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
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
/*
* Copyright © 2021 Willian Henrique <wsimanbrazil@yahoo.com.br>
* Copyright © 2021 Michael Smith <mikesmiffy128@gmail.com>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#include <stdbool.h>
#include "con_.h"
#include "hook.h"
#include "gamedata.h"
#include "intdefs.h"
#include "mem.h"
#include "os.h"
#include "udis86.h"
#include "vcall.h"
#define SIGNONSTATE_SPAWN 5 // ready to receive entity packets
#define SIGNONSTATE_FULL 6 // fully connected, first non-delta packet receieved
typedef void (*VCALLCONV f_StopRecording)(void *);
typedef void (*VCALLCONV f_SetSignonState)(void *, int);
static void *demorecorder;
static struct con_cmd *cmd_stop;
static bool *recording;
static int *demonum;
static f_SetSignonState orig_SetSignonState;
static f_StopRecording orig_StopRecording;
static con_cmdcb orig_stop_callback;
static int auto_demonum = 1;
static bool auto_recording = false;
DEF_CVAR(sst_autorecord, "Continue recording demos through map changes",
"0", CON_ARCHIVE | CON_HIDDEN)
static void VCALLCONV hook_StopRecording(void *this) {
// This hook will get called twice per loaded save (in most games/versions,
// at least, according to SAR people): first with m_bLoadgame set to false
// and then with it set to true. This will set m_nDemoNumber to 0 and
// m_bRecording to false
orig_StopRecording(this);
if (auto_recording && con_getvari(sst_autorecord)) {
*demonum = auto_demonum;
*recording = true;
}
else {
auto_demonum = 1;
auto_recording = false;
}
}
static void VCALLCONV hook_SetSignonState(void *this, int state) {
// SIGNONSTATE_FULL *may* happen twice per load, depending on the game, so
// use SIGNONSTATE_SPAWN for demo number increase
if (state == SIGNONSTATE_SPAWN && auto_recording) auto_demonum++;
// Starting a demo recording will call this function with SIGNONSTATE_FULL
// After a load, the engine's demo recorder will only start recording when
// it reaches this state, so this is a good time to set the flag if needed
else if (state == SIGNONSTATE_FULL) {
// Changing sessions may unset the recording flag (or so says NeKzor),
// so if we want to be recording, we want to tell the engine to record.
// But also, if the engine is already recording, we want our state to
// reflect *that*. IOW, if either thing is set, also set the other one.
auto_recording |= *recording; *recording = auto_recording;
// FIXME: this will override demonum incorrectly if the plugin is
// loaded while demos are already being recorded
if (auto_recording) *demonum = auto_demonum;
}
orig_SetSignonState(this, state);
}
static void hook_stop_callback(const struct con_cmdargs *args) {
auto_recording = false;
orig_stop_callback(args);
}
// This finds the "demorecorder" global variable (the engine-wide CDemoRecorder
// instance).
static inline void *find_demorecorder(struct con_cmd *cmd_stop) {
// The "stop" command calls the virtual function demorecorder.IsRecording(),
// so just look for the load of the "this" pointer
struct ud udis;
ud_init(&udis);
ud_set_mode(&udis, 32);
ud_set_input_buffer(&udis, (uchar *)con_getcmdcb(cmd_stop), 32);
while (ud_disassemble(&udis)) {
#ifdef _WIN32
if (ud_insn_mnemonic(&udis) == UD_Imov) {
const struct ud_operand *dest = ud_insn_opr(&udis, 0);
const struct ud_operand *src = ud_insn_opr(&udis, 1);
// looking for a mov from an address into ECX, as per thiscall
if (dest->type == UD_OP_REG && dest->base == UD_R_ECX &&
src->type == UD_OP_MEM) {
return *(void **)src->lval.udword;
}
}
#else
#error TODO(linux): implement linux equivalent (cdecl!)
#endif
}
return 0;
}
// This finds "m_bRecording" and "m_nDemoNumber" using the pointer to the
// original "StopRecording" demorecorder function
static inline bool find_recmembers(void *stop_recording_func, void *demorec) {
struct ud udis;
ud_init(&udis);
ud_set_mode(&udis, 32);
// TODO(opt): consider the below: is it really needed? does it matter?
// way overshooting the size of the function in bytes to make sure it
// accomodates for possible differences in different games. we make sure
// to stop early if we find a RET so should be fine
ud_set_input_buffer(&udis, (uchar *)stop_recording_func, 200);
while (ud_disassemble(&udis)) {
#ifdef _WIN32
enum ud_mnemonic_code code = ud_insn_mnemonic(&udis);
if (code == UD_Imov) {
const struct ud_operand *dest = ud_insn_opr(&udis, 0);
const struct ud_operand *src = ud_insn_opr(&udis, 1);
// m_nDemoNumber and m_bRecording are both set to 0
// looking for movs with immediates equal to 0
// the byte immediate refers to m_bRecording
if (src->type == UD_OP_IMM && src->lval.ubyte == 0) {
if (src->size == 8) {
recording = (bool *)mem_offset(demorec, dest->lval.udword);
}
else {
demonum = (int *)mem_offset(demorec, dest->lval.udword);
}
if (recording && demonum) return true; // blegh
}
}
else if (code == UD_Iret) {
return false;
}
#else // linux is probably different here idk
#error TODO(linux): implement linux equivalent
#endif
}
return false;
}
bool demorec_init(void) {
if (!gamedata_has_vtidx_SetSignonState ||
!gamedata_has_vtidx_StopRecording) {
con_warn("demorec: missing gamedata entries for this engine\n");
return false;
}
cmd_stop = con_findcmd("stop");
if (!cmd_stop) { // can *this* even happen? I hope not!
con_warn("demorec: couldn't find \"stop\" command\n");
return false;
}
demorecorder = find_demorecorder(cmd_stop);
if (!demorecorder) {
con_warn("demorec: couldn't find demo recorder instance\n");
return false;
}
void **vtable = *(void ***)demorecorder;
// XXX: 16 is totally arbitrary here! figure out proper bounds later
if (!os_mprot(vtable, 16 * sizeof(void *), PAGE_EXECUTE_READWRITE)) {
#ifdef _WIN32
char err[128];
OS_WINDOWS_ERROR(err);
#else
const char *err = strerror(errno);
#endif
con_warn("demorec: couldn't unprotect CDemoRecorder vtable: %s\n", err);
return false;
}
if (!find_recmembers(vtable[7], demorecorder)) {
con_warn("demorec: couldn't find m_bRecording and m_nDemoNumber\n");
return false;
}
orig_SetSignonState = (f_SetSignonState)hook_vtable(vtable,
gamedata_vtidx_SetSignonState, (void *)&hook_SetSignonState);
orig_StopRecording = (f_StopRecording)hook_vtable(vtable,
gamedata_vtidx_StopRecording, (void *)&hook_StopRecording);
orig_stop_callback = cmd_stop->cb;
cmd_stop->cb = &hook_stop_callback;
sst_autorecord->base.flags &= ~CON_HIDDEN;
return true;
}
void demorec_end(void) {
void **vtable = *(void ***)demorecorder;
unhook_vtable(vtable, gamedata_vtidx_SetSignonState,
(void *)orig_SetSignonState);
unhook_vtable(vtable, gamedata_vtidx_StopRecording,
(void *)orig_StopRecording);
cmd_stop->cb = orig_stop_callback;
}
// vi: sw=4 ts=4 noet tw=80 cc=80
|
