1 files changed, 220 insertions, 0 deletions

diff --git a/legacy_property_service.cpp b/legacy_property_service.cpp
new file mode 100644
index 000000000..90a0d47df
--- /dev/null
+++ b/legacy_property_service.cpp
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2007 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 <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <dirent.h>
+#include <limits.h>
+#include <errno.h>
+
+#include "../../bionic/libc/private/bionic_futex.h"
+
+#include <cutils/properties.h>
+
+#include "legacy_properties.h"
+
+#include <sys/mman.h>
+// Not available in 5.0
+//#include <sys/atomics.h>
+#include "legacy_property_service.h"
+
+#ifndef INT32_MAX
+#define INT32_MAX	(2147483647)
+#endif
+
+static int persistent_properties_loaded = 0;
+static int property_area_inited = 0;
+
+static int property_set_fd = -1;
+
+typedef struct {
+    void *data;
+    size_t size;
+    int fd;
+} workspace;
+
+static int init_workspace(workspace *w, size_t size)
+{
+    void *data;
+    int fd;
+
+        /* dev is a tmpfs that we can use to carve a shared workspace
+         * out of, so let's do that...
+         */
+    fd = open("/dev/__legacy_properties__", O_RDWR | O_CREAT, 0600);
+    if (fd < 0)
+        return -1;
+
+    if (ftruncate(fd, size) < 0)
+        goto out;
+
+    data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+    if(data == MAP_FAILED)
+        goto out;
+
+    close(fd);
+
+    fd = open("/dev/__legacy_properties__", O_RDONLY);
+    if (fd < 0)
+        return -1;
+
+    unlink("/dev/__legacy_properties__");
+
+    w->data = data;
+    w->size = size;
+    w->fd = fd;
+    return 0;
+
+out:
+    close(fd);
+    return -1;
+}
+
+/* (8 header words + 247 toc words) = 1020 bytes */
+/* 1024 bytes header and toc + 247 prop_infos @ 128 bytes = 32640 bytes */
+
+#define PA_COUNT_MAX  247
+#define PA_INFO_START 1024
+#define PA_SIZE       32768
+
+static workspace pa_workspace;
+static prop_info *pa_info_array;
+
+prop_area *__legacy_property_area__;
+
+static int init_property_area(void)
+{
+    prop_area *pa;
+
+    if(pa_info_array)
+        return -1;
+
+    if(init_workspace(&pa_workspace, PA_SIZE))
+        return -1;
+
+    fcntl(pa_workspace.fd, F_SETFD, FD_CLOEXEC);
+
+    pa_info_array = (prop_info*) (((char*) pa_workspace.data) + PA_INFO_START);
+
+    pa = (prop_area*)(pa_workspace.data);
+    memset(pa, 0, PA_SIZE);
+    pa->magic = PROP_AREA_MAGIC;
+    pa->version = PROP_AREA_VERSION;
+
+    /* plug into the lib property services */
+    __legacy_property_area__ = pa;
+    property_area_inited = 1;
+    return 0;
+}
+
+static void update_prop_info(prop_info *pi, const char *value, unsigned len)
+{
+    pi->serial = pi->serial | 1;
+    memcpy(pi->value, value, len + 1);
+    pi->serial = (len << 24) | ((pi->serial + 1) & 0xffffff);
+    __futex_wake(&pi->serial, INT32_MAX);
+}
+
+static const prop_info *__legacy_property_find(const char *name)
+{
+    prop_area *pa = __legacy_property_area__;
+    unsigned count = pa->count;
+    unsigned *toc = pa->toc;
+    unsigned len = strlen(name);
+    prop_info *pi;
+
+    while(count--) {
+        unsigned entry = *toc++;
+        if(TOC_NAME_LEN(entry) != len) continue;
+
+        pi = TOC_TO_INFO(pa, entry);
+        if(memcmp(name, pi->name, len)) continue;
+
+        return pi;
+    }
+
+    return 0;
+}
+
+static int legacy_property_set(const char *name, const char *value)
+{
+    prop_area *pa;
+    prop_info *pi;
+
+    int namelen = strlen(name);
+    int valuelen = strlen(value);
+
+    if(namelen >= PROP_NAME_MAX) return -1;
+    if(valuelen >= PROP_VALUE_MAX) return -1;
+    if(namelen < 1) return -1;
+
+    pi = (prop_info*) __legacy_property_find(name);
+
+
+    if(pi != 0) {
+        /* ro.* properties may NEVER be modified once set */
+        if(!strncmp(name, "ro.", 3)) return -1;
+
+        pa = __legacy_property_area__;
+        update_prop_info(pi, value, valuelen);
+        pa->serial++;
+        __futex_wake(&pa->serial, INT32_MAX);
+    } else {
+        pa = __legacy_property_area__;
+        if(pa->count == PA_COUNT_MAX) return -1;
+
+        pi = pa_info_array + pa->count;
+        pi->serial = (valuelen << 24);
+        memcpy(pi->name, name, namelen + 1);
+        memcpy(pi->value, value, valuelen + 1);
+
+        pa->toc[pa->count] =
+            (namelen << 24) | (((unsigned long) pi) - ((unsigned long) pa));
+
+        pa->count++;
+        pa->serial++;
+        __futex_wake(&pa->serial, INT32_MAX);
+    }
+
+    return 0;
+}
+
+void legacy_get_property_workspace(int *fd, int *sz)
+{
+    *fd = pa_workspace.fd;
+    *sz = pa_workspace.size;
+}
+
+static void copy_property_to_legacy(const char *key, const char *value, void *cookie)
+{
+    legacy_property_set(key, value);
+}
+
+int legacy_properties_init()
+{
+    if(init_property_area() != 0)
+        return -1;
+
+    if(property_list(copy_property_to_legacy, 0) != 0)
+        return -1;
+
+    return 0;
+}