From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.bugs Subject: bug#28156: Emacs quietly munges symlink contents Date: Sun, 20 Aug 2017 10:54:45 -0700 Organization: UCLA Computer Science Department Message-ID: References: <68b2e6ef-bf0b-ebcf-c577-d296952d593f@cs.ucla.edu> <83pobqcnlf.fsf@gnu.org> <83h8x2ckqn.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------5539653B2399E54E7B1DA5D5" X-Trace: blaine.gmane.org 1503252143 27145 195.159.176.226 (20 Aug 2017 18:02:23 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 20 Aug 2017 18:02:23 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 Cc: michael.albinus@gmx.de, 28156@debbugs.gnu.org To: Eli Zaretskii , Philipp Stephani Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sun Aug 20 20:02:19 2017 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1djUYC-0006gN-5I for geb-bug-gnu-emacs@m.gmane.org; Sun, 20 Aug 2017 20:02:16 +0200 Original-Received: from localhost ([::1]:43369 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1djUYI-0007aq-M0 for geb-bug-gnu-emacs@m.gmane.org; Sun, 20 Aug 2017 14:02:22 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:41242) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1djURF-0001Kq-B2 for bug-gnu-emacs@gnu.org; Sun, 20 Aug 2017 13:55:06 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1djURC-0000rX-6n for bug-gnu-emacs@gnu.org; Sun, 20 Aug 2017 13:55:05 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:38168) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1djURC-0000rT-3X for bug-gnu-emacs@gnu.org; Sun, 20 Aug 2017 13:55:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1djURB-0002ca-PX for bug-gnu-emacs@gnu.org; Sun, 20 Aug 2017 13:55:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Paul Eggert Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 20 Aug 2017 17:55:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 28156 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: patch Original-Received: via spool by 28156-submit@debbugs.gnu.org id=B28156.150325169910063 (code B ref 28156); Sun, 20 Aug 2017 17:55:01 +0000 Original-Received: (at 28156) by debbugs.gnu.org; 20 Aug 2017 17:54:59 +0000 Original-Received: from localhost ([127.0.0.1]:46849 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1djUR8-0002cF-LU for submit@debbugs.gnu.org; Sun, 20 Aug 2017 13:54:59 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:43468) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1djUR6-0002c2-Hc for 28156@debbugs.gnu.org; Sun, 20 Aug 2017 13:54:57 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 745B41608B2; Sun, 20 Aug 2017 10:54:50 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id 05LGzG7O2ETp; Sun, 20 Aug 2017 10:54:49 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 41AC7160888; Sun, 20 Aug 2017 10:54:49 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id BEem7sLyfDO4; Sun, 20 Aug 2017 10:54:49 -0700 (PDT) Original-Received: from [192.168.1.9] (unknown [47.153.184.153]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 1454E160882; Sun, 20 Aug 2017 10:54:49 -0700 (PDT) In-Reply-To: <83h8x2ckqn.fsf@gnu.org> Content-Language: en-US X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:135948 Archived-At: This is a multi-part message in MIME format. --------------5539653B2399E54E7B1DA5D5 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Eli Zaretskii wrote: > We have quoting for these cases. Quoting does not work for these cases. If I try to rename a symlink to th= e=20 literal string '~eggert' on my machine, Emacs will misbehave as described= and=20 there is no way to quote the string naming the symlink to fix this. > doesn't Emacs behave here like Unix shell commands do? They differ in many ways. Two examples. First, the Unix shell command 'ln= -s=20 ~/$$ def' expands both the "~" and the "$$", whereas (make-symbolic-link = "~/$$"=20 "def") expands only the "~". Second, the Unix shell command "ln -s def" c= reates=20 a symlink to itself, whereas (make-symbolic-link "def") is an error. Brie= fly,=20 the Unix shell commands are higher-level than the Emacs primitives. The main points here are (1) Emacs functions should let users create and=20 manipulate whatever symlinks they want to, and (2) the documentation has = long=20 said that symlinks are not expanded. > If make-symbolic-link would create a link like this: >=20 > ttt -> ~/bin/etags >=20 > (which is what your proposed change does, right?), then programs which > follow the link will probably fail Yes, they will fail unless there is a directory named '~'. That is the in= tent.=20 If I want to create a symlink to my home directory, I can use expand-file= -name=20 on the link target, before calling make-symbolic-link. > this text should be clarified. Sure, that's easy. Revised patch attached. --------------5539653B2399E54E7B1DA5D5 Content-Type: text/x-patch; name="0001-Do-not-munge-contents-of-local-symbolic-links.patch" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="0001-Do-not-munge-contents-of-local-symbolic-links.patch" =46rom 6a3f716feac756a6e80ba4c571155377bd1cba28 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sun, 20 Aug 2017 03:13:52 -0700 Subject: [PATCH] Do not munge contents of local symbolic links This lets Emacs deal with arbitrary local symlinks without mishandling their contents. For example, (progn (shell-command "ln -fs '~' 'x'") (rename-file "x" "/tmp/x")) now consistently creates a symbolic link from '/tmp/x' to '~'. Formerly, it did that only if the working directory was on the same filesystem