115 lines
4 KiB
Text
115 lines
4 KiB
Text
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# readlink.m4 serial 16
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dnl Copyright (C) 2003, 2007, 2009-2021 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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AC_DEFUN([gl_FUNC_READLINK],
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[
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AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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AC_CHECK_FUNCS_ONCE([readlink])
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if test $ac_cv_func_readlink = no; then
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HAVE_READLINK=0
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else
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AC_CACHE_CHECK([whether readlink signature is correct],
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[gl_cv_decl_readlink_works],
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[AC_COMPILE_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <unistd.h>
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/* Cause compilation failure if original declaration has wrong type. */
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ssize_t readlink (const char *, char *, size_t);]])],
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[gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
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dnl Solaris 9 ignores trailing slash.
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dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
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AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
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[gl_cv_func_readlink_trailing_slash],
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[# We have readlink, so assume ln -s works.
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ln -s conftest.no-such conftest.link
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ln -s conftest.link conftest.lnk2
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AC_RUN_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <unistd.h>
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]], [[char buf[20];
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return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
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[gl_cv_func_readlink_trailing_slash=yes],
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[gl_cv_func_readlink_trailing_slash=no],
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[case "$host_os" in
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# Guess yes on Linux or glibc systems.
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linux-* | linux | *-gnu* | gnu*)
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gl_cv_func_readlink_trailing_slash="guessing yes" ;;
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# Guess no on AIX or HP-UX.
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aix* | hpux*)
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gl_cv_func_readlink_trailing_slash="guessing no" ;;
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# If we don't know, obey --enable-cross-guesses.
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*)
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gl_cv_func_readlink_trailing_slash="$gl_cross_guess_normal" ;;
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esac
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])
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rm -f conftest.link conftest.lnk2])
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case "$gl_cv_func_readlink_trailing_slash" in
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*yes)
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if test "$gl_cv_decl_readlink_works" != yes; then
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REPLACE_READLINK=1
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fi
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;;
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*)
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AC_DEFINE([READLINK_TRAILING_SLASH_BUG], [1], [Define to 1 if readlink
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fails to recognize a trailing slash.])
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REPLACE_READLINK=1
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;;
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esac
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AC_CACHE_CHECK([whether readlink truncates results correctly],
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[gl_cv_func_readlink_truncate],
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[# We have readlink, so assume ln -s works.
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ln -s ab conftest.link
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AC_RUN_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <unistd.h>
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]], [[char c;
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return readlink ("conftest.link", &c, 1) != 1;]])],
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[gl_cv_func_readlink_truncate=yes],
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[gl_cv_func_readlink_truncate=no],
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[case "$host_os" in
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# Guess yes on Linux or glibc systems.
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linux-* | linux | *-gnu* | gnu*)
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gl_cv_func_readlink_truncate="guessing yes" ;;
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# Guess no on AIX or HP-UX.
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aix* | hpux*)
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gl_cv_func_readlink_truncate="guessing no" ;;
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# If we don't know, obey --enable-cross-guesses.
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*)
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gl_cv_func_readlink_truncate="$gl_cross_guess_normal" ;;
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esac
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])
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rm -f conftest.link conftest.lnk2])
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case $gl_cv_func_readlink_truncate in
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*yes)
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if test "$gl_cv_decl_readlink_works" != yes; then
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REPLACE_READLINK=1
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fi
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;;
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*)
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AC_DEFINE([READLINK_TRUNCATE_BUG], [1], [Define to 1 if readlink
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sets errno instead of truncating a too-long link.])
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REPLACE_READLINK=1
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;;
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esac
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fi
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])
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# Like gl_FUNC_READLINK, except prepare for separate compilation
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# (no REPLACE_READLINK, no AC_LIBOBJ).
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AC_DEFUN([gl_FUNC_READLINK_SEPARATE],
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[
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AC_CHECK_FUNCS_ONCE([readlink])
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gl_PREREQ_READLINK
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])
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# Prerequisites of lib/readlink.c.
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AC_DEFUN([gl_PREREQ_READLINK],
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[
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:
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])
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