Bill Pemberton | 0b52b74 | 2012-09-20 16:55:27 -0400 | [diff] [blame] | 1 | /***************************************************************************** |
| 2 | * |
| 3 | * Copyright 1999 Digi International (www.digi.com) |
| 4 | * James Puzzo <jamesp at digi dot com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2, or (at your option) |
| 9 | * any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the |
| 13 | * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR |
| 14 | * PURPOSE. See the GNU General Public License for more details. |
| 15 | * |
| 16 | */ |
| 17 | |
| 18 | /* |
| 19 | * |
| 20 | * Filename: |
| 21 | * |
| 22 | * dgrp_mon_ops.c |
| 23 | * |
| 24 | * Description: |
| 25 | * |
| 26 | * Handle the file operations required for the "monitor" devices. |
| 27 | * Includes those functions required to register the "mon" devices |
| 28 | * in "/proc". |
| 29 | * |
| 30 | * Author: |
| 31 | * |
| 32 | * James A. Puzzo |
| 33 | * |
| 34 | */ |
| 35 | |
| 36 | #include <linux/module.h> |
| 37 | #include <linux/tty.h> |
| 38 | #include <linux/sched.h> |
| 39 | #include <asm/unaligned.h> |
David Howells | 0d01ff2 | 2013-04-11 23:51:01 +0100 | [diff] [blame] | 40 | #include <linux/slab.h> |
Bill Pemberton | 0b52b74 | 2012-09-20 16:55:27 -0400 | [diff] [blame] | 41 | #include <linux/proc_fs.h> |
Geert Uytterhoeven | ee98581 | 2012-09-27 20:38:26 +0200 | [diff] [blame] | 42 | #include <linux/uaccess.h> |
Bill Pemberton | 0b52b74 | 2012-09-20 16:55:27 -0400 | [diff] [blame] | 43 | |
| 44 | #include "dgrp_common.h" |
| 45 | |
| 46 | /* File operation declarations */ |
| 47 | static int dgrp_mon_open(struct inode *, struct file *); |
| 48 | static int dgrp_mon_release(struct inode *, struct file *); |
| 49 | static ssize_t dgrp_mon_read(struct file *, char __user *, size_t, loff_t *); |
| 50 | static long dgrp_mon_ioctl(struct file *file, unsigned int cmd, |
| 51 | unsigned long arg); |
| 52 | |
Al Viro | af064cd | 2013-03-30 01:03:53 -0400 | [diff] [blame] | 53 | const struct file_operations dgrp_mon_ops = { |
Bill Pemberton | 0b52b74 | 2012-09-20 16:55:27 -0400 | [diff] [blame] | 54 | .owner = THIS_MODULE, |
| 55 | .read = dgrp_mon_read, |
| 56 | .unlocked_ioctl = dgrp_mon_ioctl, |
| 57 | .open = dgrp_mon_open, |
| 58 | .release = dgrp_mon_release, |
| 59 | }; |
| 60 | |
Bill Pemberton | 0b52b74 | 2012-09-20 16:55:27 -0400 | [diff] [blame] | 61 | /** |
| 62 | * dgrp_mon_open() -- open /proc/dgrp/ports device for a PortServer |
| 63 | * @inode: struct inode * |
| 64 | * @file: struct file * |
| 65 | * |
| 66 | * Open function to open the /proc/dgrp/ports device for a PortServer. |
| 67 | */ |
| 68 | static int dgrp_mon_open(struct inode *inode, struct file *file) |
| 69 | { |
| 70 | struct nd_struct *nd; |
Bill Pemberton | 0b52b74 | 2012-09-20 16:55:27 -0400 | [diff] [blame] | 71 | struct timeval tv; |
| 72 | uint32_t time; |
| 73 | u8 *buf; |
| 74 | int rtn; |
| 75 | |
| 76 | rtn = try_module_get(THIS_MODULE); |
| 77 | if (!rtn) |
| 78 | return -ENXIO; |
| 79 | |
| 80 | rtn = 0; |
| 81 | |
| 82 | if (!capable(CAP_SYS_ADMIN)) { |
| 83 | rtn = -EPERM; |
| 84 | goto done; |
| 85 | } |
| 86 | |
| 87 | /* |
