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wireshark/epan/ftypes/ftype-time.c

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/*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 2001 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#define _GNU_SOURCE
#include "config.h"
#include "ftypes-int.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <epan/to_str.h>
#include <wsutil/time_util.h>
#include <wsutil/ws_strptime.h>
#include <wsutil/safe-math.h>
static enum ft_result
cmp_order(const fvalue_t *a, const fvalue_t *b, int *cmp)
{
*cmp = nstime_cmp(&(a->value.time), &(b->value.time));
return FT_OK;
}
/*
* Get a nanoseconds value, starting at "p".
*
* Returns true on success, false on failure.
*
* If successful endptr points to the first invalid character.
*/
static gboolean
get_nsecs(const char *startp, int *nsecs, const char **endptr)
{
int ndigits = 0;
int scale;
const char *p;
int val;
int digit;
int i;
/*
* How many digits are in the string?
*/
for (p = startp; g_ascii_isdigit(*p); p++)
ndigits++;
/*
* If there are N characters in the string, the last of the
* characters would be the digit corresponding to 10^(9-N)
* nanoseconds.
*/
scale = 9 - ndigits;
/*
* Start at the last character, and work backwards.
*/
val = 0;
while (p != startp) {
p--;
if (!g_ascii_isdigit(*p)) {
/*
* Not a digit - error.
*/
return FALSE;
}
digit = *p - '0';
if (digit != 0) {
/*
* Non-zero digit corresponding to that number
* of (10^scale) units.
*
* If scale is less than zero, this digit corresponds
* to a value less than a nanosecond, so this number
* isn't valid.
*/
if (scale < 0)
return FALSE;
for (i = 0; i < scale; i++)
digit *= 10;
val += digit;
}
scale++;
}
*nsecs = val;
if (endptr)
*endptr = startp + ndigits;
return TRUE;
}
static gboolean
val_from_unix_time(fvalue_t *fv, const char *s)
{
const char *curptr;
char *endptr;
gboolean negative = FALSE;
curptr = s;
if (*curptr == '-') {
negative = TRUE;
curptr++;
}
/*
* If it doesn't begin with ".", it should contain a seconds
* value.
*/
if (*curptr != '.') {
/*
* Get the seconds value.
*/
fv->value.time.secs = strtoul(curptr, &endptr, 10);
if (endptr == curptr || (*endptr != '\0' && *endptr != '.'))
return FALSE;
curptr = endptr;
if (*curptr == '.')
curptr++; /* skip the decimal point */
} else {
/*
* No seconds value - it's 0.
*/
fv->value.time.secs = 0;
curptr++; /* skip the decimal point */
}
/*
* If there's more stuff left in the string, it should be the
* nanoseconds value.
*/
if (*curptr != '\0') {
/*
* Get the nanoseconds value.
*/
if (!get_nsecs(curptr, &fv->value.time.nsecs, NULL))
return FALSE;
} else {
/*
* No nanoseconds value - it's 0.
*/
fv->value.time.nsecs = 0;
}
if (negative) {
fv->value.time.secs = -fv->value.time.secs;
fv->value.time.nsecs = -fv->value.time.nsecs;
}
return TRUE;
}
static gboolean
relative_val_from_literal(fvalue_t *fv, const char *s, gboolean allow_partial_value _U_, gchar **err_msg)
{
if (val_from_unix_time(fv, s))
return TRUE;
if (err_msg != NULL)
*err_msg = ws_strdup_printf("\"%s\" is not a valid time.", s);
return FALSE;
}
/*
* Parses an absolute time value from a string. The string can have
* a UTC time zone suffix. In that case it is interpreted in UTC. Otherwise
* it is interpreted in local time.
*
* OS-dependent; e.g., on 32 bit versions of Windows when compiled to use
* _mktime32 treats dates before January 1, 1970 as invalid.
* (https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/mktime-mktime32-mktime64)
*/
/*
* Timezone support:
*
%z an ISO 8601, RFC-2822, or RFC-3339 time zone specification. (A
NetBSD extension.) This is one of the following:
- The offset from Coordinated Universal Time (`UTC') speci-
fied as:
· [+-]hhmm
· [+-]hh:mm
· [+-]hh
- `UTC' specified as:
· UTC (`Coordinated Universal Time')
· GMT (`Greenwich Mean Time')
· UT (`Universal Time')
· Z (`Zulu Time')
- A three character US time zone specified as:
· EDT
· EST
· CDT
· CST
· MDT
· MST
· PDT
· PST
with the first letter standing for `Eastern' (``E''),
`Central' (``C''), `Mountain' (``M'') or `Pacific'
(``P''), and the second letter standing for `Daylight'
(``D'' or summer) time or `Standard' (``S'') time
- a single letter military or nautical time zone specified
as:
· ``A'' through ``I''
· ``K'' through ``Y''
· ``J'' (non-nautical local time zone)
%Z time zone name or no characters when time zone information is
unavailable. (A NetBSD extension.)
