tools/perf/perf.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * perf.c
  *
  * Performance analysis utility.
  *
  * This is the main hub from which the sub-commands (perf stat,
  * perf top, perf record, perf report, etc.) are started.
  */
 #include "builtin.h"

 #include "util/env.h"
 #include <subcmd/exec-cmd.h>
 #include "util/config.h"
 #include <subcmd/run-command.h>
 #include "util/parse-events.h"
 #include <subcmd/parse-options.h>
 #include "util/bpf-loader.h"
 #include "util/debug.h"
 #include "util/event.h"
 #include <api/fs/fs.h>
 #include <api/fs/tracing_path.h>
 #include <errno.h>
 #include <pthread.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <time.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
 #include <linux/kernel.h>
 #include <linux/zalloc.h>

 const char perf_usage_string[] =
 	"perf [--version] [--help] [OPTIONS] COMMAND [ARGS]";

 const char perf_more_info_string[] =
 	"See 'perf help COMMAND' for more information on a specific command.";

 static int use_pager = -1;
 const char *input_name;

 struct cmd_struct {
 	const char *cmd;
 	int (*fn)(int, const char **);
 	int option;
 };

 static struct cmd_struct commands[] = {
 	{ "buildid-cache", cmd_buildid_cache, 0 },
 	{ "buildid-list", cmd_buildid_list, 0 },
 	{ "config",	cmd_config,	0 },
 	{ "c2c",	cmd_c2c,	0 },
 	{ "diff",	cmd_diff,	0 },
 	{ "evlist",	cmd_evlist,	0 },
 	{ "help",	cmd_help,	0 },
 	{ "kallsyms",	cmd_kallsyms,	0 },
 	{ "list",	cmd_list,	0 },
 	{ "record",	cmd_record,	0 },
 	{ "report",	cmd_report,	0 },
 	{ "bench",	cmd_bench,	0 },
 	{ "stat",	cmd_stat,	0 },
 	{ "timechart",	cmd_timechart,	0 },
 	{ "top",	cmd_top,	0 },
 	{ "annotate",	cmd_annotate,	0 },
 	{ "version",	cmd_version,	0 },
 	{ "script",	cmd_script,	0 },
 	{ "sched",	cmd_sched,	0 },
 #ifdef HAVE_LIBELF_SUPPORT
 	{ "probe",	cmd_probe,	0 },
 #endif
 	{ "kmem",	cmd_kmem,	0 },
 	{ "lock",	cmd_lock,	0 },
 	{ "kvm",	cmd_kvm,	0 },
 	{ "test",	cmd_test,	0 },
 #if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
 	{ "trace",	cmd_trace,	0 },
 #endif
 	{ "inject",	cmd_inject,	0 },
 	{ "mem",	cmd_mem,	0 },
 	{ "data",	cmd_data,	0 },
 	{ "ftrace",	cmd_ftrace,	0 },
 };

 struct pager_config {
 	const char *cmd;
 	int val;
 };

 static int pager_command_config(const char *var, const char *value, void *data)
 {
 	struct pager_config *c = data;
 	if (strstarts(var, "pager.") && !strcmp(var + 6, c->cmd))
 		c->val = perf_config_bool(var, value);
 	return 0;
 }

 /* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
 static int check_pager_config(const char *cmd)
 {
 	int err;
 	struct pager_config c;
 	c.cmd = cmd;
 	c.val = -1;
 	err = perf_config(pager_command_config, &c);
 	return err ?: c.val;
 }

 static int browser_command_config(const char *var, const char *value, void *data)
 {
 	struct pager_config *c = data;
 	if (strstarts(var, "tui.") && !strcmp(var + 4, c->cmd))
 		c->val = perf_config_bool(var, value);
 	if (strstarts(var, "gtk.") && !strcmp(var + 4, c->cmd))
 		c->val = perf_config_bool(var, value) ? 2 : 0;
 	return 0;
 }