| 88 | * Make sure that the "private_data" field hasn't already been used. |
| 89 | */ |
| 90 | if (file->private_data) { |
| 91 | rtn = -EINVAL; |
| 92 | goto done; |
| 93 | } |
| 94 | |
| 95 | /* |
| 96 | * Get the node pointer, and fail if it doesn't exist. |
| 97 | */ |
Al Viro | d9dda78 | 2013-03-31 18:16:14 -0400 | [diff] [blame] | 98 | nd = PDE_DATA(inode); |
Bill Pemberton | 0b52b74 | 2012-09-20 16:55:27 -0400 | [diff] [blame] | 99 | if (!nd) { |
| 100 | rtn = -ENXIO; |
| 101 | goto done; |
| 102 | } |
| 103 | |
| 104 | file->private_data = (void *) nd; |
| 105 | |
| 106 | /* |
| 107 | * Allocate the monitor buffer. |
| 108 | */ |
| 109 | |
| 110 | /* |
| 111 | * Grab the MON lock. |
| 112 | */ |
| 113 | down(&nd->nd_mon_semaphore); |
| 114 | |
| 115 | if (nd->nd_mon_buf) { |
| 116 | rtn = -EBUSY; |
| 117 | goto done_up; |
| 118 | } |
| 119 | |
| 120 | nd->nd_mon_buf = kmalloc(MON_MAX, GFP_KERNEL); |
| 121 | |
| 122 | if (!nd->nd_mon_buf) { |
| 123 | rtn = -ENOMEM; |
| 124 | goto done_up; |
| 125 | } |
| 126 | |
| 127 | /* |
| 128 | * Enter an RPDUMP file header into the buffer. |
| 129 | */ |
| 130 | |
| 131 | buf = nd->nd_mon_buf; |
| 132 | |
| 133 | strcpy(buf, RPDUMP_MAGIC); |
| 134 | buf += strlen(buf) + 1; |
| 135 | |
| 136 | do_gettimeofday(&tv); |
| 137 | |
| 138 | /* |
| 139 | * tv.tv_sec might be a 64 bit quantity. Pare |
| 140 | * it down to 32 bits before attempting to encode |
| 141 | * it. |
| 142 | */ |
| 143 | time = (uint32_t) (tv.tv_sec & 0xffffffff); |
| 144 | |
| 145 | put_unaligned_be32(time, buf); |
| 146 | put_unaligned_be16(0, buf + 4); |
| 147 | buf += 6; |
| 148 | |
| 149 | if (nd->nd_tx_module) { |
| 150 | buf[0] = RPDUMP_CLIENT; |
| 151 | put_unaligned_be32(0, buf + 1); |
| 152 | put_unaligned_be16(1, buf + 5); |
| 153 | buf[7] = 0xf0 + nd->nd_tx_module; |
| 154 | buf += 8; |
| 155 | } |
| 156 | |
| 157 | if (nd->nd_rx_module) { |
| 158 | buf[0] = RPDUMP_SERVER; |
| 159 | put_unaligned_be32(0, buf + 1); |
| 160 | put_unaligned_be16(1, buf + 5); |
| 161 | buf[7] = 0xf0 + nd->nd_rx_module; |
| 162 | buf += 8; |
| 163 | } |
| 164 | |
| 165 | nd->nd_mon_out = 0; |
| 166 | nd->nd_mon_in = buf - nd->nd_mon_buf; |
| 167 | nd->nd_mon_lbolt = jiffies; |
| 168 | |
| 169 | done_up: |
| 170 | up(&nd->nd_mon_semaphore); |
| 171 | |
| 172 | done: |
| 173 | if (rtn) |
| 174 | module_put(THIS_MODULE); |
| 175 | return rtn; |
| 176 | } |
| 177 | |
| 178 | |
| 179 | /** |
| 180 | * dgrp_mon_release() - Close the MON device for a particular PortServer |
| 181 | * @inode: struct inode * |
| 182 | * @file: struct file * |
| 183 | */ |
| 184 | static int dgrp_mon_release(struct inode *inode, struct file *file) |
| 185 | { |
| 186 | struct nd_struct *nd; |
| 187 | |
| 188 | /* |
| 189 | * Get the node pointer, and quit if it doesn't exist. |
| 190 | */ |
| 191 | nd = (struct nd_struct *)(file->private_data); |
| 192 | if (!nd) |
| 193 | goto done; |
| 194 | |
| 195 | /* |
| 196 | * Free the monitor buffer. |
| 197 | */ |
| 198 | |
| 199 | down(&nd->nd_mon_semaphore); |
| 200 | |
| 201 | kfree(nd->nd_mon_buf); |
| 202 | nd->nd_mon_buf = NULL; |
| 203 | nd->nd_mon_out = nd->nd_mon_in; |
| 204 | |
| 205 | /* |
| 206 | * Wakeup any thread waiting for buffer space. |
