text: /*
   * Copyright (C) 2007-2016 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 <errno.h>
  #include <stdatomic.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sys/time.h>
  #ifdef __BIONIC__
  #include <android/set_abort_message.h>
  #endif
  
  #include <log/event_tag_map.h>
  #include <log/logd.h>
  #include <log/logger.h>
  #include <log/log_read.h>
  #include <private/android_filesystem_config.h>
  #include <private/android_logger.h>
  
  #include "config_write.h"
  #include "log_portability.h"
  #include "logger.h"
  
  #define LOG_BUF_SIZE 1024
  
  static int __write_to_log_init(log_id_t, struct iovec *vec, size_t nr);
  static int (*write_to_log)(log_id_t, struct iovec *vec, size_t nr) = __write_to_log_init;
  
  /*
   * This is used by the C++ code to decide if it should write logs through
   * the C code.  Basically, if /dev/socket/logd is available, we're running in
   * the simulator rather than a desktop tool and want to use the device.
   */
  static enum {
      kLogUninitialized, kLogNotAvailable, kLogAvailable
  } g_log_status = kLogUninitialized;
  
  static int check_log_uid_permissions()
  {
  #undef __BIONIC__
  #if defined(__BIONIC__)
      uid_t uid = __android_log_uid();
  
      /* Matches clientHasLogCredentials() in logd */
      if ((uid != AID_SYSTEM) && (uid != AID_ROOT) && (uid != AID_LOG)) {
          uid = geteuid();
          if ((uid != AID_SYSTEM) && (uid != AID_ROOT) && (uid != AID_LOG)) {
              gid_t gid = getgid();
              if ((gid != AID_SYSTEM) &&
                      (gid != AID_ROOT) &&
                      (gid != AID_LOG)) {
                  gid = getegid();
                  if ((gid != AID_SYSTEM) &&
                          (gid != AID_ROOT) &&
                          (gid != AID_LOG)) {
                      int num_groups;
                      gid_t *groups;
  
                      num_groups = getgroups(0, NULL);
                      if (num_groups <= 0) {
                          return -EPERM;
                      }
                      groups = calloc(num_groups, sizeof(gid_t));
                      if (!groups) {
                          return -ENOMEM;
                      }
                      num_groups = getgroups(num_groups, groups);
                      while (num_groups > 0) {
                          if (groups[num_groups - 1] == AID_LOG) {
                              break;
                          }
                          --num_groups;
                      }
                      free(groups);
                      if (num_groups <= 0) {
                          return -EPERM;
                      }
                  }
              }
          }
      }
  #endif
      return 0;
  }
  
  static void __android_log_cache_available(
          struct android_log_transport_write *node)
  {
      size_t i;
  
      if (node->logMask) {
          return;
      }
  
      for (i = LOG_ID_MIN; i < LOG_ID_MAX; ++i) {
          if (node->write &&
                  (i != LOG_ID_KERNEL) &&
                  ((i != LOG_ID_SECURITY) ||
                      (check_log_uid_permissions() == 0)) &&
                  (!node->available || ((*node->available)(i) >= 0))) {
              node->logMask |= 1 << i;
          }
      }
  }
  
  LIBLOG_ABI_PUBLIC int __android_log_dev_available()
  {
      struct android_log_transport_write *node;
  
      if (list_empty(&__android_log_transport_write)) {
          return kLogUninitialized;
      }
  
      write_transport_for_each(node, &__android_log_transport_write) {
          __android_log_cache_available(node);
          if (node->logMask) {
              return kLogAvailable;
          }
      }
      return kLogNotAvailable;
  }
  
  /* log_init_lock assumed */
  static int __write_to_log_initialize()
  {
      struct android_log_transport_write *transport;
      struct listnode *n;
      int i = 0, ret = 0;
  
