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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 | /* * linux/fs/devices.c * * (C) 1993 Matthias Urlichs -- collected common code and tables. * * Copyright (C) 1991, 1992 Linus Torvalds */ #include <linux/fs.h> #include <linux/major.h> #include <linux/string.h> #include <linux/sched.h> #include <linux/ext_fs.h> #include <linux/stat.h> #include <linux/fcntl.h> #include <linux/errno.h> struct device_struct { const char * name; struct file_operations * fops; }; static struct device_struct chrdevs[MAX_CHRDEV] = { { NULL, NULL }, }; static struct device_struct blkdevs[MAX_BLKDEV] = { { NULL, NULL }, }; struct file_operations * get_blkfops(unsigned int major) { if (major >= MAX_BLKDEV) return NULL; return blkdevs[major].fops; } struct file_operations * get_chrfops(unsigned int major) { if (major >= MAX_CHRDEV) return NULL; return chrdevs[major].fops; } int register_chrdev(unsigned int major, const char * name, struct file_operations *fops) { if (major >= MAX_CHRDEV) return -EINVAL; if (chrdevs[major].fops) return -EBUSY; chrdevs[major].name = name; chrdevs[major].fops = fops; return 0; } int register_blkdev(unsigned int major, const char * name, struct file_operations *fops) { if (major >= MAX_BLKDEV) return -EINVAL; if (blkdevs[major].fops) return -EBUSY; blkdevs[major].name = name; blkdevs[major].fops = fops; return 0; } int unregister_chrdev(unsigned int major, const char * name) { if (major >= MAX_CHRDEV) return -EINVAL; if (!chrdevs[major].fops) return -EINVAL; if (strcmp(chrdevs[major].name, name)) return -EINVAL; chrdevs[major].name = NULL; chrdevs[major].fops = NULL; return 0; } int unregister_blkdev(unsigned int major, const char * name) { if (major >= MAX_BLKDEV) return -EINVAL; if (!blkdevs[major].fops) return -EINVAL; if (strcmp(blkdevs[major].name, name)) return -EINVAL; blkdevs[major].name = NULL; blkdevs[major].fops = NULL; return 0; } /* * Called every time a block special file is opened */ int blkdev_open(struct inode * inode, struct file * filp) { int i; i = MAJOR(inode->i_rdev); if (i >= MAX_BLKDEV || !blkdevs[i].fops) return -ENODEV; filp->f_op = blkdevs[i].fops; if (filp->f_op->open) return filp->f_op->open(inode,filp); return 0; } /* * Dummy default file-operations: the only thing this does * is contain the open that then fills in the correct operations * depending on the special file... */ struct file_operations def_blk_fops = { NULL, /* lseek */ NULL, /* read */ NULL, /* write */ NULL, /* readdir */ NULL, /* select */ NULL, /* ioctl */ NULL, /* mmap */ blkdev_open, /* open */ NULL, /* release */ }; struct inode_operations blkdev_inode_operations = { &def_blk_fops, /* default file operations */ NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* readlink */ NULL, /* follow_link */ NULL, /* bmap */ NULL, /* truncate */ NULL /* permission */ }; /* * Called every time a character special file is opened */ int chrdev_open(struct inode * inode, struct file * filp) { int i; i = MAJOR(inode->i_rdev); if (i >= MAX_CHRDEV || !chrdevs[i].fops) return -ENODEV; filp->f_op = chrdevs[i].fops; if (filp->f_op->open) return filp->f_op->open(inode,filp); return 0; } /* * Dummy default file-operations: the only thing this does * is contain the open that then fills in the correct operations * depending on the special file... */ struct file_operations def_chr_fops = { NULL, /* lseek */ NULL, /* read */ NULL, /* write */ NULL, /* readdir */ NULL, /* select */ NULL, /* ioctl */ NULL, /* mmap */ chrdev_open, /* open */ NULL, /* release */ }; struct inode_operations chrdev_inode_operations = { &def_chr_fops, /* default file operations */ NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* readlink */ NULL, /* follow_link */ NULL, /* bmap */ NULL, /* truncate */ NULL /* permission */ }; |