 /*
  * returns 0 for "no tui", 1 for "use tui", 2 for "use gtk",
  * and -1 for "not specified"
  */
 static int check_browser_config(const char *cmd)
 {
 	int err;
 	struct pager_config c;
 	c.cmd = cmd;
 	c.val = -1;
 	err = perf_config(browser_command_config, &c);
 	return err ?: c.val;
 }

 static void commit_pager_choice(void)
 {
 	switch (use_pager) {
 	case 0:
 		setenv(PERF_PAGER_ENVIRONMENT, "cat", 1);
 		break;
 	case 1:
 		/* setup_pager(); */
 		break;
 	default:
 		break;
 	}
 }

 struct option options[] = {
 	OPT_ARGUMENT("help", "help"),
 	OPT_ARGUMENT("version", "version"),
 	OPT_ARGUMENT("exec-path", "exec-path"),
 	OPT_ARGUMENT("html-path", "html-path"),
 	OPT_ARGUMENT("paginate", "paginate"),
 	OPT_ARGUMENT("no-pager", "no-pager"),
 	OPT_ARGUMENT("debugfs-dir", "debugfs-dir"),
 	OPT_ARGUMENT("buildid-dir", "buildid-dir"),
 	OPT_ARGUMENT("list-cmds", "list-cmds"),
 	OPT_ARGUMENT("list-opts", "list-opts"),
 	OPT_ARGUMENT("debug", "debug"),
 	OPT_END()
 };

 static int handle_options(const char ***argv, int *argc, int *envchanged)
 {
 	int handled = 0;

 	while (*argc > 0) {
 		const char *cmd = (*argv)[0];
 		if (cmd[0] != '-')
 			break;

 		/*
 		 * For legacy reasons, the "version" and "help"
 		 * commands can be written with "--" prepended
 		 * to make them look like flags.
 		 */
 		if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
 			break;

 		/*
 		 * Shortcut for '-h' and '-v' options to invoke help
 		 * and version command.
 		 */
 		if (!strcmp(cmd, "-h")) {
 			(*argv)[0] = "--help";
 			break;
 		}

 		if (!strcmp(cmd, "-v")) {
 			(*argv)[0] = "--version";
 			break;
 		}

 		if (!strcmp(cmd, "-vv")) {
 			(*argv)[0] = "version";
 			version_verbose = 1;
 			break;
 		}

 		/*
 		 * Check remaining flags.
 		 */
 		if (strstarts(cmd, CMD_EXEC_PATH)) {
 			cmd += strlen(CMD_EXEC_PATH);
 			if (*cmd == '=')
 				set_argv_exec_path(cmd + 1);
 			else {
 				puts(get_argv_exec_path());
 				exit(0);
 			}
 		} else if (!strcmp(cmd, "--html-path")) {
 			puts(system_path(PERF_HTML_PATH));
 			exit(0);
 		} else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
 			use_pager = 1;
 		} else if (!strcmp(cmd, "--no-pager")) {
 			use_pager = 0;
 			if (envchanged)
 				*envchanged = 1;
 		} else if (!strcmp(cmd, "--debugfs-dir")) {
 			if (*argc < 2) {
 				fprintf(stderr, "No directory given for --debugfs-dir.\n");
 				usage(perf_usage_string);
 			}
 			tracing_path_set((*argv)[1]);
 			if (envchanged)
 				*envchanged = 1;
 			(*argv)++;
 			(*argc)--;
 		} else if (!strcmp(cmd, "--buildid-dir")) {
 			if (*argc < 2) {
 				fprintf(stderr, "No directory given for --buildid-dir.\n");
 				usage(perf_usage_string);
 			}
 			set_buildid_dir((*argv)[1]);
 			if (envchanged)
 				*envchanged = 1;
 			(*argv)++;
 			(*argc)--;
 		} else if (strstarts(cmd, CMD_DEBUGFS_DIR)) {
 			tracing_path_set(cmd + strlen(CMD_DEBUGFS_DIR));
 			fprintf(stderr, "dir: %s\n", tracing_path_mount());
 			if (envchanged)
 				*envchanged = 1;
 		} else if (!strcmp(cmd, "--list-cmds")) {
 			unsigned int i;