      __android_log_config_write();
      write_transport_for_each_safe(transport, n, &__android_log_transport_write) {
          __android_log_cache_available(transport);
          if (!transport->logMask) {
              list_remove(&transport->node);
              continue;
          }
          if (!transport->open || ((*transport->open)() < 0)) {
              if (transport->close) {
                  (*transport->close)();
              }
              list_remove(&transport->node);
              continue;
          }
          ++ret;
      }
      write_transport_for_each_safe(transport, n, &__android_log_persist_write) {
          __android_log_cache_available(transport);
          if (!transport->logMask) {
              list_remove(&transport->node);
              continue;
          }
          if (!transport->open || ((*transport->open)() < 0)) {
              if (transport->close) {
                  (*transport->close)();
              }
              list_remove(&transport->node);
              continue;
          }
          ++i;
      }
      if (!ret && !i) {
          return -ENODEV;
      }
  
      return ret;
  }
  
  /*
   * Extract a 4-byte value from a byte stream. le32toh open coded
   */
  static inline uint32_t get4LE(const uint8_t* src)
  {
      return src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
  }
  
  static int __write_to_log_daemon(log_id_t log_id, struct iovec *vec, size_t nr)
  {
      struct android_log_transport_write *node;
      int ret;
      struct timespec ts;
      size_t len, i;
  
      for (len = i = 0; i < nr; ++i) {
          len += vec[i].iov_len;
      }
      if (!len) {
          return -EINVAL;
      }
  
  #if defined(__BIONIC__)
      if (log_id == LOG_ID_SECURITY) {
          if (vec[0].iov_len < 4) {
              return -EINVAL;
          }
  
          ret = check_log_uid_permissions();
          if (ret < 0) {
              return ret;
          }
          if (!__android_log_security()) {
              /* If only we could reset downstream logd counter */
              return -EPERM;
          }
      } else if (log_id == LOG_ID_EVENTS) {
          static atomic_uintptr_t map;
          const char *tag;
          EventTagMap *m, *f;
  
          if (vec[0].iov_len < 4) {
              return -EINVAL;
          }
  
          tag = NULL;
          f = NULL;
          m = (EventTagMap *)atomic_load(&map);
  
          if (!m) {
              ret = __android_log_trylock();
              m = (EventTagMap *)atomic_load(&map); /* trylock flush cache */
              if (!m) {
                  m = android_openEventTagMap(EVENT_TAG_MAP_FILE);
                  if (ret) { /* trylock failed, use local copy, mark for close */
                      f = m;
                  } else {
                      if (!m) { /* One chance to open map file */
                          m = (EventTagMap *)(uintptr_t)-1LL;
                      }
                      atomic_store(&map, (uintptr_t)m);
                  }
              }
              if (!ret) { /* trylock succeeded, unlock */
                  __android_log_unlock();
              }
          }
          if (m && (m != (EventTagMap *)(uintptr_t)-1LL)) {
              tag = android_lookupEventTag(m, get4LE(vec[0].iov_base));
          }
          ret = __android_log_is_loggable(ANDROID_LOG_INFO,
                                          tag,
                                          ANDROID_LOG_VERBOSE);
          if (f) { /* local copy marked for close */
              android_closeEventTagMap(f);
          }
          if (!ret) {
              return -EPERM;
          }
      } else {
          /* Validate the incoming tag, tag content can not split across iovec */
          char prio = ANDROID_LOG_VERBOSE;
          const char *tag = vec[0].iov_base;
          size_t len = vec[0].iov_len;
          if (!tag) {
              len = 0;
          }
          if (len > 0) {
              prio = *tag;
              if (len > 1) {
                  --len;
                  ++tag;
              } else {
                  len = vec[1].iov_len;
                  tag = ((const char *)vec[1].iov_base);
                  if (!tag) {
                      len = 0;
                  }
              }
          }
          /* tag must be nul terminated */
          if (strnlen(tag, len) >= len) {
              tag = NULL;
          }
  
          if (!__android_log_is_loggable(prio, tag, ANDROID_LOG_VERBOSE)) {
              return -EPERM;
          }
      }
  
      clock_gettime(android_log_clockid(), &ts);
  #else
      /* simulate clock_gettime(CLOCK_REALTIME, &ts); */
      {
          struct timeval tv;
          gettimeofday(&tv, NULL);
          ts.tv_sec = tv.tv_sec;
          ts.tv_nsec = tv.tv_usec * 1000;
      }
  #endif
  
