diff --git a/libc/system_properties/prop_area.cpp b/libc/system_properties/prop_area.cpp
new file mode 100644
index 0000000..f6c7fa1
--- /dev/null
+++ b/libc/system_properties/prop_area.cpp
@@ -0,0 +1,373 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/cdefs.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/xattr.h>
+#include <unistd.h>
+
+#include <new>
+
+#include <async_safe/log.h>
+
+#include "prop_area.h"
+#include "system_property_globals.h"
+
+constexpr size_t PA_SIZE = 128 * 1024;
+constexpr uint32_t PROP_AREA_MAGIC = 0x504f5250;
+constexpr uint32_t PROP_AREA_VERSION = 0xfc6ed0ab;
+
+static size_t pa_data_size;
+
+prop_area* prop_area::map_prop_area_rw(const char* filename, const char* context,
+                                       bool* fsetxattr_failed) {
+  /* dev is a tmpfs that we can use to carve a shared workspace
+   * out of, so let's do that...
+   */
+  const int fd = open(filename, O_RDWR | O_CREAT | O_NOFOLLOW | O_CLOEXEC | O_EXCL, 0444);
+
+  if (fd < 0) {
+    if (errno == EACCES) {
+      /* for consistency with the case where the process has already
+       * mapped the page in and segfaults when trying to write to it
+       */
+      abort();
+    }
+    return nullptr;
+  }
+
+  if (context) {
+    if (fsetxattr(fd, XATTR_NAME_SELINUX, context, strlen(context) + 1, 0) != 0) {
+      async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+                            "fsetxattr failed to set context (%s) for \"%s\"", context, filename);
+      /*
+       * fsetxattr() will fail during system properties tests due to selinux policy.
+       * We do not want to create a custom policy for the tester, so we will continue in
+       * this function but set a flag that an error has occurred.
+       * Init, which is the only daemon that should ever call this function will abort
+       * when this error occurs.
+       * Otherwise, the tester will ignore it and continue, albeit without any selinux
+       * property separation.
+       */
+      if (fsetxattr_failed) {
+        *fsetxattr_failed = true;
+      }
+    }
+  }
+
+  if (ftruncate(fd, PA_SIZE) < 0) {
+    close(fd);
+    return nullptr;
+  }
+
+  pa_size = PA_SIZE;
+  pa_data_size = pa_size - sizeof(prop_area);
+
+  void* const memory_area = mmap(nullptr, pa_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+  if (memory_area == MAP_FAILED) {
+    close(fd);
+    return nullptr;
+  }
+
+  prop_area* pa = new (memory_area) prop_area(PROP_AREA_MAGIC, PROP_AREA_VERSION);
+
+  close(fd);
+  return pa;
+}
+
+prop_area* prop_area::map_fd_ro(const int fd) {
+  struct stat fd_stat;
+  if (fstat(fd, &fd_stat) < 0) {
+    return nullptr;
+  }
+
+  if ((fd_stat.st_uid != 0) || (fd_stat.st_gid != 0) ||
+      ((fd_stat.st_mode & (S_IWGRP | S_IWOTH)) != 0) ||
+      (fd_stat.st_size < static_cast<off_t>(sizeof(prop_area)))) {
+    return nullptr;
+  }
+
+  pa_size = fd_stat.st_size;
+  pa_data_size = pa_size - sizeof(prop_area);
+
+  void* const map_result = mmap(nullptr, pa_size, PROT_READ, MAP_SHARED, fd, 0);
+  if (map_result == MAP_FAILED) {
+    return nullptr;
+  }
+
+  prop_area* pa = reinterpret_cast<prop_area*>(map_result);
+  if ((pa->magic() != PROP_AREA_MAGIC) || (pa->version() != PROP_AREA_VERSION)) {
+    munmap(pa, pa_size);
+    return nullptr;
+  }
+
+  return pa;
+}
+
+prop_area* prop_area::map_prop_area(const char* filename) {
+  int fd = open(filename, O_CLOEXEC | O_NOFOLLOW | O_RDONLY);
+  if (fd == -1) return nullptr;
+
+  prop_area* map_result = map_fd_ro(fd);
+  close(fd);
+
+  return map_result;
+}
+
+void* prop_area::allocate_obj(const size_t size, uint_least32_t* const off) {
+  const size_t aligned = __BIONIC_ALIGN(size, sizeof(uint_least32_t));
