brp-mangle-shebangs: fix unsafe/incorrect command expansion

trim() {
  printf '%s' "$*"
}
...
  read shebang_line < "$f" || :
  orig_shebang=$(trim $(echo "$shebang_line" | grep -Po "#!\K.*" || echo))

The "trimming", i.e. replacement of multiple spaces and removal of leading
and trailing spaces, is achieved because "trim $(cmd)" construct has an
unquoted $(), which is subject to word splitting.

This works, yes. BUT.

It is also subject to glob expansion - any ?s and *s will be attempted
to be expanded as well - definitely NOT what we want!

This change replaces this trick with code which avoids the expansion issue,
and which does not spawn any subprocesses for string manipulations -
this is ~3 times faster (fork+execs are expensive).

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

0 files changed, 0 insertions, 0 deletions