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authorMattias Andrée <maandree@operamail.com>2014-11-29 17:46:59 +0100
committerMattias Andrée <maandree@operamail.com>2014-11-29 17:46:59 +0100
commit2aca148cbd6db5fa56e1c9a2b63c05845b34225c (patch)
tree784b2ddf774c2c8eb3bc8812c4d4e4a8c00560bf /src/krandom.c
parentadd copying and license (diff)
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code...
Signed-off-by: Mattias Andrée <maandree@operamail.com>
Diffstat (limited to 'src/krandom.c')
-rw-r--r--src/krandom.c214
1 files changed, 214 insertions, 0 deletions
diff --git a/src/krandom.c 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;
+}
+