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-rw-r--r--legacy_property_service.c211
1 files changed, 211 insertions, 0 deletions
diff --git a/legacy_property_service.c b/legacy_property_service.c
new file mode 100644
index 000000000..0dc95ad48
--- /dev/null
+++ b/legacy_property_service.c
@@ -0,0 +1,211 @@
+/*
+ * 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 <cutils/properties.h>
+
+#include "legacy_properties.h"
+
+#include <sys/mman.h>
+#include <sys/atomics.h>
+#include "legacy_property_service.h"
+
+
+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 = (void*) (((char*) pa_workspace.data) + PA_INFO_START);
+
+ pa = 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) pi) - ((unsigned) 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);
+}
+
+void legacy_properties_init()
+{
+ init_property_area();
+ property_list(copy_property_to_legacy, 0);
+}
+