/*
 * Copyright (c) 2006 Maxim Sobolev <sobomax@FreeBSD.org>
 * All rights reserved.
 *
 * 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 ``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 <sys/types.h>
#include <sys/uio.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <dev/powermac_nvram/powermac_nvramvar.h>

#define DEVICE_NAME     (_PATH_DEV "powermac_nvram")

static void usage(void) __dead2;
static int remove_var(uint8_t *, int, const char *);
static int append_var(uint8_t *, int, const char *, const char *);

struct deletelist {
        char *name;
        struct deletelist *next;
        struct deletelist *last;
};

static union {
        uint8_t buf[sizeof(struct chrp_header)];
        struct chrp_header header;
} conv;

int
main(int argc, char **argv)
{
        int opt, dump, fd, res, i, size;
        uint8_t buf[NVRAM_SIZE], *cp, *common;
        struct deletelist *dl;

        dump = 0;
        dl = NULL;

        while((opt = getopt(argc, argv, "d:p")) != -1) {
                switch(opt) {
                case 'p':
                        dump = 1;
                        break;

                case 'd':
                        if (dl == NULL) {
                                dl = malloc(sizeof(*dl));
                                if (dl == NULL)
                                        err(1, "malloc");
                                bzero(dl, sizeof(*dl));
                                dl->last = dl;
                        } else {
                                dl->last->next = malloc(sizeof(*dl));
                                if (dl->last->next == NULL)
                                        err(1, "malloc");
                                dl->last = dl->last->next;
                                bzero(dl->last, sizeof(*dl));
                        }
                        dl->last->name = optarg;
                        break;

                default:
                        usage();
                        /* Not reached */
                }
        }
        argc -= optind;
        argv += optind;

        if (argc == 0 && dump == 0 && dl == NULL) {
                usage();
                /* Not reached */
        }

        fd = open(DEVICE_NAME, O_RDWR);
        if (fd == -1)
                err(1, DEVICE_NAME);
        for (i = 0; i < (int)sizeof(buf);) {
                res = read(fd, buf + i, sizeof(buf) - i);
                if (res == -1 && errno != EINTR)
                        err(1, DEVICE_NAME);
                if (res == 0)
                        break;
                if (res > 0)
                        i += res;
        }
        if (i != sizeof(buf))
                errx(1, "%s: short read", DEVICE_NAME);

        /* Locate common block */
        size = 0;
        for (cp = buf; cp < buf + sizeof(buf); cp += size) {
                memcpy(conv.buf, cp, sizeof(struct chrp_header));
                size = conv.header.length * 0x10;
                if (strncmp(conv.header.name, "common", 7) == 0)
                        break;
        }
        if (cp >= buf + sizeof(buf) || size <= (int)sizeof(struct chrp_header))
                errx(1, "%s: no common block", DEVICE_NAME);
        common = cp + sizeof(struct chrp_header);
        size -= sizeof(struct chrp_header);

        if (dump != 0) {
                while (size > 0) {
                        i = strlen(common) + 1;
                        if (i == 1)
                                break;
                        printf("%s\n", common);
                        size -= i;
                        common += i;
                }
                exit(0);
        }

        for (;dl != NULL; dl = dl->next) {
                if (remove_var(common, size, dl->name) == 0)
                        warnx("%s: no such variable", dl->name);
        }

        for (; argc > 0; argc--, argv++) {
                cp = strchr(*argv, '=');
                if (cp == NULL)
                        errx(1, "%s: invalid argument", *argv);
                cp[0] = '\0';
                cp++;
                remove_var(common, size, *argv);
                if (append_var(common, size, *argv, cp) == -1)
                        errx(1, "%s: error setting variable", *argv);
        }

        for (i = 0; i < (int)sizeof(buf);) {
                res = write(fd, buf + i, sizeof(buf) - i);
                if (res == -1 && errno != EINTR)
                        err(1, DEVICE_NAME);
                if (res == 0)
                        break;
                if (res > 0)
                        i += res;
        }
        if (i != sizeof(buf))
                errx(1, "%s: short write", DEVICE_NAME);
        if (close(fd) == -1)
                err(1, DEVICE_NAME);

        exit(0);
}

static void
usage(void)
{

        fprintf(stderr, "usage: nvram [-p] | [-d name ...] [name=value ...]\n");
        exit(1);
}

static int
remove_var(uint8_t *buf, int len, const char *var_name)
{
        int nremoved, i, name_len;

        nremoved = 0;
        name_len = strlen(var_name);
        while (len > 0) {
                i = strlen(buf) + 1;
                if (i == 1)
                        break;
                if (strncmp(buf, var_name, name_len) == 0 && buf[name_len] == '=') {
                        memmove(buf, buf + i, len - i);
                        memset(buf + len - i, '\0', i);
                        nremoved += 1;
                        continue;
                }
                len -= i;
                buf += i;
        }
        return nremoved;
}

static int
append_var(uint8_t *buf, int len, const char *var_name, const char *var_value)
{
        int i, append_len;

        while (len > 0) {
                i = strlen(buf) + 1;
                if (i == 1)
                        break;
                len -= i;
                buf += i;
        }
        append_len = strlen(var_name) + strlen(var_value) + 2;
        if (len < append_len)
                return -1;
        sprintf(buf, "%s=%s", var_name, var_value);
        return 0;
}