Rework OS abstractions

- As much as possible avoid dragging system headers into translation
  units. This should avoid namespace pollution and, hopefully, speed up
  builds a little bit.

- Avoid leaning on the UCRT so much on Windows - prefer native win32
  calls and native file handles except where doing so is inconvenient
  (in particular, for stat(), which we might try and replace later).

- Also, switch from SystemFunction036 to ProcessPrng on Windows. This
  requires us to generate a stub for bcryptprimitives.dll because
  Microsoft haven't bothered to provide a link library, but the function
  is better-documented and seems to be a more direct under-the-hood call
  as well. Apparently it's what's used by the major web browsers these
  days, which seems like a good indication it's stable and trusted.

- Lastly, remove a bunch of functions and macros and stuff that weren't
  actually being used. It seems good to try and keep the scope of
  OS-dependent stuff relatively contained and only add to it when
  actually required.

21 files changed, 585 insertions, 371 deletions

diff --git a/compile b/compile
index bcda4ec..d9ab4f6 100755
--- a/compile
+++ b/compile
@@ -78,6 +78,7 @@ src="\
 	l4dreset.c
 	l4dwarp.c
 	nosleep.c
+	os.c
 	portalcolours.c
 	sst.c
 	xhair.c
diff --git a/compile.bat b/compile.bat
index a50dbb0..215fc32 100644
--- a/compile.bat
+++ b/compile.bat
@@ -13,6 +13,13 @@ if not exist .build\include\ md .build\include
 if "%CC%"=="" set CC=clang --target=i686-pc-windows-msvc

 if "%HOSTCC%"=="" set HOSTCC=clang

 

+set host64=0

+(

+	echo:#ifndef _WIN64

+	echo:#error

+	echo:#endif

+) | %HOSTCC% -E - >nul 2>nul && set host64=1

+

 set warnings=-Wall -pedantic -Wno-parentheses -Wno-missing-braces ^

 -Wno-gnu-zero-variadic-macro-arguments -Werror=implicit-function-declaration ^

 -Werror=vla

@@ -86,6 +93,7 @@ setlocal DisableDelayedExpansion
 :+ l4dwarp.c

 :+ nomute.c

 :+ nosleep.c

+:+ os.c

 :+ portalcolours.c

 :+ rinput.c

 :+ sst.c

@@ -96,19 +104,27 @@ if "%dbg%"=="1" set src=%src% src/dbg.c
 if "%dbg%"=="1" set src=%src% src/udis86.c

 if "%dbg%"=="0" set src=%src% src/wincrt.c

 

-%HOSTCC% -fuse-ld=lld -municode -O2 %warnings% -D_CRT_SECURE_NO_WARNINGS -include stdbool.h -ladvapi32 ^

--o .build/codegen.exe src/build/codegen.c src/build/cmeta.c || exit /b

+%CC% -fuse-ld=lld -shared -O0 -w -o .build/bcryptprimitives.dll -Wl,-def:src/stubs/bcryptprimitives.def src/stubs/bcryptprimitives.c

+set lbcryptprimitives_host=-lbcryptprimitives

+if %host64%==1 (

+	:: note: no mangling madness on x64, so we can just call the linker directly

+	lld-link -machine:x64 -def:src/stubs/bcryptprimitives.def -implib:.build/bcryptprimitives64.lib

+	set lbcryptprimitives_host=-lbcryptprimitives64

+)

+%CC% -fuse-ld=lld -shared -O0 -w -o .build/tier0.dll src/stubs/tier0.c

+%CC% -fuse-ld=lld -shared -O0 -w -o .build/vstdlib.dll src/stubs/vstdlib.c

+

 %HOSTCC% -fuse-ld=lld -municode -O2 %warnings% -D_CRT_SECURE_NO_WARNINGS -include stdbool.h ^

--o .build/mkgamedata.exe src/build/mkgamedata.c src/kv.c || exit /b

-%HOSTCC% -fuse-ld=lld -municode -O2 %warnings% -D_CRT_SECURE_NO_WARNINGS -include stdbool.h -ladvapi32 ^

--o .build/mkentprops.exe src/build/mkentprops.c src/kv.c || exit /b

-.build\codegen.exe%src% || exit /b

+-L.build %lbcryptprimitives_host% -o .build/codegen.exe src/build/codegen.c src/build/cmeta.c src/os.c || exit /b

+%HOSTCC% -fuse-ld=lld -municode -O2 %warnings% -D_CRT_SECURE_NO_WARNINGS -include stdbool.h ^

+-L.build %lbcryptprimitives_host% -o .build/mkgamedata.exe src/build/mkgamedata.c src/kv.c src/os.c || exit /b

+%HOSTCC% -fuse-ld=lld -municode -O2 %warnings% -D_CRT_SECURE_NO_WARNINGS -include stdbool.h ^

+-L.build %lbcryptprimitives_host% -o .build/mkentprops.exe src/build/mkentprops.c src/kv.c src/os.c || exit /b

+.build\codegen.exe%src% || goto :end

 .build\mkgamedata.exe gamedata/engine.kv gamedata/gamelib.kv gamedata/inputsystem.kv ^

 gamedata/matchmaking.kv gamedata/vgui2.kv gamedata/vguimatsurface.kv || exit /b

 .build\mkentprops.exe gamedata/entprops.kv || exit /b

 llvm-rc /FO .build\dll.res src\dll.rc || exit /b

-%CC% -fuse-ld=lld -shared -O0 -w -o .build/tier0.dll src/stubs/tier0.c

-%CC% -fuse-ld=lld -shared -O0 -w -o .build/vstdlib.dll src/stubs/vstdlib.c

 for %%b in (%src%) do ( call :cc %%b || exit /b )

 :: we need different library names for debugging because Microsoft...

