123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899 |
- /*
- *
- * Copyright (c) 2003 The Regents of the University of California. All
- * rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * - Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * - Neither the name of the University nor the names of its
- * contributors may be used to endorse or promote products derived
- * from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR
- * CONTRIBUTORS 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.
- *
- */
-
- /*
- * FUSD - The Framework for UserSpace Devices - Example program
- *
- * Jeremy Elson <jelson@circlemud.org>
- *
- * console-read: This example demonstrates the easiest possible way to
- * block a client system call: by blocking the driver itself. Not
- * recommended for anything but the most trivial drivers -- if you
- * need a template from which to start on a real driver, use pager.c
- * instead.
- *
- * $Id: console-read.c 12351 2007-01-19 07:22:54Z xiphmont $
- */
- #include <stdio.h>
- #include <string.h>
- #include <errno.h>
- #include "fusd.h"
- #define MIN(x, y) ((x) < (y) ? (x) : (y))
- int do_open_or_close(struct fusd_file_info *file)
- {
- return 0; /* attempts to open and close this file always succeed */
- }
- /* EXAMPLE START console-read.c */
- ssize_t do_read(struct fusd_file_info *file, char *user_buffer,
- size_t user_length, loff_t *offset)
- {
- char buf[128];
-
- if (*offset > 0)
- return 0;
- /* print a prompt */
- printf("Got a read from pid %d. What do we say?\n> ", file->pid);
- fflush(stdout);
- /* get a response from the console */
- if (fgets(buf, sizeof(buf) - 1, stdin) == NULL)
- return 0;
- /* compute length of the response, and return */
- user_length = MIN(user_length, strlen(buf));
- memcpy(user_buffer, buf, user_length);
- *offset += user_length;
- return user_length;
- }
- /* EXAMPLE STOP */
- int main(int argc, char *argv[])
- {
- struct fusd_file_operations fops = {
- open: do_open_or_close,
- read: do_read,
- close: do_open_or_close };
-
- if (fusd_register("/dev/console-read", "test", "console-read", 0666, NULL, &fops) < 0)
- perror("Unable to register device");
- else {
- printf("/dev/console-read should now exist - calling fusd_run...\n");
- fusd_run();
- }
- return 0;
- }
|