#include <linux/list.h>
#include <linux/compiler.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdbool.h>
#include <stdarg.h>
#include <dirent.h>
#include <api/fs/fs.h>
#include <locale.h>
#include "util.h"
#include "pmu.h"
#include "parse-events.h"
#include "cpumap.h"

struct perf_pmu_format {
        char *name;
        int value;
        DECLARE_BITMAP(bits, PERF_PMU_FORMAT_BITS);
        struct list_head list;
};

#define EVENT_SOURCE_DEVICE_PATH "/bus/event_source/devices/"

int perf_pmu_parse(struct list_head *list, char *name);
extern FILE *perf_pmu_in;

static LIST_HEAD(pmus);

/*
 * Parse & process all the sysfs attributes located under
 * the directory specified in 'dir' parameter.
 */
int perf_pmu__format_parse(char *dir, struct list_head *head)
{
        struct dirent *evt_ent;
        DIR *format_dir;
        int ret = 0;

        format_dir = opendir(dir);
        if (!format_dir)
                return -EINVAL;

        while (!ret && (evt_ent = readdir(format_dir))) {
                char path[PATH_MAX];
                char *name = evt_ent->d_name;
                FILE *file;

                if (!strcmp(name, ".") || !strcmp(name, ".."))
                        continue;

                snprintf(path, PATH_MAX, "%s/%s", dir, name);

                ret = -EINVAL;
                file = fopen(path, "r");
                if (!file)
                        break;

                perf_pmu_in = file;
                ret = perf_pmu_parse(head, name);
                fclose(file);
        }

        closedir(format_dir);
        return ret;
}

/*
 * Reading/parsing the default pmu format definition, which should be
 * located at:
 * /sys/bus/event_source/devices/<dev>/format as sysfs group attributes.
 */
static int pmu_format(const char *name, struct list_head *format)
{
        struct stat st;
        char path[PATH_MAX];
        const char *sysfs = sysfs__mountpoint();

        if (!sysfs)
                return -1;

        snprintf(path, PATH_MAX,
                 "%s" EVENT_SOURCE_DEVICE_PATH "%s/format", sysfs, name);

        if (stat(path, &st) < 0)
                return 0;       /* no error if format does not exist */

        if (perf_pmu__format_parse(path, format))
                return -1;

        return 0;
}

static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, char *dir, char *name)
{
        struct stat st;
        ssize_t sret;
        char scale[128];
        int fd, ret = -1;
        char path[PATH_MAX];
        char *lc;

        snprintf(path, PATH_MAX, "%s/%s.scale", dir, name);

        fd = open(path, O_RDONLY);
        if (fd == -1)
                return -1;

        if (fstat(fd, &st) < 0)
                goto error;

        sret = read(fd, scale, sizeof(scale)-1);
        if (sret < 0)
                goto error;

        if (scale[sret - 1] == '\n')
                scale[sret - 1] = '\0';
        else
                scale[sret] = '\0';

        /*
         * save current locale
         */
        lc = setlocale(LC_NUMERIC, NULL);

        /*
         * The lc string may be allocated in static storage,
         * so get a dynamic copy to make it survive setlocale
         * call below.
         */
        lc = strdup(lc);
        if (!lc) {
                ret = -ENOMEM;
                goto error;
        }

        /*
         * force to C locale to ensure kernel
         * scale string is converted correctly.
         * kernel uses default C locale.
         */
        setlocale(LC_NUMERIC, "C");

        alias->scale = strtod(scale, NULL);