 :: actually, it's different anyway because we don't use vcruntime for releases

@@ -119,7 +135,7 @@ if "%dbg%"=="1" (
 	set clibs=-lucrt

 )

 %CC% -fuse-ld=lld -shared -flto %ldflags% -Wl,/IMPLIB:.build/sst.lib,/Brepro,/nodefaultlib ^

--L.build %clibs% -lkernel32 -luser32 -ladvapi32 -lshlwapi -ld3d9 -ldsound ^

+-L.build %clibs% -lkernel32 -luser32 -lbcryptprimitives -lshlwapi -ld3d9 -ldsound ^

 -ltier0 -lvstdlib -lntdll -o sst.dll%objs% .build/dll.res || exit /b

 :: get rid of another useless file (can we just not create this???)

 del .build\sst.lib

@@ -127,7 +143,7 @@ del .build\sst.lib
 %HOSTCC% -fuse-ld=lld -O2 -g -include test/test.h -o .build/bitbuf.test.exe test/bitbuf.test.c || exit /b

 .build\bitbuf.test.exe || exit /b

 :: special case: test must be 32-bit

-%HOSTCC% -fuse-ld=lld -m32 -O2 -g -ladvapi32 -include test/test.h -o .build/hook.test.exe test/hook.test.c || exit /b

+%HOSTCC% -fuse-ld=lld -m32 -O2 -g -L.build -lbcryptprimitives -include test/test.h -o .build/hook.test.exe test/hook.test.c || exit /b

 .build\hook.test.exe || exit /b

 %HOSTCC% -fuse-ld=lld -O2 -g -include test/test.h -o .build/kv.test.exe test/kv.test.c || exit /b

 .build\kv.test.exe || exit /b

diff --git a/src/3p/chibicc/tokenize.c b/src/3p/chibicc/tokenize.c
index b13edd5..6738206 100644
--- a/src/3p/chibicc/tokenize.c
+++ b/src/3p/chibicc/tokenize.c
@@ -1,5 +1,9 @@
 #include "chibicc.h"
 
+#ifdef _WIN32
+#define strncasecmp _strnicmp
+#endif
+
 // Input file
 static File *current_file;
 
diff --git a/src/ac.c b/src/ac.c
index 8b163b9..8c98cfb 100644
--- a/src/ac.c
+++ b/src/ac.c
@@ -17,6 +17,13 @@
 
 #include <stdlib.h>
 
+#ifdef _WIN32
+#include <Windows.h>
+#include <werapi.h>
+#else
+#include <sys/mman.h>
+#endif
+
 #include "alias.h"
 #include "bind.h"
 #include "chunklets/fastspin.h"
@@ -41,10 +48,6 @@
 #include "x86.h"
 #include "x86util.h"
 
-#ifdef _WIN32
-#include <werapi.h> // must be after Windows.h (via os.h)
-#endif
-
 FEATURE()
 REQUIRE(bind)
 REQUIRE(democustom)
diff --git a/src/build/cmeta.c b/src/build/cmeta.c
index 0c9b3ca..8a2416d 100644
--- a/src/build/cmeta.c
+++ b/src/build/cmeta.c
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2023 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2024 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
@@ -102,15 +102,15 @@ static void die(const char *s) {
 	exit(100);
 }
 
-static char *readsource(const os_char *f) {
-	int fd = os_open(f, O_RDONLY);
-	if (fd == -1) return 0;
+static char *readsource(const os_char *path) {
+	int f = os_open_read(path);
+	if (f == -1) return 0;
 	uint bufsz = 8192;
 	char *buf = malloc(bufsz);
 	if (!buf) die("couldn't allocate memory");
 	int nread;
 	int off = 0;
-	while ((nread = read(fd, buf + off, bufsz - off)) > 0) {
+	while ((nread = os_read(f, buf + off, bufsz - off)) > 0) {
 		off += nread;
 		if (off == bufsz) {
 			bufsz *= 2;
@@ -122,24 +122,24 @@ static char *readsource(const os_char *f) {
 	}
 	if (nread == -1) die("couldn't read file");
 	buf[off] = 0;
-	close(fd);
+	os_close(f);
 	return buf;
 }
 
 // as per cmeta.h this is totally opaque; it's actually just a Token in disguise
 struct cmeta;
 
-const struct cmeta *cmeta_loadfile(const os_char *f) {
-	char *buf = readsource(f);
+const struct cmeta *cmeta_loadfile(const os_char *path) {
+	char *buf = readsource(path);
 	if (!buf) return 0;
 #ifdef _WIN32
-	char *realname = malloc(wcslen(f) + 1);
+	char *realname = malloc(wcslen(path) + 1);
 	if (!realname) die("couldn't allocate memory");
 	// XXX: being lazy about Unicode right now; a general purpose tool should
 	// implement WTF8 or something. SST itself doesn't have any unicode paths
 	// though, so don't really care as much.
-	*realname = *f;
-	for (const ushort *p = f + 1; p[-1]; ++p) realname[p - f] = *p;
+	*realname = *path;
+	for (const ushort *p = path + 1; p[-1]; ++p) realname[p - path] = *p;
 #else
 	const char *realname = f;
 #endif
diff --git a/src/build/cmeta.h b/src/build/cmeta.h
index 48a2d6d..86ae0ec 100644
--- a/src/build/cmeta.h
+++ b/src/build/cmeta.h
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2022 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2024 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
@@ -21,7 +21,7 @@
 
 struct cmeta;
 
-const struct cmeta *cmeta_loadfile(const os_char *f);
+const struct cmeta *cmeta_loadfile(const os_char *path);
 
