Add signal guard to map_handle::write()

8 files changed, 123 insertions, 45 deletions

diff --git a/include/afio/revision.hpp b/include/afio/revision.hpp
index 976a7951..f8266792 100644
--- a/include/afio/revision.hpp
+++ b/include/afio/revision.hpp
@@ -1,4 +1,4 @@
 // Note the second line of this file must ALWAYS be the git SHA, third line ALWAYS the git SHA update time
-#define AFIO_PREVIOUS_COMMIT_REF    f976a6f1277af7a84744f789d1a3f69aed345b68
-#define AFIO_PREVIOUS_COMMIT_DATE   "2018-06-08 12:59:43 +00:00"
-#define AFIO_PREVIOUS_COMMIT_UNIQUE f976a6f1
+#define AFIO_PREVIOUS_COMMIT_REF    128ff433151efbad5585de55c3e365a982ba1acb
+#define AFIO_PREVIOUS_COMMIT_DATE   "2018-06-18 20:18:55 +00:00"
+#define AFIO_PREVIOUS_COMMIT_UNIQUE 128ff433
diff --git a/include/afio/v2.0/algorithm/shared_fs_mutex/memory_map.hpp b/include/afio/v2.0/algorithm/shared_fs_mutex/memory_map.hpp
index 321f1bff..b71de0b2 100644
--- a/include/afio/v2.0/algorithm/shared_fs_mutex/memory_map.hpp
+++ b/include/afio/v2.0/algorithm/shared_fs_mutex/memory_map.hpp
@@ -29,7 +29,7 @@ Distributed under the Boost Software License, Version 1.0.
 #include "base.hpp"
 
 #ifdef __has_include
-#if __has_include("../../../quickcpplib/include/algorithm/hash.hpp")
+#if __has_include("../../quickcpplib/include/algorithm/hash.hpp")
 #include "../../quickcpplib/include/algorithm/hash.hpp"
 #include "../../quickcpplib/include/algorithm/small_prng.hpp"
 #include "../../quickcpplib/include/spinlock.hpp"
diff --git a/include/afio/v2.0/config.hpp b/include/afio/v2.0/config.hpp
index d8046bc3..2e8016fc 100644
--- a/include/afio/v2.0/config.hpp
+++ b/include/afio/v2.0/config.hpp
@@ -441,7 +441,7 @@ public:
   ~error_domain() = default;
 
 protected:
-  virtual inline string_ref _message(const SYSTEM_ERROR2_NAMESPACE::status_code<void> &code) const noexcept override final;
+  virtual inline string_ref _do_message(const SYSTEM_ERROR2_NAMESPACE::status_code<void> &code) const noexcept override final;
 };
 #else
 template <class BaseStatusCodeDomain> using error_domain = BaseStatusCodeDomain;
@@ -1045,11 +1045,11 @@ namespace detail
 
 #if AFIO_EXPERIMENTAL_STATUS_CODE
 #ifndef AFIO_DISABLE_PATHS_IN_FAILURE_INFO
-template <class BaseStatusCodeDomain> inline typename error_domain<BaseStatusCodeDomain>::string_ref error_domain<BaseStatusCodeDomain>::_message(const SYSTEM_ERROR2_NAMESPACE::status_code<void> &code) const noexcept  // NOLINT
+template <class BaseStatusCodeDomain> inline typename error_domain<BaseStatusCodeDomain>::string_ref error_domain<BaseStatusCodeDomain>::_do_message(const SYSTEM_ERROR2_NAMESPACE::status_code<void> &code) const noexcept  // NOLINT
 {
   assert(code.domain() == *this);
   const auto &v = static_cast<const SYSTEM_ERROR2_NAMESPACE::status_code<error_domain> &>(code);  // NOLINT
-  std::string ret = _base::_message(code).c_str();
+  std::string ret = _base::_do_message(code).c_str();
   detail::append_path_info(v.value(), ret);
   char *p = (char *) malloc(ret.size() + 1);
   if(p == nullptr)
diff --git a/include/afio/v2.0/detail/impl/posix/map_handle.ipp b/include/afio/v2.0/detail/impl/posix/map_handle.ipp
index 4742b6b1..44860dcf 100644
--- a/include/afio/v2.0/detail/impl/posix/map_handle.ipp
+++ b/include/afio/v2.0/detail/impl/posix/map_handle.ipp
@@ -25,6 +25,8 @@ Distributed under the Boost Software License, Version 1.0.
 #include "../../../map_handle.hpp"
 #include "../../../utils.hpp"
 
+#include "../../../quickcpplib/include/signal_guard.hpp"
+
 #include <sys/mman.h>
 
