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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 19:37:10 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 19:37:10 +0000
commitc9addba5cc770d2d231b34f6739f32c6be8690f1 (patch)
treec643da154a95a1d163137135050bb47858a1654e /gl/m4/getcwd-path-max.m4
parentInitial commit. (diff)
downloadman-db-c9addba5cc770d2d231b34f6739f32c6be8690f1.tar.xz
man-db-c9addba5cc770d2d231b34f6739f32c6be8690f1.zip
Adding upstream version 2.12.0.upstream/2.12.0
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'gl/m4/getcwd-path-max.m4')
-rw-r--r--gl/m4/getcwd-path-max.m4236
1 files changed, 236 insertions, 0 deletions
diff --git a/gl/m4/getcwd-path-max.m4 b/gl/m4/getcwd-path-max.m4
new file mode 100644
index 0000000..516c078
--- /dev/null
+++ b/gl/m4/getcwd-path-max.m4
@@ -0,0 +1,236 @@
+# serial 25
+# Check for several getcwd bugs with long file names.
+# If so, arrange to compile the wrapper function.
+
+# This is necessary for at least GNU libc on linux-2.4.19 and 2.4.20.
+# I've heard that this is due to a Linux kernel bug, and that it has
+# been fixed between 2.4.21-pre3 and 2.4.21-pre4.
+
+# Copyright (C) 2003-2007, 2009-2023 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
+
+AC_DEFUN([gl_FUNC_GETCWD_PATH_MAX],
+[
+ AC_CHECK_DECLS_ONCE([getcwd])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+ AC_CHECK_HEADERS_ONCE([unistd.h])
+ AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ])
+ AC_CACHE_CHECK([whether getcwd handles long file names properly],
+ [gl_cv_func_getcwd_path_max],
+ [# Arrange for deletion of the temporary directory this test creates.
+ ac_clean_files="$ac_clean_files confdir3"
+ 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
+# include <direct.h>
+#endif
+#include <string.h>
+#include <limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+
+]gl_PATHMAX_SNIPPET[
+
+#ifndef AT_FDCWD
+# define AT_FDCWD 0
+#endif
+#ifdef ENAMETOOLONG
+# define is_ENAMETOOLONG(x) ((x) == ENAMETOOLONG)
+#else
+# define is_ENAMETOOLONG(x) 0
+#endif
+
+/* Use the getcwd function, not any macro. */
+#undef getcwd
+
+]GL_MDA_DEFINES[
+
+#ifndef S_IRWXU
+# define S_IRWXU 0700
+#endif
+
+/* The length of this name must be 8. */
+#define DIR_NAME "confdir3"
+#define DIR_NAME_LEN 8
+#define DIR_NAME_SIZE (DIR_NAME_LEN + 1)
+
+/* The length of "../". */
+#define DOTDOTSLASH_LEN 3
+
+/* Leftover bytes in the buffer, to work around library or OS bugs. */
+#define BUF_SLOP 20
+
+int
+main ()
+{
+#ifndef PATH_MAX
+ /* The Hurd doesn't define this, so getcwd can't exhibit the bug --
+ at least not on a local file system. And if we were to start worrying
+ about remote file systems, we'd have to enable the wrapper function
+ all of the time, just to be safe. That's not worth the cost. */
+ exit (0);
+#elif ((INT_MAX / (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1) \
+ - DIR_NAME_SIZE - BUF_SLOP) \
+ <= PATH_MAX)
+ /* FIXME: Assuming there's a system for which this is true,
+ this should be done in a compile test. */
+ exit (0);
+#else
+ char buf[PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1)
+ + DIR_NAME_SIZE + BUF_SLOP];
+ char *cwd = getcwd (buf, PATH_MAX);
+ size_t initial_cwd_len;
+ size_t cwd_len;
+ int fail = 0;
+ size_t n_chdirs = 0;
+
+ if (cwd == NULL)
+ exit (10);
+
+ cwd_len = initial_cwd_len = strlen (cwd);
+
+ while (1)
+ {
+ size_t dotdot_max = PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN);
+ char *c = NULL;
+
+ cwd_len += DIR_NAME_SIZE;
+ /* If mkdir or chdir fails, it could be that this system cannot create
+ any file with an absolute name longer than PATH_MAX, such as cygwin.
