/* * wmapper.c -- simple file that mmap()s a file region and writes to it * * Copyright (C) 1998,2000,2001 Alessandro Rubini *  *   This program is free software; you can redistribute it and/or modify *   it under the terms of the GNU General Public License as published by *   the Free Software Foundation; either version 2 of the License, or *   (at your option) any later version. * *   This program is distributed in the hope that it will be useful, *   but WITHOUT ANY WARRANTY; without even the implied warranty of *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the *   GNU General Public License for more details. * *   You should have received a copy of the GNU General Public License *   along with this program; if not, write to the Free Software *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. */#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/mman.h>#include <errno.h>int main(int argc, char **argv){    char *fname;    FILE *f;    unsigned int offset, len;    unsigned char *address;    int i, c;    if (argc !=4       || sscanf(argv[2],"%i", &offset) != 1       || sscanf(argv[3],"%i", &len) != 1) {        fprintf(stderr, "%s: Usage \"%s <file> <offset> <len>\"\n", argv[0],                argv[0]);        exit(1);    }    fname=argv[1];    if (!(f=fopen(fname,"r+"))) {        fprintf(stderr, "%s: %s: %s\n", argv[0], fname, strerror(errno));        exit(1);    }    address=mmap(0, len, PROT_READ | PROT_WRITE,		 MAP_FILE | MAP_SHARED, fileno(f), offset);    if (address == (void *)-1) {        fprintf(stderr,"%s: mmap(): %s\n",argv[0],strerror(errno));        exit(1);    }    fclose(f);    for (i=0; i<len; i++) {        c = getchar();        if (c==-1)            return 0;        address[i]=c;    }    return 0;}