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seedrng: remove some global variables

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- Remove global variables and pass dfd by value, opened once instead of
  twice, which shaves off some more bytes.

function                                             old     new   delta
seedrng_main                                        1086    1088      +2
seed_dir                                               8       -      -8
non_creditable_seed                                    8       -      -8
lock_file                                              8       -      -8
creditable_seed                                        8       -      -8
seed_from_file_if_exists                             456     426     -30
------------------------------------------------------------------------------
(add/remove: 0/4 grow/shrink: 1/1 up/down: 2/-62)             Total: -60 bytes
   text	   data	    bss	    dec	    hex	filename
 976236	   4227	   1848	 982311	  efd27	busybox_old
 976208	   4227	   1816	 982251	  efceb	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 2022-04-20 15:31:01 +02:00 committed by Bernhard Reutner-Fischer
parent 31ec481baf
commit 3c60711f83
1 changed files with 16 additions and 16 deletions
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32
util-linux/seedrng.c
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@ -21,7 +21,7 @@
*/ */
//config:config SEEDRNG //config:config SEEDRNG
//config: bool "seedrng (2.5 kb)" //config: bool "seedrng (2.4 kb)"
//config: default y //config: default y
//config: help //config: help
//config: Seed the kernel RNG from seed files, meant to be called //config: Seed the kernel RNG from seed files, meant to be called
@ -76,8 +76,6 @@
#define CREDITABLE_SEED_NAME "seed.credit" #define CREDITABLE_SEED_NAME "seed.credit"
#define NON_CREDITABLE_SEED_NAME "seed.no-credit" #define NON_CREDITABLE_SEED_NAME "seed.no-credit"
static char *seed_dir, *lock_file, *creditable_seed, *non_creditable_seed;
enum seedrng_lengths { enum seedrng_lengths {
MIN_SEED_LEN = SHA256_OUTSIZE, MIN_SEED_LEN = SHA256_OUTSIZE,
MAX_SEED_LEN = 512 MAX_SEED_LEN = 512
@ -153,18 +151,12 @@ static int seed_rng(uint8_t *seed, size_t len, bool credit)
return ret ? -1 : 0; return ret ? -1 : 0;
} }
static int seed_from_file_if_exists(const char *filename, bool credit, sha256_ctx_t *hash) static int seed_from_file_if_exists(const char *filename, int dfd, bool credit, sha256_ctx_t *hash)
{ {
uint8_t seed[MAX_SEED_LEN]; uint8_t seed[MAX_SEED_LEN];
ssize_t seed_len; ssize_t seed_len;
int dfd = -1, ret = 0; int ret = 0;
dfd = open(seed_dir, O_DIRECTORY | O_RDONLY);
if (dfd < 0) {
ret = -errno;
bb_simple_perror_msg("unable to open seed directory");
goto out;
}
seed_len = open_read_close(filename, seed, sizeof(seed)); seed_len = open_read_close(filename, seed, sizeof(seed));
if (seed_len < 0) { if (seed_len < 0) {
if (errno != ENOENT) { if (errno != ENOENT) {
@ -189,8 +181,6 @@ static int seed_from_file_if_exists(const char *filename, bool credit, sha256_ct
if (ret < 0) if (ret < 0)
bb_simple_perror_msg("unable to seed"); bb_simple_perror_msg("unable to seed");
out: out:
if (ENABLE_FEATURE_CLEAN_UP && dfd >= 0)
close(dfd);
errno = -ret; errno = -ret;
return ret ? -1 : 0; return ret ? -1 : 0;
} }
@ -200,7 +190,8 @@ int seedrng_main(int argc UNUSED_PARAM, char *argv[])
{ {
static const char seedrng_prefix[] = "SeedRNG v1 Old+New Prefix"; static const char seedrng_prefix[] = "SeedRNG v1 Old+New Prefix";
static const char seedrng_failure[] = "SeedRNG v1 No New Seed Failure"; static const char seedrng_failure[] = "SeedRNG v1 No New Seed Failure";
int ret, fd = -1, lock, program_ret = 0; char *seed_dir, *lock_file, *creditable_seed, *non_creditable_seed;
int ret, fd = -1, dfd = -1, lock, program_ret = 0;
uint8_t new_seed[MAX_SEED_LEN]; uint8_t new_seed[MAX_SEED_LEN];
size_t new_seed_len; size_t new_seed_len;
bool new_seed_creditable; bool new_seed_creditable;
@ -245,6 +236,13 @@ int seedrng_main(int argc UNUSED_PARAM, char *argv[])
goto out; goto out;
} }
dfd = open(seed_dir, O_DIRECTORY | O_RDONLY);
if (dfd < 0) {
bb_simple_perror_msg("unable to open seed directory");
program_ret = 1;
goto out;
}
sha256_begin(&hash); sha256_begin(&hash);
sha256_hash(&hash, seedrng_prefix, strlen(seedrng_prefix)); sha256_hash(&hash, seedrng_prefix, strlen(seedrng_prefix));
clock_gettime(CLOCK_REALTIME, &timestamp); clock_gettime(CLOCK_REALTIME, &timestamp);
@ -252,10 +250,10 @@ int seedrng_main(int argc UNUSED_PARAM, char *argv[])
clock_gettime(CLOCK_BOOTTIME, &timestamp); clock_gettime(CLOCK_BOOTTIME, &timestamp);
sha256_hash(&hash, &timestamp, sizeof(timestamp)); sha256_hash(&hash, &timestamp, sizeof(timestamp));
ret = seed_from_file_if_exists(non_creditable_seed, false, &hash); ret = seed_from_file_if_exists(non_creditable_seed, dfd, false, &hash);
if (ret < 0) if (ret < 0)
program_ret |= 1 << 1; program_ret |= 1 << 1;
ret = seed_from_file_if_exists(creditable_seed, !skip_credit, &hash); ret = seed_from_file_if_exists(creditable_seed, dfd, !skip_credit, &hash);
if (ret < 0) if (ret < 0)
program_ret |= 1 << 2; program_ret |= 1 << 2;
@ -290,6 +288,8 @@ int seedrng_main(int argc UNUSED_PARAM, char *argv[])
out: out:
if (ENABLE_FEATURE_CLEAN_UP && fd >= 0) if (ENABLE_FEATURE_CLEAN_UP && fd >= 0)
close(fd); close(fd);
if (ENABLE_FEATURE_CLEAN_UP && dfd >= 0)
close(dfd);
if (ENABLE_FEATURE_CLEAN_UP && lock >= 0) if (ENABLE_FEATURE_CLEAN_UP && lock >= 0)
close(lock); close(lock);
return program_ret; return program_ret;