+ If so, leave fail as 0, because the current working directory can't
+ be too long for getcwd if it can't even be created. On Linux with
+ the 9p file system, mkdir fails with error EINVAL when cwd_len gets
+ too long; ignore this failure because the getcwd() system call
+ produces good results whereas the gnulib substitute calls getdents64
+ which fails with error EPROTO.
+ For other errors, be pessimistic and consider that as a failure,
+ too. */
+ if (mkdir (DIR_NAME, S_IRWXU) < 0 || chdir (DIR_NAME) < 0)
+ {
+ if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
+ #ifdef __linux__
+ if (! (errno == EINVAL))
+ #endif
+ fail = 20;
+ break;
+ }
+
+ if (PATH_MAX <= cwd_len && cwd_len < PATH_MAX + DIR_NAME_SIZE)
+ {
+ struct stat sb;
+
+ c = getcwd (buf, PATH_MAX);
+ if (!c && errno == ENOENT)
+ {
+ fail = 11;
+ break;
+ }
+ if (c)
+ {
+ fail = 31;
+ break;
+ }
+ if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
+ {
+ fail = 21;
+ break;
+ }
+
+ /* Our replacement needs to be able to stat() long ../../paths,
+ so generate a path larger than PATH_MAX to check,
+ avoiding the replacement if we can't stat(). */
+ c = getcwd (buf, cwd_len + 1);
+ if (c && !AT_FDCWD && stat (c, &sb) != 0 && is_ENAMETOOLONG (errno))
+ {
+ fail = 32;
+ break;
+ }
+ }
+
+ if (dotdot_max <= cwd_len - initial_cwd_len)
+ {
+ if (dotdot_max + DIR_NAME_SIZE < cwd_len - initial_cwd_len)
+ break;
+ c = getcwd (buf, cwd_len + 1);
+ if (!c)
+ {
+ if (! (errno == ERANGE || errno == ENOENT
+ || is_ENAMETOOLONG (errno)))
+ {
+ fail = 22;
+ break;
+ }
+ if (AT_FDCWD || errno == ERANGE || errno == ENOENT)
+ {
+ fail = 12;
+ break;
+ }
+ }
+ }
+
+ if (c && strlen (c) != cwd_len)
+ {
+ fail = 23;
+ break;
+ }
+ ++n_chdirs;
+ }
+
+ /* Leaving behind such a deep directory is not polite.
+ So clean up here, right away, even though the driving
+ shell script would also clean up. */
+ {
+ size_t i;
+
+ /* Try rmdir first, in case the chdir failed. */
+ rmdir (DIR_NAME);
+ for (i = 0; i <= n_chdirs; i++)
+ {
+ if (chdir ("..") < 0)
+ break;
+ if (rmdir (DIR_NAME) != 0)
+ break;
+ }
+ }
+
+ exit (fail);
+#endif
+}
+ ]])],
+ [gl_cv_func_getcwd_path_max=yes],
+ [case $? in
+ 10|11|12) gl_cv_func_getcwd_path_max='no, but it is partly working';;
+ 31) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
+ 32) gl_cv_func_getcwd_path_max='yes, but with shorter paths';;
+ *) gl_cv_func_getcwd_path_max=no;;
+ esac],
+ [# Cross-compilation guesses:
+ case "$host_os" in
+ aix*) # On AIX, it has the AIX bug.
+ gl_cv_func_getcwd_path_max='guessing no, it has the AIX bug' ;;
+ gnu*) # On Hurd, it is 'yes'.
+ gl_cv_func_getcwd_path_max='guessing yes' ;;
+ linux* | kfreebsd*)
+ # On older Linux+glibc it's 'no, but it is partly working',
+ # on newer Linux+glibc it's 'yes'.
+ # On Linux+musl libc, it's 'no, but it is partly working'.
+ # On kFreeBSD+glibc, it's 'no, but it is partly working'.
+ gl_cv_func_getcwd_path_max='guessing no, but it is partly working' ;;
+ *) # If we don't know, obey --enable-cross-guesses.
+ gl_cv_func_getcwd_path_max="$gl_cross_guess_normal" ;;
+ esac
+ ])
+ ])
+])