Orange Pi5 kernel

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (c) 2015-2017 Daniel Borkmann */
/* Copyright (c) 2018 Netronome Systems, Inc. */
 
#include <errno.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <linux/magic.h>
#include <sys/fcntl.h>
#include <sys/vfs.h>
 
#include "main.h"
 
#ifndef TRACEFS_MAGIC
# define TRACEFS_MAGIC	0x74726163
#endif
 
#define _textify(x)	#x
#define textify(x)	_textify(x)
 
FILE *trace_pipe_fd;
char *buff;
 
static int validate_tracefs_mnt(const char *mnt, unsigned long magic)
{
<------>struct statfs st_fs;
 
<------>if (statfs(mnt, &st_fs) < 0)
<------><------>return -ENOENT;
<------>if ((unsigned long)st_fs.f_type != magic)
<------><------>return -ENOENT;
 
<------>return 0;
}
 
static bool
find_tracefs_mnt_single(unsigned long magic, char *mnt, const char *mntpt)
{
<------>size_t src_len;
 
<------>if (validate_tracefs_mnt(mntpt, magic))
<------><------>return false;
 
<------>src_len = strlen(mntpt);
<------>if (src_len + 1 >= PATH_MAX) {
<------><------>p_err("tracefs mount point name too long");
<------><------>return false;
<------>}
 
<------>strcpy(mnt, mntpt);
<------>return true;
}
 
static bool get_tracefs_pipe(char *mnt)
{
<------>static const char * const known_mnts[] = {
<------><------>"/sys/kernel/debug/tracing",
<------><------>"/sys/kernel/tracing",
<------><------>"/tracing",
<------><------>"/trace",
<------>};
<------>const char *pipe_name = "/trace_pipe";
<------>const char *fstype = "tracefs";
<------>char type[100], format[32];
<------>const char * const *ptr;
<------>bool found = false;
<------>FILE *fp;
 
<------>for (ptr = known_mnts; ptr < known_mnts + ARRAY_SIZE(known_mnts); ptr++)
<------><------>if (find_tracefs_mnt_single(TRACEFS_MAGIC, mnt, *ptr))
<------><------><------>goto exit_found;
 
<------>fp = fopen("/proc/mounts", "r");
<------>if (!fp)
<------><------>return false;
 
<------>/* Allow room for NULL terminating byte and pipe file name */
<------>snprintf(format, sizeof(format), "%%*s %%%zds %%99s %%*s %%*d %%*d\\n",
<------><------> PATH_MAX - strlen(pipe_name) - 1);
<------>while (fscanf(fp, format, mnt, type) == 2)
<------><------>if (strcmp(type, fstype) == 0) {
<------><------><------>found = true;
<------><------><------>break;
<------><------>}
<------>fclose(fp);
 
<------>/* The string from fscanf() might be truncated, check mnt is valid */
<------>if (found && validate_tracefs_mnt(mnt, TRACEFS_MAGIC))
<------><------>goto exit_found;
 
<------>if (block_mount)
<------><------>return false;
 
<------>p_info("could not find tracefs, attempting to mount it now");
<------>/* Most of the time, tracefs is automatically mounted by debugfs at
<------> * /sys/kernel/debug/tracing when we try to access it. If we could not
<------> * find it, it is likely that debugfs is not mounted. Let's give one
<------> * attempt at mounting just tracefs at /sys/kernel/tracing.
<------> */
<------>strcpy(mnt, known_mnts[1]);
<------>if (mount_tracefs(mnt))
<------><------>return false;
 
exit_found:
<------>strcat(mnt, pipe_name);
<------>return true;
}
 
static void exit_tracelog(int signum)
{
<------>fclose(trace_pipe_fd);
<------>free(buff);
 
<------>if (json_output) {
<------><------>jsonw_end_array(json_wtr);
<------><------>jsonw_destroy(&json_wtr);
<------>}
 
<------>exit(0);
}
 
int do_tracelog(int argc, char **argv)
{
<------>const struct sigaction act = {
<------><------>.sa_handler = exit_tracelog
<------>};
<------>char trace_pipe[PATH_MAX];
<------>size_t buff_len = 0;
 
<------>if (json_output)
<------><------>jsonw_start_array(json_wtr);
 
<------>if (!get_tracefs_pipe(trace_pipe))
<------><------>return -1;
 
<------>trace_pipe_fd = fopen(trace_pipe, "r");
<------>if (!trace_pipe_fd) {
<------><------>p_err("could not open trace pipe: %s", strerror(errno));
<------><------>return -1;
<------>}
 
<------>sigaction(SIGHUP, &act, NULL);
<------>sigaction(SIGINT, &act, NULL);
<------>sigaction(SIGTERM, &act, NULL);
<------>while (1) {
<------><------>ssize_t ret;
 
<------><------>ret = getline(&buff, &buff_len, trace_pipe_fd);
<------><------>if (ret <= 0) {
<------><------><------>p_err("failed to read content from trace pipe: %s",
<------><------><------>      strerror(errno));
<------><------><------>break;
<------><------>}
<------><------>if (json_output)
<------><------><------>jsonw_string(json_wtr, buff);
<------><------>else
<------><------><------>printf("%s", buff);
<------>}
 
<------>fclose(trace_pipe_fd);
<------>free(buff);
<------>return -1;
}