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/*
* Copyright © 2023 Willian Henrique <wsimanbrazil@yahoo.com.br>
* Copyright © 2023 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 <string.h>
#include "con_.h"
#include "engineapi.h"
#include "ent.h"
#include "errmsg.h"
#include "feature.h"
#include "gamedata.h"
#include "gametype.h"
#include "intdefs.h"
#include "l4dmm.h"
#include "mem.h"
#include "vcall.h"
#include "x86.h"
#include "x86util.h"
#ifdef _WIN32
#define strcasecmp _stricmp
#endif
FEATURE("Left 4 Dead quick resetting")
REQUIRE(ent)
REQUIRE(l4dmm)
static void **votecontroller;
static int off_callerrecords = -1;
static int off_voteissues;
// Note: the vote callers vector contains these as elements. We don't currently
// do anything with the structure, but keeping it here for reference.
/*struct CallerRecord {
u32 steamid_trunc;
float last_time;
int votes_passed;
int votes_failed;
int last_issueidx;
bool last_passed;
};*/
// XXX: duping this again here... what makes sense to tidy this up?
#ifdef _WIN32
#define NVDTOR 1
#else
#define NVDTOR 2
#endif
struct CVoteIssue;
DECL_VFUNC(const char *, SetIssueDetails, 1 + NVDTOR, const char *)
DECL_VFUNC(const char *, GetDisplayString, 8 + NVDTOR)
DECL_VFUNC(const char *, ExecuteCommand, 9 + NVDTOR)
static struct CVoteIssue *getissue(const char *textkey) {
struct CUtlVector *issuevec = mem_offset(*votecontroller, off_voteissues);
struct CVoteIssue **issues = issuevec->m.mem;
for (int i = 0; /*i < issuevec->sz*/; ++i) { // key MUST be valid!
if (!strcmp(GetDisplayString(issues[i]), textkey)) return issues[i];
}
}
static void reset(void) {
// reset the vote cooldowns if possible (will skip L4D1). only necessary on
// versions >2045 and on map 1, but it's easiest to do unconditionally
if (off_callerrecords != -1) {
// Basically equivalent to CUtlVector::RemoveAll. The elements have no
// destructors to call. The resulting state is as if nobody has voted.
struct CUtlVector *recordvector = mem_offset(*votecontroller,
off_callerrecords);
recordvector->sz = 0;
}
struct CVoteIssue *issue = getissue("#L4D_vote_restart_game");
ExecuteCommand(issue);
}
static void change(const char *missionid) {
struct CVoteIssue *issue = getissue("#L4D_vote_mission_change");
SetIssueDetails(issue, missionid); // will just nop if invalid
ExecuteCommand(issue);
}
DEF_CCMD_HERE_UNREG(sst_l4d_quickreset,
"Reset (or switch) campaign and clear all vote cooldowns", 0) {
if (cmd->argc > 2) {
con_warn("usage: sst_l4d_quickreset [campaignid]\n");
return;
}
if (!*votecontroller) {
con_warn("not hosting a server\n");
return;
}
if (cmd->argc == 2) {
const char *cur = l4dmm_curcampaign();
if (!cur || strcasecmp(cur, cmd->argv[1])) {
change(cmd->argv[1]);
return;
}
}
reset();
}
PREINIT { return GAMETYPE_MATCHES(L4D); }
// This finds the g_voteController variable using the listissues callback, and
// returns a pointer to the rest of the bytes for find_voteissues() below
static inline const uchar *find_votecontroller(con_cmdcbv1 listissues_cb) {
const uchar *insns = (const uchar *)listissues_cb;
#ifdef _WIN32
// The "listissues" command calls CVoteController::ListIssues, loading
// g_voteController into ECX
for (const uchar *p = insns; p - insns < 32;) {
if (p[0] == X86_MOVRMW && p[1] == X86_MODRM(0, 1, 5)) {
votecontroller = mem_loadptr(p + 2);
return p;
}
NEXT_INSN(p, "g_voteController variable");
}
#else
#warning TODO(linux): this will be different
#endif
return 0;
}
// This finds ListIssues() using the instruction pointer returned by
// find_votecontroller() above, and then uses that to find the vote issue list.