*/
/*
* POSIX and C11 calendar time APIs are limited, poorly documented and have
* loads of bagage and surprising behavior and quirks (most stemming from
* the fact that the struct tm argument is sometimes both input and output).
* See the following reference for a reliable method of handling arbitrary timezones:
* C: Converting struct tm times with timezone to time_t
* http://kbyanc.blogspot.com/2007/06/c-converting-struct-tm-times-with.html
* Relevant excerpt:
* "However, if your libc implements both tm_gmtoff and timegm(3) you are
* in luck. You just need to use timegm(3) to get the time_t representing
* the time in GMT and then subtract the offset stored in tm_gmtoff.
* The tricky part is that calling timegm(3) will modify the struct tm,
* clearing the tm_gmtoff field to zero."
*/
#define EXAMPLE "Example: \"Nov 12, 1999 08:55:44.123\" or \"2011-07-04 12:34:56\""
static gboolean
absolute_val_from_string(fvalue_t *fv, const char *s, size_t len _U_, char **err_msg_ptr)
{
struct tm tm;
const char *bufptr, *curptr = NULL;
const char *endptr;
gboolean has_seconds = TRUE;
gboolean has_timezone = TRUE;
char *err_msg = NULL;
struct ws_timezone zoneinfo = { 0, NULL };
/* Try Unix time first. */
if (val_from_unix_time(fv, s))
return TRUE;
/* Try ISO 8601 format. */
endptr = iso8601_to_nstime(&fv->value.time, s, ISO8601_DATETIME);
/* Check whether it parsed all of the string */
if (endptr != NULL && *endptr == '\0')
return TRUE;
/* No - try other legacy formats. */
memset(&tm, 0, sizeof(tm));
/* Let the computer figure out if it's DST. */
tm.tm_isdst = -1;
/* Parse the date. ws_strptime() always uses the "C" locale. */
bufptr = s;
curptr = ws_strptime(bufptr, "%b %d, %Y", &tm, &zoneinfo);
if (curptr == NULL)
curptr = ws_strptime(bufptr,"%Y-%m-%d", &tm, &zoneinfo);
if (curptr == NULL)
goto fail;
/* Parse the time, it is optional. */
bufptr = curptr;
curptr = ws_strptime(bufptr, " %H:%M:%S", &tm, &zoneinfo);
if (curptr == NULL) {
has_seconds = FALSE;
/* Seconds can be omitted but minutes (and hours) are required
* for a valid time value. */
curptr = ws_strptime(bufptr," %H:%M", &tm, &zoneinfo);
}
if (curptr == NULL)
curptr = bufptr;
if (*curptr == '.') {
/* Nanoseconds */
if (!has_seconds) {
err_msg = ws_strdup("Subsecond precision requires a seconds field.");
goto fail; /* Requires seconds */
}
curptr++; /* skip the "." */
if (!g_ascii_isdigit((unsigned char)*curptr)) {
/* not a digit, so not valid */
err_msg = ws_strdup("Subseconds value is not a number.");
goto fail;
}
if (!get_nsecs(curptr, &fv->value.time.nsecs, &endptr)) {
err_msg = ws_strdup("Subseconds value is invalid.");
goto fail;
}
curptr = endptr;
}
else {
/*
* No nanoseconds value - it's 0.
*/
fv->value.time.nsecs = 0;
}
/* Timezone */
bufptr = curptr;
curptr = ws_strptime(bufptr, "%n%z", &tm, &zoneinfo);
if (curptr == NULL) {
/* No timezone, assume localtime. */
has_timezone = FALSE;
curptr = bufptr;
}
/* Skip whitespace */
while (g_ascii_isspace(*curptr)) {
curptr++;
}
if (*curptr != '\0') {
err_msg = ws_strdup("Unexpected data after time value.");
goto fail;
}
if (has_timezone) {
/* Convert our calendar time (presumed in UTC, possibly with
* an extra timezone offset correction datum) to epoch time. */
fv->value.time.secs = mktime_utc(&tm);
}
else {
/* Convert our calendar time (in the local timezone) to epoch time. */
fv->value.time.secs = mktime(&tm);
}
if (fv->value.time.secs == (time_t)-1) {
/*
* XXX - should we supply an error message that mentions
* that the time specified might be syntactically valid
* but might not actually have occurred, e.g. a time in
* the non-existent time range after the clocks are
* set forward during daylight savings time (or possibly
* that it's in the time range after the clocks are set
* backward, so that there are two different times that
* it could be)?
