builtin-script.c

#include "builtin.h"

#include "perf.h"
#include "util/cache.h"
#include "util/debug.h"
#include "util/exec_cmd.h"
#include "util/header.h"
#include "util/parse-options.h"
#include "util/session.h"
#include "util/tool.h"
#include "util/symbol.h"
#include "util/thread.h"
#include "util/trace-event.h"
#include "util/util.h"
#include "util/evlist.h"
#include "util/evsel.h"
#include "util/sort.h"
#include <linux/bitmap.h>

static char const		*script_name;
static char const		*generate_script_lang;
static bool			debug_mode;
static u64			last_timestamp;
static u64			nr_unordered;
extern const struct option	record_options[];
static bool			no_callchain;
static bool			system_wide;
static const char		*cpu_list;
static DECLARE_BITMAP(cpu_bitmap, MAX_NR_CPUS);

enum perf_output_field {
	PERF_OUTPUT_COMM            = 1U << 0,
	PERF_OUTPUT_TID             = 1U << 1,
	PERF_OUTPUT_PID             = 1U << 2,
	PERF_OUTPUT_TIME            = 1U << 3,
	PERF_OUTPUT_CPU             = 1U << 4,
	PERF_OUTPUT_EVNAME          = 1U << 5,
	PERF_OUTPUT_TRACE           = 1U << 6,
	PERF_OUTPUT_IP              = 1U << 7,
	PERF_OUTPUT_SYM             = 1U << 8,
	PERF_OUTPUT_DSO             = 1U << 9,
	PERF_OUTPUT_ADDR            = 1U << 10,
	PERF_OUTPUT_SYMOFFSET       = 1U << 11,
};

struct output_option {
	const char *str;
	enum perf_output_field field;
} all_output_options[] = {
	{.str = "comm",  .field = PERF_OUTPUT_COMM},
	{.str = "tid",   .field = PERF_OUTPUT_TID},
	{.str = "pid",   .field = PERF_OUTPUT_PID},
	{.str = "time",  .field = PERF_OUTPUT_TIME},
	{.str = "cpu",   .field = PERF_OUTPUT_CPU},
	{.str = "event", .field = PERF_OUTPUT_EVNAME},
	{.str = "trace", .field = PERF_OUTPUT_TRACE},
	{.str = "ip",    .field = PERF_OUTPUT_IP},
	{.str = "sym",   .field = PERF_OUTPUT_SYM},
	{.str = "dso",   .field = PERF_OUTPUT_DSO},
	{.str = "addr",  .field = PERF_OUTPUT_ADDR},
	{.str = "symoff", .field = PERF_OUTPUT_SYMOFFSET},
};

/* default set to maintain compatibility with current format */
static struct {
	bool user_set;
	bool wildcard_set;
	u64 fields;
	u64 invalid_fields;
} output[PERF_TYPE_MAX] = {

	[PERF_TYPE_HARDWARE] = {
		.user_set = false,

		.fields = PERF_OUTPUT_COMM | PERF_OUTPUT_TID |
			      PERF_OUTPUT_CPU | PERF_OUTPUT_TIME |
			      PERF_OUTPUT_EVNAME | PERF_OUTPUT_IP |
				  PERF_OUTPUT_SYM | PERF_OUTPUT_DSO,

		.invalid_fields = PERF_OUTPUT_TRACE,
	},

	[PERF_TYPE_SOFTWARE] = {
		.user_set = false,

		.fields = PERF_OUTPUT_COMM | PERF_OUTPUT_TID |
			      PERF_OUTPUT_CPU | PERF_OUTPUT_TIME |
			      PERF_OUTPUT_EVNAME | PERF_OUTPUT_IP |
				  PERF_OUTPUT_SYM | PERF_OUTPUT_DSO,

		.invalid_fields = PERF_OUTPUT_TRACE,
	},

	[PERF_TYPE_TRACEPOINT] = {
		.user_set = false,

		.fields = PERF_OUTPUT_COMM | PERF_OUTPUT_TID |
				  PERF_OUTPUT_CPU | PERF_OUTPUT_TIME |
				  PERF_OUTPUT_EVNAME | PERF_OUTPUT_TRACE,
	},

