[glibc] rt: Replace generic stub of shm_open with the posix version

[glibc] rt: Replace generic stub of shm_open with the posix version

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b7a0bfbd2f3eca602584f51f935599a776784a93

commit b7a0bfbd2f3eca602584f51f935599a776784a93
Author: Florian Weimer <fweimer@redhat.com>
Date:   Mon Jun 21 08:25:15 2021 +0200

    rt: Replace generic stub of shm_open with the posix version
    
    Result of: git mv -f sysdeps/posix/shm_open.c rt
    and manual removal of the _POSIX_MAPPED_FILES preprocessor condition.
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Diff:
---
 rt/shm_open.c            | 34 ++++++++++++++++++++++----
 sysdeps/posix/shm_open.c | 62 ------------------------------------------------
 2 files changed, 29 insertions(+), 67 deletions(-)

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 */