Re: [Qemu-devel] Patch to fix mapping of elf pheaders specifying both .data and .bss segments

[Riku Voipio <riku.voipio@iki.fi>]

On Thu, Aug 06, 2009 at 03:41:02PM -0700, Kai Backman wrote:
> On Thu, Jun 18, 2009 at 11:57 AM, Riku Voipio<riku.voipio@iki.fi> wrote:
> > The patch attached is totally messed up thou.
> 
> Sorry for the delay. I was vacationing in Finland (incidentally)..
> 
> To restart the thread, I've re-attached the patch.

I see Max Filippov has touched the same function for possibly the same
issue?

http://lists.gnu.org/archive/html/qemu-devel/2009-07/msg00902.html

> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index 190ad14..e4e75d5 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -1211,7 +1211,7 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
>      abi_ulong mapped_addr;
>      struct elf_phdr * elf_ppnt;
>      struct elf_phdr *elf_phdata;
> -    abi_ulong elf_bss, k, elf_brk;
> +    abi_ulong elf_bss, last_bss, mapped_bss, k, elf_brk;
>      int retval;
>      char * elf_interpreter;
>      abi_ulong elf_entry, interp_load_addr = 0;
> @@ -1271,6 +1271,7 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
>      elf_ppnt = elf_phdata;
>  
>      elf_bss = 0;
> +    last_bss = 0;
>      elf_brk = 0;
>  
>  
> @@ -1495,12 +1496,24 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
>          k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
>          if (k > elf_bss)
>              elf_bss = k;
> +        k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
> +        if (k > last_bss)
> +            last_bss = k;
>          if ((elf_ppnt->p_flags & PF_X) && end_code <  k)
>              end_code = k;
>          if (end_data < k)
>              end_data = k;
>          k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
>          if (k > elf_brk) elf_brk = k;
> +        if (!elf_interpreter && last_bss > elf_bss) {
> +      	    padzero(elf_bss, last_bss);
> +	    mapped_bss = TARGET_ELF_PAGESTART(elf_bss + qemu_host_page_size - 1);
> +
> +	    /* Map the last of the bss segment */
> +            target_mmap(load_bias + mapped_bss, last_bss-mapped_bss,
> +                        PROT_READ|PROT_WRITE|PROT_EXEC,
> +                        MAP_FIXED|MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
> +        }
>      }
>  
>      elf_entry += load_bias;