Adding source code to RetrieveSymbols for PE/PDB retrieval.

tools/win/RetrieveSymbols/RetrieveSymbols.cpp

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Symbol downloading demonstration code.
+// For more information see ReadMe.txt and this blog post:
+// https://randomascii.wordpress.com/2013/03/09/symbols-the-microsoft-way/
+
+#include "stdio.h"

[zturner, 2015/02/24 23:53:07]

Minor nit: any reason you chose to use quote syntax here?

[brucedawson, 2015/02/25 00:15:21]

Copy paste error I think. Fixed.

+#include <Windows.h>
+#include <DbgHelp.h>
+#include <string>
+
+// Link with the dbghelp import library
+#pragma comment(lib, "dbghelp.lib")
+
+// Uncomment this line to test with known-good parameters.
+//#define TESTING
+
+int main(int argc, char* argv[])
+{
+   // Tell dbghelp to print diagnostics to the debugger output.
+   SymSetOptions(SYMOPT_DEBUG);
+
+   // Initialize dbghelp
+   const HANDLE fakeProcess = (HANDLE)1;
+   BOOL result = SymInitialize(fakeProcess, NULL, FALSE);
+
+#ifdef TESTING
+   // Set a search path and cache directory. If this isn't set
+   // then _NT_SYMBOL_PATH will be used instead.
+   // Force setting it here to make sure that the test succeeds.
+   SymSetSearchPath(fakeProcess,
+              "SRV*c:\\symbolstest*http://msdl.microsoft.com/download/symbols");
+
+   // Valid PDB data to test the code.
+   std::string gText = "072FF0EB54D24DFAAE9D13885486EE09";

[zturner, 2015/02/24 23:53:07]

Is this supposed to be called gTextArg?  Looks like it won't compile as is with
TESTING

[brucedawson, 2015/02/25 00:15:21]

Good catch. I fixed that and verified that the TESTING version compiles and
works correctly now.

+   const char* ageText = "2";
+   const char* fileName = "kernel32.pdb";
+
+   // Valid PE data to test the code
+   fileName = "crypt32.dll";
+   const char* dateStampText = "4802A0D7";
+   const char* sizeText = "95000";
+   //fileName = "chrome_child.dll";
+   //const char* dateStampText = "5420D824";
+   //const char* sizeText = "20a6000";
+#else
+   if (argc < 4)
+   {
+       printf("Error: insufficient arguments.\n");
+       printf("Usage: %s guid age pdbname\n", argv[0]);
+       printf("Usage: %s dateStamp size pename\n", argv[0]);
+       printf("Example: %s 6720c31f4ac24f3ab0243e0641a4412f 1 "
+              "chrome_child.dll.pdb\n", argv[0]);
+       printf("Example: %s 4802A0D7 95000 crypt32.dll\n", argv[0]);
+       return 0;
+   }
+
+   std::string gTextArg = argv[1];
+   const char* dateStampText = argv[1];
+   const char* ageText = argv[2];
+   const char* sizeText = argv[2];
+   const char* fileName = argv[3];
+#endif
+
+   // Parse the GUID and age from the text
+   GUID g = {};
+   DWORD age = 0;
+   DWORD dateStamp = 0;
+   DWORD size = 0;
+
+   // Settings for SymFindFileInPath
+   void* id = nullptr;
+   DWORD flags = 0;
+   DWORD two = 0;
+
+   const char* ext = strrchr(fileName, '.');
+   if (!ext)
+   {
+     printf("No extension found on %s. Fatal error.\n", fileName);
+     return 0;
+   }
+
+   if (_stricmp(ext, ".pdb") == 0)
+   {
+     std::string gText;

[zturner, 2015/02/24 23:53:07]

How about GUIDFromString()?  Removes almost this entire if branch.

[brucedawson, 2015/02/25 00:15:22]

I looked at that function before and it seemed... problematic. The documentation
says it isn't exported or declared and may disappear. And those functions seem
to have very strict formatting requirements, which takes some of the fun out of
it.

It is odd that there isn't a trivially available, well documented, powerful and
flexible way to handle this operation.

[zturner, 2015/02/25 00:29:33]

Ahh yea, I didn't notice that.  There's CLSIDFromString, but then you have to do
a wide char conversion.  Bleh.

+     // Scan the GUID argument and remove all non-hex characters. This allows
+     // passing GUIDs with '-', '{', and '}' characters.
+     for (auto c : gTextArg)
+     {
+       if (isxdigit(c))
+       {
+         gText.push_back(c);
+       }
+     }
+     printf("Parsing symbol data for a PDB file.\n");
+     if (gText.size() != 32)
+     {
+         printf("Error: GUIDs must be exactly 32 characters"
+                " (%s was stripped to %s).\n", gTextArg.c_str(), gText.c_str());
+         return 10;
+     }
+
+     int count = sscanf_s(gText.substr(0, 8).c_str(), "%x", &g.Data1);
+     DWORD temp;
+     count += sscanf_s(gText.substr(8, 4).c_str(), "%x", &temp);
+     g.Data2 = (unsigned short)temp;
+     count += sscanf_s(gText.substr(12, 4).c_str(), "%x", &temp);
+     g.Data3 = (unsigned short)temp;
+     for (auto i = 0; i < ARRAYSIZE(g.Data4); ++i)
+     {
+         count += sscanf_s(gText.substr(16 + i * 2, 2).c_str(), "%x", &temp);
+         g.Data4[i] = (unsigned char)temp;
+     }
+     count += sscanf_s(ageText, "%x", &age);
+
+     if (count != 12)
+     {
+         printf("Error: couldn't parse the GUID/age string. Sorry.\n");
+         return 10;
+     }
+     flags = SSRVOPT_GUIDPTR;
+     id = &g;
+     two = age;
+     printf("Looking for %s %s %s.\n", gText.c_str(), ageText, fileName);
+   }
+   else
+   {
+     printf("Parsing symbol data for a PE (.dll or .exe) file.\n");
+     if (strlen(dateStampText) != 8)
+       printf("Warning!!! The datestamp (%s) is not eight characters long. "
+              "This is usually wrong.\n", dateStampText);
+     int count = sscanf_s(dateStampText, "%x", &dateStamp);
+     count += sscanf_s(sizeText, "%x", &size);
+     flags = SSRVOPT_DWORDPTR;
+     id = &dateStamp;
+     two = size;
+     printf("Looking for %s %x %x.\n", fileName, dateStamp, two);
+   }
+
+   char filePath[MAX_PATH] = {};
+   DWORD three = 0;
+
+   if (SymFindFileInPath(fakeProcess, NULL, fileName, id, two, three,
+               flags, filePath, NULL, NULL))
+   {
+       printf("Found symbol file - placed it in %s.\n", filePath);
+   }
+   else
+   {
+       printf("Error: symbols not found - error %u. Are dbghelp.dll and "
+               "symsrv.dll in the same directory as this executable?\n",
+               GetLastError());
+       printf("Note that symbol server lookups sometimes fail randomly. "
+              "Try again?\n");
+   }
+
+   SymCleanup(fakeProcess);
+
+   return 0;
+}