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: Giuseppe Musacchio <thatlemon@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20190503122007.lkjsvztgt4ycovac@debian>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Giuseppe Musacchio 2019-05-03 14:20:07 +02:00 committed by Laurent Vivier
parent 43330b7169
commit d87146bce0

View File

@ -2366,11 +2366,19 @@ 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,
image_fd, eppnt->p_offset - vaddr_po);
if (error == -1) {
goto exit_perror;
/*
* 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;