bugs in realpath

[Eric Blake <ebb9 at byu dot net>]

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By my reading of POSIX, realpath() has several bugs.
 realpath("//", buf) should output "//", but currently resolves to
/cygdrive/c/
 realpath("nonexistent", buf) should fail with ENOENT, but currently
resolves to `pwd`/nonexistent
 realpath(NULL, buf) should fail with EINVAL, but currently fails with EFAULT
 realpath("linktofile/x", buf) should fail with ENOTDIR, but currently
resolves to `pwd`/file/x
 realpath("c:..", buf) should resolve to "/cygdrive" (or whatever
cygdrive-prefix is, of course), but currently resolves to "/cygdrive/c"
 realpath("c:/..", buf) should resolve to "/cygdrive", but for me resolved
to a bogus "/tmp/ca"

(Plus the issue that .. is resolved incorrectly on symlinks, but fixing
that is a much bigger task and affects more than realpath)

I tested these using:
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <limits.h>
#include <stdio.h>

int
main (int argc, char* argv[])
{
  char resolved[PATH_MAX];
  int i;
  if (argc == 1)
    argc = 2;
  for (i = 1; i < argc; i++)
    {
      char *res;
      errno = 0;
      res = realpath(argv[i], resolved);
      printf("'%s': %s (%s), %d %s\n", argv[i] ? argv[i] : "NULL",
             res ? res : "NULL", res == resolved ? "same" : resolved,
             errno, strerror(errno));
    }
  return 0;
}


- --
Life is short - so eat dessert first!

Eric Blake             ebb9@byu.net
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