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
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
#include "../../cache.h"
#include "../../json-writer.h"
#include "lazyload.h"
#include <Psapi.h>
#include <tlHelp32.h>
/*
* An arbitrarily chosen value to limit the size of the ancestor
* array built in git_processes().
*/
#define NR_PIDS_LIMIT 10
/*
* Find the process data for the given PID in the given snapshot
* and update the PROCESSENTRY32 data.
*/
static int find_pid(DWORD pid, HANDLE hSnapshot, PROCESSENTRY32 *pe32)
{
pe32->dwSize = sizeof(PROCESSENTRY32);
if (Process32First(hSnapshot, pe32)) {
do {
if (pe32->th32ProcessID == pid)
return 1;
} while (Process32Next(hSnapshot, pe32));
}
return 0;
}
/*
* Accumulate JSON array of our parent processes:
* [
* exe-name-parent,
* exe-name-grand-parent,
* ...
* ]
*
* Note: we only report the filename of the process executable; the
* only way to get its full pathname is to use OpenProcess()
* and GetModuleFileNameEx() or QueryfullProcessImageName()
* and that seems rather expensive (on top of the cost of
* getting the snapshot).
*
* Note: we compute the set of parent processes by walking the PPID
* link in each visited PROCESSENTRY32 record. This search
* stops when an ancestor process is not found in the snapshot
* (because it exited before the current or intermediate parent
* process exited).
*
* This search may compute an incorrect result if the PPID link
* refers to the PID of an exited parent and that PID has been
* recycled and given to a new unrelated process.
*
* Worse, it is possible for a child or descendant of the
* current process to be given the recycled PID and cause a
* PPID-cycle. This would cause an infinite loop building our
* parent process array.
*
* Note: for completeness, the "System Idle" process has PID=0 and
* PPID=0 and could cause another PPID-cycle. We don't expect
* Git to be a descendant of the idle process, but because of
* PID recycling, it might be possible to get a PPID link value
* of 0. This too would cause an infinite loop.
*
* Therefore, we keep an array of the visited PPIDs to guard against
* cycles.
*
* We use a fixed-size array rather than ALLOC_GROW to keep things
* simple and avoid the alloc/realloc overhead. It is OK if we
* truncate the search and return a partial answer.
*/
static void get_processes(struct json_writer *jw, HANDLE hSnapshot)
{
PROCESSENTRY32 pe32;
DWORD pid;
DWORD pid_list[NR_PIDS_LIMIT];
int k, nr_pids = 0;
pid = GetCurrentProcessId();
while (find_pid(pid, hSnapshot, &pe32)) {
/* Only report parents. Omit self from the JSON output. */
if (nr_pids)
jw_array_string(jw, pe32.szExeFile);
/* Check for cycle in snapshot. (Yes, it happened.) */
for (k = 0; k < nr_pids; k++)
if (pid == pid_list[k]) {
jw_array_string(jw, "(cycle)");
return;
}
if (nr_pids == NR_PIDS_LIMIT) {
jw_array_string(jw, "(truncated)");
return;
}
pid_list[nr_pids++] = pid;
pid = pe32.th32ParentProcessID;
}
}
/*
* Emit JSON data for the current and parent processes. Individual
* trace2 targets can decide how to actually print it.
*/
static void get_ancestry(void)
{
HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if (hSnapshot != INVALID_HANDLE_VALUE) {
struct json_writer jw = JSON_WRITER_INIT;
jw_array_begin(&jw, 0);
get_processes(&jw, hSnapshot);
jw_end(&jw);
trace2_data_json("process", the_repository, "windows/ancestry",
&jw);
jw_release(&jw);
CloseHandle(hSnapshot);
}
}
/*
* Is a debugger attached to the current process?
*
* This will catch debug runs (where the debugger started the process).
* This is the normal case. Since this code is called during our startup,
* it will not report instances where a debugger is attached dynamically
* to a running git process, but that is relatively rare.
*/
static void get_is_being_debugged(void)
{
if (IsDebuggerPresent())
trace2_data_intmax("process", the_repository,
"windows/debugger_present", 1);
}
/*
* Emit JSON data with the peak memory usage of the current process.
*/
static void get_peak_memory_info(void)
{
DECLARE_PROC_ADDR(psapi.dll, BOOL, GetProcessMemoryInfo, HANDLE,
PPROCESS_MEMORY_COUNTERS, DWORD);
if (INIT_PROC_ADDR(GetProcessMemoryInfo)) {
PROCESS_MEMORY_COUNTERS pmc;
if (GetProcessMemoryInfo(GetCurrentProcess(), &pmc,
sizeof(pmc))) {
struct json_writer jw = JSON_WRITER_INIT;
jw_object_begin(&jw, 0);
#define KV(kv) #kv, (intmax_t)pmc.kv
jw_object_intmax(&jw, KV(PageFaultCount));
jw_object_intmax(&jw, KV(PeakWorkingSetSize));
jw_object_intmax(&jw, KV(PeakPagefileUsage));
jw_end(&jw);
trace2_data_json("process", the_repository,
"windows/memory", &jw);
jw_release(&jw);
}
}
}
void trace2_collect_process_info(enum trace2_process_info_reason reason)
{
if (!trace2_is_enabled())
return;
switch (reason) {
case TRACE2_PROCESS_INFO_STARTUP:
get_is_being_debugged();
get_ancestry();
return;
case TRACE2_PROCESS_INFO_EXIT:
get_peak_memory_info();
return;
default:
BUG("trace2_collect_process_info: unknown reason '%d'", reason);
}
}
|
