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- // SPDX-License-Identifier: GPL-2.0
- #include <errno.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 <api/fs/fs.h>
- int thread__init_maps(struct thread *thread, struct machine *machine)
- {
- pid_t pid = thread->pid_;
- if (pid == thread->tid || pid == -1) {
- thread->maps = maps__new(machine);
- } else {
- struct thread *leader = __machine__findnew_thread(machine, pid, pid);
- if (leader) {
- thread->maps = maps__get(leader->maps);
- thread__put(leader);
- }
- }
- return thread->maps ? 0 : -1;
- }
- struct thread *thread__new(pid_t pid, pid_t tid)
- {
- char *comm_str;
- struct comm *comm;
- struct thread *thread = zalloc(sizeof(*thread));
- if (thread != NULL) {
- thread->pid_ = pid;
- thread->tid = tid;
- thread->ppid = -1;
- thread->cpu = -1;
- thread->lbr_stitch_enable = false;
- INIT_LIST_HEAD(&thread->namespaces_list);
- INIT_LIST_HEAD(&thread->comm_list);
- init_rwsem(&thread->namespaces_lock);
- init_rwsem(&thread->comm_lock);
- comm_str = malloc(32);
- if (!comm_str)
- goto err_thread;
- snprintf(comm_str, 32, ":%d", tid);
- comm = comm__new(comm_str, 0, false);
- free(comm_str);
- if (!comm)
- goto err_thread;
- list_add(&comm->list, &thread->comm_list);
- refcount_set(&thread->refcnt, 1);
- RB_CLEAR_NODE(&thread->rb_node);
- /* Thread holds first ref to nsdata. */
- thread->nsinfo = nsinfo__new(pid);
- srccode_state_init(&thread->srccode_state);
- }
- return thread;
- err_thread:
- free(thread);
- return NULL;
- }
- void thread__delete(struct thread *thread)
- {
- struct namespaces *namespaces, *tmp_namespaces;
- struct comm *comm, *tmp_comm;
- BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));
- thread_stack__free(thread);
- if (thread->maps) {
- maps__put(thread->maps);
- thread->maps = NULL;
- }
- down_write(&thread->namespaces_lock);
- list_for_each_entry_safe(namespaces, tmp_namespaces,
- &thread->namespaces_list, list) {
- list_del_init(&namespaces->list);
- namespaces__free(namespaces);
- }
- up_write(&thread->namespaces_lock);
- down_write(&thread->comm_lock);
- list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {
- list_del_init(&comm->list);
- comm__free(comm);
- }
- up_write(&thread->comm_lock);
- nsinfo__zput(thread->nsinfo);
- srccode_state_free(&thread->srccode_state);
- exit_rwsem(&thread->namespaces_lock);
- exit_rwsem(&thread->comm_lock);
- thread__free_stitch_list(thread);
- free(thread);
- }
- struct thread *thread__get(struct thread *thread)
- {
- if (thread)
- refcount_inc(&thread->refcnt);
- return thread;
- }
- void thread__put(struct thread *thread)
- {
- if (thread && refcount_dec_and_test(&thread->refcnt)) {
- /*
- * Remove it from the dead threads list, as last reference is
- * gone, if it is in a dead threads list.
- *
- * We may not be there anymore if say, the machine where it was
- * stored was already deleted, so we already removed it from
- * the dead threads and some other piece of code still keeps a
- * reference.
- *
- * This is what 'perf sched' does and finally drops it in
- * perf_sched__lat(), where it calls perf_sched__read_events(),
- * that processes the events by creating a session and deleting
- * it, which ends up destroying the list heads for the dead
- * threads, but before it does that it removes all threads from
- * it using list_del_init().
- *
- * So we need to check here if it is in a dead threads list and
- * if so, remove it before finally deleting the thread, to avoid
- * an use after free situation.
