[git commit] seedrng: code-golf even smaller
Bernhard Reutner-Fischer
rep.dot.nop at gmail.com
Sun Apr 24 08:01:07 UTC 2022
commit: https://git.busybox.net/busybox/commit/?id=f9ea8ba5ed6d43b8b233eac433521eb158e359d1
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
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 at zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop at gmail.com>
---
util-linux/seedrng.c | 42 ++++++++++++++----------------------------
1 file changed, 14 insertions(+), 28 deletions(-)
diff --git a/util-linux/seedrng.c b/util-linux/seedrng.c
index 5a41addf0..374e7f676 100644
--- a/util-linux/seedrng.c
+++ b/util-linux/seedrng.c
@@ -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, ×tamp);
sha256_hash(&hash, ×tamp, 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;
}
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