 /*
  * Iterates through all the #include directives in a file, passing each one in
diff --git a/src/build/mkentprops.c b/src/build/mkentprops.c
index 0781f25..2043a9b 100644
--- a/src/build/mkentprops.c
+++ b/src/build/mkentprops.c
@@ -174,13 +174,13 @@ _( "}")
 
 int OS_MAIN(int argc, os_char *argv[]) {
 	for (++argv; *argv; ++argv) {
-		int fd = os_open(*argv, O_RDONLY);
-		if (fd == -1) die("couldn't open file");
+		int f = os_open_read(*argv);
+		if (f == -1) die("couldn't open file");
 		struct kv_parser kv = {0};
 		struct parsestate state = {*argv, &kv};
 		char buf[1024];
 		int nread;
-		while (nread = read(fd, buf, sizeof(buf))) {
+		while (nread = os_read(f, buf, sizeof(buf))) {
 			if (nread == -1) die("couldn't read file");
 			if (!kv_parser_feed(&kv, buf, nread, &kv_cb, &state)) goto ep;
 		}
@@ -189,7 +189,7 @@ ep:			fprintf(stderr, "mkentprops: %" fS ":%d:%d: bad syntax: %s\n",
 					*argv, kv.line, kv.col, kv.errmsg);
 			exit(1);
 		}
-		close(fd);
+		os_close(f);
 	}
 
 	FILE *out = fopen(".build/include/entprops.gen.h", "wb");
diff --git a/src/build/mkgamedata.c b/src/build/mkgamedata.c
index d49eef5..bf359b2 100644
--- a/src/build/mkgamedata.c
+++ b/src/build/mkgamedata.c
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2022 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2024 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
@@ -211,13 +211,13 @@ _( "}")
 
 int OS_MAIN(int argc, os_char *argv[]) {
 	for (++argv; *argv; ++argv) {
-		int fd = os_open(*argv, O_RDONLY);
+		int fd = os_open_read(*argv);
 		if (fd == -1) die("couldn't open file");
 		struct kv_parser kv = {0};
 		struct parsestate state = {*argv, &kv, &root};
 		char buf[1024];
 		int nread;
-		while (nread = read(fd, buf, sizeof(buf))) {
+		while (nread = os_read(fd, buf, sizeof(buf))) {
 			if (nread == -1) die("couldn't read file");
 			if (!kv_parser_feed(&kv, buf, nread, &kv_cb, &state)) goto ep;
 		}
@@ -226,7 +226,7 @@ ep:			fprintf(stderr, "mkgamedata: %" fS ":%d:%d: bad syntax: %s\n",
 					*argv, kv.line, kv.col, kv.errmsg);
 			exit(1);
 		}
-		close(fd);
+		os_close(fd);
 	}
 
 	FILE *out = fopen(".build/include/gamedata.gen.h", "wb");
diff --git a/src/build/skiplist.h b/src/build/skiplist.h
index b747d89..ab6a920 100644
--- a/src/build/skiplist.h
+++ b/src/build/skiplist.h
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2022 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2024 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
@@ -24,6 +24,7 @@
 
 #ifdef _WIN32
 static inline int _skiplist_ffs(uint x) {
+	uchar _BitScanForward(ulong *idx, ulong mask);
 	uint ret;
 	// on Windows, sizeof(ulong) == sizeof(uint)
 	if (_BitScanForward((ulong *)&ret, x)) return ret + 1; else return 0;
diff --git a/src/errmsg.h b/src/errmsg.h
index 17a4457..cdf5095 100644
--- a/src/errmsg.h
+++ b/src/errmsg.h
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2022 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2024 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
@@ -17,6 +17,15 @@
 #ifndef INC_ERRMSG_H
 #define INC_ERRMSG_H
 
+#ifdef _WIN32
+#include <stdarg.h>
+
+// note: redundant declspec avoids warnings if Windows.h was also included
+__declspec(dllimport) unsigned long __stdcall FormatMessageA(unsigned long,
+		const void *, unsigned long, unsigned long, char *, unsigned long,
+		va_list *);
+#endif
+
 #include "con_.h"
 #include "os.h"
 
@@ -48,14 +57,17 @@ extern const char msg_note[], msg_warn[], msg_error[];
 
 #ifdef _WIN32
 #define _errmsg_sys(msg, ...) do { \
-	char _warnsys_buf[512]; \
-	OS_WINDOWS_ERROR(_warnsys_buf); \
-	_errmsg_msg(_ERRMSG_STR(MODULE_NAME), msg, __VA_ARGS__, _warnsys_buf); \
+	char _errmsg_buf[512]; \
+	FormatMessageA(/*FORMAT_MESSAGE_FROM_SYSTEM*/ 4096, 0, os_lasterror(), \
+			/*MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT)*/ 1024, _errmsg_buf, \
+			sizeof(_errmsg_buf), 0); \
+	_errmsg_msg(_ERRMSG_STR(MODULE_NAME), msg, __VA_ARGS__, _errmsg_buf); \
 } while (0)
 #define _errmsg_dl _errmsg_sys
 #else
 #define _errmsg_sys _errmsg_std
 static inline const char *_errmsg_dlerror(void) {
+	char *dlerror(void);
 	const char *e = dlerror();
 	if (!e) return "Unknown error"; // just in case, better avoid weirdness!
 	return e;
diff --git a/src/gameinfo.c b/src/gameinfo.c
index 85220a8..d535a44 100644
--- a/src/gameinfo.c
+++ b/src/gameinfo.c
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2023 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2024 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
@@ -15,6 +15,9 @@
  */
 
 #include <string.h>
+#ifdef _WIN32
+#include <Windows.h> // MultiByteToWideChar()
+#endif
 
 #include "engineapi.h"
 #include "errmsg.h"
diff --git a/src/hook.c b/src/hook.c
index 9a6e885..fe311cc 100644
--- a/src/hook.c
+++ b/src/hook.c
@@ -23,6 +23,13 @@
 #include "os.h"
 #include "x86.h"
 