- */
- if (!list_empty(&thread->node))
- list_del_init(&thread->node);
- thread__delete(thread);
- }
- }
- static struct namespaces *__thread__namespaces(const struct thread *thread)
- {
- if (list_empty(&thread->namespaces_list))
- return NULL;
- return list_first_entry(&thread->namespaces_list, struct namespaces, list);
- }
- struct namespaces *thread__namespaces(struct thread *thread)
- {
- struct namespaces *ns;
- down_read(&thread->namespaces_lock);
- ns = __thread__namespaces(thread);
- up_read(&thread->namespaces_lock);
- 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);
- 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);
- ret = __thread__set_namespaces(thread, timestamp, event);
- up_write(&thread->namespaces_lock);
- return ret;
- }
- struct comm *thread__comm(const struct thread *thread)
- {
- if (list_empty(&thread->comm_list))
- return NULL;
- return list_first_entry(&thread->comm_list, struct comm, list);
- }
- struct comm *thread__exec_comm(const struct thread *thread)
- {
- struct comm *comm, *last = NULL, *second_last = NULL;
- list_for_each_entry(comm, &thread->comm_list, list) {
- if (comm->exec)
- return comm;
- second_last = last;
- last = comm;
- }
- /*
- * '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->tid)
- return second_last;
- return last;
- }
- static int ____thread__set_comm(struct thread *thread, const char *str,
- u64 timestamp, bool exec)
- {
- struct comm *new, *curr = thread__comm(thread);
- /* Override the default :tid entry */
- if (!thread->comm_set) {
- 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);
- if (exec)
- unwind__flush_access(thread->maps);
- }
- thread->comm_set = true;
- return 0;
- }
- int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
- bool exec)
- {
- int ret;
- down_write(&thread->comm_lock);
- ret = ____thread__set_comm(thread, str, timestamp, exec);
- up_write(&thread->comm_lock);
- 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->tid) >= (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(const struct thread *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);
- str = __thread__comm_str(thread);
- up_read(&thread->comm_lock);
- return str;
- }
- /* CHECKME: it should probably better return the max comm len from its comm list */
- int thread__comm_len(struct thread *thread)
- {
- if (!thread->comm_len) {
- const char *comm = thread__comm_str(thread);
- if (!comm)
- return 0;
- thread->comm_len = strlen(comm);
- }
- return thread->comm_len;
- }
- size_t thread__fprintf(struct thread *thread, FILE *fp)
- {
- return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
- maps__fprintf(thread->maps, fp);
- }
- int thread__insert_map(struct thread *thread, struct map *map)
- {
- int ret;
- ret = unwind__prepare_access(thread->maps, map, NULL);
- if (ret)
- return ret;
- maps__fixup_overlappings(thread->maps, map, stderr);
- maps__insert(thread->maps, map);
- return 0;
- }
- static int __thread__prepare_access(struct thread *thread)
- {
- bool initialized = false;
- int err = 0;
- struct maps *maps = thread->maps;
- struct map *map;
- down_read(&maps->lock);
- maps__for_each_entry(maps, map) {
- err = unwind__prepare_access(thread->maps, map, &initialized);
- if (err || initialized)
- break;
- }
- up_read(&maps->lock);
- return err;
- }
- static int thread__prepare_access(struct thread *thread)
- {
- int err = 0;
- if (dwarf_callchain_users)
- err = __thread__prepare_access(thread);
- return 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_ == parent->pid_)
- return thread__prepare_access(thread);
- if (thread->maps == parent->maps) {
- pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
- thread->pid_, thread->tid, parent->pid_, parent->tid);
- return 0;
- }
- /* But this one is new process, copy maps. */
- return do_maps_clone ? maps__clone(thread, parent->maps) : 0;
- }
- int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
- {
- if (parent->comm_set) {
- 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->ppid = parent->tid;
- return thread__clone_maps(thread, parent, do_maps_clone);
- }
- void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
- 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++) {
- thread__find_symbol(thread, cpumodes[i], addr, al);
- if (al->map)
- break;
- }
- }
- struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
- {
- if (thread->pid_ == thread->tid)
- return thread__get(thread);
- if (thread->pid_ == -1)
- return NULL;
- return machine__find_thread(machine, thread->pid_, thread->pid_);
- }
- 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;
- long offset;
- if (machine__kernel_ip(machine, ip))
- cpumode = PERF_RECORD_MISC_KERNEL;
- if (!thread__find_map(thread, cpumode, ip, &al) || !al.map->dso ||
- al.map->dso->data.status == DSO_DATA_STATUS_ERROR ||
- map__load(al.map) < 0)
- return -1;
- offset = al.map->map_ip(al.map, ip);
- if (is64bit)
- *is64bit = al.map->dso->is_64_bit;
- return dso__data_read_offset(al.map->dso, machine, offset, buf, len);
- }
- void thread__free_stitch_list(struct thread *thread)
- {
- struct lbr_stitch *lbr_stitch = thread->lbr_stitch;
- struct stitch_list *pos, *tmp;
- if (!lbr_stitch)
- return;
- list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
- 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);
- }
- zfree(&lbr_stitch->prev_lbr_cursor);
- zfree(&thread->lbr_stitch);
- }
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