[PATCH] Cygwin: fix return value of symlink_info::check
Tue Aug 9 20:52:58 GMT 2022
v2 attached with a more accurate commit message.
On 8/9/2022 3:52 PM, Ken Brown wrote:
> Patch attached. Please check my changes to the commentary preceding
> symlink_info::check to make sure I got it right.
> I've written the patch against the master branch, but I think it should be
> applied to cygwin-3_3-branch also.
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From d1aee2f7e022497d57d55ffcd69ddaa7d7b123b2 Mon Sep 17 00:00:00 2001
From: Ken Brown <email@example.com>
Date: Tue, 9 Aug 2022 15:14:07 -0400
Subject: [PATCH v2] Cygwin: fix return value of symlink_info::check
Currently it is possible for symlink_info::check to return -1 in case
we're searching for foo and find foo.lnk that is not a Cygwin symlink.
This contradicts the new meaning attached to a negative return value
in commit 19d59ce75d. Fix this by setting "res" to 0 at the beginning
of the main loop and not seting it to -1 later.
Also fix the commentary preceding the function definition to reflect
the current behavior.
winsup/cygwin/path.cc | 22 +++++++++-------------
winsup/cygwin/release/3.3.6 | 4 ++++
2 files changed, 13 insertions(+), 13 deletions(-)
diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc
index 3e436dc65..227b99d0f 100644
@@ -3027,19 +3027,16 @@ symlink_info::parse_device (const char *contents)
/* Check if PATH is a symlink. PATH must be a valid Win32 path name.
If PATH is a symlink, put the value of the symlink--the file to
- which it points--into BUF. The value stored in BUF is not
- necessarily null terminated. BUFLEN is the length of BUF; only up
- to BUFLEN characters will be stored in BUF. BUF may be NULL, in
- which case nothing will be stored.
+ which it points--into CONTENTS.
- Set *SYML if PATH is a symlink.
+ Set PATH_SYMLINK if PATH is a symlink.
- Set *EXEC if PATH appears to be executable. This is an efficiency
- hack because we sometimes have to open the file anyhow. *EXEC will
- not be set for every executable file.
- Return -1 on error, 0 if PATH is not a symlink, or the length
- stored into BUF if PATH is a symlink. */
+ If PATH is a symlink, return the length stored into CONTENTS. If
+ the inner components of PATH contain native symlinks or junctions,
+ or if the drive is a virtual drive, compare PATH with the result
+ returned by GetFinalPathNameByHandleA. If they differ, store the
+ final path in CONTENTS and return the negative of its length. In
+ all other cases, return 0. */
symlink_info::check (char *path, const suffix_info *suffixes, fs_info &fs,
@@ -3094,6 +3091,7 @@ restart:
while (suffix.next ())
+ res = 0;
error = 0;
get_nt_native_path (suffix.path, upath, mount_flags & MOUNT_DOS);
@@ -3345,8 +3343,6 @@ restart:
- res = -1;
/* Reparse points are potentially symlinks. This check must be
performed before checking the SYSTEM attribute for sysfile
symlinks, since reparse points can have this flag set, too. */
diff --git a/winsup/cygwin/release/3.3.6 b/winsup/cygwin/release/3.3.6
index 078e6e520..364e0cb0d 100644
@@ -35,3 +35,7 @@ Bug Fixes
- Fix a problem that prevented some symbolic links to /cygdrive/C,
/cygdrive/./c, /cygdrive//c, etc. from working.
+- Fix a path handling bug that could cause a non-existing file to be
+ treated as the current directory.
+ Addresses: https://cygwin.com/pipermail/cygwin/2022-August/252030.html
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