+#ifdef _WIN32
+// try to avoid pulling in all of Windows.h for this... (redundant dllimport
+// avoids warnings in hook.test.c where Windows.h is included via test.h)
+__declspec(dllimport) int __stdcall FlushInstructionCache(
+		void *, const void *, usize);
+#endif
+
 // Warning: half-arsed hacky implementation (because that's all we really need)
 // Almost certainly breaks in some weird cases. Oh well! Most of the time,
 // vtable hooking is more reliable, this is only for, uh, emergencies.
diff --git a/src/nomute.c b/src/nomute.c
index 93cfcd2..6a42d46 100644
--- a/src/nomute.c
+++ b/src/nomute.c
@@ -1,6 +1,6 @@
 /*
  * Copyright © 2023 Willian Henrique <wsimanbrazil@yahoo.com.br>
- * Copyright © 2023 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2024 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
@@ -18,16 +18,17 @@
 // TODO(linux): this is currently only built on Windows, but a linux
 // implementation would be also useful for some games e.g. L4D2
 
+// NOTE: all three of these headers must be in this order. annoyingly.
+#include <Windows.h>
+#include <mmeapi.h>
+#include <dsound.h>
+
 #include "con_.h"
 #include "errmsg.h"
 #include "feature.h"
 #include "os.h"
 #include "sst.h"
 
-// these have to come after Windows.h (via os.h) and in this order
-#include <mmeapi.h>
-#include <dsound.h>
-
 FEATURE("inactive window audio control")
 