      ret = 0;
      i = 1 << log_id;
      write_transport_for_each(node, &__android_log_transport_write) {
          if (node->logMask & i) {
              ssize_t retval;
              retval = (*node->write)(log_id, &ts, vec, nr);
              if (ret >= 0) {
                  ret = retval;
              }
          }
      }
  
      write_transport_for_each(node, &__android_log_persist_write) {
          if (node->logMask & i) {
              (void)(*node->write)(log_id, &ts, vec, nr);
          }
      }
  
      return ret;
  }
  
  static int __write_to_log_init(log_id_t log_id, struct iovec *vec, size_t nr)
  {
      __android_log_lock();
  
      if (write_to_log == __write_to_log_init) {
          int ret;
  
          ret = __write_to_log_initialize();
          if (ret < 0) {
              __android_log_unlock();
              if (!list_empty(&__android_log_persist_write)) {
                  __write_to_log_daemon(log_id, vec, nr);
              }
              return ret;
          }
  
          write_to_log = __write_to_log_daemon;
      }
  
      __android_log_unlock();
  
      return write_to_log(log_id, vec, nr);
  }
  
  LIBLOG_ABI_PUBLIC int __android_log_write(int prio, const char *tag,
                                            const char *msg)
  {
      return __android_log_buf_write(LOG_ID_MAIN, prio, tag, msg);
  }
  
  LIBLOG_ABI_PUBLIC int __android_log_buf_write(int bufID, int prio,
                                                const char *tag, const char *msg)
  {
      struct iovec vec[3];
      char tmp_tag[32];
  
      if (!tag)
          tag = "";
  
      /* XXX: This needs to go! */
      if ((bufID != LOG_ID_RADIO) &&
           (!strcmp(tag, "HTC_RIL") ||
          !strncmp(tag, "RIL", 3) || /* Any log tag with "RIL" as the prefix */
          !strncmp(tag, "IMS", 3) || /* Any log tag with "IMS" as the prefix */
          !strcmp(tag, "AT") ||
          !strcmp(tag, "GSM") ||
          !strcmp(tag, "STK") ||
          !strcmp(tag, "CDMA") ||
          !strcmp(tag, "PHONE") ||
          !strcmp(tag, "SMS"))) {
              bufID = LOG_ID_RADIO;
              /* Inform third party apps/ril/radio.. to use Rlog or RLOG */
              snprintf(tmp_tag, sizeof(tmp_tag), "use-Rlog/RLOG-%s", tag);
              tag = tmp_tag;
      }
  
  #if __BIONIC__
      if (prio == ANDROID_LOG_FATAL) {
          android_set_abort_message(msg);
      }
  #endif
  
      vec[0].iov_base = (unsigned char *)&prio;
      vec[0].iov_len  = 1;
      vec[1].iov_base = (void *)tag;
      vec[1].iov_len  = strlen(tag) + 1;
      vec[2].iov_base = (void *)msg;
      vec[2].iov_len  = strlen(msg) + 1;
  
      return write_to_log(bufID, vec, 3);
  }
  
  LIBLOG_ABI_PUBLIC int __android_log_vprint(int prio, const char *tag,
                                             const char *fmt, va_list ap)
  {
      char buf[LOG_BUF_SIZE];
  
      vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
  
      return __android_log_write(prio, tag, buf);
  }
  
  LIBLOG_ABI_PUBLIC int __android_log_print(int prio, const char *tag,
                                            const char *fmt, ...)
  {
      va_list ap;
      char buf[LOG_BUF_SIZE];
  
      va_start(ap, fmt);
      vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
      va_end(ap);
  
      return __android_log_write(prio, tag, buf);
  }
  
  LIBLOG_ABI_PUBLIC int __android_log_buf_print(int bufID, int prio,
                                                const char *tag,
                                                const char *fmt, ...)
  {
      va_list ap;
      char buf[LOG_BUF_SIZE];
  
      va_start(ap, fmt);
      vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
      va_end(ap);
  
