code...

Signed-off-by: Mattias Andrée <maandree@operamail.com>

2 files changed, 216 insertions, 0 deletions

diff --git a/README b/README
new file mode 100644
index 0000000..5dbe2f4
--- /dev/null
+++ b/README
@@ -0,0 +1,2 @@
+Keccak-based userspace pseudorandom number generator.
+
diff --git a/src/krandom.c b/src/krandom.c
new file mode 100644
index 0000000..b049bc8
--- /dev/null
+++ b/src/krandom.c
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+/**
+ * featherweight – Keccak-based userspace pseudorandom number generator
+ * Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <alloca.h>
+
+#include <libkeccak.h>
+#include <argparser.h>
+
+
+
+#ifndef URANDOM
+# ifndef DEVDIR
+#  define DEVDIR  "/dev"
+# endif
+# define URANDOM  DEVDIR "/urandom"
+#endif
+
+
+
+#define USER_ERROR(string) 				\
+  (fprintf(stderr, "%s: %s.\n", execname, string), 1)
+
+#define ADD(arg, desc, ...)								\
+  (arg ? args_add_option(args_new_argumented(NULL, arg, 0, __VA_ARGS__, NULL), desc)	\
+       : args_add_option(args_new_argumentless(NULL, 0, __VA_ARGS__, NULL), desc))
+
+#define LAST(arg)					\
+  (args_opts_get(arg)[args_opts_get_count(arg) - 1])
+
+
+
+/**
+ * `argv[0]` from `main`
+ */
+static char* execname;
+
+
+/**
+ * Convert `libkeccak_generalised_spec_t` to `libkeccak_spec_t` and check for errors
+ * 
+ * @param   gspec  See `libkeccak_degeneralise_spec` 
+ * @param   spec   See `libkeccak_degeneralise_spec` 
+ * @return         Zero on success, an appropriate exit value on error
+ */
+static int make_spec(libkeccak_generalised_spec_t* restrict gspec, libkeccak_spec_t* restrict spec)
+{
+  int r;
+  
+#define TEST(CASE, STR)  case LIBKECCAK_GENERALISED_SPEC_ERROR_##CASE:  return USER_ERROR(STR)
+  if (r = libkeccak_degeneralise_spec(gspec, spec), r)
+    switch (r)
+      {
+	TEST (STATE_NONPOSITIVE,      "the state size must be positive");
+	TEST (STATE_TOO_LARGE,        "the state size is too large, may not exceed 1600");
+	TEST (STATE_MOD_25,           "the state size must be a multiple of 25");
+	TEST (WORD_NONPOSITIVE,       "the word size must be positive");
+	TEST (WORD_TOO_LARGE,         "the word size is too large, may not exceed 64");
+	TEST (STATE_WORD_INCOHERENCY, "the state size must be exactly 25 times the word size");
+	TEST (CAPACITY_NONPOSITIVE,   "the capacity must be positive");
+	TEST (CAPACITY_MOD_8,         "the capacity must be a multiple of 8");
+	TEST (BITRATE_NONPOSITIVE,    "the rate must be positive");
+	TEST (BITRATE_MOD_8,          "the rate must be a multiple of 8");
+	TEST (OUTPUT_NONPOSITIVE,     "the output size must be positive");
+      default:
+	return USER_ERROR("unknown error in algorithm parameters");
+    }
+#undef TEST
+  
+#define TEST(CASE, STR)  case LIBKECCAK_SPEC_ERROR_##CASE:  return USER_ERROR(STR)
+  if (r = libkeccak_spec_check(spec), r)
+    switch (r)
+      {
+      TEST (BITRATE_NONPOSITIVE,  "the rate size must be positive");
+      TEST (BITRATE_MOD_8,        "the rate must be a multiple of 8");
+      TEST (CAPACITY_NONPOSITIVE, "the capacity must be positive");
+      TEST (CAPACITY_MOD_8,       "the capacity must be a multiple of 8");
+      TEST (OUTPUT_NONPOSITIVE,   "the output size must be positive");
+      TEST (STATE_TOO_LARGE,      "the state size is too large, may not exceed 1600");
+      TEST (STATE_MOD_25,         "the state size must be a multiple of 25");
