xz: Make --keep accept symlinks, hardlinks, and setuid/setgid/sticky.

Previously this required using --force but that has other
effects too which might be undesirable. Changing the behavior
of --keep has a small risk of breaking existing scripts but
since this is a fairly special corner case I expect the
likehood of breakage to be low enough.

I think the new behavior is more logical. The only reason for
the old behavior was to be consistent with gzip and bzip2.

Thanks to Vincent Lefevre and Sebastian Andrzej Siewior.

diff --git a/src/xz/file_io.c b/src/xz/file_io.c
index e1a37d5f930fa8ddde842470ec7bd33438dbd729..80b56d38c0370b31032b3a2331df64f840eedd25 100644 (file)
--- a/src/xz/file_io.c
+++ b/src/xz/file_io.c
@@ -536,8 +536,9 @@ io_open_src_real(file_pair *pair)
        }
 
        // Symlinks are not followed unless writing to stdout or --force
-       // was used.
-       const bool follow_symlinks = opt_stdout || opt_force;
+       // or --keep was used.
+       const bool follow_symlinks
+                       = opt_stdout || opt_force || opt_keep_original;
 
        // We accept only regular files if we are writing the output
        // to disk too. bzip2 allows overriding this with --force but
@@ -674,7 +675,7 @@ io_open_src_real(file_pair *pair)
        }
 
 #ifndef TUKLIB_DOSLIKE
-       if (reg_files_only && !opt_force) {
+       if (reg_files_only && !opt_force && !opt_keep_original) {
                if (pair->src_st.st_mode & (S_ISUID | S_ISGID)) {
                        // gzip rejects setuid and setgid files even
                        // when --force was used. bzip2 doesn't check
@@ -683,7 +684,7 @@ io_open_src_real(file_pair *pair)
                        // and setgid bits there.
                        //
                        // We accept setuid and setgid files if
-                       // --force was used. We drop these bits
+                       // --force or --keep was used. We drop these bits
                        // explicitly in io_copy_attr().
                        message_warning(_("%s: File has setuid or "
                                        "setgid bit set, skipping"),

diff --git a/src/xz/xz.1 b/src/xz/xz.1
index db9de4ffe34c787e2de9193cae7588ee596695b3..9721ed394583911edad2a432c97f83ea4114cd54 100644 (file)
--- a/src/xz/xz.1
+++ b/src/xz/xz.1
@@ -5,7 +5,7 @@
 .\" This file has been put into the public domain.
 .\" You can do whatever you want with this file.
 .\"
-.TH XZ 1 "2020-11-01" "Tukaani" "XZ Utils"
+.TH XZ 1 "2021-01-11" "Tukaani" "XZ Utils"
 .
 .SH NAME
 xz, unxz, xzcat, lzma, unlzma, lzcat \- Compress or decompress .xz and .lzma files
@@ -392,6 +392,20 @@ should be used.
 .TP
 .BR \-k ", " \-\-keep
 Don't delete the input files.
+.IP ""
+Since
+.B xz
+5.4.0,
+this option also makes
+.B xz
+compress or decompress even if the input is
+a symbolic link to a regular file,
+has more than one hard link,
+or has the setuid, setgid, or sticky bit set.
+The setuid, setgid, and sticky bits are not copied
+to the target file.
+In earlier versions this was only done with
+.BR \-\-force .
 .TP
 .BR \-f ", " \-\-force
 This option has several effects: