Merge bitcoin#9856: Terminate immediately when allocation fails

d4ee7ba prevector: assert successful allocation (Cory Fields)
c5f008a don't throw std::bad_alloc when out of memory. Instead, terminate immediately (Cory Fields)

Tree-SHA512: 699ce8df5b1775a99c71d3cfc952b45da1c0091e1a4b6adfac52d5be6144c3d98f88ac3af90e5c73fff2f74666a499feb4a34434683ce5979814e869c0aeddc3

Author: laanwj

src/init.cpp

@@ -941,6 +941,19 @@ ServiceFlags nLocalServices = NODE_NETWORK;
 
 }
 
+[[noreturn]] static void new_handler_terminate()
+{
+    // Rather than throwing std::bad-alloc if allocation fails, terminate
+    // immediately to (try to) avoid chain corruption.
+    // Since LogPrintf may itself allocate memory, set the handler directly
+    // to terminate first.
+    std::set_new_handler(std::terminate);
+    LogPrintf("Error: Out of memory. Terminating.\n");
+
+    // The log was successful, terminate now.
+    std::terminate();
+};
+
 bool AppInitBasicSetup()
 {
     // ********************************************************* Step 1: setup
@@ -993,6 +1006,9 @@ bool AppInitBasicSetup()
     // Ignore SIGPIPE, otherwise it will bring the daemon down if the client closes unexpectedly
     signal(SIGPIPE, SIG_IGN);
 #endif
+
+    std::set_new_handler(new_handler_terminate);
+
     return true;
 }
 

src/prevector.h

@@ -5,6 +5,7 @@
 #ifndef _BITCOIN_PREVECTOR_H_
 #define _BITCOIN_PREVECTOR_H_
 
+#include <assert.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
@@ -170,10 +171,15 @@ class prevector {
             }
         } else {
             if (!is_direct()) {
+                /* FIXME: Because malloc/realloc here won't call new_handler if allocation fails, assert
+                    success. These should instead use an allocator or new/delete so that handlers
+                    are called as necessary, but performance would be slightly degraded by doing so. */
                 _union.indirect = static_cast<char*>(realloc(_union.indirect, ((size_t)sizeof(T)) * new_capacity));
+                assert(_union.indirect);
                 _union.capacity = new_capacity;
             } else {
                 char* new_indirect = static_cast<char*>(malloc(((size_t)sizeof(T)) * new_capacity));
+                assert(new_indirect);
                 T* src = direct_ptr(0);
                 T* dst = reinterpret_cast<T*>(new_indirect);
                 memcpy(dst, src, size() * sizeof(T));