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// SPDX-License-Identifier: GPL-2.0
#include "../perf.h"
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/kernel.h>
#include <linux/zalloc.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_map_groups(struct thread *thread, struct machine *machine)
{
pid_t pid = thread->pid_;
if (pid == thread->tid || pid == -1) {
thread->mg = map_groups__new(machine);
} else {
struct thread *leader = __machine__findnew_thread(machine, pid, pid);
if (leader) {
thread->mg = map_groups__get(leader->mg);
thread__put(leader);
}
}
return thread->mg ? 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;
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->mg) {
map_groups__put(thread->mg);
thread->mg = NULL;
}
down_write(&thread->namespaces_lock);
list_for_each_entry_safe(namespaces, tmp_namespaces,
&thread->namespaces_list, list) {
list_del(&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(&comm->list);
comm__free(comm);
}
up_write(&thread->comm_lock);
unwind__finish_access(thread);
nsinfo__zput(thread->nsinfo);
srccode_state_free(&thread->srccode_state);
exit_rwsem(&thread->namespaces_lock);
exit_rwsem(&thread->comm_lock);
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 namespaces_event *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 namespaces_event *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;
list_for_each_entry(comm, &thread->comm_list, list) {
if (comm->exec)
return comm;
last = comm;
}
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);
}
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
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