/usr/src/lttng-modules-2.5.1/probes/lttng.c is in lttng-modules-dkms 2.5.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | /*
* lttng.c
*
* LTTng logger ABI
*
* Copyright (C) 2008-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; only
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/module.h>
#include <linux/tracepoint.h>
#include <linux/uaccess.h>
#include <linux/gfp.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include "../wrapper/vmalloc.h"
#include "../lttng-events.h"
#define TP_MODULE_NOAUTOLOAD
#define LTTNG_PACKAGE_BUILD
#define CREATE_TRACE_POINTS
#define TRACE_INCLUDE_PATH ../instrumentation/events/lttng-module
#define TRACE_INCLUDE_FILE lttng
#include "../instrumentation/events/lttng-module/lttng.h"
/* Events written through logger are truncated at 1024 bytes */
#define LTTNG_LOGGER_COUNT_MAX 1024
#define LTTNG_LOGGER_FILE "lttng-logger"
DEFINE_TRACE(lttng_logger);
static struct proc_dir_entry *lttng_logger_dentry;
/**
* lttng_logger_write - write a userspace string into the trace system
* @file: file pointer
* @user_buf: user string
* @count: length to copy
* @ppos: file position
*
* Copy a userspace string into a trace event named "lttng:logger".
* Copies at most @count bytes into the event "msg" dynamic array.
* Truncates the count at LTTNG_LOGGER_COUNT_MAX. Returns the number of
* bytes copied from the source.
* Return -1 on error, with EFAULT errno.
*/
static
ssize_t lttng_logger_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
unsigned int nr_pages = 1, i;
unsigned long uaddr = (unsigned long) user_buf;
struct page *pages[2];
ssize_t written;
int ret;
/* Truncate count */
if (unlikely(count > LTTNG_LOGGER_COUNT_MAX))
count = LTTNG_LOGGER_COUNT_MAX;
/* How many pages are we dealing with ? */
if (unlikely((uaddr & PAGE_MASK) != ((uaddr + count) & PAGE_MASK)))
nr_pages = 2;
/* Pin userspace pages */
ret = get_user_pages_fast(uaddr, nr_pages, 0, pages);
if (unlikely(ret < nr_pages)) {
if (ret > 0) {
BUG_ON(ret != 1);
put_page(pages[0]);
}
written = -EFAULT;
goto end;
}
/* Trace the event */
trace_lttng_logger(user_buf, count);
written = count;
*ppos += written;
for (i = 0; i < nr_pages; i++)
put_page(pages[i]);
end:
return written;
}
static const struct file_operations lttng_logger_operations = {
.write = lttng_logger_write,
};
int __init lttng_logger_init(void)
{
int ret = 0;
wrapper_vmalloc_sync_all();
lttng_logger_dentry = proc_create_data(LTTNG_LOGGER_FILE,
S_IRUGO | S_IWUGO, NULL,
<tng_logger_operations, NULL);
if (!lttng_logger_dentry) {
printk(KERN_ERR "Error creating LTTng logger file\n");
ret = -ENOMEM;
goto error;
}
ret = __lttng_events_init__lttng();
if (ret)
goto error_events;
return ret;
error_events:
remove_proc_entry("lttng-logger", NULL);
error:
return ret;
}
void __exit lttng_logger_exit(void)
{
__lttng_events_exit__lttng();
if (lttng_logger_dentry)
remove_proc_entry("lttng-logger", NULL);
}
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