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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2013 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "tracefs.h"
#include "trace-local.h"
static void write_file(const char *name, char *val)
{
char *path;
int fd;
ssize_t n;
path = tracefs_get_tracing_file(name);
fd = open(path, O_WRONLY);
if (fd < 0)
die("writing %s", path);
n = write(fd, val, strlen(val));
if (n < 0)
die("failed to write to %s\n", path);
tracefs_put_tracing_file(path);
close(fd);
}
void trace_snapshot (int argc, char **argv)
{
const char *buffer = NULL;
const char *file = "snapshot";
struct stat st;
char *name;
char cpu_path[128];
int take_snap = 0;
int reset_snap = 0;
int free_snap = 0;
int cpu = -1;
int ret;
int c;
if (argc < 2)
usage(argv);
if (strcmp(argv[1], "snapshot") != 0)
usage(argv);
while ((c = getopt(argc-1, argv+1, "srfB:c:")) >= 0) {
switch (c) {
case 'h':
usage(argv);
break;
case 's':
take_snap = 1;
if (free_snap)
die("can't take snapshot and free it at the same time");
break;
case 'f':
free_snap = 1;
if (take_snap)
die("can't take snapshot and free it at the same time");
break;
case 'r':
reset_snap = 1;
break;
case 'B':
if (buffer)
die("Can only do one buffer at a time");
buffer = optarg;
break;
case 'c':
if (cpu >= 0)
die("Can only do one CPU (or all) at a time");
cpu = atoi(optarg);
break;
default:
usage(argv);
}
}
if (cpu >= 0) {
snprintf(cpu_path, 128, "per_cpu/cpu%d/%s", cpu, file);
file = cpu_path;
}
name = tracefs_get_tracing_file(file);
ret = stat(name, &st);
if (ret < 0)
die("Snapshot feature is not supported by this kernel");
tracefs_put_tracing_file(name);
if (!reset_snap && !take_snap && !free_snap) {
show_file(file);
exit(0);
}
if (reset_snap)
write_file(file, "2");
if (free_snap)
write_file(file, "0");
if (take_snap)
write_file(file, "1");
}
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