Fix more -t/-x discrepancies

Problem reported by Guillermo de Angel in:
https://lists.gnu.org/r/bug-tar/2026-03/msg00007.html
* THANKS: Add him, and sort.
* src/extract.c (extract_dir, extract_file):
* src/incremen.c (purge_directory):
Do not call skip_member, as the caller now does that, and does it
more reliably.
* src/extract.c (extract_file):
Mark file as skipped when we’ve read it.
(extract_archive): Always call skip_member after extracting,
as it suppresses the skip as needed.
* src/incremen.c (try_purge_directory): Remove; no longer
needed.  Move internals to purge_directory.
* src/list.c (read_header): Do not treat LNKTYPE header as having
size zero, as it can be nonzero (e.g., ‘pax -o linkdata’).
Set info->skipped field according to how the header was read.
(member_is_dir): Remove; no longer needed.
(skim_member): Skip directory data too, unless it’s already been
skipped (i.e., read).
* tests/extrac32.at: New file.
* tests/Makefile.am (TESTSUITE_AT):
* tests/testsuite.at:
Add it.
* tests/skipdir.at (skip directory members):
Fix test to match the correct behavior.
This fixes a bug introduced in commit
b009124ffd
dated 2025-05-12 17:17:21 +0300.

src/extract.c

@@ -1132,7 +1132,7 @@ safe_dir_mode (struct stat const *st)
 /* Extractor functions for various member types */
 
 static bool
-extract_dir (char *file_name, char typeflag)
+extract_dir (char *file_name, char UNNAMED (typeflag))
 {
   int status;
   mode_t mode;
@@ -1157,8 +1157,6 @@ extract_dir (char *file_name, char typeflag)
   if (incremental_option)
     /* Read the entry and delete files that aren't listed in the archive.  */
     purge_directory (file_name);
-  else if (typeflag == GNUTYPE_DUMPDIR)
-    skip_member ();
 
   mode = safe_dir_mode (&current_stat_info.stat);
 
@@ -1338,10 +1336,7 @@ extract_file (char *file_name, char typeflag)
     {
       fd = sys_exec_command (file_name, 'f', &current_stat_info);
       if (fd < 0)
-	{
-	  skip_member ();
-	  return true;
-	}
+	return true;
     }
   else
     {
@@ -1362,7 +1357,6 @@ extract_file (char *file_name, char typeflag)
 	    = maybe_recoverable (file_name, true, &interdir_made);
 	  if (recover != RECOVER_OK)
 	    {
-	      skip_member ();
 	      if (recover == RECOVER_SKIP)
 		return true;
 	      open_error (file_name);
@@ -1409,6 +1403,7 @@ extract_file (char *file_name, char typeflag)
       }
 
   skim_file (size, false);
+  current_stat_info.skipped = true;
 
   mv_end ();
 
@@ -1921,15 +1916,9 @@ extract_archive (void)
 
   tar_extractor_t fun = prepare_to_extract (current_stat_info.file_name,
 					    typeflag);
-  if (fun)
-    {
-      if (fun (current_stat_info.file_name, typeflag))
-	return;
-    }
-  else
-    skip_member ();
-
-  if (backup_option)
+  bool ok = fun && fun (current_stat_info.file_name, typeflag);
+  skip_member ();
+  if (!ok && backup_option)
     undo_last_backup ();
 }
 

src/incremen.c

@@ -1621,8 +1621,8 @@ dumpdir_ok (char *dumpdir)
 
 /* Examine the directories under directory_name and delete any
    files that were not there at the time of the back-up. */
-static bool
-try_purge_directory (char const *directory_name)
+void
+purge_directory (char const *directory_name)
 {
   char *current_dir;
   char *cur, *arc, *p;
@@ -1630,18 +1630,18 @@ try_purge_directory (char const *directory_name)
   struct dumpdir *dump;
 
   if (!is_dumpdir (&current_stat_info))
-    return false;
+    return;
 
   current_dir = tar_savedir (directory_name, false);
 
   if (!current_dir)
     /* The directory doesn't exist now.  It'll be created.  In any
        case, we don't have to delete any files out of it.  */
-    return false;
+    return;
 
   /* Verify if dump directory is sane */
   if (!dumpdir_ok (current_stat_info.dumpdir))
-    return false;
+    return;
 
