Commit | Line | Data |
---|---|---|
0c956676 MD |
1 | /* |
2 | * lttng.c | |
3 | * | |
4 | * LTTng logger ABI | |
5 | * | |
6 | * Copyright (C) 2008-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; only | |
11 | * version 2.1 of the License. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | */ | |
22 | ||
23 | #include <linux/module.h> | |
24 | #include <linux/tracepoint.h> | |
25 | #include <linux/uaccess.h> | |
26 | #include <linux/gfp.h> | |
27 | #include <linux/fs.h> | |
28 | #include <linux/proc_fs.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/mm.h> | |
4d328377 | 31 | #include <linux/miscdevice.h> |
156a3977 MD |
32 | #include <wrapper/vmalloc.h> |
33 | #include <lttng-events.h> | |
0c956676 MD |
34 | |
35 | #define TP_MODULE_NOAUTOLOAD | |
36 | #define LTTNG_PACKAGE_BUILD | |
37 | #define CREATE_TRACE_POINTS | |
c075712b | 38 | #define TRACE_INCLUDE_PATH instrumentation/events/lttng-module |
0c956676 | 39 | #define TRACE_INCLUDE_FILE lttng |
3bc29f0a | 40 | #define LTTNG_INSTRUMENTATION |
0c956676 | 41 | |
156a3977 | 42 | #include <instrumentation/events/lttng-module/lttng.h> |
0c956676 MD |
43 | |
44 | /* Events written through logger are truncated at 1024 bytes */ | |
45 | #define LTTNG_LOGGER_COUNT_MAX 1024 | |
46 | #define LTTNG_LOGGER_FILE "lttng-logger" | |
47 | ||
20591cf7 MD |
48 | DEFINE_TRACE(lttng_logger); |
49 | ||
0c956676 MD |
50 | static struct proc_dir_entry *lttng_logger_dentry; |
51 | ||
52 | /** | |
53 | * lttng_logger_write - write a userspace string into the trace system | |
54 | * @file: file pointer | |
55 | * @user_buf: user string | |
56 | * @count: length to copy | |
57 | * @ppos: file position | |
58 | * | |
59 | * Copy a userspace string into a trace event named "lttng:logger". | |
60 | * Copies at most @count bytes into the event "msg" dynamic array. | |
61 | * Truncates the count at LTTNG_LOGGER_COUNT_MAX. Returns the number of | |
62 | * bytes copied from the source. | |
63 | * Return -1 on error, with EFAULT errno. | |
64 | */ | |
65 | static | |
66 | ssize_t lttng_logger_write(struct file *file, const char __user *user_buf, | |
67 | size_t count, loff_t *ppos) | |
68 | { | |
467f3a48 | 69 | int nr_pages = 1, i; |
0c956676 MD |
70 | unsigned long uaddr = (unsigned long) user_buf; |
71 | struct page *pages[2]; | |
72 | ssize_t written; | |
73 | int ret; | |
74 | ||
75 | /* Truncate count */ | |
76 | if (unlikely(count > LTTNG_LOGGER_COUNT_MAX)) | |
77 | count = LTTNG_LOGGER_COUNT_MAX; | |
78 | ||
79 | /* How many pages are we dealing with ? */ | |
80 | if (unlikely((uaddr & PAGE_MASK) != ((uaddr + count) & PAGE_MASK))) | |
81 | nr_pages = 2; | |
82 | ||
83 | /* Pin userspace pages */ | |
84 | ret = get_user_pages_fast(uaddr, nr_pages, 0, pages); | |
85 | if (unlikely(ret < nr_pages)) { | |
86 | if (ret > 0) { | |
87 | BUG_ON(ret != 1); | |
88 | put_page(pages[0]); | |
89 | } | |
90 | written = -EFAULT; | |
91 | goto end; | |
92 | } | |
93 | ||
94 | /* Trace the event */ | |
95 | trace_lttng_logger(user_buf, count); | |
96 | written = count; | |
97 | *ppos += written; | |
98 | ||
99 | for (i = 0; i < nr_pages; i++) | |
100 | put_page(pages[i]); | |
101 | end: | |
102 | return written; | |
103 | } | |
104 | ||
105 | static const struct file_operations lttng_logger_operations = { | |
106 | .write = lttng_logger_write, | |
107 | }; | |
108 | ||
4d328377 SG |
109 | static struct miscdevice logger_dev = { |
110 | .minor = MISC_DYNAMIC_MINOR, | |
111 | .name = "lttng-logger", | |
112 | .mode = 0666, | |
113 | .fops = <tng_logger_operations | |
114 | }; | |
115 | ||
0c956676 MD |
116 | int __init lttng_logger_init(void) |
117 | { | |
118 | int ret = 0; | |
119 | ||
120 | wrapper_vmalloc_sync_all(); | |
4d328377 SG |
121 | |
122 | /* /dev/lttng-logger */ | |
123 | ret = misc_register(&logger_dev); | |
124 | if (ret) { | |
125 | printk(KERN_ERR "Error creating LTTng logger device\n"); | |
126 | goto error; | |
127 | } | |
128 | ||
129 | /* /proc/lttng-logger */ | |
0c956676 MD |
130 | lttng_logger_dentry = proc_create_data(LTTNG_LOGGER_FILE, |
131 | S_IRUGO | S_IWUGO, NULL, | |
132 | <tng_logger_operations, NULL); | |
133 | if (!lttng_logger_dentry) { | |
4d328377 | 134 | printk(KERN_ERR "Error creating LTTng logger proc file\n"); |
0c956676 | 135 | ret = -ENOMEM; |
4d328377 | 136 | goto error_proc; |
0c956676 | 137 | } |
4d328377 SG |
138 | |
139 | /* Init */ | |
0c956676 MD |
140 | ret = __lttng_events_init__lttng(); |
141 | if (ret) | |
142 | goto error_events; | |
143 | return ret; | |
144 | ||
145 | error_events: | |
146 | remove_proc_entry("lttng-logger", NULL); | |
4d328377 SG |
147 | error_proc: |
148 | misc_deregister(&logger_dev); | |
0c956676 MD |
149 | error: |
150 | return ret; | |
151 | } | |
152 | ||
32fe46fb | 153 | void lttng_logger_exit(void) |
0c956676 MD |
154 | { |
155 | __lttng_events_exit__lttng(); | |
156 | if (lttng_logger_dentry) | |
157 | remove_proc_entry("lttng-logger", NULL); | |
4d328377 | 158 | misc_deregister(&logger_dev); |
0c956676 | 159 | } |