blob: 4bd5eba5d178a65c5c03aa5f1afb959c84c65957 [file] [log] [blame]
* Copyright (C) 2008 The Android Open Source Project
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include <hardware/hardware.h>
#include <dlfcn.h>
#include <string.h>
#include <pthread.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#define LOG_TAG "HAL"
#define LOG_INFO " I"
#define LOG_WARN " W"
#define LOG_ERROR " E"
#define LOG_DEBUG " D"
#define ALOG(pri, tag, fmt, arg...) fprintf(stderr, tag pri": " fmt"\n", ##arg)
#define info(fmt, arg...) ALOG(LOG_INFO, LOG_TAG, fmt, ##arg)
#define warn(fmt, arg...) ALOG(LOG_WARN, LOG_TAG, fmt, ##arg)
#define error(fmt, arg...) ALOG(LOG_ERROR, LOG_TAG, fmt, ##arg)
* Load the file defined by the variant and if successful
* return the dlopen handle and the hmi.
* @return 0 = success, !0 = failure.
static int load(const char *id,
const char *path,
const struct hw_module_t **pHmi)
int status;
void *handle;
struct hw_module_t *hmi;
const char *sym = HAL_MODULE_INFO_SYM_AS_STR;
* load the symbols resolving undefined symbols before
* dlopen returns. Since RTLD_GLOBAL is not or'd in with
* RTLD_NOW the external symbols will not be global
handle = dlopen(path, RTLD_NOW);
if (handle == NULL) {
char const *err_str = dlerror();
error("load: module=%s\n%s", path, err_str?err_str:"unknown");
status = -EINVAL;
goto done;
/* Get the address of the struct hal_module_info. */
hmi = (struct hw_module_t *)dlsym(handle, sym);
if (hmi == NULL) {
error("load: couldn't find symbol %s", sym);
status = -EINVAL;
goto done;
/* Check that the id matches */
if (strcmp(id, hmi->id) != 0) {
error("load: id=%s != hmi->id=%s", id, hmi->id);
status = -EINVAL;
goto done;
hmi->dso = handle;
*pHmi = hmi;
info("loaded HAL id=%s path=%s hmi=%p handle=%p",
id, path, *pHmi, handle);
return 0;
hmi = NULL;
if (handle != NULL) {
handle = NULL;
return status;
int hw_get_module_by_class(const char *class_id, const char *inst,
const struct hw_module_t **module)
char path[PATH_MAX];
char name[PATH_MAX];
if (inst)
snprintf(name, PATH_MAX, "%s.%s", class_id, inst);
snprintf(name, PATH_MAX, "%s", class_id);
* Here we rely on the fact that calling dlopen multiple times on
* the same .so will simply increment a refcount (and not load
* a new copy of the library).
* We also assume that dlopen() is thread-safe.
snprintf(path, sizeof(path), "%s/", PLUGINDIR, name);
return load(class_id, path, module);
int hw_get_module(const char *id, const struct hw_module_t **module)
return hw_get_module_by_class(id, NULL, module);