 DEF_CVAR_UNREG(snd_mute_losefocus,
diff --git a/src/os-unix.h b/src/os-unix.h
deleted file mode 100644
index 097d300..0000000
--- a/src/os-unix.h
+++ /dev/null
@@ -1,125 +0,0 @@
-/*
- * 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.
- */
-
-/* Unix-specific definitions for os.h - don't include this directly! */
-
-#ifdef __GNUC__
-#define EXPORT __attribute__((visibility("default")))
-#else
-#define EXPORT int novis[-!!"visibility attribute requires Clang or GCC"];
-#endif
-#define IMPORT
-
-typedef char os_char;
-#define OS_LIT(x) x
-#define os_snprintf snprintf
-#define os_strchr strchr
-#define os_strcmp strcmp
-#define os_strcpy strcpy
-#define os_strlen strlen
-#define os_fopen fopen
-#define os_open open
-#define os_access access
-#define os_stat stat
-#define os_mkdir(f) mkdir(f, 0755) // use real mkdir(2) if the mode matters
-#define os_unlink unlink
-#define os_getenv getenv
-#define os_getcwd getcwd
-
-#define OS_DLPREFIX "lib"
-#define OS_DLSUFFIX ".so"
-
-#define OS_MAIN main
-
-static inline void *os_dlopen(const char *name) {
-	return dlopen(name, RTLD_NOW);
-}
-#define os_dlsym dlsym
-
-#ifdef __linux__
-// note: this is glibc-specific. it shouldn't be used in build-time code, just
-// the plugin itself (that really shouldn't be a problem).
-
-// private struct hidden behind _GNU_SOURCE. see dlinfo(3) or <link.h>
-struct gnu_link_map {
-	unsigned long l_addr;
-	const char *l_name;
-	void *l_ld;
-	struct gnu_link_map *l_next, *l_prev;
-	// [more private stuff below]
-};
-
-static inline void *os_dlhandle(const char *name) {
-	extern struct gnu_link_map *_os_lmbase; // note: defined in sst.c for now
-	if (!_os_lmbase) { // IMPORTANT: not thread safe. don't forget later!
-		_os_lmbase = (struct gnu_link_map *)dlopen("libc.so.6",
-				RTLD_LAZY | RTLD_NOLOAD);
-		dlclose(_os_lmbase); // assume success
-		while (_os_lmbase->l_prev) _os_lmbase = _os_lmbase->l_prev;
-	}
-	// this is a tiny bit crude, but basically okay. we just want to find
-	// something that roughly matches the basename, rather than needing an exact
-	// path, in a manner vaguely similar to Windows' GetModuleHandle(). that way
-	// we can just look up client.so or something without having to figure out
-	// where exactly that is.
-	for (struct gnu_link_map *lm = _os_lmbase; lm; lm = lm->l_next) {
-		if (name[0] == '/') {
-			if (!strcmp(name, lm->l_name)) return lm;
-			continue;
-		}
-		int namelen = strlen(lm->l_name);
-		int sublen = strlen(name);
-		if (sublen >= namelen) continue;
-		if (lm->l_name[namelen - sublen - 1] == '/' && !memcmp(
-				lm->l_name + namelen - sublen, name, sublen)) {
-			return lm;
-		}
-	}
-	return 0;
-}
-
-static inline int os_dlfile(void *m, char *buf, int sz) {
-	struct gnu_link_map *lm = m;
-	int ssz = strlen(lm->l_name) + 1;
-	if (ssz > sz) { errno = ENAMETOOLONG; return -1; }
-	memcpy(buf, lm->l_name, ssz);
-	return ssz;
-}
-
-#endif
-
-// unix mprot flags are much nicer but cannot be defined in terms of the windows
-// ones, so we use the windows ones and define them in terms of the unix ones.
-// another victory for stupid!
-#define PAGE_NOACCESS			0
-#define PAGE_READONLY			PROT_READ
-#define PAGE_READWRITE			PROT_READ | PROT_WRITE
-#define PAGE_EXECUTE_READ		PROT_READ |              PROT_EXEC
-#define PAGE_EXECUTE_READWRITE	PROT_READ | PROT_WRITE | PROT_EXEC
-
-static inline bool os_mprot(void *addr, int len, int fl) {
-	// round down address and round up size
-	addr = (void *)((unsigned long)addr & ~(4095));
-	len = len + 4095 & ~(4095);
-	return mprotect(addr, len, fl) != -1;
-}
-
-static inline void os_randombytes(void *buf, int sz) {
-	// if this call fails, the system is doomed, so loop until success and pray.
-	while (getentropy(buf, sz) == -1);
-}
-
-// vi: sw=4 ts=4 noet tw=80 cc=80
diff --git a/src/os-win32.h b/src/os-win32.h
deleted file mode 100644
index db20964..0000000
--- a/src/os-win32.h
+++ /dev/null
@@ -1,131 +0,0 @@
-/*
- * 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.
- */
-
-/* Windows-specific definitions for os.h - don't include this directly! */
-
-#define IMPORT __declspec(dllimport) // only needed for variables
-#define EXPORT __declspec(dllexport)
-
-typedef unsigned short os_char;
-#define _OS_CAT(L, x) L##x
-#define OS_LIT(x) _OS_CAT(L, x)
-
-#define os_snprintf _snwprintf
-#define os_strchr wcschr
-#define os_strcmp wcscmp
-#define os_strcpy wcscpy
-#define os_strlen wcslen
-#define strncasecmp _strnicmp // stupid!
-
-#define os_fopen _wfopen
-// yuck :(
-#define _os_open3(path, flags, mode) _wopen((path), (flags) | _O_BINARY, (mode))
-#define _os_open2(path, flags) _wopen((path), (flags) | _O_BINARY)
-#define _os_open(a, b, c, x, ...) x
-#define os_open(...) _os_open(__VA_ARGS__, _os_open3, _os_open2, _)(__VA_ARGS__)
-#define os_access _waccess
-// ucrt defines __stat64 to _stat64. we want _wstat64 to be the actual function
-#define _stat64(path, buf) _wstat64(path, buf)
-#define os_stat _stat64
-#define os_mkdir _wmkdir
-#define os_unlink _wunlink
-#define os_getenv _wgetenv
-#define os_getcwd _wgetcwd
-
-#define OS_DLPREFIX ""
-#define OS_DLSUFFIX ".dll"
-
-#define OS_MAIN wmain
-
-static inline void *os_dlopen(const unsigned short *name) {
-	return LoadLibraryW(name);
-}
-static inline void *os_dlhandle(const unsigned short *name) {
-	return GetModuleHandleW(name);
-}
-static inline void *os_dlsym(void *m, const char *s) {
-	return (void *)GetProcAddress(m, s);
-}
-
-static inline int os_dlfile(void *m, unsigned short *buf, int sz) {
-	unsigned int n = GetModuleFileNameW(m, buf, sz);
-	if (n == 0 || n == sz) return -1;
-	// get the canonical capitalisation, as for some reason GetModuleFileName()
-	// returns all lowercase. this doesn't really matter except it looks nicer
-	GetLongPathNameW(buf, buf, n + 1);
-	// the drive letter will also be lower case, if it is an actual drive letter
-	// of course. it should be; I'm not gonna lose sleep over UNC paths and such
-	if (buf[0] >= L'a' && buf[0] <= L'z' && buf[1] == L':') buf[0] &= ~32u;
-	return n;
-}
-
-static inline bool os_mprot(void *addr, int len, int fl) {
-	unsigned long old;
-	return !!VirtualProtect(addr, len, fl, &old);
-}
-
-// SystemFunction036 is the *real* name of "RtlGenRandom," and is also
-// incorrectly defined in system headers. Yay.
-int __stdcall SystemFunction036(void *buf, unsigned long sz);
-
-static inline void os_randombytes(void *buf, int sz) {
-	// if this call fails, the system is doomed, so loop until success and pray.
-	while (!SystemFunction036(buf, sz));
-}
-
-/* Further Windows-specific workarounds because Windows is great */
-
-#ifndef PATH_MAX
-// XXX: win32/crt has this dumb 260 limit even though the actual kernel imposes
-// no limit (though apparently NTFS has a limit of 65535). Theoretically we
-// could do some memes with UNC paths to extend it to at least have parity with
-// Unix PATH_MAX (4096), but for now we just kind of accept that Windows is a
-// disaster.
-#define PATH_MAX MAX_PATH
-#endif
-
-// why does Windows prefix so many things with underscores?
-#define alloca _alloca
-#define read _read
-#define write _write
-#define close _close
-#define fdopen _fdopen
-#define dup _dup
