Add API gpgme_op_random_value.

* src/genrandom.c (getrandom_size_t): New.
(gpgme_op_random_value): New.
* src/gpgme.def: Add new function.
* src/libgpgme.vers: Ditto.
* src/gpgme.h.in: Add prototype.

* tests/run-genrandom.c: Add an option to use the new function.
--

The implementation is not optimized but sufficient for our use case.
Possible improvements for this and gpgme_op_random_bytes are a cache
for random bytes in the context so that we do not need to get out to
gpgme for just a few random bytes.

GnuPG-bug-id: 6694

1 files changed, 68 insertions, 15 deletions

diff --git a/tests/run-genrandom.c b/tests/run-genrandom.c
index 18b8c7ab..f28ef299 100644
--- a/tests/run-genrandom.c
+++ b/tests/run-genrandom.c
@@ -28,6 +28,8 @@
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>
+#include <errno.h>
+#include <stdint.h>
 
 #include <gpgme.h>
 
@@ -42,10 +44,13 @@ static int verbose;
 static int
 show_usage (int ex)
 {
-  fputs ("usage: " PGM " [options]\n\n"
+  fputs ("usage: " PGM " [options] [LIMIT]\n\n"
          "Options:\n"
          "  --verbose        run in verbose mode\n"
          "  --zbase32        generate 30 zbase32 characters\n"
+         "  --hex            return a hex value in LIMIT mode\n"
+         "\n"
+         "With LIMIT return a decimal value in the range [0,LIMIT)\n"
          , stderr);
   exit (ex);
 }
@@ -60,6 +65,8 @@ main (int argc, char **argv)
   gpgme_protocol_t protocol = GPGME_PROTOCOL_OPENPGP;
   gpgme_random_mode_t mode = 0;
   char buffer[128];
+  int hexmode = 0;
+  int valuemode = 0;
 
 
   if (argc)
@@ -85,11 +92,21 @@ main (int argc, char **argv)
           mode = GPGME_RANDOM_MODE_ZBASE32;
           argc--; argv++;
         }
+      else if (!strcmp (*argv, "--hex"))
+        {
+          hexmode = 1;
+          argc--; argv++;
+        }
       else if (!strncmp (*argv, "--", 2))
         show_usage (1);
     }
 
-  if (argc)
+  if (argc == 1)
+    valuemode = 1;
+  else if (argc)
+    show_usage (1);
+
+  if ((valuemode && mode) || (!valuemode && hexmode))
     show_usage (1);
 
   init_gpgme (protocol);
@@ -98,26 +115,62 @@ main (int argc, char **argv)
   fail_if_err (err);
   gpgme_set_protocol (ctx, protocol);
 
-  err = gpgme_op_random_bytes (ctx, mode, buffer, sizeof buffer);
-  if (err)
+  if (valuemode)
     {
-      fprintf (stderr, PGM ": error getting random: %s\n", gpg_strerror (err));
-      exit (1);
-    }
+      size_t limit, value;
+
+      errno = 0;
+      limit = strtoul (*argv, NULL, 0);
+      if (errno)
+        {
+          fprintf (stderr, PGM ": error parsing LIMIT arg: %s\n",
+                   strerror (errno));
+          exit (1);
+        }
+      if (limit > SIZE_MAX)
+        {
+          fprintf (stderr, PGM ": error parsing LIMIT arg: %s\n",
+                   "too large for size_t");
+          exit (1);
+        }
 
-  if (mode == GPGME_RANDOM_MODE_ZBASE32)
-    puts (buffer);
+      err = gpgme_op_random_value (ctx, limit, &value);
+      if (err)
+        {
+          fprintf (stderr, PGM ": error getting random: %s\n",
+                   gpg_strerror (err));
+          exit (1);
+        }
+
+      if (hexmode)
+        printf ("%zx\n", value);
+      else
+        printf ("%zu\n", value);
+    }
   else
     {
-      int i;
+      err = gpgme_op_random_bytes (ctx, mode, buffer, sizeof buffer);
+      if (err)
+        {
+          fprintf (stderr, PGM ": error getting random: %s\n",
+                   gpg_strerror (err));
+          exit (1);
+        }
 
-      for (i=0; i < sizeof buffer; i++)
+      if (mode == GPGME_RANDOM_MODE_ZBASE32)
+        puts (buffer);
+      else
         {
-          if (i && !(i%32))
-            putchar ('\n');
-          printf ("%02x", ((unsigned char *)buffer)[i]);
+          int i;
+
+          for (i=0; i < sizeof buffer; i++)
+            {
+              if (i && !(i%32))
+                putchar ('\n');
+              printf ("%02x", ((unsigned char *)buffer)[i]);
+            }
+          putchar ('\n');
         }
-      putchar ('\n');
     }
 
   gpgme_release (ctx);