 AFIO_V2_NAMESPACE_BEGIN
@@ -544,23 +546,67 @@ map_handle::io_result<map_handle::const_buffers_type> map_handle::write(io_reque
   AFIO_LOG_FUNCTION_CALL(this);
   byte *addr = _addr + reqs.offset;
   size_type togo = reqs.offset < _length ? static_cast<size_type>(_length - reqs.offset) : 0;
-  for(const_buffer_type &req : reqs.buffers)
-  {
-    if(togo != 0u)
-    {
-      if(req.len > togo)
-      {
-        req.len = togo;
-      }
-      memcpy(addr, req.data, req.len);
-      req.data = addr;
-      addr += req.len;
-      togo -= req.len;
-    }
-    else
-    {
-      req.len = 0;
-    }
+  if(QUICKCPPLIB_NAMESPACE::signal_guard::signal_guard(QUICKCPPLIB_NAMESPACE::signal_guard::signalc::undefined_memory_access,
+                                                       [&] {
+                                                         for(const_buffer_type &req : reqs.buffers)
+                                                         {
+                                                           if(togo != 0u)
+                                                           {
+                                                             if(req.len > togo)
+                                                             {
+                                                               req.len = togo;
+                                                             }
+                                                             memcpy(addr, req.data, req.len);
+                                                             req.data = addr;
+                                                             addr += req.len;
+                                                             togo -= req.len;
+                                                           }
+                                                           else
+                                                           {
+                                                             req.len = 0;
+                                                           }
+                                                         }
+                                                         return false;
+                                                       },
+                                                       [&](QUICKCPPLIB_NAMESPACE::signal_guard::signalc /* unused */, const void *_info, const void *_context) {
+                                                         assert(signo == QUICKCPPLIB_NAMESPACE::signal_guard::signalc::undefined_memory_access);
+                                                         const auto *info = (const siginfo_t *) _info;
+                                                         assert(info->si_signo == SIGBUS);
+                                                         auto *causingaddr = (byte *) info->si_addr;
+                                                         if(causingaddr < _addr || causingaddr >= (_addr + _length))
+                                                         {
+                                                           // Not caused by this map
+                                                           struct sigaction sa;
+                                                           sigaction(SIGBUS, nullptr, &sa);
+                                                           if(sa.sa_flags & SA_SIGINFO)
+                                                           {
+                                                             sa.sa_sigaction(SIGBUS, (siginfo_t *) info, (void *) _context);
+                                                           }
+                                                           else if(sa.sa_handler != SIG_IGN)
+                                                           {
+                                                             if(sa.sa_handler != SIG_DFL)
+                                                             {
+                                                               sa.sa_handler(SIGBUS);
+                                                             }
+                                                             // Painful ...
+                                                             struct sigaction myformer, def;
+                                                             memset(&def, 0, sizeof(def));
+                                                             def.sa_handler = SIG_DFL;
+                                                             sigaction(SIGBUS, &def, &myformer);
+                                                             sigset_t myformer2;
+                                                             sigset_t def2;
+                                                             sigemptyset(&def2);
+                                                             sigaddset(&def2, SIGBUS);
+                                                             pthread_sigmask(SIG_UNBLOCK, &def2, &myformer2);
+                                                             pthread_kill(pthread_self(), SIGBUS);
+                                                             sigaction(SIGBUS, &myformer, nullptr);
+                                                           }
+                                                           abort();
+                                                         }
+                                                         return true;
+                                                       }))
+  {
+    return errc::no_space_on_device;
   }
   return reqs.buffers;
 }
diff --git a/include/afio/v2.0/detail/impl/windows/map_handle.ipp b/include/afio/v2.0/detail/impl/windows/map_handle.ipp
index 50b0e6d0..1331fb01 100644
--- a/include/afio/v2.0/detail/impl/windows/map_handle.ipp
+++ b/include/afio/v2.0/detail/impl/windows/map_handle.ipp
@@ -27,6 +27,7 @@ Distributed under the Boost Software License, Version 1.0.
 #include "import.hpp"
 
 #include "../../../quickcpplib/include/algorithm/hash.hpp"
+#include "../../../quickcpplib/include/signal_guard.hpp"
 
