Implement scandirat function

1 files changed, 143 insertions, 0 deletions

diff --git a/dirent/scandirat.c b/dirent/scandirat.c
new file mode 100644
index 0000000..e6f5ece
--- /dev/null
+++ b/dirent/scandirat.c
@@ -0,0 +1,143 @@
+/* Copyright (C) 1992-1998,2000,2002,2003,2009,2011
+   Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <dirent.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <bits/libc-lock.h>
+
+#ifndef SCANDIRAT
+# define SCANDIRAT scandirat
+# define READDIR __readdir
+# define DIRENT_TYPE struct dirent
+#endif
+
+#ifndef SKIP_SCANDIR_CANCEL
+void
+__scandir_cancel_handler (void *arg)
+{
+  struct scandir_cancel_struct *cp = arg;
+  size_t i;
+  void **v = cp->v;
+
+  for (i = 0; i < cp->cnt; ++i)
+    free (v[i]);
+  free (v);
+  (void) __closedir (cp->dp);
+}
+#endif
+
+
+int
+SCANDIRAT (dfd, dir, namelist, select, cmp)
+     int dfd;
+     const char *dir;
+     DIRENT_TYPE ***namelist;
+     int (*select) (const DIRENT_TYPE *);
+     int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **);
+{
+  DIR *dp = __opendirat (dfd, dir);
+  DIRENT_TYPE **v = NULL;
+  size_t vsize = 0;
+  struct scandir_cancel_struct c;
+  DIRENT_TYPE *d;
+  int save;
+
+  if (dp == NULL)
+    return -1;
+
+  save = errno;
+  __set_errno (0);
+
+  c.dp = dp;
+  c.v = NULL;
+  c.cnt = 0;
+  __libc_cleanup_push (__scandir_cancel_handler, &c);
+
+  while ((d = READDIR (dp)) != NULL)
+    {
+      int use_it = select == NULL;
+
+      if (! use_it)
+	{
+	  use_it = select (d);
+	  /* The select function might have changed errno.  It was
+	     zero before and it need to be again to make the latter
+	     tests work.  */
+	  __set_errno (0);
+	}
+
+      if (use_it)
+	{
+	  DIRENT_TYPE *vnew;
+	  size_t dsize;
+
+	  /* Ignore errors from select or readdir */
+	  __set_errno (0);
+
+	  if (__builtin_expect (c.cnt == vsize, 0))
+	    {
+	      DIRENT_TYPE **new;
+	      if (vsize == 0)
+		vsize = 10;
+	      else
+		vsize *= 2;
+	      new = (DIRENT_TYPE **) realloc (v, vsize * sizeof (*v));
+	      if (new == NULL)
+		break;
+	      v = new;
+	      c.v = (void *) v;
+	    }
+
+	  dsize = &d->d_name[_D_ALLOC_NAMLEN (d)] - (char *) d;
+	  vnew = (DIRENT_TYPE *) malloc (dsize);
+	  if (vnew == NULL)
+	    break;
+
+	  v[c.cnt++] = (DIRENT_TYPE *) memcpy (vnew, d, dsize);
+	}
+    }
+
+  if (__builtin_expect (errno, 0) != 0)
+    {
+      save = errno;
+
+      while (c.cnt > 0)
+	free (v[--c.cnt]);
+      free (v);
+      c.cnt = -1;
+    }
+  else
+    {
+      /* Sort the list if we have a comparison function to sort with.  */
+      if (cmp != NULL)
+	qsort (v, c.cnt, sizeof (*v),
+	       (int (*) (const void *, const void *)) cmp);
+
+      *namelist = v;
+    }
+
+  __libc_cleanup_pop (0);
+
+  (void) __closedir (dp);
+  __set_errno (save);
+
+  return c.cnt;
+}