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/*
* 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 property_area_inited = 0;
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 __unused)
{
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;
}
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