*/
err_msg = ws_strdup_printf("\"%s\" cannot be converted to a valid calendar time.", s);
goto fail;
}
if (has_timezone) {
/* Normalize to UTC with the offset we have saved. */
fv->value.time.secs -= zoneinfo.tm_gmtoff;
}
return TRUE;
fail:
if (err_msg_ptr != NULL) {
if (err_msg == NULL) {
*err_msg_ptr = ws_strdup_printf("\"%s\" is not a valid absolute time. " EXAMPLE, s);
}
else {
*err_msg_ptr = err_msg;
}
}
else {
g_free(err_msg);
}
return FALSE;
}
static gboolean
absolute_val_from_literal(fvalue_t *fv, const char *s, gboolean allow_partial_value _U_, gchar **err_msg)
{
return absolute_val_from_string(fv, s, 0, err_msg);
}
static void
time_fvalue_new(fvalue_t *fv)
{
fv->value.time.secs = 0;
fv->value.time.nsecs = 0;
}
static void
time_fvalue_copy(fvalue_t *dst, const fvalue_t *src)
{
nstime_copy(&dst->value.time, &src->value.time);
}
static void
time_fvalue_set(fvalue_t *fv, const nstime_t *value)
{
fv->value.time = *value;
}
static const nstime_t *
value_get(fvalue_t *fv)
{
return &(fv->value.time);
}
static char *
abs_time_to_ftrepr_dfilter(wmem_allocator_t *scope,
const nstime_t *nstime, bool use_utc)
{
struct tm *tm;
char datetime_format[128];
char nsecs_buf[32];
if (use_utc) {
tm = gmtime(&nstime->secs);
if (tm != NULL)
strftime(datetime_format, sizeof(datetime_format), "\"%Y-%m-%d %H:%M:%S%%sZ\"", tm);
else
snprintf(datetime_format, sizeof(datetime_format), "Not representable");
}
else {
tm = localtime(&nstime->secs);
/* Displaying the timezone could be made into a preference. */
if (tm != NULL)
strftime(datetime_format, sizeof(datetime_format), "\"%Y-%m-%d %H:%M:%S%%s%z\"", tm);
else
snprintf(datetime_format, sizeof(datetime_format), "Not representable");
}
if (nstime->nsecs == 0)
return wmem_strdup_printf(scope, datetime_format, "");
snprintf(nsecs_buf, sizeof(nsecs_buf), ".%09d", nstime->nsecs);
return wmem_strdup_printf(scope, datetime_format, nsecs_buf);
}
static char *
absolute_val_to_repr(wmem_allocator_t *scope, const fvalue_t *fv, ftrepr_t rtype, int field_display)
{
char *rep;
if (field_display == BASE_NONE)
field_display = ABSOLUTE_TIME_LOCAL;
switch (rtype) {
case FTREPR_DISPLAY:
rep = abs_time_to_str_ex(scope, &fv->value.time,
field_display, ABS_TIME_TO_STR_SHOW_ZONE);
break;
case FTREPR_DFILTER:
if (field_display == ABSOLUTE_TIME_UNIX) {
rep = abs_time_to_unix_str(scope, &fv->value.time);
}
else {
/* Only ABSOLUTE_TIME_LOCAL and ABSOLUTE_TIME_UTC
* are supported. Normalize the field_display value. */
if (field_display != ABSOLUTE_TIME_LOCAL)
field_display = ABSOLUTE_TIME_UTC;
rep = abs_time_to_ftrepr_dfilter(scope, &fv->value.time, field_display != ABSOLUTE_TIME_LOCAL);
}
break;
default:
ws_assert_not_reached();
break;
}
return rep;
}
static char *
relative_val_to_repr(wmem_allocator_t *scope, const fvalue_t *fv, ftrepr_t rtype _U_, int field_display _U_)
{
return rel_time_to_secs_str(scope, &fv->value.time);
}
static guint
time_hash(const fvalue_t *fv)
{
return nstime_hash(&fv->value.time);
}
static gboolean
time_is_zero(const fvalue_t *fv)
{
return nstime_is_zero(&fv->value.time);
}
static gboolean
time_is_negative(const fvalue_t *fv)
{
return fv->value.time.secs < 0;
}
static enum ft_result
time_unary_minus(fvalue_t * dst, const fvalue_t *src, char **err_ptr _U_)
{
dst->value.time.secs = -src->value.time.secs;
dst->value.time.nsecs = -src->value.time.nsecs;
return FT_OK;
}
#define NS_PER_S 1000000000
static void
check_ns_wraparound(nstime_t *ns, jmp_buf env)
{
if (ns->nsecs >= NS_PER_S || (ns->nsecs > 0 && ns->secs < 0)) {
ws_safe_sub_jmp(&ns->nsecs, ns->nsecs, NS_PER_S, env);
ws_safe_add_jmp(&ns->secs, ns->secs, 1, env);
}
else if(ns->nsecs <= -NS_PER_S || (ns->nsecs < 0 && ns->secs > 0)) {
