iolog_timing.c

/*
 * SPDX-License-Identifier: ISC
 *
 * Copyright (c) 2009-2020 Todd C. Miller <[email protected]>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_STDBOOL_H
# include <stdbool.h>
#else
# include <compat/stdbool.h>
#endif /* HAVE_STDBOOL_H */
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <fcntl.h>
#include <time.h>

#include <sudo_compat.h>
#include <sudo_debug.h>
#include <sudo_eventlog.h>
#include <sudo_fatal.h>
#include <sudo_gettext.h>
#include <sudo_iolog.h>
#include <sudo_util.h>

static int timing_event_adj;

void
iolog_adjust_delay(struct timespec *delay, struct timespec *max_delay,
     double scale_factor)
{
    debug_decl(iolog_adjust_delay, SUDO_DEBUG_UTIL);

    /* Avoid division by zero or negative delays. */
    if (scale_factor <= 0.0) {
	sudo_timespecclear(delay);
	debug_return;
    }

    if (scale_factor != 1.0) {
	/* Order is important: we don't want to double the remainder. */
	const double seconds = (double)delay->tv_sec / scale_factor;
	const double nseconds = (double)delay->tv_nsec / scale_factor;
        delay->tv_sec = (time_t)seconds;
        delay->tv_nsec = (long)nseconds;
        delay->tv_nsec += (long)((seconds - (double)delay->tv_sec) * 1000000000);
        while (delay->tv_nsec >= 1000000000) {
            delay->tv_sec++;
            delay->tv_nsec -= 1000000000;
        }
    }

    /* Clamp to max delay. */
    if (max_delay != NULL) {
	if (sudo_timespeccmp(delay, max_delay, >)) {
	    delay->tv_sec = max_delay->tv_sec;
	    delay->tv_nsec = max_delay->tv_nsec;
	}
    }

    debug_return;
}

/*
 * Parse the delay as seconds and nanoseconds: %lld.%09ld
 * Sudo used to write this as a double, but since timing data is logged
 * in the C locale this may not match the current locale.
 */
char *
iolog_parse_delay(const char *cp, struct timespec *delay,
    const char *decimal_point)
{
    char numbuf[STRLEN_MAX_SIGNED(long long) + 1];
    const char *errstr, *ep;
    long long llval;
    size_t len;
    debug_decl(iolog_parse_delay, SUDO_DEBUG_UTIL);

    /* Parse seconds (whole number portion). */
    for (ep = cp; isdigit((unsigned char)*ep); ep++)
	continue;
    len = (size_t)(ep - cp);
    if (len >= sizeof(numbuf)) {
	sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
	    "%s: number of seconds is too large", cp);
	debug_return_ptr(NULL);
    }
    memcpy(numbuf, cp, len);
    numbuf[len] = '\0';
    delay->tv_sec = (time_t)sudo_strtonum(numbuf, 0, TIME_T_MAX, &errstr);
    if (errstr != NULL) {
	sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
	    "%s: number of seconds is %s", numbuf, errstr);
	debug_return_ptr(NULL);
    }

    /* Radix may be in user's locale for sudo < 1.7.4 so accept that too. */
    if (*ep != '.' && *ep != *decimal_point) {
	if (*ep == '\0' || isspace((unsigned char)*ep)) {
	    /* No fractional part. */
	    delay->tv_nsec = 0;
	    goto done;
	}
	sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
	    "invalid characters after seconds: %s", ep);
	debug_return_ptr(NULL);
    }
    cp = ep + 1;

    /* Parse fractional part, we may read more precision than we can store. */
    for (ep = cp; isdigit((unsigned char)*ep); ep++)
	continue;
    len = (size_t)(ep - cp);
    if (len >= sizeof(numbuf)) {
	sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
	    "%s: number of nanoseconds is too large", cp);
	debug_return_ptr(NULL);
    }
    memcpy(numbuf, cp, len);
    numbuf[len] = '\0';
    llval = sudo_strtonum(numbuf, 0, LLONG_MAX, &errstr);
    if (errstr != NULL) {
	sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
	    "%s: number of nanoseconds is %s", numbuf, errstr);
	debug_return_ptr(NULL);
    }

