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Diffstat (limited to 'm4/getcwd-abort-bug.m4')
| -rw-r--r-- | m4/getcwd-abort-bug.m4 | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/m4/getcwd-abort-bug.m4 b/m4/getcwd-abort-bug.m4 new file mode 100644 index 0000000..2174e3f --- /dev/null +++ b/m4/getcwd-abort-bug.m4 @@ -0,0 +1,158 @@ +# serial 16 +# Determine whether getcwd aborts when the length of the working directory +# name is unusually large. Any length between 4k and 16k trigger the bug +# when using glibc-2.4.90-9 or older. + +# Copyright (C) 2006, 2009-2022 Free Software Foundation, Inc. +# This file is free software; the Free Software Foundation +# gives unlimited permission to copy and/or distribute it, +# with or without modifications, as long as this notice is preserved. + +# From Jim Meyering + +# gl_FUNC_GETCWD_ABORT_BUG([ACTION-IF-BUGGY[, ACTION-IF-WORKS]]) +AC_DEFUN([gl_FUNC_GETCWD_ABORT_BUG], +[ + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + AC_CHECK_DECLS_ONCE([getcwd]) + AC_CHECK_HEADERS_ONCE([unistd.h]) + AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ]) + + gl_CHECK_FUNC_GETPAGESIZE + if test $gl_cv_func_getpagesize = yes; then + AC_DEFINE_UNQUOTED([HAVE_GETPAGESIZE], [1], + [Define to 1 if the system has the 'getpagesize' function.]) + fi + + AC_CACHE_CHECK([whether getcwd succeeds when 4k < cwd_length < 16k], + [gl_cv_func_getcwd_succeeds_beyond_4k], + [# Remove any remnants of a previous test. + rm -rf confdir-14B--- + # Arrange for deletion of the temporary directory this test creates. + ac_clean_files="$ac_clean_files confdir-14B---" + dnl Please keep this in sync with tests/test-getcwd.c. + AC_RUN_IFELSE( + [AC_LANG_SOURCE( + [[ +#include <errno.h> +#include <stdlib.h> +#if HAVE_UNISTD_H +# include <unistd.h> +#else /* on Windows with MSVC */ +# include <direct.h> +#endif +#include <string.h> +#include <sys/stat.h> + +]gl_PATHMAX_SNIPPET[ +]GL_MDA_DEFINES[ + +#ifndef S_IRWXU +# define S_IRWXU 0700 +#endif + +/* FIXME: skip the run-test altogether on systems without getpagesize. */ +#if ! HAVE_GETPAGESIZE +# define getpagesize() 0 +#endif + +/* This size is chosen to be larger than PATH_MAX (4k), yet smaller than + the 16kB pagesize on ia64 linux. Those conditions make the code below + trigger a bug in glibc's getcwd implementation before 2.4.90-10. */ +#define TARGET_LEN (5 * 1024) + +int +main () +{ + char *cwd; + size_t initial_cwd_len; + int fail = 0; + + /* The bug is triggered when PATH_MAX < getpagesize (), so skip + this relatively expensive and invasive test if that's not true. */ +#ifdef PATH_MAX + int bug_possible = PATH_MAX < getpagesize (); +#else + int bug_possible = 0; +#endif + if (! bug_possible) + return 0; + + cwd = getcwd (NULL, 0); + if (cwd == NULL) + return 2; + + initial_cwd_len = strlen (cwd); + free (cwd); + + if (1) + { + static char const dir_name[] = "confdir-14B---"; + size_t desired_depth = ((TARGET_LEN - 1 - initial_cwd_len) + / sizeof dir_name); + size_t d; + for (d = 0; d < desired_depth; d++) + { + if (mkdir (dir_name, S_IRWXU) < 0 || chdir (dir_name) < 0) + { + if (! (errno == ERANGE || errno == ENAMETOOLONG + || errno == ENOENT)) + fail = 3; /* Unable to construct deep hierarchy. */ + break; + } + } + + /* If libc has the bug in question, this invocation of getcwd + results in a failed assertion. */ + cwd = getcwd (NULL, 0); + if (cwd == NULL) + fail = 4; /* getcwd didn't assert, but it failed for a long name + where the answer could have been learned. */ + free (cwd); + + /* Call rmdir first, in case the above chdir failed. */ + rmdir (dir_name); + while (0 < d--) + { + if (chdir ("..") < 0) + { + fail = 5; + break; + } + rmdir (dir_name); + } + } + + return fail; +} + ]])], + [gl_cv_func_getcwd_succeeds_beyond_4k=yes], + [dnl An abort will provoke an exit code of something like 134 (128 + 6). + dnl An exit code of 4 can also occur (for example in + dnl musl libc 1.2.2/powerpc64le, NetBSD 9.0, OpenBSD 6.7: + dnl getcwd (NULL, 0) fails rather than returning a string longer than + dnl PATH_MAX. This may be POSIX compliant (in some interpretations of + dnl POSIX). But gnulib's getcwd module wants to provide a non-NULL + dnl value in this case. + ret=$? + if test $ret -ge 128 || test $ret = 4; then + gl_cv_func_getcwd_succeeds_beyond_4k=no + else + gl_cv_func_getcwd_succeeds_beyond_4k=yes + fi + ], + [case "$host_os" in + # Guess no otherwise, even on glibc systems and musl systems. + *) gl_cv_func_getcwd_succeeds_beyond_4k="guessing no" + esac + ]) + ]) + case "$gl_cv_func_getcwd_succeeds_beyond_4k" in + *no) + $1 + ;; + *) + $2 + ;; + esac +]) |