// SPDX-License-Identifier: GPL-2.0
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
#include "dso.h"
#include "session.h"
#include "thread.h"
#include "thread-stack.h"
#include "debug.h"
#include "namespaces.h"
#include "comm.h"
#include "map.h"
#include "symbol.h"
#include "unwind.h"
#include "callchain.h"
#include "dwarf-regs.h"

#include <api/fs/fs.h>

int thread__init_maps(struct thread *thread, struct machine *machine)
{
        pid_t pid = thread__pid(thread);

        if (pid == thread__tid(thread) || pid == -1) {
                thread__set_maps(thread, maps__new(machine));
        } else {
                struct thread *leader = machine__findnew_thread(machine, pid, pid);

                if (leader) {
                        thread__set_maps(thread, maps__get(thread__maps(leader)));
                        thread__put(leader);
                }
        }

        return thread__maps(thread) ? 0 : -1;
}

struct thread *thread__new(pid_t pid, pid_t tid)
        NO_THREAD_SAFETY_ANALYSIS /* Allocation/creation is inherently single threaded. */
{
        RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread));
        struct thread *thread;

        if (ADD_RC_CHK(thread, _thread) != NULL) {
                struct comm *comm;
                char comm_str[32];

                thread__set_pid(thread, pid);
                thread__set_tid(thread, tid);
                thread__set_ppid(thread, -1);
                thread__set_cpu(thread, -1);
                thread__set_guest_cpu(thread, -1);
                thread__set_e_machine(thread, EM_NONE);
                thread__set_lbr_stitch_enable(thread, false);
                INIT_LIST_HEAD(thread__namespaces_list(thread));
                INIT_LIST_HEAD(thread__comm_list(thread));
                init_rwsem(thread__namespaces_lock(thread));
                init_rwsem(thread__comm_lock(thread));

                snprintf(comm_str, sizeof(comm_str), ":%d", tid);
                comm = comm__new(comm_str, 0, false);
                if (!comm)
                        goto err_thread;

                list_add(&comm->list, thread__comm_list(thread));
                refcount_set(thread__refcnt(thread), 1);
                /* Thread holds first ref to nsdata. */
                RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new(pid);
                srccode_state_init(thread__srccode_state(thread));
        }

        return thread;

err_thread:
        thread__delete(thread);
        return NULL;
}

static void (*thread__priv_destructor)(void *priv);

void thread__set_priv_destructor(void (*destructor)(void *priv))
{
        assert(thread__priv_destructor == NULL);

        thread__priv_destructor = destructor;
}

void thread__delete(struct thread *thread)
{
        struct namespaces *namespaces, *tmp_namespaces;
        struct comm *comm, *tmp_comm;

        thread_stack__free(thread);

        if (thread__maps(thread)) {
                maps__put(thread__maps(thread));
                thread__set_maps(thread, NULL);
        }
        down_write(thread__namespaces_lock(thread));
        list_for_each_entry_safe(namespaces, tmp_namespaces,
                                 thread__namespaces_list(thread), list) {
                list_del_init(&namespaces->list);
                namespaces__free(namespaces);
        }
        up_write(thread__namespaces_lock(thread));

        down_write(thread__comm_lock(thread));
        list_for_each_entry_safe(comm, tmp_comm, thread__comm_list(thread), list) {
                list_del_init(&comm->list);
                comm__free(comm);
        }
        up_write(thread__comm_lock(thread));

        nsinfo__zput(RC_CHK_ACCESS(thread)->nsinfo);
        srccode_state_free(thread__srccode_state(thread));

        exit_rwsem(thread__namespaces_lock(thread));
        exit_rwsem(thread__comm_lock(thread));
        thread__free_stitch_list(thread);

        if (thread__priv_destructor)
                thread__priv_destructor(thread__priv(thread));

