// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2011, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
 *
 * Parts came from builtin-{top,stat,record}.c, see those files for further
 * copyright notes.
 */

#include <byteswap.h>
#include <errno.h>
#include <inttypes.h>
#include <linux/bitops.h>
#include <api/fs/fs.h>
#include <api/fs/tracing_path.h>
#include <traceevent/event-parse.h>
#include <linux/hw_breakpoint.h>
#include <linux/perf_event.h>
#include <linux/compiler.h>
#include <linux/err.h>
#include <linux/zalloc.h>
#include <sys/ioctl.h>
#include <sys/resource.h>
#include <sys/types.h>
#include <dirent.h>
#include <stdlib.h>
#include <perf/evsel.h>
#include "asm/bug.h"
#include "callchain.h"
#include "cgroup.h"
#include "counts.h"
#include "event.h"
#include "evsel.h"
#include "util/env.h"
#include "util/evsel_config.h"
#include "util/evsel_fprintf.h"
#include "evlist.h"
#include <perf/cpumap.h>
#include "thread_map.h"
#include "target.h"
#include "perf_regs.h"
#include "record.h"
#include "debug.h"
#include "trace-event.h"
#include "stat.h"
#include "string2.h"
#include "memswap.h"
#include "util.h"
#include "../perf-sys.h"
#include "util/parse-branch-options.h"
#include <internal/xyarray.h>
#include <internal/lib.h>

#include <linux/ctype.h>

struct perf_missing_features perf_missing_features;

static clockid_t clockid;

static int perf_evsel__no_extra_init(struct evsel *evsel __maybe_unused)
{
        return 0;
}

void __weak test_attr__ready(void) { }

static void perf_evsel__no_extra_fini(struct evsel *evsel __maybe_unused)
{
}

static struct {
        size_t  size;
        int     (*init)(struct evsel *evsel);
        void    (*fini)(struct evsel *evsel);
} perf_evsel__object = {
        .size = sizeof(struct evsel),
        .init = perf_evsel__no_extra_init,
        .fini = perf_evsel__no_extra_fini,
};

int perf_evsel__object_config(size_t object_size,
                              int (*init)(struct evsel *evsel),
                              void (*fini)(struct evsel *evsel))
{

        if (object_size == 0)
                goto set_methods;

        if (perf_evsel__object.size > object_size)
                return -EINVAL;

        perf_evsel__object.size = object_size;

set_methods:
        if (init != NULL)
                perf_evsel__object.init = init;

        if (fini != NULL)
                perf_evsel__object.fini = fini;

        return 0;
}

#define FD(e, x, y) (*(int *)xyarray__entry(e->core.fd, x, y))

int __perf_evsel__sample_size(u64 sample_type)
{
        u64 mask = sample_type & PERF_SAMPLE_MASK;
        int size = 0;
        int i;

        for (i = 0; i < 64; i++) {
                if (mask & (1ULL << i))
                        size++;
        }

        size *= sizeof(u64);

        return size;
}

/**
 * __perf_evsel__calc_id_pos - calculate id_pos.
 * @sample_type: sample type
 *
 * This function returns the position of the event id (PERF_SAMPLE_ID or
 * PERF_SAMPLE_IDENTIFIER) in a sample event i.e. in the array of struct
 * perf_record_sample.
 */
static int __perf_evsel__calc_id_pos(u64 sample_type)
{
        int idx = 0;

        if (sample_type & PERF_SAMPLE_IDENTIFIER)
                return 0;

        if (!(sample_type & PERF_SAMPLE_ID))
                return -1;

        if (sample_type & PERF_SAMPLE_IP)
                idx += 1;

        if (sample_type & PERF_SAMPLE_TID)
                idx += 1;

        if (sample_type & PERF_SAMPLE_TIME)
                idx += 1;

        if (sample_type & PERF_SAMPLE_ADDR)
                idx += 1;

        return idx;
}

/**
 * __perf_evsel__calc_is_pos - calculate is_pos.
 * @sample_type: sample type
 *
 * This function returns the position (counting backwards) of the event id
 * (PERF_SAMPLE_ID or PERF_SAMPLE_IDENTIFIER) in a non-sample event i.e. if
 * sample_id_all is used there is an id sample appended to non-sample events.
 */
static int __perf_evsel__calc_is_pos(u64 sample_type)
{
        int idx = 1;

        if (sample_type & PERF_SAMPLE_IDENTIFIER)
                return 1;

        if (!(sample_type & PERF_SAMPLE_ID))
                return -1;

        if (sample_type & PERF_SAMPLE_CPU)
                idx += 1;

        if (sample_type & PERF_SAMPLE_STREAM_ID)
                idx += 1;

        return idx;
}

void perf_evsel__calc_id_pos(struct evsel *evsel)
{
        evsel->id_pos = __perf_evsel__calc_id_pos(evsel->core.attr.sample_type);
        evsel->is_pos = __perf_evsel__calc_is_pos(evsel->core.attr.sample_type);
}

void __perf_evsel__set_sample_bit(struct evsel *evsel,
                                  enum perf_event_sample_format bit)
{
        if (!(evsel->core.attr.sample_type & bit)) {
                evsel->core.attr.sample_type |= bit;
                evsel->sample_size += sizeof(u64);
                perf_evsel__calc_id_pos(evsel);
        }
}

void __perf_evsel__reset_sample_bit(struct evsel *evsel,
                                    enum perf_event_sample_format bit)
{
        if (evsel->core.attr.sample_type & bit) {
                evsel->core.attr.sample_type &= ~bit;
                evsel->sample_size -= sizeof(u64);
                perf_evsel__calc_id_pos(evsel);
        }
}

void perf_evsel__set_sample_id(struct evsel *evsel,
                               bool can_sample_identifier)
{
        if (can_sample_identifier) {
                perf_evsel__reset_sample_bit(evsel, ID);
                perf_evsel__set_sample_bit(evsel, IDENTIFIER);
        } else {
                perf_evsel__set_sample_bit(evsel, ID);
        }
        evsel->core.attr.read_format |= PERF_FORMAT_ID;
}

/**
 * perf_evsel__is_function_event - Return whether given evsel is a function
 * trace event
 *
 * @evsel - evsel selector to be tested
 *
 * Return %true if event is function trace event
 */
bool perf_evsel__is_function_event(struct evsel *evsel)
{
#define FUNCTION_EVENT "ftrace:function"

        return evsel->name &&
               !strncmp(FUNCTION_EVENT, evsel->name, sizeof(FUNCTION_EVENT));

#undef FUNCTION_EVENT
}

void evsel__init(struct evsel *evsel,
                 struct perf_event_attr *attr, int idx)
{
        perf_evsel__init(&evsel->core, attr);
        evsel->idx         = idx;
        evsel->tracking    = !idx;
        evsel->leader      = evsel;
        evsel->unit        = "";
        evsel->scale       = 1.0;
        evsel->max_events  = ULONG_MAX;
        evsel->evlist      = NULL;
        evsel->bpf_obj     = NULL;
        evsel->bpf_fd      = -1;
        INIT_LIST_HEAD(&evsel->config_terms);
        perf_evsel__object.init(evsel);
        evsel->sample_size = __perf_evsel__sample_size(attr->sample_type);
        perf_evsel__calc_id_pos(evsel);
        evsel->cmdline_group_boundary = false;
        evsel->metric_expr   = NULL;
        evsel->metric_name   = NULL;
        evsel->metric_events = NULL;
        evsel->collect_stat  = false;
        evsel->pmu_name      = NULL;
}

struct evsel *perf_evsel__new_idx(struct perf_event_attr *attr, int idx)
{
        struct evsel *evsel = zalloc(perf_evsel__object.size);

        if (!evsel)
                return NULL;
        evsel__init(evsel, attr, idx);

        if (perf_evsel__is_bpf_output(evsel)) {
                evsel->core.attr.sample_type |= (PERF_SAMPLE_RAW | PERF_SAMPLE_TIME |
                                            PERF_SAMPLE_CPU | PERF_SAMPLE_PERIOD),
                evsel->core.attr.sample_period = 1;
        }

        if (perf_evsel__is_clock(evsel)) {
                /*
                 * The evsel->unit points to static alias->unit
                 * so it's ok to use static string in here.
                 */
                static const char *unit = "msec";

                evsel->unit = unit;
                evsel->scale = 1e-6;
        }

        return evsel;
}

static bool perf_event_can_profile_kernel(void)
{
        return perf_event_paranoid_check(1);
}

struct evsel *perf_evsel__new_cycles(bool precise)
{
        struct perf_event_attr attr = {
                .type   = PERF_TYPE_HARDWARE,
                .config = PERF_COUNT_HW_CPU_CYCLES,
                .exclude_kernel = !perf_event_can_profile_kernel(),
        };
        struct evsel *evsel;

        event_attr_init(&attr);

        if (!precise)
                goto new_event;

        /*
         * Now let the usual logic to set up the perf_event_attr defaults
         * to kick in when we return and before perf_evsel__open() is called.
         */
new_event:
        evsel = evsel__new(&attr);
        if (evsel == NULL)
                goto out;

        evsel->precise_max = true;

        /* use asprintf() because free(evsel) assumes name is allocated */
        if (asprintf(&evsel->name, "cycles%s%s%.*s",
                     (attr.precise_ip || attr.exclude_kernel) ? ":" : "",
                     attr.exclude_kernel ? "u" : "",
                     attr.precise_ip ? attr.precise_ip + 1 : 0, "ppp") < 0)
                goto error_free;
out:
        return evsel;
error_free:
        evsel__delete(evsel);
        evsel = NULL;
        goto out;
}

