125 lines
3.3 KiB
C
125 lines
3.3 KiB
C
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/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <hardware/hardware.h>
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#include <dlfcn.h>
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#include <string.h>
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#include <pthread.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdio.h>
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#define LOG_TAG "HAL"
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#define LOG_INFO " I"
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#define LOG_WARN " W"
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#define LOG_ERROR " E"
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#define LOG_DEBUG " D"
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#define ALOG(pri, tag, fmt, arg...) fprintf(stderr, tag pri": " fmt"\n", ##arg)
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#define info(fmt, arg...) ALOG(LOG_INFO, LOG_TAG, fmt, ##arg)
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#define warn(fmt, arg...) ALOG(LOG_WARN, LOG_TAG, fmt, ##arg)
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#define error(fmt, arg...) ALOG(LOG_ERROR, LOG_TAG, fmt, ##arg)
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/**
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* Load the file defined by the variant and if successful
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* return the dlopen handle and the hmi.
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* @return 0 = success, !0 = failure.
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*/
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static int load(const char *id,
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const char *path,
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const struct hw_module_t **pHmi)
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{
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int status;
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void *handle;
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struct hw_module_t *hmi;
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const char *sym = HAL_MODULE_INFO_SYM_AS_STR;
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/*
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* load the symbols resolving undefined symbols before
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* dlopen returns. Since RTLD_GLOBAL is not or'd in with
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* RTLD_NOW the external symbols will not be global
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*/
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handle = dlopen(path, RTLD_NOW);
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if (handle == NULL) {
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char const *err_str = dlerror();
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error("load: module=%s\n%s", path, err_str?err_str:"unknown");
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status = -EINVAL;
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goto done;
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}
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/* Get the address of the struct hal_module_info. */
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hmi = (struct hw_module_t *)dlsym(handle, sym);
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if (hmi == NULL) {
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error("load: couldn't find symbol %s", sym);
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status = -EINVAL;
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goto done;
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}
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/* Check that the id matches */
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if (strcmp(id, hmi->id) != 0) {
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error("load: id=%s != hmi->id=%s", id, hmi->id);
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status = -EINVAL;
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goto done;
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}
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hmi->dso = handle;
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*pHmi = hmi;
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info("loaded HAL id=%s path=%s hmi=%p handle=%p",
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id, path, *pHmi, handle);
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return 0;
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done:
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hmi = NULL;
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if (handle != NULL) {
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dlclose(handle);
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handle = NULL;
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}
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return status;
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}
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int hw_get_module_by_class(const char *class_id, const char *inst,
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const struct hw_module_t **module)
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{
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char path[PATH_MAX];
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char name[PATH_MAX];
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if (inst)
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snprintf(name, PATH_MAX, "%s.%s", class_id, inst);
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else
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snprintf(name, PATH_MAX, "%s", class_id);
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/*
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* Here we rely on the fact that calling dlopen multiple times on
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* the same .so will simply increment a refcount (and not load
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* a new copy of the library).
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* We also assume that dlopen() is thread-safe.
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*/
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snprintf(path, sizeof(path), "%s/%s.default.so", PLUGINDIR, name);
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return load(class_id, path, module);
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}
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int hw_get_module(const char *id, const struct hw_module_t **module)
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{
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return hw_get_module_by_class(id, NULL, module);
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}
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