-#define dup2 _dup2
-#define strdup _strdup
-#define fstat _fstat64
-#define lseek _lseeki64
-#define O_RDONLY _O_RDONLY
-#define O_RDWR _O_RDWR
-#define O_CLOEXEC _O_NOINHERIT // and why did they rename this!?
-#define O_CREAT _O_CREAT
-#define O_EXCL _O_EXCL
-// missing access() flags
-#define F_OK 0
-#define R_OK 4
-#define W_OK 2
-#define X_OK R_OK // there's no actual X bit, just pretend
-
-// windows doesn't define this for some reason!? note: add others as needed...
-#define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
-
-// just dump this boilerplate here as well, I spose
-#define OS_WINDOWS_ERROR(arrayname) \
-	FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, 0, GetLastError(), \
-			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), arrayname, \
-			sizeof(arrayname), 0)
-
-// vi: sw=4 ts=4 noet tw=80 cc=80
diff --git a/src/os.c b/src/os.c
new file mode 100644
index 0000000..49cab63
--- /dev/null
+++ b/src/os.c
@@ -0,0 +1,204 @@
+/*
+ * Copyright © 2024 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 <fcntl.h>
+#include <stdlib.h>
+#ifdef _WIN32
+#include <Windows.h>
+#else
+#include <errno.h>
+#include <dlfcn.h>
+#include <limits.h>
+#include <link.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#endif
+
+#include "intdefs.h"
+
+#ifdef _WIN32
+
+int os_lasterror(void) { return GetLastError(); }
+
+// N.B. file handle values are 32-bit, even in 64-bit builds. I'm not crazy!
+
+int os_open_read(const ushort *path) {
+	return (int)(ssize)CreateFileW(path, GENERIC_READ,
+			FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING,
+			FILE_ATTRIBUTE_NORMAL, 0);
+}
+int os_open_write(const ushort *file) {
+	return (int)(ssize)CreateFileW(file, GENERIC_READ | GENERIC_WRITE,
+			FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_ALWAYS,
+			FILE_ATTRIBUTE_NORMAL, 0);
+}
+int os_open_writetrunc(const ushort *file) {
+	return (int)(ssize)CreateFileW(file, GENERIC_READ | GENERIC_WRITE,
+			FILE_SHARE_READ | FILE_SHARE_WRITE, 0, CREATE_ALWAYS,
+			FILE_ATTRIBUTE_NORMAL, 0);
+}
+
+int os_read(int f, void *buf, int max) {
+	ulong n;
+	return ReadFile((void *)(ssize)f, buf, max, &n, 0) ? n : -1;
+}
+int os_write(int f, const void *buf, int len) {
+	ulong n;
+	return WriteFile((void *)(ssize)f, buf, len, &n, 0) ? n : -1;
+}
+
+vlong os_fsize(int f) {
+	vlong ret;
+	if (!GetFileSizeEx((void *)(ssize)f, (LARGE_INTEGER *)&ret)) return -1;
+	return ret;
+}
+
+void os_close(int f) {
+	CloseHandle((void *)(ssize)f);
+}
+
+void os_getcwd(ushort buf[static 260]) { GetCurrentDirectoryW(260, buf); }
+
+bool os_mkdir(const ushort *path) { return CreateDirectoryW(path, 0); }
+bool os_unlink(const ushort *path) { return DeleteFileW(path); }
+bool os_rmdir(const ushort *path) { return RemoveDirectoryW(path); }
+
+int __stdcall ProcessPrng(char *data, usize sz); // from bcryptprimitives.dll
+void os_randombytes(void *buf, int sz) { ProcessPrng(buf, sz); }
+
+void *os_dlhandle(const ushort *name) {
+	return GetModuleHandleW(name);
+}
+void *os_dlsym(void *restrict lib, const char *restrict s) {
+	return (void *)GetProcAddress(lib, s);
+}
+int os_dlfile(void *lib, ushort *buf, int sz) {
+	unsigned int n = GetModuleFileNameW(lib, buf, sz);
+	if (n == 0 || n == sz) return -1;
+	// get the canonical capitalisation, as for some reason GetModuleFileName()
+	// returns all lowercase. this doesn't really matter except it looks nicer
+	GetLongPathNameW(buf, buf, n + 1);
+	// the drive letter will also be lower case, if it is an actual drive letter
+	// of course. it should be; I'm not gonna lose sleep over UNC paths and such
+	if (buf[0] >= L'a' && buf[0] <= L'z' && buf[1] == L':') buf[0] &= ~32u;
+	return n;
+}
+
+bool os_mprot(void *addr, int len, int mode) {
+	ulong old;
+	return !!VirtualProtect(addr, len, mode, &old);
+}
+
+#else
+
+int os_lasterror(void) { return errno; }
+
+int os_open_read(const char *path) {
+	return open(path, O_RDONLY | O_CLOEXEC);
+}
+int os_open_write(const char *path) {
+	return open(path, O_RDWR | O_CLOEXEC | O_CREAT, 0644);
+}
+int os_open_writetrunc(const char *path) {
+	return open(path, O_RDWR | O_CLOEXEC | O_CREAT | O_TRUNC, 0644);
+}
+int os_read(int f, void *buf, int max) { return read(f, buf, max); }
+int os_write(int f, const void *buf, int max) { return write(f, buf, max); }
+void os_close(int f) { close(f); }
+
+vlong os_fsize(int f) {
+	struct stat s;
+	if (stat(f, &s) == -1) return -1;
+	return s.st_size;
+}
+
+void os_getcwd(char buf[PATH_MAX]) { getcwd(buf, PATH_MAX); }
+
+bool os_mkdir(const char *path) { return mkdir(path, 0555) != -1; }
+bool os_unlink(const char *path) { return unlink(path) != -1; }
+bool os_rmdir(const char *path) { return rmdir(path) != -1; }
+
+void *os_dlsym(void *restrict lib, const char *restrict name) {
+	return dlsym(lib, name);
+}
+
+bool os_mprot(void *addr, int len, int mode) {
+	// round down address and round up size
+	addr = (void *)((ulong)addr & ~(4095));
+	len = len + 4095 & ~(4095);
+	return mprotect(addr, len, mode) != -1;
+}
+
+void os_randombytes(void *buf, int sz) { while (getentropy(buf, sz) == -1); }
+
+#endif
+
+#ifdef __linux__
+// glibc-specific stuff here. it shouldn't be used in build-time code, just
+// the plugin itself (that really shouldn't be a problem).
+
+// private struct hidden behind _GNU_SOURCE. see dlinfo(3) or <link.h>
+struct link_map {
+	ulong l_addr;
+	const char *l_name;
+	void *l_ld;
+	struct link_map *l_next, *l_prev;
+	// [more private stuff below]
+};
+
+static struct link_map *lmbase = 0;
+
+void *os_dlhandle(const char *name) {
+	extern struct link_map *lmbase; // note: defined in sst.c for now
+	if (!lmbase) { // IMPORTANT: not thread safe. don't forget later!
+		lmbase = (struct link_map *)dlopen("libc.so.6", RTLD_LAZY | RTLD_NOLOAD);
+		dlclose(lmbase); // assume success
+		while (lmbase->l_prev) lmbase = lmbase->l_prev;
+	}
+	// this is a tiny bit crude, but basically okay. we just want to find
+	// something that roughly matches the basename, rather than needing an exact
+	// path, in a manner vaguely similar to Windows' GetModuleHandle(). that way
+	// we can just look up client.so or something without having to figure out
+	// where exactly that is.
+	for (struct link_map *lm = lmbase; lm; lm = lm->l_next) {
+		if (name[0] == '/') {
+			if (!strcmp(name, lm->l_name)) return lm;
+			continue;
+		}
+		int namelen = strlen(lm->l_name);
+		int sublen = strlen(name);
+		if (sublen >= namelen) continue;
+		if (lm->l_name[namelen - sublen - 1] == '/' && !memcmp(
+				lm->l_name + namelen - sublen, name, sublen)) {
+			return lm;
+		}
+	}
+	return 0;
+}
+
+int os_dlfile(void *lib, char *buf, int sz) {
+	struct link_map *lm = lib;
+	int ssz = strlen(lm->l_name) + 1;
+	if (ssz > sz) { errno = ENAMETOOLONG; return -1; }
+	memcpy(buf, lm->l_name, ssz);
+	return ssz;
+}
+#endif
+
+// vi: sw=4 ts=4 noet tw=80 cc=80
diff --git a/src/os.h b/src/os.h
index c954d1a..b599523 100644
--- a/src/os.h
+++ b/src/os.h
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2022 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2024 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
@@ -17,48 +17,238 @@
 #ifndef INC_OS_H
 #define INC_OS_H
 
