Initial public snapshot

With code from Bill. Thanks Bill!

1 files changed, 372 insertions, 0 deletions

diff --git a/src/gameinfo.c b/src/gameinfo.c
new file mode 100644
index 0000000..32f5051
--- /dev/null
+++ b/src/gameinfo.c
@@ -0,0 +1,372 @@
+/*
+ * 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 <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#ifdef _WIN32
+#include <shlwapi.h>
+#endif
+
+#include "con_.h"
+#include "intdefs.h"
+#include "kv.h"
+#include "os.h"
+
+// Formatting for os_char * -> char * (or vice versa) - needed for con_warn()s
+// with file paths, etc
+#ifdef _WIN32
+#define fS "S" // os string (wide string) to regular string
+#define Fs L"S" // regular string to os string (wide string)
+#else
+// everything is just a regular string already
+#define fS "s"
+#define Fs "s"
+#endif
+
+static os_char exedir[PATH_MAX];
+static os_char gamedir[PATH_MAX];
+static char _gameinfo_title[64] = {0};
+const char *gameinfo_title = _gameinfo_title;
+static os_char _gameinfo_clientlib[PATH_MAX] = {0};
+const os_char *gameinfo_clientlib = _gameinfo_clientlib;
+static os_char _gameinfo_serverlib[PATH_MAX] = {0};
+const os_char *gameinfo_serverlib = _gameinfo_serverlib;
+
+// magical argc/argv grabber so we don't have to go through procfs
+#ifdef __linux__
+static const char *prog_argv;
+static int storeargs(int argc, char *argv[]) {
+	prog_argv = argv;
+	return 0;
+}
+__attribute__((used, section(".init_array")))
+static void *pstoreargs = &storeargs;
+#endif
+
+// case insensitive substring match, expects s2 to be lowercase already!
+// note: in theory this shouldn't need to be case sensitive, but I've seen mods
+// use both lowercase and TitleCase so this is just to be as lenient as possible
+static bool matchtok(const char *s1, const char *s2, usize sz) {
+	for (; sz; --sz, ++s1, ++s2) if (tolower(*s1) != *s2) return false;
+	return true;
+}
+
+static void try_gamelib(const os_char *path, os_char *outpath) {
+	// _technically_ this is toctou, but I don't think that matters here
+	if (os_access(path, F_OK) != -1) {
+		os_strcpy(outpath, path);
+	}
+	else if (errno != ENOENT) {
+		con_warn("gameinfo: failed to access %" fS ": %s\n", path,
+				strerror(errno));
+	}
+}
+
+// note: p and len are a non-null-terminated string
+static inline void do_gamelib_search(const char *p, uint len, bool isgamebin) {
+	// sanity check: don't do a bunch of work for no reason
+	if (len >= PATH_MAX - 1 - (sizeof("client" OS_DLSUFFIX) - 1)) goto toobig;
+	os_char bindir[PATH_MAX];
+	os_char *outp = bindir;
+	// this should really be an snprintf, meh whatever
+	os_strcpy(bindir, exedir);
+	outp = bindir + os_strlen(bindir);
+	// quick note about windows encoding conversion: this MIGHT clobber the
+	// encoding of non-ascii mod names, but it's unclear if/how source handles
+	// that anyway, so we just have to assume there *are no* non-ascii mod
+	// names, since they'd also be clobbered, probably. if I'm wrong this can
+	// just change later to an explicit charset conversion, so... it's kinda
+	// whatever, I guess
+	const os_char *fmt = isgamebin ?
+		OS_LIT("/%.*") Fs OS_LIT("/") :
+		OS_LIT("/%.*") Fs OS_LIT("/bin/");
+	int spaceleft = PATH_MAX;
+	if (len >= 25 && matchtok(p, "|all_source_engine_paths|", 25)) {
+		// this special path doesn't seem any different to normal,
+		// why is this a thing?