        /* restore locale */
        setlocale(LC_NUMERIC, lc);

        free(lc);

        ret = 0;
error:
        close(fd);
        return ret;
}

static int perf_pmu__parse_unit(struct perf_pmu_alias *alias, char *dir, char *name)
{
        char path[PATH_MAX];
        ssize_t sret;
        int fd;

        snprintf(path, PATH_MAX, "%s/%s.unit", dir, name);

        fd = open(path, O_RDONLY);
        if (fd == -1)
                return -1;

        sret = read(fd, alias->unit, UNIT_MAX_LEN);
        if (sret < 0)
                goto error;

        close(fd);

        if (alias->unit[sret - 1] == '\n')
                alias->unit[sret - 1] = '\0';
        else
                alias->unit[sret] = '\0';

        return 0;
error:
        close(fd);
        alias->unit[0] = '\0';
        return -1;
}

static int
perf_pmu__parse_per_pkg(struct perf_pmu_alias *alias, char *dir, char *name)
{
        char path[PATH_MAX];
        int fd;

        snprintf(path, PATH_MAX, "%s/%s.per-pkg", dir, name);

        fd = open(path, O_RDONLY);
        if (fd == -1)
                return -1;

        close(fd);

        alias->per_pkg = true;
        return 0;
}

static int perf_pmu__parse_snapshot(struct perf_pmu_alias *alias,
                                    char *dir, char *name)
{
        char path[PATH_MAX];
        int fd;

        snprintf(path, PATH_MAX, "%s/%s.snapshot", dir, name);

        fd = open(path, O_RDONLY);
        if (fd == -1)
                return -1;

        alias->snapshot = true;
        close(fd);
        return 0;
}

static int __perf_pmu__new_alias(struct list_head *list, char *dir, char *name,
                                 char *desc __maybe_unused, char *val)
{
        struct perf_pmu_alias *alias;
        int ret;

        alias = malloc(sizeof(*alias));
        if (!alias)
                return -ENOMEM;

        INIT_LIST_HEAD(&alias->terms);
        alias->scale = 1.0;
        alias->unit[0] = '\0';
        alias->per_pkg = false;
        alias->snapshot = false;

        ret = parse_events_terms(&alias->terms, val);
        if (ret) {
                pr_err("Cannot parse alias %s: %d\n", val, ret);
                free(alias);
                return ret;
        }

        alias->name = strdup(name);
        if (dir) {
                /*
                 * load unit name and scale if available
                 */
                perf_pmu__parse_unit(alias, dir, name);
                perf_pmu__parse_scale(alias, dir, name);
                perf_pmu__parse_per_pkg(alias, dir, name);
                perf_pmu__parse_snapshot(alias, dir, name);
        }

        list_add_tail(&alias->list, list);

        return 0;
}

static int perf_pmu__new_alias(struct list_head *list, char *dir, char *name, FILE *file)
{
        char buf[256];
        int ret;

        ret = fread(buf, 1, sizeof(buf), file);
        if (ret == 0)
                return -EINVAL;

        buf[ret] = 0;

        return __perf_pmu__new_alias(list, dir, name, NULL, buf);
}

static inline bool pmu_alias_info_file(char *name)
{
        size_t len;

        len = strlen(name);
        if (len > 5 && !strcmp(name + len - 5, ".unit"))
                return true;
        if (len > 6 && !strcmp(name + len - 6, ".scale"))
                return true;
        if (len > 8 && !strcmp(name + len - 8, ".per-pkg"))
                return true;
        if (len > 9 && !strcmp(name + len - 9, ".snapshot"))
                return true;

        return false;
}

/*
 * Process all the sysfs attributes located under the directory
 * specified in 'dir' parameter.
 */
static int pmu_aliases_parse(char *dir, struct list_head *head)
{
        struct dirent *evt_ent;
        DIR *event_dir;

        event_dir = opendir(dir);
        if (!event_dir)
                return -EINVAL;

        while ((evt_ent = readdir(event_dir))) {
                char path[PATH_MAX];
                char *name = evt_ent->d_name;
                FILE *file;

                if (!strcmp(name, ".") || !strcmp(name, ".."))
                        continue;

