[nozzle] cleanup and document nozzle_del_ip

Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>

libnozzle/libnozzle.c

@@ -1080,23 +1080,34 @@ int nozzle_add_ip(nozzle_t nozzle, const char *ip_addr, const char *prefix, char
 
 int nozzle_del_ip(nozzle_t nozzle, const char *ip_addr, const char *prefix, char **error_string)
 {
-	int err = 0, found;
+	int err = 0, savederrno = 0;
+        int found = 0;
 	struct _ip *ip = NULL, *ip_prev = NULL;
 
-	pthread_mutex_lock(&lib_mutex);
+	if ((!nozzle) || (!ip_addr) || (!prefix) || (!error_string)) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	savederrno = pthread_mutex_lock(&lib_mutex);
+	if (savederrno) {
+		errno = savederrno;
+		return -1;
+	}
 
-	if ((!_check(nozzle)) || (!ip_addr) || (!prefix) || (!error_string)) {
+	if (!_check(nozzle)) {
 		errno = EINVAL;
 		err = -1;
 		goto out_clean;
 	}
 
 	found = _find_ip(nozzle, ip_addr, prefix, &ip, &ip_prev);
-	if (!found)
+	if (!found) {
 		goto out_clean;
+	}
 
 	err = _set_ip(nozzle, "del", ip_addr, prefix, error_string, 0);
-
+	savederrno = errno;
 	if (!err) {
 		if (ip == ip_prev) {
 			nozzle->ip = ip->next;
@@ -1108,7 +1119,7 @@ int nozzle_del_ip(nozzle_t nozzle, const char *ip_addr, const char *prefix, char
 
 out_clean:
 	pthread_mutex_unlock(&lib_mutex);
-
+	errno = savederrno;
 	return err;
 }
 

libnozzle/libnozzle.h

@@ -149,6 +149,27 @@ int nozzle_set_down(nozzle_t nozzle, char **error_down, char **error_postdown);
  */
 
 int nozzle_add_ip(nozzle_t nozzle, const char *ip_addr, const char *prefix, char **error_string);
+
+/**
+ * nozzle_del_ip
+ * @brief equivalent of ip addr del or ifconfig del <ipaddress/prefix>
+ *
+ * nozzle - pointer to the nozzle struct
+ *
+ * ip_addr - string containing either an IPv4 or an IPv6 address.
+ *
+ * prefix - 24, 64 or any valid network prefix for the requested address.
+ *
+ * error_string - pointers to string to record errors from ipaddr2 (Linux) or ifconfig (BSD).
+ *                The string is malloc'ed, the caller needs to free this buffer.
+ *
+ * @return
+ * 0 on success
+ * -1 on error and error is set.
+ *  error_string is set to NULL on success
+ *  error_string will contain a string recording the execution error.
+ */
+
 int nozzle_del_ip(nozzle_t nozzle, const char *ip_addr, const char *prefix, char **error_string);
 int nozzle_get_ips(const nozzle_t nozzle, char **ip_addr_list, int *entries);