      return __android_log_buf_write(bufID, prio, tag, buf);
  }
  
  LIBLOG_ABI_PUBLIC void __android_log_assert(const char *cond, const char *tag,
                                              const char *fmt, ...)
  {
      char buf[LOG_BUF_SIZE];
  
      if (fmt) {
          va_list ap;
          va_start(ap, fmt);
          vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
          va_end(ap);
      } else {
          /* Msg not provided, log condition.  N.B. Do not use cond directly as
           * format string as it could contain spurious '%' syntax (e.g.
           * "%d" in "blocks%devs == 0").
           */
          if (cond)
              snprintf(buf, LOG_BUF_SIZE, "Assertion failed: %s", cond);
          else
              strcpy(buf, "Unspecified assertion failed");
      }
  
      __android_log_write(ANDROID_LOG_FATAL, tag, buf);
      abort(); /* abort so we have a chance to debug the situation */
      /* NOTREACHED */
  }
  
  LIBLOG_ABI_PUBLIC int __android_log_bwrite(int32_t tag,
                                             const void *payload, size_t len)
  {
      struct iovec vec[2];
  
      vec[0].iov_base = &tag;
      vec[0].iov_len = sizeof(tag);
      vec[1].iov_base = (void*)payload;
      vec[1].iov_len = len;
  
      return write_to_log(LOG_ID_EVENTS, vec, 2);
  }
  
  LIBLOG_ABI_PUBLIC int __android_log_security_bwrite(int32_t tag,
                                                      const void *payload,
                                                      size_t len)
  {
      struct iovec vec[2];
  
      vec[0].iov_base = &tag;
      vec[0].iov_len = sizeof(tag);
      vec[1].iov_base = (void*)payload;
      vec[1].iov_len = len;
  
      return write_to_log(LOG_ID_SECURITY, vec, 2);
  }
  
  /*
   * Like __android_log_bwrite, but takes the type as well.  Doesn't work
   * for the general case where we're generating lists of stuff, but very
   * handy if we just want to dump an integer into the log.
   */
  LIBLOG_ABI_PUBLIC int __android_log_btwrite(int32_t tag, char type,
                                              const void *payload, size_t len)
  {
      struct iovec vec[3];
  
      vec[0].iov_base = &tag;
      vec[0].iov_len = sizeof(tag);
      vec[1].iov_base = &type;
      vec[1].iov_len = sizeof(type);
      vec[2].iov_base = (void*)payload;
      vec[2].iov_len = len;
  
      return write_to_log(LOG_ID_EVENTS, vec, 3);
  }
  
  /*
   * Like __android_log_bwrite, but used for writing strings to the
   * event log.
   */
  LIBLOG_ABI_PUBLIC int __android_log_bswrite(int32_t tag, const char *payload)
  {
      struct iovec vec[4];
      char type = EVENT_TYPE_STRING;
      uint32_t len = strlen(payload);
  
      vec[0].iov_base = &tag;
      vec[0].iov_len = sizeof(tag);
      vec[1].iov_base = &type;
      vec[1].iov_len = sizeof(type);
      vec[2].iov_base = &len;
      vec[2].iov_len = sizeof(len);
      vec[3].iov_base = (void*)payload;
      vec[3].iov_len = len;
  
      return write_to_log(LOG_ID_EVENTS, vec, 4);
  }
  
  /*
   * Like __android_log_security_bwrite, but used for writing strings to the
   * security log.
   */
  LIBLOG_ABI_PUBLIC int __android_log_security_bswrite(int32_t tag,
                                                       const char *payload)
  {
      struct iovec vec[4];
      char type = EVENT_TYPE_STRING;
      uint32_t len = strlen(payload);
  
      vec[0].iov_base = &tag;
      vec[0].iov_len = sizeof(tag);
      vec[1].iov_base = &type;
      vec[1].iov_len = sizeof(type);
      vec[2].iov_base = &len;
      vec[2].iov_len = sizeof(len);
      vec[3].iov_base = (void*)payload;
      vec[3].iov_len = len;
  
      return write_to_log(LOG_ID_SECURITY, vec, 4);
  }
  