[nozzle] cleanup and document nozzle_set_up

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

libnozzle/libnozzle.c

@@ -751,46 +751,60 @@ int nozzle_reset_mac(nozzle_t nozzle)
 
 int nozzle_set_up(nozzle_t nozzle, char **error_preup, char **error_up)
 {
-	int err = 0;
+	int err = 0, savederrno = 0;
 
-	pthread_mutex_lock(&lib_mutex);
+	if (!nozzle) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	savederrno = pthread_mutex_lock(&lib_mutex);
+	if (savederrno) {
+		errno = savederrno;
+		return -1;
+	}
 
 	if (!_check(nozzle)) {
-		errno = EINVAL;
+		savederrno = EINVAL;
 		err = -1;
 		goto out_clean;
 	}
 
 	if ((nozzle->hasupdown) && ((!error_preup) || (!error_up))) {
-		errno = EINVAL;
+		savederrno = EINVAL;
 		err = -1;
 		goto out_clean;
 	}
 
-	if (nozzle->up)
+	if (nozzle->up) {
 		goto out_clean;
+	}
 
 	memset(&nozzle->ifr, 0, sizeof(struct ifreq));
 	strncpy(nozzle->ifname, nozzle->nozzlename, IFNAMSIZ);
 
-	err=ioctl(lib_cfg.sockfd, SIOCGIFFLAGS, &nozzle->ifr);
-	if (err)
+	err = ioctl(lib_cfg.sockfd, SIOCGIFFLAGS, &nozzle->ifr);
+	if (err) {
+		savederrno = errno;
 		goto out_clean;
+	}
 
 	_exec_updown(nozzle, "pre-up.d", error_preup);
 
 	nozzle->ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
-	err=ioctl(lib_cfg.sockfd, SIOCSIFFLAGS, &nozzle->ifr);
-
-	if (err)
+	err = ioctl(lib_cfg.sockfd, SIOCSIFFLAGS, &nozzle->ifr);
+	if (err) {
+		savederrno = errno;
 		goto out_clean;
+	}
 
 	_exec_updown(nozzle, "up.d", error_up);
 
 	nozzle->up = 1;
+
 out_clean:
 	pthread_mutex_unlock(&lib_mutex);
-
+	errno = savederrno;
 	return err;
 }
 

libnozzle/libnozzle.h

@@ -77,6 +77,31 @@ nozzle_t nozzle_open(char *devname, size_t devname_size, const char *updownpath)
 
 int nozzle_close(nozzle_t nozzle, char **error_down, char **error_postdown);
 
+/**
+ * nozzle_set_up
+ * @brief equivalent of ifconfig up, executes pre-up.d up.d if configured
+ *
+ * nozzle - pointer to the nozzle struct
+ *
+ * error_preup - pointers to string to record errors from executing pre-up.d
+ *               when configured. The string is malloc'ed, the caller needs to free those
+ *               buffers.
+ *
+ * error_up - pointers to string to record errors from executing up.d
+ *            when configured. The string is malloc'ed, the caller needs to free those
+ *            buffers.
+ *
+ * @return
+ * 0 on success
+ * -1 on error and error is set.
+ * error_preup / error_up are set to NULL if execution of external scripts
+ * is sucessful
+ * error_preup / error_up will contain strings recording the execution error.
+ */
+
+int nozzle_set_up(nozzle_t nozzle, char **error_preup, char **error_up);
+int nozzle_set_down(nozzle_t nozzle, char **error_down, char **error_postdown);
+
 nozzle_t nozzle_find(char *dev, size_t dev_size);
 
 int nozzle_get_fd(const nozzle_t nozzle);
@@ -91,9 +116,6 @@ int nozzle_get_mac(const nozzle_t nozzle, char **ether_addr);
 int nozzle_set_mac(nozzle_t nozzle, const char *ether_addr);
 int nozzle_reset_mac(nozzle_t nozzle);
 
-int nozzle_set_up(nozzle_t nozzle, char **error_preup, char **error_up);
-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);
 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);