/*
 * Returns pointer with encoded error via <linux/err.h> interface.
 */
struct evsel *perf_evsel__newtp_idx(const char *sys, const char *name, int idx)
{
        struct evsel *evsel = zalloc(perf_evsel__object.size);
        int err = -ENOMEM;

        if (evsel == NULL) {
                goto out_err;
        } else {
                struct perf_event_attr attr = {
                        .type          = PERF_TYPE_TRACEPOINT,
                        .sample_type   = (PERF_SAMPLE_RAW | PERF_SAMPLE_TIME |
                                          PERF_SAMPLE_CPU | PERF_SAMPLE_PERIOD),
                };

                if (asprintf(&evsel->name, "%s:%s", sys, name) < 0)
                        goto out_free;

                evsel->tp_format = trace_event__tp_format(sys, name);
                if (IS_ERR(evsel->tp_format)) {
                        err = PTR_ERR(evsel->tp_format);
                        goto out_free;
                }

                event_attr_init(&attr);
                attr.config = evsel->tp_format->id;
                attr.sample_period = 1;
                evsel__init(evsel, &attr, idx);
        }

        return evsel;

out_free:
        zfree(&evsel->name);
        free(evsel);
out_err:
        return ERR_PTR(err);
}

const char *perf_evsel__hw_names[PERF_COUNT_HW_MAX] = {
        "cycles",
        "instructions",
        "cache-references",
        "cache-misses",
        "branches",
        "branch-misses",
        "bus-cycles",
        "stalled-cycles-frontend",
        "stalled-cycles-backend",
        "ref-cycles",
};

static const char *__perf_evsel__hw_name(u64 config)
{
        if (config < PERF_COUNT_HW_MAX && perf_evsel__hw_names[config])
                return perf_evsel__hw_names[config];

        return "unknown-hardware";
}

static int perf_evsel__add_modifiers(struct evsel *evsel, char *bf, size_t size)
{
        int colon = 0, r = 0;
        struct perf_event_attr *attr = &evsel->core.attr;
        bool exclude_guest_default = false;

#define MOD_PRINT(context, mod) do {                                    \
                if (!attr->exclude_##context) {                         \
                        if (!colon) colon = ++r;                        \
                        r += scnprintf(bf + r, size - r, "%c", mod);    \
                } } while(0)

        if (attr->exclude_kernel || attr->exclude_user || attr->exclude_hv) {
                MOD_PRINT(kernel, 'k');
                MOD_PRINT(user, 'u');
                MOD_PRINT(hv, 'h');
                exclude_guest_default = true;
        }

        if (attr->precise_ip) {
                if (!colon)
                        colon = ++r;
                r += scnprintf(bf + r, size - r, "%.*s", attr->precise_ip, "ppp");
                exclude_guest_default = true;
        }

        if (attr->exclude_host || attr->exclude_guest == exclude_guest_default) {
                MOD_PRINT(host, 'H');
                MOD_PRINT(guest, 'G');
        }
#undef MOD_PRINT
        if (colon)
                bf[colon - 1] = ':';
        return r;
}

static int perf_evsel__hw_name(struct evsel *evsel, char *bf, size_t size)
{
        int r = scnprintf(bf, size, "%s", __perf_evsel__hw_name(evsel->core.attr.config));
        return r + perf_evsel__add_modifiers(evsel, bf + r, size - r);
}

const char *perf_evsel__sw_names[PERF_COUNT_SW_MAX] = {
        "cpu-clock",
        "task-clock",
        "page-faults",
        "context-switches",
        "cpu-migrations",
        "minor-faults",
        "major-faults",
        "alignment-faults",
        "emulation-faults",
        "dummy",
};

static const char *__perf_evsel__sw_name(u64 config)
{
        if (config < PERF_COUNT_SW_MAX && perf_evsel__sw_names[config])
                return perf_evsel__sw_names[config];
        return "unknown-software";
}

static int perf_evsel__sw_name(struct evsel *evsel, char *bf, size_t size)
{
        int r = scnprintf(bf, size, "%s", __perf_evsel__sw_name(evsel->core.attr.config));
        return r + perf_evsel__add_modifiers(evsel, bf + r, size - r);
}

static int __perf_evsel__bp_name(char *bf, size_t size, u64 addr, u64 type)
{
        int r;

        r = scnprintf(bf, size, "mem:0x%" PRIx64 ":", addr);

        if (type & HW_BREAKPOINT_R)
                r += scnprintf(bf + r, size - r, "r");

        if (type & HW_BREAKPOINT_W)
                r += scnprintf(bf + r, size - r, "w");

        if (type & HW_BREAKPOINT_X)
                r += scnprintf(bf + r, size - r, "x");

        return r;
}

static int perf_evsel__bp_name(struct evsel *evsel, char *bf, size_t size)
{
        struct perf_event_attr *attr = &evsel->core.attr;
        int r = __perf_evsel__bp_name(bf, size, attr->bp_addr, attr->bp_type);
        return r + perf_evsel__add_modifiers(evsel, bf + r, size - r);
}

const char *perf_evsel__hw_cache[PERF_COUNT_HW_CACHE_MAX]
                                [PERF_EVSEL__MAX_ALIASES] = {
 { "L1-dcache", "l1-d",         "l1d",          "L1-data",              },
 { "L1-icache", "l1-i",         "l1i",          "L1-instruction",       },
 { "LLC",       "L2",                                                   },
 { "dTLB",      "d-tlb",        "Data-TLB",                             },
 { "iTLB",      "i-tlb",        "Instruction-TLB",                      },
 { "branch",    "branches",     "bpu",          "btb",          "bpc",  },
 { "node",                                                              },
};

const char *perf_evsel__hw_cache_op[PERF_COUNT_HW_CACHE_OP_MAX]
                                   [PERF_EVSEL__MAX_ALIASES] = {
 { "load",      "loads",        "read",                                 },
 { "store",     "stores",       "write",                                },
 { "prefetch",  "prefetches",   "speculative-read", "speculative-load", },
};

const char *perf_evsel__hw_cache_result[PERF_COUNT_HW_CACHE_RESULT_MAX]
                                       [PERF_EVSEL__MAX_ALIASES] = {
 { "refs",      "Reference",    "ops",          "access",               },
 { "misses",    "miss",                                                 },
};

#define C(x)            PERF_COUNT_HW_CACHE_##x
#define CACHE_READ      (1 << C(OP_READ))
#define CACHE_WRITE     (1 << C(OP_WRITE))
#define CACHE_PREFETCH  (1 << C(OP_PREFETCH))
#define COP(x)          (1 << x)

/*
 * cache operartion stat
 * L1I : Read and prefetch only
 * ITLB and BPU : Read-only
 */
static unsigned long perf_evsel__hw_cache_stat[C(MAX)] = {
 [C(L1D)]       = (CACHE_READ | CACHE_WRITE | CACHE_PREFETCH),
 [C(L1I)]       = (CACHE_READ | CACHE_PREFETCH),
 [C(LL)]        = (CACHE_READ | CACHE_WRITE | CACHE_PREFETCH),
 [C(DTLB)]      = (CACHE_READ | CACHE_WRITE | CACHE_PREFETCH),
 [C(ITLB)]      = (CACHE_READ),
 [C(BPU)]       = (CACHE_READ),
 [C(NODE)]      = (CACHE_READ | CACHE_WRITE | CACHE_PREFETCH),
};

bool perf_evsel__is_cache_op_valid(u8 type, u8 op)
{
        if (perf_evsel__hw_cache_stat[type] & COP(op))
                return true;    /* valid */
        else
                return false;   /* invalid */
}

int __perf_evsel__hw_cache_type_op_res_name(u8 type, u8 op, u8 result,
                                            char *bf, size_t size)
{
        if (result) {
                return scnprintf(bf, size, "%s-%s-%s", perf_evsel__hw_cache[type][0],
                                 perf_evsel__hw_cache_op[op][0],
                                 perf_evsel__hw_cache_result[result][0]);
        }

        return scnprintf(bf, size, "%s-%s", perf_evsel__hw_cache[type][0],
                         perf_evsel__hw_cache_op[op][1]);
}

static int __perf_evsel__hw_cache_name(u64 config, char *bf, size_t size)
{
        u8 op, result, type = (config >>  0) & 0xff;
        const char *err = "unknown-ext-hardware-cache-type";

        if (type >= PERF_COUNT_HW_CACHE_MAX)
                goto out_err;

        op = (config >>  8) & 0xff;
        err = "unknown-ext-hardware-cache-op";
        if (op >= PERF_COUNT_HW_CACHE_OP_MAX)
                goto out_err;

        result = (config >> 16) & 0xff;
        err = "unknown-ext-hardware-cache-result";
        if (result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
                goto out_err;

        err = "invalid-cache";
        if (!perf_evsel__is_cache_op_valid(type, op))
                goto out_err;

        return __perf_evsel__hw_cache_type_op_res_name(type, op, result, bf, size);
out_err:
        return scnprintf(bf, size, "%s", err);
}

static int perf_evsel__hw_cache_name(struct evsel *evsel, char *bf, size_t size)
{
        int ret = __perf_evsel__hw_cache_name(evsel->core.attr.config, bf, size);
        return ret + perf_evsel__add_modifiers(evsel, bf + ret, size - ret);
}

static int perf_evsel__raw_name(struct evsel *evsel, char *bf, size_t size)
{
        int ret = scnprintf(bf, size, "raw 0x%" PRIx64, evsel->core.attr.config);
        return ret + perf_evsel__add_modifiers(evsel, bf + ret, size - ret);
}

static int perf_evsel__tool_name(char *bf, size_t size)
{
        int ret = scnprintf(bf, size, "duration_time");
        return ret;
}

const char *perf_evsel__name(struct evsel *evsel)
{
        char bf[128];

        if (!evsel)
                goto out_unknown;

        if (evsel->name)
                return evsel->name;

        switch (evsel->core.attr.type) {
        case PERF_TYPE_RAW:
                perf_evsel__raw_name(evsel, bf, sizeof(bf));
                break;

        case PERF_TYPE_HARDWARE:
                perf_evsel__hw_name(evsel, bf, sizeof(bf));
                break;

        case PERF_TYPE_HW_CACHE:
                perf_evsel__hw_cache_name(evsel, bf, sizeof(bf));
                break;

        case PERF_TYPE_SOFTWARE:
                if (evsel->tool_event)
                        perf_evsel__tool_name(bf, sizeof(bf));
                else
                        perf_evsel__sw_name(evsel, bf, sizeof(bf));
                break;

        case PERF_TYPE_TRACEPOINT:
                scnprintf(bf, sizeof(bf), "%s", "unknown tracepoint");
                break;

        case PERF_TYPE_BREAKPOINT:
                perf_evsel__bp_name(evsel, bf, sizeof(bf));
                break;

        default:
                scnprintf(bf, sizeof(bf), "unknown attr type: %d",
                          evsel->core.attr.type);
                break;
        }

        evsel->name = strdup(bf);

        if (evsel->name)
                return evsel->name;
out_unknown:
        return "unknown";
}

const char *perf_evsel__group_name(struct evsel *evsel)
{
        return evsel->group_name ?: "anon group";
}

