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authorJim Meyering <jim@meyering.net>2003-03-04 17:18:13 +0000
committerJim Meyering <jim@meyering.net>2003-03-04 17:18:13 +0000
commit618481ca0cf615697373edea7da1c17cd67f01cc (patch)
tree14d48180e1a9b3d28084baed0c9a9294428a56d8 /m4
parent59ae46343b1fb621b47af2496deb132ab9458585 (diff)
downloadcoreutils-618481ca0cf615697373edea7da1c17cd67f01cc.tar.xz
*** empty log message ***
Diffstat (limited to 'm4')
-rw-r--r--m4/getcwd-robust.m4112
1 files changed, 112 insertions, 0 deletions
diff --git a/m4/getcwd-robust.m4 b/m4/getcwd-robust.m4
new file mode 100644
index 000000000..3e5f49d5f
--- /dev/null
+++ b/m4/getcwd-robust.m4
@@ -0,0 +1,112 @@
+#serial 1
+# Check whether getcwd can return a path longer than PATH_MAX.
+# If not, arrange to compile the wrapper function.
+# From Jim Meyering
+
+AC_DEFUN([GL_FUNC_GETCWD_ROBUST],
+[
+ AC_CACHE_CHECK([whether getcwd can return a path longer than PATH_MAX],
+ utils_cv_func_getcwd_robust,
+ [
+ # 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
+# 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 (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_robust=yes],
+ [utils_cv_func_getcwd_robust=no],
+ [utils_cv_func_getcwd_robust=no])])
+
+ if test $utils_cv_func_getcwd_robust = yes; then
+ AC_LIBOBJ(getcwd)
+ AC_DEFINE(getcwd, rpl_getcwd,
+ [Define to rpl_getcwd if the wrapper function should be used.])
+ fi
+])