maint: remove lint uncovered by tar's new use of manywarnings

* lib/rmt.h, lib/rtapelib.c (rmt_command, rmt_dev_name__):
Now pointer to const.
* lib/rtapelib.c (rmt_open__): Check return codes from dup2, close.
Don't mishandle the case when 'pipe' allocates file descriptor 0.
* lib/system.h (sys_reset_uid_gid): Check return codes from
setuid, setgid.
* tests/genfile.c (mkhole, exec_checkpoint):
Check return code from ftruncate.
(mkhole): Don't call fseek twice.
(exec_checkpoint): Check return code from system.
(exec_command): Check return code from pipe.

1 files changed, 13 insertions, 5 deletions

diff --git a/tests/genfile.c b/tests/genfile.c
index 8541be6..fa480ef 100644
--- a/tests/genfile.c
+++ b/tests/genfile.c
@@ -485,9 +485,11 @@ generate_files_from_list ()
 static void
 mkhole (int fd, off_t displ)
 {
-  if (lseek (fd, displ, SEEK_CUR) == -1)
+  off_t offset = lseek (fd, displ, SEEK_CUR);
+  if (offset < 0)
     error (EXIT_FAILURE, errno, "lseek");
-  ftruncate (fd, lseek (fd, 0, SEEK_CUR));
+  if (ftruncate (fd, offset) != 0)
+    error (EXIT_FAILURE, errno, "ftruncate");
 }
 
 static void
@@ -685,13 +687,18 @@ exec_checkpoint (struct action *p)
 	    error (0, errno, _("cannot open `%s'"), p->name);
 	    break;
 	  }
-	ftruncate (fd, p->size);
+	if (ftruncate (fd, p->size) != 0)
+	  {
+	    error (0, errno, _("cannot truncate `%s'"), p->name);
+	    break;
+	  }
 	close (fd);
       }
       break;
 
     case OPT_EXEC:
-      system (p->name);
+      if (system (p->name) != 0)
+	error (0, 0, _("command failed: %s"), p->name);
       break;
 
     case OPT_UNLINK:
@@ -761,7 +768,8 @@ exec_command (void)
   signal (SIGCHLD, SIG_DFL);
 #endif
 
-  pipe (fd);
+  if (pipe (fd) != 0)
+    error (EXIT_FAILURE, errno, "pipe");
 
   pid = fork ();
   if (pid == -1)