| 1 | # fcntl.m4 serial 5
|
|---|
| 2 | dnl Copyright (C) 2009-2012 Free Software Foundation, Inc.
|
|---|
| 3 | dnl This file is free software; the Free Software Foundation
|
|---|
| 4 | dnl gives unlimited permission to copy and/or distribute it,
|
|---|
| 5 | dnl with or without modifications, as long as this notice is preserved.
|
|---|
| 6 |
|
|---|
| 7 | # For now, this module ensures that fcntl()
|
|---|
| 8 | # - supports F_DUPFD correctly
|
|---|
| 9 | # - supports or emulates F_DUPFD_CLOEXEC
|
|---|
| 10 | # - supports F_GETFD
|
|---|
| 11 | # Still to be ported to mingw:
|
|---|
| 12 | # - F_SETFD
|
|---|
| 13 | # - F_GETFL, F_SETFL
|
|---|
| 14 | # - F_GETOWN, F_SETOWN
|
|---|
| 15 | # - F_GETLK, F_SETLK, F_SETLKW
|
|---|
| 16 | AC_DEFUN([gl_FUNC_FCNTL],
|
|---|
| 17 | [
|
|---|
| 18 | dnl Persuade glibc to expose F_DUPFD_CLOEXEC.
|
|---|
| 19 | AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
|
|---|
| 20 | AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
|
|---|
| 21 | AC_REQUIRE([AC_CANONICAL_HOST])
|
|---|
| 22 | AC_CHECK_FUNCS_ONCE([fcntl])
|
|---|
| 23 | if test $ac_cv_func_fcntl = no; then
|
|---|
| 24 | gl_REPLACE_FCNTL
|
|---|
| 25 | else
|
|---|
| 26 | dnl cygwin 1.5.x F_DUPFD has wrong errno, and allows negative target
|
|---|
| 27 | dnl haiku alpha 2 F_DUPFD has wrong errno
|
|---|
| 28 | AC_CACHE_CHECK([whether fcntl handles F_DUPFD correctly],
|
|---|
| 29 | [gl_cv_func_fcntl_f_dupfd_works],
|
|---|
| 30 | [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
|
|---|
| 31 | #include <fcntl.h>
|
|---|
| 32 | #include <errno.h>
|
|---|
| 33 | ]], [[int result = 0;
|
|---|
| 34 | if (fcntl (0, F_DUPFD, -1) != -1) result |= 1;
|
|---|
| 35 | if (errno != EINVAL) result |= 2;
|
|---|
| 36 | return result;
|
|---|
| 37 | ]])],
|
|---|
| 38 | [gl_cv_func_fcntl_f_dupfd_works=yes],
|
|---|
| 39 | [gl_cv_func_fcntl_f_dupfd_works=no],
|
|---|
| 40 | [# Guess that it works on glibc systems
|
|---|
| 41 | case $host_os in #((
|
|---|
| 42 | *-gnu*) gl_cv_func_fcntl_f_dupfd_works="guessing yes";;
|
|---|
| 43 | *) gl_cv_func_fcntl_f_dupfd_works="guessing no";;
|
|---|
| 44 | esac])])
|
|---|
| 45 | case $gl_cv_func_fcntl_f_dupfd_works in
|
|---|
| 46 | *yes) ;;
|
|---|
| 47 | *) gl_REPLACE_FCNTL
|
|---|
| 48 | AC_DEFINE([FCNTL_DUPFD_BUGGY], [1], [Define this to 1 if F_DUPFD
|
|---|
| 49 | behavior does not match POSIX]) ;;
|
|---|
| 50 | esac
|
|---|
| 51 |
|
|---|
| 52 | dnl Many systems lack F_DUPFD_CLOEXEC
|
|---|
| 53 | AC_CACHE_CHECK([whether fcntl understands F_DUPFD_CLOEXEC],
|
|---|
| 54 | [gl_cv_func_fcntl_f_dupfd_cloexec],
|
|---|
| 55 | [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
|
|---|
| 56 | #include <fcntl.h>
|
|---|
| 57 | #ifndef F_DUPFD_CLOEXEC
|
|---|
| 58 | choke me
|
|---|
| 59 | #endif
|
|---|
| 60 | ]])],
|
|---|
| 61 | [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
|
|---|
| 62 | #ifdef __linux__
|
|---|
| 63 | /* The Linux kernel only added F_DUPFD_CLOEXEC in 2.6.24, so we always replace
|
|---|
| 64 | it to support the semantics on older kernels that failed with EINVAL. */
|
|---|
| 65 | choke me
|
|---|
| 66 | #endif
|
|---|
| 67 | ]])],
|
|---|
| 68 | [gl_cv_func_fcntl_f_dupfd_cloexec=yes],
|
|---|
| 69 | [gl_cv_func_fcntl_f_dupfd_cloexec="needs runtime check"])],
|
|---|
| 70 | [gl_cv_func_fcntl_f_dupfd_cloexec=no])])
|
|---|
| 71 | if test "$gl_cv_func_fcntl_f_dupfd_cloexec" != yes; then
|
|---|
| 72 | gl_REPLACE_FCNTL
|
|---|
| 73 | dnl No witness macro needed for this bug.
|
|---|
| 74 | fi
|
|---|
| 75 | fi
|
|---|
| 76 | dnl Replace fcntl() for supporting the gnulib-defined fchdir() function,
|
|---|
| 77 | dnl to keep fchdir's bookkeeping up-to-date.
|
|---|
| 78 | m4_ifdef([gl_FUNC_FCHDIR], [
|
|---|
| 79 | gl_TEST_FCHDIR
|
|---|
| 80 | if test $HAVE_FCHDIR = 0; then
|
|---|
| 81 | gl_REPLACE_FCNTL
|
|---|
| 82 | fi
|
|---|
| 83 | ])
|
|---|
| 84 | ])
|
|---|
| 85 |
|
|---|
| 86 | AC_DEFUN([gl_REPLACE_FCNTL],
|
|---|
| 87 | [
|
|---|
| 88 | AC_REQUIRE([gl_FCNTL_H_DEFAULTS])
|
|---|
| 89 | AC_CHECK_FUNCS_ONCE([fcntl])
|
|---|
| 90 | if test $ac_cv_func_fcntl = no; then
|
|---|
| 91 | HAVE_FCNTL=0
|
|---|
| 92 | else
|
|---|
| 93 | REPLACE_FCNTL=1
|
|---|
| 94 | fi
|
|---|
| 95 | ])
|
|---|
