text: /*
   * 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>
  
  #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>
  
  #ifdef HAVE_SELINUX
  #include <selinux/selinux.h>
  #include <selinux/label.h>
  #endif
  
  #include "property_service.h"
  #include "init.h"
  #include "util.h"
  #include "log.h"
  
  #include <device_perms.h>
  
  #define PERSISTENT_PROPERTY_DIR  "/data/property"
  
  static int persistent_properties_loaded = 0;
  static int property_area_inited = 0;
  
  static int property_set_fd = -1;
  
  /* White list of permissions for setting property services. */
  #ifndef PROPERTY_PERMS
  struct {
      const char *prefix;
      unsigned int uid;
      unsigned int gid;
  } property_perms[] = {
      { "net.rmnet",        AID_RADIO,    0 },
      { "net.gprs.",        AID_RADIO,    0 },
      { "net.ppp",          AID_RADIO,    0 },
      { "net.qmi",          AID_RADIO,    0 },
      { "net.lte",          AID_RADIO,    0 },
      { "net.cdma",         AID_RADIO,    0 },
      { "ril.",             AID_RADIO,    0 },
      { "gsm.",             AID_RADIO,    0 },
      { "persist.radio",    AID_RADIO,    0 },
      { "net.dns",          AID_RADIO,    0 },
      { "sys.usb.config",   AID_RADIO,    0 },
      { "net.",             AID_SYSTEM,   0 },
      { "dev.",             AID_SYSTEM,   0 },
      { "runtime.",         AID_SYSTEM,   0 },
      { "hw.",              AID_SYSTEM,   0 },
      { "sys.",             AID_SYSTEM,   0 },
      { "service.",         AID_SYSTEM,   0 },
      { "service.",         AID_RADIO,    0 },
      { "wlan.",            AID_SYSTEM,   0 },
      { "bluetooth.",       AID_BLUETOOTH,   0 },
      { "dhcp.",            AID_SYSTEM,   0 },
      { "dhcp.",            AID_DHCP,     0 },
      { "debug.",           AID_SYSTEM,   0 },
      { "debug.",           AID_SHELL,    0 },
      { "log.",             AID_SHELL,    0 },
      { "service.adb.root", AID_SHELL,    0 },
      { "service.adb.tcp.port", AID_SHELL,    0 },
      { "persist.sys.",     AID_SYSTEM,   0 },
      { "persist.service.", AID_SYSTEM,   0 },
      { "persist.service.", AID_RADIO,    0 },
      { "persist.security.", AID_SYSTEM,   0 },
      { "persist.service.bdroid.", AID_BLUETOOTH,   0 },
      { "selinux."         , AID_SYSTEM,   0 },
      { "net.pdp",          AID_RADIO,    AID_RADIO },
      { "service.bootanim.exit", AID_GRAPHICS, 0 },
  #ifdef PROPERTY_PERMS_APPEND
  PROPERTY_PERMS_APPEND
  #endif
      { NULL, 0, 0 }
  };
  /* Avoid extending this array. Check device_perms.h */
  #endif
  
  /*
   * White list of UID that are allowed to start/stop services.
   * Currently there are no user apps that require.
   */
  #ifndef CONTROL_PERMS
  struct {
      const char *service;
      unsigned int uid;
      unsigned int gid;
  } control_perms[] = {
      { "dumpstate",AID_SHELL, AID_LOG },
      { "ril-daemon",AID_RADIO, AID_RADIO },
  #ifdef CONTROL_PERMS_APPEND
  CONTROL_PERMS_APPEND
  #endif
       {NULL, 0, 0 }
  };
  /* Avoid extending this array. Check device_perms.h */
  #endif
  
  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/__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/__properties__", O_RDONLY);
      if (fd < 0)
          return -1;
  
      unlink("/dev/__properties__");
  
      w->data = data;
      w->size = size;
      w->fd = fd;
      return 0;
  
  out:
      close(fd);
      return -1;
  }
  
  /* (8 header words + 372 toc words) = 1520 bytes */
  /* 1536 bytes header and toc + 372 prop_infos @ 128 bytes = 49152 bytes */
  
  #define PA_COUNT_MAX  372
  #define PA_INFO_START 1536
  #define PA_SIZE       49152
  
  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;
      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 int check_mac_perms(const char *name, char *sctx)
  {
  #ifdef HAVE_SELINUX
      if (is_selinux_enabled() <= 0)
          return 1;
  
      char *tctx = NULL;
      const char *class = "property_service";
      const char *perm = "set";
      int result = 0;
  
      if (!sctx)
          goto err;
  
      if (!sehandle_prop)
          goto err;
  
      if (selabel_lookup(sehandle_prop, &tctx, name, 1) != 0)
          goto err;
  
      if (selinux_check_access(sctx, tctx, class, perm, name) == 0)
          result = 1;
  
      freecon(tctx);
   err:
      return result;
  
  #endif
      return 1;
  }
  
  static int check_control_mac_perms(const char *name, char *sctx)
  {
  #ifdef HAVE_SELINUX
  