+      TEST (WORD_NON_2_POTENT,    "the word size must be a power of 2");
+      TEST (WORD_MOD_8,           "the word size must be a multiple of 8");
+      default:
+	return USER_ERROR("unknown error in algorithm parameters");
+      }
+#undef TEST
+  
+  return 0;
+}
+
+
+
+/**
+ * Mane!
+ * 
+ * @param   argc  The number of elements in `argv`
+ * @param   argv  Command line arguments
+ * @return        Zero on and only on success
+ */
+int main(int argc, char** argv)
+{
+  char* restrict generated_random = NULL;
+  libkeccak_generalised_spec_t gspec;
+  libkeccak_spec_t spec;
+  libkeccak_state_t state;
+  size_t length, ptr;
+  ssize_t got;
+  int r, fd = -1, verbose = 0;
+  
+  execname = *argv;
+  
+  
+  memset(&state, 0, sizeof(libkeccak_state_t));
+  libkeccak_generalised_spec_initialise(&gspec);
+  
+  args_init("Keccak-based userspace pseudorandom number generator",
+	    "krandom [options...]", NULL,
+	    NULL, 1, 0, args_standard_abbreviations);
+   
+  ADD(NULL,       "Display option summary", "-h", "--help");
+  ADD("RATE",     "Select rate",            "-R", "--bitrate", "--rate");
+  ADD("CAPACITY", "Select capacity",        "-C", "--capacity");
+  ADD("SIZE",     "Select output size",     "-N", "-O", "--output-size", "--output");
+  ADD("SIZE",     "Select state size",      "-S", "-B", "--state-size", "--state");
+  ADD("SIZE",     "Select word size",       "-W", "--word-size", "--word");
+  ADD(NULL,       "Be verbose",             "-v", "--verbose");
+  
+  args_parse(argc, argv);
+  
+  if (args_opts_used("-h"))  return args_help(0), args_dispose(), 0;
+  if (args_opts_used("-R"))  gspec.bitrate    = atol(LAST("-R"));
+  if (args_opts_used("-C"))  gspec.capacity   = atol(LAST("-C"));
+  if (args_opts_used("-N"))  gspec.output     = atol(LAST("-N"));
+  if (args_opts_used("-S"))  gspec.state_size = atol(LAST("-S"));
+  if (args_opts_used("-W"))  gspec.word_size  = atol(LAST("-W"));
+  if (args_opts_used("-v"))  verbose          = 1;
+  
+  if ((r = make_spec(&gspec, &spec)))
+      goto done;
+  
+  if (verbose)
+    {
+      fprintf(stderr, "%s: "        "rate: %li\n", execname, gspec.bitrate);
+      fprintf(stderr, "%s: "    "capacity: %li\n", execname, gspec.capacity);
+      fprintf(stderr, "%s: " "output size: %li\n", execname, gspec.output);
+      fprintf(stderr, "%s: "  "state size: %li\n", execname, gspec.state_size);
+      fprintf(stderr, "%s: "   "word size: %li\n", execname, gspec.word_size);
+    }
+  
+  libkeccak_state_initialise(&state, &spec);
+  
+  fd = open(URANDOM, O_RDONLY);
+  if (fd < 0)
+    goto fail;
+  for (ptr = 0, length = sizeof(state.S); ptr < length;)
+    {
+      got = read(fd, (char*)(state.S) + ptr, length - ptr);
+      if (got <= 0)
+	goto fail;
+      ptr += (size_t)got;
+    }
+  close(fd), fd = -1;
+  
+  length = (size_t)((spec.output + 7) / 8);
+  generated_random = malloc(length);
+  if (generated_random == NULL)
+    goto fail;
+  
+  for (;;)
+    {
+      libkeccak_squeeze(&state, generated_random);
+      got = write(STDOUT_FILENO, generated_random, length);
+      if (got >= 0)
+	continue;
+      if (errno == EPIPE)
+	break;
+      goto fail;
+    }
+  
+  
+ done:
+  if (fd >= 0)
+    close(fd);
+  args_dispose();
+  free(generated_random);
+  libkeccak_state_fast_destroy(&state);
+  return r;
+ fail:
+  perror(execname);
+  r = 2;
+  goto done;
+}
+