    /* Adjust fractional part to nanosecond precision. */
    if (len < 9) {
	/* Convert to nanosecond precision. */
	do {
	    llval *= 10;
	} while (++len < 9);
    } else if (len > 9) {
	/* Clamp to nanoseconds. */
	do {
	    llval /= 10;
	} while (--len > 9);
    }
    delay->tv_nsec = (long)llval;

done:
    /* Advance to the next field. */
    while (isspace((unsigned char)*ep))
	ep++;

    debug_return_str((char *)ep);
}

/*
 * Parse a timing line, which is formatted as:
 *	IO_EVENT_TTYOUT sleep_time num_bytes
 *	IO_EVENT_WINSIZE sleep_time lines cols
 *	IO_EVENT_SUSPEND sleep_time signo
 * Where type is IO_EVENT_*, sleep_time is the number of seconds to sleep
 * before writing the data and num_bytes is the number of bytes to output.
 * Returns true on success and false on failure.
 */
bool
iolog_parse_timing(const char *line, struct timing_closure *timing)
{
    unsigned long ulval;
    char *cp, *ep;
    debug_decl(iolog_parse_timing, SUDO_DEBUG_UTIL);

    /* Clear iolog descriptor. */
    timing->iol = NULL;

    /* Parse event type. */
    ulval = strtoul(line, &ep, 10);
    if (ep == line || !isspace((unsigned char) *ep))
	goto bad;
    if (ulval >= IO_EVENT_COUNT)
	goto bad;
    if (ulval == IO_EVENT_TTYOUT_1_8_7) {
	/* work around a bug in timing files generated by sudo 1.8.7 */
	timing_event_adj = 2;
    }
    timing->event = (int)ulval - timing_event_adj;
    for (cp = ep + 1; isspace((unsigned char) *cp); cp++)
	continue;

    /* Parse delay, returns the next field or NULL on error. */
    if ((cp = iolog_parse_delay(cp, &timing->delay, timing->decimal)) == NULL)
	goto bad;

    switch (timing->event) {
    case IO_EVENT_SUSPEND:
	/* Signal name (no leading SIG prefix) or number. */
	if (str2sig(cp, &timing->u.signo) == -1)
	    goto bad;
	break;
    case IO_EVENT_WINSIZE:
	ulval = strtoul(cp, &ep, 10);
	if (ep == cp || !isspace((unsigned char) *ep))
	    goto bad;
	if (ulval > INT_MAX)
	    goto bad;
	timing->u.winsize.lines = (int)ulval;
	for (cp = ep + 1; isspace((unsigned char) *cp); cp++)
	    continue;

	ulval = strtoul(cp, &ep, 10);
	if (ep == cp || *ep != '\0')
	    goto bad;
	if (ulval > INT_MAX)
	    goto bad;
	timing->u.winsize.cols = (int)ulval;
	break;
    default:
	errno = 0;
	ulval = strtoul(cp, &ep, 10);
	if (ep == cp || *ep != '\0')
	    goto bad;
	/* Note: assumes SIZE_MAX == ULONG_MAX */
	if (errno == ERANGE && ulval == ULONG_MAX)
	    goto bad;
	timing->u.nbytes = (size_t)ulval;
	break;
    }

    debug_return_bool(true);
bad:
    debug_return_bool(false);
}

/*
 * Read the next record from the timing file.
 * Return 0 on success, 1 on EOF and -1 on error.
 */
int
iolog_read_timing_record(struct iolog_file *iol, struct timing_closure *timing)
{
    char line[LINE_MAX];
    const char *errstr;
    char *nl;
    debug_decl(iolog_read_timing_record, SUDO_DEBUG_UTIL);

    /* Read next record from timing file. */
    if (iolog_gets(iol, line, sizeof(line), &errstr) == NULL) {
	/* EOF or error reading timing file, we are done. */
	if (iolog_eof(iol))
	    debug_return_int(1);
	sudo_warnx(U_("error reading timing file: %s"), errstr);
	debug_return_int(-1);
    }

    /*
     * All timing file records must end with a newline.
     * A missing newline may indicate a line longer than LINE_MAX.
     */
    nl = strchr(line, '\n');
    if (nl == NULL) {
	goto invalid;
    }
    *nl = '\0';

    /* Parse timing file record. */
    if (!iolog_parse_timing(line, timing)) {
	goto invalid;
    }

    debug_return_int(0);
invalid:
    /* Truncate invalid timing file line at 128 bytes. */
    line[128] = '\0';
    sudo_warnx(U_("invalid timing file line: %s"), line);
    debug_return_int(-1);
}