as /tmp; otherwise, it expanded the '~' to the user's home directory. * etc/NEWS: Document the change. * src/fileio.c (Fmake_symbolic_link): Do not expand leading "~" in the target, and look for special constructs only in the new link name, not the target. (emacs_readlinkat): Do not preprend "/:" to the link target if it starts with "/" and contains ":" before NUL. * test/lisp/net/tramp-tests.el (tramp-test21-file-links): Adjust to new behavior. * test/src/fileio-tests.el (try-link): Rename from try-char, and accept a string instead of a char. All uses changed. (fileio-tests--symlink-failure): Also test leading ~, and "/:", to test the new behavior. --- etc/NEWS | 15 +++++++++++++++ src/fileio.c | 18 ------------------ test/lisp/net/tramp-tests.el | 9 ++++++--- test/src/fileio-tests.el | 21 ++++++++++----------- 4 files changed, 31 insertions(+), 32 deletions(-) diff --git a/etc/NEWS b/etc/NEWS index 7774d75..3bafb87 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -1204,6 +1204,21 @@ instead of to utf-8. Before this change, Emacs wo= uld sometimes mishandle file names containing these control characters. =20 +++ +** 'file-attributes', 'file-symlink-p' and 'make-symbolic-link' no +longer quietly mutate the target of a local symbolic link, so that +Emacs can access and copy them reliably regardless of their contents. +Two changes are involved. First, 'file-attributes' and +'file-symlink-p' no longer prepend "/:" to symbolic links whose +targets begin with "/" and contain ":". For example, if a symbolic +link "x" has a target "/y:z", (file-symlink-p "x") now returns "/y:z" +rather than "/:/y:z". Second, 'make-symbolic-link' no longer expands +"~" at the start of a link target before creating the link. For +example, (make-symbolic-link "~y" "x") now creates a symbolic link +with target being the string "~y" and not the home directory of the +user y. To create a symbolic link to y's home directory, use +(make-symbolic-link (expand-file-name "~y") "x"). + ++++ ** Module functions are now implemented slightly differently; in particular, the function 'internal--module-call' has been removed. Code that depends on undocumented internals of the module system might diff --git a/src/fileio.c b/src/fileio.c index f954ac1..ce243c3 100644 --- a/src/fileio.c +++ b/src/fileio.c @@ -2423,21 +2423,8 @@ This happens for interactive use with M-x. */) Lisp_Object encoded_target, encoded_linkname; =20 CHECK_STRING (target); - /* If the link target has a ~, we must expand it to get - a truly valid file name. Otherwise, do not expand; - we want to permit links to relative file names. */ - if (SREF (target, 0) =3D=3D '~') - target =3D Fexpand_file_name (target, Qnil); - linkname =3D expand_cp_target (target, linkname); =20 - /* If the file name has special constructs in it, - call the corresponding file handler. */ - handler =3D Ffind_file_name_handler (target, Qmake_symbolic_link); - if (!NILP (handler)) - return call4 (handler, Qmake_symbolic_link, target, - linkname, ok_if_already_exists); - /* If the new link name has special constructs in it, call the corresponding file handler. */ handler =3D Ffind_file_name_handler (linkname, Qmake_symbolic_link); @@ -2635,11 +2622,6 @@ emacs_readlinkat (int fd, char const *filename) return Qnil; =20 val =3D build_unibyte_string (buf); - if (buf[0] =3D=3D '/' && strchr (buf, ':')) - { - AUTO_STRING (slash_colon, "/:"); - val =3D concat2 (slash_colon, val); - } if (buf !=3D readlink_buf) xfree (buf); val =3D DECODE_FILE (val); diff --git a/test/lisp/net/tramp-tests.el b/test/lisp/net/tramp-tests.el index 9dc276b..0740996 100644 --- a/test/lisp/net/tramp-tests.el +++ b/test/lisp/net/tramp-tests.el @@ -2538,13 +2538,16 @@ tramp--test-backtrace (should-error (make-symbolic-link tmp-name1 tmp-name2)) (make-symbolic-link tmp-name1 tmp-name2 'ok-if-already-exists) (should (file-symlink-p tmp-name2)) - ;; `tmp-name3' is a local file name. - (should-error (make-symbolic-link tmp-name1 tmp-name3))) + ;; `tmp-name3' is a local file name, so its target is not + ;; interpreted. + (make-symbolic-link tmp-name1 tmp-name3) + (should (equal tmp-name1 (file-symlink-p tmp-name3)))) =20 ;; Cleanup. (ignore-errors (delete-file tmp-name1) - (delete-file tmp-name2))) + (delete-file tmp-name2) + (delete-file tmp-name3))) =20 ;; Check `add-name-to-file'. (unwind-protect diff --git a/test/src/fileio-tests.el b/test/src/fileio-tests.el index 2ef1b55..5103d2f 100644 --- a/test/src/fileio-tests.el +++ b/test/src/fileio-tests.el @@ -19,14 +19,13 @@ =20 (require 'ert) =20 -(defun try-char (char link) - (let ((target (string char))) - (make-symbolic-link target link) - (let* ((read-link (file-symlink-p link)) - (failure (unless (string-equal target read-link) - (list 'string-equal target read-link)))) - (delete-file link) - failure))) +(defun try-link (target link) + (make-symbolic-link target link) + (let* ((read-link (file-symlink-p link)) + (failure (unless (string-equal target read-link) + (list 'string-equal target read-link)))) + (delete-file link) + failure)) =20 (defun fileio-tests--symlink-failure () (let* ((dir (make-temp-file "fileio" t)) @@ -36,9 +35,9 @@ fileio-tests--symlink-failure (char 0)) (while (and (not failure) (< char 127)) (setq char (1+ char)) - (unless (=3D char ?~) - (setq failure (try-char char link)))) - failure) + (setq failure (try-link (string char) link))) + (or failure + (try-link "/:" link))) (delete-directory dir t)))) =20 (ert-deftest fileio-tests--odd-symlink-chars () --=20 2.7.4 --------------5539653B2399E54E7B1DA5D5--