	[PERF_TYPE_RAW] = {
		.user_set = false,

		.fields = PERF_OUTPUT_COMM | PERF_OUTPUT_TID |
			      PERF_OUTPUT_CPU | PERF_OUTPUT_TIME |
			      PERF_OUTPUT_EVNAME | PERF_OUTPUT_IP |
				  PERF_OUTPUT_SYM | PERF_OUTPUT_DSO,

		.invalid_fields = PERF_OUTPUT_TRACE,
	},
};

static bool output_set_by_user(void)
{
	int j;
	for (j = 0; j < PERF_TYPE_MAX; ++j) {
		if (output[j].user_set)
			return true;
	}
	return false;
}

static const char *output_field2str(enum perf_output_field field)
{
	int i, imax = ARRAY_SIZE(all_output_options);
	const char *str = "";

	for (i = 0; i < imax; ++i) {
		if (all_output_options[i].field == field) {
			str = all_output_options[i].str;
			break;
		}
	}
	return str;
}

#define PRINT_FIELD(x)  (output[attr->type].fields & PERF_OUTPUT_##x)

static int perf_evsel__check_stype(struct perf_evsel *evsel,
				   u64 sample_type, const char *sample_msg,
				   enum perf_output_field field)
{
	struct perf_event_attr *attr = &evsel->attr;
	int type = attr->type;
	const char *evname;

	if (attr->sample_type & sample_type)
		return 0;

	if (output[type].user_set) {
		evname = perf_evsel__name(evsel);
		pr_err("Samples for '%s' event do not have %s attribute set. "
		       "Cannot print '%s' field.\n",
		       evname, sample_msg, output_field2str(field));
		return -1;
	}

	/* user did not ask for it explicitly so remove from the default list */
	output[type].fields &= ~field;
	evname = perf_evsel__name(evsel);
	pr_debug("Samples for '%s' event do not have %s attribute set. "
		 "Skipping '%s' field.\n",
		 evname, sample_msg, output_field2str(field));

	return 0;
}

static int perf_evsel__check_attr(struct perf_evsel *evsel,
				  struct perf_session *session)
{
	struct perf_event_attr *attr = &evsel->attr;

	if (PRINT_FIELD(TRACE) &&
		!perf_session__has_traces(session, "record -R"))
		return -EINVAL;

	if (PRINT_FIELD(IP)) {
		if (perf_evsel__check_stype(evsel, PERF_SAMPLE_IP, "IP",
					    PERF_OUTPUT_IP))
			return -EINVAL;

		if (!no_callchain &&
		    !(attr->sample_type & PERF_SAMPLE_CALLCHAIN))
			symbol_conf.use_callchain = false;
	}

	if (PRINT_FIELD(ADDR) &&
		perf_evsel__check_stype(evsel, PERF_SAMPLE_ADDR, "ADDR",
					PERF_OUTPUT_ADDR))
		return -EINVAL;

	if (PRINT_FIELD(SYM) && !PRINT_FIELD(IP) && !PRINT_FIELD(ADDR)) {
		pr_err("Display of symbols requested but neither sample IP nor "
			   "sample address\nis selected. Hence, no addresses to convert "
		       "to symbols.\n");
		return -EINVAL;
	}
	if (PRINT_FIELD(SYMOFFSET) && !PRINT_FIELD(SYM)) {
		pr_err("Display of offsets requested but symbol is not"
		       "selected.\n");
		return -EINVAL;
	}
	if (PRINT_FIELD(DSO) && !PRINT_FIELD(IP) && !PRINT_FIELD(ADDR)) {
		pr_err("Display of DSO requested but neither sample IP nor "
			   "sample address\nis selected. Hence, no addresses to convert "
		       "to DSO.\n");
		return -EINVAL;
	}

	if ((PRINT_FIELD(PID) || PRINT_FIELD(TID)) &&
		perf_evsel__check_stype(evsel, PERF_SAMPLE_TID, "TID",
					PERF_OUTPUT_TID|PERF_OUTPUT_PID))
		return -EINVAL;

	if (PRINT_FIELD(TIME) &&
		perf_evsel__check_stype(evsel, PERF_SAMPLE_TIME, "TIME",
					PERF_OUTPUT_TIME))
		return -EINVAL;

	if (PRINT_FIELD(CPU) &&
		perf_evsel__check_stype(evsel, PERF_SAMPLE_CPU, "CPU",
					PERF_OUTPUT_CPU))
		return -EINVAL;

	return 0;
}

/*
 * verify all user requested events exist and the samples
 * have the expected data
 */
static int perf_session__check_output_opt(struct perf_session *session)
{
	int j;
	struct perf_evsel *evsel;

	for (j = 0; j < PERF_TYPE_MAX; ++j) {
		evsel = perf_session__find_first_evtype(session, j);