/*
 * Returns the group details for the specified leader,
 * with following rules.
 *
 *  For record -e '{cycles,instructions}'
 *    'anon group { cycles:u, instructions:u }'
 *
 *  For record -e 'cycles,instructions' and report --group
 *    'cycles:u, instructions:u'
 */
int perf_evsel__group_desc(struct evsel *evsel, char *buf, size_t size)
{
        int ret = 0;
        struct evsel *pos;
        const char *group_name = perf_evsel__group_name(evsel);

        if (!evsel->forced_leader)
                ret = scnprintf(buf, size, "%s { ", group_name);

        ret += scnprintf(buf + ret, size - ret, "%s",
                         perf_evsel__name(evsel));

        for_each_group_member(pos, evsel)
                ret += scnprintf(buf + ret, size - ret, ", %s",
                                 perf_evsel__name(pos));

        if (!evsel->forced_leader)
                ret += scnprintf(buf + ret, size - ret, " }");

        return ret;
}

static void __perf_evsel__config_callchain(struct evsel *evsel,
                                           struct record_opts *opts,
                                           struct callchain_param *param)
{
        bool function = perf_evsel__is_function_event(evsel);
        struct perf_event_attr *attr = &evsel->core.attr;

        perf_evsel__set_sample_bit(evsel, CALLCHAIN);

        attr->sample_max_stack = param->max_stack;

        if (opts->kernel_callchains)
                attr->exclude_callchain_user = 1;
        if (opts->user_callchains)
                attr->exclude_callchain_kernel = 1;
        if (param->record_mode == CALLCHAIN_LBR) {
                if (!opts->branch_stack) {
                        if (attr->exclude_user) {
                                pr_warning("LBR callstack option is only available "
                                           "to get user callchain information. "
                                           "Falling back to framepointers.\n");
                        } else {
                                perf_evsel__set_sample_bit(evsel, BRANCH_STACK);
                                attr->branch_sample_type = PERF_SAMPLE_BRANCH_USER |
                                                        PERF_SAMPLE_BRANCH_CALL_STACK |
                                                        PERF_SAMPLE_BRANCH_NO_CYCLES |
                                                        PERF_SAMPLE_BRANCH_NO_FLAGS;
                        }
                } else
                         pr_warning("Cannot use LBR callstack with branch stack. "
                                    "Falling back to framepointers.\n");
        }

        if (param->record_mode == CALLCHAIN_DWARF) {
                if (!function) {
                        perf_evsel__set_sample_bit(evsel, REGS_USER);
                        perf_evsel__set_sample_bit(evsel, STACK_USER);
                        if (opts->sample_user_regs && DWARF_MINIMAL_REGS != PERF_REGS_MASK) {
                                attr->sample_regs_user |= DWARF_MINIMAL_REGS;
                                pr_warning("WARNING: The use of --call-graph=dwarf may require all the user registers, "
                                           "specifying a subset with --user-regs may render DWARF unwinding unreliable, "
                                           "so the minimal registers set (IP, SP) is explicitly forced.\n");
                        } else {
                                attr->sample_regs_user |= PERF_REGS_MASK;
                        }
                        attr->sample_stack_user = param->dump_size;
                        attr->exclude_callchain_user = 1;
                } else {
                        pr_info("Cannot use DWARF unwind for function trace event,"
                                " falling back to framepointers.\n");
                }
        }

        if (function) {
                pr_info("Disabling user space callchains for function trace event.\n");
                attr->exclude_callchain_user = 1;
        }
}

void perf_evsel__config_callchain(struct evsel *evsel,
                                  struct record_opts *opts,
                                  struct callchain_param *param)
{
        if (param->enabled)
                return __perf_evsel__config_callchain(evsel, opts, param);
}

static void
perf_evsel__reset_callgraph(struct evsel *evsel,
                            struct callchain_param *param)
{
        struct perf_event_attr *attr = &evsel->core.attr;

        perf_evsel__reset_sample_bit(evsel, CALLCHAIN);
        if (param->record_mode == CALLCHAIN_LBR) {
                perf_evsel__reset_sample_bit(evsel, BRANCH_STACK);
                attr->branch_sample_type &= ~(PERF_SAMPLE_BRANCH_USER |
                                              PERF_SAMPLE_BRANCH_CALL_STACK);
        }
        if (param->record_mode == CALLCHAIN_DWARF) {
                perf_evsel__reset_sample_bit(evsel, REGS_USER);
                perf_evsel__reset_sample_bit(evsel, STACK_USER);
        }
}

static void apply_config_terms(struct evsel *evsel,
                               struct record_opts *opts, bool track)
{
        struct perf_evsel_config_term *term;
        struct list_head *config_terms = &evsel->config_terms;
        struct perf_event_attr *attr = &evsel->core.attr;
        /* callgraph default */
        struct callchain_param param = {
                .record_mode = callchain_param.record_mode,
        };
        u32 dump_size = 0;
        int max_stack = 0;
        const char *callgraph_buf = NULL;

        list_for_each_entry(term, config_terms, list) {
                switch (term->type) {
                case PERF_EVSEL__CONFIG_TERM_PERIOD:
                        if (!(term->weak && opts->user_interval != ULLONG_MAX)) {
                                attr->sample_period = term->val.period;
                                attr->freq = 0;
                                perf_evsel__reset_sample_bit(evsel, PERIOD);
                        }
                        break;
                case PERF_EVSEL__CONFIG_TERM_FREQ:
                        if (!(term->weak && opts->user_freq != UINT_MAX)) {
                                attr->sample_freq = term->val.freq;
                                attr->freq = 1;
                                perf_evsel__set_sample_bit(evsel, PERIOD);
                        }
                        break;
                case PERF_EVSEL__CONFIG_TERM_TIME:
                        if (term->val.time)
                                perf_evsel__set_sample_bit(evsel, TIME);
                        else
                                perf_evsel__reset_sample_bit(evsel, TIME);
                        break;
                case PERF_EVSEL__CONFIG_TERM_CALLGRAPH:
                        callgraph_buf = term->val.callgraph;
                        break;
                case PERF_EVSEL__CONFIG_TERM_BRANCH:
                        if (term->val.branch && strcmp(term->val.branch, "no")) {
                                perf_evsel__set_sample_bit(evsel, BRANCH_STACK);
                                parse_branch_str(term->val.branch,
                                                 &attr->branch_sample_type);
                        } else
                                perf_evsel__reset_sample_bit(evsel, BRANCH_STACK);
                        break;
                case PERF_EVSEL__CONFIG_TERM_STACK_USER:
                        dump_size = term->val.stack_user;
                        break;
                case PERF_EVSEL__CONFIG_TERM_MAX_STACK:
                        max_stack = term->val.max_stack;
                        break;
                case PERF_EVSEL__CONFIG_TERM_MAX_EVENTS:
                        evsel->max_events = term->val.max_events;
                        break;
                case PERF_EVSEL__CONFIG_TERM_INHERIT:
                        /*
                         * attr->inherit should has already been set by
                         * perf_evsel__config. If user explicitly set
                         * inherit using config terms, override global
                         * opt->no_inherit setting.
                         */
                        attr->inherit = term->val.inherit ? 1 : 0;
                        break;
                case PERF_EVSEL__CONFIG_TERM_OVERWRITE:
                        attr->write_backward = term->val.overwrite ? 1 : 0;
                        break;
                case PERF_EVSEL__CONFIG_TERM_DRV_CFG:
                        break;
                case PERF_EVSEL__CONFIG_TERM_PERCORE:
                        break;
                case PERF_EVSEL__CONFIG_TERM_AUX_OUTPUT:
                        attr->aux_output = term->val.aux_output ? 1 : 0;
                        break;
                default:
                        break;
                }
        }

        /* User explicitly set per-event callgraph, clear the old setting and reset. */
        if ((callgraph_buf != NULL) || (dump_size > 0) || max_stack) {
                bool sample_address = false;

                if (max_stack) {
                        param.max_stack = max_stack;
                        if (callgraph_buf == NULL)
                                callgraph_buf = "fp";
                }

                /* parse callgraph parameters */
                if (callgraph_buf != NULL) {
                        if (!strcmp(callgraph_buf, "no")) {
                                param.enabled = false;
                                param.record_mode = CALLCHAIN_NONE;
                        } else {
                                param.enabled = true;
                                if (parse_callchain_record(callgraph_buf, &param)) {
                                        pr_err("per-event callgraph setting for %s failed. "
                                               "Apply callgraph global setting for it\n",
                                               evsel->name);
                                        return;
                                }
                                if (param.record_mode == CALLCHAIN_DWARF)
                                        sample_address = true;
                        }
                }
                if (dump_size > 0) {
                        dump_size = round_up(dump_size, sizeof(u64));
                        param.dump_size = dump_size;
                }

                /* If global callgraph set, clear it */
                if (callchain_param.enabled)
                        perf_evsel__reset_callgraph(evsel, &callchain_param);

                /* set perf-event callgraph */
                if (param.enabled) {
                        if (sample_address) {
                                perf_evsel__set_sample_bit(evsel, ADDR);
                                perf_evsel__set_sample_bit(evsel, DATA_SRC);
                                evsel->core.attr.mmap_data = track;
                        }
                        perf_evsel__config_callchain(evsel, opts, &param);
                }
        }
}

static bool is_dummy_event(struct evsel *evsel)
{
        return (evsel->core.attr.type == PERF_TYPE_SOFTWARE) &&
               (evsel->core.attr.config == PERF_COUNT_SW_DUMMY);
}