-/*
- * Here we declare an absolute ton of wrappers, macros, compatibility shims,
- * reimplementations and so on to try in vain to sweep the inconsistencies
- * between Windows and not-Windows under the rug.
- */
+#include <string.h>
+#include <sys/stat.h> // XXX: try abstracting stat() and avoiding ucrt dep here
 
-#include <errno.h>
-#include <fcntl.h>
 #ifdef _WIN32
-#include <direct.h>
-#include <io.h>
-#include <wchar.h>
-// DUMB HACK: noreturn.h is alphabetically before os.h so including it after
-// looks weird and inconsistent. including it before breaks Windows.h though
-// because of __declspec(noreturn). Undef for now, and restore at the end of
-// this header.
-#undef noreturn
-#include <Windows.h>
-#include <winternl.h>
-#else
-#include <dlfcn.h>
-#include <limits.h>
-#include <link.h>
-#include <stdio.h>
-#include <string.h>
-#include <strings.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <unistd.h>
+
+#include <wchar.h> // XXX: there's kind of a lot of junk in this header!
+
+#define IMPORT __declspec(dllimport) // only needed for variables
+#define EXPORT __declspec(dllexport)
+
+typedef unsigned short os_char;
+#define _OS_CAT(x, y) x##y
+#define OS_LIT(x) _OS_CAT(L, x)
+#define os_strcmp wcscmp
+#define os_strlen wcslen
+// ucrt defines __stat64 to _stat64. we want _wstat64 to be the actual function
+#define _stat64(path, buf) _wstat64(path, buf)
+#define os_stat _stat64
+
+#define OS_DLPREFIX ""
+#define OS_DLSUFFIX ".dll"
+
+#define OS_MAIN wmain
+
+// add to these as needed...
+#define OS_EEXIST /*ERROR_ALREADY_EXISTS*/ 183
+#define OS_ENOENT /*ERROR_PATH_NOT_FOUND*/ 3
+
+// Further Windows-specific workarounds because Windows is great...
+
+#ifndef PATH_MAX
+// XXX: win32/crt has this dumb 260 limit even though the actual kernel imposes
+// no limit (though apparently NTFS has a limit of 65535). Theoretically we
+// could do some memes with UNC paths to extend it to at least have parity with
+// Unix PATH_MAX (4096), but for now we just kind of accept that Windows is a
+// disaster.
+#define PATH_MAX 260
 #endif
 
-// Things were getting unwieldy so they're now split into these headers...
-#ifdef _WIN32
-#include "os-win32.h"
-// DUMB HACK part 2: restore what the #including source file had asked for
-#ifdef INC_NORETURN_H
-#define noreturn _Noreturn void
+// windows doesn't define this for some reason!? note: add others as needed...
+#define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
+
+#define alloca _alloca // ugh!
+
+// one last thing: mprot constants are part of os.h API, whether or not
+// Windows.h was included. this is a bit of a hack, but whatever!
+#ifndef _INC_WINDOWS
+#define PAGE_NOACCESS			1
+#define PAGE_READONLY			2
+#define PAGE_READWRITE			4
+#define PAGE_EXECUTE_READ		32
+#define PAGE_EXECUTE_READWRITE	64
 #endif
+
 #else
-#include "os-unix.h"
+
+#include <errno.h> // meh
+
+#define IMPORT
+#ifdef __GNUC__
+#define EXPORT __attribute__((visibility("default"))
+#else
+#define EXPORT int exp[-!!"compiler needs a way to export symbols!"];
+#endif
+
+// trying to avoid pulling in unnecessary headers as much as possible: define
+// our own constants for os_mprot() / mprotect()
+#if defined(__linux__) // apparently linux is pretty much the sole oddball here!
+#define _OS_PROT_READ 4
+#define _OS_PROT_WRITE 2
+#define _OS_PROT_EXEC 1
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || \
+		defined(__DragonFly__) || defined(__sun) || defined(__serenity)
+#define _OS_PROT_READ 1
+#define _OS_PROT_WRITE 2
+#define _OS_PROT_EXEC 4
+#elif !defined(_WIN32) // what else could this possibly even be!?
+#include <sys/mman.h> // just fall back on this. not the end of the world...
+#define _OS_PROT_READ PROT_READ
+#define _OS_PROT_WRITE PROT_WRITE
+#define _OS_PROT_EXEC PROT_EXEC
 #endif
 
