Re: [PATCH 1/4] socket: Add the __sockaddr_un_set function

[Siddhesh Poyarekar <siddhesh@gotplt.org>]

On 14/01/2022 13:53, Florian Weimer via Libc-alpha wrote:
> ---
>   include/sys/un.h             | 12 +++++++
>   socket/Makefile              |  6 +++-
>   socket/sockaddr_un_set.c     | 41 ++++++++++++++++++++++++
>   socket/tst-sockaddr_un_set.c | 62 ++++++++++++++++++++++++++++++++++++
>   4 files changed, 120 insertions(+), 1 deletion(-)
>   create mode 100644 socket/sockaddr_un_set.c
>   create mode 100644 socket/tst-sockaddr_un_set.c

LGTM.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

> 
> diff --git a/include/sys/un.h b/include/sys/un.h
> index bdbee99980..152afd9fc7 100644
> --- a/include/sys/un.h
> +++ b/include/sys/un.h
> @@ -1 +1,13 @@
>   #include <socket/sys/un.h>
> +
> +#ifndef _ISOMAC
> +
> +/* Set ADDR->sun_family to AF_UNIX and ADDR->sun_path to PATHNAME.
> +   Return 0 on success or -1 on failure (due to overlong PATHNAME).
> +   The caller should always use sizeof (struct sockaddr_un) as the
> +   socket address length, disregaring the length of PATHNAME.
> +   Only concrete (non-abstract) pathnames are supported.  */
> +int __sockaddr_un_set (struct sockaddr_un *addr, const char *pathname)
> +  attribute_hidden;
> +
> +#endif /* _ISOMAC */
> diff --git a/socket/Makefile b/socket/Makefile
> index 39333e10ca..156eec6c85 100644
> --- a/socket/Makefile
> +++ b/socket/Makefile
> @@ -29,13 +29,17 @@ headers	:= sys/socket.h sys/un.h bits/sockaddr.h bits/socket.h \
>   routines := accept bind connect getpeername getsockname getsockopt	\
>   	    listen recv recvfrom recvmsg send sendmsg sendto		\
>   	    setsockopt shutdown socket socketpair isfdtype opensock	\
> -	    sockatmark accept4 recvmmsg sendmmsg
> +	    sockatmark accept4 recvmmsg sendmmsg sockaddr_un_set
>   
>   tests := \
>     tst-accept4 \
>     tst-sockopt \
>     # tests
>   
> +tests-internal := \
> +  tst-sockaddr_un_set \
> +  # tests-internal
> +
>   tests-time64 := \
>     tst-sockopt-time64 \
>     # tests
> diff --git a/socket/sockaddr_un_set.c b/socket/sockaddr_un_set.c
> new file mode 100644
> index 0000000000..0bd40dc34e
> --- /dev/null
> +++ b/socket/sockaddr_un_set.c
> @@ -0,0 +1,41 @@
> +/* Set the sun_path member of struct sockaddr_un.
> +   Copyright (C) 2022 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 <errno.h>
> +#include <string.h>
> +#include <sys/socket.h>
> +#include <sys/un.h>
> +
> +int
> +__sockaddr_un_set (struct sockaddr_un *addr, const char *pathname)
> +{
> +  size_t name_length = strlen (pathname);
> +
> +  /* The kernel supports names of exactly sizeof (addr->sun_path)
> +     bytes, without a null terminator, but userspace does not; see the
> +     SUN_LEN macro.  */
> +  if (name_length >= sizeof (addr->sun_path))
> +    {
> +      __set_errno (EINVAL);     /* Error code used by the kernel.  */
> +      return -1;
> +    }
> +
> +  addr->sun_family = AF_UNIX;
> +  memcpy (addr->sun_path, pathname, name_length + 1);
> +  return 0;
> +}
> diff --git a/socket/tst-sockaddr_un_set.c b/socket/tst-sockaddr_un_set.c
> new file mode 100644
> index 0000000000..29c2a81afd
> --- /dev/null
> +++ b/socket/tst-sockaddr_un_set.c
> @@ -0,0 +1,62 @@
> +/* Test the __sockaddr_un_set function.
> +   Copyright (C) 2022 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/>.  */
> +
> +/* Re-compile the function because the version in libc is not
> +   exported.  */
> +#include "sockaddr_un_set.c"
> +
> +#include <support/check.h>
> +
> +static int
> +do_test (void)
> +{
> +  struct sockaddr_un sun;
> +
> +  memset (&sun, 0xcc, sizeof (sun));
> +  __sockaddr_un_set (&sun, "");
> +  TEST_COMPARE (sun.sun_family, AF_UNIX);
> +  TEST_COMPARE (__sockaddr_un_set (&sun, ""), 0);
> +
> +  memset (&sun, 0xcc, sizeof (sun));
> +  TEST_COMPARE (__sockaddr_un_set (&sun, "/example"), 0);
> +  TEST_COMPARE_STRING (sun.sun_path, "/example");
> +
> +  {
> +    char pathname[108];         /* Length of sun_path (ABI constant).  */
> +    memset (pathname, 'x', sizeof (pathname));
> +    pathname[sizeof (pathname) - 1] = '\0';
> +    memset (&sun, 0xcc, sizeof (sun));
> +    TEST_COMPARE (__sockaddr_un_set (&sun, pathname), 0);
> +    TEST_COMPARE (sun.sun_family, AF_UNIX);
> +    TEST_COMPARE_STRING (sun.sun_path, pathname);
> +  }
> +
> +  {
> +    char pathname[109];
> +    memset (pathname, 'x', sizeof (pathname));
> +    pathname[sizeof (pathname) - 1] = '\0';
> +    memset (&sun, 0xcc, sizeof (sun));
> +    errno = 0;
> +    TEST_COMPARE (__sockaddr_un_set (&sun, pathname), -1);
> +    TEST_COMPARE (errno, EINVAL);
> +  }
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>