collect minidump if it chrashes

tools/win_dbghelp.cpp

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifdef SK_BUILD_FOR_WIN32
+
+#include "windows.h"
+#include "win_dbghelp.h"
+#include <process.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+// Remove prefix addresses. 18 = 2 * (8 digit hexa + 1 space).
+// e.g. "01234567 01234567 render_pdf!processInput

[epoger, 2013/03/08 16:12:42]

General suggestion, nothing necessarily needed here: IMHO, when we are making up
hexadecimal values, I would recommend including at least some a-f digits to make
it clearer that it's hexadecimal!

[edisonn, 2013/03/08 16:44:25]

Done.

+#define CDB_CALLSTACK_PREFIX (18)
+
+// CDB.EXE prints a lot of garbage and there is no argument to pass which
+// would remove all that noise.
+// Using eval feature that evaluates a number in hex and prints it to stdout
+// to mark where the callstack is printed.
+// For example, each thread's callstack will be marked with "12340000" at
+// the beginning and "12340001" at the end.
+// We just made up these numbers; they could be anything, as long as they
+// match up with their decimal equivalents.
+
+#define MARKER_THREAD_CALLSTACK_START_NUMBER "12340000"
+#define MARKER_THREAD_CALLSTACK_START "Evaluate expression: 305397760 = 12340000"
+
+#define MARKER_THREAD_CALLSTACK_STOP_NUMBER "12340001"
+#define MARKER_THREAD_CALLSTACK_STOP "Evaluate expression: 305397761 = 12340001"
+
+#define MARKER_EXCEPTION_CALLSTACK_START_NUMBER "12340002"
+#define MARKER_EXCEPTION_CALLSTACK_START "Evaluate expression: 305397762 = 12340002"
+
+#define MARKER_EXCEPTION_CALLSTACK_STOP_NUMBER "12340003"
+#define MARKER_EXCEPTION_CALLSTACK_STOP "Evaluate expression: 305397763 = 12340003"
+
+// k - print stack
+// ? val - evaluate expression. Used to mark the log file.
+// .ecxr - load exception, if exception was thrown.
+// k - print the resolved stack by .ecxr
+// q - quit cdb.exe
+#define CDB_PRINT_CALLSTACK_CURRENT_THREAD "? " MARKER_THREAD_CALLSTACK_START_NUMBER "; k; ? " MARKER_THREAD_CALLSTACK_STOP_NUMBER "; .ecxr; ? " MARKER_EXCEPTION_CALLSTACK_START_NUMBER "; k; ? " MARKER_EXCEPTION_CALLSTACK_STOP_NUMBER "; q"
+
+static void strncpyOrSetBlank(char* dest, const char* src, size_t len) {

[epoger, 2013/03/08 16:12:42]

I had hoped that, if you passed in dest as char[] instead of char *, you could
move the sizeof(dest) into this function.  But you can't. :-( Details at
http://stackoverflow.com/questions/37538/how-do-i-determine-the-size-of-my-ar...

If you want to eliminate the hazard of passing the wrong len value, I guess you
could make a macro like this:

#define STRNCPY_OR_SET_BLANK(dest, src) strnpyOrSetBlank((dest), (src),
sizeof(dest))

[edisonn, 2013/03/08 16:44:25]

the problem is that someone might allocate dynamically the string in a new
version, and then mess up the strcpy. I prefer to keep it explicitly.