/*
 * The enable_on_exec/disabled value strategy:
 *
 *  1) For any type of traced program:
 *    - all independent events and group leaders are disabled
 *    - all group members are enabled
 *
 *     Group members are ruled by group leaders. They need to
 *     be enabled, because the group scheduling relies on that.
 *
 *  2) For traced programs executed by perf:
 *     - all independent events and group leaders have
 *       enable_on_exec set
 *     - we don't specifically enable or disable any event during
 *       the record command
 *
 *     Independent events and group leaders are initially disabled
 *     and get enabled by exec. Group members are ruled by group
 *     leaders as stated in 1).
 *
 *  3) For traced programs attached by perf (pid/tid):
 *     - we specifically enable or disable all events during
 *       the record command
 *
 *     When attaching events to already running traced we
 *     enable/disable events specifically, as there's no
 *     initial traced exec call.
 */
void perf_evsel__config(struct evsel *evsel, struct record_opts *opts,
                        struct callchain_param *callchain)
{
        struct evsel *leader = evsel->leader;
        struct perf_event_attr *attr = &evsel->core.attr;
        int track = evsel->tracking;
        bool per_cpu = opts->target.default_per_cpu && !opts->target.per_thread;

        attr->sample_id_all = perf_missing_features.sample_id_all ? 0 : 1;
        attr->inherit       = !opts->no_inherit;
        attr->write_backward = opts->overwrite ? 1 : 0;

        perf_evsel__set_sample_bit(evsel, IP);
        perf_evsel__set_sample_bit(evsel, TID);

        if (evsel->sample_read) {
                perf_evsel__set_sample_bit(evsel, READ);

                /*
                 * We need ID even in case of single event, because
                 * PERF_SAMPLE_READ process ID specific data.
                 */
                perf_evsel__set_sample_id(evsel, false);

                /*
                 * Apply group format only if we belong to group
                 * with more than one members.
                 */
                if (leader->core.nr_members > 1) {
                        attr->read_format |= PERF_FORMAT_GROUP;
                        attr->inherit = 0;
                }
        }

        /*
         * We default some events to have a default interval. But keep
         * it a weak assumption overridable by the user.
         */
        if (!attr->sample_period || (opts->user_freq != UINT_MAX ||
                                     opts->user_interval != ULLONG_MAX)) {
                if (opts->freq) {
                        perf_evsel__set_sample_bit(evsel, PERIOD);
                        attr->freq              = 1;
                        attr->sample_freq       = opts->freq;
                } else {
                        attr->sample_period = opts->default_interval;
                }
        }

        /*
         * Disable sampling for all group members other
         * than leader in case leader 'leads' the sampling.
         */
        if ((leader != evsel) && leader->sample_read) {
                attr->freq           = 0;
                attr->sample_freq    = 0;
                attr->sample_period  = 0;
                attr->write_backward = 0;

                /*
                 * We don't get sample for slave events, we make them
                 * when delivering group leader sample. Set the slave
                 * event to follow the master sample_type to ease up
                 * report.
                 */

                attr->sample_type = leader->core.attr.sample_type;
        }

        if (opts->no_samples)
                attr->sample_freq = 0;

        if (opts->inherit_stat) {
                evsel->core.attr.read_format |=
                        PERF_FORMAT_TOTAL_TIME_ENABLED |
                        PERF_FORMAT_TOTAL_TIME_RUNNING |
                        PERF_FORMAT_ID;
                attr->inherit_stat = 1;
        }

        if (opts->sample_address) {
                perf_evsel__set_sample_bit(evsel, ADDR);
                attr->mmap_data = track;
        }

        /*
         * We don't allow user space callchains for  function trace
         * event, due to issues with page faults while tracing page
         * fault handler and its overall trickiness nature.
         */
        if (perf_evsel__is_function_event(evsel))
                evsel->core.attr.exclude_callchain_user = 1;

        if (callchain && callchain->enabled && !evsel->no_aux_samples)
                perf_evsel__config_callchain(evsel, opts, callchain);

        if (opts->sample_intr_regs) {
                attr->sample_regs_intr = opts->sample_intr_regs;
                perf_evsel__set_sample_bit(evsel, REGS_INTR);
        }

        if (opts->sample_user_regs) {
                attr->sample_regs_user |= opts->sample_user_regs;
                perf_evsel__set_sample_bit(evsel, REGS_USER);
        }

        if (target__has_cpu(&opts->target) || opts->sample_cpu)
                perf_evsel__set_sample_bit(evsel, CPU);

        /*
         * When the user explicitly disabled time don't force it here.
         */
        if (opts->sample_time &&
            (!perf_missing_features.sample_id_all &&
            (!opts->no_inherit || target__has_cpu(&opts->target) || per_cpu ||
             opts->sample_time_set)))
                perf_evsel__set_sample_bit(evsel, TIME);

        if (opts->raw_samples && !evsel->no_aux_samples) {
                perf_evsel__set_sample_bit(evsel, TIME);
                perf_evsel__set_sample_bit(evsel, RAW);
                perf_evsel__set_sample_bit(evsel, CPU);
        }

        if (opts->sample_address)
                perf_evsel__set_sample_bit(evsel, DATA_SRC);

        if (opts->sample_phys_addr)
                perf_evsel__set_sample_bit(evsel, PHYS_ADDR);

        if (opts->no_buffering) {
                attr->watermark = 0;
                attr->wakeup_events = 1;
        }
        if (opts->branch_stack && !evsel->no_aux_samples) {
                perf_evsel__set_sample_bit(evsel, BRANCH_STACK);
                attr->branch_sample_type = opts->branch_stack;
        }

        if (opts->sample_weight)
                perf_evsel__set_sample_bit(evsel, WEIGHT);

        attr->task  = track;
        attr->mmap  = track;
        attr->mmap2 = track && !perf_missing_features.mmap2;
        attr->comm  = track;
        attr->ksymbol = track && !perf_missing_features.ksymbol;
        attr->bpf_event = track && !opts->no_bpf_event && !perf_missing_features.bpf;

        if (opts->record_namespaces)
                attr->namespaces  = track;

        if (opts->record_switch_events)
                attr->context_switch = track;

        if (opts->sample_transaction)
                perf_evsel__set_sample_bit(evsel, TRANSACTION);

        if (opts->running_time) {
                evsel->core.attr.read_format |=
                        PERF_FORMAT_TOTAL_TIME_ENABLED |
                        PERF_FORMAT_TOTAL_TIME_RUNNING;
        }

        /*
         * XXX see the function comment above
         *
         * Disabling only independent events or group leaders,
         * keeping group members enabled.
         */
        if (perf_evsel__is_group_leader(evsel))
                attr->disabled = 1;

        /*
         * Setting enable_on_exec for independent events and
         * group leaders for traced executed by perf.
         */
        if (target__none(&opts->target) && perf_evsel__is_group_leader(evsel) &&
                !opts->initial_delay)
                attr->enable_on_exec = 1;

        if (evsel->immediate) {
                attr->disabled = 0;
                attr->enable_on_exec = 0;
        }

        clockid = opts->clockid;
        if (opts->use_clockid) {
                attr->use_clockid = 1;
                attr->clockid = opts->clockid;
        }

        if (evsel->precise_max)
                attr->precise_ip = 3;

        if (opts->all_user) {
                attr->exclude_kernel = 1;
                attr->exclude_user   = 0;
        }

        if (opts->all_kernel) {
                attr->exclude_kernel = 0;
                attr->exclude_user   = 1;
        }

        if (evsel->core.own_cpus || evsel->unit)
                evsel->core.attr.read_format |= PERF_FORMAT_ID;

        /*
         * Apply event specific term settings,
         * it overloads any global configuration.
         */
        apply_config_terms(evsel, opts, track);

        evsel->ignore_missing_thread = opts->ignore_missing_thread;

        /* The --period option takes the precedence. */
        if (opts->period_set) {
                if (opts->period)
                        perf_evsel__set_sample_bit(evsel, PERIOD);
                else
                        perf_evsel__reset_sample_bit(evsel, PERIOD);
        }

        /*
         * For initial_delay, a dummy event is added implicitly.
         * The software event will trigger -EOPNOTSUPP error out,
         * if BRANCH_STACK bit is set.
         */
        if (opts->initial_delay && is_dummy_event(evsel))
                perf_evsel__reset_sample_bit(evsel, BRANCH_STACK);
}

int perf_evsel__set_filter(struct evsel *evsel, const char *filter)
{
        char *new_filter = strdup(filter);

        if (new_filter != NULL) {
                free(evsel->filter);
                evsel->filter = new_filter;
                return 0;
        }

        return -1;
}

static int perf_evsel__append_filter(struct evsel *evsel,
                                     const char *fmt, const char *filter)
{
        char *new_filter;

        if (evsel->filter == NULL)
                return perf_evsel__set_filter(evsel, filter);

        if (asprintf(&new_filter, fmt, evsel->filter, filter) > 0) {
                free(evsel->filter);
                evsel->filter = new_filter;
                return 0;
        }

        return -1;
}

int perf_evsel__append_tp_filter(struct evsel *evsel, const char *filter)
{
        return perf_evsel__append_filter(evsel, "(%s) && (%s)", filter);
}

int perf_evsel__append_addr_filter(struct evsel *evsel, const char *filter)
{
        return perf_evsel__append_filter(evsel, "%s,%s", filter);
}

int evsel__enable(struct evsel *evsel)
{
        int err = perf_evsel__enable(&evsel->core);

        if (!err)
                evsel->disabled = false;

        return err;
}

int evsel__disable(struct evsel *evsel)
{
        int err = perf_evsel__disable(&evsel->core);
        /*
         * We mark it disabled here so that tools that disable a event can
         * ignore events after they disable it. I.e. the ring buffer may have
         * already a few more events queued up before the kernel got the stop
         * request.
         */
        if (!err)
                evsel->disabled = true;

