Re: [Qemu-devel] [PATCH] linux-user: fix inotify

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

On 03/01/2017 09:54 PM, Laurent Vivier wrote:
> When a fd is opened using inotify_init(), a read provides
> one or more inotify_event structures:
>
>     struct inotify_event {
>         int      wd;
>         uint32_t mask;
>         uint32_t cookie;
>         uint32_t len;
>         char     name[];
>     };
>
> The integer fields must be byte-swapped to the target endianness.
>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> ---
>  linux-user/syscall.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index cec8428..c2c4f3a 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -7671,6 +7671,33 @@ static target_timer_t get_timer_id(abi_long arg)
>      return timerid;
>  }
>
> +#if (defined(TARGET_NR_inotify_init) && defined(__NR_inotify_init)) || \
> +    (defined(CONFIG_INOTIFY1) && defined(TARGET_NR_inotify_init1) && \
> +     defined(__NR_inotify_init1))
> +static abi_long host_to_target_data_inotify(void *buf, size_t len)
> +{
> +    struct inotify_event *ev;
> +    int i;
> +    uint32_t name_len;
> +
> +    for (i = 0; i < len; i += sizeof(struct inotify_event) + name_len) {
> +        ev = (struct inotify_event *)((char *)buf + i);
> +        name_len = ev->len;
> +
> +        ev->wd = tswap32(ev->wd);
> +        ev->mask = tswap32(ev->mask);
> +        ev->cookie = tswap32(ev->cookie);
> +        ev->len = tswap32(name_len);
> +    }
> +
> +    return len;
> +}
> +
> +static TargetFdTrans target_inotify_trans = {
> +    .host_to_target_data = host_to_target_data_inotify,
> +};
> +#endif
> +
>  /* do_syscall() should always have a single exit point at the end so
>     that actions, such as logging of syscall results, can be performed.
>     All errnos that do_syscall() returns must be -TARGET_<errcode>. */
> @@ -11694,6 +11721,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>  #if defined(TARGET_NR_inotify_init) && defined(__NR_inotify_init)
>      case TARGET_NR_inotify_init:
>          ret = get_errno(sys_inotify_init());
> +        fd_trans_register(ret, &target_inotify_trans);
>          break;
>  #endif
>  #ifdef CONFIG_INOTIFY1
> @@ -11701,6 +11729,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>      case TARGET_NR_inotify_init1:
>          ret = get_errno(sys_inotify_init1(target_to_host_bitmask(arg1,
>                                            fcntl_flags_tbl)));
> +        fd_trans_register(ret, &target_inotify_trans);
>          break;
>  #endif
>  #endif
>