[PATCH hurd 1/4] libdiskfs: fix warning due to unused asprintf result

[dnietoc]

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

    ../../libdiskfs/dir-lookup.c: In function 'diskfs_S_dir_lookup':
    ../../libdiskfs/dir-lookup.c:312:21: warning: ignoring return value of 
'asprintf' declared with attribute 'warn_unused_result' [-Wunused-result]
      312 |                     asprintf (&complete_path, "%s/%s", 
dircred->po->path,
          |                     
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      313 |                               translator_path);
          |                               ~~~~~~~~~~~~~~~~
    ../../libdiskfs/dir-lookup.c:537:11: warning: ignoring return value of 
'asprintf' declared with attribute 'warn_unused_result' [-Wunused-result]
      537 |           asprintf (&newpi->po->path, "%s/%s", dircred->po->path, 
relpath);
          |           
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

======================================================================

../../libdiskfs/init-startup.c: In function '_diskfs_init_completed':
../../libdiskfs/init-startup.c:233:3: warning: ignoring return value of 
'asprintf' declared with attribute 'warn_unused_result' [-Wunused-result]
  233 |   asprintf (&name,
      |   ^~~~~~~~~~~~~~~~
  234 |             "%s %s", program_invocation_short_name, diskfs_disk_name ?: 
"-");
---
 libdiskfs/dir-lookup.c   | 21 +++++++++++++++++----
 libdiskfs/init-startup.c |  6 ++++--
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/libdiskfs/dir-lookup.c b/libdiskfs/dir-lookup.c
index 32be3411..8c027795 100644
--- a/libdiskfs/dir-lookup.c
+++ b/libdiskfs/dir-lookup.c
@@ -23,6 +23,7 @@
 #include <hurd/fshelp.h>
 #include <hurd/fsys.h>
 #include <hurd/paths.h>
+#include <assert-backtrace.h>
 
 #include "priv.h"
 #include "fs_S.h"
@@ -309,9 +310,18 @@ diskfs_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,
                                                      complete_path,
@@ -534,7 +544,10 @@ diskfs_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)
diff --git a/libdiskfs/init-startup.c b/libdiskfs/init-startup.c
index 0cc7f647..e7225c22 100644
--- a/libdiskfs/init-startup.c
+++ b/libdiskfs/init-startup.c
@@ -27,6 +27,7 @@
 #include <hurd/fsys.h>
 #include <hurd/paths.h>
 #include <hurd/startup.h>
+#include <assert-backtrace.h>
 
 #include "startup_S.h"
 
@@ -230,8 +231,9 @@ _diskfs_init_completed (void)
 
   notify = ports_get_send_right (pi);
   ports_port_deref (pi);
-  asprintf (&name,
-           "%s %s", program_invocation_short_name, diskfs_disk_name ?: "-");
+  err = asprintf (&name,
+                 "%s %s", program_invocation_short_name, diskfs_disk_name ?: 
"-");
+  assert_backtrace (err != -1);
   err = startup_request_notification (init, notify,
                                      MACH_MSG_TYPE_COPY_SEND, name);
   mach_port_deallocate (mach_task_self (), notify);
-- 
2.51.0