        return err;
}

static void perf_evsel__free_config_terms(struct evsel *evsel)
{
        struct perf_evsel_config_term *term, *h;

        list_for_each_entry_safe(term, h, &evsel->config_terms, list) {
                list_del_init(&term->list);
                free(term);
        }
}

void perf_evsel__exit(struct evsel *evsel)
{
        assert(list_empty(&evsel->core.node));
        assert(evsel->evlist == NULL);
        perf_evsel__free_counts(evsel);
        perf_evsel__free_fd(&evsel->core);
        perf_evsel__free_id(&evsel->core);
        perf_evsel__free_config_terms(evsel);
        cgroup__put(evsel->cgrp);
        perf_cpu_map__put(evsel->core.cpus);
        perf_cpu_map__put(evsel->core.own_cpus);
        perf_thread_map__put(evsel->core.threads);
        zfree(&evsel->group_name);
        zfree(&evsel->name);
        perf_evsel__object.fini(evsel);
}

void evsel__delete(struct evsel *evsel)
{
        perf_evsel__exit(evsel);
        free(evsel);
}

void perf_evsel__compute_deltas(struct evsel *evsel, int cpu, int thread,
                                struct perf_counts_values *count)
{
        struct perf_counts_values tmp;

        if (!evsel->prev_raw_counts)
                return;

        if (cpu == -1) {
                tmp = evsel->prev_raw_counts->aggr;
                evsel->prev_raw_counts->aggr = *count;
        } else {
                tmp = *perf_counts(evsel->prev_raw_counts, cpu, thread);
                *perf_counts(evsel->prev_raw_counts, cpu, thread) = *count;
        }

        count->val = count->val - tmp.val;
        count->ena = count->ena - tmp.ena;
        count->run = count->run - tmp.run;
}

void perf_counts_values__scale(struct perf_counts_values *count,
                               bool scale, s8 *pscaled)
{
        s8 scaled = 0;

        if (scale) {
                if (count->run == 0) {
                        scaled = -1;
                        count->val = 0;
                } else if (count->run < count->ena) {
                        scaled = 1;
                        count->val = (u64)((double) count->val * count->ena / count->run);
                }
        }

        if (pscaled)
                *pscaled = scaled;
}

static int
perf_evsel__read_one(struct evsel *evsel, int cpu, int thread)
{
        struct perf_counts_values *count = perf_counts(evsel->counts, cpu, thread);

        return perf_evsel__read(&evsel->core, cpu, thread, count);
}

static void
perf_evsel__set_count(struct evsel *counter, int cpu, int thread,
                      u64 val, u64 ena, u64 run)
{
        struct perf_counts_values *count;

        count = perf_counts(counter->counts, cpu, thread);

        count->val    = val;
        count->ena    = ena;
        count->run    = run;

        perf_counts__set_loaded(counter->counts, cpu, thread, true);
}

static int
perf_evsel__process_group_data(struct evsel *leader,
                               int cpu, int thread, u64 *data)
{
        u64 read_format = leader->core.attr.read_format;
        struct sample_read_value *v;
        u64 nr, ena = 0, run = 0, i;

        nr = *data++;

        if (nr != (u64) leader->core.nr_members)
                return -EINVAL;

        if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
                ena = *data++;

        if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
                run = *data++;

        v = (struct sample_read_value *) data;

        perf_evsel__set_count(leader, cpu, thread,
                              v[0].value, ena, run);

        for (i = 1; i < nr; i++) {
                struct evsel *counter;

                counter = perf_evlist__id2evsel(leader->evlist, v[i].id);
                if (!counter)
                        return -EINVAL;

                perf_evsel__set_count(counter, cpu, thread,
                                      v[i].value, ena, run);
        }

        return 0;
}

static int
perf_evsel__read_group(struct evsel *leader, int cpu, int thread)
{
        struct perf_stat_evsel *ps = leader->stats;
        u64 read_format = leader->core.attr.read_format;
        int size = perf_evsel__read_size(&leader->core);
        u64 *data = ps->group_data;

        if (!(read_format & PERF_FORMAT_ID))
                return -EINVAL;

        if (!perf_evsel__is_group_leader(leader))
                return -EINVAL;

        if (!data) {
                data = zalloc(size);
                if (!data)
                        return -ENOMEM;

                ps->group_data = data;
        }

        if (FD(leader, cpu, thread) < 0)
                return -EINVAL;

        if (readn(FD(leader, cpu, thread), data, size) <= 0)
                return -errno;

        return perf_evsel__process_group_data(leader, cpu, thread, data);
}

int perf_evsel__read_counter(struct evsel *evsel, int cpu, int thread)
{
        u64 read_format = evsel->core.attr.read_format;

        if (read_format & PERF_FORMAT_GROUP)
                return perf_evsel__read_group(evsel, cpu, thread);
        else
                return perf_evsel__read_one(evsel, cpu, thread);
}

int __perf_evsel__read_on_cpu(struct evsel *evsel,
                              int cpu, int thread, bool scale)
{
        struct perf_counts_values count;
        size_t nv = scale ? 3 : 1;

        if (FD(evsel, cpu, thread) < 0)
                return -EINVAL;

        if (evsel->counts == NULL && perf_evsel__alloc_counts(evsel, cpu + 1, thread + 1) < 0)
                return -ENOMEM;

        if (readn(FD(evsel, cpu, thread), &count, nv * sizeof(u64)) <= 0)
                return -errno;

        perf_evsel__compute_deltas(evsel, cpu, thread, &count);
        perf_counts_values__scale(&count, scale, NULL);
        *perf_counts(evsel->counts, cpu, thread) = count;
        return 0;
}

static int get_group_fd(struct evsel *evsel, int cpu, int thread)
{
        struct evsel *leader = evsel->leader;
        int fd;

        if (perf_evsel__is_group_leader(evsel))
                return -1;

        /*
         * Leader must be already processed/open,
         * if not it's a bug.
         */
        BUG_ON(!leader->core.fd);

        fd = FD(leader, cpu, thread);
        BUG_ON(fd == -1);

        return fd;
}

static void perf_evsel__remove_fd(struct evsel *pos,
                                  int nr_cpus, int nr_threads,
                                  int thread_idx)
{
        for (int cpu = 0; cpu < nr_cpus; cpu++)
                for (int thread = thread_idx; thread < nr_threads - 1; thread++)
                        FD(pos, cpu, thread) = FD(pos, cpu, thread + 1);
}

static int update_fds(struct evsel *evsel,
                      int nr_cpus, int cpu_idx,
                      int nr_threads, int thread_idx)
{
        struct evsel *pos;

        if (cpu_idx >= nr_cpus || thread_idx >= nr_threads)
                return -EINVAL;

        evlist__for_each_entry(evsel->evlist, pos) {
                nr_cpus = pos != evsel ? nr_cpus : cpu_idx;

                perf_evsel__remove_fd(pos, nr_cpus, nr_threads, thread_idx);

                /*
                 * Since fds for next evsel has not been created,
                 * there is no need to iterate whole event list.
                 */
                if (pos == evsel)
                        break;
        }
        return 0;
}

static bool ignore_missing_thread(struct evsel *evsel,
                                  int nr_cpus, int cpu,
                                  struct perf_thread_map *threads,
                                  int thread, int err)
{
        pid_t ignore_pid = perf_thread_map__pid(threads, thread);

        if (!evsel->ignore_missing_thread)
                return false;

        /* The system wide setup does not work with threads. */
        if (evsel->core.system_wide)
                return false;

        /* The -ESRCH is perf event syscall errno for pid's not found. */
        if (err != -ESRCH)
                return false;

        /* If there's only one thread, let it fail. */
        if (threads->nr == 1)
                return false;

        /*
         * We should remove fd for missing_thread first
         * because thread_map__remove() will decrease threads->nr.
         */
        if (update_fds(evsel, nr_cpus, cpu, threads->nr, thread))
                return false;

        if (thread_map__remove(threads, thread))
                return false;

        pr_warning("WARNING: Ignored open failure for pid %d\n",
                   ignore_pid);
        return true;
}

static int __open_attr__fprintf(FILE *fp, const char *name, const char *val,
                                void *priv __maybe_unused)
{
        return fprintf(fp, "  %-32s %s\n", name, val);
}

static void display_attr(struct perf_event_attr *attr)
{
        if (verbose >= 2) {
                fprintf(stderr, "%.60s\n", graph_dotted_line);
                fprintf(stderr, "perf_event_attr:\n");
                perf_event_attr__fprintf(stderr, attr, __open_attr__fprintf, NULL);
                fprintf(stderr, "%.60s\n", graph_dotted_line);
        }
}

static int perf_event_open(struct evsel *evsel,
                           pid_t pid, int cpu, int group_fd,
                           unsigned long flags)
{
        int precise_ip = evsel->core.attr.precise_ip;
        int fd;

        while (1) {
                pr_debug2("sys_perf_event_open: pid %d  cpu %d  group_fd %d  flags %#lx",
                          pid, cpu, group_fd, flags);

                fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, group_fd, flags);
                if (fd >= 0)
                        break;

                /* Do not try less precise if not requested. */
                if (!evsel->precise_max)
                        break;