		/*
		 * even if fields is set to 0 (ie., show nothing) event must
		 * exist if user explicitly includes it on the command line
		 */
		if (!evsel && output[j].user_set && !output[j].wildcard_set) {
			pr_err("%s events do not exist. "
			       "Remove corresponding -f option to proceed.\n",
			       event_type(j));
			return -1;
		}

		if (evsel && output[j].fields &&
			perf_evsel__check_attr(evsel, session))
			return -1;
	}

	return 0;
}

static void print_sample_start(struct perf_sample *sample,
			       struct thread *thread,
			       struct perf_evsel *evsel)
{
	struct perf_event_attr *attr = &evsel->attr;
	const char *evname = NULL;
	unsigned long secs;
	unsigned long usecs;
	unsigned long long nsecs;

	if (PRINT_FIELD(COMM)) {
		if (latency_format)
			printf("%8.8s ", thread->comm);
		else if (PRINT_FIELD(IP) && symbol_conf.use_callchain)
			printf("%s ", thread->comm);
		else
			printf("%16s ", thread->comm);
	}

	if (PRINT_FIELD(PID) && PRINT_FIELD(TID))
		printf("%5d/%-5d ", sample->pid, sample->tid);
	else if (PRINT_FIELD(PID))
		printf("%5d ", sample->pid);
	else if (PRINT_FIELD(TID))
		printf("%5d ", sample->tid);

	if (PRINT_FIELD(CPU)) {
		if (latency_format)
			printf("%3d ", sample->cpu);
		else
			printf("[%03d] ", sample->cpu);
	}

	if (PRINT_FIELD(TIME)) {
		nsecs = sample->time;
		secs = nsecs / NSECS_PER_SEC;
		nsecs -= secs * NSECS_PER_SEC;
		usecs = nsecs / NSECS_PER_USEC;
		printf("%5lu.%06lu: ", secs, usecs);
	}

	if (PRINT_FIELD(EVNAME)) {
		evname = perf_evsel__name(evsel);
		printf("%s: ", evname ? evname : "[unknown]");
	}
}

static bool is_bts_event(struct perf_event_attr *attr)
{
	return ((attr->type == PERF_TYPE_HARDWARE) &&
		(attr->config & PERF_COUNT_HW_BRANCH_INSTRUCTIONS) &&
		(attr->sample_period == 1));
}

static bool sample_addr_correlates_sym(struct perf_event_attr *attr)
{
	if ((attr->type == PERF_TYPE_SOFTWARE) &&
	    ((attr->config == PERF_COUNT_SW_PAGE_FAULTS) ||
	     (attr->config == PERF_COUNT_SW_PAGE_FAULTS_MIN) ||
	     (attr->config == PERF_COUNT_SW_PAGE_FAULTS_MAJ)))
		return true;

	if (is_bts_event(attr))
		return true;

	return false;
}

static void print_sample_addr(union perf_event *event,
			  struct perf_sample *sample,
			  struct machine *machine,
			  struct thread *thread,
			  struct perf_event_attr *attr)
{
	struct addr_location al;
	u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;

	printf("%16" PRIx64, sample->addr);

	if (!sample_addr_correlates_sym(attr))
		return;

	thread__find_addr_map(thread, machine, cpumode, MAP__FUNCTION,
			      sample->addr, &al);
	if (!al.map)
		thread__find_addr_map(thread, machine, cpumode, MAP__VARIABLE,
				      sample->addr, &al);

	al.cpu = sample->cpu;
	al.sym = NULL;

	if (al.map)
		al.sym = map__find_symbol(al.map, al.addr, NULL);

	if (PRINT_FIELD(SYM)) {
		printf(" ");
		if (PRINT_FIELD(SYMOFFSET))
			symbol__fprintf_symname_offs(al.sym, &al, stdout);
		else
			symbol__fprintf_symname(al.sym, stdout);
	}

	if (PRINT_FIELD(DSO)) {
		printf(" (");
		map__fprintf_dsoname(al.map, stdout);
		printf(")");
	}
}

static void print_sample_bts(union perf_event *event,
			     struct perf_sample *sample,
			     struct perf_evsel *evsel,
			     struct machine *machine,
			     struct thread *thread)
{
	struct perf_event_attr *attr = &evsel->attr;

