Re: [RFC PATCH glibc 1/12] hurd: Refactor readlinkat()

[Samuel Thibault]

Applied, thanks!

Sergey Bugaev via Libc-alpha, le dim. 12 févr. 2023 14:10:32 +0300, a ecrit:
> Make the code flow more linear using early returns where possible. This
> makes it so much easier to reason about what runs on error / successful
> code paths.
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  sysdeps/mach/hurd/readlinkat.c | 55 ++++++++++++++++++++--------------
>  1 file changed, 32 insertions(+), 23 deletions(-)
> 
> diff --git a/sysdeps/mach/hurd/readlinkat.c b/sysdeps/mach/hurd/readlinkat.c
> index 1efb09ca..dabdbb37 100644
> --- a/sysdeps/mach/hurd/readlinkat.c
> +++ b/sysdeps/mach/hurd/readlinkat.c
> @@ -31,38 +31,47 @@ __readlinkat (int fd, const char *file_name, char *buf, 
> size_t len)
>    error_t err;
>    file_t file_stat;
>    struct stat64 st;
> +  enum retry_type doretry;
> +  char retryname[1024];
> +  file_t file;
> +  char *rbuf = buf;
>  
>    file_stat = __file_name_lookup_at (fd, 0, file_name, O_NOLINK, 0);
>    if (file_stat == MACH_PORT_NULL)
>      return -1;
>  
>    err = __io_stat (file_stat, &st);
> -  if (! err)
> -    if (S_ISLNK (st.st_mode))
> -      {
> -     enum retry_type doretry;
> -     char retryname[1024];
> -     file_t file;
> -     char *rbuf = buf;
> +  if (err)
> +    goto out;
> +  if (!S_ISLNK (st.st_mode))
> +    {
> +      err = EINVAL;
> +      goto out;
> +    }
>  
> -     err = __dir_lookup (file_stat, "", O_READ | O_NOLINK, 0, &doretry, 
> retryname, &file);
> -     if (! err && (doretry != FS_RETRY_NORMAL || retryname[0] != '\0'))
> -       err = EGRATUITOUS;
> -     if (! err)
> -       {
> -         err = __io_read (file, &rbuf, &len, 0, len);
> -         if (!err && rbuf != buf)
> -           {
> -             memcpy (buf, rbuf, len);
> -             __vm_deallocate (__mach_task_self (), (vm_address_t)rbuf, len);
> -           }
> +  err = __dir_lookup (file_stat, "", O_READ | O_NOLINK,
> +                      0, &doretry, retryname, &file);
> +  if (err)
> +    goto out;
> +  if (doretry != FS_RETRY_NORMAL || retryname[0] != '\0')
> +    {
> +      err = EGRATUITOUS;
> +      goto out;
> +    }
> +
> +  err = __io_read (file, &rbuf, &len, 0, len);
> +  __mach_port_deallocate (__mach_task_self (), file);
> +  if (err)
> +    goto out;
> +
> +  if (rbuf != buf)
> +    {
> +      memcpy (buf, rbuf, len);
> +      __vm_deallocate (__mach_task_self (), (vm_address_t) rbuf, len);
> +    }
>  
> -         __mach_port_deallocate (__mach_task_self (), file);
> -       }
> -      }
> -    else
> -      err = EINVAL;
>  
> + out:
>    __mach_port_deallocate (__mach_task_self (), file_stat);
>  
>    return err ? __hurd_fail (err) : len;
> -- 
> 2.39.1
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.