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Diffstat (limited to 'contrib/epee/src/mlocker.cpp')
| -rw-r--r-- | contrib/epee/src/mlocker.cpp | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/contrib/epee/src/mlocker.cpp b/contrib/epee/src/mlocker.cpp new file mode 100644 index 000000000..5573d591a --- /dev/null +++ b/contrib/epee/src/mlocker.cpp @@ -0,0 +1,182 @@ +// Copyright (c) 2018, 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" + +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; + } + MINFO("Page size: " << ret); + 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) + MERROR("Error locking page at " << ptr << ": " << strerror(errno)); +#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); + if (ret < 0) + 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; + return vmutex; + } + std::map<size_t, unsigned int> &mlocker::map() + { + static std::map<size_t, unsigned int> vmap; + 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() + { + unlock(ptr, len); + } + + void mlocker::lock(void *ptr, size_t len) + { + 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; + } + + void mlocker::unlock(void *ptr, size_t len) + { + 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; + } + + 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); + } + } + } +} |