1# serial 11 2# Determine whether getcwd aborts when the length of the working directory 3# name is unusually large. Any length between 4k and 16k trigger the bug 4# when using glibc-2.4.90-9 or older. 5 6# Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc. 7# This file is free software; the Free Software Foundation 8# gives unlimited permission to copy and/or distribute it, 9# with or without modifications, as long as this notice is preserved. 10 11# From Jim Meyering 12 13# gl_FUNC_GETCWD_ABORT_BUG([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]]) 14AC_DEFUN([gl_FUNC_GETCWD_ABORT_BUG], 15[ 16 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles 17 AC_CHECK_DECLS_ONCE([getcwd]) 18 AC_CHECK_HEADERS_ONCE([unistd.h]) 19 AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ]) 20 21 gl_CHECK_FUNC_GETPAGESIZE 22 if test $gl_cv_func_getpagesize = yes; then 23 AC_DEFINE_UNQUOTED([HAVE_GETPAGESIZE], [1], 24 [Define to 1 if the system has the 'getpagesize' function.]) 25 fi 26 27 AC_CACHE_CHECK([whether getcwd aborts when 4k < cwd_length < 16k], 28 [gl_cv_func_getcwd_abort_bug], 29 [# Remove any remnants of a previous test. 30 rm -rf confdir-14B--- 31 # Arrange for deletion of the temporary directory this test creates. 32 ac_clean_files="$ac_clean_files confdir-14B---" 33 dnl Please keep this in sync with tests/test-getcwd.c. 34 AC_RUN_IFELSE( 35 [AC_LANG_SOURCE( 36 [[ 37#include <errno.h> 38#include <stdlib.h> 39#if HAVE_UNISTD_H 40# include <unistd.h> 41#else /* on Windows with MSVC */ 42# include <direct.h> 43#endif 44#include <string.h> 45#include <sys/stat.h> 46 47]gl_PATHMAX_SNIPPET[ 48 49/* Don't get link errors because mkdir is redefined to rpl_mkdir. */ 50#undef mkdir 51 52#ifndef S_IRWXU 53# define S_IRWXU 0700 54#endif 55 56/* FIXME: skip the run-test altogether on systems without getpagesize. */ 57#if ! HAVE_GETPAGESIZE 58# define getpagesize() 0 59#endif 60 61/* This size is chosen to be larger than PATH_MAX (4k), yet smaller than 62 the 16kB pagesize on ia64 linux. Those conditions make the code below 63 trigger a bug in glibc's getcwd implementation before 2.4.90-10. */ 64#define TARGET_LEN (5 * 1024) 65 66int 67main () 68{ 69 char *cwd; 70 size_t initial_cwd_len; 71 int fail = 0; 72 73 /* The bug is triggered when PATH_MAX < getpagesize (), so skip 74 this relatively expensive and invasive test if that's not true. */ 75#ifdef PATH_MAX 76 int bug_possible = PATH_MAX < getpagesize (); 77#else 78 int bug_possible = 0; 79#endif 80 if (! bug_possible) 81 return 0; 82 83 cwd = getcwd (NULL, 0); 84 if (cwd == NULL) 85 return 2; 86 87 initial_cwd_len = strlen (cwd); 88 free (cwd); 89 90 if (1) 91 { 92 static char const dir_name[] = "confdir-14B---"; 93 size_t desired_depth = ((TARGET_LEN - 1 - initial_cwd_len) 94 / sizeof dir_name); 95 size_t d; 96 for (d = 0; d < desired_depth; d++) 97 { 98 if (mkdir (dir_name, S_IRWXU) < 0 || chdir (dir_name) < 0) 99 { 100 if (! (errno == ERANGE || errno == ENAMETOOLONG 101 || errno == ENOENT)) 102 fail = 3; /* Unable to construct deep hierarchy. */ 103 break; 104 } 105 } 106 107 /* If libc has the bug in question, this invocation of getcwd 108 results in a failed assertion. */ 109 cwd = getcwd (NULL, 0); 110 if (cwd == NULL) 111 fail = 4; /* getcwd didn't assert, but it failed for a long name 112 where the answer could have been learned. */ 113 free (cwd); 114 115 /* Call rmdir first, in case the above chdir failed. */ 116 rmdir (dir_name); 117 while (0 < d--) 118 { 119 if (chdir ("..") < 0) 120 { 121 fail = 5; 122 break; 123 } 124 rmdir (dir_name); 125 } 126 } 127 128 return fail; 129} 130 ]])], 131 [gl_cv_func_getcwd_abort_bug=no], 132 [dnl An abort will provoke an exit code of something like 134 (128 + 6). 133 dnl An exit code of 4 can also occur (in OpenBSD 4.9, NetBSD 5.1 for 134 dnl example): getcwd (NULL, 0) fails rather than returning a string 135 dnl longer than PATH_MAX. This may be POSIX compliant (in some 136 dnl interpretations of POSIX). But gnulib's getcwd module wants to 137 dnl provide a non-NULL value in this case. 138 ret=$? 139 if test $ret -ge 128 || test $ret = 4; then 140 gl_cv_func_getcwd_abort_bug=yes 141 else 142 gl_cv_func_getcwd_abort_bug=no 143 fi 144 ], 145 [case "$host_os" in 146 # Guess no on musl systems. 147 *-musl*) gl_cv_func_getcwd_abort_bug="guessing no" ;; 148 # Guess yes otherwise, even on glibc systems. 149 *) gl_cv_func_getcwd_abort_bug="guessing yes" 150 esac 151 ]) 152 ]) 153 case "$gl_cv_func_getcwd_abort_bug" in 154 *yes) 155 $1 156 ;; 157 *) 158 $2 159 ;; 160 esac 161]) 162