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Diffstat (limited to 'init/property_service.c')
| -rw-r--r-- | init/property_service.c | 502 |
1 files changed, 502 insertions, 0 deletions
diff --git a/init/property_service.c b/init/property_service.c new file mode 100644 index 0000000..7a6416b --- /dev/null +++ b/init/property_service.c @@ -0,0 +1,502 @@ +/* + * 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/misc.h> +#include <cutils/sockets.h> +#include <cutils/ashmem.h> + +#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_ +#include <sys/_system_properties.h> + +#include <sys/socket.h> +#include <sys/un.h> +#include <sys/select.h> +#include <sys/types.h> +#include <netinet/in.h> +#include <sys/mman.h> +#include <sys/atomics.h> +#include <private/android_filesystem_config.h> + +#include "property_service.h" +#include "init.h" + +#define PERSISTENT_PROPERTY_DIR "/data/property" + +static int persistent_properties_loaded = 0; + +/* White list of permissions for setting property services. */ +struct { + const char *prefix; + unsigned int uid; +} property_perms[] = { + { "net.rmnet0.", AID_RADIO }, + { "net.gprs.", AID_RADIO }, + { "ril.", AID_RADIO }, + { "gsm.", AID_RADIO }, + { "net.dns", AID_RADIO }, + { "net.", AID_SYSTEM }, + { "dev.", AID_SYSTEM }, + { "runtime.", AID_SYSTEM }, + { "hw.", AID_SYSTEM }, + { "sys.", AID_SYSTEM }, + { "service.", AID_SYSTEM }, + { "wlan.", AID_SYSTEM }, + { "dhcp.", AID_SYSTEM }, + { "dhcp.", AID_DHCP }, + { "debug.", AID_SHELL }, + { "log.", AID_SHELL }, + { "persist.sys.", AID_SYSTEM }, + { "persist.service.", AID_SYSTEM }, + { NULL, 0 } +}; + +/* + * White list of UID that are allowed to start/stop services. + * Currently there are no user apps that require. + */ +struct { + const char *service; + unsigned int uid; +} control_perms[] = { + {NULL, 0 } +}; + +typedef struct { + void *data; + size_t size; + int fd; +} workspace; + +static int init_workspace(workspace *w, size_t size) +{ + void *data; + int fd; + + fd = ashmem_create_region("system_properties", size); + if(fd < 0) + return -1; + + data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if(data == MAP_FAILED) + goto out; + + /* allow the wolves we share with to do nothing but read */ + ashmem_set_prot_region(fd, PROT_READ); + + 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; + +extern prop_area *__system_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 */ + __system_property_area__ = pa; + + 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 int property_write(prop_info *pi, const char *value) +{ + int valuelen = strlen(value); + if(valuelen >= PROP_VALUE_MAX) return -1; + update_prop_info(pi, value, valuelen); + return 0; +} + + +/* + * Checks permissions for starting/stoping system services. + * AID_SYSTEM and AID_ROOT are always allowed. + * + * Returns 1 if uid allowed, 0 otherwise. + */ +static int check_control_perms(const char *name, int uid) { + int i; + if (uid == AID_SYSTEM || uid == AID_ROOT) + return 1; + + /* Search the ACL */ + for (i = 0; control_perms[i].service; i++) { + if (strcmp(control_perms[i].service, name) == 0) { + if (control_perms[i].uid == uid) + return 1; + } + } + return 0; +} + +/* + * Checks permissions for setting system properties. + * Returns 1 if uid allowed, 0 otherwise. + */ +static int check_perms(const char *name, unsigned int uid) +{ + int i; + if (uid == 0) + return 1; + + if(!strncmp(name, "ro.", 3)) + name +=3; + + for (i = 0; property_perms[i].prefix; i++) { + int tmp; + if (strncmp(property_perms[i].prefix, name, + strlen(property_perms[i].prefix)) == 0) { + if (property_perms[i].uid == uid) { + return 1; + } + } + } + + return 0; +} + +const char* property_get(const char *name) +{ + prop_info *pi; + + if(strlen(name) >= PROP_NAME_MAX) return 0; + + pi = (prop_info*) __system_property_find(name); + + if(pi != 0) { + return pi->value; + } else { + return 0; + } +} + +static void write_peristent_property(const char *name, const char *value) +{ + const char *tempPath = PERSISTENT_PROPERTY_DIR "/.temp"; + char path[PATH_MAX]; + int fd, length; + + snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, name); + + fd = open(tempPath, O_WRONLY|O_CREAT|O_TRUNC, 0600); + if (fd < 0) { + ERROR("Unable to write persistent property to temp file %s errno: %d\n", tempPath, errno); + return; + } + write(fd, value, strlen(value)); + close(fd); + + if (rename(tempPath, path)) { + unlink(tempPath); + ERROR("Unable to rename persistent property file %s to %s\n", tempPath, path); + } +} + +int 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*) __system_property_find(name); + + if(pi != 0) { + /* ro.* properties may NEVER be modified once set */ + if(!strncmp(name, "ro.", 3)) return -1; + + pa = __system_property_area__; + update_prop_info(pi, value, valuelen); + pa->serial++; + __futex_wake(&pa->serial, INT32_MAX); + } else { + pa = __system_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); + } + /* If name starts with "net." treat as a DNS property. */ + if (strncmp("net.", name, sizeof("net.") - 1) == 0) { + if (strcmp("net.change", name) == 0) { + return 0; + } + /* + * The 'net.change' property is a special property used track when any + * 'net.