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-rw-r--r--m4/getcwd-abort-bug.m4158
1 files changed, 158 insertions, 0 deletions
diff --git a/m4/getcwd-abort-bug.m4 b/m4/getcwd-abort-bug.m4
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+# 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
+])