diff options
| -rw-r--r-- | include/libbb.h | 1 | ||||
| -rw-r--r-- | libbb/time.c | 29 | ||||
| -rw-r--r-- | shell/ash.c | 12 |
3 files changed, 31 insertions, 11 deletions
diff --git a/include/libbb.h b/include/libbb.h index d74f802..7bc0dca 100644 --- a/include/libbb.h +++ b/include/libbb.h @@ -237,6 +237,7 @@ extern int *const bb_errno; #define errno (*bb_errno) #endif +unsigned long long monotonic_ns(void) FAST_FUNC; unsigned long long monotonic_us(void) FAST_FUNC; unsigned monotonic_sec(void) FAST_FUNC; diff --git a/libbb/time.c b/libbb/time.c index 7d3ac91..850ac15 100644 --- a/libbb/time.c +++ b/libbb/time.c @@ -10,8 +10,8 @@ #include "libbb.h" #if ENABLE_MONOTONIC_SYSCALL -#include <sys/syscall.h> +#include <sys/syscall.h> /* Old glibc (< 2.3.4) does not provide this constant. We use syscall * directly so this definition is safe. */ #ifndef CLOCK_MONOTONIC @@ -20,30 +20,47 @@ /* libc has incredibly messy way of doing this, * typically requiring -lrt. We just skip all this mess */ +static void get_mono(struct timespec *ts) +{ + if (syscall(__NR_clock_gettime, CLOCK_MONOTONIC, ts)) + bb_error_msg_and_die("clock_gettime(MONOTONIC) failed"); +} +unsigned long long FAST_FUNC monotonic_ns(void) +{ + struct timespec ts; + get_mono(&ts); + return ts.tv_sec * 1000000000ULL + ts.tv_nsec; +} unsigned long long FAST_FUNC monotonic_us(void) { struct timespec ts; - if (syscall(__NR_clock_gettime, CLOCK_MONOTONIC, &ts)) - bb_error_msg_and_die("clock_gettime(MONOTONIC) failed"); + get_mono(&ts); return ts.tv_sec * 1000000ULL + ts.tv_nsec/1000; } unsigned FAST_FUNC monotonic_sec(void) { struct timespec ts; - if (syscall(__NR_clock_gettime, CLOCK_MONOTONIC, &ts)) - bb_error_msg_and_die("clock_gettime(MONOTONIC) failed"); + get_mono(&ts); return ts.tv_sec; } + #else + +unsigned long long FAST_FUNC monotonic_ns(void) +{ + struct timeval tv; + gettimeofday(&tv, NULL); + return tv.tv_sec * 1000000000ULL + tv.tv_usec * 1000; +} unsigned long long FAST_FUNC monotonic_us(void) { struct timeval tv; gettimeofday(&tv, NULL); return tv.tv_sec * 1000000ULL + tv.tv_usec; } - unsigned FAST_FUNC monotonic_sec(void) { return time(NULL); } + #endif diff --git a/shell/ash.c b/shell/ash.c index 9c32162..85064d5 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -9615,7 +9615,6 @@ setcmd(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED) } #if ENABLE_ASH_RANDOM_SUPPORT -/* Roughly copied from bash.. */ static void change_random(const char *value) { @@ -9636,10 +9635,11 @@ change_random(const char *value) if (random_galois_LFSR < 0) /* if we just shifted 1 out of msb... */ t ^= MASK; random_galois_LFSR = t; - /* Both are weak, xoring them gives better randomness + /* Both are weak, combining them gives better randomness * and ~2^64 period. & 0x7fff is probably bash compat - * for $RANDOM range. */ - t = (t ^ random_LCG) & 0x7fff; + * for $RANDOM range. Combining with subtraction is + * just for fun. + and ^ would work equally well. */ + t = (t - random_LCG) & 0x7fff; /* set without recursion */ setvar(vrandom.text, utoa(t), VNOFUNC); vrandom.flags &= ~VNOFUNC; @@ -13432,7 +13432,9 @@ int ash_main(int argc ATTRIBUTE_UNUSED, char **argv) rootpid = getpid(); #if ENABLE_ASH_RANDOM_SUPPORT - random_galois_LFSR = random_LCG = rootpid + time(NULL); + /* Can use monotonic_ns() for better randomness but for now it is + * not used anywhere else in busybox... so avoid bloat */ + random_galois_LFSR = random_LCG = rootpid + monotonic_us(); #endif init(); setstackmark(&smark); |