1// SPDX-License-Identifier: GPL-2.0 2/* Copyright (C) 2010-2020 B.A.T.M.A.N. contributors: 3 * 4 * Marek Lindner 5 */ 6 7#include "log.h" 8#include "main.h" 9 10#include <linux/compiler.h> 11#include <linux/debugfs.h> 12#include <linux/errno.h> 13#include <linux/eventpoll.h> 14#include <linux/export.h> 15#include <linux/fcntl.h> 16#include <linux/fs.h> 17#include <linux/gfp.h> 18#include <linux/jiffies.h> 19#include <linux/kernel.h> 20#include <linux/module.h> 21#include <linux/poll.h> 22#include <linux/sched.h> /* for linux/wait.h */ 23#include <linux/slab.h> 24#include <linux/spinlock.h> 25#include <linux/stddef.h> 26#include <linux/types.h> 27#include <linux/uaccess.h> 28#include <linux/wait.h> 29#include <stdarg.h> 30 31#include "debugfs.h" 32#include "trace.h" 33 34#ifdef CONFIG_BATMAN_ADV_DEBUGFS 35 36#define BATADV_LOG_BUFF_MASK (batadv_log_buff_len - 1) 37 38static const int batadv_log_buff_len = BATADV_LOG_BUF_LEN; 39 40static char *batadv_log_char_addr(struct batadv_priv_debug_log *debug_log, 41 size_t idx) 42{ 43 return &debug_log->log_buff[idx & BATADV_LOG_BUFF_MASK]; 44} 45 46static void batadv_emit_log_char(struct batadv_priv_debug_log *debug_log, 47 char c) 48{ 49 char *char_addr; 50 51 char_addr = batadv_log_char_addr(debug_log, debug_log->log_end); 52 *char_addr = c; 53 debug_log->log_end++; 54 55 if (debug_log->log_end - debug_log->log_start > batadv_log_buff_len) 56 debug_log->log_start = debug_log->log_end - batadv_log_buff_len; 57} 58 59__printf(2, 3) 60static int batadv_fdebug_log(struct batadv_priv_debug_log *debug_log, 61 const char *fmt, ...) 62{ 63 va_list args; 64 static char debug_log_buf[256]; 65 char *p; 66 67 if (!debug_log) 68 return 0; 69 70 spin_lock_bh(&debug_log->lock); 71 va_start(args, fmt); 72 vscnprintf(debug_log_buf, sizeof(debug_log_buf), fmt, args); 73 va_end(args); 74 75 for (p = debug_log_buf; *p != 0; p++) 76 batadv_emit_log_char(debug_log, *p); 77 78 spin_unlock_bh(&debug_log->lock); 79 80 wake_up(&debug_log->queue_wait); 81 82 return 0; 83} 84 85static int batadv_log_open(struct inode *inode, struct file *file) 86{ 87 if (!try_module_get(THIS_MODULE)) 88 return -EBUSY; 89 90 batadv_debugfs_deprecated(file, 91 "Use tracepoint batadv:batadv_dbg instead\n"); 92 93 stream_open(inode, file); 94 file->private_data = inode->i_private; 95 return 0; 96} 97 98static int batadv_log_release(struct inode *inode, struct file *file) 99{ 100 module_put(THIS_MODULE); 101 return 0; 102} 103 104static bool batadv_log_empty(struct batadv_priv_debug_log *debug_log) 105{ 106 return !