[mirror_ubuntu-jammy-kernel.git] / tools / perf / builtin-ftrace.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * builtin-ftrace.c
 *
 * Copyright (c) 2013  LG Electronics,  Namhyung Kim <namhyung@kernel.org>
 */

#include "builtin.h"

#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <fcntl.h>
#include <poll.h>
#include <linux/capability.h>
#include <linux/string.h>

#include "debug.h"
#include <subcmd/pager.h>
#include <subcmd/parse-options.h>
#include <api/fs/tracing_path.h>
#include "evlist.h"
#include "target.h"
#include "cpumap.h"
#include "thread_map.h"
#include "util/cap.h"
#include "util/config.h"

#define DEFAULT_TRACER  "function_graph"

struct perf_ftrace {
	struct evlist		*evlist;
	struct target		target;
	const char		*tracer;
	struct list_head	filters;
	struct list_head	notrace;
	struct list_head	graph_funcs;
	struct list_head	nograph_funcs;
	int			graph_depth;
};

struct filter_entry {
	struct list_head	list;
	char			name[];
};

static bool done;

static void sig_handler(int sig __maybe_unused)
{
	done = true;
}

/*
 * perf_evlist__prepare_workload will send a SIGUSR1 if the fork fails, since
 * we asked by setting its exec_error to the function below,
 * ftrace__workload_exec_failed_signal.
 *
 * XXX We need to handle this more appropriately, emitting an error, etc.
 */
static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,
						siginfo_t *info __maybe_unused,
						void *ucontext __maybe_unused)
{
	/* workload_exec_errno = info->si_value.sival_int; */
	done = true;
}

static int __write_tracing_file(const char *name, const char *val, bool append)
{
	char *file;
	int fd, ret = -1;
	ssize_t size = strlen(val);
	int flags = O_WRONLY;
	char errbuf[512];
	char *val_copy;

	file = get_tracing_file(name);
	if (!file) {
		pr_debug("cannot get tracing file: %s\n", name);
		return -1;
	}

	if (append)
		flags |= O_APPEND;
	else
		flags |= O_TRUNC;

	fd = open(file, flags);
	if (fd < 0) {
		pr_debug("cannot open tracing file: %s: %s\n",
			 name, str_error_r(errno, errbuf, sizeof(errbuf)));
		goto out;
	}

	/*
	 * Copy the original value and append a '\n'. Without this,
	 * the kernel can hide possible errors.
	 */
	val_copy = strdup(val);
	if (!val_copy)
		goto out_close;
	val_copy[size] = '\n';

	if (write(fd, val_copy, size + 1) == size + 1)
		ret = 0;
	else
		pr_debug("write '%s' to tracing/%s failed: %s\n",
			 val, name, str_error_r(errno, errbuf, sizeof(errbuf)));

	free(val_copy);
out_close:
	close(fd);
out:
	put_tracing_file(file);
	return ret;
}

static int write_tracing_file(const char *name, const char *val)
{
	return __write_tracing_file(name, val, false);
}

static int append_tracing_file(const char *name, const char *val)
{
	return __write_tracing_file(name, val, true);
}

static int reset_tracing_cpu(void);
static void reset_tracing_filters(void);

static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
{
	if (write_tracing_file("tracing_on", "0") < 0)
		return -1;

	if (write_tracing_file("current_tracer", "nop") < 0)
		return -1;

	if (write_tracing_file("set_ftrace_pid", " ") < 0)
		return -1;

	if (reset_tracing_cpu() < 0)
		return -1;

	if (write_tracing_file("max_graph_depth", "0") < 0)
		return -1;

	reset_tracing_filters();
	return 0;
}

static int set_tracing_pid(struct perf_ftrace *ftrace)
{
	int i;
	char buf[16];

	if (target__has_cpu(&ftrace->target))
		return 0;

	for (i = 0; i < perf_thread_map__nr(ftrace->evlist->core.threads); i++) {
		scnprintf(buf, sizeof(buf), "%d",
			  ftrace->evlist->core.threads->map[i]);
		if (append_tracing_file("set_ftrace_pid", buf) < 0)
			return -1;
	}
	return 0;
}

static int set_tracing_cpumask(struct perf_cpu_map *cpumap)
{
	char *cpumask;
	size_t mask_size;
	int ret;
	int last_cpu;