*' property name is updated. It is _ONLY_ updated here. Its value + * contains the last updated 'net.*' property. + */ + property_set("net.change", name); + } else if (persistent_properties_loaded && + strncmp("persist.", name, sizeof("persist.") - 1) == 0) { + /* + * Don't write properties to disk until after we have read all default properties + * to prevent them from being overwritten by default values. + */ + write_peristent_property(name, value); + } + property_changed(name, value); + return 0; +} + +static int property_list(void (*propfn)(const char *key, const char *value, void *cookie), + void *cookie) +{ + char name[PROP_NAME_MAX]; + char value[PROP_VALUE_MAX]; + const prop_info *pi; + unsigned n; + + for(n = 0; (pi = __system_property_find_nth(n)); n++) { + __system_property_read(pi, name, value); + propfn(name, value, cookie); + } + return 0; +} + +void handle_property_set_fd(int fd) +{ + prop_msg msg; + int s; + int r; + int res; + struct ucred cr; + struct sockaddr_un addr; + socklen_t addr_size = sizeof(addr); + socklen_t cr_size = sizeof(cr); + + if ((s = accept(fd, (struct sockaddr *) &addr, &addr_size)) < 0) { + return; + } + + /* Check socket options here */ + if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) { + close(s); + ERROR("Unable to recieve socket options\n"); + return; + } + + r = recv(s, &msg, sizeof(msg), 0); + close(s); + if(r != sizeof(prop_msg)) { + ERROR("sys_prop: mis-match msg size recieved: %d expected: %d\n", + r, sizeof(prop_msg)); + return; + } + + switch(msg.cmd) { + case PROP_MSG_SETPROP: + msg.name[PROP_NAME_MAX-1] = 0; + msg.value[PROP_VALUE_MAX-1] = 0; + + if(memcmp(msg.name,"ctl.",4) == 0) { + if (check_control_perms(msg.value, cr.uid)) { + handle_control_message((char*) msg.name + 4, (char*) msg.value); + } else { + ERROR("sys_prop: Unable to %s service ctl [%s] uid: %d pid:%d\n", + msg.name + 4, msg.value, cr.uid, cr.pid); + } + } else { + if (check_perms(msg.name, cr.uid)) { + property_set((char*) msg.name, (char*) msg.value); + } else { + ERROR("sys_prop: permission denied uid:%d name:%s\n", + cr.uid, msg.name); + } + } + break; + + default: + break; + } +} + +void get_property_workspace(int *fd, int *sz) +{ + *fd = pa_workspace.fd; + *sz = pa_workspace.size; +} + +static void load_properties(char *data) +{ + char *key, *value, *eol, *sol, *tmp; + + sol = data; + while((eol = strchr(sol, '\n'))) { + key = sol; + *eol++ = 0; + sol = eol; + + value = strchr(key, '='); + if(value == 0) continue; + *value++ = 0; + + while(isspace(*key)) key++; + if(*key == '#') continue; + tmp = value - 2; + while((tmp > key) && isspace(*tmp)) *tmp-- = 0; + + while(isspace(*value)) value++; + tmp = eol - 2; + while((tmp > value) && isspace(*tmp)) *tmp-- = 0; + + property_set(key, value); + } +} + +static void load_properties_from_file(const char *fn) +{ + char *data; + unsigned sz; + + data = read_file(fn, &sz); + + if(data != 0) { + load_properties(data); + free(data); + } +} + +static void load_persistent_properties() +{ + DIR* dir = opendir(PERSISTENT_PROPERTY_DIR); + struct dirent* entry; + char path[PATH_MAX]; + char value[PROP_VALUE_MAX]; + int fd, length; + + if (dir) { + while ((entry = readdir(dir)) != NULL) { + if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, "..") || + strncmp("persist.", entry->d_name, sizeof("persist.") - 1)) + continue; +#if HAVE_DIRENT_D_TYPE + if (entry->d_type != DT_REG) + continue; +#endif + /* open the file and read the property value */ + snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, entry->d_name); + fd = open(path, O_RDONLY); + if (fd >= 0) { + length = read(fd, value, sizeof(value) - 1); + if (length >= 0) { + value[length] = 0; + property_set(entry->d_name, value); + } else { + ERROR("Unable to read persistent property file %s errno: %d\n", path, errno); + } + close(fd); + } else { + ERROR("Unable to open persistent property file %s errno: %d\n", path, errno); + } + } + closedir(dir); + } else { + ERROR("Unable to open persistent property directory %s errno: %d\n", PERSISTENT_PROPERTY_DIR, errno); + } + + persistent_properties_loaded = 1; +} + +void property_init(void) +{ + init_property_area(); + load_properties_from_file(PROP_PATH_RAMDISK_DEFAULT); +} + +int start_property_service(void) +{ + int fd; + + load_properties_from_file(PROP_PATH_SYSTEM_BUILD); + load_properties_from_file(PROP_PATH_SYSTEM_DEFAULT); + load_properties_from_file(PROP_PATH_LOCAL_OVERRIDE); + /* Read persistent properties after all default values have been loaded. */ + load_persistent_properties(); + + fd = create_socket(PROP_SERVICE_NAME, SOCK_STREAM, 0666, 0, 0); + if(fd < 0) return -1; + fcntl(fd, F_SETFD, FD_CLOEXEC); + fcntl(fd, F_SETFL, O_NONBLOCK); + + listen(fd, 8); + return fd; +} |