        RC_CHK_FREE(thread);
}

struct thread *thread__get(struct thread *thread)
{
        struct thread *result;

        if (RC_CHK_GET(result, thread))
                refcount_inc(thread__refcnt(thread));

        return result;
}

void thread__put(struct thread *thread)
{
        if (thread && refcount_dec_and_test(thread__refcnt(thread)))
                thread__delete(thread);
        else
                RC_CHK_PUT(thread);
}

static struct namespaces *__thread__namespaces(struct thread *thread)
{
        if (list_empty(thread__namespaces_list(thread)))
                return NULL;

        return list_first_entry(thread__namespaces_list(thread), struct namespaces, list);
}

struct namespaces *thread__namespaces(struct thread *thread)
{
        struct namespaces *ns;

        down_read(thread__namespaces_lock(thread));
        ns = __thread__namespaces(thread);
        up_read(thread__namespaces_lock(thread));

        return ns;
}

static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
                                    struct perf_record_namespaces *event)
{
        struct namespaces *new, *curr = __thread__namespaces(thread);

        new = namespaces__new(event);
        if (!new)
                return -ENOMEM;

        list_add(&new->list, thread__namespaces_list(thread));

        if (timestamp && curr) {
                /*
                 * setns syscall must have changed few or all the namespaces
                 * of this thread. Update end time for the namespaces
                 * previously used.
                 */
                curr = list_next_entry(new, list);
                curr->end_time = timestamp;
        }

        return 0;
}

int thread__set_namespaces(struct thread *thread, u64 timestamp,
                           struct perf_record_namespaces *event)
{
        int ret;

        down_write(thread__namespaces_lock(thread));
        ret = __thread__set_namespaces(thread, timestamp, event);
        up_write(thread__namespaces_lock(thread));
        return ret;
}

static struct comm *__thread__comm(struct thread *thread)
        SHARED_LOCKS_REQUIRED(thread__comm_lock(thread))
{
        if (list_empty(thread__comm_list(thread)))
                return NULL;

        return list_first_entry(thread__comm_list(thread), struct comm, list);
}

struct comm *thread__comm(struct thread *thread)
{
        struct comm *res = NULL;

        down_read(thread__comm_lock(thread));
        res = __thread__comm(thread);
        up_read(thread__comm_lock(thread));
        return res;
}

struct comm *thread__exec_comm(struct thread *thread)
{
        struct comm *comm, *last = NULL, *second_last = NULL;

        down_read(thread__comm_lock(thread));
        list_for_each_entry(comm, thread__comm_list(thread), list) {
                if (comm->exec) {
                        up_read(thread__comm_lock(thread));
                        return comm;
                }
                second_last = last;
                last = comm;
        }
        up_read(thread__comm_lock(thread));

        /*
         * 'last' with no start time might be the parent's comm of a synthesized
         * thread (created by processing a synthesized fork event). For a main
         * thread, that is very probably wrong. Prefer a later comm to avoid
         * that case.
         */
        if (second_last && !last->start && thread__pid(thread) == thread__tid(thread))
                return second_last;

        return last;
}

static int ____thread__set_comm(struct thread *thread, const char *str,
                                u64 timestamp, bool exec)
        EXCLUSIVE_LOCKS_REQUIRED(thread__comm_lock(thread))
{
        struct comm *new, *curr = __thread__comm(thread);

        /* Override the default :tid entry */
        if (!thread__comm_set(thread)) {
                int err = comm__override(curr, str, timestamp, exec);
                if (err)
                        return err;
        } else {
                new = comm__new(str, timestamp, exec);
                if (!new)
                        return -ENOMEM;
                list_add(&new->list, thread__comm_list(thread));

                if (exec)
                        unwind__flush_access(thread__maps(thread));
        }

        thread__set_comm_set(thread, true);

        return 0;
}

int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
                       bool exec)
{
        int ret;

        down_write(thread__comm_lock(thread));
        ret = ____thread__set_comm(thread, str, timestamp, exec);
        up_write(thread__comm_lock(thread));
        return ret;
}

int thread__set_comm_from_proc(struct thread *thread)
{
        char path[64];
        char *comm = NULL;
        size_t sz;
        int err = -1;

        if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
                       thread__pid(thread), thread__tid(thread)) >= (int)sizeof(path)) &&
            procfs__read_str(path, &comm, &sz) == 0) {
                comm[sz - 1] = '\0';
                err = thread__set_comm(thread, comm, 0);
        }

        return err;
}

static const char *__thread__comm_str(struct thread *thread)
        SHARED_LOCKS_REQUIRED(thread__comm_lock(thread))
{
        const struct comm *comm = __thread__comm(thread);

        if (!comm)
                return NULL;

        return comm__str(comm);
}

const char *thread__comm_str(struct thread *thread)
{
        const char *str;