+  if (bytes_used_ + aligned > pa_data_size) {
+    return nullptr;
+  }
+
+  *off = bytes_used_;
+  bytes_used_ += aligned;
+  return data_ + *off;
+}
+
+prop_bt* prop_area::new_prop_bt(const char* name, uint32_t namelen, uint_least32_t* const off) {
+  uint_least32_t new_offset;
+  void* const p = allocate_obj(sizeof(prop_bt) + namelen + 1, &new_offset);
+  if (p != nullptr) {
+    prop_bt* bt = new (p) prop_bt(name, namelen);
+    *off = new_offset;
+    return bt;
+  }
+
+  return nullptr;
+}
+
+prop_info* prop_area::new_prop_info(const char* name, uint32_t namelen, const char* value,
+                                    uint32_t valuelen, uint_least32_t* const off) {
+  uint_least32_t new_offset;
+  void* const p = allocate_obj(sizeof(prop_info) + namelen + 1, &new_offset);
+  if (p == nullptr) return nullptr;
+
+  prop_info* info;
+  if (valuelen >= PROP_VALUE_MAX) {
+    uint32_t long_value_offset = 0;
+    char* long_location = reinterpret_cast<char*>(allocate_obj(valuelen + 1, &long_value_offset));
+    if (!long_location) return nullptr;
+
+    memcpy(long_location, value, valuelen);
+    long_location[valuelen] = '\0';
+
+    // Both new_offset and long_value_offset are offsets based off of data_, however prop_info
+    // does not know what data_ is, so we change this offset to be an offset from the prop_info
+    // pointer that contains it.
+    long_value_offset -= new_offset;
+
+    info = new (p) prop_info(name, namelen, long_value_offset);
+  } else {
+    info = new (p) prop_info(name, namelen, value, valuelen);
+  }
+  *off = new_offset;
+  return info;
+}
+
+void* prop_area::to_prop_obj(uint_least32_t off) {
+  if (off > pa_data_size) return nullptr;
+
+  return (data_ + off);
+}
+
+inline prop_bt* prop_area::to_prop_bt(atomic_uint_least32_t* off_p) {
+  uint_least32_t off = atomic_load_explicit(off_p, memory_order_consume);
+  return reinterpret_cast<prop_bt*>(to_prop_obj(off));
+}
+
+inline prop_info* prop_area::to_prop_info(atomic_uint_least32_t* off_p) {
+  uint_least32_t off = atomic_load_explicit(off_p, memory_order_consume);
+  return reinterpret_cast<prop_info*>(to_prop_obj(off));
+}
+
+inline prop_bt* prop_area::root_node() {
+  return reinterpret_cast<prop_bt*>(to_prop_obj(0));
+}
+
+static int cmp_prop_name(const char* one, uint32_t one_len, const char* two, uint32_t two_len) {
+  if (one_len < two_len)
+    return -1;
+  else if (one_len > two_len)
+    return 1;
+  else
+    return strncmp(one, two, one_len);
+}
+
+prop_bt* prop_area::find_prop_bt(prop_bt* const bt, const char* name, uint32_t namelen,
+                                 bool alloc_if_needed) {
+  prop_bt* current = bt;
+  while (true) {
+    if (!current) {
+      return nullptr;
+    }
+
+    const int ret = cmp_prop_name(name, namelen, current->name, current->namelen);
+    if (ret == 0) {
+      return current;
+    }
+
+    if (ret < 0) {
+      uint_least32_t left_offset = atomic_load_explicit(&current->left, memory_order_relaxed);
+      if (left_offset != 0) {
+        current = to_prop_bt(&current->left);
+      } else {
+        if (!alloc_if_needed) {
+          return nullptr;
+        }
+
+        uint_least32_t new_offset;
+        prop_bt* new_bt = new_prop_bt(name, namelen, &new_offset);
+        if (new_bt) {
+          atomic_store_explicit(&current->left, new_offset, memory_order_release);
+        }
+        return new_bt;
+      }
+    } else {
+      uint_least32_t right_offset = atomic_load_explicit(&current->right, memory_order_relaxed);
+      if (right_offset != 0) {
+        current = to_prop_bt(&current->right);
+      } else {
+        if (!alloc_if_needed) {
+          return nullptr;
+        }
+
+        uint_least32_t new_offset;
