe.popov...@gmail.com>
---
 ip/ipaddress.c |   30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 6b8295d..6ada993 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -778,14 +778,14 @@ int print_linkinfo_brief(const struct sockaddr_nl *who,
        parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
        if (tb[IFLA_IFNAME] == NULL) {
                fprintf(stderr, "BUG: device with ifindex %d has nil ifname\n", 
ifi->ifi_index);
-               name = "<nil>";
+               name = ll_idx_n2a(ifi->ifi_index);
        } else {
                name = rta_getattr_str(tb[IFLA_IFNAME]);
        }
 
        if (filter.label &&
            (!filter.family || filter.family == AF_PACKET) &&
-           fnmatch(filter.label, RTA_DATA(tb[IFLA_IFNAME]), 0))
+           fnmatch(filter.label, name, 0))
                return -1;
 
        if (tb[IFLA_GROUP]) {
@@ -887,6 +887,7 @@ int print_linkinfo(const struct sockaddr_nl *who,
        struct ifinfomsg *ifi = NLMSG_DATA(n);
        struct rtattr *tb[IFLA_MAX+1];
        int len = n->nlmsg_len;
+       const char *name;
        unsigned int m_flag = 0;
 
        if (n->nlmsg_type != RTM_NEWLINK && n->nlmsg_type != RTM_DELLINK)
@@ -897,18 +898,22 @@ int print_linkinfo(const struct sockaddr_nl *who,
                return -1;
 
        if (filter.ifindex && ifi->ifi_index != filter.ifindex)
-               return 0;
+               return -1;
        if (filter.up && !(ifi->ifi_flags&IFF_UP))
-               return 0;
+               return -1;
 
        parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
-       if (tb[IFLA_IFNAME] == NULL)
+       if (tb[IFLA_IFNAME] == NULL) {
                fprintf(stderr, "BUG: device with ifindex %d has nil ifname\n", 
ifi->ifi_index);
+               name = ll_idx_n2a(ifi->ifi_index);
+       } else {
+               name = rta_getattr_str(tb[IFLA_IFNAME]);
+       }
 
        if (filter.label &&
            (!filter.family || filter.family == AF_PACKET) &&
-           fnmatch(filter.label, RTA_DATA(tb[IFLA_IFNAME]), 0))
-               return 0;
+           fnmatch(filter.label, name, 0))
+               return -1;
 
        if (tb[IFLA_GROUP]) {
                int group = rta_getattr_u32(tb[IFLA_GROUP]);
@@ -935,16 +940,7 @@ int print_linkinfo(const struct sockaddr_nl *who,
                print_bool(PRINT_ANY, "deleted", "Deleted ", true);
 
        print_int(PRINT_ANY, "ifindex", "%d: ", ifi->ifi_index);
-       if (tb[IFLA_IFNAME]) {
-               print_color_string(PRINT_ANY,
-                                  COLOR_IFNAME,
-                                  "ifname", "%s",
-                                  rta_getattr_str(tb[IFLA_IFNAME]));
-       } else {
-               print_null(PRINT_JSON, "ifname", NULL, NULL);
-               print_color_null(PRINT_FP, COLOR_IFNAME,
-                                "ifname", "%s", "<nil>");
-       }
+       print_color_string(PRINT_ANY, COLOR_IFNAME, "ifname", "%s", name);
 
        if (tb[IFLA_LINK]) {
                int iflink = rta_getattr_u32(tb[IFLA_LINK]);
-- 
1.7.10.4