	/* print branch_from information */
	if (PRINT_FIELD(IP)) {
		if (!symbol_conf.use_callchain)
			printf(" ");
		else
			printf("\n");
		perf_evsel__print_ip(evsel, event, sample, machine,
				     PRINT_FIELD(SYM), PRINT_FIELD(DSO),
				     PRINT_FIELD(SYMOFFSET));
	}

	printf(" => ");

	/* print branch_to information */
	if (PRINT_FIELD(ADDR))
		print_sample_addr(event, sample, machine, thread, attr);

	printf("\n");
}

static void process_event(union perf_event *event, struct perf_sample *sample,
			  struct perf_evsel *evsel, struct machine *machine,
			  struct addr_location *al)
{
	struct perf_event_attr *attr = &evsel->attr;
	struct thread *thread = al->thread;

	if (output[attr->type].fields == 0)
		return;

	print_sample_start(sample, thread, evsel);

	if (is_bts_event(attr)) {
		print_sample_bts(event, sample, evsel, machine, thread);
		return;
	}

	if (PRINT_FIELD(TRACE))
		event_format__print(evsel->tp_format, sample->cpu,
				    sample->raw_data, sample->raw_size);
	if (PRINT_FIELD(ADDR))
		print_sample_addr(event, sample, machine, thread, attr);

	if (PRINT_FIELD(IP)) {
		if (!symbol_conf.use_callchain)
			printf(" ");
		else
			printf("\n");
		perf_evsel__print_ip(evsel, event, sample, machine,
				     PRINT_FIELD(SYM), PRINT_FIELD(DSO),
				     PRINT_FIELD(SYMOFFSET));
	}

	printf("\n");
}

static int default_start_script(const char *script __maybe_unused,
				int argc __maybe_unused,
				const char **argv __maybe_unused)
{
	return 0;
}

static int default_stop_script(void)
{
	return 0;
}

static int default_generate_script(struct pevent *pevent __maybe_unused,
				   const char *outfile __maybe_unused)
{
	return 0;
}

static struct scripting_ops default_scripting_ops = {
	.start_script		= default_start_script,
	.stop_script		= default_stop_script,
	.process_event		= process_event,
	.generate_script	= default_generate_script,
};

static struct scripting_ops	*scripting_ops;

static void setup_scripting(void)
{
	setup_perl_scripting();
	setup_python_scripting();

	scripting_ops = &default_scripting_ops;
}

static int cleanup_scripting(void)
{
	pr_debug("\nperf script stopped\n");

	return scripting_ops->stop_script();
}

static int process_sample_event(struct perf_tool *tool __maybe_unused,
				union perf_event *event,
				struct perf_sample *sample,
				struct perf_evsel *evsel,
				struct machine *machine)
{
	struct addr_location al;
	struct thread *thread = machine__findnew_thread(machine, event->ip.tid);

	if (thread == NULL) {
		pr_debug("problem processing %d event, skipping it.\n",
			 event->header.type);
		return -1;
	}

	if (debug_mode) {
		if (sample->time < last_timestamp) {
			pr_err("Samples misordered, previous: %" PRIu64
				" this: %" PRIu64 "\n", last_timestamp,
				sample->time);
			nr_unordered++;
		}
		last_timestamp = sample->time;
		return 0;
	}

	if (perf_event__preprocess_sample(event, machine, &al, sample, 0) < 0) {
		pr_err("problem processing %d event, skipping it.\n",
		       event->header.type);
		return -1;
	}

	if (al.filtered)
		return 0;

	if (cpu_list && !test_bit(sample->cpu, cpu_bitmap))
		return 0;

