source: mainline/uspace/app/bdsh/cmds/modules/sleep/sleep.c@ c4f7bf6

/*
 * Copyright (c) 2008 Tim Post
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "config.h"
#include "util.h"
#include "errors.h"
#include "entry.h"
#include "sleep.h"
#include "cmds.h"

static const char *cmdname = "sleep";

/* Dispays help for sleep in various levels */
void help_cmd_sleep(unsigned int level)
{
        if (level == HELP_SHORT) {
                printf("`%s' pauses for a given time interval\n", cmdname);
        } else {
                help_cmd_sleep(HELP_SHORT);
                printf(
                    "Usage:  %s <duration>\n"
                    "The duration is a decimal number of seconds.\n",
                    cmdname);
        }

        return;
}

/** Convert string containing decimal seconds to useconds_t.
 *
 * @param nptr   Pointer to string.
 * @param result Result of the conversion.
 * @return EOK if conversion was successful.
 */
static int decimal_to_useconds(const char *nptr, useconds_t *result)
{
        int ret;
        uint64_t whole_seconds;
        uint64_t frac_seconds;
        char *endptr;

        /* Check for whole seconds */
        if (*nptr == '.') {
                whole_seconds = 0;
                endptr = (char *)nptr;
        } else {
                ret = str_uint64_t(nptr, &endptr, 10, false, &whole_seconds);
                if (ret != EOK)
                        return ret;
        }

        /* Check for fractional seconds */
        if (*endptr == '\0') {
                frac_seconds = 0;
        } else if (*endptr == '.' && endptr[1] == '\0') {
                frac_seconds = 0;
        } else if (*endptr == '.') {
                nptr = endptr + 1;
                ret = str_uint64_t(nptr, &endptr, 10, true, &frac_seconds);
                if (ret != EOK)
                        return ret;

                int ndigits = endptr - nptr;
                for (; ndigits < 6; ndigits++) 
                        frac_seconds *= 10;
                for (; ndigits > 6; ndigits--)
                        frac_seconds /= 10;
        } else {
                return EINVAL;
        }

        /* Check for overflow */
        useconds_t total = whole_seconds * 1000000 + frac_seconds;
        if (total / 1000000 != whole_seconds)
                return EOVERFLOW;

        *result = total;

        return EOK;
}

/* Main entry point for sleep, accepts an array of arguments */
int cmd_sleep(char **argv)
{
        int ret;
        unsigned int argc;
        useconds_t duration = 0;

        /* Count the arguments */
        argc = cli_count_args(argv);

        if (argc != 2) {
                printf("%s - incorrect number of arguments. Try `help %s'\n",
                    cmdname, cmdname);
                return CMD_FAILURE;
        }

        ret = decimal_to_useconds(argv[1], &duration);
        if (ret != EOK) {
                printf("%s - invalid duration.\n", cmdname);
                return CMD_FAILURE;
        }

        (void) usleep(duration);

        return CMD_SUCCESS;
}