| 207 | */ |
| 208 | |
| 209 | if (nd->nd_mon_flag & MON_WAIT_SPACE) { |
| 210 | nd->nd_mon_flag &= ~MON_WAIT_SPACE; |
| 211 | wake_up_interruptible(&nd->nd_mon_wqueue); |
| 212 | } |
| 213 | |
| 214 | up(&nd->nd_mon_semaphore); |
| 215 | |
| 216 | /* |
| 217 | * Make sure there is no thread in the middle of writing a packet. |
| 218 | */ |
| 219 | down(&nd->nd_net_semaphore); |
| 220 | up(&nd->nd_net_semaphore); |
| 221 | |
| 222 | done: |
| 223 | module_put(THIS_MODULE); |
| 224 | file->private_data = NULL; |
| 225 | return 0; |
| 226 | } |
| 227 | |
| 228 | /** |
| 229 | * dgrp_mon_read() -- Copy data from the monitoring buffer to the user |
| 230 | */ |
| 231 | static ssize_t dgrp_mon_read(struct file *file, char __user *buf, size_t count, |
| 232 | loff_t *ppos) |
| 233 | { |
| 234 | struct nd_struct *nd; |
| 235 | int r; |
| 236 | int offset = 0; |
| 237 | int res = 0; |
| 238 | ssize_t rtn; |
| 239 | |
| 240 | /* |
| 241 | * Get the node pointer, and quit if it doesn't exist. |
| 242 | */ |
| 243 | nd = (struct nd_struct *)(file->private_data); |
| 244 | if (!nd) |
| 245 | return -ENXIO; |
| 246 | |
| 247 | /* |
| 248 | * Wait for some data to appear in the buffer. |
| 249 | */ |
| 250 | |
| 251 | down(&nd->nd_mon_semaphore); |
| 252 | |
| 253 | for (;;) { |
| 254 | res = (nd->nd_mon_in - nd->nd_mon_out) & MON_MASK; |
| 255 | |
| 256 | if (res) |
| 257 | break; |
| 258 | |
| 259 | nd->nd_mon_flag |= MON_WAIT_DATA; |
| 260 | |
| 261 | up(&nd->nd_mon_semaphore); |
| 262 | |
| 263 | /* |
| 264 | * Go to sleep waiting until the condition becomes true. |
| 265 | */ |
| 266 | rtn = wait_event_interruptible(nd->nd_mon_wqueue, |
| 267 | ((nd->nd_mon_flag & MON_WAIT_DATA) == 0)); |
| 268 | |
| 269 | if (rtn) |
| 270 | return rtn; |
| 271 | |
| 272 | down(&nd->nd_mon_semaphore); |
| 273 | } |
| 274 | |
| 275 | /* |
| 276 | * Read whatever is there. |
| 277 | */ |
| 278 | |
| 279 | if (res > count) |
| 280 | res = count; |
| 281 | |
| 282 | r = MON_MAX - nd->nd_mon_out; |
| 283 | |
| 284 | if (r <= res) { |
| 285 | rtn = copy_to_user((void __user *)buf, |
| 286 | nd->nd_mon_buf + nd->nd_mon_out, r); |
| 287 | if (rtn) { |
| 288 | up(&nd->nd_mon_semaphore); |
| 289 | return -EFAULT; |
| 290 | } |
| 291 | |
| 292 | nd->nd_mon_out = 0; |
| 293 | res -= r; |
| 294 | offset = r; |
| 295 | } |
| 296 | |
| 297 | rtn = copy_to_user((void __user *) buf + offset, |
| 298 | nd->nd_mon_buf + nd->nd_mon_out, res); |
| 299 | if (rtn) { |
| 300 | up(&nd->nd_mon_semaphore); |
| 301 | return -EFAULT; |
| 302 | } |
| 303 | |
| 304 | nd->nd_mon_out += res; |
| 305 | |
| 306 | *ppos += res; |
| 307 | |
| 308 | up(&nd->nd_mon_semaphore); |
| 309 | |
| 310 | /* |
| 311 | * Wakeup any thread waiting for buffer space. |
| 312 | */ |
| 313 | |
| 314 | if (nd->nd_mon_flag & MON_WAIT_SPACE) { |
| 315 | nd->nd_mon_flag &= ~MON_WAIT_SPACE; |
| 316 | wake_up_interruptible(&nd->nd_mon_wqueue); |
| 317 | } |
| 318 | |
| 319 | return res; |
| 320 | } |
| 321 | |
| 322 | /* ioctl is not valid on monitor device */ |
| 323 | static long dgrp_mon_ioctl(struct file *file, unsigned int cmd, |
| 324 | unsigned long arg) |
| 325 | { |
| 326 | return -EINVAL; |
| 327 | } |