	scripting_ops->process_event(event, sample, evsel, machine, &al);

	evsel->hists.stats.total_period += sample->period;
	return 0;
}

static struct perf_tool perf_script = {
	.sample		 = process_sample_event,
	.mmap		 = perf_event__process_mmap,
	.comm		 = perf_event__process_comm,
	.exit		 = perf_event__process_exit,
	.fork		 = perf_event__process_fork,
	.attr		 = perf_event__process_attr,
	.event_type	 = perf_event__process_event_type,
	.tracing_data	 = perf_event__process_tracing_data,
	.build_id	 = perf_event__process_build_id,
	.ordered_samples = true,
	.ordering_requires_timestamps = true,
};

extern volatile int session_done;

static void sig_handler(int sig __maybe_unused)
{
	session_done = 1;
}

static int __cmd_script(struct perf_session *session)
{
	int ret;

	signal(SIGINT, sig_handler);

	ret = perf_session__process_events(session, &perf_script);

	if (debug_mode)
		pr_err("Misordered timestamps: %" PRIu64 "\n", nr_unordered);

	return ret;
}

struct script_spec {
	struct list_head	node;
	struct scripting_ops	*ops;
	char			spec[0];
};

static LIST_HEAD(script_specs);

static struct script_spec *script_spec__new(const char *spec,
					    struct scripting_ops *ops)
{
	struct script_spec *s = malloc(sizeof(*s) + strlen(spec) + 1);

	if (s != NULL) {
		strcpy(s->spec, spec);
		s->ops = ops;
	}

	return s;
}

static void script_spec__add(struct script_spec *s)
{
	list_add_tail(&s->node, &script_specs);
}

static struct script_spec *script_spec__find(const char *spec)
{
	struct script_spec *s;

	list_for_each_entry(s, &script_specs, node)
		if (strcasecmp(s->spec, spec) == 0)
			return s;
	return NULL;
}

static struct script_spec *script_spec__findnew(const char *spec,
						struct scripting_ops *ops)
{
	struct script_spec *s = script_spec__find(spec);

	if (s)
		return s;

	s = script_spec__new(spec, ops);
	if (!s)
		return NULL;

	script_spec__add(s);

	return s;
}

int script_spec_register(const char *spec, struct scripting_ops *ops)
{
	struct script_spec *s;

	s = script_spec__find(spec);
	if (s)
		return -1;

	s = script_spec__findnew(spec, ops);
	if (!s)
		return -1;

	return 0;
}

static struct scripting_ops *script_spec__lookup(const char *spec)
{
	struct script_spec *s = script_spec__find(spec);
	if (!s)
		return NULL;

	return s->ops;
}

static void list_available_languages(void)
{
	struct script_spec *s;

	fprintf(stderr, "\n");
	fprintf(stderr, "Scripting language extensions (used in "
		"perf script -s [spec:]script.[spec]):\n\n");

	list_for_each_entry(s, &script_specs, node)
		fprintf(stderr, "  %-42s [%s]\n", s->spec, s->ops->name);

	fprintf(stderr, "\n");
}

static int parse_scriptname(const struct option *opt __maybe_unused,
			    const char *str, int unset __maybe_unused)
{
	char spec[PATH_MAX];
	const char *script, *ext;
	int len;

	if (strcmp(str, "lang") == 0) {
		list_available_languages();
		exit(0);
	}

	script = strchr(str, ':');
	if (script) {
		len = script - str;
		if (len >= PATH_MAX) {
			fprintf(stderr, "invalid language specifier");
			return -1;
		}
		strncpy(spec, str, len);
		spec[len] = '\0';
		scripting_ops = script_spec__lookup(spec);
		if (!scripting_ops) {
			fprintf(stderr, "invalid language specifier");
			return -1;
		}
		script++;
	} else {
		script = str;
		ext = strrchr(script, '.');
		if (!ext) {
			fprintf(stderr, "invalid script extension");
			return -1;
		}
		scripting_ops = script_spec__lookup(++ext);
		if (!scripting_ops) {
			fprintf(stderr, "invalid script extension");
			return -1;
		}
	}

	script_name = strdup(script);

	return 0;
}

static int parse_output_fields(const struct option *opt __maybe_unused,
			    const char *arg, int unset __maybe_unused)
{
	char *tok;
	int i, imax = ARRAY_SIZE(all_output_options);
	int j;
	int rc = 0;
	char *str = strdup(arg);
	int type = -1;

	if (!str)
		return -ENOMEM;

