/*
 * Tool to read/write kernel memory.
 *
 * Compile with
        cc -o kwrite kwrite.c -lkvm
 *
 * $DragonFly: src/test/debug/kwrite.c,v 1.1 2006/01/09 15:05:45 corecode Exp $
 */

#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <err.h>

static void
usage(void)
{
        fprintf(stderr, "usage: kwrite addr[/width] [bval] [bval]\n");
        exit(1);
}

int
main(int argc, char **argv)
{
        char errbuf[_POSIX2_LINE_MAX];
        kvm_t *kvm;
        unsigned long addr, width = 1, i;
        char *endptr, *endptr2;

        if (argc < 2)
                usage();

        errno = 0;
        addr = strtoul(argv[1], &endptr, 0);
        if (endptr == argv[1])
                errx(1, "no addr");
        if (errno != 0)
                err(1, "addr '%s'", argv[1]);
        switch (*endptr) {
        case 0:
                break;
        case '/':
                endptr++;
                width = strtoul(endptr, &endptr2, 0);
                if (endptr2 == endptr)
                        errx(1, "no width");
                if (errno != 0)
                        err(1, "width '%s'", endptr);
                break;
        default:
                errx(1, "invalid addr '%s'", argv[1]);
        }

        kvm = kvm_openfiles(NULL, NULL, NULL, O_RDWR, errbuf);
        if (kvm == NULL)
                errx(1, "%s", errbuf);

        if (argc < 3) {
                for (i = 0; i < width; i++) {
                        char b;

                        if (kvm_read(kvm, addr + i, &b, 1) != 1)
                                errx(1, "%s", kvm_geterr(kvm));
                        printf("%#0*lx %02x\n",
                                (int)sizeof(addr) * 2, addr + i, b);
                }
        } else {
                if (argc < width + 2)
                        errx(1, "too few values for width %ld", width);
                width = argc - 2;
                for (i = 0; i < width; i++) {
                        long v;
                        char b, bo;

                        errno = 0;
                        v = strtol(argv[2 + i], &endptr, 0);
                        if (endptr == argv[2 + i] || *endptr != 0)
                                errx(1, "invalid value '%s'", argv[2 + i]);
                        if (errno != 0 || v < 0 || v > 256) {
                                if (errno == 0) errno = ERANGE;
                                errx(1, "value '%s'", argv[2 + i]);
                        }
                        b = v;

                        if (kvm_read(kvm, addr + i, &bo, 1) != 1)
                                errx(1, "%s", kvm_geterr(kvm));
                        printf("%#0*lx %02x -> %02x\n",
                               (int)sizeof(addr) * 2, addr + i, bo, b);
                        if (kvm_write(kvm, addr + i, &b, 1) != 1)
                                errx(1, "%s", kvm_geterr(kvm));
                }
        }

        return 0;
}