                /*
                 * We tried all the precise_ip values, and it's
                 * still failing, so leave it to standard fallback.
                 */
                if (!evsel->core.attr.precise_ip) {
                        evsel->core.attr.precise_ip = precise_ip;
                        break;
                }

                pr_debug2("\nsys_perf_event_open failed, error %d\n", -ENOTSUP);
                evsel->core.attr.precise_ip--;
                pr_debug2("decreasing precise_ip by one (%d)\n", evsel->core.attr.precise_ip);
                display_attr(&evsel->core.attr);
        }

        return fd;
}

int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus,
                struct perf_thread_map *threads)
{
        int cpu, thread, nthreads;
        unsigned long flags = PERF_FLAG_FD_CLOEXEC;
        int pid = -1, err;
        enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE;

        if ((perf_missing_features.write_backward && evsel->core.attr.write_backward) ||
            (perf_missing_features.aux_output     && evsel->core.attr.aux_output))
                return -EINVAL;

        if (cpus == NULL) {
                static struct perf_cpu_map *empty_cpu_map;

                if (empty_cpu_map == NULL) {
                        empty_cpu_map = perf_cpu_map__dummy_new();
                        if (empty_cpu_map == NULL)
                                return -ENOMEM;
                }

                cpus = empty_cpu_map;
        }

        if (threads == NULL) {
                static struct perf_thread_map *empty_thread_map;

                if (empty_thread_map == NULL) {
                        empty_thread_map = thread_map__new_by_tid(-1);
                        if (empty_thread_map == NULL)
                                return -ENOMEM;
                }

                threads = empty_thread_map;
        }

        if (evsel->core.system_wide)
                nthreads = 1;
        else
                nthreads = threads->nr;

        if (evsel->core.fd == NULL &&
            perf_evsel__alloc_fd(&evsel->core, cpus->nr, nthreads) < 0)
                return -ENOMEM;

        if (evsel->cgrp) {
                flags |= PERF_FLAG_PID_CGROUP;
                pid = evsel->cgrp->fd;
        }

fallback_missing_features:
        if (perf_missing_features.clockid_wrong)
                evsel->core.attr.clockid = CLOCK_MONOTONIC; /* should always work */
        if (perf_missing_features.clockid) {
                evsel->core.attr.use_clockid = 0;
                evsel->core.attr.clockid = 0;
        }
        if (perf_missing_features.cloexec)
                flags &= ~(unsigned long)PERF_FLAG_FD_CLOEXEC;
        if (perf_missing_features.mmap2)
                evsel->core.attr.mmap2 = 0;
        if (perf_missing_features.exclude_guest)
                evsel->core.attr.exclude_guest = evsel->core.attr.exclude_host = 0;
        if (perf_missing_features.lbr_flags)
                evsel->core.attr.branch_sample_type &= ~(PERF_SAMPLE_BRANCH_NO_FLAGS |
                                     PERF_SAMPLE_BRANCH_NO_CYCLES);
        if (perf_missing_features.group_read && evsel->core.attr.inherit)
                evsel->core.attr.read_format &= ~(PERF_FORMAT_GROUP|PERF_FORMAT_ID);
        if (perf_missing_features.ksymbol)
                evsel->core.attr.ksymbol = 0;
        if (perf_missing_features.bpf)
                evsel->core.attr.bpf_event = 0;
retry_sample_id:
        if (perf_missing_features.sample_id_all)
                evsel->core.attr.sample_id_all = 0;

        display_attr(&evsel->core.attr);

        for (cpu = 0; cpu < cpus->nr; cpu++) {

                for (thread = 0; thread < nthreads; thread++) {
                        int fd, group_fd;

                        if (!evsel->cgrp && !evsel->core.system_wide)
                                pid = perf_thread_map__pid(threads, thread);

                        group_fd = get_group_fd(evsel, cpu, thread);
retry_open:
                        test_attr__ready();

                        fd = perf_event_open(evsel, pid, cpus->map[cpu],
                                             group_fd, flags);

                        FD(evsel, cpu, thread) = fd;

                        if (fd < 0) {
                                err = -errno;

                                if (ignore_missing_thread(evsel, cpus->nr, cpu, threads, thread, err)) {
                                        /*
                                         * We just removed 1 thread, so take a step
                                         * back on thread index and lower the upper
                                         * nthreads limit.
                                         */
                                        nthreads--;
                                        thread--;

                                        /* ... and pretend like nothing have happened. */
                                        err = 0;
                                        continue;
                                }

                                pr_debug2("\nsys_perf_event_open failed, error %d\n",
                                          err);
                                goto try_fallback;
                        }

                        pr_debug2(" = %d\n", fd);

                        if (evsel->bpf_fd >= 0) {
                                int evt_fd = fd;
                                int bpf_fd = evsel->bpf_fd;

                                err = ioctl(evt_fd,
                                            PERF_EVENT_IOC_SET_BPF,
                                            bpf_fd);
                                if (err && errno != EEXIST) {
                                        pr_err("failed to attach bpf fd %d: %s\n",
                                               bpf_fd, strerror(errno));
                                        err = -EINVAL;
                                        goto out_close;
                                }
                        }

                        set_rlimit = NO_CHANGE;

                        /*
                         * If we succeeded but had to kill clockid, fail and
                         * have perf_evsel__open_strerror() print us a nice
                         * error.
                         */
                        if (perf_missing_features.clockid ||
                            perf_missing_features.clockid_wrong) {
                                err = -EINVAL;
                                goto out_close;
                        }
                }
        }

        return 0;

try_fallback:
        /*
         * perf stat needs between 5 and 22 fds per CPU. When we run out
         * of them try to increase the limits.
         */
        if (err == -EMFILE && set_rlimit < INCREASED_MAX) {
                struct rlimit l;
                int old_errno = errno;

                if (getrlimit(RLIMIT_NOFILE, &l) == 0) {
                        if (set_rlimit == NO_CHANGE)
                                l.rlim_cur = l.rlim_max;
                        else {
                                l.rlim_cur = l.rlim_max + 1000;
                                l.rlim_max = l.rlim_cur;
                        }
                        if (setrlimit(RLIMIT_NOFILE, &l) == 0) {
                                set_rlimit++;
                                errno = old_errno;
                                goto retry_open;
                        }
                }
                errno = old_errno;
        }

        if (err != -EINVAL || cpu > 0 || thread > 0)
                goto out_close;

        /*
         * Must probe features in the order they were added to the
         * perf_event_attr interface.
         */
        if (!perf_missing_features.aux_output && evsel->core.attr.aux_output) {
                perf_missing_features.aux_output = true;
                pr_debug2("Kernel has no attr.aux_output support, bailing out\n");
                goto out_close;
        } else if (!perf_missing_features.bpf && evsel->core.attr.bpf_event) {
                perf_missing_features.bpf = true;
                pr_debug2("switching off bpf_event\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.ksymbol && evsel->core.attr.ksymbol) {
                perf_missing_features.ksymbol = true;
                pr_debug2("switching off ksymbol\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.write_backward && evsel->core.attr.write_backward) {
                perf_missing_features.write_backward = true;
                pr_debug2("switching off write_backward\n");
                goto out_close;
        } else if (!perf_missing_features.clockid_wrong && evsel->core.attr.use_clockid) {
                perf_missing_features.clockid_wrong = true;
                pr_debug2("switching off clockid\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.clockid && evsel->core.attr.use_clockid) {
                perf_missing_features.clockid = true;
                pr_debug2("switching off use_clockid\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.cloexec && (flags & PERF_FLAG_FD_CLOEXEC)) {
                perf_missing_features.cloexec = true;
                pr_debug2("switching off cloexec flag\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.mmap2 && evsel->core.attr.mmap2) {
                perf_missing_features.mmap2 = true;
                pr_debug2("switching off mmap2\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.exclude_guest &&
                   (evsel->core.attr.exclude_guest || evsel->core.attr.exclude_host)) {
                perf_missing_features.exclude_guest = true;
                pr_debug2("switching off exclude_guest, exclude_host\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.sample_id_all) {
                perf_missing_features.sample_id_all = true;
                pr_debug2("switching off sample_id_all\n");
                goto retry_sample_id;
        } else if (!perf_missing_features.lbr_flags &&
                        (evsel->core.attr.branch_sample_type &
                         (PERF_SAMPLE_BRANCH_NO_CYCLES |
                          PERF_SAMPLE_BRANCH_NO_FLAGS))) {
                perf_missing_features.lbr_flags = true;
                pr_debug2("switching off branch sample type no (cycles/flags)\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.group_read &&
                    evsel->core.attr.inherit &&
                   (evsel->core.attr.read_format & PERF_FORMAT_GROUP) &&
                   perf_evsel__is_group_leader(evsel)) {
                perf_missing_features.group_read = true;
                pr_debug2("switching off group read\n");
                goto fallback_missing_features;
        }
out_close:
        if (err)
                threads->err_thread = thread;

        do {
                while (--thread >= 0) {
                        close(FD(evsel, cpu, thread));
                        FD(evsel, cpu, thread) = -1;
                }
                thread = nthreads;
        } while (--cpu >= 0);
        return err;
}

void evsel__close(struct evsel *evsel)
{
        perf_evsel__close(&evsel->core);
        perf_evsel__free_id(&evsel->core);
}

int perf_evsel__open_per_cpu(struct evsel *evsel,
                             struct perf_cpu_map *cpus)
{
        return evsel__open(evsel, cpus, NULL);
}

int perf_evsel__open_per_thread(struct evsel *evsel,
                                struct perf_thread_map *threads)
{
        return evsel__open(evsel, NULL, threads);
}

static int perf_evsel__parse_id_sample(const struct evsel *evsel,
                                       const union perf_event *event,
                                       struct perf_sample *sample)
{
        u64 type = evsel->core.attr.sample_type;
        const __u64 *array = event->sample.array;
        bool swapped = evsel->needs_swap;
        union u64_swap u;

        array += ((event->header.size -
                   sizeof(event->header)) / sizeof(u64)) - 1;

        if (type & PERF_SAMPLE_IDENTIFIER) {
                sample->id = *array;
                array--;
        }

        if (type & PERF_SAMPLE_CPU) {
                u.val64 = *array;
                if (swapped) {
                        /* undo swap of u64, then swap on individual u32s */
                        u.val64 = bswap_64(u.val64);
                        u.val32[0] = bswap_32(u.val32[0]);
                }

                sample->cpu = u.val32[0];
                array--;
        }

        if (type & PERF_SAMPLE_STREAM_ID) {
                sample->stream_id = *array;
                array--;
        }

        if (type & PERF_SAMPLE_ID) {
                sample->id = *array;
                array--;
        }

        if (type & PERF_SAMPLE_TIME) {
                sample->time = *array;
                array--;
        }

        if (type & PERF_SAMPLE_TID) {
                u.val64 = *array;
                if (swapped) {
                        /* undo swap of u64, then swap on individual u32s */
                        u.val64 = bswap_64(u.val64);
                        u.val32[0] = bswap_32(u.val32[0]);
                        u.val32[1] = bswap_32(u.val32[1]);
                }

                sample->pid = u.val32[0];
                sample->tid = u.val32[1];
                array--;
        }

        return 0;
}

static inline bool overflow(const void *endp, u16 max_size, const void *offset,
                            u64 size)
{
        return size > max_size || offset + size > endp;
}

