rename

1 files changed, 124 insertions, 0 deletions

diff --git a/m4/getcwd-path-max.m4 b/m4/getcwd-path-max.m4
new file mode 100644
index 000000000..e91fa64f5
--- /dev/null
+++ b/m4/getcwd-path-max.m4
@@ -0,0 +1,124 @@
+#serial 1
+# Check whether getcwd has the bug that it succeeds for a working directory
+# longer than PATH_MAX, yet returns a truncated directory name.
+# 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.  */
+
+# From Jim Meyering
+
+AC_DEFUN([GL_FUNC_GETCWD_PATH_MAX],
+[
+  AC_CACHE_CHECK([whether getcwd properly handles paths longer than PATH_MAX],
+                 utils_cv_func_getcwd_vs_path_max,
+  [
+  # Arrange for deletion of the temporary directory this test creates.
+  ac_clean_files="$ac_clean_files confdir3"
+  AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#ifndef CHAR_BIT
+# define CHAR_BIT 8
+#endif
+
+/* The extra casts work around common compiler bugs.  */
+#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
+/* The outer cast is needed to work around a bug in Cray C 5.0.3.0.
+   It is necessary at least when t == time_t.  */
+#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
+			      ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
+#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
+
+#ifndef INT_MAX
+# define INT_MAX TYPE_MAXIMUM (int)
+#endif
+
+#ifndef PATH_MAX
+/* There might be a better way to handle this case, but note:
+   - the value shouldn't be anywhere near INT_MAX, and
+   - the value shouldn't be so big that the local declaration, below,
+   blows the stack.  */
+# define PATH_MAX 40000
+#endif
+
+/* The length of this name must be 8.  */
+#define DIR_NAME "confdir3"
+
+int
+main ()
+{
+  /* The '9' comes from strlen (DIR_NAME) + 1.  */
+#if INT_MAX - 9 <= PATH_MAX
+  /* FIXME: Assuming there's a system for which this is true -- Hurd?,
+     this should be done in a compile test.  */
+  exit (0);
+#else
+  char buf[PATH_MAX + 20];
+  char *cwd = getcwd (buf, PATH_MAX);
+  size_t cwd_len;
+  int fail = 0;
+  size_t n_chdirs = 0;
+
+  if (cwd == NULL)
+    exit (1);
+
+  cwd_len = strlen (cwd);
+
+  while (1)
+    {
+      char *c;
+      size_t len;
+
+      cwd_len += 1 + strlen (DIR_NAME);
+      /* If mkdir or chdir fails, be pessimistic and consider that
+	 as a failure, too.  */
+      if (mkdir (DIR_NAME, 0700) < 0
+	  || chdir (DIR_NAME) < 0
+	  || ((c = getcwd (buf, PATH_MAX)) != NULL
+	      && (len = strlen (c)) != cwd_len))
+	{
+	  fail = 1;
+	  break;
+	}
+      ++n_chdirs;
+      if (PATH_MAX < len)
+	break;
+    }
+
+  /* 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;
+
+    /* Unlink first, in case the chdir failed.  */
+    unlink (DIR_NAME);
+    for (i = 0; i <= n_chdirs; i++)
+      {
+	if (chdir ("..") < 0)
+	  break;
+	rmdir (DIR_NAME);
+      }
+  }
+
+  exit (fail);
+#endif
+}
+  ]])],
+       [utils_cv_func_getcwd_vs_path_max=yes],
+       [utils_cv_func_getcwd_vs_path_max=no],
+       [utils_cv_func_getcwd_vs_path_max=no])])
+
+  if test $utils_cv_func_getcwd_vs_path_max = yes; then
+    AC_LIBOBJ(getcwd)
+    AC_DEFINE(getcwd, rpl_getcwd,
+      [Define to rpl_getcwd if the wrapper function should be used.])
+  fi
+])