From e9fed2438a1ff475821864f906286dc58907f06b Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Wed, 3 Feb 2021 08:55:13 -0300 Subject: linux: Require /dev/shm as the shared memory file system Previously, glibc would pick an arbitrary tmpfs file system from /proc/mounts if /dev/shm was not available. This could lead to an unsuitable file system being picked for the backing storage for shm_open, sem_open, and related functions. This patch introduces a new function, __shm_get_name, which builds the file name under the appropriate (now hard-coded) directory. It is called from the various shm_* and sem_* function. Unlike the SHM_GET_NAME macro it replaces, the callers handle the return values and errno updates. shm-directory.c is moved directly into the posix subdirectory because it can be implemented directly using POSIX functionality. It resides in libc because it is needed by both librt and nptl/htl. In the sem_open implementation, tmpfname is initialized directly from a string constant. This happens to remove one alloca call. Checked on x86_64-linux-gnu. --- sysdeps/htl/shm-directory.h | 30 ------------------------------ 1 file changed, 30 deletions(-) delete mode 100644 sysdeps/htl/shm-directory.h (limited to 'sysdeps/htl') diff --git a/sysdeps/htl/shm-directory.h b/sysdeps/htl/shm-directory.h deleted file mode 100644 index 8bfd7287b5..0000000000 --- a/sysdeps/htl/shm-directory.h +++ /dev/null @@ -1,30 +0,0 @@ -/* Header for directory for shm/sem files. libpthread version. - Copyright (C) 2014-2021 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 - . */ - -#ifndef _SHM_DIRECTORY_H - -#include - -/* For libpthread the __shm_directory function lives in libpthread. - We don't want PLT calls from there. But it's also used from - librt, so it cannot just be declared hidden. */ - -#if IS_IN (libpthread) -hidden_proto (__shm_directory) -#endif -#endif /* shm-directory.h */ -- cgit v1.2.3