                /*
                 * skip info files parsed in perf_pmu__new_alias()
                 */
                if (pmu_alias_info_file(name))
                        continue;

                snprintf(path, PATH_MAX, "%s/%s", dir, name);

                file = fopen(path, "r");
                if (!file) {
                        pr_debug("Cannot open %s\n", path);
                        continue;
                }

                if (perf_pmu__new_alias(head, dir, name, file) < 0)
                        pr_debug("Cannot set up %s\n", name);
                fclose(file);
        }

        closedir(event_dir);
        return 0;
}

/*
 * Reading the pmu event aliases definition, which should be located at:
 * /sys/bus/event_source/devices/<dev>/events as sysfs group attributes.
 */
static int pmu_aliases(const char *name, struct list_head *head)
{
        struct stat st;
        char path[PATH_MAX];
        const char *sysfs = sysfs__mountpoint();

        if (!sysfs)
                return -1;

        snprintf(path, PATH_MAX,
                 "%s/bus/event_source/devices/%s/events", sysfs, name);

        if (stat(path, &st) < 0)
                return 0;        /* no error if 'events' does not exist */

        if (pmu_aliases_parse(path, head))
                return -1;

        return 0;
}

static int pmu_alias_terms(struct perf_pmu_alias *alias,
                           struct list_head *terms)
{
        struct parse_events_term *term, *cloned;
        LIST_HEAD(list);
        int ret;

        list_for_each_entry(term, &alias->terms, list) {
                ret = parse_events_term__clone(&cloned, term);
                if (ret) {
                        parse_events_terms__purge(&list);
                        return ret;
                }
                list_add_tail(&cloned->list, &list);
        }
        list_splice(&list, terms);
        return 0;
}

/*
 * Reading/parsing the default pmu type value, which should be
 * located at:
 * /sys/bus/event_source/devices/<dev>/type as sysfs attribute.
 */
static int pmu_type(const char *name, __u32 *type)
{
        struct stat st;
        char path[PATH_MAX];
        FILE *file;
        int ret = 0;
        const char *sysfs = sysfs__mountpoint();

        if (!sysfs)
                return -1;

        snprintf(path, PATH_MAX,
                 "%s" EVENT_SOURCE_DEVICE_PATH "%s/type", sysfs, name);

        if (stat(path, &st) < 0)
                return -1;

        file = fopen(path, "r");
        if (!file)
                return -EINVAL;

        if (1 != fscanf(file, "%u", type))
                ret = -1;

        fclose(file);
        return ret;
}

/* Add all pmus in sysfs to pmu list: */
static void pmu_read_sysfs(void)
{
        char path[PATH_MAX];
        DIR *dir;
        struct dirent *dent;
        const char *sysfs = sysfs__mountpoint();

        if (!sysfs)
                return;

        snprintf(path, PATH_MAX,
                 "%s" EVENT_SOURCE_DEVICE_PATH, sysfs);

        dir = opendir(path);
        if (!dir)
                return;

        while ((dent = readdir(dir))) {
                if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
                        continue;
                /* add to static LIST_HEAD(pmus): */
                perf_pmu__find(dent->d_name);
        }

        closedir(dir);
}

static struct cpu_map *pmu_cpumask(const char *name)
{
        struct stat st;
        char path[PATH_MAX];
        FILE *file;
        struct cpu_map *cpus;
        const char *sysfs = sysfs__mountpoint();

        if (!sysfs)
                return NULL;

        snprintf(path, PATH_MAX,
                 "%s/bus/event_source/devices/%s/cpumask", sysfs, name);

        if (stat(path, &st) < 0)
                return NULL;

        file = fopen(path, "r");
        if (!file)
                return NULL;

        cpus = cpu_map__read(file);
        fclose(file);
        return cpus;
}

struct perf_event_attr * __weak
perf_pmu__get_default_config(struct perf_pmu *pmu __maybe_unused)
{
        return NULL;
}

static struct perf_pmu *pmu_lookup(const char *name)
{
        struct perf_pmu *pmu;
        LIST_HEAD(format);
        LIST_HEAD(aliases);
        __u32 type;

        /*
         * The pmu data we store & need consists of the pmu
         * type value and format definitions. Load both right
         * now.
         */
        if (pmu_format(name, &format))
                return NULL;

        if (pmu_aliases(name, &aliases))
                return NULL;

        if (pmu_type(name, &type))
                return NULL;

        pmu = zalloc(sizeof(*pmu));
        if (!pmu)
                return NULL;

        pmu->cpus = pmu_cpumask(name);

