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// SPDX-License-Identifier: GPL-2.0
#include "comm.h"
#include "util.h"
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/refcount.h>
#include <linux/rbtree.h>
#include "rwsem.h"
struct comm_str {
char *str;
struct rb_node rb_node;
refcount_t refcnt;
};
/* Should perhaps be moved to struct machine */
static struct rb_root comm_str_root;
static struct rw_semaphore comm_str_lock = {.lock = PTHREAD_RWLOCK_INITIALIZER,};
static struct comm_str *comm_str__get(struct comm_str *cs)
{
if (cs && refcount_inc_not_zero(&cs->refcnt))
return cs;
return NULL;
}
static void comm_str__put(struct comm_str *cs)
{
if (cs && refcount_dec_and_test(&cs->refcnt)) {
down_write(&comm_str_lock);
rb_erase(&cs->rb_node, &comm_str_root);
up_write(&comm_str_lock);
zfree(&cs->str);
free(cs);
}
}
static struct comm_str *comm_str__alloc(const char *str)
{
struct comm_str *cs;
cs = zalloc(sizeof(*cs));
if (!cs)
return NULL;
cs->str = strdup(str);
if (!cs->str) {
free(cs);
return NULL;
}
refcount_set(&cs->refcnt, 1);
return cs;
}
static
struct comm_str *__comm_str__findnew(const char *str, struct rb_root *root)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct comm_str *iter, *new;
int cmp;
while (*p != NULL) {
parent = *p;
iter = rb_entry(parent, struct comm_str, rb_node);
/*
* If we race with comm_str__put, iter->refcnt is 0
* and it will be removed within comm_str__put call
* shortly, ignore it in this search.
*/
cmp = strcmp(str, iter->str);
if (!cmp && comm_str__get(iter))
return iter;
if (cmp < 0)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
}
new = comm_str__alloc(str);
if (!new)
return NULL;
rb_link_node(&new->rb_node, parent, p);
rb_insert_color(&new->rb_node, root);
return new;
}
static struct comm_str *comm_str__findnew(const char *str, struct rb_root *root)
{
struct comm_str *cs;
down_write(&comm_str_lock);
cs = __comm_str__findnew(str, root);
up_write(&comm_str_lock);
return cs;
}
struct comm *comm__new(const char *str, u64 timestamp, bool exec)
{
struct comm *comm = zalloc(sizeof(*comm));
if (!comm)
return NULL;
comm->start = timestamp;
comm->exec = exec;
comm->comm_str = comm_str__findnew(str, &comm_str_root);
if (!comm->comm_str) {
free(comm);
return NULL;
}
return comm;
}
int comm__override(struct comm *comm, const char *str, u64 timestamp, bool exec)
{
struct comm_str *new, *old = comm->comm_str;
new = comm_str__findnew(str, &comm_str_root);
if (!new)
return -ENOMEM;
comm_str__put(old);
comm->comm_str = new;
comm->start = timestamp;
if (exec)
comm->exec = true;
return 0;
}
void comm__free(struct comm *comm)
{
comm_str__put(comm->comm_str);
free(comm);
}
const char *comm__str(const struct comm *comm)
{
return comm->comm_str->str;
}
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