1 /* ----------------------------------------------------------------------- * 2 * 3 * Copyright 2003-2008 H. Peter Anvin - All Rights Reserved 4 * 5 * Permission is hereby granted, free of charge, to any person 6 * obtaining a copy of this software and associated documentation 7 * files (the "Software"), to deal in the Software without 8 * restriction, including without limitation the rights to use, 9 * copy, modify, merge, publish, distribute, sublicense, and/or 10 * sell copies of the Software, and to permit persons to whom 11 * the Software is furnished to do so, subject to the following 12 * conditions: 13 * 14 * The above copyright notice and this permission notice shall 15 * be included in all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 24 * OTHER DEALINGS IN THE SOFTWARE. 25 * 26 * ----------------------------------------------------------------------- */ 27 28 #include <errno.h> 29 #include <com32.h> 30 #include <string.h> 31 #include <unistd.h> 32 #include "file.h" 33 34 /* 35 * opendev.c 36 * 37 * Open a special device 38 */ 39 40 int opendev(const struct input_dev *idev, 41 const struct output_dev *odev, int flags) 42 { 43 int fd; 44 struct file_info *fp; 45 int okflags; 46 int e; 47 48 okflags = (idev ? idev->fileflags : 0) | (odev ? odev->fileflags : 0); 49 50 if (!(flags & 3) || (flags & ~okflags)) { 51 errno = EINVAL; 52 return -1; 53 } 54 55 for (fd = 0, fp = __file_info; fd < NFILES; fd++, fp++) 56 if (!fp->iop && !fp->oop) 57 break; 58 59 if (fd >= NFILES) { 60 errno = EMFILE; 61 return -1; 62 } 63 64 /* The file structure is already zeroed */ 65 fp->iop = &dev_error_r; 66 fp->oop = &dev_error_w; 67 fp->i.datap = fp->i.buf; 68 69 if (idev) { 70 if (idev->open && (e = idev->open(fp))) { 71 errno = e; 72 goto puke; 73 } 74 fp->iop = idev; 75 } 76 77 while (odev) { 78 if (odev->open && (e = odev->open(fp))) { 79 if (e == EAGAIN) { 80 if (odev->fallback) { 81 odev = odev->fallback; 82 continue; 83 } else { 84 e = EIO; 85 } 86 } 87 errno = e; 88 goto puke; 89 } 90 fp->oop = odev; 91 break; 92 } 93 94 return fd; 95 96 puke: 97 close(fd); 98 return -1; 99 } 100