   /* Process renames */
   for (arc = current_stat_info.dumpdir; *arc; arc += strlen (arc) + 1)
@@ -1661,7 +1661,7 @@ try_purge_directory (char const *directory_name)
 			quote (temp_stub));
 	      free (temp_stub);
 	      free (current_dir);
-	      return false;
+	      return;
 	    }
 	}
       else if (*arc == 'R')
@@ -1695,7 +1695,7 @@ try_purge_directory (char const *directory_name)
 	      free (current_dir);
 	      /* FIXME: Make sure purge_directory(dst) will return
 		 immediately */
-	      return false;
+	      return;
 	    }
 	}
     }
@@ -1749,14 +1749,6 @@ try_purge_directory (char const *directory_name)
   dumpdir_free (dump);
 
   free (current_dir);
-  return true;
-}
-
-void
-purge_directory (char const *directory_name)
-{
-  if (!try_purge_directory (directory_name))
-    skip_member ();
 }
 
 void

src/list.c

@@ -423,20 +423,15 @@ read_header (union block **return_block, struct tar_stat_info *info,
       if ((status = tar_checksum (header, false)) != HEADER_SUCCESS)
 	break;
 
-      /* Good block.  Decode file size and return.  */
-
-      if (header->header.typeflag == LNKTYPE)
-	info->stat.st_size = 0;	/* links 0 size on tape */
-      else
+      info->stat.st_size = OFF_FROM_HEADER (header->header.size);
+      if (info->stat.st_size < 0)
 	{
-	  info->stat.st_size = OFF_FROM_HEADER (header->header.size);
-	  if (info->stat.st_size < 0)
-	    {
-	      status = HEADER_FAILURE;
-	      break;
-	    }
+	  status = HEADER_FAILURE;
+	  break;
 	}
 
+      info->skipped = false;
+
       if (header->header.typeflag == GNUTYPE_LONGNAME
 	  || header->header.typeflag == GNUTYPE_LONGLINK
 	  || header->header.typeflag == XHDTYPE
@@ -493,11 +488,15 @@ read_header (union block **return_block, struct tar_stat_info *info,
 		}
 
 	      *bp = '\0';
+	      info->skipped = true;
 	    }
 	  else if (header->header.typeflag == XHDTYPE
 		   || header->header.typeflag == SOLARIS_XHDTYPE)
-	    xheader_read (&info->xhdr, header,
-			  OFF_FROM_HEADER (header->header.size));
+	    {
+	      xheader_read (&info->xhdr, header,
+			    OFF_FROM_HEADER (header->header.size));
+	      info->skipped = true;
+	    }
 	  else if (header->header.typeflag == XGLTYPE)
 	    {
 	      struct xheader xhdr;
@@ -511,6 +510,7 @@ read_header (union block **return_block, struct tar_stat_info *info,
 			    OFF_FROM_HEADER (header->header.size));
 	      xheader_decode_global (&xhdr);
 	      xheader_destroy (&xhdr);
+	      info->skipped = true;
 	      if (mode == read_header_x_global)
 		{
 		  status = HEADER_SUCCESS_EXTENDED;
@@ -1412,23 +1412,6 @@ skip_member (void)
   skim_member (false);
 }
 
-static bool
-member_is_dir (struct tar_stat_info *info, char typeflag)
-{
-  switch (typeflag) {
-  case AREGTYPE:
-  case REGTYPE:
-  case CONTTYPE:
-    return info->had_trailing_slash;
-
-  case DIRTYPE:
-    return true;
-
-  default:
-    return false;
-  }
-}
-
 /* Skip the current member in the archive.
    If MUST_COPY, always copy instead of skipping.  */
 void
@@ -1436,18 +1419,17 @@ skim_member (bool must_copy)
 {
   if (!current_stat_info.skipped)
     {
-      bool is_dir = member_is_dir (&current_stat_info,
-				   current_header->header.typeflag);
       set_next_block_after (current_header);
 
       mv_begin_read (&current_stat_info);
 
       if (current_stat_info.is_sparse)
 	sparse_skim_file (&current_stat_info, must_copy);
-      else if (!is_dir)
+      else
 	skim_file (current_stat_info.stat.st_size, must_copy);
 
       mv_end ();
+      current_stat_info.skipped = true;
     }
 }