	last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);
	mask_size = last_cpu / 4 + 2; /* one more byte for EOS */
	mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */

	cpumask = malloc(mask_size);
	if (cpumask == NULL) {
		pr_debug("failed to allocate cpu mask\n");
		return -1;
	}

	cpu_map__snprint_mask(cpumap, cpumask, mask_size);

	ret = write_tracing_file("tracing_cpumask", cpumask);

	free(cpumask);
	return ret;
}

static int set_tracing_cpu(struct perf_ftrace *ftrace)
{
	struct perf_cpu_map *cpumap = ftrace->evlist->core.cpus;

	if (!target__has_cpu(&ftrace->target))
		return 0;

	return set_tracing_cpumask(cpumap);
}

static int reset_tracing_cpu(void)
{
	struct perf_cpu_map *cpumap = perf_cpu_map__new(NULL);
	int ret;

	ret = set_tracing_cpumask(cpumap);
	perf_cpu_map__put(cpumap);
	return ret;
}

static int __set_tracing_filter(const char *filter_file, struct list_head *funcs)
{
	struct filter_entry *pos;

	list_for_each_entry(pos, funcs, list) {
		if (append_tracing_file(filter_file, pos->name) < 0)
			return -1;
	}

	return 0;
}

static int set_tracing_filters(struct perf_ftrace *ftrace)
{
	int ret;

	ret = __set_tracing_filter("set_ftrace_filter", &ftrace->filters);
	if (ret < 0)
		return ret;

	ret = __set_tracing_filter("set_ftrace_notrace", &ftrace->notrace);
	if (ret < 0)
		return ret;

	ret = __set_tracing_filter("set_graph_function", &ftrace->graph_funcs);
	if (ret < 0)
		return ret;

	/* old kernels do not have this filter */
	__set_tracing_filter("set_graph_notrace", &ftrace->nograph_funcs);

	return ret;
}

static void reset_tracing_filters(void)
{
	write_tracing_file("set_ftrace_filter", " ");
	write_tracing_file("set_ftrace_notrace", " ");
	write_tracing_file("set_graph_function", " ");
	write_tracing_file("set_graph_notrace", " ");
}

static int set_tracing_depth(struct perf_ftrace *ftrace)
{
	char buf[16];

	if (ftrace->graph_depth == 0)
		return 0;

	if (ftrace->graph_depth < 0) {
		pr_err("invalid graph depth: %d\n", ftrace->graph_depth);
		return -1;
	}

	snprintf(buf, sizeof(buf), "%d", ftrace->graph_depth);

	if (write_tracing_file("max_graph_depth", buf) < 0)
		return -1;

	return 0;
}

static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
{
	char *trace_file;
	int trace_fd;
	char buf[4096];
	struct pollfd pollfd = {
		.events = POLLIN,
	};

	if (!perf_cap__capable(CAP_SYS_ADMIN)) {
		pr_err("ftrace only works for %s!\n",
#ifdef HAVE_LIBCAP_SUPPORT
		"users with the SYS_ADMIN capability"
#else
		"root"
#endif
		);
		return -1;
	}

	signal(SIGINT, sig_handler);
	signal(SIGUSR1, sig_handler);
	signal(SIGCHLD, sig_handler);
	signal(SIGPIPE, sig_handler);

	if (reset_tracing_files(ftrace) < 0) {
		pr_err("failed to reset ftrace\n");
		goto out;
	}

	/* reset ftrace buffer */
	if (write_tracing_file("trace", "0") < 0)
		goto out;

	if (argc && perf_evlist__prepare_workload(ftrace->evlist,
				&ftrace->target, argv, false,
				ftrace__workload_exec_failed_signal) < 0) {
		goto out;
	}

	if (set_tracing_pid(ftrace) < 0) {
		pr_err("failed to set ftrace pid\n");
		goto out_reset;
	}

	if (set_tracing_cpu(ftrace) < 0) {
		pr_err("failed to set tracing cpumask\n");
		goto out_reset;
	}

	if (set_tracing_filters(ftrace) < 0) {
		pr_err("failed to set tracing filters\n");
		goto out_reset;
	}

	if (set_tracing_depth(ftrace) < 0) {
		pr_err("failed to set graph depth\n");
		goto out_reset;
	}