 
 AFIO_V2_NAMESPACE_BEGIN
@@ -812,23 +813,45 @@ map_handle::io_result<map_handle::const_buffers_type> map_handle::write(io_reque
   AFIO_LOG_FUNCTION_CALL(this);
   byte *addr = _addr + reqs.offset;
   size_type togo = reqs.offset < _length ? static_cast<size_type>(_length - reqs.offset) : 0;
-  for(const_buffer_type &req : reqs.buffers)
-  {
-    if(togo != 0u)
-    {
-      if(req.len > togo)
-      {
-        req.len = togo;
-      }
-      memcpy(addr, req.data, req.len);
-      req.data = addr;
-      addr += req.len;
-      togo -= req.len;
-    }
-    else
-    {
-      req.len = 0;
-    }
+  if(QUICKCPPLIB_NAMESPACE::signal_guard::signal_guard(QUICKCPPLIB_NAMESPACE::signal_guard::signalc::undefined_memory_access,
+                                                       [&] {
+                                                         for(const_buffer_type &req : reqs.buffers)
+                                                         {
+                                                           if(togo != 0u)
+                                                           {
+                                                             if(req.len > togo)
+                                                             {
+                                                               req.len = togo;
+                                                             }
+                                                             memcpy(addr, req.data, req.len);
+                                                             req.data = addr;
+                                                             addr += req.len;
+                                                             togo -= req.len;
+                                                           }
+                                                           else
+                                                           {
+                                                             req.len = 0;
+                                                           }
+                                                         }
+                                                         return false;
+                                                       },
+                                                       [&](QUICKCPPLIB_NAMESPACE::signal_guard::signalc signo, const void *_info, const void * /*unused*/) {
+                                                         assert(signo == QUICKCPPLIB_NAMESPACE::signal_guard::signalc::undefined_memory_access);
+                                                         const auto *info = (const _EXCEPTION_RECORD *) _info;
+                                                         assert(info->ExceptionCode == EXCEPTION_IN_PAGE_ERROR);
+                                                         // info->ExceptionInformation[0] = 0=read 1=write 8=DEP
+                                                         // info->ExceptionInformation[1] = causing address
+                                                         // info->ExceptionInformation[2] = NTSTATUS causing exception
+                                                         auto *causingaddr = (byte *) info->ExceptionInformation[1];
+                                                         if(causingaddr < _addr || causingaddr >= (_addr + _length))
+                                                         {
+                                                           // Not caused by this map
+                                                           RaiseException(info->ExceptionCode, info->ExceptionFlags, info->NumberParameters, info->ExceptionInformation);
+                                                         }
+                                                         return true;
+                                                       }))
+  {
+    return errc::no_space_on_device;
   }
   return reqs.buffers;
 }
diff --git a/include/afio/v2.0/map_handle.hpp b/include/afio/v2.0/map_handle.hpp
index 567c7c5c..8c66450a 100644
--- a/include/afio/v2.0/map_handle.hpp
+++ b/include/afio/v2.0/map_handle.hpp
@@ -504,9 +504,11 @@ public:
 
   /*! \brief Read data from the mapped view.
 
-  \note Because this implementation never copies memory, you can pass in buffers with a null address.
+  \note Because this implementation never copies memory, you can pass in buffers with a null address. As this
+  function never reads any memory, no attempt to trap signal raises can be made, this falls onto the user of
+  this function. See `QUICKCPPLIB_NAMESPACE::signal_guard` for a helper function.
 
-  \return The buffers read, which will never be the buffers input because they will point into the mapped view.
+  \return The buffers read, which will never be the buffers input, because they will point into the mapped view.
   The size of each scatter-gather buffer is updated with the number of bytes of that buffer transferred.
   \param reqs A scatter-gather and offset request.
   \param d Ignored.
@@ -519,12 +521,19 @@ public:
 
   /*! \brief Write data to the mapped view.
 
+  \note This call traps signals and structured exception throws using `QUICKCPPLIB_NAMESPACE::signal_guard`.
+  Instantiating a `QUICKCPPLIB_NAMESPACE::signal_guard_install` somewhere much higher up in the call stack
+  will improve performance enormously. The signal guard may cost less than 100 CPU cycles depending on how
+  you configure it. If you don't want the guard, you can write memory directly using `address()`.
+
   \return The buffers written, which will never be the buffers input because they will point at where the data was copied into the mapped view.
   The size of each scatter-gather buffer is updated with the number of bytes of that buffer transferred.
   \param reqs A scatter-gather and offset request.
   \param d Ignored.
-  \errors None, though the various signals and structured exception throws common to using memory maps may occur.
-  \mallocs None.
+  \errors If during the attempt to write the buffers to the map a `SIGBUS` or `EXCEPTION_IN_PAGE_ERROR` is raised,
+  an error code comparing equal to `errc::no_space_on_device` will be returned. This may not always be the cause
+  of the raised signal, but it is by far the most likely.
+  \mallocs None if a `QUICKCPPLIB_NAMESPACE::signal_guard_install` is already instanced.
   */
   AFIO_MAKE_FREE_FUNCTION
   AFIO_HEADERS_ONLY_VIRTUAL_SPEC io_result<const_buffers_type> write(io_request<const_buffers_type> reqs, deadline d = deadline()) noexcept override;
diff --git a/include/afio/v2.0/outcome b/include/afio/v2.0/outcome
-Subproject 95e0a2210dc9fe22f78117be79550197840c4ab
+Subproject 4eb1466c77a0f8c3573f7cb1cb613b977c9758c
diff --git a/include/afio/v2.0/quickcpplib b/include/afio/v2.0/quickcpplib
-Subproject 4f428d18e58c4edd3f8eaf4da36e3d6b717b11a
+Subproject 20df7f8420f1d8f71fe504b84609a9d9863495c