243da80fc6
an initial release. Primary remaining problem: udev-style kernels don't allow registration of a preexisting class right now. This will need to be fixed semi-immediately. git-svn-id: http://svn.xiph.org/trunk/fusd@12316 0101bb08-14d6-0310-b084-bc0e0c8e3800
118 lines
3.4 KiB
C
118 lines
3.4 KiB
C
/*
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*
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* Copyright (c) 2003 The Regents of the University of California. All
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* rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Neither the name of the University nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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/*
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* FUSD - The Framework for UserSpace Devices - Example program
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*
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* Jeremy Elson <jelson@circlemud.org>
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*
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* drums.c: Example of how to pass data to a callback, inspired by
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* Alessandro Rubini's similar example in his article for Linux
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* Magazine (http://www.linux.it/kerneldocs/devfs/)
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*
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* This example creates a bunch of devices in the /dev/drums
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* directory: /dev/drums/bam, /dev/drums/bum, etc. If you cat one of
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* these devices, it returns a string that's the same as its name.
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*
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* $Id$
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*/
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include "fusd.h"
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#define MIN(x, y) ((x) < (y) ? (x) : (y))
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/* EXAMPLE START drums.c */
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static char *drums_strings[] = {"bam", "bum", "beat", "boom",
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"bang", "crash", NULL};
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int drums_read(struct fusd_file_info *file, char *user_buffer,
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size_t user_length, loff_t *offset)
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{
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int len;
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char sound[128];
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/* file->device_info is what we passed to fusd_register when we
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* registered the device */
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strcpy(sound, (char *) file->device_info);
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strcat(sound, "\n");
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/* 1st read returns the sound; 2nd returns EOF */
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if (*offset != 0)
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return 0;
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/* NEVER return more data than the user asked for */
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len = MIN(user_length, strlen(sound));
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memcpy(user_buffer, sound, len);
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*offset += len;
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return len;
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}
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/* EXAMPLE STOP drums.c */
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int do_open_or_close(struct fusd_file_info *file)
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{
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return 0; /* opens and closes always succeed */
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}
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struct fusd_file_operations drums_fops = {
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open: do_open_or_close,
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read: drums_read,
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close: do_open_or_close
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};
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/* EXAMPLE START drums.c */
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int main(int argc, char *argv[])
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{
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int i;
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char buf[128];
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char devname[128];
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for (i = 0; drums_strings[i] != NULL; i++) {
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sprintf(buf, "/dev/drums/%s", drums_strings[i]);
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sprintf(devname, "drum%s", drums_strings[i]);
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if (fusd_register(buf, "drums", devname, 0666, drums_strings[i], &drums_fops) < 0)
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fprintf(stderr, "%s register failed: %m\n", drums_strings[i]);
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}
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fprintf(stderr, "calling fusd_run...\n");
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fusd_run();
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return 0;
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}
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/* EXAMPLE STOP drums.c */
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