[PATCH hurd 4/4] libnetfs: fix unused result from asprintf

[dnietoc]

From: Diego Nieto Cid <dnie...@gmail.com>

    ../../libnetfs/dir-lookup.c: In function 'netfs_S_dir_lookup':
    ../../libnetfs/dir-lookup.c:304:19: warning: ignoring return value of 
'asprintf' declared with attribute 'warn_unused_result' [-Wunused-result]
      304 |                   asprintf (&complete_path, "%s/%s", 
dircred->po->path,
          |                   
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      305 |                             translator_path);
          |                             ~~~~~~~~~~~~~~~~
    ../../libnetfs/dir-lookup.c:479:11: warning: ignoring return value of 
'asprintf' declared with attribute 'warn_unused_result' [-Wunused-result]
      479 |           asprintf (&newpi->po->path, "%s/%s", dircred->po->path, 
relpath);
          |           
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
---
 libnetfs/dir-lookup.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/libnetfs/dir-lookup.c b/libnetfs/dir-lookup.c
index 97732a4e..58caf015 100644
--- a/libnetfs/dir-lookup.c
+++ b/libnetfs/dir-lookup.c
@@ -301,8 +301,18 @@ netfs_S_dir_lookup (struct protid *dircred,
                  /* dircred is the root directory.  */
                  complete_path = translator_path;
                else
-                 asprintf (&complete_path, "%s/%s", dircred->po->path,
-                           translator_path);
+                 {
+                     /* Reuse the err variable. In case asprintf succeeds, it 
is
+                      * immediately ovewritten when the current block exits.
+                      */
+                     err = asprintf (&complete_path, "%s/%s", 
dircred->po->path,
+                                     translator_path);
+                     if (err == -1)
+                       {
+                         err = errno;
+                         goto out;
+                       }
+                 }
 
                 notify_port = newpi->pi.bucket->notify_port;
                 err = fshelp_set_active_translator (notify_port,
@@ -476,7 +486,10 @@ netfs_S_dir_lookup (struct protid *dircred,
       else
        {
          newpi->po->path = NULL;
-         asprintf (&newpi->po->path, "%s/%s", dircred->po->path, relpath);
+         int err2 = asprintf (&newpi->po->path, "%s/%s", dircred->po->path, 
relpath);
+         /* If asprintf fails set path to NULL so that the if below checks 
errno. */
+         if (err2 == -1)
+           newpi->po->path = NULL;
        }
 
       if (! newpi->po->path)
-- 
2.51.0