/*-
 * Copyright (c) 2016 Netflix, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 <sys/cdefs.h>
#include <ctype.h>
#include <efivar.h>
#include <efivar-dp.h>
#include <err.h>
#include <errno.h>
#include <getopt.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define MAXSIZE 65536   /* Everything will be smaller than this, most 1000x smaller */

/* options descriptor */
static struct option longopts[] = {
        { "to-unix",            no_argument,            NULL,   'u' },
        { "to-efi",             no_argument,            NULL,   'e' },
        { "format",             no_argument,            NULL,   'f' },
        { "parse",              no_argument,            NULL,   'p' },
        { NULL,                 0,                      NULL,   0 }
};


static int flag_format, flag_parse, flag_unix, flag_efi;

static void
usage(void)
{

        errx(1, "efidp [-efpu]");
}

static ssize_t
read_file(int fd, void **rv) 
{
        uint8_t *retval;
        size_t len;
        off_t off;
        ssize_t red;

        len = MAXSIZE;
        off = 0;
        retval = malloc(len);
        do {
                red = read(fd, retval + off, len - off);
                if (red == 0)
                        break;
                off += red;
                if (off == (off_t)len)
                        break;
        } while (1);
        *rv = retval;

        return off;
}

static void
parse_args(int argc, char **argv)
{
        int ch;

        while ((ch = getopt_long(argc, argv, "efpu",
                    longopts, NULL)) != -1) {
                switch (ch) {
                case 'e':
                        flag_efi++;
                        break;
                case 'f':
                        flag_format++;
                        break;
                case 'p':
                        flag_parse++;
                        break;
                case 'u':
                        flag_unix++;
                        break;
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        if (argc >= 1)
                usage();
        
        if (flag_parse + flag_format + flag_efi + flag_unix != 1) {
                warnx("Can only use one of -p (--parse), "
                    "and -f (--format)");
                usage();
        }
}

static char *
trim(char *s)
{
        char *t;

        while (isspace(*s))
                s++;
        t = s + strlen(s) - 1;
        while (t > s && isspace(*t))
                *t-- = '\0';
        return s;
}

static void
unix_to_efi(void)
{
        char buffer[MAXSIZE];
        char efi[MAXSIZE];
        efidp dp;
        char *walker;
        int rv;

        dp = NULL;
        while (fgets(buffer, sizeof(buffer), stdin)) {
                walker= trim(buffer);
                free(dp);
                dp = NULL;
                rv = efivar_unix_path_to_device_path(walker, &dp);
                if (rv != 0 || dp == NULL) {
                        errno = rv;
                        warn("Can't convert '%s' to efi", walker);
                        continue;
                }
                if (efidp_format_device_path(efi, sizeof(efi),
                    dp, efidp_size(dp)) < 0) {
                        warnx("Can't format dp for '%s'", walker);
                        continue;
                }
                printf("%s\n", efi);
        }
        free(dp);
}

static void
efi_to_unix(void)
{
        char buffer[MAXSIZE];
        char dpbuf[MAXSIZE];
        efidp dp;
        char *walker, *dev, *relpath, *abspath;
        int rv;

        dp = (efidp)dpbuf;
        while (fgets(buffer, sizeof(buffer), stdin)) {
                walker= trim(buffer);
                efidp_parse_device_path(walker, dp, sizeof(dpbuf));
                rv = efivar_device_path_to_unix_path(dp, &dev, &relpath, &abspath);
                if (rv == 0)
                        printf("%s:%s %s\n", dev, relpath, abspath);
                else {
                        errno = rv;
                        warn("Can't convert '%s' to unix", walker);
                }
        }
}

static void
format(void)
{
        char buffer[MAXSIZE];
        ssize_t fmtlen;
        ssize_t len;
        void *data;
        size_t dplen;
        const_efidp dp;

        len = read_file(STDIN_FILENO, &data);
        if (len == -1)
                err(1, "read");
        dp = (const_efidp)data;
        while (len > 0) {
                dplen = efidp_size(dp);
                fmtlen = efidp_format_device_path(buffer, sizeof(buffer),
                    dp, dplen);
                if (fmtlen > 0)
                        printf("%s\n", buffer);
                len -= dplen;
                dp = (const_efidp)((const char *)dp + dplen);
        }
        free(data);
}

static void
parse(void)
{
        char buffer[MAXSIZE];
        efidp dp;
        ssize_t dplen;
        char *walker;

        dplen = MAXSIZE;
        dp = malloc(dplen);
        if (dp == NULL)
                errx(1, "Can't allocate memory.");
        while (fgets(buffer, sizeof(buffer), stdin)) {
                walker= trim(buffer);
                dplen = efidp_parse_device_path(walker, dp, dplen);
                if (dplen == -1)
                        errx(1, "Can't parse %s", walker);
                write(STDOUT_FILENO, dp, dplen);
        }
        free(dp);
}

int
main(int argc, char **argv)
{

        parse_args(argc, argv);
        if (flag_unix)
                efi_to_unix();
        else if (flag_efi)
                unix_to_efi();
        else if (flag_format)
                format();
        else if (flag_parse)
                parse();
}