initial import of Monero base code

contrib/epee/src/mlocker.cpp

@@ -0,0 +1,203 @@
+// Copyright (c) 2018-2023, The Monero 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:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. 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.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// 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 HOLDER 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.
+
+#if defined __GNUC__ && !defined _WIN32
+#define HAVE_MLOCK 1
+#endif
+
+#include <unistd.h>
+#if defined HAVE_MLOCK
+#include <sys/mman.h>
+#endif
+#include "misc_log_ex.h"
+#include "syncobj.h"
+#include "mlocker.h"
+
+#include <atomic>
+
+#undef MONERO_DEFAULT_LOG_CATEGORY
+#define MONERO_DEFAULT_LOG_CATEGORY "mlocker"
+
+// did an mlock operation previously fail? we only
+// want to log an error once and be done with it
+static std::atomic<bool> previously_failed{ false };
+
+static size_t query_page_size()
+{
+#if defined HAVE_MLOCK
+  long ret = sysconf(_SC_PAGESIZE);
+  if (ret <= 0)
+  {
+    MERROR("Failed to determine page size");
+    return 0;
+  }
+  return ret;
+#else
+#warning Missing query_page_size implementation
+#endif
+  return 0;
+}
+
+static void do_lock(void *ptr, size_t len)
+{
+#if defined HAVE_MLOCK
+  int ret = mlock(ptr, len);
+  if (ret < 0 && !previously_failed.exchange(true))
+    MERROR("Error locking page at " << ptr << ": " << strerror(errno) << ", subsequent mlock errors will be silenced");
+#else
+#warning Missing do_lock implementation
+#endif
+}
+
+static void do_unlock(void *ptr, size_t len)
+{
+#if defined HAVE_MLOCK
+  int ret = munlock(ptr, len);
+  // check whether we previously failed, but don't set it, this is just
+  // to pacify the errors of mlock()ing failed, in which case unlocking
+  // is also not going to work of course
+  if (ret < 0 && !previously_failed.load())
+    MERROR("Error unlocking page at " << ptr << ": " << strerror(errno));
+#else
+#warning Missing implementation of page size detection
+#endif
+}
+
+namespace epee
+{
+  size_t mlocker::page_size = 0;
+  size_t mlocker::num_locked_objects = 0;
+
+  boost::mutex &mlocker::mutex()
+  {
+    static boost::mutex *vmutex = new boost::mutex();
+    return *vmutex;
+  }
+  std::map<size_t, unsigned int> &mlocker::map()
+  {
+    static std::map<size_t, unsigned int> *vmap = new std::map<size_t, unsigned int>();
+    return *vmap;
+  }
+
+  size_t mlocker::get_page_size()
+  {
+    CRITICAL_REGION_LOCAL(mutex());
+    if (page_size == 0)
+      page_size = query_page_size();
+    return page_size;
+  }
+
+  mlocker::mlocker(void *ptr, size_t len): ptr(ptr), len(len)
+  {
+    lock(ptr, len);
+  }
+
+  mlocker::~mlocker()
+  {
+    try { unlock(ptr, len); }
+    catch (...) { /* ignore and do not propagate through the dtor */ }
+  }
+
+  void mlocker::lock(void *ptr, size_t len)
+  {
+    TRY_ENTRY();
+
+    size_t page_size = get_page_size();
+    if (page_size == 0)
+      return;
+
+    CRITICAL_REGION_LOCAL(mutex());
+    const size_t first = ((uintptr_t)ptr) / page_size;
+    const size_t last = (((uintptr_t)ptr) + len - 1) / page_size;
+    for (size_t page = first; page <= last; ++page)
+      lock_page(page);
+    ++num_locked_objects;
+
+    CATCH_ENTRY_L1("mlocker::lock", void());
+  }
+
+  void mlocker::unlock(void *ptr, size_t len)
+  {
+    TRY_ENTRY();
+
+    size_t page_size = get_page_size();
+    if (page_size == 0)
+      return;
+    CRITICAL_REGION_LOCAL(mutex());
+    const size_t first = ((uintptr_t)ptr) / page_size;
+    const size_t last = (((uintptr_t)ptr) + len - 1) / page_size;
+    for (size_t page = first; page <= last; ++page)
+      unlock_page(page);
+    --num_locked_objects;
+
+    CATCH_ENTRY_L1("mlocker::lock", void());
+  }
+
+  size_t mlocker::get_num_locked_pages()
+  {
+    CRITICAL_REGION_LOCAL(mutex());
+    return map().size();
+  }
+
+  size_t mlocker::get_num_locked_objects()
+  {
+    CRITICAL_REGION_LOCAL(mutex());
+    return num_locked_objects;
+  }
+
+  void mlocker::lock_page(size_t page)
+  {
+    std::pair<std::map<size_t, unsigned int>::iterator, bool> p = map().insert(std::make_pair(page, 1));
+    if (p.second)
+    {
+      do_lock((void*)(page * page_size), page_size);
+    }
+    else
+    {
+      ++p.first->second;
+    }
+  }
+
+  void mlocker::unlock_page(size_t page)
+  {
+    std::map<size_t, unsigned int>::iterator i = map().find(page);
+    if (i == map().end())
+    {
+      MERROR("Attempt to unlock unlocked page at " << (void*)(page * page_size));
+    }
+    else
+    {
+      if (!--i->second)
+      {
+        map().erase(i);
+        do_unlock((void*)(page * page_size), page_size);
+      }
+    }
+  }
+}