        down_read(thread__comm_lock(thread));
        str = __thread__comm_str(thread);
        up_read(thread__comm_lock(thread));

        return str;
}

static int __thread__comm_len(struct thread *thread, const char *comm)
{
        if (!comm)
                return 0;
        thread__set_comm_len(thread, strlen(comm));

        return thread__var_comm_len(thread);
}

/* CHECKME: it should probably better return the max comm len from its comm list */
int thread__comm_len(struct thread *thread)
{
        int comm_len = thread__var_comm_len(thread);

        if (!comm_len) {
                const char *comm;

                down_read(thread__comm_lock(thread));
                comm = __thread__comm_str(thread);
                comm_len = __thread__comm_len(thread, comm);
                up_read(thread__comm_lock(thread));
        }

        return comm_len;
}

size_t thread__fprintf(struct thread *thread, FILE *fp)
{
        return fprintf(fp, "Thread %d %s\n", thread__tid(thread), thread__comm_str(thread)) +
               maps__fprintf(thread__maps(thread), fp);
}

int thread__insert_map(struct thread *thread, struct map *map)
{
        int ret;

        ret = unwind__prepare_access(thread__maps(thread), map, NULL);
        if (ret)
                return ret;

        return maps__fixup_overlap_and_insert(thread__maps(thread), map);
}

struct thread__prepare_access_maps_cb_args {
        int err;
        struct maps *maps;
};

static int thread__prepare_access_maps_cb(struct map *map, void *data)
{
        bool initialized = false;
        struct thread__prepare_access_maps_cb_args *args = data;

        args->err = unwind__prepare_access(args->maps, map, &initialized);

        return (args->err || initialized) ? 1 : 0;
}

static int thread__prepare_access(struct thread *thread)
{
        struct thread__prepare_access_maps_cb_args args = {
                .err = 0,
        };

        if (dwarf_callchain_users) {
                args.maps = thread__maps(thread);
                maps__for_each_map(thread__maps(thread), thread__prepare_access_maps_cb, &args);
        }

        return args.err;
}

static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone)
{
        /* This is new thread, we share map groups for process. */
        if (thread__pid(thread) == thread__pid(parent))
                return thread__prepare_access(thread);

        if (maps__equal(thread__maps(thread), thread__maps(parent))) {
                pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
                         thread__pid(thread), thread__tid(thread),
                         thread__pid(parent), thread__tid(parent));
                return 0;
        }
        /* But this one is new process, copy maps. */
        return do_maps_clone ? maps__copy_from(thread__maps(thread), thread__maps(parent)) : 0;
}

int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
{
        if (thread__comm_set(parent)) {
                const char *comm = thread__comm_str(parent);
                int err;
                if (!comm)
                        return -ENOMEM;
                err = thread__set_comm(thread, comm, timestamp);
                if (err)
                        return err;
        }

        thread__set_ppid(thread, thread__tid(parent));
        return thread__clone_maps(thread, parent, do_maps_clone);
}

void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
                                        bool symbols, struct addr_location *al)
{
        size_t i;
        const u8 cpumodes[] = {
                PERF_RECORD_MISC_USER,
                PERF_RECORD_MISC_KERNEL,
                PERF_RECORD_MISC_GUEST_USER,
                PERF_RECORD_MISC_GUEST_KERNEL
        };

        for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
                if (symbols)
                        thread__find_symbol(thread, cpumodes[i], addr, al);
                else
                        thread__find_map(thread, cpumodes[i], addr, al);

                if (al->map)
                        break;
        }
}

static uint16_t read_proc_e_machine_for_pid(pid_t pid, uint32_t *e_flags)
{
        char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" */];
        int fd;
        uint16_t e_machine = EM_NONE;

        snprintf(path, sizeof(path), "/proc/%d/exe", pid);
        fd = open(path, O_RDONLY);
        if (fd >= 0) {
                e_machine = dso__read_e_machine(/*optional_dso=*/NULL, fd, e_flags);
                close(fd);
        }
        return e_machine;
}

struct thread__e_machine_callback_args {
        struct machine *machine;
        uint32_t e_flags;
        uint16_t e_machine;
};

static int thread__e_machine_callback(struct map *map, void *_args)
{
        struct thread__e_machine_callback_args *args = _args;
        struct dso *dso = map__dso(map);

        if (!dso)
                return 0; // No dso, continue search.

