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#include "randgen.h"
#include "htable.h"
#include <assert.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
/*
Generates a random id of length `size-1` consisting of characters in the set
[1-6] and places it in the buffer pointed to by `id`. The buffer is NULL
terminated.
*/
int get_random_id(struct randgen *randgen, char *id, size_t size)
{
assert(randgen != NULL);
assert(id != NULL);
assert(size > 0);
if (randgen_generate(randgen, id, size-1) == -1)
return -1;
id[--size] = '\0';
while (size > 0)
{
unsigned char q = ((unsigned char *) id)[size-1];
id[--size] = '1' + (q % 6);
}
return 0;
}
/*
Makes a copy of the supplied string. If `len` is < 0, strlen() is used to
calculate the string length. The resulting string is always NULL terminated.
*/
char *my_strdup(const char *s, int len)
{
char *result;
assert(s != NULL);
if (len < 0)
len = strlen(s);
result = (char *) malloc(sizeof(char) * (len+1));
memcpy(result, s, len);
result[len] = '\0';
return result;
}
/*
Parse a line from a diceware dictionary file. An acceptable line is of the
form:
11111 aaabbbccc
where 11111 is the word id in decimal digits and aaabbbccc is a word
stopping at first whitespace.
Returns a pointer to a htable_entry on success, NULL otherwise. Calls
exit() if memory could not be allocated.
*/
struct htable_entry *parse_line(const char *line)
{
struct htable_entry *entry;
char id[32];
char word[256];
assert(line != NULL);
if (sscanf(line, "%31[1-6] %255s", id, word) != 2)
{
return NULL;
}
entry = (struct htable_entry *) malloc(sizeof(*entry));
if (!entry)
{
fprintf(stderr, "%s\n", strerror(errno));
exit(EXIT_FAILURE);
}
entry->id = my_strdup(id, -1);
entry->word = my_strdup(word, -1);
return entry;
}
/*
Loads a diceware dictionary file. Returns 0 on success and -1 on error.
*/
int load_dictionary(const char *filename, struct htable *dict)
{
FILE *fp;
int rc = -1;
struct htable_entry *entry;
char line[256];
if ((fp = fopen(filename, "r")) == NULL)
{
fprintf(stderr, "could not open %s: %s\n", filename, strerror(errno));
goto cleanup;
}
while (1)
{
if (!fgets(line, sizeof(line), fp))
break;
/* Skip invalid lines. */
if ((entry = parse_line(line)) == NULL)
continue;
htable_put(dict, entry);
}
rc = 0;
cleanup:
if (fp)
fclose(fp);
return rc;
}
/*
Returns a random word from a dictionary.
*/
char *get_random_word(struct randgen *randgen, struct htable *dict)
{
struct htable_entry *entry;
char id[6];
assert(randgen != NULL);
assert(dict != NULL);
if (get_random_id(randgen, id, sizeof(id)) == -1)
{
fprintf(stderr, "%s\n", "get_random_id failed");
return NULL;
}
entry = htable_get(dict, id);
if (!entry)
{
fprintf(stderr, "no such word: %s\n", id);
return NULL;
}
return entry->word;
}
void usage(const char *prog)
{
static const char *usagestr =
"%s [-d DICTIONARY] [-n COUNT]"
#ifndef _WIN32
" [-r DEVICE]"
#endif
"\n\n"
"\t-d use DICTIONARY as the dictionary file\n"
"\t-n output COUNT words\n"
#ifndef _WIN32
"\t-r read random bytes from DEVICE\n"
#endif
"\n";
fprintf(stderr, usagestr, prog);
exit(EXIT_FAILURE);
}
int main(int argc, char **argv)
{
const char *dictfilename = "diceware.txt";
const char *randomdevice = NULL;
int words = 6;
int i = 0;
struct htable dict;
struct randgen *randgen = NULL;
int rc = 0;
memset(&dict, 0, sizeof(dict));
for (i = 1; i < argc; ++i)
{
if (!strcmp(argv[i], "-d") && i+1 < argc)
{
dictfilename = argv[++i];
}
else if (!strcmp(argv[i], "-n") && i+1 < argc)
{
words = atoi(argv[++i]);
}
#ifndef _WIN32
else if (!strcmp(argv[i], "-r") && i+1 < argc)
{
randomdevice = argv[++i];
}
#endif
else if (!strcmp(argv[i], "-h"))
{
usage(argv[0]);
}
else
{
usage(argv[0]);
}
}
if ((randgen = randgen_open(randomdevice)) == NULL)
goto error;
htable_init(&dict, 11000);
if (load_dictionary(dictfilename, &dict) == -1)
goto error;
for (i = 0; i < words; ++i)
{
char *word = get_random_word(randgen, &dict);
if (!word)
{
goto error;
}
printf("%s%s", i ? " " : "", word);
}
printf("\n");
goto finally;
error:
rc = 1;
finally:
randgen_close(randgen);
htable_deinit(&dict);
return rc;
}
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