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067428c171
This simplifies Emacs a bit, since it no longer needs to worry about closing file descriptors by hand in some cases. It also fixes some unlikely races. Not all such races, as libraries often open files internally without setting close-on-exec, but it's an improvement. * admin/merge-gnulib (GNULIB_MODULES): Add fcntl, pipe2. (GNULIB_TOOL_FLAGS): Avoid binary-io, close. Do not avoid fcntl. * configure.ac (mkostemp): New function to check for. (PTY_OPEN): Pass O_CLOEXEC to posix_openpt. * lib/fcntl.c, lib/getdtablesize.c, lib/pipe2.c, m4/fcntl.m4: * m4/getdtablesize.m4, m4/pipe2.m4: New files, taken from gnulib. * lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate. * nt/gnulib.mk: Remove empty gl_GNULIB_ENABLED_verify section; otherwise, gnulib-tool complains given close-on-exec changes. * nt/inc/ms-w32.h (pipe): Remove. * nt/mingw-cfg.site (ac_cv_func_fcntl, gl_cv_func_fcntl_f_dupfd_cloexec) (gl_cv_func_fcntl_f_dupfd_works, ac_cv_func_pipe2): New vars. * src/alloc.c (valid_pointer_p) [!WINDOWSNT]: * src/callproc.c (Fcall_process) [!MSDOS]: * src/emacs.c (main) [!DOS_NT]: * src/nsterm.m (ns_term_init): * src/process.c (create_process): Use 'pipe2' with O_CLOEXEC instead of 'pipe'. * src/emacs.c (Fcall_process_region) [HAVE_MKOSTEMP]: * src/filelock.c (create_lock_file) [HAVE_MKOSTEMP]: Prefer mkostemp with O_CLOEXEC to mkstemp. * src/callproc.c (relocate_fd) [!WINDOWSNT]: * src/emacs.c (main): Use F_DUPFD_CLOEXEC, not plain F_DUPFD. No need to use fcntl (..., F_SETFD, FD_CLOEXEC), since we're now using pipe2. * src/filelock.c (create_lock_file) [! HAVE_MKOSTEMP]: Make the resulting file descriptor close-on-exec. * src/lisp.h, src/lread.c, src/process.c (close_load_descs, close_process_descs): * src/lread.c (load_descriptor_list, load_descriptor_unwind): Remove; no longer needed. All uses removed. * src/process.c (SOCK_CLOEXEC): Define to 0 if not supplied by system. (close_on_exec, accept4, process_socket) [!SOCK_CLOEXEC]: New functions. (socket) [!SOCK_CLOEXEC]: Supply a substitute. (Fmake_network_process, Fnetwork_interface_list): (Fnetwork_interface_info, server_accept_connection): Make newly-created socket close-on-exec. * src/sysdep.c (emacs_open, emacs_fopen): Make new-created descriptor close-on-exec. * src/w32.c (fcntl): Support F_DUPFD_CLOEXEC well enough for Emacs. * src/w32.c, src/w32.h (pipe2): Rename from 'pipe', with new flags arg. Fixes: debbugs:14803
96 lines
3.0 KiB
Plaintext
96 lines
3.0 KiB
Plaintext
# fcntl.m4 serial 5
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dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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# For now, this module ensures that fcntl()
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# - supports F_DUPFD correctly
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# - supports or emulates F_DUPFD_CLOEXEC
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# - supports F_GETFD
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# Still to be ported to mingw:
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# - F_SETFD
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# - F_GETFL, F_SETFL
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# - F_GETOWN, F_SETOWN
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# - F_GETLK, F_SETLK, F_SETLKW
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AC_DEFUN([gl_FUNC_FCNTL],
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[
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dnl Persuade glibc to expose F_DUPFD_CLOEXEC.
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AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
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AC_REQUIRE([AC_CANONICAL_HOST])
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AC_CHECK_FUNCS_ONCE([fcntl])
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if test $ac_cv_func_fcntl = no; then
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gl_REPLACE_FCNTL
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else
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dnl cygwin 1.5.x F_DUPFD has wrong errno, and allows negative target
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dnl haiku alpha 2 F_DUPFD has wrong errno
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AC_CACHE_CHECK([whether fcntl handles F_DUPFD correctly],
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[gl_cv_func_fcntl_f_dupfd_works],
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[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
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#include <fcntl.h>
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#include <errno.h>
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]], [[int result = 0;
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if (fcntl (0, F_DUPFD, -1) != -1) result |= 1;
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if (errno != EINVAL) result |= 2;
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return result;
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]])],
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[gl_cv_func_fcntl_f_dupfd_works=yes],
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[gl_cv_func_fcntl_f_dupfd_works=no],
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[# Guess that it works on glibc systems
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case $host_os in #((
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*-gnu*) gl_cv_func_fcntl_f_dupfd_works="guessing yes";;
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*) gl_cv_func_fcntl_f_dupfd_works="guessing no";;
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esac])])
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case $gl_cv_func_fcntl_f_dupfd_works in
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*yes) ;;
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*) gl_REPLACE_FCNTL
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AC_DEFINE([FCNTL_DUPFD_BUGGY], [1], [Define this to 1 if F_DUPFD
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behavior does not match POSIX]) ;;
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esac
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dnl Many systems lack F_DUPFD_CLOEXEC
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AC_CACHE_CHECK([whether fcntl understands F_DUPFD_CLOEXEC],
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[gl_cv_func_fcntl_f_dupfd_cloexec],
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[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
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#include <fcntl.h>
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#ifndef F_DUPFD_CLOEXEC
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choke me
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#endif
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]])],
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[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
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#ifdef __linux__
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/* The Linux kernel only added F_DUPFD_CLOEXEC in 2.6.24, so we always replace
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it to support the semantics on older kernels that failed with EINVAL. */
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choke me
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#endif
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]])],
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[gl_cv_func_fcntl_f_dupfd_cloexec=yes],
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[gl_cv_func_fcntl_f_dupfd_cloexec="needs runtime check"])],
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[gl_cv_func_fcntl_f_dupfd_cloexec=no])])
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if test "$gl_cv_func_fcntl_f_dupfd_cloexec" != yes; then
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gl_REPLACE_FCNTL
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dnl No witness macro needed for this bug.
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fi
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fi
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dnl Replace fcntl() for supporting the gnulib-defined fchdir() function,
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dnl to keep fchdir's bookkeeping up-to-date.
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m4_ifdef([gl_FUNC_FCHDIR], [
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gl_TEST_FCHDIR
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if test $HAVE_FCHDIR = 0; then
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gl_REPLACE_FCNTL
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fi
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])
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])
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AC_DEFUN([gl_REPLACE_FCNTL],
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[
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AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
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AC_CHECK_FUNCS_ONCE([fcntl])
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if test $ac_cv_func_fcntl = no; then
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HAVE_FCNTL=0
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else
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REPLACE_FCNTL=1
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fi
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])
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