/**
* Copyright © 2015 Mattias Andrée <maandree@member.fsf.org>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#define _DEFAULT_SOURCE
#include "parse_time.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <limits.h>
/**
* The number of seconds in a day.
*/
#define ONE_DAY (time_t)(24 * 60 * 60)
/**
* Set errno and return.
*
* @return e:int The error number.
*/
#define FAIL(e) return errno = (e), -1
/**
* `a *= b` with overflow check.
*/
#define MUL(a, b) if (a > timemax / (b)) FAIL(ERANGE); else a *= (b)
/**
* `a += b` with overflow check.
*/
#define ADD(a, b) if (a > timemax - (b)) FAIL(ERANGE); else a += (b)
/**
* The name of the process.
*/
extern char *argv0;
/**
* The highest value that can be stored in `time_t`.
*/
const time_t timemax = (sizeof(time_t) == sizeof(long long int)) ? LLONG_MAX : LONG_MAX;
/**
* Wrapper for `strtoll` and `strtol` that selects
* the appropriate function for `time_t`, does not
* allow whitespace or signs. It also forces the
* base to be 10, and will only return 0 on error,
* and will set `errno` on success.
*
* @param str Please see strtol(3), first parameter.
* @param end Please see strtol(3), second parameter.
* @return Please see strtol(3), only 0 may be
* returned at error.
*
* @throws 0 On success.
* @throws Please see strtol(3).
*/
static time_t
strtotime(const char *str, const char **end)
{
time_t rc;
long long int rcll;
long int rcl;
char **end_ = (char **)end;
if (!isdigit(*str))
FAIL(EINVAL);
/* The outer if-statement is for when `time_t` is update to `long long int`.
* which is need to avoid the year 2038 problem. Be we have to use `strtol`
* if `time_t` is `long int`, otherwise we will not detect overflow. */
errno = 0;
if (sizeof(time_t) == sizeof(long long int)) {
rcll = strtoll(str, end_, 10);
rc = (time_t)rcll;
} else {
rcl = strtol(str, end_, 10);
rc = (time_t)rcl;
}
return errno ? 0 : rc;
}
/**
* Parse a time on the format HH:MM[:SS].
*
* @param str The time string.
* @param ts Output parameter for the POSIX time the string
* represents.
* @param end Output parameter for the end of the parsing of `str`.
* @return 0 on success, -1 on error.
*
* @throws EINVAL `str` could not be parsed.
* @throws ERANGE `str` specifies a time beyond what can be stored.
*/
static int
parse_time_time(const char *str, struct timespec *ts, const char **end)
{
time_t t;
memset(ts, 0, sizeof(*ts));
ts->tv_sec = strtotime(str, end), str = *end;
if (errno)
return -1;
/* Must not be restricted to 23, beyond 24 is legal. */
MUL(ts->tv_sec, (time_t)(60 * 60));
if (*str++ != ':')
FAIL(EINVAL);
t = strtotime(str, end), str = *end;
if (errno)
return -1;
if (t >= 60)
FAIL(EINVAL);
MUL(t, (time_t)60);
ADD(ts->tv_sec, t);
switch (*str++) {
case 0: return 0;
case ':': break;
default: FAIL(EINVAL);
}
t = strtotime(str, end), str = *end;
if (errno)
return -1;
/* Do not restrict to 59, or 60, there can be more than +1 leap second. */
ADD(ts->tv_sec, t);
return 0;
}
/**
* Parse a time with only a second-count.
*
* @param str The time string.
* @param ts Output parameter for the POSIX time the string
* represents.
* @param end Output parameter for the end of the parsing of `str`.
* @return 0 on success, -1 on error.
*
* @throws EINVAL `str` could not be parsed.
* @throws ERANGE `str` specifies a time beyond what can be stored.
*/
static int
parse_time_seconds(const char *str, struct timespec *ts, const char **end)
{
memset(ts, 0, sizeof(*ts));
ts->tv_sec = strtotime(str, end);
if (errno)
return -1;
return 0;
}
/**
* Trivial time-parsing.
*
* @param str The time string.
* @param ts Output parameter for the POSIX time the string
* represents. If the time is in the pasted, but
* within a day, one day is added. This is in case
* you are using a external parser that did not
* release they you wanted a future time but
* thought you wanted the time to be the closed or
* in the same day.
* @param clk Output parameter for the clock in which the
* returned time is specified.
* @return 0 on success, -1 on error.
*
* @throws EINVAL `str` could not be parsed.
* @throws ERANGE `str` specifies a time beyond what can be stored.
* @throws EDOM The specified the was over a day ago.
*
* @futuredirection Add environment variable that allows
* parsing through another program.
*/
int
parse_time(const char *str, struct timespec *ts, clockid_t *clk)
{
struct timespec now;
int points, plus = *str == '+';
const char *start = str;
const char *end;
time_t adj;
/* Get current time and clock. */
clock_gettime(CLOCK_REALTIME, &now);
*clk = plus ? CLOCK_BOOTTIME : CLOCK_REALTIME;
/* Mañana? */
if (!strcmp(str, "mañana")) { /* Do not documented. */
ts->tv_sec = now.tv_sec + ONE_DAY;
ts->tv_nsec = now.tv_nsec;
return 0;
}
/* HH:MM[:SS[.NNNNNNNNN]] or seconds? */
if (strchr(str, ':')) {
if (parse_time_time(str, ts, &end))
return -1;
adj = now.tv_sec - (now.tv_sec % ONE_DAY);
ADD(ts->tv_sec, adj); /* In case the HH is really large. */
} else {
if (parse_time_seconds(str + plus, ts, &end))
return -1;
}
str = end;
/* Any fractions of a second? */
switch (*str) {
case 0: return 0;
case '.': break;
default: FAIL(EINVAL);
}
/* Parse up to nanosecond resolution. */
for (points = 0; isdigit(*str); points++) {
if (points < 9) {
ts->tv_nsec *= 10;
ts->tv_nsec += *str++ & 15;
} else if ((points == 10) && (*str >= '5')) {
ts->tv_nsec += 1;
}
}
if (ts->tv_nsec > 999999999L) {
ts->tv_sec += 1;
ts->tv_nsec = 0;
}
/* Check for error at end, and missing explicit UTC. */
if (*str) {
if (*clk == CLOCK_BOOTTIME)
FAIL(EINVAL);
while (*str == ' ') str++;
if (!strcasecmp(str, "Z") && !strcasecmp(str, "UTC"))
FAIL(EINVAL);
} else if (*clk == CLOCK_REALTIME) {
fprintf(stderr,
"%s: warning: parsing as UTC, you can avoid "
"this warning by adding a 'Z' at the end of "
"the time argument.\n", argv0);
}
/* Adjust the day? */
if (*clk == CLOCK_BOOTTIME)
return 0;
if (ts->tv_sec < now.tv_sec) { /* Ignore partial second. */
ts->tv_sec += ONE_DAY;
if (ts->tv_sec < now.tv_sec)
FAIL(EDOM);
if (!strchr(start, ':'))
fprintf(stderr,
"%s: warning: the specified time is in the past, "
"it is being adjust to be tomorrow instead.\n", argv0);
}
return 0;
}
