GNU sed version 4.1, bug report

[Terry Chan]

sed-4.1 does NOT correctly perform chmod/chown when
using the "sed -i" (edit in-place) feature.

sed-4.0.9 does work.

Simple test case:

1. touch this_is_an_empty_testfile
2. chmod 755 this_is_an_empty_testfile
3. chown 1000:1000 this_is_an_empty_testfile
4. sed -i "s/XX/x/" this_is_an_empty_testfile
5. ls -al this_is_an_empty_testfile

And this will now show uid:gid of 0:0 and permissions of 600 for
this_is_an_empty_testfile

The problem is located in execute.c and the rewrite/changes in
4.1 vs 4.0.9.

Specifically 4.1 execute.c line 675 still uses:
  fchmod (output_fd, st.st_mode);

which is how sed-4.0.9 invokes the chmod as well.  The problem is
sed-4.1 does NOT use output_fd and now uses output_file.fp !!!!
Similarly fchown usage is incorrect too as it still uses output_fd,
but should be using output_file.fp.

This bug in sed-4.1 clearly breaks the chmod and chown functionality that
was working in sed-4.0.9.

Terry Chan
Lunar Linux Developer