[PATCH ethtool-next 2/5] pause: add --json support

[Jakub Kicinski]

No change in normal text output:

 # ./ethtool  -a eth0
Pause parameters for eth0:
Autonegotiate:  on
RX:             on
TX:             on
RX negotiated: on
TX negotiated: on

JSON:

 # ./ethtool --json -a eth0
[ {
        "ifname": "eth0",
        "autonegotiate": true,
        "rx": true,
        "tx": true,
        "negotiated": {
            "rx": true,
            "tx": true
        }
    } ]

Signed-off-by: Jakub Kicinski <k...@kernel.org>
---
 netlink/netlink.h | 12 ++++++++++--
 netlink/pause.c   | 45 +++++++++++++++++++++++++++++++++++----------
 2 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/netlink/netlink.h b/netlink/netlink.h
index dd4a02bcc916..4916d25ed5c0 100644
--- a/netlink/netlink.h
+++ b/netlink/netlink.h
@@ -106,9 +106,17 @@ static inline const char *u8_to_bool(const struct nlattr 
*attr)
                return "n/a";
 }
 
-static inline void show_bool(const struct nlattr *attr, const char *label)
+static inline void show_bool(const char *key, const char *fmt,
+                            const struct nlattr *attr)
 {
-       printf("%s%s\n", label, u8_to_bool(attr));
+       if (is_json_context()) {
+               if (attr) {
+                       print_bool(PRINT_JSON, key, NULL,
+                                  mnl_attr_get_u8(attr));
+               }
+       } else {
+               print_string(PRINT_FP, NULL, fmt, u8_to_bool(attr));
+       }
 }
 
 /* misc */
diff --git a/netlink/pause.c b/netlink/pause.c
index 7b6b3a1d2c10..30ecdccb15eb 100644
--- a/netlink/pause.c
+++ b/netlink/pause.c
@@ -72,8 +72,16 @@ static int pause_autoneg_cb(const struct nlmsghdr *nlhdr, 
void *data)
                else if (peer.pause)
                        tx_status = true;
        }
-       printf("RX negotiated: %s\nTX negotiated: %s\n",
-              rx_status ? "on" : "off", tx_status ? "on" : "off");
+
+       if (is_json_context()) {
+               open_json_object("negotiated");
+               print_bool(PRINT_JSON, "rx", NULL, rx_status);
+               print_bool(PRINT_JSON, "tx", NULL, tx_status);
+               close_json_object();
+       } else {
+               printf("RX negotiated: %s\nTX negotiated: %s\n",
+                      rx_status ? "on" : "off", tx_status ? "on" : "off");
+       }
 
        return MNL_CB_OK;
 }
@@ -121,21 +129,34 @@ int pause_reply_cb(const struct nlmsghdr *nlhdr, void 
*data)
                return err_ret;
 
        if (silent)
-               putchar('\n');
-       printf("Pause parameters for %s:\n", nlctx->devname);
-       show_bool(tb[ETHTOOL_A_PAUSE_AUTONEG], "Autonegotiate:\t");
-       show_bool(tb[ETHTOOL_A_PAUSE_RX], "RX:\t\t");
-       show_bool(tb[ETHTOOL_A_PAUSE_TX], "TX:\t\t");
+               print_nl();
+
+       open_json_object(NULL);
+
+       print_string(PRINT_ANY, "ifname", "Pause parameters for %s:\n",
+                    nlctx->devname);
+
+       show_bool("autonegotiate", "Autonegotiate:\t%s\n",
+                 tb[ETHTOOL_A_PAUSE_AUTONEG]);
+       show_bool("rx", "RX:\t\t%s\n", tb[ETHTOOL_A_PAUSE_RX]);
+       show_bool("tx", "TX:\t\t%s\n", tb[ETHTOOL_A_PAUSE_TX]);
+
        if (!nlctx->is_monitor && tb[ETHTOOL_A_PAUSE_AUTONEG] &&
            mnl_attr_get_u8(tb[ETHTOOL_A_PAUSE_AUTONEG])) {
                ret = show_pause_autoneg_status(nlctx);
                if (ret < 0)
-                       return err_ret;
+                       goto err_close_dev;
        }
        if (!silent)
-               putchar('\n');
+               print_nl();
+
+       close_json_object();
 
        return MNL_CB_OK;
+
+err_close_dev:
+       close_json_object();
+       return err_ret;
 }
 
 int nl_gpause(struct cmd_context *ctx)
@@ -156,7 +177,11 @@ int nl_gpause(struct cmd_context *ctx)
                                      ETHTOOL_A_PAUSE_HEADER, 0);
        if (ret < 0)
                return ret;
-       return nlsock_send_get_request(nlsk, pause_reply_cb);
+
+       new_json_obj(ctx->json);
+       ret = nlsock_send_get_request(nlsk, pause_reply_cb);
+       delete_json_obj();
+       return ret;
 }
 
 /* PAUSE_SET */
-- 
2.26.2