linux_module_learn/examples/misc-progs/mapper.c

72 lines
2.1 KiB
C

/*
* mapper.c -- simple file that mmap()s a file region and prints 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>
#include <limits.h>
int main(int argc, char **argv)
{
char *fname;
FILE *f;
unsigned long offset, len;
void *address;
if (argc !=4
|| sscanf(argv[2],"%li", &offset) != 1
|| sscanf(argv[3],"%li", &len) != 1) {
fprintf(stderr, "%s: Usage \"%s <file> <offset> <len>\"\n", argv[0],
argv[0]);
exit(1);
}
/* the offset might be big (e.g., PCI devices), but conversion trims it */
if (offset == INT_MAX) {
if (argv[2][1]=='x')
sscanf(argv[2]+2, "%lx", &offset);
else
sscanf(argv[2], "%lu", &offset);
}
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, MAP_FILE | MAP_PRIVATE, fileno(f), offset);
if (address == (void *)-1) {
fprintf(stderr,"%s: mmap(): %s\n",argv[0],strerror(errno));
exit(1);
}
fclose(f);
fprintf(stderr, "mapped \"%s\" from %lu (0x%08lx) to %lu (0x%08lx)\n",
fname, offset, offset, offset+len, offset+len);
fwrite(address, 1, len, stdout);
return 0;
}