[PATCH] Clean up temporary file in hardlink mode

[Tom de Vries <tdevries@suse.de>]

Hi,

Consider an executable file with hardlinks a.out and b.out.

When running dwz once:
...
$ dwz -h a.out b.out
...
a.out and b.out are updated, and remain hardlinks to the same file.

But when running dwz once more, a.out and b.out remain unchanged, and a
temporary file b.out.#dwz#.XXXXXX is left.

This is caused by the fact that the code in function dwz that is intended to
handle unchanged hardlinks is never triggered.  It is guarded by a
"resa[n].res == 1" condition, but res->res is set to 0 at the end of function
dwz, irrespective of whether the file changed or not.

Fix this by only setting res->res to 0 if the file changed.

This makes test-case twice-multifile.sh fail, we'll deal with that in a
seperate patch.

Any comments?

Thanks,
- Tom

Clean up temporary file in hardlink mode

2021-03-02  Tom de Vries  <tdevries@suse.de>

	PR dwz/24275
	* dwz.c (dwz): Only set res->res to 0 if the file changed.
	* testsuite/dwz.tests/twice-hardlink.sh: Remove PR24275 workaround.

---
 dwz.c                                 | 11 ++++++++---
 testsuite/dwz.tests/twice-hardlink.sh |  5 -----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/dwz.c b/dwz.c
index 1d7d815..96f292d 100644
--- a/dwz.c
+++ b/dwz.c
@@ -15255,6 +15255,10 @@ remove_empty_pus (void)
 /* Helper structure for hardlink discovery.  */
 struct file_result
 {
+  /* -2: Already processed under different name.
+     -1: Ignore.
+      0: Processed, changed.
+      1: Processed, unchanged.  */
   int res;
   dev_t dev;
   ino_t ino;
@@ -15315,7 +15319,7 @@ dwz (const char *file, const char *outfile, struct file_result *res,
 			 file);
 	      close (fd);
 	      res->res = -2;
-	      return 1;
+	      return 0;
 	    }
 	  /* If it changed, try to hardlink it again.  */
 	  if (resa[n].res == 0)
@@ -15572,6 +15576,9 @@ dwz (const char *file, const char *outfile, struct file_result *res,
 
 	  if (write_dso (dso, outfile, &st, save_to_temp))
 	    ret = 1;
+	  else
+	    res->res = 0;
+
 	  if (unlikely (progress_p))
 	    report_progress ();
 	}
@@ -15595,8 +15602,6 @@ dwz (const char *file, const char *outfile, struct file_result *res,
   close (fd);
 
   free (dso);
-  if (ret == 0)
-    res->res = 0;
   if (ret == 3)
     {
       ret = (outfile != NULL) ? 1 : 0;
diff --git a/testsuite/dwz.tests/twice-hardlink.sh b/testsuite/dwz.tests/twice-hardlink.sh
index 6ce5ee1..6bc0794 100644
--- a/testsuite/dwz.tests/twice-hardlink.sh
+++ b/testsuite/dwz.tests/twice-hardlink.sh
@@ -29,8 +29,3 @@ fi
 cmp 1 1.saved
 
 rm -f 1 1.saved 2 2.saved dwz.err
-
-if [ -f 2.#dwz#.* ]; then
-    echo "PR24275 workaround used" > dwz.info
-    rm -f 2.#dwz#.*
-fi