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8b4a118222
Building with -Os produces linknamespace and localplt failures for, among other functions, gnu_dev_major, gnu_dev_minor and gnu_dev_makedev. The issue is that those functions are not inlined when building with -Os. While one could force them to be inlined in that case, it seems more natural to fix this issue similarly to other namespace issues. Thus, this patch makes gnu_dev_* into weak aliases for hidden symbols __gnu_dev_*; __gnu_dev_* are then defined as inlines in the internal include/sys/sysmacros.h, and uses of gnu_dev_* (often via the macros major, minor and makedev) for which there are namespace issues are changed to use __gnu_dev_*; where there are no namespace issues, use of libc_hidden_proto serves to avoid unnecessary local PLT entry use. Tested for x86_64, (a) without -Os, to verify the testsuite continues to pass without problems and that the functions called under their new names continue to be inlined as expected in that case; (b) with -Os, to verify that the linknamespace and localplt failures in question go away (but because of other such failures present, neither of the relevant bugs can yet be closed). [BZ #15105] [BZ #19463] * include/sys/sysmacros.h [!_ISOMAC] (__SYSMACROS_NEED_IMPLEMENTATION): Define macro. [!_SYS_SYSMACROS_H_WRAPPER && !_ISOMAC] (_SYS_SYSMACROS_H_WRAPPER): Likewise. [!_SYS_SYSMACROS_H_WRAPPER && !_ISOMAC] (gnu_dev_major): Use libc_hidden_proto. [!_SYS_SYSMACROS_H_WRAPPER && !_ISOMAC] (gnu_dev_minor): Likewise. [!_SYS_SYSMACROS_H_WRAPPER && !_ISOMAC] (gnu_dev_makedev): Likewise. [!_SYS_SYSMACROS_H_WRAPPER && !_ISOMAC] (__SYSMACROS_DECL_TEMPL): Undefine and redefine to add use __gnu_dev_ prefix. [!_SYS_SYSMACROS_H_WRAPPER && !_ISOMAC] (__SYSMACROS_IMPL_TEMPL): Likewise. [!_SYS_SYSMACROS_H_WRAPPER && !_ISOMAC] (__gnu_dev_major): Declare and define as hidden inline function. [!_SYS_SYSMACROS_H_WRAPPER && !_ISOMAC] (__gnu_dev_minor): Likewise. [!_SYS_SYSMACROS_H_WRAPPER && !_ISOMAC] (__gnu_dev_makedev): Likewise. * misc/makedev.c (OUT_OF_LINE_IMPL_TEMPL): Use __gnu_dev_ prefix. (gnu_dev_major): Use weak_alias and libc_hidden_weak. (gnu_dev_minor): Likewise. (gnu_dev_makedev): Likewise. * csu/check_fds.c (check_one_fd): Use __gnu_dev_makedev instead of makedev. * posix/wordexp.c (exec_comm_child): Likewise. * sysdeps/mach/hurd/xmknodat.c (__xmknodat): Use __gnu_dev_minor instead of minor and __gnu_dev_major instead of major. * sysdeps/unix/sysv/linux/device-nrs.h (DEV_TTY_P): Use __gnu_dev_major instead of major. * sysdeps/unix/sysv/linux/pathconf.c (distinguish_extX): Use __gnu_dev_major instead of gnu_dev_major and __gnu_dev_minor instead of gnu_dev_minor. * sysdeps/unix/sysv/linux/ptsname.c (MASTER_P): Likewise. (SLAVE_P): Likewise. (__ptsname_internal): Use __gnu_dev_minor instead of minor. * sysdeps/unix/sysv/linux/ttyname.h (is_pty): Use __gnu_dev_major instead of major.
98 lines
3.2 KiB
C
98 lines
3.2 KiB
C
/* Copyright (C) 2000-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <fcntl.h>
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#include <paths.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <sys/sysmacros.h>
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/* Try to get a machine dependent instruction which will make the
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program crash. This is used in case everything else fails. */
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#include <abort-instr.h>
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#ifndef ABORT_INSTRUCTION
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/* No such instruction is available. */
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# define ABORT_INSTRUCTION
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#endif
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#include <device-nrs.h>
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#include <not-cancel.h>
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/* Should other OSes (e.g., Hurd) have different versions which can
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be written in a better way? */
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static void
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check_one_fd (int fd, int mode)
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{
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/* Note that fcntl() with this parameter is not a cancellation point. */
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if (__builtin_expect (__libc_fcntl (fd, F_GETFD), 0) == -1
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&& errno == EBADF)
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{
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const char *name;
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dev_t dev;
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/* For writable descriptors we use /dev/full. */
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if ((mode & O_ACCMODE) == O_WRONLY)
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{
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name = _PATH_DEV "full";
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dev = __gnu_dev_makedev (DEV_FULL_MAJOR, DEV_FULL_MINOR);
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}
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else
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{
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name = _PATH_DEVNULL;
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dev = __gnu_dev_makedev (DEV_NULL_MAJOR, DEV_NULL_MINOR);
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}
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/* Something is wrong with this descriptor, it's probably not
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opened. Open /dev/null so that the SUID program we are
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about to start does not accidentally use this descriptor. */
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int nullfd = __open_nocancel (name, mode, 0);
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/* We are very paranoid here. With all means we try to ensure
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that we are actually opening the /dev/null device and nothing
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else.
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Note that the following code assumes that STDIN_FILENO,
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STDOUT_FILENO, STDERR_FILENO are the three lowest file
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decsriptor numbers, in this order. */
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struct stat64 st;
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if (__builtin_expect (nullfd != fd, 0)
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|| __builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0) != 0
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|| __builtin_expect (S_ISCHR (st.st_mode), 1) == 0
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|| st.st_rdev != dev)
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/* We cannot even give an error message here since it would
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run into the same problems. */
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while (1)
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/* Try for ever and ever. */
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ABORT_INSTRUCTION;
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}
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}
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void
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__libc_check_standard_fds (void)
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{
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/* Check all three standard file descriptors. The O_NOFOLLOW flag
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is really paranoid but some people actually are. If /dev/null
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should happen to be a symlink to somewhere else and not the
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device commonly known as "/dev/null" we bail out. */
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check_one_fd (STDIN_FILENO, O_WRONLY | O_NOFOLLOW);
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check_one_fd (STDOUT_FILENO, O_RDONLY | O_NOFOLLOW);
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check_one_fd (STDERR_FILENO, O_RDONLY | O_NOFOLLOW);
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}
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