Code drop from //branches/cupcake/...@124589

1 files changed, 166 insertions, 0 deletions

diff --git a/hardware.c b/hardware.c
new file mode 100644
index 0000000..bff4215
--- /dev/null
+++ b/hardware.c
@@ -0,0 +1,166 @@
+/*
+ * 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
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <hardware/hardware.h>
+
+#include <cutils/properties.h>
+
+#include <dlfcn.h>
+#include <string.h>
+#include <pthread.h>
+#include <errno.h>
+#include <limits.h>
+
+#define LOG_TAG "HAL"
+#include <utils/Log.h>
+
+/** Base path of the hal modules */
+#define HAL_LIBRARY_PATH "/system/lib/hw"
+
+/**
+ * There are a set of variant filename
+ * for modules. The form of the filename
+ * is "<MODULE_ID>.variant.so" so for the
+ * led module the Dream variants of base are
+ * "ro.product.board" and "ro.arch" would be:
+ *
+ * led.trout.so
+ * led.ARMV6.so
+ * led.default.so
+ */
+#define HAL_DEFAULT_VARIANT "default"
+#define HAL_VARIANT_KEYS_COUNT 3
+static const char *variant_keys[HAL_VARIANT_KEYS_COUNT] = {
+    "ro.product.board",
+    "ro.arch",
+    HAL_DEFAULT_VARIANT
+};
+
+/**
+ * Load the file defined by the path and if succesfull
+ * return the dlopen handle and the hmi.
+ * @return 0 = success, !0 = failure.
+ */
+static int load(const char *id,
+                const char *path,
+                void **pHandle,
+                const struct hw_module_t **pHmi)
+{
+    int status;
+    void *handle;
+    const struct hw_module_t *hmi;
+
+    LOGV("load: E id=%s path=%s", id, path);
+
+    /*
+     * 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();
+        LOGE("load: module=%s error=%s", path, err_str);
+        status = -EINVAL;
+        goto done;
+    }
+
+    /* Get the address of the struct hal_module_info. */
+    const char *sym = HAL_MODULE_INFO_SYM_AS_STR;
+    hmi = (const struct hw_module_t *)dlsym(handle, sym);
+    if (hmi == NULL) {
+        char const *err_str = dlerror();
+        LOGE("load: couldn't find symbol %s", sym);
+        status = -EINVAL;
+        goto done;
+    }
+
+    /* Check that the id matches */
+    if (strcmp(id, hmi->id) != 0) {
+        LOGE("load: id=%s != hmi->id=%s", id, hmi->id);
+        status = -EINVAL;
+        goto done;
+    }
+
+    /* success */
+    status = 0;
+
+done:
+    if (status != 0) {
+        hmi = NULL;
+        if (handle != NULL) {
+            dlclose(handle);
+            handle = NULL;
+        }
+    }
+
+    *pHmi = hmi;
+    *pHandle = handle;
+
+    LOGV("load: X id=%s path=%s hmi=%p pHandle=%p status=%d",
+         id, path, *pHmi, *pHandle, status);
+    return status;
+}
+
+int hw_get_module(const char *id, const struct hw_module_t **module) 
+{
+    int status;
+    const struct hw_module_t *hmi = NULL;
+    char path[PATH_MAX];
+    char variant[PATH_MAX];
+    void *handle = NULL;
+    int i;
+
+    /*
+     * 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.
+     */
+    
+    LOGV("hal_module_info_get: Load module id=%s", id);
+
+    /* Loop through the configuration variants looking for a module */
+    status = -EINVAL;
+    for (i = 0; (status != 0) && (i < HAL_VARIANT_KEYS_COUNT); i++) {
+
+        /* Get variant or default */
+        if (strcmp(variant_keys[i], HAL_DEFAULT_VARIANT) == 0) {
+            strncpy(variant, HAL_DEFAULT_VARIANT, sizeof(variant)-1);
+            variant[sizeof(variant)-1] = 0;
+        } else {
+            if (property_get(variant_keys[i], variant, NULL) == 0) {
+                continue;
+            }
+        }
+
+        /* Construct the path then try to load */
+        snprintf(path, sizeof(path), "%s/%s.%s.so",
+                HAL_LIBRARY_PATH, id, variant);
+        status = load(id, path, &handle, &hmi);
+    }
+    if (status != 0) {
+        hmi = NULL;
+        if (handle != NULL) {
+            dlclose(handle);
+        }
+    }
+    
+    *module = hmi;
+    LOGV("hal_module_info_get: X id=%s hmi=%p status=%d", id, hmi, status);
+
+    return status;
+}