/* * * 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 * * drums3.c: This example shows how to wait for both FUSD and non-FUSD * events at the same time. Instead of using fusd_run, we keep * control of main() by using our own select loop. * * Like the original drums.c, this example creates a bunch of devices * in the /dev/drums directory: /dev/drums/bam, /dev/drums/bum, etc. * However, it also prints a prompt to the console, asking the user if * how loud the drums should be. * */ #include #include #include #include #include #include #include "fusd.h" #define MIN(x, y) ((x) < (y) ? (x) : (y)) static char *drums_strings[] = {"bam", "bum", "beat", "boom", "bang", "crash", NULL}; int volume = 2; /* default volume is 2 */ ssize_t drums_read(struct fusd_file_info *file, char *user_buffer, size_t user_length, loff_t *offset) { int len; char sound[128], *c; /* 1st read returns the sound; 2nd returns EOF */ if (*offset != 0) return 0; if (volume == 1) strcpy(sound, "(you hear nothing)"); else { strcpy(sound, (char *) file->device_info); if (volume >= 3) for (c = sound; *c; c++) *c = toupper(*c); if (volume >= 4) strcat(sound, "!!!!!"); } strcat(sound, "\n"); /* NEVER return more data than the user asked for */ len = MIN(user_length, strlen(sound)); memcpy(user_buffer, sound, len); *offset += len; return len; } int do_open_or_close(struct fusd_file_info *file) { return 0; /* opens and closes always succeed */ } struct fusd_file_operations drums_fops = { open: do_open_or_close, read: drums_read, close: do_open_or_close }; void read_volume(int fd) { char buf[100]; int new_vol = 0, retval; if (fd < 0) goto prompt; retval = read(fd, buf, sizeof(buf)-1); if (retval >= 0) { buf[retval] = '\0'; if (*buf == 'q') { printf("Goodbye...\n"); exit(0); } new_vol = atoi(buf); } if (new_vol >= 1 && new_vol <= 4) { volume = new_vol; printf("Volume changed to %d\n", volume); } else { printf("Invalid volume!\n"); } prompt: printf("\nHow loud would you like the /dev/drums?\n"); printf(" 1 - Inaudible\n"); printf(" 2 - Quiet\n"); printf(" 3 - Loud\n"); printf(" 4 - Permanent ear damage!\n"); printf(" q - Exit program\n"); printf("Your choice? "); fflush(stdout); } int main(int argc, char *argv[]) { int i; char buf[128]; char devname[128]; fd_set fds, tmp; int max; for (i = 0; drums_strings[i] != NULL; i++) { sprintf(buf, "/dev/drums/%s", drums_strings[i]); sprintf(devname, "drum%s", drums_strings[i]); if (fusd_register(buf, "drums", devname, 0666, drums_strings[i], &drums_fops) < 0) fprintf(stderr, "%s register failed: %m\n", drums_strings[i]); } /* print the initial prompt to the user */ read_volume(-1); /* EXAMPLE START drums3.c */ /* initialize the set */ FD_ZERO(&fds); /* add stdin to the set */ FD_SET(STDIN_FILENO, &fds); max = STDIN_FILENO; /* add all FUSD fds to the set */ fusd_fdset_add(&fds, &max); while (1) { tmp = fds; if (select(max+1, &tmp, NULL, NULL, NULL) < 0) perror("selecting"); else { /* if stdin is readable, read the user's response */ if (FD_ISSET(STDIN_FILENO, &tmp)) read_volume(STDIN_FILENO); /* call any FUSD callbacks that have messages waiting */ fusd_dispatch_fdset(&tmp); } } /* EXAMPLE STOP drums3.c */ }