Don't open files that will be skipped

Previously, when creating an archive file with pax(1), pax will attempt
to open a file even if the file will be skipped due to an -s replacement
with the empty string. With this change, pax will not attempt to open
files that it knows will be skipped.

When doing direct copies to a directory (-rw), pax already skips
the file before attempting to open it. So this makes the behavior
more consistent.

This can measurably speed up pax when skipping a large number of files.

OK tb@

diff --git a/bin/pax/ar_subs.c b/bin/pax/ar_subs.c
index a8bdc86..c542aa6 100644 (file)
--- a/bin/pax/ar_subs.c
+++ b/bin/pax/ar_subs.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ar_subs.c,v 1.50 2021/10/24 21:24:21 deraadt Exp $    */
+/*     $OpenBSD: ar_subs.c,v 1.51 2023/07/10 16:28:33 jeremy Exp $     */
 /*     $NetBSD: ar_subs.c,v 1.5 1995/03/21 09:07:06 cgd Exp $  */
 
 /*-
@@ -441,6 +441,23 @@ wr_archive(ARCHD *arcn, int is_app)
                if (hlk && (chk_lnk(arcn) < 0))
                        break;
 
+               /*
+                * Modify the name as requested by the user
+                */
+               if ((res = mod_name(arcn)) < 0) {
+                       /*
+                        * pax finished, purge link table entry and stop
+                        */
+                       purg_lnk(arcn);
+                       break;
+               } else if (res > 0) {
+                       /*
+                        * skipping file, purge link table entry
+                        */
+                       purg_lnk(arcn);
+                       continue;
+               }
+
                if (PAX_IS_REG(arcn->type) || (arcn->type == PAX_HRG)) {
                        /*
                         * we will have to read this file. by opening it now we
@@ -456,20 +473,7 @@ wr_archive(ARCHD *arcn, int is_app)
                        }
                }
 
-               /*
-                * Now modify the name as requested by the user
-                */
-               if ((res = mod_name(arcn)) < 0) {
-                       /*
-                        * name modification says to skip this file, close the
-                        * file and purge link table entry
-                        */
-                       rdfile_close(arcn, &fd);
-                       purg_lnk(arcn);
-                       break;
-               }
-
-               if ((res > 0) || (docrc && (set_crc(arcn, fd) < 0))) {
+               if (docrc && (set_crc(arcn, fd) < 0)) {
                        /*
                         * unable to obtain the crc we need, close the file,
                         * purge link table entry