	/* first word can state for which event type the user is specifying
	 * the fields. If no type exists, the specified fields apply to all
	 * event types found in the file minus the invalid fields for a type.
	 */
	tok = strchr(str, ':');
	if (tok) {
		*tok = '\0';
		tok++;
		if (!strcmp(str, "hw"))
			type = PERF_TYPE_HARDWARE;
		else if (!strcmp(str, "sw"))
			type = PERF_TYPE_SOFTWARE;
		else if (!strcmp(str, "trace"))
			type = PERF_TYPE_TRACEPOINT;
		else if (!strcmp(str, "raw"))
			type = PERF_TYPE_RAW;
		else {
			fprintf(stderr, "Invalid event type in field string.\n");
			rc = -EINVAL;
			goto out;
		}

		if (output[type].user_set)
			pr_warning("Overriding previous field request for %s events.\n",
				   event_type(type));

		output[type].fields = 0;
		output[type].user_set = true;
		output[type].wildcard_set = false;

	} else {
		tok = str;
		if (strlen(str) == 0) {
			fprintf(stderr,
				"Cannot set fields to 'none' for all event types.\n");
			rc = -EINVAL;
			goto out;
		}

		if (output_set_by_user())
			pr_warning("Overriding previous field request for all events.\n");

		for (j = 0; j < PERF_TYPE_MAX; ++j) {
			output[j].fields = 0;
			output[j].user_set = true;
			output[j].wildcard_set = true;
		}
	}

	tok = strtok(tok, ",");
	while (tok) {
		for (i = 0; i < imax; ++i) {
			if (strcmp(tok, all_output_options[i].str) == 0)
				break;
		}
		if (i == imax) {
			fprintf(stderr, "Invalid field requested.\n");
			rc = -EINVAL;
			goto out;
		}

		if (type == -1) {
			/* add user option to all events types for
			 * which it is valid
			 */
			for (j = 0; j < PERF_TYPE_MAX; ++j) {
				if (output[j].invalid_fields & all_output_options[i].field) {
					pr_warning("\'%s\' not valid for %s events. Ignoring.\n",
						   all_output_options[i].str, event_type(j));
				} else
					output[j].fields |= all_output_options[i].field;
			}
		} else {
			if (output[type].invalid_fields & all_output_options[i].field) {
				fprintf(stderr, "\'%s\' not valid for %s events.\n",
					 all_output_options[i].str, event_type(type));

				rc = -EINVAL;
				goto out;
			}
			output[type].fields |= all_output_options[i].field;
		}

		tok = strtok(NULL, ",");
	}

	if (type >= 0) {
		if (output[type].fields == 0) {
			pr_debug("No fields requested for %s type. "
				 "Events will not be displayed.\n", event_type(type));
		}
	}

out:
	free(str);
	return rc;
}

/* Helper function for filesystems that return a dent->d_type DT_UNKNOWN */
static int is_directory(const char *base_path, const struct dirent *dent)
{
	char path[PATH_MAX];
	struct stat st;

	sprintf(path, "%s/%s", base_path, dent->d_name);
	if (stat(path, &st))
		return 0;

	return S_ISDIR(st.st_mode);
}

#define for_each_lang(scripts_path, scripts_dir, lang_dirent, lang_next)\
	while (!readdir_r(scripts_dir, &lang_dirent, &lang_next) &&	\
	       lang_next)						\
		if ((lang_dirent.d_type == DT_DIR ||			\
		     (lang_dirent.d_type == DT_UNKNOWN &&		\
		      is_directory(scripts_path, &lang_dirent))) &&	\
		    (strcmp(lang_dirent.d_name, ".")) &&		\
		    (strcmp(lang_dirent.d_name, "..")))

