1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
/*-------------------------------------------------------------------------
*
* win32_crashdump.c
* Automatic crash dump creation for PostgreSQL on Windows
*
* The crashdump feature traps unhandled win32 exceptions produced by the
* backend, and tries to produce a Windows MiniDump crash
* dump for later debugging and analysis. The machine performing the dump
* doesn't need any special debugging tools; the user only needs to send
* the dump to somebody who has the same version of PostgreSQL and has debugging
* tools.
*
* crashdump module originally by Craig Ringer <ringerc@ringerc.id.au>
*
* LIMITATIONS
* ===========
* This *won't* work in hard OOM situations or stack overflows.
*
* For those, it'd be necessary to take a much more complicated approach where
* the handler switches to a new stack (if it can) and forks a helper process
* to debug it self.
*
* POSSIBLE FUTURE WORK
* ====================
* For bonus points, the crash dump format permits embedding of user-supplied
* data. If there's anything else that should always be supplied with a crash
* dump (postgresql.conf? Last few lines of a log file?), it could potentially
* be added, though at the cost of a greater chance of the crash dump failing.
*
*
* Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/backend/port/win32/crashdump.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <string.h>
#include <dbghelp.h>
/*
* Much of the following code is based on CodeProject and MSDN examples,
* particularly
* http://www.codeproject.com/KB/debug/postmortemdebug_standalone1.aspx
*
* Useful MSDN articles:
*
* http://msdn.microsoft.com/en-us/library/ff805116(v=VS.85).aspx
* http://msdn.microsoft.com/en-us/library/ms679294(VS.85).aspx
*
* Other useful articles on working with minidumps:
* http://www.debuginfo.com/articles/effminidumps.html
*/
typedef BOOL (WINAPI * MINIDUMPWRITEDUMP) (HANDLE hProcess, DWORD dwPid, HANDLE hFile, MINIDUMP_TYPE DumpType,
CONST PMINIDUMP_EXCEPTION_INFORMATION ExceptionParam,
CONST PMINIDUMP_USER_STREAM_INFORMATION UserStreamParam,
CONST PMINIDUMP_CALLBACK_INFORMATION CallbackParam
);
/*
* This function is the exception handler passed to SetUnhandledExceptionFilter.
* It's invoked only if there's an unhandled exception. The handler will use
* dbghelp.dll to generate a crash dump, then resume the normal unhandled
* exception process, which will generally exit with an error message from
* the runtime.
*
* This function is run under the unhandled exception handler, effectively
* in a crash context, so it should be careful with memory and avoid using
* any PostgreSQL functions.
*/
static LONG WINAPI
crashDumpHandler(struct _EXCEPTION_POINTERS * pExceptionInfo)
{
/*
* We only write crash dumps if the "crashdumps" directory within the
* postgres data directory exists.
*/
DWORD attribs = GetFileAttributesA("crashdumps");
if (attribs != INVALID_FILE_ATTRIBUTES && (attribs & FILE_ATTRIBUTE_DIRECTORY))
{
/* 'crashdumps' exists and is a directory. Try to write a dump' */
HMODULE hDll = NULL;
MINIDUMPWRITEDUMP pDump = NULL;
MINIDUMP_TYPE dumpType;
char dumpPath[_MAX_PATH];
HANDLE selfProcHandle = GetCurrentProcess();
DWORD selfPid = GetProcessId(selfProcHandle);
HANDLE dumpFile;
DWORD systemTicks;
struct _MINIDUMP_EXCEPTION_INFORMATION ExInfo;
ExInfo.ThreadId = GetCurrentThreadId();
ExInfo.ExceptionPointers = pExceptionInfo;
ExInfo.ClientPointers = FALSE;
/* Load the dbghelp.dll library and functions */
hDll = LoadLibrary("dbghelp.dll");
if (hDll == NULL)
{
write_stderr("could not load dbghelp.dll, cannot write crash dump\n");
return EXCEPTION_CONTINUE_SEARCH;
}
pDump = (MINIDUMPWRITEDUMP) GetProcAddress(hDll, "MiniDumpWriteDump");
if (pDump == NULL)
{
write_stderr("could not load required functions in dbghelp.dll, cannot write crash dump\n");
return EXCEPTION_CONTINUE_SEARCH;
}
/*
* Dump as much as we can, except shared memory, code segments, and
* memory mapped files. Exactly what we can dump depends on the
* version of dbghelp.dll, see:
* http://msdn.microsoft.com/en-us/library/ms680519(v=VS.85).aspx
*/
dumpType = MiniDumpNormal | MiniDumpWithHandleData |
MiniDumpWithDataSegs;
if (GetProcAddress(hDll, "EnumDirTree") != NULL)
{
/* If this function exists, we have version 5.2 or newer */
dumpType |= MiniDumpWithIndirectlyReferencedMemory |
MiniDumpWithPrivateReadWriteMemory;
}
systemTicks = GetTickCount();
snprintf(dumpPath, _MAX_PATH,
"crashdumps\\postgres-pid%0i-%0i.mdmp",
(int) selfPid, (int) systemTicks);
dumpPath[_MAX_PATH - 1] = '\0';
dumpFile = CreateFile(dumpPath, GENERIC_WRITE, FILE_SHARE_WRITE,
NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL,
NULL);
if (dumpFile == INVALID_HANDLE_VALUE)
{
write_stderr("could not open crash dump file \"%s\" for writing: error code %lu\n",
dumpPath, GetLastError());
return EXCEPTION_CONTINUE_SEARCH;
}
if ((*pDump) (selfProcHandle, selfPid, dumpFile, dumpType, &ExInfo,
NULL, NULL))
write_stderr("wrote crash dump to file \"%s\"\n", dumpPath);
else
write_stderr("could not write crash dump to file \"%s\": error code %lu\n",
dumpPath, GetLastError());
CloseHandle(dumpFile);
}
return EXCEPTION_CONTINUE_SEARCH;
}
void
pgwin32_install_crashdump_handler(void)
{
SetUnhandledExceptionFilter(crashDumpHandler);
}
|