But we could switch to using language D which has goodies like that AFAIK

On 2013/03/08 16:12:42, epoger wrote:

[epoger, 2013/03/08 16:52:32]

Makes sense.  Thanks for evaluating it.
Let's leave that for a separate CL. :-)

+  const char* srcOrEmptyString = (NULL == src) ? "" : src;
+  strncpy(dest, srcOrEmptyString, len);
+}
+
+char debug_app_name[MAX_PATH] = "";
+void setAppName(const char* app_name) { 
+    strncpyOrSetBlank(debug_app_name, app_name, sizeof(debug_app_name));
+}
+
+const char* getAppName() {
+    return debug_app_name;
+}
+
+char debug_binaries_path[MAX_PATH] = "";
+void setBinariesPath(const char* binaries_path) {
+    strncpyOrSetBlank(debug_binaries_path, binaries_path,
+                      sizeof(debug_binaries_path));
+}
+
+const char* getBinariesPath() {
+    return debug_binaries_path;
+}
+
+char debug_app_version[100] = "";
+void setAppVersion(const char* version) {
+    strncpyOrSetBlank(debug_app_version, version, sizeof(debug_app_version));
+}
+
+const char* getAppVersion() {
+    return debug_app_version;
+}
+
+char debug_cdb_path[MAX_PATH] = "";
+void setCdbPath(const char* path) {
+  strncpyOrSetBlank(debug_cdb_path, path, sizeof(debug_cdb_path));
+}
+
+const char* getCdbPath() {
+    return debug_cdb_path;
+}
+
+/** Print all the lines of a CDB k command whicha are callstacks.
+ *  Callstack lines are marked by start and stop markers and they are prefixed
+ *  byt 2 hex adresses, which will not be reported.
+ */
+static void printCallstack(const char* filename,
+                           const char* start,
+                           const char* stop) {
+    FILE* file = fopen(filename, "rt");
+    char line[1000];
+    bool started = false;
+    // Not the most performant code, but this will be used only to collect
+    // the callstack from a log files, only when the application had failed.
+    while (fgets(line, sizeof(line), file)) {
+        if (!started && strncmp(start, line, strlen(start)) == 0) {
+            started = true;
+        } else if (started && strncmp(stop, line, strlen(stop)) == 0) {
+            break;
+        } else if (started) {
+            // Filter messages. Calstack lines contain "exe/dll!function"
+            if (strchr(line, '!') != NULL && strlen(line) > CDB_CALLSTACK_PREFIX) {
+                printf("%s", line + CDB_CALLSTACK_PREFIX);  // fgets includes \n already.
+            }
+        }
+    }
+    fclose(file);
+}
+
+#define BUILD_UNIQUE_FILENAME(var, ext, szPath, szAppName, szVersion, stLocalTime) \
+    sprintf(szFileName, "%s%s\\%s-%04d%02d%02d-%02d%02d%02d-%ld-%ld" ext, \
+           szPath, szAppName, szVersion, \
+           stLocalTime.wYear, stLocalTime.wMonth, stLocalTime.wDay, \
+           stLocalTime.wHour, stLocalTime.wMinute, stLocalTime.wSecond, \
+           GetCurrentProcessId(), GetCurrentThreadId()); 
+
+// Exception execution handler.  Exception is recognized. Transfer control to
+// the exception handler by executing the __except compound statement,
+// then continue execution after the __except block.
+int GenerateDumpAndPrintCallstack(EXCEPTION_POINTERS* pExceptionPointers) {
+    BOOL bMiniDumpSuccessful;
+    char szPath[MAX_PATH]; 
+    char szFileName[MAX_PATH]; 
+    char szFileNameOutput[MAX_PATH]; 
+    const char* szAppName = getAppName();
+    const char* szVersion = getAppVersion();
+    DWORD dwBufferSize = MAX_PATH;
+    HANDLE hDumpFile;
+    SYSTEMTIME stLocalTime;
+    MINIDUMP_EXCEPTION_INFORMATION ExpParam;
+
+    GetLocalTime( &stLocalTime );
+    GetTempPath( dwBufferSize, szPath );
+
+    sprintf( szFileName, "%s%s", szPath, szAppName );
+    CreateDirectory( szFileName, NULL );