#define OVERFLOW_CHECK(offset, size, max_size)                          \
        do {                                                            \
                if (overflow(endp, (max_size), (offset), (size)))       \
                        return -EFAULT;                                 \
        } while (0)

#define OVERFLOW_CHECK_u64(offset) \
        OVERFLOW_CHECK(offset, sizeof(u64), sizeof(u64))

static int
perf_event__check_size(union perf_event *event, unsigned int sample_size)
{
        /*
         * The evsel's sample_size is based on PERF_SAMPLE_MASK which includes
         * up to PERF_SAMPLE_PERIOD.  After that overflow() must be used to
         * check the format does not go past the end of the event.
         */
        if (sample_size + sizeof(event->header) > event->header.size)
                return -EFAULT;

        return 0;
}

int perf_evsel__parse_sample(struct evsel *evsel, union perf_event *event,
                             struct perf_sample *data)
{
        u64 type = evsel->core.attr.sample_type;
        bool swapped = evsel->needs_swap;
        const __u64 *array;
        u16 max_size = event->header.size;
        const void *endp = (void *)event + max_size;
        u64 sz;

        /*
         * used for cross-endian analysis. See git commit 65014ab3
         * for why this goofiness is needed.
         */
        union u64_swap u;

        memset(data, 0, sizeof(*data));
        data->cpu = data->pid = data->tid = -1;
        data->stream_id = data->id = data->time = -1ULL;
        data->period = evsel->core.attr.sample_period;
        data->cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
        data->misc    = event->header.misc;
        data->id = -1ULL;
        data->data_src = PERF_MEM_DATA_SRC_NONE;

        if (event->header.type != PERF_RECORD_SAMPLE) {
                if (!evsel->core.attr.sample_id_all)
                        return 0;
                return perf_evsel__parse_id_sample(evsel, event, data);
        }

        array = event->sample.array;

        if (perf_event__check_size(event, evsel->sample_size))
                return -EFAULT;

        if (type & PERF_SAMPLE_IDENTIFIER) {
                data->id = *array;
                array++;
        }

        if (type & PERF_SAMPLE_IP) {
                data->ip = *array;
                array++;
        }

        if (type & PERF_SAMPLE_TID) {
                u.val64 = *array;
                if (swapped) {
                        /* undo swap of u64, then swap on individual u32s */
                        u.val64 = bswap_64(u.val64);
                        u.val32[0] = bswap_32(u.val32[0]);
                        u.val32[1] = bswap_32(u.val32[1]);
                }

                data->pid = u.val32[0];
                data->tid = u.val32[1];
                array++;
        }

        if (type & PERF_SAMPLE_TIME) {
                data->time = *array;
                array++;
        }

        if (type & PERF_SAMPLE_ADDR) {
                data->addr = *array;
                array++;

        }

        if (type & PERF_SAMPLE_ID) {
                data->id = *array;
                array++;
        }

        if (type & PERF_SAMPLE_STREAM_ID) {
                data->stream_id = *array;
                array++;
        }

        if (type & PERF_SAMPLE_CPU) {

                u.val64 = *array;
                if (swapped) {
                        /* undo swap of u64, then swap on individual u32s */
                        u.val64 = bswap_64(u.val64);
                        u.val32[0] = bswap_32(u.val32[0]);
                }

                data->cpu = u.val32[0];
                array++;
        }

        if (type & PERF_SAMPLE_PERIOD) {
                data->period = *array;
                array++;
        }

        if (type & PERF_SAMPLE_READ) {
                u64 read_format = evsel->core.attr.read_format;

                OVERFLOW_CHECK_u64(array);
                if (read_format & PERF_FORMAT_GROUP)
                        data->read.group.nr = *array;
                else
                        data->read.one.value = *array;

                array++;

                if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
                        OVERFLOW_CHECK_u64(array);
                        data->read.time_enabled = *array;
                        array++;
                }

                if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
                        OVERFLOW_CHECK_u64(array);
                        data->read.time_running = *array;
                        array++;
                }

                /* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
                if (read_format & PERF_FORMAT_GROUP) {
                        const u64 max_group_nr = UINT64_MAX /
                                        sizeof(struct sample_read_value);

                        if (data->read.group.nr > max_group_nr)
                                return -EFAULT;
                        sz = data->read.group.nr *
                             sizeof(struct sample_read_value);
                        OVERFLOW_CHECK(array, sz, max_size);
                        data->read.group.values =
                                        (struct sample_read_value *)array;
                        array = (void *)array + sz;
                } else {
                        OVERFLOW_CHECK_u64(array);
                        data->read.one.id = *array;
                        array++;
                }
        }

        if (evsel__has_callchain(evsel)) {
                const u64 max_callchain_nr = UINT64_MAX / sizeof(u64);

                OVERFLOW_CHECK_u64(array);
                data->callchain = (struct ip_callchain *)array++;
                if (data->callchain->nr > max_callchain_nr)
                        return -EFAULT;
                sz = data->callchain->nr * sizeof(u64);
                OVERFLOW_CHECK(array, sz, max_size);
                array = (void *)array + sz;
        }

        if (type & PERF_SAMPLE_RAW) {
                OVERFLOW_CHECK_u64(array);
                u.val64 = *array;

                /*
                 * Undo swap of u64, then swap on individual u32s,
                 * get the size of the raw area and undo all of the
                 * swap. The pevent interface handles endianity by
                 * itself.
                 */
                if (swapped) {
                        u.val64 = bswap_64(u.val64);
                        u.val32[0] = bswap_32(u.val32[0]);
                        u.val32[1] = bswap_32(u.val32[1]);
                }
                data->raw_size = u.val32[0];

                /*
                 * The raw data is aligned on 64bits including the
                 * u32 size, so it's safe to use mem_bswap_64.
                 */
                if (swapped)
                        mem_bswap_64((void *) array, data->raw_size);

                array = (void *)array + sizeof(u32);

                OVERFLOW_CHECK(array, data->raw_size, max_size);
                data->raw_data = (void *)array;
                array = (void *)array + data->raw_size;
        }

        if (type & PERF_SAMPLE_BRANCH_STACK) {
                const u64 max_branch_nr = UINT64_MAX /
                                          sizeof(struct branch_entry);

                OVERFLOW_CHECK_u64(array);
                data->branch_stack = (struct branch_stack *)array++;

                if (data->branch_stack->nr > max_branch_nr)
                        return -EFAULT;
                sz = data->branch_stack->nr * sizeof(struct branch_entry);
                OVERFLOW_CHECK(array, sz, max_size);
                array = (void *)array + sz;
        }

        if (type & PERF_SAMPLE_REGS_USER) {
                OVERFLOW_CHECK_u64(array);
                data->user_regs.abi = *array;
                array++;

                if (data->user_regs.abi) {
                        u64 mask = evsel->core.attr.sample_regs_user;

                        sz = hweight64(mask) * sizeof(u64);
                        OVERFLOW_CHECK(array, sz, max_size);
                        data->user_regs.mask = mask;
                        data->user_regs.regs = (u64 *)array;
                        array = (void *)array + sz;
                }
        }

        if (type & PERF_SAMPLE_STACK_USER) {
                OVERFLOW_CHECK_u64(array);
                sz = *array++;

                data->user_stack.offset = ((char *)(array - 1)
                                          - (char *) event);

                if (!sz) {
                        data->user_stack.size = 0;
                } else {
                        OVERFLOW_CHECK(array, sz, max_size);
                        data->user_stack.data = (char *)array;
                        array = (void *)array + sz;
                        OVERFLOW_CHECK_u64(array);
                        data->user_stack.size = *array++;
                        if (WARN_ONCE(data->user_stack.size > sz,
                                      "user stack dump failure\n"))
                                return -EFAULT;
                }
        }

        if (type & PERF_SAMPLE_WEIGHT) {
                OVERFLOW_CHECK_u64(array);
                data->weight = *array;
                array++;
        }

        if (type & PERF_SAMPLE_DATA_SRC) {
                OVERFLOW_CHECK_u64(array);
                data->data_src = *array;
                array++;
        }

        if (type & PERF_SAMPLE_TRANSACTION) {
                OVERFLOW_CHECK_u64(array);
                data->transaction = *array;
                array++;
        }

        data->intr_regs.abi = PERF_SAMPLE_REGS_ABI_NONE;
        if (type & PERF_SAMPLE_REGS_INTR) {
                OVERFLOW_CHECK_u64(array);
                data->intr_regs.abi = *array;
                array++;

                if (data->intr_regs.abi != PERF_SAMPLE_REGS_ABI_NONE) {
                        u64 mask = evsel->core.attr.sample_regs_intr;

                        sz = hweight64(mask) * sizeof(u64);
                        OVERFLOW_CHECK(array, sz, max_size);
                        data->intr_regs.mask = mask;
                        data->intr_regs.regs = (u64 *)array;
                        array = (void *)array + sz;
                }
        }

        data->phys_addr = 0;
        if (type & PERF_SAMPLE_PHYS_ADDR) {
                data->phys_addr = *array;
                array++;
        }

        return 0;
}

int perf_evsel__parse_sample_timestamp(struct evsel *evsel,
                                       union perf_event *event,
                                       u64 *timestamp)
{
        u64 type = evsel->core.attr.sample_type;
        const __u64 *array;

        if (!(type & PERF_SAMPLE_TIME))
                return -1;

        if (event->header.type != PERF_RECORD_SAMPLE) {
                struct perf_sample data = {
                        .time = -1ULL,
                };

                if (!evsel->core.attr.sample_id_all)
                        return -1;
                if (perf_evsel__parse_id_sample(evsel, event, &data))
                        return -1;