        INIT_LIST_HEAD(&pmu->format);
        INIT_LIST_HEAD(&pmu->aliases);
        list_splice(&format, &pmu->format);
        list_splice(&aliases, &pmu->aliases);
        pmu->name = strdup(name);
        pmu->type = type;
        list_add_tail(&pmu->list, &pmus);

        pmu->default_config = perf_pmu__get_default_config(pmu);

        return pmu;
}

static struct perf_pmu *pmu_find(const char *name)
{
        struct perf_pmu *pmu;

        list_for_each_entry(pmu, &pmus, list)
                if (!strcmp(pmu->name, name))
                        return pmu;

        return NULL;
}

struct perf_pmu *perf_pmu__scan(struct perf_pmu *pmu)
{
        /*
         * pmu iterator: If pmu is NULL, we start at the begin,
         * otherwise return the next pmu. Returns NULL on end.
         */
        if (!pmu) {
                pmu_read_sysfs();
                pmu = list_prepare_entry(pmu, &pmus, list);
        }
        list_for_each_entry_continue(pmu, &pmus, list)
                return pmu;
        return NULL;
}

struct perf_pmu *perf_pmu__find(const char *name)
{
        struct perf_pmu *pmu;

        /*
         * Once PMU is loaded it stays in the list,
         * so we keep us from multiple reading/parsing
         * the pmu format definitions.
         */
        pmu = pmu_find(name);
        if (pmu)
                return pmu;

        return pmu_lookup(name);
}

static struct perf_pmu_format *
pmu_find_format(struct list_head *formats, const char *name)
{
        struct perf_pmu_format *format;

        list_for_each_entry(format, formats, list)
                if (!strcmp(format->name, name))
                        return format;

        return NULL;
}

__u64 perf_pmu__format_bits(struct list_head *formats, const char *name)
{
        struct perf_pmu_format *format = pmu_find_format(formats, name);
        __u64 bits = 0;
        int fbit;

        if (!format)
                return 0;

        for_each_set_bit(fbit, format->bits, PERF_PMU_FORMAT_BITS)
                bits |= 1ULL << fbit;

        return bits;
}

/*
 * Sets value based on the format definition (format parameter)
 * and unformated value (value parameter).
 */
static void pmu_format_value(unsigned long *format, __u64 value, __u64 *v,
                             bool zero)
{
        unsigned long fbit, vbit;

        for (fbit = 0, vbit = 0; fbit < PERF_PMU_FORMAT_BITS; fbit++) {

                if (!test_bit(fbit, format))
                        continue;

                if (value & (1llu << vbit++))
                        *v |= (1llu << fbit);
                else if (zero)
                        *v &= ~(1llu << fbit);
        }
}

static __u64 pmu_format_max_value(const unsigned long *format)
{
        int w;

        w = bitmap_weight(format, PERF_PMU_FORMAT_BITS);
        if (!w)
                return 0;
        if (w < 64)
                return (1ULL << w) - 1;
        return -1;
}

/*
 * Term is a string term, and might be a param-term. Try to look up it's value
 * in the remaining terms.
 * - We have a term like "base-or-format-term=param-term",
 * - We need to find the value supplied for "param-term" (with param-term named
 *   in a config string) later on in the term list.
 */
static int pmu_resolve_param_term(struct parse_events_term *term,
                                  struct list_head *head_terms,
                                  __u64 *value)
{
        struct parse_events_term *t;

        list_for_each_entry(t, head_terms, list) {
                if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
                        if (!strcmp(t->config, term->config)) {
                                t->used = true;
                                *value = t->val.num;
                                return 0;
                        }
                }
        }

        if (verbose)
                printf("Required parameter '%s' not specified\n", term->config);

        return -1;
}

static char *pmu_formats_string(struct list_head *formats)
{
        struct perf_pmu_format *format;
        char *str;
        struct strbuf buf;
        unsigned i = 0;

