Vectors plugin: searches memory for vectors

Lists embeded STL vectors and pointers to STL vectors found in the given
memory range.

Linux only, enabled with BUILD_VECTORS cmake option.

plugins/CMakeLists.txt

@@ -108,10 +108,15 @@ if(BUILD_KITTENS)
 endif()
 
 IF(UNIX)
-    OPTION(BUILD_KILL_GAME "Build the kill gmae plugin." OFF)
+    OPTION(BUILD_KILL_GAME "Build the kill game plugin." OFF)
     if(BUILD_KILL_GAME)
         DFHACK_PLUGIN(die die.cpp)
     endif()
+
+    OPTION(BUILD_VECTORS "Build the vectors search plugin." OFF)
+    if(BUILD_VECTORS)
+        DFHACK_PLUGIN(vectors vectors.cpp)
+    endif()
 endif()
 
 DFHACK_PLUGIN(reveal reveal.cpp)

plugins/vectors.cpp

@@ -0,0 +1,228 @@
+// Lists embeded STL vectors and pointers to STL vectors found in the given
+// memory range.
+//
+// Linux only, enabled with BUILD_VECTORS cmake option.
+
+#include <dfhack/Core.h>
+#include <dfhack/Console.h>
+#include <dfhack/Export.h>
+#include <dfhack/PluginManager.h>
+#include <dfhack/Process.h>
+#include <vector>
+#include <string>
+
+#include <stdio.h>
+
+using std::vector;
+using std::string;
+using namespace DFHack;
+
+struct t_vecTriplet
+{
+    uint32_t start;
+    uint32_t end;
+    uint32_t alloc_end;
+};
+
+DFhackCExport command_result df_vectors (Core * c, vector <string> & parameters);
+
+DFhackCExport const char * plugin_name ( void )
+{
+    return "vectors";
+}
+
+DFhackCExport command_result plugin_init ( Core * c, std::vector <PluginCommand> &commands)
+{
+    commands.clear();
+    commands.push_back(PluginCommand("vectors",
+               "Scan memory for vectors.\
+\n                1st param: start of scan\
+\n                2nd param: number of bytes to scan",
+                      df_vectors));
+    return CR_OK;
+}
+
+DFhackCExport command_result plugin_shutdown ( Core * c )
+{
+    return CR_OK;
+}
+
+static bool hexOrDec(string &str, uint32_t &value)
+{
+    if (str.find("0x") == 0 && sscanf(str.c_str(), "%x", &value) == 1)
+        return true;
+    else if (sscanf(str.c_str(), "%u", &value) == 1)
+        return true;
+
+    return false;
+}
+
+static void usage(Console &con)
+{
+    con << "Usage: vectors <start of scan address> <# bytes to scan>"
+        << std::endl;
+}
+
+static bool mightBeVec(vector<t_memrange> &heap_ranges,
+                       t_vecTriplet *vec)
+{
+    if ((vec->start > vec->end) || (vec->end > vec->alloc_end))
+        return false;
+
+    if ((vec->end - vec->start) % 4 != 0)
+        return false;
+
+    for (size_t i = 0; i < heap_ranges.size(); i++)
+    {
+        t_memrange &range = heap_ranges[i];
+
+        if (range.isInRange(vec->start) && range.isInRange(vec->alloc_end))
+            return true;
+    }
+
+    return false;
+}
+
+static bool inAnyRange(vector<t_memrange> &ranges, uint32_t ptr)
+{
+    for (size_t i = 0; i < ranges.size(); i++)
+    {
+        if (ranges[i].isInRange(ptr))
+            return true;
+    }
+
+    return false;
+}
+
+static void printVec(Console &con, const char* msg, t_vecTriplet *vec,
+                     uint32_t start, uint32_t pos)
+{
+    uint32_t length = vec->end - vec->start;
+    uint32_t offset = pos - start;
+
+    con.print("%8s offset %06p, addr %010p, start %010p, length %u\n",
+              msg, offset, pos, vec->start, length);
+}
+
+DFhackCExport command_result df_vectors (Core * c, vector <string> & parameters)
+{
+    Console & con = c->con;
+
+    if (parameters.size() != 2)
+    {
+        usage(con);
+        return CR_FAILURE;
+    }
+
+    uint32_t start = 0, bytes = 0;
+
+    if (!hexOrDec(parameters[0], start))
+    {
+        usage(con);
+        return CR_FAILURE;
+    }
+    
+    if (!hexOrDec(parameters[1], bytes))
+    {
+        usage(con);
+        return CR_FAILURE;
+    }
+
+    uint32_t end = start + bytes;
+
+    // 4 byte alignment.
+    while (start % 4 != 0)
+        start++;
+
+    c->Suspend();
+
+    std::vector<t_memrange> ranges;
+    std::vector<t_memrange> heap_ranges;
+    c->p->getMemRanges(ranges);
+
+    bool startInRange = false;
+
+    for (size_t i = 0; i < ranges.size(); i++)
+    {
+        t_memrange &range = ranges[i];
+
+        // Some kernels don't report [heap], and the heap can consist of
+        // more segments than just the one labeled with [heap], so include
+        // all segments which *might* be part of the heap.
+        if (range.read && range.write && !range.shared)
+        {
+            if (strlen(range.name) == 0 || strcmp(range.name, "[heap]") == 0)
+                heap_ranges.push_back(range);
+        }
+
+        if (!range.isInRange(start))
+            continue;
+
+        // Found the range containing the start
+        if (!range.isInRange(end))
+        {
+            con.print("Scanning %u bytes would read past end of memory "
+                      "range.\n", bytes);
+            uint32_t diff = end - range.end;
+            con.print("Cutting bytes down by %u.\n", diff);
+
+            end = (uint32_t) range.end;
+        }
+        startInRange = true;
+    } // for (size_t i = 0; i < ranges.size(); i++)
+
+    if (!startInRange)
+    {
+        con << "Address not in any memory range." << std::endl;
+        c->Resume();
+        return CR_FAILURE;
+    }
+
+    if (heap_ranges.empty())
+    {
+        con << "No possible heap segments." << std::endl;
+        c->Resume();
+        return CR_FAILURE;
+    }
+
+    uint32_t pos = start;
+
+    const uint32_t ptr_size = sizeof(void*);
+
+    for (uint32_t pos = start; pos < end; pos += ptr_size)
+    {
+        // Is it an embeded vector?
+        if (pos <= ( end - sizeof(t_vecTriplet) ))
+        {
+            t_vecTriplet* vec = (t_vecTriplet*) pos;
+
+            if (mightBeVec(heap_ranges, vec))
+            {
+                printVec(con, "VEC:", vec, start, pos);
+                // Skip over rest of vector.
+                pos += sizeof(t_vecTriplet) - ptr_size;
+                continue;
+            }
+        }
+
+        // Is it a vector pointer?
+        if (pos <= (end - ptr_size))
+        {
+            uint32_t ptr = * ( (uint32_t*) pos);
+
+            if (inAnyRange(heap_ranges, ptr))
+            {
+                t_vecTriplet* vec = (t_vecTriplet*) ptr;
+
+                if (mightBeVec(heap_ranges, vec))
+                {
+                    printVec(con, "VEC PTR:", vec, start, pos);
+                    continue;
+                }
+            }
+        }
+    } // for (uint32_t pos = start; pos < end; pos += ptr_size)
+
+    c->Resume();
+    return CR_OK;
+}