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607449506f
The function closes all open file descriptors greater than or equal to input argument. Negative values are clamped to 0, i.e, it will close all file descriptors. As indicated by the bug report, this is a common symbol provided by different systems (Solaris, OpenBSD, NetBSD, FreeBSD) and, although its has inherent issues with not taking in consideration internal libc file descriptors (such as syslog), this is also a common feature used in multiple projects [1][2][3][4][5]. The Linux fallback implementation iterates over /proc and close all file descriptors sequentially. Although it was raised the questioning whether getdents on /proc/self/fd might return disjointed entries when file descriptor are closed; it does not seems the case on my testing on multiple kernel (v4.18, v5.4, v5.9) and the same strategy is used on different projects [1][2][3][5]. Also, the interface is set a fail-safe meaning that a failure in the fallback results in a process abort. Checked on x86_64-linux-gnu and i686-linux-gnu on kernel 5.11 and 4.15. [1]5238e95759/src/basic/fd-util.c (L217)[2]ddf4b77e11/src/lxc/start.c (L236)[3]9e4f2f3a6b/Modules/_posixsubprocess.c (L220)[4]5f47c0613e/src/libstd/sys/unix/process2.rs (L303-L308)[5] https://github.com/openjdk/jdk/blob/master/src/java.base/unix/native/libjava/childproc.c#L82
153 lines
5.4 KiB
Makefile
153 lines
5.4 KiB
Makefile
# Copyright (C) 1992-2021 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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# <https://www.gnu.org/licenses/>.
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#
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# Sub-makefile for I/O portion of the library.
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#
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subdir := io
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include ../Makeconfig
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headers := sys/stat.h bits/stat.h sys/statfs.h bits/statfs.h sys/vfs.h \
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sys/statvfs.h bits/statvfs.h fcntl.h sys/fcntl.h bits/fcntl.h \
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poll.h sys/poll.h bits/poll.h bits/fcntl2.h bits/poll2.h \
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bits/statx.h bits/statx-generic.h bits/types/struct_statx.h \
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bits/types/struct_statx_timestamp.h \
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utime.h ftw.h fts.h sys/sendfile.h
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routines := \
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utime \
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mkfifo mkfifoat \
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stat fstat lstat stat64 fstat64 lstat64 fstatat fstatat64 \
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statx \
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mknod mknodat \
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statfs fstatfs statfs64 fstatfs64 \
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statvfs fstatvfs statvfs64 fstatvfs64 \
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umask chmod fchmod lchmod fchmodat \
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mkdir mkdirat \
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open open_2 open64 open64_2 openat openat_2 openat64 openat64_2 \
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read write lseek lseek64 access euidaccess faccessat \
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fcntl fcntl64 flock lockf lockf64 \
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close dup dup2 dup3 pipe pipe2 \
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creat creat64 \
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chdir fchdir \
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getcwd getwd getdirname \
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chown fchown lchown fchownat \
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ttyname ttyname_r isatty \
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link linkat symlink symlinkat readlink readlinkat \
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unlink unlinkat rmdir \
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ftw ftw64 fts fts64 poll ppoll \
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posix_fadvise posix_fadvise64 \
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posix_fallocate posix_fallocate64 \
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sendfile sendfile64 copy_file_range \
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utimensat futimens file_change_detection \
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fts64-time64 \
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ftw64-time64 \
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closefrom
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others := pwd
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test-srcs := ftwtest ftwtest-time64
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tests := test-utime test-stat test-stat2 test-lfs tst-getcwd \
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tst-fcntl bug-ftw1 bug-ftw2 bug-ftw3 bug-ftw4 tst-statvfs \
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tst-openat tst-unlinkat tst-fstatat tst-futimesat \
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tst-renameat tst-fchownat tst-fchmodat tst-faccessat \
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tst-symlinkat tst-linkat tst-readlinkat tst-mkdirat \
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tst-mknodat tst-mkfifoat tst-ttyname_r bug-ftw5 \
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tst-posix_fallocate tst-posix_fallocate64 \
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tst-fts tst-fts-lfs tst-open-tmpfile \
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tst-copy_file_range tst-getcwd-abspath tst-lockf \
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tst-ftw-lnk tst-lchmod \
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tst-ftw-bz26353 tst-stat tst-stat-lfs \
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tst-utime \
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tst-utimes \
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tst-futimes \
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tst-lutimes \
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tst-futimens \
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tst-utimensat \
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tst-closefrom \
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tests-time64 := \
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tst-futimens-time64 \
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tst-futimes-time64\
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tst-fts-time64 \
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tst-lutimes-time64 \
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tst-stat-time64 \
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tst-futimesat-time64 \
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tst-utime-time64 \
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tst-utimensat-time64 \
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tst-utimes-time64 \
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# Likewise for statx, but we do not need static linking here.
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tests-internal += tst-statx tst-file_change_detection
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tests-static += tst-statx
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ifeq ($(run-built-tests),yes)
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tests-special += $(objpfx)ftwtest.out \
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$(objpfx)ftwtest-time64.out
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endif
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include ../Rules
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CFLAGS-open.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-open64.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-creat.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-creat64.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-fcntl.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-fcntl64.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-poll.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-ppoll.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-lockf.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-lockf64.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-statfs.c += -fexceptions
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CFLAGS-fstatfs.c += -fexceptions
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CFLAGS-statvfs.c += -fexceptions
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CFLAGS-fstatvfs.c += -fexceptions
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CFLAGS-fts.c += -Wno-uninitialized $(uses-callbacks) -fexceptions
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CFLAGS-fts64.c += -Wno-uninitialized $(uses-callbacks) -fexceptions
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CFLAGS-fts64-time64.c += -Wno-uninitialized $(uses-callbacks) -fexceptions
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CFLAGS-ftw.c += $(uses-callbacks) -fexceptions
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CFLAGS-ftw64.c += $(uses-callbacks) -fexceptions
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CFLAGS-ftw64-time64.c += $(uses-callbacks) -fexceptions
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CFLAGS-posix_fallocate.c += -fexceptions
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CFLAGS-posix_fallocate64.c += -fexceptions
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CFLAGS-fallocate.c += -fexceptions
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CFLAGS-fallocate64.c += -fexceptions
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CFLAGS-read.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-write.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-close.c += -fexceptions -fasynchronous-unwind-tables
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CFLAGS-test-stat.c += -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE
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CFLAGS-test-lfs.c += -D_LARGEFILE64_SOURCE
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test-stat2-ARGS = Makefile . $(objpfx)test-stat2
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tst-statvfs-ARGS = $(objpfx)tst-statvfs tst-statvfs.c /tmp
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tst-open-tmpfile-ARGS = --test-dir=$(objpfx)
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CFLAGS-ftwtest-time64.c += -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64
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ifeq ($(run-built-tests),yes)
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$(objpfx)ftwtest.out: ftwtest-sh $(objpfx)ftwtest
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$(SHELL) $< $(common-objpfx) '$(test-program-cmd)' > $@; \
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$(evaluate-test)
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$(objpfx)ftwtest-time64.out: ftwtest-sh $(objpfx)ftwtest-time64
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$(SHELL) $< $(common-objpfx) '$(test-program-cmd)' > $@; \
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$(evaluate-test)
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endif
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