diff options
Diffstat (limited to 'legacy_property_service.c')
| -rw-r--r-- | legacy_property_service.c | 211 |
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); +} + |