ws_safe_add_jmp(&ns->nsecs, ns->nsecs, NS_PER_S, env);
ws_safe_sub_jmp(&ns->secs, ns->secs, 1, env);
}
}
static void
_nstime_add(nstime_t *res, nstime_t a, const nstime_t b, jmp_buf env)
{
ws_safe_add_jmp(&res->secs, a.secs, b.secs, env);
ws_safe_add_jmp(&res->nsecs, a.nsecs, b.nsecs, env);
check_ns_wraparound(res, env);
}
static void
_nstime_sub(nstime_t *res, nstime_t a, const nstime_t b, jmp_buf env)
{
ws_safe_sub_jmp(&res->secs, a.secs, b.secs, env);
ws_safe_sub_jmp(&res->nsecs, a.nsecs, b.nsecs, env);
check_ns_wraparound(res, env);
}
static enum ft_result
time_add(fvalue_t * dst, const fvalue_t *a, const fvalue_t *b, char **err_ptr)
{
jmp_buf env;
if (setjmp(env) != 0) {
*err_ptr = ws_strdup_printf("time_add: overflow");
return FT_ERROR;
}
_nstime_add(&dst->value.time, a->value.time, b->value.time, env);
return FT_OK;
}
static enum ft_result
time_subtract(fvalue_t * dst, const fvalue_t *a, const fvalue_t *b, char **err_ptr)
{
jmp_buf env;
if (setjmp(env) != 0) {
*err_ptr = ws_strdup_printf("time_subtract: overflow");
return FT_ERROR;
}
_nstime_sub(&dst->value.time, a->value.time, b->value.time, env);
return FT_OK;
}
void
ftype_register_time(void)
{
static ftype_t abstime_type = {
FT_ABSOLUTE_TIME, /* ftype */
"FT_ABSOLUTE_TIME", /* name */
"Date and time", /* pretty_name */
0, /* wire_size */
time_fvalue_new, /* new_value */
time_fvalue_copy, /* copy_value */
NULL, /* free_value */
absolute_val_from_literal, /* val_from_literal */
absolute_val_from_string, /* val_from_string */
NULL, /* val_from_charconst */
absolute_val_to_repr, /* val_to_string_repr */
NULL, /* val_to_uinteger64 */
NULL, /* val_to_sinteger64 */
{ .set_value_time = time_fvalue_set }, /* union set_value */
{ .get_value_time = value_get }, /* union get_value */
cmp_order,
NULL, /* cmp_contains */
NULL, /* cmp_matches */
time_hash, /* hash */
time_is_zero, /* is_zero */
time_is_negative, /* is_negative */
NULL,
NULL,
NULL, /* bitwise_and */
time_unary_minus, /* unary_minus */
time_add, /* add */
time_subtract, /* subtract */
NULL, /* multiply */
NULL, /* divide */
NULL, /* modulo */
};
static ftype_t reltime_type = {
FT_RELATIVE_TIME, /* ftype */
"FT_RELATIVE_TIME", /* name */
"Time offset", /* pretty_name */
0, /* wire_size */
time_fvalue_new, /* new_value */
time_fvalue_copy, /* copy_value */
NULL, /* free_value */
relative_val_from_literal, /* val_from_literal */
NULL, /* val_from_string */
NULL, /* val_from_charconst */
relative_val_to_repr, /* val_to_string_repr */
NULL, /* val_to_uinteger64 */
NULL, /* val_to_sinteger64 */
{ .set_value_time = time_fvalue_set }, /* union set_value */
{ .get_value_time = value_get }, /* union get_value */
cmp_order,
NULL, /* cmp_contains */
NULL, /* cmp_matches */
time_hash, /* hash */
time_is_zero, /* is_zero */
time_is_negative, /* is_negative */
NULL,
NULL,
NULL, /* bitwise_and */
time_unary_minus, /* unary_minus */
time_add, /* add */
time_subtract, /* subtract */
NULL, /* multiply */
NULL, /* divide */
NULL, /* modulo */
};
ftype_register(FT_ABSOLUTE_TIME, &abstime_type);
ftype_register(FT_RELATIVE_TIME, &reltime_type);
}
void
ftype_register_pseudofields_time(int proto)
{
static int hf_ft_rel_time;
static int hf_ft_abs_time;
static hf_register_info hf_ftypes[] = {
{ &hf_ft_abs_time,
{ "FT_ABSOLUTE_TIME", "_ws.ftypes.abs_time",
FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC, NULL, 0x00,
NULL, HFILL }
},
{ &hf_ft_rel_time,
{ "FT_RELATIVE_TIME", "_ws.ftypes.rel_time",
FT_RELATIVE_TIME, BASE_NONE, NULL, 0x00,
NULL, HFILL }
},
};
proto_register_field_array(proto, hf_ftypes, array_length(hf_ftypes));
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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