experimental/shadow

For /etc/skel/* files put file contents into user directories rather than
"symlinks". This way users can edit their .bashrc files.

This small patch works fine with the multi-shell-support topic branch found on
my github page which rewrites .bashrc and similar files to source /etc/ files.
Thus users can opt-out or set options - still following system updates.

Signed-off-by: Marc Weber <marco-oweber@gmx.de>

pkgs/os-specific/linux/shadow/default.nix

@@ -24,7 +24,19 @@ stdenv.mkDerivation rec {
 
   buildInputs = stdenv.lib.optional (pam != null && stdenv.isLinux) pam;
 
-  patches = [ ./keep-path.patch dots_in_usernames ];
+  patches = [ ./keep-path.patch dots_in_usernames 
+    /* nixos managed /etc[/skel] files are symlinks pointing to /etc/static[/skel]
+    * thus useradd will create symlinks ~/.bashrc. This patch fixes it: If a file
+    * should be copied to user's home directory and it points to /etc/static
+    * the target of the symbolic link is copied instead.
+    * This is only one way to fix it. The alternative would be making nixos
+    * create files in /etc/skel and keep some state around so that it knows
+    * which files it put there so that it can remove them itself. This more
+    * complicated approach would pay off if multiple apps woulb be using
+    * /etc/skel
+    */
+    ./etc-copy-etc-satic-target.patch
+    ];
 
   # Assume System V `setpgrp (void)', which is the default on GNU variants
   # (`AC_FUNC_SETPGRP' is not cross-compilation capable.)

pkgs/os-specific/linux/shadow/etc-copy-etc-satic-target.patch

@@ -0,0 +1,32 @@
+diff --git a/libmisc/copydir.c b/libmisc/copydir.c
+index fac585c..ddf3788 100644
+--- a/libmisc/copydir.c
++++ b/libmisc/copydir.c
+@@ -490,6 +490,27 @@ static int copy_symlink (const char *src, const char *dst,
+ 	if (NULL == oldlink) {
+ 		return -1;
+ 	}
++      
++        /* NixOS hack: if the link points to a file in /etc/static/ this
++         * means the file is managed by nix and probably its meant to be a
++         * file. So derefence once more until the original store path (real file)
++         * is found*/
++
++
++	if (strncmp (oldlink, "/etc/static/", strlen ("/etc/static/")) == 0) {
++          char *target = readlink_malloc (oldlink);
++          free (oldlink);
++          int r = copy_entry(target, dst, reset_selinux, old_uid, new_uid, old_gid, new_gid);
++
++          /* make writeable by user */
++          struct stat s;
++          stat(dst, &s);
++          s.st_mode |= S_IWUSR; // u+w
++          chmod(dst, s.st_mode); // not minding higher bits because chmod (coreutils) doesn't either
++
++          free (target);
++          return r;
++        }
+ 
+ 	/* If src was a link to an entry of the src_orig directory itself,
+ 	 * create a link to the corresponding entry in the dst_orig