	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
		pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
		goto out_reset;
	}

	setup_pager();

	trace_file = get_tracing_file("trace_pipe");
	if (!trace_file) {
		pr_err("failed to open trace_pipe\n");
		goto out_reset;
	}

	trace_fd = open(trace_file, O_RDONLY);

	put_tracing_file(trace_file);

	if (trace_fd < 0) {
		pr_err("failed to open trace_pipe\n");
		goto out_reset;
	}

	fcntl(trace_fd, F_SETFL, O_NONBLOCK);
	pollfd.fd = trace_fd;

	if (write_tracing_file("tracing_on", "1") < 0) {
		pr_err("can't enable tracing\n");
		goto out_close_fd;
	}

	perf_evlist__start_workload(ftrace->evlist);

	while (!done) {
		if (poll(&pollfd, 1, -1) < 0)
			break;

		if (pollfd.revents & POLLIN) {
			int n = read(trace_fd, buf, sizeof(buf));
			if (n < 0)
				break;
			if (fwrite(buf, n, 1, stdout) != 1)
				break;
		}
	}

	write_tracing_file("tracing_on", "0");

	/* read remaining buffer contents */
	while (true) {
		int n = read(trace_fd, buf, sizeof(buf));
		if (n <= 0)
			break;
		if (fwrite(buf, n, 1, stdout) != 1)
			break;
	}

out_close_fd:
	close(trace_fd);
out_reset:
	reset_tracing_files(ftrace);
out:
	return done ? 0 : -1;
}

static int perf_ftrace_config(const char *var, const char *value, void *cb)
{
	struct perf_ftrace *ftrace = cb;

	if (!strstarts(var, "ftrace."))
		return 0;

	if (strcmp(var, "ftrace.tracer"))
		return -1;

	if (!strcmp(value, "function_graph") ||
	    !strcmp(value, "function")) {
		ftrace->tracer = value;
		return 0;
	}

	pr_err("Please select \"function_graph\" (default) or \"function\"\n");
	return -1;
}

static int parse_filter_func(const struct option *opt, const char *str,
			     int unset __maybe_unused)
{
	struct list_head *head = opt->value;
	struct filter_entry *entry;

	entry = malloc(sizeof(*entry) + strlen(str) + 1);
	if (entry == NULL)
		return -ENOMEM;

	strcpy(entry->name, str);
	list_add_tail(&entry->list, head);

	return 0;
}

static void delete_filter_func(struct list_head *head)
{
	struct filter_entry *pos, *tmp;

	list_for_each_entry_safe(pos, tmp, head, list) {
		list_del_init(&pos->list);
		free(pos);
	}
}

int cmd_ftrace(int argc, const char **argv)
{
	int ret;
	struct perf_ftrace ftrace = {
		.tracer = DEFAULT_TRACER,
		.target = { .uid = UINT_MAX, },
	};
	const char * const ftrace_usage[] = {
		"perf ftrace [<options>] [<command>]",
		"perf ftrace [<options>] -- <command> [<options>]",
		NULL
	};
	const struct option ftrace_options[] = {
	OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
		   "tracer to use: function_graph(default) or function"),
	OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
		   "trace on existing process id"),
	OPT_INCR('v', "verbose", &verbose,
		 "be more verbose"),
	OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
		    "system-wide collection from all CPUs"),
	OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
		    "list of cpus to monitor"),
	OPT_CALLBACK('T', "trace-funcs", &ftrace.filters, "func",
		     "trace given functions only", parse_filter_func),
	OPT_CALLBACK('N', "notrace-funcs", &ftrace.notrace, "func",
		     "do not trace given functions", parse_filter_func),
	OPT_CALLBACK('G', "graph-funcs", &ftrace.graph_funcs, "func",
		     "Set graph filter on given functions", parse_filter_func),
	OPT_CALLBACK('g', "nograph-funcs", &ftrace.nograph_funcs, "func",
		     "Set nograph filter on given functions", parse_filter_func),
	OPT_INTEGER('D', "graph-depth", &ftrace.graph_depth,
		    "Max depth for function graph tracer"),
	OPT_END()
	};