 			for (i = 0; i < ARRAY_SIZE(commands); i++) {
 				struct cmd_struct *p = commands+i;
 				printf("%s ", p->cmd);
 			}
 			putchar('\n');
 			exit(0);
 		} else if (!strcmp(cmd, "--list-opts")) {
 			unsigned int i;

 			for (i = 0; i < ARRAY_SIZE(options)-1; i++) {
 				struct option *p = options+i;
 				printf("--%s ", p->long_name);
 			}
 			putchar('\n');
 			exit(0);
 		} else if (!strcmp(cmd, "--debug")) {
 			if (*argc < 2) {
 				fprintf(stderr, "No variable specified for --debug.\n");
 				usage(perf_usage_string);
 			}
 			if (perf_debug_option((*argv)[1]))
 				usage(perf_usage_string);

 			(*argv)++;
 			(*argc)--;
 		} else {
 			fprintf(stderr, "Unknown option: %s\n", cmd);
 			usage(perf_usage_string);
 		}

 		(*argv)++;
 		(*argc)--;
 		handled++;
 	}
 	return handled;
 }

 #define RUN_SETUP	(1<<0)
 #define USE_PAGER	(1<<1)

 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 {
 	int status;
 	struct stat st;
 	char sbuf[STRERR_BUFSIZE];

 	if (use_browser == -1)
 		use_browser = check_browser_config(p->cmd);

 	if (use_pager == -1 && p->option & RUN_SETUP)
 		use_pager = check_pager_config(p->cmd);
 	if (use_pager == -1 && p->option & USE_PAGER)
 		use_pager = 1;
 	commit_pager_choice();

 	perf_env__init(&perf_env);
 	perf_env__set_cmdline(&perf_env, argc, argv);
 	status = p->fn(argc, argv);
 	perf_config__exit();
 	exit_browser(status);
 	perf_env__exit(&perf_env);
 	bpf__clear();

 	if (status)
 		return status & 0xff;

 	/* Somebody closed stdout? */
 	if (fstat(fileno(stdout), &st))
 		return 0;
 	/* Ignore write errors for pipes and sockets.. */
 	if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 		return 0;

 	status = 1;
 	/* Check for ENOSPC and EIO errors.. */
 	if (fflush(stdout)) {
 		fprintf(stderr, "write failure on standard output: %s",
 			str_error_r(errno, sbuf, sizeof(sbuf)));
 		goto out;
 	}
 	if (ferror(stdout)) {
 		fprintf(stderr, "unknown write failure on standard output");
 		goto out;
 	}
 	if (fclose(stdout)) {
 		fprintf(stderr, "close failed on standard output: %s",
 			str_error_r(errno, sbuf, sizeof(sbuf)));
 		goto out;
 	}
 	status = 0;
 out:
 	return status;
 }

 static void handle_internal_command(int argc, const char **argv)
 {
 	const char *cmd = argv[0];
 	unsigned int i;

 	/* Turn "perf cmd --help" into "perf help cmd" */
 	if (argc > 1 && !strcmp(argv[1], "--help")) {
 		argv[1] = argv[0];
 		argv[0] = cmd = "help";
 	}

 	for (i = 0; i < ARRAY_SIZE(commands); i++) {
 		struct cmd_struct *p = commands+i;
 		if (strcmp(p->cmd, cmd))
 			continue;
 		exit(run_builtin(p, argc, argv));
 	}
 }

 static void execv_dashed_external(const char **argv)
 {
 	char *cmd;
 	const char *tmp;
 	int status;

 	if (asprintf(&cmd, "perf-%s", argv[0]) < 0)
 		goto do_die;

 	/*
 	 * argv[0] must be the perf command, but the argv array
 	 * belongs to the caller, and may be reused in
 	 * subsequent loop iterations. Save argv[0] and
 	 * restore it on error.
 	 */
 	tmp = argv[0];
 	argv[0] = cmd;

