/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "str.h"
#include "utc-offset.h"
#include "utc-mktime.h"
#include "rfc822-parser.h"
#include "message-date.h"
#include <ctype.h>
/* RFC specifies ':' as the only allowed separator,
but be forgiving also for some broken ones */
#define IS_TIME_SEP(c) \
((c) == ':' || (c) == '.')
struct message_date_parser_context {
struct rfc822_parser_context parser;
string_t *str;
};
static const char *month_names[] = {
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static const char *weekday_names[] = {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static int parse_timezone(const unsigned char *str, size_t len)
{
int offset;
char chr;
if (len == 5 && (*str == '+' || *str == '-')) {
/* numeric offset */
if (!i_isdigit(str[1]) || !i_isdigit(str[2]) ||
!i_isdigit(str[3]) || !i_isdigit(str[4]))
return 0;
offset = ((str[1]-'0') * 10 + (str[2]-'0')) * 60 +
(str[3]-'0') * 10 + (str[4]-'0');
return *str == '+' ? offset : -offset;
}
if (len == 1) {
/* military zone - handle them the correct way, not as
RFC822 says. RFC2822 though suggests that they'd be
considered as unspecified.. */
chr = i_toupper(*str);
if (chr < 'J')
return (*str-'A'+1) * 60;
if (chr == 'J')
return 0;
if (chr <= 'M')
return (*str-'A') * 60;
if (chr < 'Z')
return ('M'-*str) * 60;
return 0;
}
if (len == 2 && i_toupper(str[0]) == 'U' && i_toupper(str[1]) == 'T') {
/* UT - Universal Time */
return 0;
}
if (len == 3) {
/* GMT | [ECMP][DS]T */
if (str[2] != 'T')
return 0;
switch (i_toupper(*str)) {
case 'E':
offset = -5 * 60;
break;
case 'C':
offset = -6 * 60;
break;
case 'M':
offset = -7 * 60;
break;
case 'P':
offset = -8 * 60;
break;
default:
/* GMT and others */
return 0;
}
if (i_toupper(str[1]) == 'D')
return offset + 60;
if (i_toupper(str[1]) == 'S')
return offset;
}
return 0;
}
static int next_token(struct message_date_parser_context *ctx,
const unsigned char **value, size_t *value_len)
{
int ret;
str_truncate(ctx->str, 0);
ret = ctx->parser.data == ctx->parser.end ? 0 :
rfc822_parse_atom(&ctx->parser, ctx->str);
*value = str_data(ctx->str);
*value_len = str_len(ctx->str);
return ret < 0 ? -1 : *value_len > 0;
}
static bool
message_date_parser_tokens(struct message_date_parser_context *ctx,
time_t *timestamp_r, int *timezone_offset_r)
{
struct tm tm;
const unsigned char *value;
size_t i, len;
int ret;
/* [weekday_name "," ] dd month_name [yy]yy hh:mi[:ss] timezone */
i_zero(&tm);
rfc822_skip_lwsp(&ctx->parser);
/* skip the optional weekday */
if (next_token(ctx, &value, &len) <= 0)
return FALSE;
if (len == 3) {
if (*ctx->parser.data != ',')
return FALSE;
ctx->parser.data++;
rfc822_skip_lwsp(&ctx->parser);
if (next_token(ctx, &value, &len) <= 0)
return FALSE;
}
/* dd */
if (len < 1 || len > 2 || !i_isdigit(value[0]))
return FALSE;
tm.tm_mday = value[0]-'0';
if (len == 2) {
if (!i_isdigit(value[1]))
return FALSE;
tm.tm_mday = (tm.tm_mday * 10) + (value[1]-'0');
}
/* month name */
if (next_token(ctx, &value, &len) <= 0 || len < 3)
return FALSE;
for (i = 0; i < 12; i++) {
if (i_memcasecmp(month_names[i], value, 3) == 0) {
tm.tm_mon = i;
break;
}
}
if (i == 12)
return FALSE;
/* [yy]yy */
if (next_token(ctx, &value, &len) <= 0 || (len != 2 && len != 4))
return FALSE;
for (i = 0; i < len; i++) {
if (!i_isdigit(value[i]))
return FALSE;
tm.tm_year = tm.tm_year * 10 + (value[i]-'0');
}
if (len == 2) {
/* two digit year, assume 1970+ */
if (tm.tm_year < 70)
tm.tm_year += 100;
} else {
if (tm.tm_year < 1900)
return FALSE;
tm.tm_year -= 1900;
}
/* hh, allow also single digit */
if (next_token(ctx, &value, &len) <= 0 ||
len < 1 || len > 2 || !i_isdigit(value[0]))
return FALSE;
tm.tm_hour = value[0]-'0';
if (len == 2) {
if (!i_isdigit(value[1]))
return FALSE;
tm.tm_hour = tm.tm_hour * 10 + (value[1]-'0');
}
/* :mm (may be the last token) */
if (!IS_TIME_SEP(*ctx->parser.data))
return FALSE;
ctx->parser.data++;
rfc822_skip_lwsp(&ctx->parser);
if (next_token(ctx, &value, &len) < 0 || len != 2 ||
!i_isdigit(value[0]) || !i_isdigit(value[1]))
return FALSE;
tm.tm_min = (value[0]-'0') * 10 + (value[1]-'0');
/* [:ss] */
if (ctx->parser.data != ctx->parser.end &&
IS_TIME_SEP(*ctx->parser.data)) {
ctx->parser.data++;
rfc822_skip_lwsp(&ctx->parser);
if (next_token(ctx, &value, &len) <= 0 || len != 2 ||
!i_isdigit(value[0]) || !i_isdigit(value[1]))
return FALSE;
tm.tm_sec = (value[0]-'0') * 10 + (value[1]-'0');
}
if ((ret = next_token(ctx, &value, &len)) < 0)
return FALSE;
if (ret == 0) {
/* missing timezone */
*timezone_offset_r = 0;
} else {
/* timezone. invalid timezones are treated as GMT, because
we may not know all the possible timezones that are used
and it's better to give at least a mostly correct reply.
FIXME: perhaps some different strict version of this
function would be useful? */
*timezone_offset_r = parse_timezone(value, len);
}
tm.tm_isdst = -1;
*timestamp_r = utc_mktime(&tm);
if (*timestamp_r == (time_t)-1)
return FALSE;
*timestamp_r -= *timezone_offset_r * 60;
return TRUE;
}
bool message_date_parse(const unsigned char *data, size_t size,
time_t *timestamp_r, int *timezone_offset_r)
{
bool success;
T_BEGIN {
struct message_date_parser_context ctx;
rfc822_parser_init(&ctx.parser, data, size, NULL);
ctx.str = t_str_new(128);
success = message_date_parser_tokens(&ctx, timestamp_r,
timezone_offset_r);
} T_END;
return success;
}
const char *message_date_create(time_t timestamp)
{
struct tm *tm;
int offset;
bool negative;
tm = localtime(&timestamp);
offset = utc_offset(tm, timestamp);
if (offset >= 0)
negative = FALSE;
else {
negative = TRUE;
offset = -offset;
}
return t_strdup_printf("%s, %02d %s %04d %02d:%02d:%02d %c%02d%02d",
weekday_names[tm->tm_wday],
tm->tm_mday,
month_names[tm->tm_mon],
tm->tm_year+1900,
tm->tm_hour, tm->tm_min, tm->tm_sec,
negative ? '-' : '+', offset / 60, offset % 60);
}