        if (!formats)
                return NULL;

        strbuf_init(&buf, 0);
        /* sysfs exported terms */
        list_for_each_entry(format, formats, list)
                strbuf_addf(&buf, i++ ? ",%s" : "%s",
                            format->name);

        str = strbuf_detach(&buf, NULL);
        strbuf_release(&buf);

        return str;
}

/*
 * Setup one of config[12] attr members based on the
 * user input data - term parameter.
 */
static int pmu_config_term(struct list_head *formats,
                           struct perf_event_attr *attr,
                           struct parse_events_term *term,
                           struct list_head *head_terms,
                           bool zero, struct parse_events_error *err)
{
        struct perf_pmu_format *format;
        __u64 *vp;
        __u64 val, max_val;

        /*
         * If this is a parameter we've already used for parameterized-eval,
         * skip it in normal eval.
         */
        if (term->used)
                return 0;

        /*
         * Hardcoded terms should be already in, so nothing
         * to be done for them.
         */
        if (parse_events__is_hardcoded_term(term))
                return 0;

        format = pmu_find_format(formats, term->config);
        if (!format) {
                if (verbose)
                        printf("Invalid event/parameter '%s'\n", term->config);
                if (err) {
                        char *pmu_term = pmu_formats_string(formats);

                        err->idx  = term->err_term;
                        err->str  = strdup("unknown term");
                        err->help = parse_events_formats_error_string(pmu_term);
                        free(pmu_term);
                }
                return -EINVAL;
        }

        switch (format->value) {
        case PERF_PMU_FORMAT_VALUE_CONFIG:
                vp = &attr->config;
                break;
        case PERF_PMU_FORMAT_VALUE_CONFIG1:
                vp = &attr->config1;
                break;
        case PERF_PMU_FORMAT_VALUE_CONFIG2:
                vp = &attr->config2;
                break;
        default:
                return -EINVAL;
        }

        /*
         * Either directly use a numeric term, or try to translate string terms
         * using event parameters.
         */
        if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
                val = term->val.num;
        else if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR) {
                if (strcmp(term->val.str, "?")) {
                        if (verbose) {
                                pr_info("Invalid sysfs entry %s=%s\n",
                                                term->config, term->val.str);
                        }
                        if (err) {
                                err->idx = term->err_val;
                                err->str = strdup("expected numeric value");
                        }
                        return -EINVAL;
                }

                if (pmu_resolve_param_term(term, head_terms, &val))
                        return -EINVAL;
        } else
                return -EINVAL;

        max_val = pmu_format_max_value(format->bits);
        if (val > max_val) {
                if (err) {
                        err->idx = term->err_val;
                        if (asprintf(&err->str,
                                     "value too big for format, maximum is %llu",
                                     (unsigned long long)max_val) < 0)
                                err->str = strdup("value too big for format");
                        return -EINVAL;
                }
                /*
                 * Assume we don't care if !err, in which case the value will be
                 * silently truncated.
                 */
        }

        pmu_format_value(format->bits, val, vp, zero);
        return 0;
}

int perf_pmu__config_terms(struct list_head *formats,
                           struct perf_event_attr *attr,
                           struct list_head *head_terms,
                           bool zero, struct parse_events_error *err)
{
        struct parse_events_term *term;

        list_for_each_entry(term, head_terms, list) {
                if (pmu_config_term(formats, attr, term, head_terms,
                                    zero, err))
                        return -EINVAL;
        }

        return 0;
}

/*
 * Configures event's 'attr' parameter based on the:
 * 1) users input - specified in terms parameter
 * 2) pmu format definitions - specified by pmu parameter
 */
int perf_pmu__config(struct perf_pmu *pmu, struct perf_event_attr *attr,
                     struct list_head *head_terms,
                     struct parse_events_error *err)
{
        bool zero = !!pmu->default_config;

        attr->type = pmu->type;
        return perf_pmu__config_terms(&pmu->format, attr, head_terms,
                                      zero, err);
}

