Re: [PATCH 03/35] rt: Replace generic stub of shm_open with the posix version

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 03/06/2021 20:15, Florian Weimer via Libc-alpha wrote:
> Result of: git mv -f sysdeps/posix/shm_open.c rt
> and manual removal of the _POSIX_MAPPED_FILES preprocessor condition.

LGTM, thanks.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> ---
>  rt/shm_open.c            | 34 ++++++++++++++++++----
>  sysdeps/posix/shm_open.c | 62 ----------------------------------------
>  2 files changed, 29 insertions(+), 67 deletions(-)
>  delete mode 100644 sysdeps/posix/shm_open.c
> 
> diff --git a/rt/shm_open.c b/rt/shm_open.c
> index e2bd25978a..a89aac4102 100644
> --- a/rt/shm_open.c
> +++ b/rt/shm_open.c
> @@ -1,4 +1,5 @@
> -/* Copyright (C) 2000-2021 Free Software Foundation, Inc.
> +/* shm_open -- open a POSIX shared memory object.  Generic POSIX file version.
> +   Copyright (C) 2001-2021 Free Software Foundation, Inc.
>     This file is part of the GNU C Library.
>  
>     The GNU C Library is free software; you can redistribute it and/or
> @@ -16,13 +17,36 @@
>     <https://www.gnu.org/licenses/>.  */
>  
>  #include <errno.h>
> -#include <sys/mman.h>
> +#include <fcntl.h>
> +#include <pthread.h>
> +#include <shm-directory.h>
> +#include <unistd.h>
>  
>  /* Open shared memory object.  */
>  int
>  shm_open (const char *name, int oflag, mode_t mode)
>  {
> -  __set_errno (ENOSYS);
> -  return -1;
> +  struct shmdir_name dirname;
> +  if (__shm_get_name (&dirname, name, false) != 0)
> +    {
> +      __set_errno (EINVAL);
> +      return -1;
> +    }
> +
> +  oflag |= O_NOFOLLOW | O_CLOEXEC;
> +
> +  /* Disable asynchronous cancellation.  */
> +  int state;
> +  pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
> +
> +  int fd = open (dirname.name, oflag, mode);
> +  if (fd == -1 && __glibc_unlikely (errno == EISDIR))
> +    /* It might be better to fold this error with EINVAL since
> +       directory names are just another example for unsuitable shared
> +       object names and the standard does not mention EISDIR.  */
> +    __set_errno (EINVAL);
> +
> +  pthread_setcancelstate (state, NULL);
> +
> +  return fd;
>  }
> -stub_warning (shm_open)
> diff --git a/sysdeps/posix/shm_open.c b/sysdeps/posix/shm_open.c
> deleted file mode 100644
> index 1817c52f7f..0000000000
> --- a/sysdeps/posix/shm_open.c
> +++ /dev/null
> @@ -1,62 +0,0 @@
> -/* shm_open -- open a POSIX shared memory object.  Generic POSIX file version.
> -   Copyright (C) 2001-2021 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   The GNU C Library is free software; you can redistribute it and/or
> -   modify it under the terms of the GNU Lesser General Public
> -   License as published by the Free Software Foundation; either
> -   version 2.1 of the License, or (at your option) any later version.
> -
> -   The GNU C Library is distributed in the hope that it will be useful,
> -   but WITHOUT ANY WARRANTY; without even the implied warranty of
> -   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> -   Lesser General Public License for more details.
> -
> -   You should have received a copy of the GNU Lesser General Public
> -   License along with the GNU C Library; if not, see
> -   <https://www.gnu.org/licenses/>.  */
> -
> -#include <unistd.h>
> -
> -#if ! _POSIX_MAPPED_FILES
> -
> -# include <rt/shm_open.c>
> -
> -#else
> -
> -# include <errno.h>
> -# include <fcntl.h>
> -# include <pthread.h>
> -# include <shm-directory.h>
> -
> -
> -/* Open shared memory object.  */
> -int
> -shm_open (const char *name, int oflag, mode_t mode)
> -{
> -  struct shmdir_name dirname;
> -  if (__shm_get_name (&dirname, name, false) != 0)
> -    {
> -      __set_errno (EINVAL);
> -      return -1;
> -    }
> -
> -  oflag |= O_NOFOLLOW | O_CLOEXEC;
> -
> -  /* Disable asynchronous cancellation.  */
> -  int state;
> -  pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
> -
> -  int fd = open (dirname.name, oflag, mode);
> -  if (fd == -1 && __glibc_unlikely (errno == EISDIR))
> -    /* It might be better to fold this error with EINVAL since
> -       directory names are just another example for unsuitable shared
> -       object names and the standard does not mention EISDIR.  */
> -    __set_errno (EINVAL);
> -
> -  pthread_setcancelstate (state, NULL);
> -
> -  return fd;
> -}
> -
> -#endif  /* _POSIX_MAPPED_FILES */
>