tools/hv: reduce resource usage in hv_kvp_daemon

hv_kvp_daemon uses popen(3) and system(3) as convinience helper to
launch external helpers. These helpers are invoked via a
temporary shell process. There is no need to keep this temporary
process around while the helper runs. Replace this temporary shell
with the actual helper process via 'exec'.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Link: https://lore.kernel.org/linux-hyperv/20241202123520.27812-1-olaf@aepfle.de/
Signed-off-by: Wei Liu <wei.liu@kernel.org>

diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 296a7a62c54d37a1c5d56019f1d3e4281100f0e8..04ba035d67e9de2aed2994a73562dadce3755335 100644 (file)
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -725,7 +725,7 @@ static void kvp_get_ipconfig_info(char *if_name,
         * .
         */
 
-       sprintf(cmd, KVP_SCRIPTS_PATH "%s %s", "hv_get_dns_info", if_name);
+       sprintf(cmd, "exec %s %s", KVP_SCRIPTS_PATH "hv_get_dns_info", if_name);
 
        /*
         * Execute the command to gather DNS info.
@@ -742,7 +742,7 @@ static void kvp_get_ipconfig_info(char *if_name,
         * Enabled: DHCP enabled.
         */
 
-       sprintf(cmd, KVP_SCRIPTS_PATH "%s %s", "hv_get_dhcp_info", if_name);
+       sprintf(cmd, "exec %s %s", KVP_SCRIPTS_PATH "hv_get_dhcp_info", if_name);
 
        file = popen(cmd, "r");
        if (file == NULL)
@@ -1606,8 +1606,9 @@ static int kvp_set_ip_info(char *if_name, struct hv_kvp_ipaddr_value *new_val)
         * invoke the external script to do its magic.
         */
 
-       str_len = snprintf(cmd, sizeof(cmd), KVP_SCRIPTS_PATH "%s %s %s",
-                          "hv_set_ifconfig", if_filename, nm_filename);
+       str_len = snprintf(cmd, sizeof(cmd), "exec %s %s %s",
+                          KVP_SCRIPTS_PATH "hv_set_ifconfig",
+                          if_filename, nm_filename);
        /*
         * This is a little overcautious, but it's necessary to suppress some
         * false warnings from gcc 8.0.1.