Re: [Qemu-devel] [PATCH] linux-user: fix emulation of getdents

[Wei-Ren Chen]

  CC'ed to linux-user maintainer, Riku.

On Fri, Aug 17, 2012 at 01:20:19AM +0400, Dmitry V. Levin wrote:
> In case when TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64, the last
> byte of the target dirent structure (aka d_type byte) was never copied
> from the native dirent structure, thus breaking everything that relies
> on valid d_type value, e.g. glob(3).
> 
> Signed-off-by: Dmitry V. Levin <address@hidden>
> ---
>  linux-user/syscall.c      | 7 +++----
>  linux-user/syscall_defs.h | 3 ++-
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 41c869b..2b6025b 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -7030,10 +7030,9 @@ abi_long do_syscall(void *cpu_env, int num, abi_long 
> arg1,
>                      tde->d_ino = tswapal(de->d_ino);
>                      tde->d_off = tswapal(de->d_off);
>                   tnamelen = treclen - (2 * sizeof(abi_long) + 2);
> -                 if (tnamelen > 256)
> -                        tnamelen = 256;
> -                    /* XXX: may not be correct */
> -                    pstrcpy(tde->d_name, tnamelen, de->d_name);
> +                 if (tnamelen > sizeof(tde->d_name))
> +                        tnamelen = sizeof(tde->d_name);
> +                    memcpy(tde->d_name, de->d_name, tnamelen);
>                      de = (struct linux_dirent *)((char *)de + reclen);
>                      len -= reclen;
>                      tde = (struct target_dirent *)((char *)tde + treclen);
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 2cfda5a..f27a8d4 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -258,7 +258,8 @@ struct target_dirent {
>       abi_long        d_ino;
>       abi_long        d_off;
>       unsigned short  d_reclen;
> -     char            d_name[256]; /* We must not include limits.h! */
> +     char            d_name[257];    /* We must not include limits.h! */
> +                                     /* 257 = NAME_MAX + '\0' + d_type */
>  };
>  
>  struct target_dirent64 {
> 
> -- 
> ldv

-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj