From: Pádraig Brady <P@draigBrady.com>
Date: Mon, 19 Aug 2024 11:43:09 +0000 (+0100)
Subject: install: dereference source symlinks when comparing
X-Git-Tag: v9.6~176
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=403cb48413519396b7df0943cb5fbab5b3d5b3e2;p=thirdparty%2Fcoreutils.git

install: dereference source symlinks when comparing

* NEWS: Mention the change in behavior.
* src/install.c (need_copy): s/lstat/stat/ for the source.
* tests/install/install-C.sh: Add test cases
(and improve existing test case which wan't valid
due to the existing non standard modes on test files).
Addresses https://bugs.gnu.org/72707
---

diff --git a/NEWS b/NEWS
index 65cc3fde00..e1d3f82d17 100644
--- a/NEWS
+++ b/NEWS
@@ -24,6 +24,9 @@ GNU coreutils NEWS                                    -*- outline -*-
 
 ** Changes in behavior
 
+  install -C now dereferences symlink sources when comparing,
+  rather than always treating as different and performing the copy.
+
   ls's -f option now simply acts like -aU, instead of also ignoring
   some earlier options.  For example 'ls -fl' and 'ls -lf' are now
   equivalent because -f no longer ignores an earlier -l.  The new
diff --git a/src/install.c b/src/install.c
index 939db9cd41..85f2d9e110 100644
--- a/src/install.c
+++ b/src/install.c
@@ -177,7 +177,7 @@ need_copy (char const *src_name, char const *dest_name,
     return true;
 
   /* compare files using stat */
-  if (lstat (src_name, &src_sb) != 0)
+  if (stat (src_name, &src_sb) != 0)
     return true;
 
   if (fstatat (dest_dirfd, dest_relname, &dest_sb, AT_SYMLINK_NOFOLLOW) != 0)
diff --git a/tests/install/install-C.sh b/tests/install/install-C.sh
index a6b332e14c..2751fb0b6c 100755
--- a/tests/install/install-C.sh
+++ b/tests/install/install-C.sh
@@ -78,9 +78,18 @@ compare out out_installed_second || fail=1
 ginstall -Cv -m$mode3 a b > out || fail=1
 compare out out_installed_second || fail=1
 
-# files are not regular files
+# non regular files
+ginstall -v -m$mode1 a b > out || fail=1  # reset to regular mode
+compare out out_installed_second || fail=1
+# symlink source is always dereferenced (and so regular here)
+ginstall -v -m$mode1 a d > out || fail=1  # create regular dest
+echo "'a' -> 'd'" > out_installed_first_ad || framework_failure_
+compare out out_installed_first_ad || fail=1
 ln -s a c || framework_failure_
-ln -s b d || framework_failure_
+ginstall -Cv -m$mode1 c d > out || fail=1
+compare out out_empty || fail=1
+# symlink dest never created by install so deemed non regular
+ln -nsf b d || framework_failure_
 ginstall -Cv -m$mode1 c d > out || fail=1
 echo "removed 'd'
 'c' -> 'd'" > out_installed_second_cd