util.cpp

#include "util.h"

#include <climits>
#include <cstdio>

#include "Enclave_t.h"
#include "sgx_lfence.h"

int printf(const char *fmt, ...) {
  char buf[BUFSIZ] = {'\0'};
  va_list ap;
  va_start(ap, fmt);
  int ret = vsnprintf(buf, BUFSIZ, fmt, ap);
  va_end(ap);
  ocall_print_string(buf);
  return ret;
}

/** From https://stackoverflow.com/a/8362718 */
std::string string_format(const std::string &fmt, ...) {
    int size=BUFSIZ;
    std::string str;
    va_list ap;
    while (1) {
        str.resize(size);
        va_start(ap, fmt);
        int n = vsnprintf(&str[0], size, fmt.c_str(), ap);
        va_end(ap);
        if (n > -1 && n < size)
            return str;
        if (n > -1)
            size = n + 1;
        else
            size *= 2;
    }
}

void exit(int exit_code) {
  ocall_exit(exit_code);
}

void ocall_malloc(size_t size, uint8_t **ret) {
  unsafe_ocall_malloc(size, ret);

  // Guard against overwriting enclave memory
  assert(sgx_is_outside_enclave(*ret, size) == 1);
  sgx_lfence();
}

void print_bytes(uint8_t *ptr, uint32_t len) {
  for (uint32_t i = 0; i < len; i++) {
    printf("%u", *(ptr + i));
    printf(" - ");
  }

  printf("\n");
}

int cmp(const uint8_t *value1, const uint8_t *value2, uint32_t len) {
  for (uint32_t i = 0; i < len; i++) {
    if (*(value1+i) != *(value2+i)) {
      return -1;
    }
  }
  return 0;
}

// basically a memset 0
void clear(uint8_t *dest, uint32_t len) {
  for (uint32_t i = 0; i < len; i++) {
    *(dest + i) = 0;
  }
}

/// From http://git.musl-libc.org/cgit/musl/tree/src/time/__secs_to_tm.c?h=v0.9.15
/* 2000-03-01 (mod 400 year, immediately after feb29 */
#define LEAPOCH (946684800LL + 86400*(31+29))
#define DAYS_PER_400Y (365*400 + 97)
#define DAYS_PER_100Y (365*100 + 24)
#define DAYS_PER_4Y   (365*4   + 1)
int secs_to_tm(long long t, struct tm *tm) {
  long long days, secs;
  int remdays, remsecs, remyears;
  int qc_cycles, c_cycles, q_cycles;
  int years, months;
  int wday, yday, leap;
  static const char days_in_month[] = {31,30,31,30,31,31,30,31,30,31,31,29};

  /* Reject time_t values whose year would overflow int */
  if (t < INT_MIN * 31622400LL || t > INT_MAX * 31622400LL)
    return -1;

  secs = t - LEAPOCH;
  days = secs / 86400;
  remsecs = secs % 86400;
  if (remsecs < 0) {
    remsecs += 86400;
    days--;
  }

  wday = (3+days)%7;
  if (wday < 0) wday += 7;

  qc_cycles = days / DAYS_PER_400Y;
  remdays = days % DAYS_PER_400Y;
  if (remdays < 0) {
    remdays += DAYS_PER_400Y;
    qc_cycles--;
  }

  c_cycles = remdays / DAYS_PER_100Y;
  if (c_cycles == 4) c_cycles--;
  remdays -= c_cycles * DAYS_PER_100Y;

  q_cycles = remdays / DAYS_PER_4Y;
  if (q_cycles == 25) q_cycles--;
  remdays -= q_cycles * DAYS_PER_4Y;

  remyears = remdays / 365;
  if (remyears == 4) remyears--;
  remdays -= remyears * 365;

  leap = !remyears && (q_cycles || !c_cycles);
  yday = remdays + 31 + 28 + leap;
  if (yday >= 365+leap) yday -= 365+leap;

  years = remyears + 4*q_cycles + 100*c_cycles + 400*qc_cycles;

  for (months=0; days_in_month[months] <= remdays; months++)
    remdays -= days_in_month[months];

  if (years+100 > INT_MAX || years+100 < INT_MIN)
    return -1;

  tm->tm_year = years + 100;
  tm->tm_mon = months + 2;
  if (tm->tm_mon >= 12) {
    tm->tm_mon -=12;
    tm->tm_year++;
  }
  tm->tm_mday = remdays + 1;
  tm->tm_wday = wday;
  tm->tm_yday = yday;

  tm->tm_hour = remsecs / 3600;
  tm->tm_min = remsecs / 60 % 60;
  tm->tm_sec = remsecs % 60;

  return 0;
}