 	/*
 	 * if we fail because the command is not found, it is
 	 * OK to return. Otherwise, we just pass along the status code.
 	 */
 	status = run_command_v_opt(argv, 0);
 	if (status != -ERR_RUN_COMMAND_EXEC) {
 		if (IS_RUN_COMMAND_ERR(status)) {
 do_die:
 			pr_err("FATAL: unable to run '%s'", argv[0]);
 			status = -128;
 		}
 		exit(-status);
 	}
 	errno = ENOENT; /* as if we called execvp */

 	argv[0] = tmp;
 	zfree(&cmd);
 }

 static int run_argv(int *argcp, const char ***argv)
 {
 	/* See if it's an internal command */
 	handle_internal_command(*argcp, *argv);

 	/* .. then try the external ones */
 	execv_dashed_external(*argv);
 	return 0;
 }

 static void pthread__block_sigwinch(void)
 {
 	sigset_t set;

 	sigemptyset(&set);
 	sigaddset(&set, SIGWINCH);
 	pthread_sigmask(SIG_BLOCK, &set, NULL);
 }

 void pthread__unblock_sigwinch(void)
 {
 	sigset_t set;

 	sigemptyset(&set);
 	sigaddset(&set, SIGWINCH);
 	pthread_sigmask(SIG_UNBLOCK, &set, NULL);
 }

 int main(int argc, const char **argv)
 {
 	int err;
 	const char *cmd;
 	char sbuf[STRERR_BUFSIZE];

 	/* libsubcmd init */
 	exec_cmd_init("perf", PREFIX, PERF_EXEC_PATH, EXEC_PATH_ENVIRONMENT);
 	pager_init(PERF_PAGER_ENVIRONMENT);

 	/* The page_size is placed in util object. */
 	page_size = sysconf(_SC_PAGE_SIZE);

 	cmd = extract_argv0_path(argv[0]);
 	if (!cmd)
 		cmd = "perf-help";

 	srandom(time(NULL));

 	err = perf_config(perf_default_config, NULL);
 	if (err)
 		return err;
 	set_buildid_dir(NULL);

 	/*
 	 * "perf-xxxx" is the same as "perf xxxx", but we obviously:
 	 *
 	 *  - cannot take flags in between the "perf" and the "xxxx".
 	 *  - cannot execute it externally (since it would just do
 	 *    the same thing over again)
 	 *
 	 * So we just directly call the internal command handler. If that one
 	 * fails to handle this, then maybe we just run a renamed perf binary
 	 * that contains a dash in its name. To handle this scenario, we just
 	 * fall through and ignore the "xxxx" part of the command string.
 	 */
 	if (strstarts(cmd, "perf-")) {
 		cmd += 5;
 		argv[0] = cmd;
 		handle_internal_command(argc, argv);
 		/*
 		 * If the command is handled, the above function does not
 		 * return undo changes and fall through in such a case.
 		 */
 		cmd -= 5;
 		argv[0] = cmd;
 	}
 	if (strstarts(cmd, "trace")) {
 #if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
 		setup_path();
 		argv[0] = "trace";
 		return cmd_trace(argc, argv);
 #else
 		fprintf(stderr,
 			"trace command not available: missing audit-libs devel package at build time.\n");
 		goto out;
 #endif
 	}
 	/* Look for flags.. */
 	argv++;
 	argc--;
 	handle_options(&argv, &argc, NULL);
 	commit_pager_choice();

 	if (argc > 0) {
 		if (strstarts(argv[0], "--"))
 			argv[0] += 2;
 	} else {
 		/* The user didn't specify a command; give them help */
 		printf("\n usage: %s\n\n", perf_usage_string);
 		list_common_cmds_help();
 		printf("\n %s\n\n", perf_more_info_string);
 		goto out;
 	}
 	cmd = argv[0];

 	test_attr__init();

 	/*
 	 * We use PATH to find perf commands, but we prepend some higher
 	 * precedence paths: the "--exec-path" option, the PERF_EXEC_PATH
 	 * environment, and the $(perfexecdir) from the Makefile at build
 	 * time.
 	 */
 	setup_path();
 	/*
 	 * Block SIGWINCH notifications so that the thread that wants it can
 	 * unblock and get syscalls like select interrupted instead of waiting
 	 * forever while the signal goes to some other non interested thread.
 	 */
 	pthread__block_sigwinch();

 	perf_debug_setup();

 	while (1) {
 		static int done_help;

 		run_argv(&argc, &argv);

 		if (errno != ENOENT)
 			break;

 		if (!done_help) {
 			cmd = argv[0] = help_unknown_cmd(cmd);
 			done_help = 1;
 		} else
 			break;
 	}

 	fprintf(stderr, "Failed to run command '%s': %s\n",
 		cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
 out:
 	return 1;
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* perf.c
	*
	* Performance analysis utility.
	*
	* This is the main hub from which the sub-commands (perf stat,
	* perf top, perf record, perf report, etc.) are started.
	*/
	#include "builtin.h"

