1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2010-2019 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
38 static const int batadv_log_buff_len = BATADV_LOG_BUF_LEN;
39
batadv_log_char_addr(struct batadv_priv_debug_log * debug_log,size_t idx)40 static 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
batadv_emit_log_char(struct batadv_priv_debug_log * debug_log,char c)46 static 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)
batadv_fdebug_log(struct batadv_priv_debug_log * debug_log,const char * fmt,...)60 static 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
batadv_log_open(struct inode * inode,struct file * file)85 static 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
batadv_log_release(struct inode * inode,struct file * file)98 static int batadv_log_release(struct inode *inode, struct file *file)
99 {
100 module_put(THIS_MODULE);
101 return 0;
102 }
103
batadv_log_empty(struct batadv_priv_debug_log * debug_log)104 static bool batadv_log_empty(struct batadv_priv_debug_log *debug_log)
105 {
106 return !(debug_log->log_start - debug_log->log_end);
107 }
108
batadv_log_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)109 static 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
batadv_log_poll(struct file * file,poll_table * wait)164 static __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
177 static 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 };
184
185 /**
186 * batadv_debug_log_setup() - Initialize debug log
187 * @bat_priv: the bat priv with all the soft interface information
188 *
189 * Return: 0 on success or negative error number in case of failure
190 */
batadv_debug_log_setup(struct batadv_priv * bat_priv)191 int batadv_debug_log_setup(struct batadv_priv *bat_priv)
192 {
193 bat_priv->debug_log = kzalloc(sizeof(*bat_priv->debug_log), GFP_ATOMIC);
194 if (!bat_priv->debug_log)
195 return -ENOMEM;
196
197 spin_lock_init(&bat_priv->debug_log->lock);
198 init_waitqueue_head(&bat_priv->debug_log->queue_wait);
199
200 debugfs_create_file("log", 0400, bat_priv->debug_dir, bat_priv,
201 &batadv_log_fops);
202 return 0;
203 }
204
205 /**
206 * batadv_debug_log_cleanup() - Destroy debug log
207 * @bat_priv: the bat priv with all the soft interface information
208 */
batadv_debug_log_cleanup(struct batadv_priv * bat_priv)209 void batadv_debug_log_cleanup(struct batadv_priv *bat_priv)
210 {
211 kfree(bat_priv->debug_log);
212 bat_priv->debug_log = NULL;
213 }
214
215 #endif /* CONFIG_BATMAN_ADV_DEBUGFS */
216
217 /**
218 * batadv_debug_log() - Add debug log entry
219 * @bat_priv: the bat priv with all the soft interface information
220 * @fmt: format string
221 *
222 * Return: 0 on success or negative error number in case of failure
223 */
batadv_debug_log(struct batadv_priv * bat_priv,const char * fmt,...)224 int batadv_debug_log(struct batadv_priv *bat_priv, const char *fmt, ...)
225 {
226 struct va_format vaf;
227 va_list args;
228
229 va_start(args, fmt);
230
231 vaf.fmt = fmt;
232 vaf.va = &args;
233
234 #ifdef CONFIG_BATMAN_ADV_DEBUGFS
235 batadv_fdebug_log(bat_priv->debug_log, "[%10u] %pV",
236 jiffies_to_msecs(jiffies), &vaf);
237 #endif
238
239 trace_batadv_dbg(bat_priv, &vaf);
240
241 va_end(args);
242
243 return 0;
244 }
245