	INIT_LIST_HEAD(&ftrace.filters);
	INIT_LIST_HEAD(&ftrace.notrace);
	INIT_LIST_HEAD(&ftrace.graph_funcs);
	INIT_LIST_HEAD(&ftrace.nograph_funcs);

	ret = perf_config(perf_ftrace_config, &ftrace);
	if (ret < 0)
		return -1;

	argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
			    PARSE_OPT_STOP_AT_NON_OPTION);
	if (!argc && target__none(&ftrace.target))
		usage_with_options(ftrace_usage, ftrace_options);

	ret = target__validate(&ftrace.target);
	if (ret) {
		char errbuf[512];

		target__strerror(&ftrace.target, ret, errbuf, 512);
		pr_err("%s\n", errbuf);
		goto out_delete_filters;
	}

	ftrace.evlist = evlist__new();
	if (ftrace.evlist == NULL) {
		ret = -ENOMEM;
		goto out_delete_filters;
	}

	ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);
	if (ret < 0)
		goto out_delete_evlist;

	ret = __cmd_ftrace(&ftrace, argc, argv);

out_delete_evlist:
	evlist__delete(ftrace.evlist);

out_delete_filters:
	delete_filter_func(&ftrace.filters);
	delete_filter_func(&ftrace.notrace);
	delete_filter_func(&ftrace.graph_funcs);
	delete_filter_func(&ftrace.nograph_funcs);

