Commit d87146bc authored by Giuseppe Musacchio's avatar Giuseppe Musacchio Committed by Laurent Vivier
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linux-user: elf: Map empty PT_LOAD segments 



Some PT_LOAD segments may be completely zeroed out and their p_filesize
is zero, in that case the loader should just allocate a page that's at
least p_memsz bytes large (plus eventual alignment padding).

Calling zero_bss does this job for us, all we have to do is make sure we
don't try to mmap a zero-length page.

Signed-off-by: default avatarGiuseppe Musacchio <thatlemon@gmail.com>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Message-Id: <20190503122007.lkjsvztgt4ycovac@debian>
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
parent 43330b71

linux-user/elfload.c

+13 −5
Original line number Diff line number Diff line
@@ -2366,12 +2366,20 @@ static void load_elf_image(const char *image_name, int image_fd, 
            vaddr_ps = TARGET_ELF_PAGESTART(vaddr);

            vaddr_len = TARGET_ELF_PAGELENGTH(eppnt->p_filesz + vaddr_po);



            error = target_mmap(vaddr_ps, vaddr_len,

                                elf_prot, MAP_PRIVATE | MAP_FIXED,

            /*

             * Some segments may be completely empty without any backing file

             * segment, in that case just let zero_bss allocate an empty buffer

             * for it.

             */

            if (eppnt->p_filesz != 0) {

                error = target_mmap(vaddr_ps, vaddr_len, elf_prot,

                                    MAP_PRIVATE | MAP_FIXED,

                                    image_fd, eppnt->p_offset - vaddr_po);



                if (error == -1) {

                    goto exit_perror;

                }

            }



            vaddr_ef = vaddr + eppnt->p_filesz;

            vaddr_em = vaddr + eppnt->p_memsz;