+
+    BUILD_UNIQUE_FILENAME(szFileName, ".dmp", szPath, szAppName, szVersion, stLocalTime);
+    BUILD_UNIQUE_FILENAME(szFileNameOutput, ".out", szPath, szAppName, szVersion, stLocalTime);
+
+    hDumpFile = CreateFile(szFileName,
+                           GENERIC_READ|GENERIC_WRITE, 
+                           FILE_SHARE_WRITE|FILE_SHARE_READ,
+                           0,
+                           CREATE_ALWAYS,
+                           0,
+                           0);
+
+    ExpParam.ThreadId = GetCurrentThreadId();
+    ExpParam.ExceptionPointers = pExceptionPointers;
+    ExpParam.ClientPointers = TRUE;
+
+    bMiniDumpSuccessful = MiniDumpWriteDump(GetCurrentProcess(),
+                                            GetCurrentProcessId(), 
+                                            hDumpFile,
+                                            MiniDumpWithDataSegs,
+                                            &ExpParam,
+                                            NULL,
+                                            NULL);
+
+    printf("MiniDump file:    %s\n", szFileName);
+    printf("App exe and pdb:  %s\n", getBinariesPath());
+
+    const char* cdbExePath = getCdbPath();
+    if (cdbExePath && *cdbExePath != '\0') {
+        printf("Cdb exe:          %s\n", cdbExePath);
+      
+        char command[MAX_PATH * 4];
+        sprintf(command, "%s -y \"%s\" -i \"%s\" -z \"%s\" -c \"%s\" -kqm >\"%s\"",
+                cdbExePath,
+                getBinariesPath(),
+                getBinariesPath(),
+                szFileName,
+                CDB_PRINT_CALLSTACK_CURRENT_THREAD,
+                szFileNameOutput);
+        system(command);
+
+        printf("\nThread Callstack:\n");
+        printCallstack(szFileNameOutput, 
+                       MARKER_THREAD_CALLSTACK_START,
+                       MARKER_THREAD_CALLSTACK_STOP);
+
+        printf("\nException Callstack:\n");        
+        printCallstack(szFileNameOutput,
+                       MARKER_EXCEPTION_CALLSTACK_START,
+                       MARKER_EXCEPTION_CALLSTACK_STOP);
+    } else {
+        printf("Warning: CDB path not set up.\n");        
+    }
+
+    return EXCEPTION_EXECUTE_HANDLER;
+}
+
+/** Sets the debugging variables. Input parameter is app location.
+ *  e.g out\Debug\render_pdfs.exe
+ *  This function expects the .pdb file to be in the same directory.
+ */
+void setUpDebuggingFromArgs(const char* vargs0) {
+    int i = strlen(vargs0);
+
+    if (i >= 4 && stricmp(vargs0 - 4, ".exe") == 0) {
+        // Ignore .exe
+        i -= 4;
+    }
+
+    int pos_period = i;
+
+    // Find last \ in path - this is Windows!
+    while (i >= 0 && vargs0[i] != '\\') {
+        i--;
+    }
+
+    int pos_last_slash = i;
+
+    char app_name[MAX_PATH];
+    strncpy(app_name, vargs0 + pos_last_slash + 1, pos_period - pos_last_slash - 1);
+    app_name[pos_period - pos_last_slash] = '\0';
+    setAppName(app_name);
+
+    char binaries_path[MAX_PATH];
+    strncpy(binaries_path, vargs0, pos_last_slash);
+    binaries_path[pos_last_slash] = '\0';
+    setBinariesPath(binaries_path);
+
+    setAppVersion("1.0");  // Dummy for now, but use revision instead if we use
+                           // the minidump for anything else other than
+                           // collecting the callstack.
+
+    // cdb.exe is the app used to load the minidump which prints the callstack.
+    char cdbExePath[MAX_PATH];
+#ifdef _WIN64
+    sprintf(cdbExePath, "%s\\x64\\cdb.exe", SK_CDB_PATH);
+#else
+    sprintf(cdbExePath, "%s\\cdb.exe", SK_CDB_PATH);
+#endif
+    setCdbPath(cdbExePath);
+}
+
+#endif  // SK_BUILD_FOR_WIN32