        args->e_machine = dso__e_machine(dso, args->machine, &args->e_flags);
        return args->e_machine != EM_NONE ? 1 /* stop search */ : 0 /* continue search */;
}

uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint32_t *e_flags)
{
        pid_t tid, pid;
        uint16_t e_machine = RC_CHK_ACCESS(thread)->e_machine;
        uint32_t local_e_flags = 0;
        struct thread__e_machine_callback_args args = {
                .machine = machine,
                .e_flags = 0,
                .e_machine = EM_NONE,
        };

        if (e_machine != EM_NONE) {
                if (e_flags)
                        *e_flags = thread__e_flags(thread);
                return e_machine;
        }

        if (machine == NULL) {
                struct maps *maps = thread__maps(thread);

                machine = maps__machine(maps);
        }
        tid = thread__tid(thread);
        pid = thread__pid(thread);
        if (pid != tid) {
                struct thread *parent = machine__findnew_thread(machine, pid, pid);

                if (parent) {
                        e_machine = thread__e_machine(parent, machine, &local_e_flags);
                        thread__put(parent);
                        goto out;
                }
                /* Something went wrong, fallback. */
        }
        /* Reading on the PID thread. First try to find from the maps. */
        maps__for_each_map(thread__maps(thread), thread__e_machine_callback, &args);

        if (args.e_machine != EM_NONE) {
                e_machine = args.e_machine;
                local_e_flags = args.e_flags;
        } else {
                /* Maps failed, perhaps we're live with map events disabled. */
                bool is_live = machine->machines == NULL;

                if (!is_live) {
                        /* Check if the session has a data file. */
                        struct perf_session *session = container_of(machine->machines,
                                                                    struct perf_session,
                                                                    machines);

                        is_live = !!session->data;
                }
                /* Read from /proc/pid/exe if live. */
                if (is_live)
                        e_machine = read_proc_e_machine_for_pid(pid, &local_e_flags);
        }
out:
        if (e_machine != EM_NONE) {
                thread__set_e_machine(thread, e_machine);
                thread__set_e_flags(thread, local_e_flags);
        } else {
                e_machine = EM_HOST;
                local_e_flags = EF_HOST;
        }
        if (e_flags)
                *e_flags = local_e_flags;
        return e_machine;
}

struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
{
        if (thread__pid(thread) == thread__tid(thread))
                return thread__get(thread);

        if (thread__pid(thread) == -1)
                return NULL;

        return machine__find_thread(machine, thread__pid(thread), thread__pid(thread));
}

int thread__memcpy(struct thread *thread, struct machine *machine,
                   void *buf, u64 ip, int len, bool *is64bit)
{
        u8 cpumode = PERF_RECORD_MISC_USER;
        struct addr_location al;
        struct dso *dso;
        long offset;

        if (machine__kernel_ip(machine, ip))
                cpumode = PERF_RECORD_MISC_KERNEL;

        addr_location__init(&al);
        if (!thread__find_map(thread, cpumode, ip, &al)) {
                addr_location__exit(&al);
                return -1;
        }

        dso = map__dso(al.map);

        if (!dso || dso__data(dso)->status == DSO_DATA_STATUS_ERROR || map__load(al.map) < 0) {
                addr_location__exit(&al);
                return -1;
        }

        offset = map__map_ip(al.map, ip);
        if (is64bit)
                *is64bit = dso__is_64_bit(dso);

        addr_location__exit(&al);

        return dso__data_read_offset(dso, machine, offset, buf, len);
}

void thread__free_stitch_list(struct thread *thread)
{
        struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread);
        struct stitch_list *pos, *tmp;

        if (!lbr_stitch)
                return;

        list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
                map_symbol__exit(&pos->cursor.ms);
                list_del_init(&pos->node);
                free(pos);
        }

        list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) {
                list_del_init(&pos->node);
                free(pos);
        }

        for (unsigned int i = 0 ; i < lbr_stitch->prev_lbr_cursor_size; i++)
                map_symbol__exit(&lbr_stitch->prev_lbr_cursor[i].ms);

        zfree(&lbr_stitch->prev_lbr_cursor);
        free(thread__lbr_stitch(thread));
        thread__set_lbr_stitch(thread, NULL);
}