	#include "util/env.h"
	#include <subcmd/exec-cmd.h>
	#include "util/config.h"
	#include <subcmd/run-command.h>
	#include "util/parse-events.h"
	#include <subcmd/parse-options.h>
	#include "util/bpf-loader.h"
	#include "util/debug.h"
	#include "util/event.h"
	#include <api/fs/fs.h>
	#include <api/fs/tracing_path.h>
	#include <errno.h>
	#include <pthread.h>
	#include <signal.h>
	#include <stdlib.h>
	#include <time.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <unistd.h>
	#include <linux/kernel.h>
	#include <linux/zalloc.h>

	const char perf_usage_string[] =
	"perf [--version] [--help] [OPTIONS] COMMAND [ARGS]";

	const char perf_more_info_string[] =
	"See 'perf help COMMAND' for more information on a specific command.";

	static int use_pager = -1;
	const char *input_name;

	struct cmd_struct {
	const char *cmd;
	int (fn)(int, const char *);
	int option;
	};

	static struct cmd_struct commands[] = {
	{ "buildid-cache", cmd_buildid_cache, 0 },
	{ "buildid-list", cmd_buildid_list, 0 },
	{ "config", cmd_config, 0 },
	{ "c2c", cmd_c2c, 0 },
	{ "diff", cmd_diff, 0 },
	{ "evlist", cmd_evlist, 0 },
	{ "help", cmd_help, 0 },
	{ "kallsyms", cmd_kallsyms, 0 },
	{ "list", cmd_list, 0 },
	{ "record", cmd_record, 0 },
	{ "report", cmd_report, 0 },
	{ "bench", cmd_bench, 0 },
	{ "stat", cmd_stat, 0 },
	{ "timechart", cmd_timechart, 0 },
	{ "top", cmd_top, 0 },
	{ "annotate", cmd_annotate, 0 },
	{ "version", cmd_version, 0 },
	{ "script", cmd_script, 0 },
	{ "sched", cmd_sched, 0 },
	#ifdef HAVE_LIBELF_SUPPORT
	{ "probe", cmd_probe, 0 },
	#endif
	{ "kmem", cmd_kmem, 0 },
	{ "lock", cmd_lock, 0 },
	{ "kvm", cmd_kvm, 0 },
	{ "test", cmd_test, 0 },
	#if defined(HAVE_LIBAUDIT_SUPPORT) \|\| defined(HAVE_SYSCALL_TABLE_SUPPORT)
	{ "trace", cmd_trace, 0 },
	#endif
	{ "inject", cmd_inject, 0 },
	{ "mem", cmd_mem, 0 },
	{ "data", cmd_data, 0 },
	{ "ftrace", cmd_ftrace, 0 },
	};

	struct pager_config {
	const char *cmd;
	int val;
	};

	static int pager_command_config(const char var, const char value, void *data)
	{
	struct pager_config *c = data;
	if (strstarts(var, "pager.") && !strcmp(var + 6, c->cmd))
	c->val = perf_config_bool(var, value);
	return 0;
	}

	/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
	static int check_pager_config(const char *cmd)
	{
	int err;
	struct pager_config c;
	c.cmd = cmd;
	c.val = -1;
	err = perf_config(pager_command_config, &c);
	return err ?: c.val;
	}

	static int browser_command_config(const char var, const char value, void *data)
	{
	struct pager_config *c = data;
	if (strstarts(var, "tui.") && !strcmp(var + 4, c->cmd))
	c->val = perf_config_bool(var, value);
	if (strstarts(var, "gtk.") && !strcmp(var + 4, c->cmd))
	c->val = perf_config_bool(var, value) ? 2 : 0;
	return 0;
	}