	return ret;
}
Commit	Line	Data
1c6bec5b	1	// SPDX-License-Identifier: GPL-2.0-only
d01f4e8d NK	2	/*
	3	* builtin-ftrace.c
	4	*
	5	* Copyright (c) 2013 LG Electronics, Namhyung Kim <namhyung@kernel.org>
d01f4e8d NK	6	*/
	7
	8	#include "builtin.h"
d01f4e8d	9
a43783ae	10	#include <errno.h>
d01f4e8d NK	11	#include <unistd.h>
d01f4e8d NK	12	#include <signal.h>
f2a39fe8	13	#include <stdlib.h>
a9af6be5	14	#include <fcntl.h>
4208735d	15	#include <poll.h>
c766f3df	16	#include <linux/capability.h>
8520a98d	17	#include <linux/string.h>
d01f4e8d NK	18
d01f4e8d NK	19	#include "debug.h"
8520a98d	20	#include <subcmd/pager.h>
d01f4e8d	21	#include <subcmd/parse-options.h>
20a9ed28	22	#include <api/fs/tracing_path.h>
d01f4e8d NK	23	#include "evlist.h"
d01f4e8d NK	24	#include "target.h"
dc231032	25	#include "cpumap.h"
d01f4e8d	26	#include "thread_map.h"
c766f3df	27	#include "util/cap.h"
b05d1093	28	#include "util/config.h"
d01f4e8d	29
d01f4e8d NK	30	#define DEFAULT_TRACER "function_graph"
	31
	32	struct perf_ftrace {
63503dba	33	struct evlist *evlist;
78b83e8b NK	34	struct target target;
	35	const char *tracer;
	36	struct list_head filters;
	37	struct list_head notrace;
	38	struct list_head graph_funcs;
	39	struct list_head nograph_funcs;
1096c35a	40	int graph_depth;
78b83e8b NK	41	};
	42
	43	struct filter_entry {
	44	struct list_head list;
	45	char name[];
d01f4e8d NK	46	};
	47
	48	static bool done;
	49
	50	static void sig_handler(int sig __maybe_unused)
	51	{
	52	done = true;
	53	}
	54
	55	/*
	56	* perf_evlist__prepare_workload will send a SIGUSR1 if the fork fails, since
	57	* we asked by setting its exec_error to the function below,
	58	* ftrace__workload_exec_failed_signal.
	59	*
	60	* XXX We need to handle this more appropriately, emitting an error, etc.
	61	*/
	62	static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,
	63	siginfo_t *info __maybe_unused,
	64	void *ucontext __maybe_unused)
	65	{
	66	/* workload_exec_errno = info->si_value.sival_int; */
	67	done = true;
	68	}
	69
a9af6be5	70	static int __write_tracing_file(const char name, const char val, bool append)
d01f4e8d NK	71	{
	72	char *file;
	73	int fd, ret = -1;
	74	ssize_t size = strlen(val);
a9af6be5	75	int flags = O_WRONLY;
e7bd9ba2	76	char errbuf[512];
63cd02d8	77	char *val_copy;
d01f4e8d NK	78
	79	file = get_tracing_file(name);
	80	if (!file) {
	81	pr_debug("cannot get tracing file: %s\n", name);
	82	return -1;
	83	}
	84
a9af6be5 NK	85	if (append)
	86	flags \|= O_APPEND;
	87	else
	88	flags \|= O_TRUNC;
	89
	90	fd = open(file, flags);
d01f4e8d	91	if (fd < 0) {
e7bd9ba2 NK	92	pr_debug("cannot open tracing file: %s: %s\n",
e7bd9ba2 NK	93	name, str_error_r(errno, errbuf, sizeof(errbuf)));
d01f4e8d NK	94	goto out;
	95	}
	96
63cd02d8 CD	97	/*
	98	* Copy the original value and append a '\n'. Without this,
	99	* the kernel can hide possible errors.
	100	*/
	101	val_copy = strdup(val);
	102	if (!val_copy)
	103	goto out_close;
	104	val_copy[size] = '\n';
	105
	106	if (write(fd, val_copy, size + 1) == size + 1)
d01f4e8d NK	107	ret = 0;
d01f4e8d NK	108	else
e7bd9ba2 NK	109	pr_debug("write '%s' to tracing/%s failed: %s\n",
e7bd9ba2 NK	110	val, name, str_error_r(errno, errbuf, sizeof(errbuf)));
d01f4e8d	111
63cd02d8 CD	112	free(val_copy);
63cd02d8 CD	113	out_close:
d01f4e8d NK	114	close(fd);
	115	out:
	116	put_tracing_file(file);
	117	return ret;
	118	}
	119
a9af6be5 NK	120	static int write_tracing_file(const char name, const char val)
	121	{
	122	return __write_tracing_file(name, val, false);
	123	}
	124
	125	static int append_tracing_file(const char name, const char val)
	126	{
	127	return __write_tracing_file(name, val, true);
	128	}
	129
dc231032	130	static int reset_tracing_cpu(void);
78b83e8b	131	static void reset_tracing_filters(void);
dc231032	132
