Re: [Qemu-devel] [PATCH v2] linux-user: ioctl() command type is int

[Riku Voipio <riku.voipio@linaro.org>]

On 16 June 2015 at 01:35, Laurent Vivier <laurent@vivier.eu> wrote:
> When executing a 64bit target chroot on 64bit host,
> the ioctl() command can mismatch.
>
> It seems the previous commit doesn't solve the problem in
> my case:
>
>         9c6bf9c7 linux-user: Fix ioctl cmd type mismatch on 64-bit targets
>
> For example, a ppc64 chroot on an x86_64 host:
>
> bash-4.3# ls
> Unsupported ioctl: cmd=0x80087467
> Unsupported ioctl: cmd=0x802c7415
>
> The origin of the problem is in syscall.c:do_ioctl().
>
>         static abi_long do_ioctl(int fd, abi_long cmd, abi_long arg)
>
> In this case (ppc64) abi_long is long (on the x86_64), and
>
>     cmd = 0x0000000080087467
>
> then
>         if (ie->target_cmd == cmd)
>
> target_cmd is int, so target_cmd = 0x80087467
> and to compare an int with a long, the sign is extended to 64bit,
> so the comparison is:
>
>         if (0xffffffff80087467 == 0x0000000080087467)
>
> which doesn't match whereas it should.
>
> This patch uses int in the case of the target command type
> instead of abi_long.
>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
> v2: Don't modify IOCTLEntry type (useless and introduce clang errors)

Thanks, tested to build with clang, will refresh pull request in a moment.

>  linux-user/syscall.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index b98b7e7..5a280c3 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -3645,7 +3645,7 @@ enum {
>  typedef struct IOCTLEntry IOCTLEntry;
>
>  typedef abi_long do_ioctl_fn(const IOCTLEntry *ie, uint8_t *buf_temp,
> -                             int fd, abi_long cmd, abi_long arg);
> +                             int fd, int cmd, abi_long arg);
>
>  struct IOCTLEntry {
>      int target_cmd;
> @@ -3671,7 +3671,7 @@ struct IOCTLEntry {
>                              / sizeof(struct fiemap_extent))
>
>  static abi_long do_ioctl_fs_ioc_fiemap(const IOCTLEntry *ie, uint8_t *buf_temp,
> -                                       int fd, abi_long cmd, abi_long arg)
> +                                       int fd, int cmd, abi_long arg)
>  {
>      /* The parameter for this ioctl is a struct fiemap followed
>       * by an array of struct fiemap_extent whose size is set
> @@ -3752,7 +3752,7 @@ static abi_long do_ioctl_fs_ioc_fiemap(const IOCTLEntry *ie, uint8_t *buf_temp,
>  #endif
>
>  static abi_long do_ioctl_ifconf(const IOCTLEntry *ie, uint8_t *buf_temp,
> -                                int fd, abi_long cmd, abi_long arg)
> +                                int fd, int cmd, abi_long arg)
>  {
>      const argtype *arg_type = ie->arg_type;
>      int target_size;
> @@ -3846,7 +3846,7 @@ static abi_long do_ioctl_ifconf(const IOCTLEntry *ie, uint8_t *buf_temp,
>  }
>
>  static abi_long do_ioctl_dm(const IOCTLEntry *ie, uint8_t *buf_temp, int fd,
> -                            abi_long cmd, abi_long arg)
> +                            int cmd, abi_long arg)
>  {
>      void *argptr;
>      struct dm_ioctl *host_dm;
> @@ -4071,7 +4071,7 @@ out:
>  }
>
>  static abi_long do_ioctl_blkpg(const IOCTLEntry *ie, uint8_t *buf_temp, int fd,
> -                               abi_long cmd, abi_long arg)
> +                               int cmd, abi_long arg)
>  {
>      void *argptr;
>      int target_size;
> @@ -4124,7 +4124,7 @@ out:
>  }
>
>  static abi_long do_ioctl_rt(const IOCTLEntry *ie, uint8_t *buf_temp,
> -                                int fd, abi_long cmd, abi_long arg)
> +                                int fd, int cmd, abi_long arg)
>  {
>      const argtype *arg_type = ie->arg_type;
>      const StructEntry *se;
> @@ -4187,7 +4187,7 @@ static abi_long do_ioctl_rt(const IOCTLEntry *ie, uint8_t *buf_temp,
>  }
>
>  static abi_long do_ioctl_kdsigaccept(const IOCTLEntry *ie, uint8_t *buf_temp,
> -                                     int fd, abi_long cmd, abi_long arg)
> +                                     int fd, int cmd, abi_long arg)
>  {
>      int sig = target_to_host_signal(arg);
>      return get_errno(ioctl(fd, ie->host_cmd, sig));
> @@ -4204,7 +4204,7 @@ static IOCTLEntry ioctl_entries[] = {
>
>  /* ??? Implement proper locking for ioctls.  */
>  /* do_ioctl() Must return target values and target errnos. */
> -static abi_long do_ioctl(int fd, abi_long cmd, abi_long arg)
> +static abi_long do_ioctl(int fd, int cmd, abi_long arg)
>  {
>      const IOCTLEntry *ie;
>      const argtype *arg_type;
> --
> 2.4.3
>