fix "iw phy#0 info"

Ben Greear reported that on a kernel that doesn't have the split
(and therefore filtered) wiphy dump feature, "iw phy#0 info" was
reporting data for all devices, rather than just one. This was a
result of using the split/filtered dump rather than a simple get
on "older" kernels (before 3.10!)

Fix this by checking the kernel feature before getting the data.

diff --git a/info.c b/info.c
index 209e882a6af954e13b7707e50f10a736d5949028..54d9a8d80ced68ed0ce1586b7b9e02ab60eccd20 100644 (file)
--- a/info.c
+++ b/info.c
@@ -531,19 +531,28 @@ broken_combination:
        return NL_SKIP;
 }
 
+static bool nl80211_has_split_wiphy = false;
+
 static int handle_info(struct nl80211_state *state,
                       struct nl_cb *cb,
                       struct nl_msg *msg,
                       int argc, char **argv,
                       enum id_input id)
 {
+       char *feat_args[] = { "features", "-q" };
+       int err;
+
+       err = handle_cmd(state, CIB_NONE, 2, feat_args);
+       if (!err && nl80211_has_split_wiphy) {
+               nla_put_flag(msg, NL80211_ATTR_SPLIT_WIPHY_DUMP);
+               nlmsg_hdr(msg)->nlmsg_flags |= NLM_F_DUMP;
+       }
+
        nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, print_phy_handler, NULL);
-       /* kernels not supporting it will ignore this */
-       nla_put_flag(msg, NL80211_ATTR_SPLIT_WIPHY_DUMP);
 
        return 0;
 }
-__COMMAND(NULL, info, "info", NULL, NL80211_CMD_GET_WIPHY, NLM_F_DUMP, 0, CIB_PHY, handle_info,
+__COMMAND(NULL, info, "info", NULL, NL80211_CMD_GET_WIPHY, 0, 0, CIB_PHY, handle_info,
         "Show capabilities for the specified wireless device.", NULL);
 TOPLEVEL(list, NULL, NL80211_CMD_GET_WIPHY, NLM_F_DUMP, CIB_NONE, handle_info,
         "List all wireless devices and their capabilities.");
@@ -566,6 +575,8 @@ static int print_feature_handler(struct nl_msg *msg, void *arg)
 {
        struct nlattr *tb_msg[NL80211_ATTR_MAX + 1];
        struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
+       bool print = (unsigned long)arg;
+#define maybe_printf(...) do { if (print) printf(__VA_ARGS__); } while (0)
 
        nla_parse(tb_msg, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
                  genlmsg_attrlen(gnlh, 0), NULL);
@@ -573,9 +584,11 @@ static int print_feature_handler(struct nl_msg *msg, void *arg)
        if (tb_msg[NL80211_ATTR_PROTOCOL_FEATURES]) {
                uint32_t feat = nla_get_u32(tb_msg[NL80211_ATTR_PROTOCOL_FEATURES]);
 
-               printf("nl80211 features: 0x%x\n", feat);
-               if (feat & NL80211_PROTOCOL_FEATURE_SPLIT_WIPHY_DUMP)
-                       printf("\t* split wiphy dump\n");
+               maybe_printf("nl80211 features: 0x%x\n", feat);
+               if (feat & NL80211_PROTOCOL_FEATURE_SPLIT_WIPHY_DUMP) {
+                       maybe_printf("\t* split wiphy dump\n");
+                       nl80211_has_split_wiphy = true;
+               }
        }
 
        return NL_SKIP;
@@ -585,9 +598,10 @@ static int handle_features(struct nl80211_state *state,
                           struct nl_cb *cb, struct nl_msg *msg,
                           int argc, char **argv, enum id_input id)
 {
-       nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, print_feature_handler, NULL);
+       unsigned long print = argc == 0 || strcmp(argv[0], "-q");
+       nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, print_feature_handler, (void *)print);
        return 0;
 }
 
-TOPLEVEL(features, NULL, NL80211_CMD_GET_PROTOCOL_FEATURES, 0, CIB_NONE,
+TOPLEVEL(features, "", NL80211_CMD_GET_PROTOCOL_FEATURES, 0, CIB_NONE,
         handle_features, "");