+		p += 25; len -= 25;
+	}
+	else if (len >= 15 && matchtok(p, "|gameinfo_path|", 15)) {
+		// search in the actual mod/game directory
+		p += 15; len -= 15;
+		int ret = os_snprintf(bindir, PATH_MAX, OS_LIT("%s"), gamedir);
+		outp = bindir + ret;
+		spaceleft -= ret;
+	}
+	else {
+#ifdef _WIN32
+		// sigh
+		char api_needs_null_term[PATH_MAX];
+		memcpy(api_needs_null_term, p, len * sizeof(*p));
+		api_needs_null_term[len] = L'\0';
+		if (!PathIsRelativeA(api_needs_null_term))
+#else
+		if (*p == "/") // so much easier :')
+#endif
+	{
+		// the mod path is absolute, so we're not sticking anything else in
+		// front of it, so skip the leading slash in fmt and point the pointer
+		// at the start of the buffer
+		++fmt;
+		outp = bindir;
+	}}
+
+	// leave room for server/client.dll/so (note: server and client happen to
+	// conveniently have the same number of letters)
+	int fmtspace = spaceleft - (sizeof("client" OS_DLSUFFIX) - 1);
+	int ret = os_snprintf(outp, fmtspace, fmt, len, p);
+	if (ret >= fmtspace) {
+toobig: con_warn("gameinfo: skipping an overly long search path\n");
+		return;
+	}
+	outp += ret;
+	if (!*gameinfo_clientlib) {
+		os_strcpy(outp, OS_LIT("client" OS_DLSUFFIX));
+		try_gamelib(bindir, _gameinfo_clientlib);
+	}
+	if (!*gameinfo_serverlib) {
+		os_strcpy(outp, OS_LIT("server" OS_DLSUFFIX));
+		try_gamelib(bindir, _gameinfo_serverlib);
+	}
+}
+
+// state for the callback below to keep it somewhat reentrant-ish (except where
+// it isn't because I got lazy and wrote some spaghetti)
+struct kv_parsestate {
+	// after parsing a key we *don't* care about, how many nested subkeys have
+	// we come across?
+	short dontcarelvl;
+	// after parsing a key we *do* care about, which key in the matchkeys[]
+	// array below are we looking for next?
+	schar nestlvl;
+	// what kind of key did we just match?
+	schar matchtype;
+};
+
+// this is a sprawling mess. Too Bad!
+static void kv_cb(enum kv_token type, const char *p, uint len, void *_ctxt) {
+	struct kv_parsestate *ctxt = _ctxt;
+
+	static const struct {
+		const char *s;
+		uint len;
+	} matchkeys[] = {
+		{"gameinfo", 8},
+		{"filesystem", 10},
+		{"searchpaths", 11}
+	};
+
+	// values for ctxt->matchtype
+	enum {
+		mt_none,
+		mt_title,
+		mt_nest,
+		mt_game,
+		mt_gamebin
+	};
+
+	#define MATCH(s) (len == sizeof(s) - 1 && matchtok(p, s, sizeof(s) - 1))
+	switch (type) {
+		case KV_IDENT: case KV_IDENT_QUOTED:
+			if (ctxt->nestlvl == 1 && MATCH("game")) {
+				ctxt->matchtype = mt_title;
+			}
+			else if (ctxt->nestlvl == 3) {
+				// for some reason there's a million different ways of
+				// specifying the same type of path
+				if (MATCH("mod+game") || MATCH("game+mod") || MATCH("game") ||
+						MATCH("mod")) {
+					ctxt->matchtype = mt_game;
+				}
+				else if (MATCH("gamebin")) {
+					ctxt->matchtype = mt_gamebin;
+				}
+			}
+			else if (len == matchkeys[ctxt->nestlvl].len &&
+					matchtok(p, matchkeys[ctxt->nestlvl].s, len)) {
+				ctxt->matchtype = mt_nest;
+			}
+			break;
+		case KV_NEST_START:
+			if (ctxt->matchtype == mt_nest) ++ctxt->nestlvl;
+			else ++ctxt->dontcarelvl;
+			ctxt->matchtype = mt_none;
+			break;
+		case KV_VAL: case KV_VAL_QUOTED:
+			if (ctxt->dontcarelvl) break;
+			if (ctxt->matchtype == mt_title) {
+				// title really shouldn't get this long, but truncate just to
+				// avoid any trouble...
+				// also note: leaving 1 byte of space for null termination (the
+				// buffer is already zeroed initially)
+				if (len > sizeof(_gameinfo_title) - 1) {
+					len = sizeof(_gameinfo_title) - 1;
+				}
+				memcpy(_gameinfo_title, p, len);
+			}
+			else if (ctxt->matchtype == mt_game ||
+					ctxt->matchtype == mt_gamebin) {
+				// if we already have everything, we can just stop!
