tar-1.29HEADtar-1.29master

1 files changed, 217 insertions, 0 deletions

diff --git a/m4/getcwd-path-max.m4 b/m4/getcwd-path-max.m4
new file mode 100644
index 0000000..4630a59
--- /dev/null
+++ b/m4/getcwd-path-max.m4
@@ -0,0 +1,217 @@
+# serial 19
+# 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, 2009-2015 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
+
+/* Don't get link errors because mkdir is redefined to rpl_mkdir.  */
+#undef mkdir
+
+#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.  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)))
+            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 $? in
+     10|11|12) gl_cv_func_getcwd_path_max='no, but it is partly working';;
+     31) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
+     32) gl_cv_func_getcwd_path_max='yes, but with shorter paths';;
+     *) gl_cv_func_getcwd_path_max=no;;
+     esac],
+    [case "$host_os" in
+       aix*) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
+       *) gl_cv_func_getcwd_path_max=no;;
+     esac])
+  ])
+])