[Bug dynamic-link/30452] LD_PREFER_MAP_32BIT_EXEC does not work with 2MiB load segment alignment

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=30452

--- Comment #6 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by H.J. Lu <hjl@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=6259ab39410cdefc80077afea48ca9cb057f6005

commit 6259ab39410cdefc80077afea48ca9cb057f6005
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Jun 22 14:30:31 2023 -0700

    ld.so: Always use MAP_COPY to map the first segment [BZ #30452]

    The first segment in a shared library may be read-only, not executable.
    To support LD_PREFER_MAP_32BIT_EXEC on such shared libraries, we also
    check MAP_DENYWRITE to decide if MAP_32BIT should be passed to mmap.
    Normally the first segment is mapped with MAP_COPY, which is defined
    as (MAP_PRIVATE | MAP_DENYWRITE).  But if the segment alignment is
    greater than the page size, MAP_COPY isn't used to allocate enough
    space to ensure that the segment can be properly aligned.  Map the
    first segment with MAP_COPY in this case to fix BZ #30452.

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