#define for_each_script(lang_path, lang_dir, script_dirent, script_next)\
	while (!readdir_r(lang_dir, &script_dirent, &script_next) &&	\
	       script_next)						\
		if (script_dirent.d_type != DT_DIR &&			\
		    (script_dirent.d_type != DT_UNKNOWN ||		\
		     !is_directory(lang_path, &script_dirent)))


#define RECORD_SUFFIX			"-record"
#define REPORT_SUFFIX			"-report"

struct script_desc {
	struct list_head	node;
	char			*name;
	char			*half_liner;
	char			*args;
};

static LIST_HEAD(script_descs);

static struct script_desc *script_desc__new(const char *name)
{
	struct script_desc *s = zalloc(sizeof(*s));

	if (s != NULL && name)
		s->name = strdup(name);

	return s;
}

static void script_desc__delete(struct script_desc *s)
{
	free(s->name);
	free(s->half_liner);
	free(s->args);
	free(s);
}

static void script_desc__add(struct script_desc *s)
{
	list_add_tail(&s->node, &script_descs);
}

static struct script_desc *script_desc__find(const char *name)
{
	struct script_desc *s;

	list_for_each_entry(s, &script_descs, node)
		if (strcasecmp(s->name, name) == 0)
			return s;
	return NULL;
}

static struct script_desc *script_desc__findnew(const char *name)
{
	struct script_desc *s = script_desc__find(name);

	if (s)
		return s;

	s = script_desc__new(name);
	if (!s)
		goto out_delete_desc;

	script_desc__add(s);

	return s;

out_delete_desc:
	script_desc__delete(s);

	return NULL;
}

static const char *ends_with(const char *str, const char *suffix)
{
	size_t suffix_len = strlen(suffix);
	const char *p = str;

	if (strlen(str) > suffix_len) {
		p = str + strlen(str) - suffix_len;
		if (!strncmp(p, suffix, suffix_len))
			return p;
	}

	return NULL;
}

static int read_script_info(struct script_desc *desc, const char *filename)
{
	char line[BUFSIZ], *p;
	FILE *fp;

	fp = fopen(filename, "r");
	if (!fp)
		return -1;

	while (fgets(line, sizeof(line), fp)) {
		p = ltrim(line);
		if (strlen(p) == 0)
			continue;
		if (*p != '#')
			continue;
		p++;
		if (strlen(p) && *p == '!')
			continue;

		p = ltrim(p);
		if (strlen(p) && p[strlen(p) - 1] == '\n')
			p[strlen(p) - 1] = '\0';

		if (!strncmp(p, "description:", strlen("description:"))) {
			p += strlen("description:");
			desc->half_liner = strdup(ltrim(p));
			continue;
		}

		if (!strncmp(p, "args:", strlen("args:"))) {
			p += strlen("args:");
			desc->args = strdup(ltrim(p));
			continue;
		}
	}

	fclose(fp);

	return 0;
}

static char *get_script_root(struct dirent *script_dirent, const char *suffix)
{
	char *script_root, *str;

	script_root = strdup(script_dirent->d_name);
	if (!script_root)
		return NULL;

	str = (char *)ends_with(script_root, suffix);
	if (!str) {
		free(script_root);
		return NULL;
	}

	*str = '\0';
	return script_root;
}

static int list_available_scripts(const struct option *opt __maybe_unused,
				  const char *s __maybe_unused,
				  int unset __maybe_unused)
{
	struct dirent *script_next, *lang_next, script_dirent, lang_dirent;
	char scripts_path[MAXPATHLEN];
	DIR *scripts_dir, *lang_dir;
	char script_path[MAXPATHLEN];
	char lang_path[MAXPATHLEN];
	struct script_desc *desc;
	char first_half[BUFSIZ];
	char *script_root;

	snprintf(scripts_path, MAXPATHLEN, "%s/scripts", perf_exec_path());

	scripts_dir = opendir(scripts_path);
	if (!scripts_dir)
		return -1;

	for_each_lang(scripts_path, scripts_dir, lang_dirent, lang_next) {
		snprintf(lang_path, MAXPATHLEN, "%s/%s/bin", scripts_path,
			 lang_dirent.d_name);
		lang_dir = opendir(lang_path);
		if (!lang_dir)
			continue;

		for_each_script(lang_path, lang_dir, script_dirent, script_next) {
			script_root = get_script_root(&script_dirent, REPORT_SUFFIX);
			if (script_root) {
				desc = script_desc__findnew(script_root);