	/*
	* returns 0 for "no tui", 1 for "use tui", 2 for "use gtk",
	* and -1 for "not specified"
	*/
	static int check_browser_config(const char *cmd)
	{
	int err;
	struct pager_config c;
	c.cmd = cmd;
	c.val = -1;
	err = perf_config(browser_command_config, &c);
	return err ?: c.val;
	}

	static void commit_pager_choice(void)
	{
	switch (use_pager) {
	case 0:
	setenv(PERF_PAGER_ENVIRONMENT, "cat", 1);
	break;
	case 1:
	/* setup_pager(); */
	break;
	default:
	break;
	}
	}

	struct option options[] = {
	OPT_ARGUMENT("help", "help"),
	OPT_ARGUMENT("version", "version"),
	OPT_ARGUMENT("exec-path", "exec-path"),
	OPT_ARGUMENT("html-path", "html-path"),
	OPT_ARGUMENT("paginate", "paginate"),
	OPT_ARGUMENT("no-pager", "no-pager"),
	OPT_ARGUMENT("debugfs-dir", "debugfs-dir"),
	OPT_ARGUMENT("buildid-dir", "buildid-dir"),
	OPT_ARGUMENT("list-cmds", "list-cmds"),
	OPT_ARGUMENT("list-opts", "list-opts"),
	OPT_ARGUMENT("debug", "debug"),
	OPT_END()
	};

	static int handle_options(const char **argv, int argc, int *envchanged)
	{
	int handled = 0;

	while (*argc > 0) {
	const char cmd = (argv)[0];
	if (cmd[0] != '-')
	break;

	/*
	* For legacy reasons, the "version" and "help"
	* commands can be written with "--" prepended
	* to make them look like flags.
	*/
	if (!strcmp(cmd, "--help") \|\| !strcmp(cmd, "--version"))
	break;

	/*
	* Shortcut for '-h' and '-v' options to invoke help
	* and version command.
	*/
	if (!strcmp(cmd, "-h")) {
	(*argv)[0] = "--help";
	break;
	}

	if (!strcmp(cmd, "-v")) {
	(*argv)[0] = "--version";
	break;
	}

	if (!strcmp(cmd, "-vv")) {
	(*argv)[0] = "version";
	version_verbose = 1;
	break;
	}

	/*
	* Check remaining flags.
	*/
	if (strstarts(cmd, CMD_EXEC_PATH)) {
	cmd += strlen(CMD_EXEC_PATH);
	if (*cmd == '=')
	set_argv_exec_path(cmd + 1);
	else {
	puts(get_argv_exec_path());
	exit(0);
	}
	} else if (!strcmp(cmd, "--html-path")) {
	puts(system_path(PERF_HTML_PATH));
	exit(0);
	} else if (!strcmp(cmd, "-p") \|\| !strcmp(cmd, "--paginate")) {
	use_pager = 1;
	} else if (!strcmp(cmd, "--no-pager")) {
	use_pager = 0;
	if (envchanged)
	*envchanged = 1;
	} else if (!strcmp(cmd, "--debugfs-dir")) {
	if (*argc < 2) {
	fprintf(stderr, "No directory given for --debugfs-dir.\n");
	usage(perf_usage_string);
	}
	tracing_path_set((*argv)[1]);
	if (envchanged)
	*envchanged = 1;
	(*argv)++;
	(*argc)--;
	} else if (!strcmp(cmd, "--buildid-dir")) {
	if (*argc < 2) {
	fprintf(stderr, "No directory given for --buildid-dir.\n");
	usage(perf_usage_string);
	}
	set_buildid_dir((*argv)[1]);
	if (envchanged)
	*envchanged = 1;
	(*argv)++;
	(*argc)--;
	} else if (strstarts(cmd, CMD_DEBUGFS_DIR)) {
	tracing_path_set(cmd + strlen(CMD_DEBUGFS_DIR));
	fprintf(stderr, "dir: %s\n", tracing_path_mount());
	if (envchanged)
	*envchanged = 1;
	} else if (!strcmp(cmd, "--list-cmds")) {
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(commands); i++) {
	struct cmd_struct *p = commands+i;
	printf("%s ", p->cmd);
	}
	putchar('\n');
	exit(0);
	} else if (!strcmp(cmd, "--list-opts")) {
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(options)-1; i++) {
	struct option *p = options+i;
	printf("--%s ", p->long_name);
	}
	putchar('\n');
	exit(0);
	} else if (!strcmp(cmd, "--debug")) {
	if (*argc < 2) {
	fprintf(stderr, "No variable specified for --debug.\n");
	usage(perf_usage_string);
	}
	if (perf_debug_option((*argv)[1]))
	usage(perf_usage_string);