static struct perf_pmu_alias *pmu_find_alias(struct perf_pmu *pmu,
                                             struct parse_events_term *term)
{
        struct perf_pmu_alias *alias;
        char *name;

        if (parse_events__is_hardcoded_term(term))
                return NULL;

        if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
                if (term->val.num != 1)
                        return NULL;
                if (pmu_find_format(&pmu->format, term->config))
                        return NULL;
                name = term->config;
        } else if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR) {
                if (strcasecmp(term->config, "event"))
                        return NULL;
                name = term->val.str;
        } else {
                return NULL;
        }

        list_for_each_entry(alias, &pmu->aliases, list) {
                if (!strcasecmp(alias->name, name))
                        return alias;
        }
        return NULL;
}


static int check_info_data(struct perf_pmu_alias *alias,
                           struct perf_pmu_info *info)
{
        /*
         * Only one term in event definition can
         * define unit, scale and snapshot, fail
         * if there's more than one.
         */
        if ((info->unit && alias->unit) ||
            (info->scale && alias->scale) ||
            (info->snapshot && alias->snapshot))
                return -EINVAL;

        if (alias->unit)
                info->unit = alias->unit;

        if (alias->scale)
                info->scale = alias->scale;

        if (alias->snapshot)
                info->snapshot = alias->snapshot;

        return 0;
}

/*
 * Find alias in the terms list and replace it with the terms
 * defined for the alias
 */
int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
                          struct perf_pmu_info *info)
{
        struct parse_events_term *term, *h;
        struct perf_pmu_alias *alias;
        int ret;

        info->per_pkg = false;

        /*
         * Mark unit and scale as not set
         * (different from default values, see below)
         */
        info->unit     = NULL;
        info->scale    = 0.0;
        info->snapshot = false;

        list_for_each_entry_safe(term, h, head_terms, list) {
                alias = pmu_find_alias(pmu, term);
                if (!alias)
                        continue;
                ret = pmu_alias_terms(alias, &term->list);
                if (ret)
                        return ret;

                ret = check_info_data(alias, info);
                if (ret)
                        return ret;

                if (alias->per_pkg)
                        info->per_pkg = true;

                list_del(&term->list);
                free(term);
        }

        /*
         * if no unit or scale foundin aliases, then
         * set defaults as for evsel
         * unit cannot left to NULL
         */
        if (info->unit == NULL)
                info->unit   = "";

        if (info->scale == 0.0)
                info->scale  = 1.0;

        return 0;
}

int perf_pmu__new_format(struct list_head *list, char *name,
                         int config, unsigned long *bits)
{
        struct perf_pmu_format *format;

        format = zalloc(sizeof(*format));
        if (!format)
                return -ENOMEM;

        format->name = strdup(name);
        format->value = config;
        memcpy(format->bits, bits, sizeof(format->bits));

        list_add_tail(&format->list, list);
        return 0;
}

void perf_pmu__set_format(unsigned long *bits, long from, long to)
{
        long b;

        if (!to)
                to = from;

        memset(bits, 0, BITS_TO_BYTES(PERF_PMU_FORMAT_BITS));
        for (b = from; b <= to; b++)
                set_bit(b, bits);
}

static int sub_non_neg(int a, int b)
{
        if (b > a)
                return 0;
        return a - b;
}

static char *format_alias(char *buf, int len, struct perf_pmu *pmu,
                          struct perf_pmu_alias *alias)
{
        struct parse_events_term *term;
        int used = snprintf(buf, len, "%s/%s", pmu->name, alias->name);

        list_for_each_entry(term, &alias->terms, list) {
                if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR)
                        used += snprintf(buf + used, sub_non_neg(len, used),
                                        ",%s=%s", term->config,
                                        term->val.str);
        }

        if (sub_non_neg(len, used) > 0) {
                buf[used] = '/';
                used++;
        }
        if (sub_non_neg(len, used) > 0) {
                buf[used] = '\0';
                used++;
        } else
                buf[len - 1] = '\0';

