[nozzle] cleanup and document nozzle_get_fd

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

libnozzle/libnozzle.c

@@ -1185,12 +1185,21 @@ int nozzle_del_ip(nozzle_t nozzle, const char *ip_addr, const char *prefix, char
 
 int nozzle_get_fd(const nozzle_t nozzle)
 {
-	int fd;
+	int fd = -1, 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 = ENOENT;
 		fd = -1;
 		goto out_clean;
 	}
@@ -1199,7 +1208,7 @@ int nozzle_get_fd(const nozzle_t nozzle)
 
 out_clean:
 	pthread_mutex_unlock(&lib_mutex);
-
+	errno = savederrno;
 	return fd;
 }
 

libnozzle/libnozzle.h

@@ -292,7 +292,7 @@ int nozzle_reset_mac(nozzle_t nozzle);
 
 /**
  * nozzle_get_handle_by_name
- * @brief fine a nozzle handle by device name
+ * @brief find a nozzle handle by device name
  *
  * devname - string containing the name of the interface
  *
@@ -305,7 +305,7 @@ nozzle_t nozzle_get_handle_by_name(char *devname);
 
 /**
  * nozzle_get_name_by_handle
- * @brief fine a nozzle handle by device name
+ * @brief retrive nozzle interface name by handle
  *
  * nozzle - pointer to the nozzle struct
  *
@@ -316,6 +316,17 @@ nozzle_t nozzle_get_handle_by_name(char *devname);
 
 const char *nozzle_get_name_by_handle(const nozzle_t nozzle);
 
+/**
+ * nozzle_get_fd
+ * @brief 
+ *
+ * nozzle - pointer to the nozzle struct
+ *
+ * @return
+ * fd associated to a given nozzle on success.
+ * -1 on error and errno is set.
+ */
+
 int nozzle_get_fd(const nozzle_t nozzle);
 
 #endif