| 1 | # readlink.m4 serial 16
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| 2 | dnl Copyright (C) 2003, 2007, 2009-2022 Free Software Foundation, Inc.
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| 3 | dnl This file is free software; the Free Software Foundation
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| 4 | dnl gives unlimited permission to copy and/or distribute it,
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| 5 | dnl with or without modifications, as long as this notice is preserved.
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| 6 |
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| 7 | AC_DEFUN([gl_FUNC_READLINK],
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| 8 | [
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| 9 | AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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| 10 | AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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| 11 | AC_CHECK_FUNCS_ONCE([readlink])
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| 12 | if test $ac_cv_func_readlink = no; then
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| 13 | HAVE_READLINK=0
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| 14 | else
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| 15 | AC_CACHE_CHECK([whether readlink signature is correct],
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| 16 | [gl_cv_decl_readlink_works],
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| 17 | [AC_COMPILE_IFELSE(
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| 18 | [AC_LANG_PROGRAM(
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| 19 | [[#include <unistd.h>
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| 20 | /* Cause compilation failure if original declaration has wrong type. */
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| 21 | ssize_t readlink (const char *, char *, size_t);]])],
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| 22 | [gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
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| 23 | dnl Solaris 9 ignores trailing slash.
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| 24 | dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
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| 25 | AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
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| 26 | [gl_cv_func_readlink_trailing_slash],
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| 27 | [# We have readlink, so assume ln -s works.
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| 28 | ln -s conftest.no-such conftest.link
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| 29 | ln -s conftest.link conftest.lnk2
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| 30 | AC_RUN_IFELSE(
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| 31 | [AC_LANG_PROGRAM(
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| 32 | [[#include <unistd.h>
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| 33 | ]], [[char buf[20];
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| 34 | return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
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| 35 | [gl_cv_func_readlink_trailing_slash=yes],
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| 36 | [gl_cv_func_readlink_trailing_slash=no],
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| 37 | [case "$host_os" in
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| 38 | # Guess yes on Linux or glibc systems.
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| 39 | linux-* | linux | *-gnu* | gnu*)
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| 40 | gl_cv_func_readlink_trailing_slash="guessing yes" ;;
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| 41 | # Guess no on AIX or HP-UX.
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| 42 | aix* | hpux*)
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| 43 | gl_cv_func_readlink_trailing_slash="guessing no" ;;
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| 44 | # If we don't know, obey --enable-cross-guesses.
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| 45 | *)
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| 46 | gl_cv_func_readlink_trailing_slash="$gl_cross_guess_normal" ;;
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| 47 | esac
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| 48 | ])
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| 49 | rm -f conftest.link conftest.lnk2])
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| 50 | case "$gl_cv_func_readlink_trailing_slash" in
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| 51 | *yes)
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| 52 | if test "$gl_cv_decl_readlink_works" != yes; then
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| 53 | REPLACE_READLINK=1
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| 54 | fi
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| 55 | ;;
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| 56 | *)
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| 57 | AC_DEFINE([READLINK_TRAILING_SLASH_BUG], [1], [Define to 1 if readlink
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| 58 | fails to recognize a trailing slash.])
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| 59 | REPLACE_READLINK=1
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| 60 | ;;
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| 61 | esac
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| 62 |
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| 63 | AC_CACHE_CHECK([whether readlink truncates results correctly],
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| 64 | [gl_cv_func_readlink_truncate],
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| 65 | [# We have readlink, so assume ln -s works.
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| 66 | ln -s ab conftest.link
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| 67 | AC_RUN_IFELSE(
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| 68 | [AC_LANG_PROGRAM(
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| 69 | [[#include <unistd.h>
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| 70 | ]], [[char c;
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| 71 | return readlink ("conftest.link", &c, 1) != 1;]])],
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| 72 | [gl_cv_func_readlink_truncate=yes],
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| 73 | [gl_cv_func_readlink_truncate=no],
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| 74 | [case "$host_os" in
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| 75 | # Guess yes on Linux or glibc systems.
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| 76 | linux-* | linux | *-gnu* | gnu*)
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| 77 | gl_cv_func_readlink_truncate="guessing yes" ;;
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| 78 | # Guess no on AIX or HP-UX.
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| 79 | aix* | hpux*)
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| 80 | gl_cv_func_readlink_truncate="guessing no" ;;
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| 81 | # If we don't know, obey --enable-cross-guesses.
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| 82 | *)
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| 83 | gl_cv_func_readlink_truncate="$gl_cross_guess_normal" ;;
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| 84 | esac
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| 85 | ])
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| 86 | rm -f conftest.link conftest.lnk2])
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| 87 | case $gl_cv_func_readlink_truncate in
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| 88 | *yes)
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| 89 | if test "$gl_cv_decl_readlink_works" != yes; then
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| 90 | REPLACE_READLINK=1
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| 91 | fi
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| 92 | ;;
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| 93 | *)
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| 94 | AC_DEFINE([READLINK_TRUNCATE_BUG], [1], [Define to 1 if readlink
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| 95 | sets errno instead of truncating a too-long link.])
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| 96 | REPLACE_READLINK=1
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| 97 | ;;
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| 98 | esac
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| 99 | fi
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| 100 | ])
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| 101 |
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| 102 | # Like gl_FUNC_READLINK, except prepare for separate compilation
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| 103 | # (no REPLACE_READLINK, no AC_LIBOBJ).
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| 104 | AC_DEFUN([gl_FUNC_READLINK_SEPARATE],
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| 105 | [
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| 106 | AC_CHECK_FUNCS_ONCE([readlink])
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| 107 | gl_PREREQ_READLINK
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| 108 | ])
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| 109 |
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| 110 | # Prerequisites of lib/readlink.c.
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| 111 | AC_DEFUN([gl_PREREQ_READLINK],
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| 112 | [
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| 113 | :
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| 114 | ])
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