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general: recoded snd_dlobj_ functions

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- changed logic to get/put blocks
- added mutex locking of the symbol list
- added reference counting (do not free used dl handles)

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela 2010-08-23 17:05:36 +02:00
parent be06ab3ee7
commit 91c9c8f1b8
7 changed files with 153 additions and 123 deletions
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134
src/dlmisc.c
View file

@ -29,6 +29,9 @@
#include "list.h"
#include "local.h"
#ifdef HAVE_LIBPTHREAD
#include <pthread.h>
#endif
#ifndef DOC_HIDDEN
#ifndef PIC
@ -169,69 +172,140 @@ void *snd_dlsym(void *handle, const char *name, const char *version)
/*
* dlobj cache
*
* FIXME: add reference counter and proper locking
*/
#ifndef DOC_HIDDEN
struct dlobj_cache {
const char *lib;
const char *name;
void *obj;
void *dlobj;
void *func;
unsigned int refcnt;
struct list_head list;
};
static LIST_HEAD(pcm_dlobj_list);
#ifdef HAVE_LIBPTHREAD
static pthread_mutex_t snd_dlobj_mutex = PTHREAD_MUTEX_INITIALIZER;
void *snd_dlobj_cache_lookup(const char *name)
static inline void snd_dlobj_lock(void)
{
struct list_head *p;
struct dlobj_cache *c;
list_for_each(p, &pcm_dlobj_list) {
c = list_entry(p, struct dlobj_cache, list);
if (strcmp(c->name, name) == 0)
return c->func;
}
return NULL;
pthread_mutex_lock(&snd_dlobj_mutex);
}
int snd_dlobj_cache_add(const char *name, void *dlobj, void *open_func)
static inline void snd_dlobj_unlock(void)
{
pthread_mutex_unlock(&snd_dlobj_mutex);
}
#else
static inline void snd_dlobj_lock(void) {}
static inline void snd_dlobj_unlock(void) {}
#endif
static LIST_HEAD(pcm_dlobj_list);
void *snd_dlobj_cache_get(const char *lib, const char *name,
const char *version, int verbose)
{
struct list_head *p;
struct dlobj_cache *c;
void *func, *dlobj = NULL;
int dlobj_close = 0;
snd_dlobj_lock();
list_for_each(p, &pcm_dlobj_list) {
c = list_entry(p, struct dlobj_cache, list);
if (strcmp(c->name, name) == 0)
return 0; /* already exists */
if (c->lib && lib && strcmp(c->lib, lib) != 0)
continue;
if (!c->lib && lib)
continue;
if (!lib && c->lib)
continue;
dlobj = c->dlobj;
if (strcmp(c->name, name) == 0) {
c->refcnt++;
func = c->func;
snd_dlobj_unlock();
return func;
}
}
if (dlobj == NULL) {
dlobj = snd_dlopen(lib, RTLD_NOW);
if (dlobj == NULL) {
if (verbose)
SNDERR("Cannot open shared library %s",
lib ? lib : "[builtin]");
snd_dlobj_unlock();
return NULL;
}
dlobj_close = 1;
}
func = snd_dlsym(dlobj, name, version);
if (func == NULL) {
if (verbose)
SNDERR("symbol %s is not defined inside %s",
name, lib ? lib : "[builtin]");
goto __err;
}
c = malloc(sizeof(*c));
if (! c)
return -ENOMEM;
goto __err;
c->refcnt = 1;
c->lib = lib ? strdup(lib) : NULL;
c->name = strdup(name);
if (! c->name) {
if ((lib && ! c->lib) || ! c->name) {
free((void *)c->name);
free((void *)c->lib);
free(c);
return -ENOMEM;
__err:
if (dlobj_close)
snd_dlclose(dlobj);
snd_dlobj_unlock();
return NULL;
}
c->obj = dlobj;
c->func = open_func;
c->dlobj = dlobj;
c->func = func;
list_add_tail(&c->list, &pcm_dlobj_list);
return 0;
snd_dlobj_unlock();
return func;
}
int snd_dlobj_cache_put(void *func)
{
struct list_head *p;
struct dlobj_cache *c;
unsigned int refcnt;
snd_dlobj_lock();
list_for_each(p, &pcm_dlobj_list) {
c = list_entry(p, struct dlobj_cache, list);
if (c->func == func) {
refcnt = c->refcnt;
if (c->refcnt > 0)
c->refcnt--;
snd_dlobj_unlock();
return refcnt == 1 ? 0 : -EINVAL;
}
}
snd_dlobj_unlock();
return -ENOENT;
}
void snd_dlobj_cache_cleanup(void)
{
struct list_head *p;
struct list_head *p, *npos;
struct dlobj_cache *c;
while (! list_empty(&pcm_dlobj_list)) {
p = pcm_dlobj_list.next;
snd_dlobj_lock();
list_for_each_safe(p, npos, &pcm_dlobj_list) {
c = list_entry(p, struct dlobj_cache, list);
list_del(p);
snd_dlclose(c->obj);
free((void *)c->name); /* shut up gcc warning */
free(c);
if (c->refcnt == 0) {
list_del(p);
snd_dlclose(c->dlobj);
free((void *)c->name); /* shut up gcc warning */
free((void *)c->lib); /* shut up gcc warning */
free(c);
}
}
snd_dlobj_unlock();
}
#endif