                *timestamp = data.time;
                return 0;
        }

        array = event->sample.array;

        if (perf_event__check_size(event, evsel->sample_size))
                return -EFAULT;

        if (type & PERF_SAMPLE_IDENTIFIER)
                array++;

        if (type & PERF_SAMPLE_IP)
                array++;

        if (type & PERF_SAMPLE_TID)
                array++;

        if (type & PERF_SAMPLE_TIME)
                *timestamp = *array;

        return 0;
}

struct tep_format_field *perf_evsel__field(struct evsel *evsel, const char *name)
{
        return tep_find_field(evsel->tp_format, name);
}

void *perf_evsel__rawptr(struct evsel *evsel, struct perf_sample *sample,
                         const char *name)
{
        struct tep_format_field *field = perf_evsel__field(evsel, name);
        int offset;

        if (!field)
                return NULL;

        offset = field->offset;

        if (field->flags & TEP_FIELD_IS_DYNAMIC) {
                offset = *(int *)(sample->raw_data + field->offset);
                offset &= 0xffff;
        }

        return sample->raw_data + offset;
}

u64 format_field__intval(struct tep_format_field *field, struct perf_sample *sample,
                         bool needs_swap)
{
        u64 value;
        void *ptr = sample->raw_data + field->offset;

        switch (field->size) {
        case 1:
                return *(u8 *)ptr;
        case 2:
                value = *(u16 *)ptr;
                break;
        case 4:
                value = *(u32 *)ptr;
                break;
        case 8:
                memcpy(&value, ptr, sizeof(u64));
                break;
        default:
                return 0;
        }

        if (!needs_swap)
                return value;

        switch (field->size) {
        case 2:
                return bswap_16(value);
        case 4:
                return bswap_32(value);
        case 8:
                return bswap_64(value);
        default:
                return 0;
        }

        return 0;
}

u64 perf_evsel__intval(struct evsel *evsel, struct perf_sample *sample,
                       const char *name)
{
        struct tep_format_field *field = perf_evsel__field(evsel, name);

        if (!field)
                return 0;

        return field ? format_field__intval(field, sample, evsel->needs_swap) : 0;
}

bool perf_evsel__fallback(struct evsel *evsel, int err,
                          char *msg, size_t msgsize)
{
        int paranoid;

        if ((err == ENOENT || err == ENXIO || err == ENODEV) &&
            evsel->core.attr.type   == PERF_TYPE_HARDWARE &&
            evsel->core.attr.config == PERF_COUNT_HW_CPU_CYCLES) {
                /*
                 * If it's cycles then fall back to hrtimer based
                 * cpu-clock-tick sw counter, which is always available even if
                 * no PMU support.
                 *
                 * PPC returns ENXIO until 2.6.37 (behavior changed with commit
                 * b0a873e).
                 */
                scnprintf(msg, msgsize, "%s",
"The cycles event is not supported, trying to fall back to cpu-clock-ticks");

                evsel->core.attr.type   = PERF_TYPE_SOFTWARE;
                evsel->core.attr.config = PERF_COUNT_SW_CPU_CLOCK;

                zfree(&evsel->name);
                return true;
        } else if (err == EACCES && !evsel->core.attr.exclude_kernel &&
                   (paranoid = perf_event_paranoid()) > 1) {
                const char *name = perf_evsel__name(evsel);
                char *new_name;
                const char *sep = ":";

                /* Is there already the separator in the name. */
                if (strchr(name, '/') ||
                    strchr(name, ':'))
                        sep = "";

                if (asprintf(&new_name, "%s%su", name, sep) < 0)
                        return false;

                if (evsel->name)
                        free(evsel->name);
                evsel->name = new_name;
                scnprintf(msg, msgsize, "kernel.perf_event_paranoid=%d, trying "
                          "to fall back to excluding kernel and hypervisor "
                          " samples", paranoid);
                evsel->core.attr.exclude_kernel = 1;
                evsel->core.attr.exclude_hv     = 1;

                return true;
        }

        return false;
}

static bool find_process(const char *name)
{
        size_t len = strlen(name);
        DIR *dir;
        struct dirent *d;
        int ret = -1;

        dir = opendir(procfs__mountpoint());
        if (!dir)
                return false;

        /* Walk through the directory. */
        while (ret && (d = readdir(dir)) != NULL) {
                char path[PATH_MAX];
                char *data;
                size_t size;

                if ((d->d_type != DT_DIR) ||
                     !strcmp(".", d->d_name) ||
                     !strcmp("..", d->d_name))
                        continue;

                scnprintf(path, sizeof(path), "%s/%s/comm",
                          procfs__mountpoint(), d->d_name);

                if (filename__read_str(path, &data, &size))
                        continue;

                ret = strncmp(name, data, len);
                free(data);
        }

        closedir(dir);
        return ret ? false : true;
}

int perf_evsel__open_strerror(struct evsel *evsel, struct target *target,
                              int err, char *msg, size_t size)
{
        char sbuf[STRERR_BUFSIZE];
        int printed = 0;

        switch (err) {
        case EPERM:
        case EACCES:
                if (err == EPERM)
                        printed = scnprintf(msg, size,
                                "No permission to enable %s event.\n\n",
                                perf_evsel__name(evsel));

                return scnprintf(msg + printed, size - printed,
                 "You may not have permission to collect %sstats.\n\n"
                 "Consider tweaking /proc/sys/kernel/perf_event_paranoid,\n"
                 "which controls use of the performance events system by\n"
                 "unprivileged users (without CAP_SYS_ADMIN).\n\n"
                 "The current value is %d:\n\n"
                 "  -1: Allow use of (almost) all events by all users\n"
                 "      Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n"
                 ">= 0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN\n"
                 "      Disallow raw tracepoint access by users without CAP_SYS_ADMIN\n"
                 ">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n"
                 ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN\n\n"
                 "To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n"
                 "      kernel.perf_event_paranoid = -1\n" ,
                                 target->system_wide ? "system-wide " : "",
                                 perf_event_paranoid());
        case ENOENT:
                return scnprintf(msg, size, "The %s event is not supported.",
                                 perf_evsel__name(evsel));
        case EMFILE:
                return scnprintf(msg, size, "%s",
                         "Too many events are opened.\n"
                         "Probably the maximum number of open file descriptors has been reached.\n"
                         "Hint: Try again after reducing the number of events.\n"
                         "Hint: Try increasing the limit with 'ulimit -n <limit>'");
        case ENOMEM:
                if (evsel__has_callchain(evsel) &&
                    access("/proc/sys/kernel/perf_event_max_stack", F_OK) == 0)
                        return scnprintf(msg, size,
                                         "Not enough memory to setup event with callchain.\n"
                                         "Hint: Try tweaking /proc/sys/kernel/perf_event_max_stack\n"
                                         "Hint: Current value: %d", sysctl__max_stack());
                break;
        case ENODEV:
                if (target->cpu_list)
                        return scnprintf(msg, size, "%s",
         "No such device - did you specify an out-of-range profile CPU?");
                break;
        case EOPNOTSUPP:
                if (evsel->core.attr.sample_period != 0)
                        return scnprintf(msg, size,
        "%s: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'",
                                         perf_evsel__name(evsel));
                if (evsel->core.attr.precise_ip)
                        return scnprintf(msg, size, "%s",
        "\'precise\' request may not be supported. Try removing 'p' modifier.");
#if defined(__i386__) || defined(__x86_64__)
                if (evsel->core.attr.type == PERF_TYPE_HARDWARE)
                        return scnprintf(msg, size, "%s",
        "No hardware sampling interrupt available.\n");
#endif
                break;
        case EBUSY:
                if (find_process("oprofiled"))
                        return scnprintf(msg, size,
        "The PMU counters are busy/taken by another profiler.\n"
        "We found oprofile daemon running, please stop it and try again.");
                break;
        case EINVAL:
                if (evsel->core.attr.write_backward && perf_missing_features.write_backward)
                        return scnprintf(msg, size, "Reading from overwrite event is not supported by this kernel.");
                if (perf_missing_features.clockid)
                        return scnprintf(msg, size, "clockid feature not supported.");
                if (perf_missing_features.clockid_wrong)
                        return scnprintf(msg, size, "wrong clockid (%d).", clockid);
                if (perf_missing_features.aux_output)
                        return scnprintf(msg, size, "The 'aux_output' feature is not supported, update the kernel.");
                break;
        default:
                break;
        }

        return scnprintf(msg, size,
        "The sys_perf_event_open() syscall returned with %d (%s) for event (%s).\n"
        "/bin/dmesg | grep -i perf may provide additional information.\n",
                         err, str_error_r(err, sbuf, sizeof(sbuf)),
                         perf_evsel__name(evsel));
}

struct perf_env *perf_evsel__env(struct evsel *evsel)
{
        if (evsel && evsel->evlist)
                return evsel->evlist->env;
        return &perf_env;
}

static int store_evsel_ids(struct evsel *evsel, struct evlist *evlist)
{
        int cpu, thread;

        for (cpu = 0; cpu < xyarray__max_x(evsel->core.fd); cpu++) {
                for (thread = 0; thread < xyarray__max_y(evsel->core.fd);
                     thread++) {
                        int fd = FD(evsel, cpu, thread);

                        if (perf_evlist__id_add_fd(&evlist->core, &evsel->core,
                                                   cpu, thread, fd) < 0)
                                return -1;
                }
        }

        return 0;
}

int perf_evsel__store_ids(struct evsel *evsel, struct evlist *evlist)
{
        struct perf_cpu_map *cpus = evsel->core.cpus;
        struct perf_thread_map *threads = evsel->core.threads;

        if (perf_evsel__alloc_id(&evsel->core, cpus->nr, threads->nr))
                return -ENOMEM;

        return store_evsel_ids(evsel, evlist);
}