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authorGiuseppe Musacchio <thatlemon@gmail.com>2019-05-03 14:20:07 +0200
committerLaurent Vivier <laurent@vivier.eu>2019-05-10 12:44:22 +0200
commitd87146bce08d3d2ea6c00025d7ee0bfa77991692 (patch)
tree3a7f137303b017ec581ca54e0ccaeca636614d8f /linux-user
parent43330b7169ae76222472a4b20c7f4db9d8880527 (diff)
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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: 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>
Diffstat (limited to 'linux-user')
-rw-r--r--linux-user/elfload.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index d08fe23..ef42e02 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -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;