(debug_log->log_start - debug_log->log_end); 107} 108 109static ssize_t batadv_log_read(struct file *file, char __user *buf, 110 size_t count, loff_t *ppos) 111{ 112 struct batadv_priv *bat_priv = file->private_data; 113 struct batadv_priv_debug_log *debug_log = bat_priv->debug_log; 114 int error, i = 0; 115 char *char_addr; 116 char c; 117 118 if ((file->f_flags & O_NONBLOCK) && batadv_log_empty(debug_log)) 119 return -EAGAIN; 120 121 if (!buf) 122 return -EINVAL; 123 124 if (count == 0) 125 return 0; 126 127 if (!access_ok(buf, count)) 128 return -EFAULT; 129 130 error = wait_event_interruptible(debug_log->queue_wait, 131 (!batadv_log_empty(debug_log))); 132 133 if (error) 134 return error; 135 136 spin_lock_bh(&debug_log->lock); 137 138 while ((!error) && (i < count) && 139 (debug_log->log_start != debug_log->log_end)) { 140 char_addr = batadv_log_char_addr(debug_log, 141 debug_log->log_start); 142 c = *char_addr; 143 144 debug_log->log_start++; 145 146 spin_unlock_bh(&debug_log->lock); 147 148 error = __put_user(c, buf); 149 150 spin_lock_bh(&debug_log->lock); 151 152 buf++; 153 i++; 154 } 155 156 spin_unlock_bh(&debug_log->lock); 157 158 if (!error) 159 return i; 160 161 return error; 162} 163 164static __poll_t batadv_log_poll(struct file *file, poll_table *wait) 165{ 166 struct batadv_priv *bat_priv = file->private_data; 167 struct batadv_priv_debug_log *debug_log = bat_priv->debug_log; 168 169 poll_wait(file, &debug_log->queue_wait, wait); 170 171 if (!batadv_log_empty(debug_log)) 172 return EPOLLIN | EPOLLRDNORM; 173 174 return 0; 175} 176 177static const struct file_operations batadv_log_fops = { 178 .open = batadv_log_open, 179 .release = batadv_log_release, 180 .read = batadv_log_read, 181 .poll = batadv_log_poll, 182 .llseek = no_llseek, 183 .owner = THIS_MODULE, 184}; 185 186/** 187 * batadv_debug_log_setup() - Initialize debug log 188 * @bat_priv: the bat priv with all the soft interface information 189 * 190 * Return: 0 on success or negative error number in case of failure 191 */ 192int batadv_debug_log_setup(struct batadv_priv *bat_priv) 193{ 194 bat_priv->debug_log = kzalloc(sizeof(*bat_priv->debug_log), GFP_ATOMIC); 195 if (!bat_priv->debug_log) 196 return -ENOMEM; 197 198 spin_lock_init(&bat_priv->debug_log->lock); 199 init_waitqueue_head(&bat_priv->debug_log->queue_wait); 200 201 debugfs_create_file("log", 0400, bat_priv->debug_dir, bat_priv, 202 &batadv_log_fops); 203 return 0; 204} 205 206/** 207 * batadv_debug_log_cleanup() - Destroy debug log 208 * @bat_priv: the bat priv with all the soft interface information 209 */ 210void batadv_debug_log_cleanup(struct batadv_priv *bat_priv) 211{ 212 kfree(bat_priv->debug_log); 213 bat_priv->debug_log = NULL; 214} 215 216#endif /* CONFIG_BATMAN_ADV_DEBUGFS */ 217 218/** 219 * batadv_debug_log() - Add debug log entry 220 * @bat_priv: the bat priv with all the soft interface information 221 * @fmt: format string 222 * 223 * Return: 0 on success or negative error number in case of failure 224 */ 225int batadv_debug_log(struct batadv_priv *bat_priv, const char *fmt, ...) 226{ 227 struct va_format vaf; 228 va_list args; 229 230 va_start(args, fmt); 231 232 vaf.fmt = fmt; 233 vaf.va = &args; 234 235#ifdef CONFIG_BATMAN_ADV_DEBUGFS 236 batadv_fdebug_log(bat_priv->debug_log, "[%10u] %pV", 237 jiffies_to_msecs(jiffies), &vaf); 238#endif 239 240 trace_batadv_dbg(bat_priv, &vaf); 241 242 va_end(args); 243 244 return 0; 245} 246