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- /*
- *
- * 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>
- *
- * hello-world: Simply creates a device called /dev/hello-world, which
- * greets you when you try to get it.
- *
- * $Id: helloworld.c,v 1.11 2003/07/11 22:29:38 cerpa Exp $
- */
- /* EXAMPLE START helloworld.c */
- #include <stdio.h>
- #include <string.h>
- #include <errno.h>
- #include "fusd.h"
- #define GREETING "Hello, world!\n"
- int do_open_or_close(struct fusd_file_info *file)
- {
- return 0; /* attempts to open and close this file always succeed */
- }
- ssize_t do_read(struct fusd_file_info *file, char *user_buffer,
- size_t user_length, loff_t *offset)
- {
- int retval = 0;
-
- /* The first read to the device returns a greeting. The second read
- * returns EOF. */
- if (*offset == 0) {
- if (user_length < strlen(GREETING))
- retval = -EINVAL; /* the user must supply a big enough buffer! */
- else {
- memcpy(user_buffer, GREETING, strlen(GREETING)); /* greet user */
- retval = strlen(GREETING); /* retval = number of bytes returned */
- *offset += retval; /* advance user's file pointer */
- }
- }
-
- return retval;
- }
- 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/hello-world", "test", "hello-world", 0666, NULL, &fops) < 0)
- perror("Unable to register device");
- else {
- printf("/dev/hello-world should now exist - calling fusd_run...\n");
- fusd_run();
- }
- return 0;
- }
- /* EXAMPLE STOP helloworld.c */
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