linux/tools/perf/util/comm.c
Elena Reshetova 6df74bc08b perf comm: Convert comm_str.refcnt from atomic_t to refcount_t
The refcount_t type and corresponding API should be used instead of
atomic_t when the variable is used as a reference counter.

This allows to avoid accidental refcounter overflows that might lead to
use-after-free situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Kook <keescook@chromium.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Kook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: alsa-devel@alsa-project.org
Link: http://lkml.kernel.org/r/1487691303-31858-4-git-send-email-elena.reshetova@intel.com
[ Reinstated comm_str__get() function, needed when reusing entries in the rbtree ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-03-03 19:07:15 -03:00

128 lines
2.2 KiB
C

#include "comm.h"
#include "util.h"
#include <stdlib.h>
#include <stdio.h>
#include <linux/refcount.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 comm_str *comm_str__get(struct comm_str *cs)
{
if (cs)
refcount_inc(&cs->refcnt);
return cs;
}
static void comm_str__put(struct comm_str *cs)
{
if (cs && refcount_dec_and_test(&cs->refcnt)) {
rb_erase(&cs->rb_node, &comm_str_root);
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);
cmp = strcmp(str, iter->str);
if (!cmp)
return comm_str__get(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;
}
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;
}