+				if (*gameinfo_clientlib && *gameinfo_serverlib) break;
+				do_gamelib_search(p, len, ctxt->matchtype == mt_gamebin);
+			}
+			ctxt->matchtype = mt_none;
+			break;
+		case KV_NEST_END:
+			if (ctxt->dontcarelvl) --ctxt->dontcarelvl; else --ctxt->nestlvl;
+	}
+	#undef MATCH
+}
+
+bool gameinfo_init(void) {
+	const os_char *modname = OS_LIT("hl2");
+#ifdef _WIN32
+	int len = GetModuleFileNameW(0, exedir, PATH_MAX);
+	if (!len) {
+		char err[128];
+		OS_WINDOWS_ERROR(err);
+		con_warn("gameinfo: couldn't get EXE path: %s\n", err);
+		return false;
+	}
+	// if the buffer is full and has no null, it's truncated
+	if (len == PATH_MAX && exedir[len - 1] != L'\0') {
+		con_warn("gameinfo: EXE path is too long!\n");
+		return false;
+	}
+#else
+	int len = readlink("/proc/self/exe", exedir, PATH_MAX);
+	if (len == -1) {
+		con_warn("gameinfo: couldn't get program path: %s\n", strerror(errno));
+		return false;
+	}
+	// if the buffer is full at all, it's truncated (readlink never writes \0)
+	if (len == PATH_MAX) {
+		con_warn("gameinfo: program path is too long!\n");
+		return false;
+	}
+	else {
+		exedir[len] = '\0';
+	}
+#endif
+	// find the last slash
+	os_char *p;
+	for (p = exedir + len - 1; *p != OS_LIT('/')
+#ifdef _WIN32
+			&& *p != L'\\'
+#endif
+	;		--p);
+	// ... and split on it
+	*p = 0;
+	const os_char *exename = p + 1;
+#ifdef _WIN32
+	// try and infer the default mod name (when -game isn't given) from the exe
+	// name for a few known games
+	if (!_wcsicmp(exename, L"left4dead2.exe")) modname = L"left4dead2";
+	else if (!_wcsicmp(exename, L"left4dead.exe")) modname = L"left4dead";
+	else if (!_wcsicmp(exename, L"portal2.exe")) modname = L"portal2";
+
+	const ushort *args = GetCommandLineW();
+	const ushort *argp = args;
+	ushort modbuf[PATH_MAX];
+	// have to take the _last_ occurence of -game because sourcemods get the
+	// flag twice, for some reason
+	while (argp = wcsstr(argp, L" -game ")) {
+		argp += 7;
+		while (*argp == L' ') ++argp;
+		ushort sep = L' ';
+		// WARNING: not handling escaped quotes and such nonsense, since you
+		// can't have quotes in filepaths anyway outside of UNC and I'm just
+		// assuming there's no way Source could even be started with such an
+		// insanely named mod. We'll see how this assumption holds up!
+		if (*argp == L'"') {
+			++argp;
+			sep = L'"';
+		}
+		ushort *bufp = modbuf;
+		for (; *argp != L'\0' && *argp != sep; ++argp, ++bufp) {
+			if (bufp - modbuf == PATH_MAX - 1) {
+				con_warn("gameinfo: mod name parameter is too long\n");
+				return false;
+			}
+			*bufp = *argp;
+		}
+		*bufp = L'\0';
+		modname = modbuf;
+	}
+	bool isrelative = PathIsRelativeW(modname);
+#else
+	// also do the executable name check just for portal2_linux
+	if (!strcmp(exename, "portal2_linux")) modname = "portal2";
+	// ah, the sane, straightforward world of unix command line arguments :)
+	for (char **pp = prog_argv + 1; *pp; ++pp) {
+		if (!strcmp(*pp, "-game")) {
+			if (!*++pp) break;
+			modname = *pp;
+		}
+	}
+	// ah, the sane, straightforward world of unix paths :)
+	bool isrelative = modname[0] != '/';
+#endif
+
+	int ret = isrelative ?
+		os_snprintf(gamedir, PATH_MAX, OS_LIT("%s/%s"), exedir, modname) :
+		// mod name might actually be an absolute (if installed in steam
+		// sourcemods for example)
+		os_snprintf(gamedir, PATH_MAX, OS_LIT("%s"), modname);
+	if (ret >= PATH_MAX) {
+		con_warn("gameinfo: game directory path is too long!\n");
+		return false;
+	}
+	os_char gameinfopath[PATH_MAX];
+	if (os_snprintf(gameinfopath, PATH_MAX, OS_LIT("%s/gameinfo.txt"),
+			gamedir, modname) >= PATH_MAX) {
+		con_warn("gameinfo: gameinfo.text path is too long!\n");
+		return false;
+	}
+
+	int fd = os_open(gameinfopath, O_RDONLY);
+	if (fd == -1) {
+		con_warn("gameinfo: couldn't open gameinfo.txt: %s\n", strerror(errno));
+		return false;
+	}
+	char buf[1024];
+	struct kv_parser kvp = {0};
+	struct kv_parsestate ctxt = {0};
+	int nread;
+	while (nread = read(fd, buf, sizeof(buf))) {
+		if (nread == -1) {
+			con_warn("gameinfo: couldn't read gameinfo.txt: %s\n",
+					strerror(errno));
+			goto e;
+		}
+		kv_parser_feed(&kvp, buf, nread, &kv_cb, &ctxt);
+		if (kvp.state == KV_PARSER_ERROR) goto ep;
+	}
+	kv_parser_done(&kvp);
+	if (kvp.state == KV_PARSER_ERROR) goto ep;
+
+	close(fd);
+	return true;
+
+ep:	con_warn("gameinfo: couldn't parse gameinfo.txt (%d:%d): %s\n",
+			kvp.line, kvp.col, kvp.errmsg);
+e:	close(fd);
+	return false;
+}
+
+// vi: sw=4 ts=4 noet tw=80 cc=80