        return buf;
}

static char *format_alias_or(char *buf, int len, struct perf_pmu *pmu,
                             struct perf_pmu_alias *alias)
{
        snprintf(buf, len, "%s OR %s/%s/", alias->name, pmu->name, alias->name);
        return buf;
}

static int cmp_string(const void *a, const void *b)
{
        const char * const *as = a;
        const char * const *bs = b;
        return strcmp(*as, *bs);
}

void print_pmu_events(const char *event_glob, bool name_only)
{
        struct perf_pmu *pmu;
        struct perf_pmu_alias *alias;
        char buf[1024];
        int printed = 0;
        int len, j;
        char **aliases;

        pmu = NULL;
        len = 0;
        while ((pmu = perf_pmu__scan(pmu)) != NULL) {
                list_for_each_entry(alias, &pmu->aliases, list)
                        len++;
                if (pmu->selectable)
                        len++;

        }
        aliases = zalloc(sizeof(char *) * len);
        if (!aliases)
                goto out_enomem;
        pmu = NULL;
        j = 0;
        while ((pmu = perf_pmu__scan(pmu)) != NULL) {
                list_for_each_entry(alias, &pmu->aliases, list) {
                        char *name = format_alias(buf, sizeof(buf), pmu, alias);
                        bool is_cpu = !strcmp(pmu->name, "cpu");

                        if (event_glob != NULL &&
                            !(strglobmatch(name, event_glob) ||
                              (!is_cpu && strglobmatch(alias->name,
                                                       event_glob))))
                                continue;

                        if (is_cpu && !name_only)
                                name = format_alias_or(buf, sizeof(buf), pmu, alias);

                        aliases[j] = strdup(name);
                        if (aliases[j] == NULL)
                                goto out_enomem;
                        j++;
                }
                if (pmu->selectable &&
                    (event_glob == NULL || strglobmatch(pmu->name, event_glob))) {
                        char *s;
                        if (asprintf(&s, "%s//", pmu->name) < 0)
                                goto out_enomem;
                        aliases[j] = s;
                        j++;
                }
        }
        len = j;
        qsort(aliases, len, sizeof(char *), cmp_string);
        for (j = 0; j < len; j++) {
                if (name_only) {
                        printf("%s ", aliases[j]);
                        continue;
                }
                printf("  %-50s [Kernel PMU event]\n", aliases[j]);
                printed++;
        }
        if (printed && pager_in_use())
                printf("\n");
out_free:
        for (j = 0; j < len; j++)
                zfree(&aliases[j]);
        zfree(&aliases);
        return;

out_enomem:
        printf("FATAL: not enough memory to print PMU events\n");
        if (aliases)
                goto out_free;
}

bool pmu_have_event(const char *pname, const char *name)
{
        struct perf_pmu *pmu;
        struct perf_pmu_alias *alias;

        pmu = NULL;
        while ((pmu = perf_pmu__scan(pmu)) != NULL) {
                if (strcmp(pname, pmu->name))
                        continue;
                list_for_each_entry(alias, &pmu->aliases, list)
                        if (!strcmp(alias->name, name))
                                return true;
        }
        return false;
}

static FILE *perf_pmu__open_file(struct perf_pmu *pmu, const char *name)
{
        struct stat st;
        char path[PATH_MAX];
        const char *sysfs;

        sysfs = sysfs__mountpoint();
        if (!sysfs)
                return NULL;

        snprintf(path, PATH_MAX,
                 "%s" EVENT_SOURCE_DEVICE_PATH "%s/%s", sysfs, pmu->name, name);

        if (stat(path, &st) < 0)
                return NULL;

        return fopen(path, "r");
}

int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt,
                        ...)
{
        va_list args;
        FILE *file;
        int ret = EOF;

        va_start(args, fmt);
        file = perf_pmu__open_file(pmu, name);
        if (file) {
                ret = vfscanf(file, fmt, args);
                fclose(file);
        }
        va_end(args);
        return ret;
}