d01f4e8d NK	133	static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
	134	{
	135	if (write_tracing_file("tracing_on", "0") < 0)
	136	return -1;
	137
	138	if (write_tracing_file("current_tracer", "nop") < 0)
	139	return -1;
	140
	141	if (write_tracing_file("set_ftrace_pid", " ") < 0)
	142	return -1;
	143
dc231032 NK	144	if (reset_tracing_cpu() < 0)
	145	return -1;
	146
1096c35a NK	147	if (write_tracing_file("max_graph_depth", "0") < 0)
	148	return -1;
	149
78b83e8b	150	reset_tracing_filters();
d01f4e8d NK	151	return 0;
	152	}
	153
a9af6be5 NK	154	static int set_tracing_pid(struct perf_ftrace *ftrace)
	155	{
	156	int i;
	157	char buf[16];
	158
	159	if (target__has_cpu(&ftrace->target))
	160	return 0;
	161
a2f354e3	162	for (i = 0; i < perf_thread_map__nr(ftrace->evlist->core.threads); i++) {
a9af6be5	163	scnprintf(buf, sizeof(buf), "%d",
03617c22	164	ftrace->evlist->core.threads->map[i]);
a9af6be5 NK	165	if (append_tracing_file("set_ftrace_pid", buf) < 0)
	166	return -1;
	167	}
	168	return 0;
	169	}
	170
f854839b	171	static int set_tracing_cpumask(struct perf_cpu_map *cpumap)
dc231032 NK	172	{
	173	char *cpumask;
	174	size_t mask_size;
	175	int ret;
	176	int last_cpu;
	177
	178	last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);
cf30ae72	179	mask_size = last_cpu / 4 + 2; /* one more byte for EOS */
dc231032 NK	180	mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */
	181
	182	cpumask = malloc(mask_size);
	183	if (cpumask == NULL) {
	184	pr_debug("failed to allocate cpu mask\n");
	185	return -1;
	186	}
	187
	188	cpu_map__snprint_mask(cpumap, cpumask, mask_size);
	189
	190	ret = write_tracing_file("tracing_cpumask", cpumask);
	191
	192	free(cpumask);
	193	return ret;
	194	}
	195
	196	static int set_tracing_cpu(struct perf_ftrace *ftrace)
	197	{
f72f901d	198	struct perf_cpu_map *cpumap = ftrace->evlist->core.cpus;
dc231032 NK	199
	200	if (!target__has_cpu(&ftrace->target))
	201	return 0;
	202
	203	return set_tracing_cpumask(cpumap);
	204	}
	205
	206	static int reset_tracing_cpu(void)
	207	{
9c3516d1	208	struct perf_cpu_map *cpumap = perf_cpu_map__new(NULL);
dc231032 NK	209	int ret;
	210
	211	ret = set_tracing_cpumask(cpumap);
38f01d8d	212	perf_cpu_map__put(cpumap);
dc231032 NK	213	return ret;
	214	}
	215
78b83e8b NK	216	static int __set_tracing_filter(const char filter_file, struct list_head funcs)
	217	{
	218	struct filter_entry *pos;
	219
	220	list_for_each_entry(pos, funcs, list) {
	221	if (append_tracing_file(filter_file, pos->name) < 0)
	222	return -1;
	223	}
	224
	225	return 0;
	226	}
	227
	228	static int set_tracing_filters(struct perf_ftrace *ftrace)
	229	{
	230	int ret;
	231
	232	ret = __set_tracing_filter("set_ftrace_filter", &ftrace->filters);
	233	if (ret < 0)
	234	return ret;
	235
	236	ret = __set_tracing_filter("set_ftrace_notrace", &ftrace->notrace);
	237	if (ret < 0)
	238	return ret;
	239
	240	ret = __set_tracing_filter("set_graph_function", &ftrace->graph_funcs);
	241	if (ret < 0)
	242	return ret;
	243
	244	/* old kernels do not have this filter */
	245	__set_tracing_filter("set_graph_notrace", &ftrace->nograph_funcs);
	246
	247	return ret;
	248	}
	249
	250	static void reset_tracing_filters(void)
	251	{
	252	write_tracing_file("set_ftrace_filter", " ");
	253	write_tracing_file("set_ftrace_notrace", " ");
	254	write_tracing_file("set_graph_function", " ");
	255	write_tracing_file("set_graph_notrace", " ");
	256	}
	257
1096c35a NK	258	static int set_tracing_depth(struct perf_ftrace *ftrace)
	259	{
	260	char buf[16];
	261
	262	if (ftrace->graph_depth == 0)
	263	return 0;
	264
	265	if (ftrace->graph_depth < 0) {
	266	pr_err("invalid graph depth: %d\n", ftrace->graph_depth);
	267	return -1;
	268	}
	269
	270	snprintf(buf, sizeof(buf), "%d", ftrace->graph_depth);
	271
	272	if (write_tracing_file("max_graph_depth", buf) < 0)
	273	return -1;
	274