	(*argv)++;
	(*argc)--;
	} else {
	fprintf(stderr, "Unknown option: %s\n", cmd);
	usage(perf_usage_string);
	}

	(*argv)++;
	(*argc)--;
	handled++;
	}
	return handled;
	}

	#define RUN_SETUP (1<<0)
	#define USE_PAGER (1<<1)

	static int run_builtin(struct cmd_struct p, int argc, const char *argv)
	{
	int status;
	struct stat st;
	char sbuf[STRERR_BUFSIZE];

	if (use_browser == -1)
	use_browser = check_browser_config(p->cmd);

	if (use_pager == -1 && p->option & RUN_SETUP)
	use_pager = check_pager_config(p->cmd);
	if (use_pager == -1 && p->option & USE_PAGER)
	use_pager = 1;
	commit_pager_choice();

	perf_env__init(&perf_env);
	perf_env__set_cmdline(&perf_env, argc, argv);
	status = p->fn(argc, argv);
	perf_config__exit();
	exit_browser(status);
	perf_env__exit(&perf_env);
	bpf__clear();

	if (status)
	return status & 0xff;

	/* Somebody closed stdout? */
	if (fstat(fileno(stdout), &st))
	return 0;
	/* Ignore write errors for pipes and sockets.. */
	if (S_ISFIFO(st.st_mode) \|\| S_ISSOCK(st.st_mode))
	return 0;

	status = 1;
	/* Check for ENOSPC and EIO errors.. */
	if (fflush(stdout)) {
	fprintf(stderr, "write failure on standard output: %s",
	str_error_r(errno, sbuf, sizeof(sbuf)));
	goto out;
	}
	if (ferror(stdout)) {
	fprintf(stderr, "unknown write failure on standard output");
	goto out;
	}
	if (fclose(stdout)) {
	fprintf(stderr, "close failed on standard output: %s",
	str_error_r(errno, sbuf, sizeof(sbuf)));
	goto out;
	}
	status = 0;
	out:
	return status;
	}

	static void handle_internal_command(int argc, const char **argv)
	{
	const char *cmd = argv[0];
	unsigned int i;

	/* Turn "perf cmd --help" into "perf help cmd" */
	if (argc > 1 && !strcmp(argv[1], "--help")) {
	argv[1] = argv[0];
	argv[0] = cmd = "help";
	}

	for (i = 0; i < ARRAY_SIZE(commands); i++) {
	struct cmd_struct *p = commands+i;
	if (strcmp(p->cmd, cmd))
	continue;
	exit(run_builtin(p, argc, argv));
	}
	}

	static void execv_dashed_external(const char **argv)
	{
	char *cmd;
	const char *tmp;
	int status;

	if (asprintf(&cmd, "perf-%s", argv[0]) < 0)
	goto do_die;

	/*
	* argv[0] must be the perf command, but the argv array
	* belongs to the caller, and may be reused in
	* subsequent loop iterations. Save argv[0] and
	* restore it on error.
	*/
	tmp = argv[0];
	argv[0] = cmd;

	/*
	* if we fail because the command is not found, it is
	* OK to return. Otherwise, we just pass along the status code.
	*/
	status = run_command_v_opt(argv, 0);
	if (status != -ERR_RUN_COMMAND_EXEC) {
	if (IS_RUN_COMMAND_ERR(status)) {
	do_die:
	pr_err("FATAL: unable to run '%s'", argv[0]);
	status = -128;
	}
	exit(-status);
	}
	errno = ENOENT; /* as if we called execvp */

	argv[0] = tmp;
	zfree(&cmd);
	}

	static int run_argv(int argcp, const char **argv)
	{
	/* See if it's an internal command */
	handle_internal_command(argcp, argv);

