/* * wmapper.c -- simple file that mmap()s a file region and writes to it * * Tested with 2.0 2.2 2.4  on x86 * Tested with 2.0          on SPARC * Tested with 2.0          on Alpha * Tested with     2.2      on ARM * Tested with     2.2      on PowerPC * Tested with     2.2      on SPARC64 * * Actually, it should run with any Unix */#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;}