	275	return 0;
	276	}
	277
d01f4e8d NK	278	static int __cmd_ftrace(struct perf_ftrace ftrace, int argc, const char *argv)
	279	{
	280	char *trace_file;
	281	int trace_fd;
d01f4e8d NK	282	char buf[4096];
	283	struct pollfd pollfd = {
	284	.events = POLLIN,
	285	};
	286
c766f3df	287	if (!perf_cap__capable(CAP_SYS_ADMIN)) {
73e5de70 ACM	288	pr_err("ftrace only works for %s!\n",
	289	#ifdef HAVE_LIBCAP_SUPPORT
	290	"users with the SYS_ADMIN capability"
	291	#else
	292	"root"
	293	#endif
	294	);
d01f4e8d NK	295	return -1;
	296	}
	297
d01f4e8d NK	298	signal(SIGINT, sig_handler);
	299	signal(SIGUSR1, sig_handler);
	300	signal(SIGCHLD, sig_handler);
58335964	301	signal(SIGPIPE, sig_handler);
d01f4e8d	302
63cd02d8 CD	303	if (reset_tracing_files(ftrace) < 0) {
63cd02d8 CD	304	pr_err("failed to reset ftrace\n");
a9af6be5	305	goto out;
63cd02d8	306	}
d01f4e8d NK	307
	308	/* reset ftrace buffer */
	309	if (write_tracing_file("trace", "0") < 0)
	310	goto out;
	311
a9af6be5 NK	312	if (argc && perf_evlist__prepare_workload(ftrace->evlist,
	313	&ftrace->target, argv, false,
	314	ftrace__workload_exec_failed_signal) < 0) {
d01f4e8d NK	315	goto out;
	316	}
	317
a9af6be5 NK	318	if (set_tracing_pid(ftrace) < 0) {
	319	pr_err("failed to set ftrace pid\n");
	320	goto out_reset;
d01f4e8d NK	321	}
d01f4e8d NK	322
dc231032 NK	323	if (set_tracing_cpu(ftrace) < 0) {
	324	pr_err("failed to set tracing cpumask\n");
	325	goto out_reset;
	326	}
	327
78b83e8b NK	328	if (set_tracing_filters(ftrace) < 0) {
	329	pr_err("failed to set tracing filters\n");
	330	goto out_reset;
	331	}
	332
1096c35a NK	333	if (set_tracing_depth(ftrace) < 0) {
	334	pr_err("failed to set graph depth\n");
	335	goto out_reset;
	336	}
	337
a9af6be5 NK	338	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
	339	pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
	340	goto out_reset;
d01f4e8d NK	341	}
d01f4e8d NK	342
29681bc5 NK	343	setup_pager();
29681bc5 NK	344
d01f4e8d NK	345	trace_file = get_tracing_file("trace_pipe");
	346	if (!trace_file) {
	347	pr_err("failed to open trace_pipe\n");
a9af6be5	348	goto out_reset;
d01f4e8d NK	349	}
	350
	351	trace_fd = open(trace_file, O_RDONLY);
	352
	353	put_tracing_file(trace_file);
	354
	355	if (trace_fd < 0) {
	356	pr_err("failed to open trace_pipe\n");
a9af6be5	357	goto out_reset;
d01f4e8d NK	358	}
	359
	360	fcntl(trace_fd, F_SETFL, O_NONBLOCK);
	361	pollfd.fd = trace_fd;
	362
	363	if (write_tracing_file("tracing_on", "1") < 0) {
	364	pr_err("can't enable tracing\n");
	365	goto out_close_fd;
	366	}
	367
	368	perf_evlist__start_workload(ftrace->evlist);
	369
	370	while (!done) {
	371	if (poll(&pollfd, 1, -1) < 0)
	372	break;
	373
	374	if (pollfd.revents & POLLIN) {
	375	int n = read(trace_fd, buf, sizeof(buf));
	376	if (n < 0)
	377	break;
	378	if (fwrite(buf, n, 1, stdout) != 1)
	379	break;
	380	}
	381	}
	382
	383	write_tracing_file("tracing_on", "0");
	384
	385	/* read remaining buffer contents */
	386	while (true) {
	387	int n = read(trace_fd, buf, sizeof(buf));
	388	if (n <= 0)
	389	break;
	390	if (fwrite(buf, n, 1, stdout) != 1)
	391	break;
	392	}
	393
	394	out_close_fd:
	395	close(trace_fd);
a9af6be5	396	out_reset:
d01f4e8d	397	reset_tracing_files(ftrace);
a9af6be5	398	out:
d01f4e8d NK	399	return done ? 0 : -1;
	400	}
	401
b05d1093 TS	402	static int perf_ftrace_config(const char var, const char value, void *cb)
	403	{
	404	struct perf_ftrace *ftrace = cb;
	405
8e99b6d4	406	if (!strstarts(var, "ftrace."))
b05d1093 TS	407	return 0;
	408
	409	if (strcmp(var, "ftrace.tracer"))
	410	return -1;
	411
	412	if (!strcmp(value, "function_graph") \|\|
	413	!strcmp(value, "function")) {
	414	ftrace->tracer = value;
	415	return 0;
	416	}
	417
	418	pr_err("Please select \"function_graph\" (default) or \"function\"\n");
	419	return -1;
	420	}
	421
