mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-24 04:34:08 +08:00
9211ddaa78
The ABI has changed to use a remote write approach. Update the example to show the expected use of this new ABI. Also remove debugfs path and use tracefs to ensure example works in more environments. Link: https://lkml.kernel.org/r/20230328235219.203-9-beaub@linux.microsoft.com Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
74 lines
1.4 KiB
C
74 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (c) 2021, Microsoft Corporation.
|
|
*
|
|
* Authors:
|
|
* Beau Belgrave <beaub@linux.microsoft.com>
|
|
*/
|
|
|
|
#include <errno.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/uio.h>
|
|
#include <fcntl.h>
|
|
#include <stdio.h>
|
|
#include <unistd.h>
|
|
#include <linux/user_events.h>
|
|
|
|
const char *data_file = "/sys/kernel/tracing/user_events_data";
|
|
int enabled = 0;
|
|
|
|
static int event_reg(int fd, const char *command, int *write, int *enabled)
|
|
{
|
|
struct user_reg reg = {0};
|
|
|
|
reg.size = sizeof(reg);
|
|
reg.enable_bit = 31;
|
|
reg.enable_size = sizeof(*enabled);
|
|
reg.enable_addr = (__u64)enabled;
|
|
reg.name_args = (__u64)command;
|
|
|
|
if (ioctl(fd, DIAG_IOCSREG, ®) == -1)
|
|
return -1;
|
|
|
|
*write = reg.write_index;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
int data_fd, write;
|
|
struct iovec io[2];
|
|
__u32 count = 0;
|
|
|
|
data_fd = open(data_file, O_RDWR);
|
|
|
|
if (event_reg(data_fd, "test u32 count", &write, &enabled) == -1)
|
|
return errno;
|
|
|
|
/* Setup iovec */
|
|
io[0].iov_base = &write;
|
|
io[0].iov_len = sizeof(write);
|
|
io[1].iov_base = &count;
|
|
io[1].iov_len = sizeof(count);
|
|
ask:
|
|
printf("Press enter to check status...\n");
|
|
getchar();
|
|
|
|
/* Check if anyone is listening */
|
|
if (enabled) {
|
|
/* Yep, trace out our data */
|
|
writev(data_fd, (const struct iovec *)io, 2);
|
|
|
|
/* Increase the count */
|
|
count++;
|
|
|
|
printf("Something was attached, wrote data\n");
|
|
}
|
|
|
|
goto ask;
|
|
|
|
return 0;
|
|
}
|