1 files changed, 145 insertions, 0 deletions
diff --git a/common/sexputil.c b/common/sexputil.c
new file mode 100644
index 000000000..fe0870c56
--- /dev/null
+++ b/common/sexputil.c
@@ -0,0 +1,145 @@
+/* sexputil.c - Utility fnctions for S-expressions.
+ * Copyright (C) 2005 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+ * USA.
+ */
+
+/* This file implements a few utility functions useful when working
+   with canonical encrypted S-expresions (i.e. not the S-exprssion
+   objects from libgcrypt).  */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#ifdef HAVE_LOCALE_H
+#include <locale.h>
+#endif
+
+#include "util.h"
+
+
+/* Return the so called "keygrip" which is the SHA-1 hash of the
+   public key parameters expressed in a way depended on the algorithm.
+
+   KEY is expected to be an canonical encoded S-expression with a
+   public or private key. KEYLEN is the length of that buffer.
+
+   GRIP must be at least 20 bytes long On success 0 is return, on
+   error an aerror code. */
+gpg_error_t
+keygrip_from_canon_sexp (const unsigned char *key, size_t keylen,
+                         unsigned char *grip)
+{
+  gpg_error_t err;
+  gcry_sexp_t sexp;
+
+  if (!grip)
+    return gpg_error (GPG_ERR_INV_VALUE);
+  err = gcry_sexp_sscan (&sexp, NULL, (const char *)key, keylen);
+  if (err)
+    return err;
+  if (!gcry_pk_get_keygrip (sexp, grip))
+    err = gpg_error (GPG_ERR_INTERNAL);
+  gcry_sexp_release (sexp);
+  return err;
+}
+
+
+/* Compare two simple S-expressions like "(3:foo)".  Returns 0 if they
+   are identical or !0 if they are not.  Not that this function can't
+   be used for sorting. */
+int
+cmp_simple_canon_sexp (const unsigned char *a_orig,
+                       const unsigned char *b_orig)
+{
+  const char *a = (const char *)a_orig;
+  const char *b = (const char *)b_orig;
+  unsigned long n1, n2;
+  char *endp;
+
+  if (!a && !b)
+    return 0; /* Both are NULL, they are identical. */
+  if (!a || !b)
+    return 1; /* One is NULL, they are not identical. */
+  if (*a != '(' || *b != '(')
+    log_bug ("invalid S-exp in cmp_simple_canon_sexp\n");
+
+  a++;
+  n1 = strtoul (a, &endp, 10);
+  a = endp;
+  b++;
+  n2 = strtoul (b, &endp, 10);
+  b = endp;
+
+  if (*a != ':' || *b != ':' )
+    log_bug ("invalid S-exp in cmp_simple_canon_sexp\n");
+  if (n1 != n2)
+    return 1; /* Not the same. */
+
+  for (a++, b++; n1; n1--, a++, b++)
+    if (*a != *b)
+      return 1; /* Not the same. */
+  return 0;
+}
+
+
+/* Create a simple S-expression from the hex string at LIBNE.  Returns
+   a newly allocated buffer with that canonical encoded S-expression
+   or NULL in case of an error.  On return the number of characters
+   scanned in LINE will be stored at NSCANNED.  This fucntions stops
+   converting at the first character not representing a hexdigit. Odd
+   numbers of hex digits are allowed; a leading zero is then
+   assumed. If no characters have been found, NULL is returned.*/
+unsigned char *
+make_simple_sexp_from_hexstr (const char *line, size_t *nscanned)
+{
+  size_t n, len;
+  const char *s;
+  unsigned char *buf;
+  unsigned char *p;
+  char numbuf[50];
+
+  for (n=0, s=line; hexdigitp (s); s++, n++)
+    ;
+  if (nscanned)
+    *nscanned = n;
+  if (!n)
+    return NULL;
+  len = ((n+1) & ~0x01)/2; 
+  sprintf (numbuf, "(%u:", (unsigned int)len);
+  buf = xtrymalloc (strlen (numbuf) + len + 1 + 1);
+  if (!buf)
+    return NULL;
+  p = (unsigned char *)stpcpy ((char *)buf, numbuf);
+  s = line;
+  if ((n&1))
+    {
+      *p++ = xtoi_1 (s);
+      s++;
+      n--;
+    }
+  for (; n > 1; n -=2, s += 2)
+    *p++ = xtoi_2 (s);
+  *p++ = ')';
+  *p = 0; /* (Not really neaded.) */
+
+  return buf;
+}