78b83e8b NK	422	static int parse_filter_func(const struct option opt, const char str,
	423	int unset __maybe_unused)
	424	{
	425	struct list_head *head = opt->value;
	426	struct filter_entry *entry;
	427
	428	entry = malloc(sizeof(*entry) + strlen(str) + 1);
	429	if (entry == NULL)
	430	return -ENOMEM;
	431
	432	strcpy(entry->name, str);
	433	list_add_tail(&entry->list, head);
	434
	435	return 0;
	436	}
	437
	438	static void delete_filter_func(struct list_head *head)
	439	{
	440	struct filter_entry pos, tmp;
	441
	442	list_for_each_entry_safe(pos, tmp, head, list) {
e56fbc9d	443	list_del_init(&pos->list);
78b83e8b NK	444	free(pos);
	445	}
	446	}
	447
b0ad8ea6	448	int cmd_ftrace(int argc, const char **argv)
d01f4e8d NK	449	{
	450	int ret;
	451	struct perf_ftrace ftrace = {
bf062bd2	452	.tracer = DEFAULT_TRACER,
d01f4e8d NK	453	.target = { .uid = UINT_MAX, },
	454	};
	455	const char * const ftrace_usage[] = {
a9af6be5	456	"perf ftrace [<options>] [<command>]",
d01f4e8d NK	457	"perf ftrace [<options>] -- <command> [<options>]",
	458	NULL
	459	};
	460	const struct option ftrace_options[] = {
	461	OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
ec347870	462	"tracer to use: function_graph(default) or function"),
a9af6be5 NK	463	OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
a9af6be5 NK	464	"trace on existing process id"),
d01f4e8d NK	465	OPT_INCR('v', "verbose", &verbose,
d01f4e8d NK	466	"be more verbose"),
dc231032 NK	467	OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
	468	"system-wide collection from all CPUs"),
	469	OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
	470	"list of cpus to monitor"),
78b83e8b NK	471	OPT_CALLBACK('T', "trace-funcs", &ftrace.filters, "func",
	472	"trace given functions only", parse_filter_func),
	473	OPT_CALLBACK('N', "notrace-funcs", &ftrace.notrace, "func",
	474	"do not trace given functions", parse_filter_func),
	475	OPT_CALLBACK('G', "graph-funcs", &ftrace.graph_funcs, "func",
	476	"Set graph filter on given functions", parse_filter_func),
	477	OPT_CALLBACK('g', "nograph-funcs", &ftrace.nograph_funcs, "func",
	478	"Set nograph filter on given functions", parse_filter_func),
1096c35a NK	479	OPT_INTEGER('D', "graph-depth", &ftrace.graph_depth,
1096c35a NK	480	"Max depth for function graph tracer"),
d01f4e8d NK	481	OPT_END()
	482	};
	483
78b83e8b NK	484	INIT_LIST_HEAD(&ftrace.filters);
	485	INIT_LIST_HEAD(&ftrace.notrace);
	486	INIT_LIST_HEAD(&ftrace.graph_funcs);
	487	INIT_LIST_HEAD(&ftrace.nograph_funcs);
	488
b05d1093 TS	489	ret = perf_config(perf_ftrace_config, &ftrace);
	490	if (ret < 0)
	491	return -1;
	492
d01f4e8d NK	493	argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
d01f4e8d NK	494	PARSE_OPT_STOP_AT_NON_OPTION);
a9af6be5	495	if (!argc && target__none(&ftrace.target))
d01f4e8d NK	496	usage_with_options(ftrace_usage, ftrace_options);
d01f4e8d NK	497
a9af6be5 NK	498	ret = target__validate(&ftrace.target);
	499	if (ret) {
	500	char errbuf[512];
	501
	502	target__strerror(&ftrace.target, ret, errbuf, 512);
	503	pr_err("%s\n", errbuf);
78b83e8b	504	goto out_delete_filters;
a9af6be5 NK	505	}
a9af6be5 NK	506
0f98b11c	507	ftrace.evlist = evlist__new();
78b83e8b NK	508	if (ftrace.evlist == NULL) {
	509	ret = -ENOMEM;
	510	goto out_delete_filters;
	511	}
d01f4e8d NK	512
	513	ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);
	514	if (ret < 0)
	515	goto out_delete_evlist;
	516
d01f4e8d NK	517	ret = __cmd_ftrace(&ftrace, argc, argv);
	518
	519	out_delete_evlist:
c12995a5	520	evlist__delete(ftrace.evlist);
d01f4e8d	521
78b83e8b NK	522	out_delete_filters:
	523	delete_filter_func(&ftrace.filters);
	524	delete_filter_func(&ftrace.notrace);
	525	delete_filter_func(&ftrace.graph_funcs);
	526	delete_filter_func(&ftrace.nograph_funcs);
	527
d01f4e8d NK	528	return ret;
d01f4e8d NK	529	}