	/* .. then try the external ones */
	execv_dashed_external(*argv);
	return 0;
	}

	static void pthread__block_sigwinch(void)
	{
	sigset_t set;

	sigemptyset(&set);
	sigaddset(&set, SIGWINCH);
	pthread_sigmask(SIG_BLOCK, &set, NULL);
	}

	void pthread__unblock_sigwinch(void)
	{
	sigset_t set;

	sigemptyset(&set);
	sigaddset(&set, SIGWINCH);
	pthread_sigmask(SIG_UNBLOCK, &set, NULL);
	}

	int main(int argc, const char **argv)
	{
	int err;
	const char *cmd;
	char sbuf[STRERR_BUFSIZE];

	/* libsubcmd init */
	exec_cmd_init("perf", PREFIX, PERF_EXEC_PATH, EXEC_PATH_ENVIRONMENT);
	pager_init(PERF_PAGER_ENVIRONMENT);

	/* The page_size is placed in util object. */
	page_size = sysconf(_SC_PAGE_SIZE);

	cmd = extract_argv0_path(argv[0]);
	if (!cmd)
	cmd = "perf-help";

	srandom(time(NULL));

	err = perf_config(perf_default_config, NULL);
	if (err)
	return err;
	set_buildid_dir(NULL);

	/*
	* "perf-xxxx" is the same as "perf xxxx", but we obviously:
	*
	* - cannot take flags in between the "perf" and the "xxxx".
	* - cannot execute it externally (since it would just do
	* the same thing over again)
	*
	* So we just directly call the internal command handler. If that one
	* fails to handle this, then maybe we just run a renamed perf binary
	* that contains a dash in its name. To handle this scenario, we just
	* fall through and ignore the "xxxx" part of the command string.
	*/
	if (strstarts(cmd, "perf-")) {
	cmd += 5;
	argv[0] = cmd;
	handle_internal_command(argc, argv);
	/*
	* If the command is handled, the above function does not
	* return undo changes and fall through in such a case.
	*/
	cmd -= 5;
	argv[0] = cmd;
	}
	if (strstarts(cmd, "trace")) {
	#if defined(HAVE_LIBAUDIT_SUPPORT) \|\| defined(HAVE_SYSCALL_TABLE_SUPPORT)
	setup_path();
	argv[0] = "trace";
	return cmd_trace(argc, argv);
	#else
	fprintf(stderr,
	"trace command not available: missing audit-libs devel package at build time.\n");
	goto out;
	#endif
	}
	/* Look for flags.. */
	argv++;
	argc--;
	handle_options(&argv, &argc, NULL);
	commit_pager_choice();

	if (argc > 0) {
	if (strstarts(argv[0], "--"))
	argv[0] += 2;
	} else {
	/* The user didn't specify a command; give them help */
	printf("\n usage: %s\n\n", perf_usage_string);
	list_common_cmds_help();
	printf("\n %s\n\n", perf_more_info_string);
	goto out;
	}
	cmd = argv[0];

	test_attr__init();

	/*
	* We use PATH to find perf commands, but we prepend some higher
	* precedence paths: the "--exec-path" option, the PERF_EXEC_PATH
	* environment, and the $(perfexecdir) from the Makefile at build
	* time.
	*/
	setup_path();
	/*
	* Block SIGWINCH notifications so that the thread that wants it can
	* unblock and get syscalls like select interrupted instead of waiting
	* forever while the signal goes to some other non interested thread.
	*/
	pthread__block_sigwinch();

	perf_debug_setup();

	while (1) {
	static int done_help;

	run_argv(&argc, &argv);

	if (errno != ENOENT)
	break;

	if (!done_help) {
	cmd = argv[0] = help_unknown_cmd(cmd);
	done_help = 1;
	} else
	break;
	}

	fprintf(stderr, "Failed to run command '%s': %s\n",
	cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
	out:
	return 1;
	}