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seedrng: code-golf even smaller

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Since we're passing 0 as the timeout, we don't need safe_poll. Remove
cleanup at end of program, since OS does that, which lets us simplify
control flow. Factor repeated function calls into ternary loop.

function                                             old     new   delta
seedrng_main                                        1061    1459    +398
seed_from_file_if_exists                             468       -    -468
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/0 up/down: 398/-468)          Total: -70 bytes
   text    data     bss     dec     hex filename
1052781   16515    1816 1071112  105808 busybox_old
1052711   16515    1816 1071042  1057c2 busybox_unstripped

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
This commit is contained in:
Jason A. Donenfeld 2022-04-21 12:37:32 +02:00 committed by Bernhard Reutner-Fischer
parent 831c754c91
commit f9ea8ba5ed
1 changed files with 14 additions and 28 deletions
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42
util-linux/seedrng.c
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@ -102,7 +102,7 @@ static int read_new_seed(uint8_t *seed, size_t len, bool *is_creditable)
};
if (random_fd.fd < 0)
return -1;
*is_creditable = safe_poll(&random_fd, 1, 0) == 1;
*is_creditable = poll(&random_fd, 1, 0) == 1;
close(random_fd.fd);
} else if (getrandom(seed, len, GRND_INSECURE) == (ssize_t)len)
return 0;
@ -174,15 +174,13 @@ int seedrng_main(int argc, char *argv[]) MAIN_EXTERNALLY_VISIBLE;
int seedrng_main(int argc UNUSED_PARAM, char *argv[])
{
const char *seed_dir = DEFAULT_SEED_DIR, *creditable_seed, *non_creditable_seed;
int ret, fd = -1, dfd = -1, program_ret = 0;
int fd, dfd, program_ret = 0;
uint8_t new_seed[MAX_SEED_LEN];
size_t new_seed_len;
bool new_seed_creditable;
bool skip_credit = false;
bool new_seed_creditable, skip_credit = false;
struct timespec timestamp = { 0 };
sha256_ctx_t hash;
int opt;
enum {
OPT_d = (1 << 0),
OPT_n = (1 << 1)
@ -194,8 +192,7 @@ int seedrng_main(int argc UNUSED_PARAM, char *argv[])
;
#endif
opt = getopt32long(argv, "d:n", longopts, &seed_dir);
skip_credit = opt & OPT_n;
skip_credit = getopt32long(argv, "d:n", longopts, &seed_dir) & OPT_n;
creditable_seed = concat_path_file(seed_dir, CREDITABLE_SEED_NAME);
non_creditable_seed = concat_path_file(seed_dir, NON_CREDITABLE_SEED_NAME);
@ -207,11 +204,8 @@ int seedrng_main(int argc UNUSED_PARAM, char *argv[])
bb_perror_msg_and_die("unable to %s seed directory", "create");
dfd = open(seed_dir, O_DIRECTORY | O_RDONLY);
if (dfd < 0 || flock(dfd, LOCK_EX) < 0) {
bb_perror_msg("unable to %s seed directory", "lock");
program_ret = 1;
goto out;
}
if (dfd < 0 || flock(dfd, LOCK_EX) < 0)
bb_perror_msg_and_die("unable to %s seed directory", "lock");
sha256_begin(&hash);
sha256_hash(&hash, "SeedRNG v1 Old+New Prefix", 25);
@ -220,16 +214,14 @@ int seedrng_main(int argc UNUSED_PARAM, char *argv[])
clock_gettime(CLOCK_BOOTTIME, &timestamp);
sha256_hash(&hash, &timestamp, sizeof(timestamp));
ret = seed_from_file_if_exists(non_creditable_seed, dfd, false, &hash);
if (ret < 0)
program_ret |= 1 << 1;
ret = seed_from_file_if_exists(creditable_seed, dfd, !skip_credit, &hash);
if (ret < 0)
program_ret |= 1 << 2;
for (int i = 1; i < 3; ++i) {
if (seed_from_file_if_exists(i == 1 ? non_creditable_seed : creditable_seed,
dfd, i == 1 ? false : !skip_credit, &hash) < 0)
program_ret |= 1 << i;
}
new_seed_len = determine_optimal_seed_len();
ret = read_new_seed(new_seed, new_seed_len, &new_seed_creditable);
if (ret < 0) {
if (read_new_seed(new_seed, new_seed_len, &new_seed_creditable) < 0) {
bb_perror_msg("unable to%s seed", " read new");
new_seed_len = SHA256_OUTSIZE;
memset(new_seed, 0, SHA256_OUTSIZE);
@ -243,17 +235,11 @@ int seedrng_main(int argc UNUSED_PARAM, char *argv[])
fd = open(non_creditable_seed, O_WRONLY | O_CREAT | O_TRUNC, 0400);
if (fd < 0 || full_write(fd, new_seed, new_seed_len) != (ssize_t)new_seed_len || fsync(fd) < 0) {
bb_perror_msg("unable to%s seed", " write");
program_ret |= 1 << 4;
goto out;
return program_ret | (1 << 4);
}
if (new_seed_creditable && rename(non_creditable_seed, creditable_seed) < 0) {
bb_simple_perror_msg("unable to make new seed creditable");
program_ret |= 1 << 5;
return program_ret | (1 << 5);
}
out:
if (ENABLE_FEATURE_CLEAN_UP && fd >= 0)
close(fd);
if (ENABLE_FEATURE_CLEAN_UP && dfd >= 0)
close(dfd);
return program_ret;
}