static inline bool find_voteissues(const uchar *insns) {
#ifdef _WIN32
for (const uchar *p = insns; p - insns < 16;) {
// Look for the last call before the ret - that has to be ListIssues()
if (p[0] == X86_CALL && p[5] == X86_RET) {
insns = p + 5 + mem_loadoffset(p + 1);
goto ok;
}
NEXT_INSN(p, "ListIssues call");
}
return false;
ok: for (const uchar *p = insns; p - insns < 96;) {
// There's a virtual call on each actual CVoteIssue in the loop over the
// list. That entails putting the issue pointer in ECX, which involves
// loading that pointer from the vector, which exists at an offset from
// `this`, meaning we can find the offset from the mov into ECX.
if (p[0] == X86_MOVRMW && (p[1] & 0xF8) == 0x88) {
int off = mem_loadoffset(p + 2);
if (off > 800) { // sanity check: offset is always fairly high
off_voteissues = off;
return true;
}
}
// Further complication: at least in 2045 there's a short jmp over some
// invalid instruction bytes. I guess there's no reason to ever expect
// something interesting after an unconditional jmp, so just follow it.
if (p[0] == X86_JMPI8) {
p += 2 + ((s8 *)p)[1];
continue;
}
NEXT_INSN(p, "offset to vote issue vector");
}
#else
#warning TODO(linux): and also this
#endif
return false;
}
// This finds the caller record vector using a pointer to the
// CVoteController::Spawn function
static inline bool find_votecallers(void *votectrlspawn) {
#ifdef _WIN32
const uchar *insns = (const uchar *)votectrlspawn;
for (const uchar *p = insns; p - insns < 64;) {
// Unsure what the member on this offset actually is (the game seems to
// want it to be set to 0 to allow votes to happen), but the vector we
// want seems to consistently be 8 bytes after whatever this is
// "mov dword ptr [<reg> + off], 0", mod == 0b11
if (p[0] == X86_MOVMIW && (p[1] & 0xC0) == 0x80 &&
mem_load32(p + 6) == 0) {
off_callerrecords = mem_load32(p + 2) + 8;
return true;
}
NEXT_INSN(p, "offset to vote caller record vector");
}
#else
#warning TODO(linux): this too
#endif
return false;
}
INIT {
struct con_cmd *cmd_listissues = con_findcmd("listissues");
if (!cmd_listissues) {
errmsg_errorx("couldn't find \"listissues\" command");
return false;
}
con_cmdcbv1 listissues_cb = con_getcmdcbv1(cmd_listissues);
const uchar *nextinsns = find_votecontroller(listissues_cb);
if (!nextinsns) {
errmsg_errorx("couldn't find vote controller variable");
return false;
}
if (!find_voteissues(nextinsns)) {
errmsg_errorx("couldn't find vote issues list offset\n");
return false;
}
// only bother with vote cooldown stuff for L4D2, since all versions of L4D1
// have unlimited votes anyway. NOTE: assuming L4D2 always has Spawn in
// gamedata (which has no reason to stop being true...)
if (GAMETYPE_MATCHES(L4D2)) {
// g_voteController may have not been initialized yet so we get the
// vtable from the ent factory
const struct CEntityFactory *factory = ent_getfactory("vote_controller");
if (!factory) {
errmsg_errorx("couldn't find vote controller entity factory");
goto nocd;
}
void **vtable = ent_findvtable(factory, "CVoteController");
if (!vtable) {
errmsg_errorx("couldn't find CVoteController vtable");
goto nocd;
}
if (!find_votecallers(vtable[vtidx_Spawn])) {
errmsg_errorx("couldn't find vote callers list offset");
nocd: errmsg_note("resetting a first map will not clear vote cooldowns");
}
}
con_reg(sst_l4d_quickreset);
return true;
}
// vi: sw=4 ts=4 noet tw=80 cc=80
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