      /*
       *  Create a name prefix out of ctl.<service name>
       *  The new prefix allows the use of the existing
       *  property service backend labeling while avoiding
       *  mislabels based on true property prefixes.
       */
      char ctl_name[PROP_VALUE_MAX+4];
      int ret = snprintf(ctl_name, sizeof(ctl_name), "ctl.%s", name);
  
      if (ret < 0 || (size_t) ret >= sizeof(ctl_name))
          return 0;
  
      return check_mac_perms(ctl_name, sctx);
  
  #endif
      return 1;
  }
  
  /*
   * 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, unsigned int uid, unsigned int gid, char *sctx) {
  
      int i;
      if (uid == AID_SYSTEM || uid == AID_ROOT)
        return check_control_mac_perms(name, sctx);
  
      /* Search the ACL */
      for (i = 0; control_perms[i].service; i++) {
          if (strcmp(control_perms[i].service, name) == 0) {
              if ((uid && control_perms[i].uid == uid) ||
                  (gid && control_perms[i].gid == gid)) {
                  return check_control_mac_perms(name, sctx);
              }
          }
      }
      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, unsigned int gid, char *sctx)
  {
      int i;
      if(!strncmp(name, "ro.", 3))
          name +=3;
  
      if (uid == 0)
          return check_mac_perms(name, sctx);
  
      for (i = 0; property_perms[i].prefix; i++) {
          if (strncmp(property_perms[i].prefix, name,
                      strlen(property_perms[i].prefix)) == 0) {
              if ((uid && property_perms[i].uid == uid) ||
                  (gid && property_perms[i].gid == gid)) {
  
                  return check_mac_perms(name, sctx);
              }
          }
      }
  
      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_persistent_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, strlen("net.")) == 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, strlen("persist.")) == 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_persistent_property(name, value);
  #ifdef HAVE_SELINUX
      } else if (strcmp("selinux.reload_policy", name) == 0 &&
                 strcmp("1", value) == 0) {
          selinux_reload_policy();
  #endif
      }
      property_changed(name, value);
      return 0;
  }
  
  void handle_property_set_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);
      char * source_ctx = NULL;
  
      if ((s = accept(property_set_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 = TEMP_FAILURE_RETRY(recv(s, &msg, sizeof(msg), 0));
      if(r != sizeof(prop_msg)) {
          ERROR("sys_prop: mis-match msg size recieved: %d expected: %d errno: %d\n",
                r, sizeof(prop_msg), errno);
          close(s);
          return;
      }
  
      switch(msg.cmd) {
      case PROP_MSG_SETPROP:
          msg.name[PROP_NAME_MAX-1] = 0;
          msg.value[PROP_VALUE_MAX-1] = 0;
  
  #ifdef HAVE_SELINUX
          getpeercon(s, &source_ctx);
  #endif
  
          if(memcmp(msg.name,"ctl.",4) == 0) {
              // Keep the old close-socket-early behavior when handling
              // ctl.* properties.
              close(s);
              if (check_control_perms(msg.value, cr.uid, cr.gid, source_ctx)) {
                  handle_control_message((char*) msg.name + 4, (char*) msg.value);
              } else {
                  ERROR("sys_prop: Unable to %s service ctl [%s] uid:%d gid:%d pid:%d\n",
                          msg.name + 4, msg.value, cr.uid, cr.gid, cr.pid);
              }
          } else {
              if (check_perms(msg.name, cr.uid, cr.gid, source_ctx)) {
                  property_set((char*) msg.name, (char*) msg.value);
              } else {
                  ERROR("sys_prop: permission denied uid:%d  name:%s\n",
                        cr.uid, msg.name);
              }
  
              // Note: bionic's property client code assumes that the
              // property server will not close the socket until *AFTER*
              // the property is written to memory.
              close(s);
          }
  #ifdef HAVE_SELINUX
          freecon(source_ctx);
  #endif
  
          break;
  
      default:
          close(s);
          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 (strncmp("persist.", entry->d_name, strlen("persist.")))
                  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();
  }
  
  void property_load_boot_defaults(void)
  {
      load_properties_from_file(PROP_PATH_RAMDISK_DEFAULT);
  }
  
  int properties_inited(void)
  {
      return property_area_inited;
  }
  
  static void load_override_properties() {
  #ifdef ALLOW_LOCAL_PROP_OVERRIDE
      const char *debuggable = property_get("ro.debuggable");
      if (debuggable && (strcmp(debuggable, "1") == 0)) {
          load_properties_from_file(PROP_PATH_LOCAL_OVERRIDE);
      }
  #endif /* ALLOW_LOCAL_PROP_OVERRIDE */
  }
  
  
  /* When booting an encrypted system, /data is not mounted when the
   * property service is started, so any properties stored there are
   * not loaded.  Vold triggers init to load these properties once it
   * has mounted /data.
   */
  void load_persist_props(void)
  {
      load_override_properties();
      /* Read persistent properties after all default values have been loaded. */
      load_persistent_properties();
  }
  
  void start_property_service(void)
  {
      int fd;
  
      load_properties_from_file(PROP_PATH_SYSTEM_BUILD);
      load_properties_from_file(PROP_PATH_SYSTEM_DEFAULT);
      load_override_properties();
      /* 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;
      fcntl(fd, F_SETFD, FD_CLOEXEC);
      fcntl(fd, F_SETFL, O_NONBLOCK);
  
      listen(fd, 8);
      property_set_fd = fd;
  }
  
  int get_property_set_fd()
  {
      return property_set_fd;
  }
  