+        prop_bt* new_bt = new_prop_bt(name, namelen, &new_offset);
+        if (new_bt) {
+          atomic_store_explicit(&current->right, new_offset, memory_order_release);
+        }
+        return new_bt;
+      }
+    }
+  }
+}
+
+const prop_info* prop_area::find_property(prop_bt* const trie, const char* name, uint32_t namelen,
+                                          const char* value, uint32_t valuelen,
+                                          bool alloc_if_needed) {
+  if (!trie) return nullptr;
+
+  const char* remaining_name = name;
+  prop_bt* current = trie;
+  while (true) {
+    const char* sep = strchr(remaining_name, '.');
+    const bool want_subtree = (sep != nullptr);
+    const uint32_t substr_size = (want_subtree) ? sep - remaining_name : strlen(remaining_name);
+
+    if (!substr_size) {
+      return nullptr;
+    }
+
+    prop_bt* root = nullptr;
+    uint_least32_t children_offset = atomic_load_explicit(&current->children, memory_order_relaxed);
+    if (children_offset != 0) {
+      root = to_prop_bt(&current->children);
+    } else if (alloc_if_needed) {
+      uint_least32_t new_offset;
+      root = new_prop_bt(remaining_name, substr_size, &new_offset);
+      if (root) {
+        atomic_store_explicit(&current->children, new_offset, memory_order_release);
+      }
+    }
+
+    if (!root) {
+      return nullptr;
+    }
+
+    current = find_prop_bt(root, remaining_name, substr_size, alloc_if_needed);
+    if (!current) {
+      return nullptr;
+    }
+
+    if (!want_subtree) break;
+
+    remaining_name = sep + 1;
+  }
+
+  uint_least32_t prop_offset = atomic_load_explicit(&current->prop, memory_order_relaxed);
+  if (prop_offset != 0) {
+    return to_prop_info(&current->prop);
+  } else if (alloc_if_needed) {
+    uint_least32_t new_offset;
+    prop_info* new_info = new_prop_info(name, namelen, value, valuelen, &new_offset);
+    if (new_info) {
+      atomic_store_explicit(&current->prop, new_offset, memory_order_release);
+    }
+
+    return new_info;
+  } else {
+    return nullptr;
+  }
+}
+
+bool prop_area::foreach_property(prop_bt* const trie,
+                                 void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
+  if (!trie) return false;
+
+  uint_least32_t left_offset = atomic_load_explicit(&trie->left, memory_order_relaxed);
+  if (left_offset != 0) {
+    const int err = foreach_property(to_prop_bt(&trie->left), propfn, cookie);
+    if (err < 0) return false;
+  }
+  uint_least32_t prop_offset = atomic_load_explicit(&trie->prop, memory_order_relaxed);
+  if (prop_offset != 0) {
+    prop_info* info = to_prop_info(&trie->prop);
+    if (!info) return false;
+    propfn(info, cookie);
+  }
+  uint_least32_t children_offset = atomic_load_explicit(&trie->children, memory_order_relaxed);
+  if (children_offset != 0) {
+    const int err = foreach_property(to_prop_bt(&trie->children), propfn, cookie);
+    if (err < 0) return false;
+  }
+  uint_least32_t right_offset = atomic_load_explicit(&trie->right, memory_order_relaxed);
+  if (right_offset != 0) {
+    const int err = foreach_property(to_prop_bt(&trie->right), propfn, cookie);
+    if (err < 0) return false;
+  }
+
+  return true;
+}
+
+const prop_info* prop_area::find(const char* name) {
+  return find_property(root_node(), name, strlen(name), nullptr, 0, false);
+}
+
+bool prop_area::add(const char* name, unsigned int namelen, const char* value,
+                    unsigned int valuelen) {
+  return find_property(root_node(), name, namelen, value, valuelen, true);
+}
+
+bool prop_area::foreach (void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
+  return foreach_property(root_node(), propfn, cookie);
+}