+typedef char os_char;
+#define OS_LIT(x) x
+#define os_strcmp strcmp
+#define os_strlen strlen
+#define os_stat stat
+
+#define OS_DLPREFIX "lib"
+#define OS_DLSUFFIX ".so"
+
+#define OS_MAIN main
+
+// unix mprotect flags are much nicer but cannot be defined in terms of the
+// windows ones, so we use the windows ones and define them in terms of the unix
+// ones. another victory for stupid!
+#define PAGE_NOACCESS			0
+#define PAGE_READONLY			_OS_PROT_READ
+#define PAGE_READWRITE			_OS_PROT_READ | _OS_PROT_WRITE
+#define PAGE_EXECUTE_READ		_OS_PROT_READ |                  _OS_PROT_EXEC
+#define PAGE_EXECUTE_READWRITE	_OS_PROT_READ | _OS_PROT_WRITE | _OS_PROT_EXEC
+
+#define OS_EEXIST EEXIST
+#define OS_ENOENT ENOENT
+
+#endif
+
+/* Copies n characters from src to dest, using the OS-specific char type. */
+static inline void os_spancopy(os_char *restrict dest,
+		const os_char *restrict src, int n) {
+	memcpy(dest, src, n * sizeof(os_char));
+}
+
+/*
+ * Returns the last error code from an OS function - equivalent to calling
+ * GetLastError() in Windows and reading errno in Unix-like operating systems.
+ * For standard libc functions (implemented by UCRT on Windows), the value of
+ * errno should be used directly instead.
+ */
+int os_lasterror(void);
+
+/*
+ * Opens a file for reading. Returns an OS-specific file handle, or -1 on error.
+ */
+int os_open_read(const os_char *path);
+
+/*
+ * Opens a file for writing, creating it if required. Returns an OS-specific
+ * file handle, or -1 on error.
+ */
+int os_open_write(const os_char *path);
+
+/*
+ * Opens a file for writing, creating it if required, or truncating it if it
+ * already exists. Returns an OS-specific file handle, or -1 on error.
+ */
+int os_open_writetrunc(const os_char *path);
+
+/*
+ * Reads up to max bytes from OS-specific file handle f into buf. Returns the
+ * number of bytes read, or -1 on error.
+ */
+int os_read(int f, void *buf, int max);
+
+/*
+ * Reads up to len bytes from buf to OS-specific file handle f. Returns the
+ * number of bytes written, or -1 on error. Generally the number of bytes
+ * written will be len, unless writing to a pipe/socket, which has a limited
+ * internal buffer, or possibly being preempted by a signal handler.
+ */
+int os_write(int f, const void *buf, int len);
+
+/*
+ * Returns the length of the on-disk file referred to by OS-specific file handle
+ * f, or -1 on error (the most likely error would be that the file is not
+ * actually on disk and instead refers to a pipe or something).
+ */
+long long os_fsize(int f);
+
+/*
+ * Closes the OS-specific file handle f. On Windows, this causes pending writes
+ * to be flushed; on Unix-likes, this generally happens asynchronously. If
+ * blocking is a concern when writing files to disk, some sort of thread pool
+ * should always be used.
+ */
+void os_close(int f);
+
+/*
+ * Gets the current working directory, which may be up to PATH_MAX characters in
+ * length (using the OS-specific character type).
+ */
+void os_getcwd(os_char buf[static PATH_MAX]);
+
+/*
+ * Tries to create a directory at path. Returns true on success, false on
+ * failure. One may wish to ignore a failure if the directory already exists;
+ * this can be done by checking if os_lasterror() returns OS_EEXIST.
+ */
+bool os_mkdir(const os_char *path);
+
+/*
+ * Tries to delete a file(name) at path. Returns true on success, false on
+ * failure. One may wish to ignore a failure if the file already doesn't exist;
+ * this can be done by checking if os_lasterror() returns OS_ENOENT.
+ *
+ * On some Unix-like operating systems, this may work on empty directories, but
+ * for portably reliable results, one should call os_rmdir() for that instead.
+ */
+bool os_unlink(const os_char *path);
+
+/*
+ * Tries to delete a directory at path. Returns true on success, false on
+ * failure. One may wish to ignore a failure if the directory already doesn't
+ * exist; this can be done by checking if os_lasterror() returns OS_ENOENT.
+ */
+bool os_rmdir(const os_char *path);
+
+/*
+ * Tries to look up the symbol sym from the shared library handle lib. Returns
+ * an opaque pointer on success, or null on failure.
+ */
+void *os_dlsym(void *restrict lib, const char *restrict sym);
+
+#if defined(_WIN32) || defined(__linux__)
+/*
+ * Tries to get a handle to an already-loaded shared library matching name.
+ * Returns the library handle on success, or null on failure.
+ */
+void *os_dlhandle(const os_char *name);
+
+/*
+ * Tries to determine the file path to the shared library handle lib, and stores
+ * it in buf (with max length given by sz). Returns the length of the resulting
+ * string, or -1 on failure.
+ */
+int os_dlfile(void *lib, os_char *buf, int sz);
+#endif
+
+/*
+ * Changes memory protection for the address range given by addr and len, using
+ * one of the Win32-style PAGE_* flags specified above. Returns true on success
+ * and false on failure.
+ */
+bool os_mprot(void *addr, int len, int mode);
+
+/*
+ * Fills buf with up to sz cryptographically random bytes. sz has an OS-specific
+ * upper limit - a safe value across all major operating systems is 256.
+ */
+void os_randombytes(void *buf, int sz);
+
 #endif
 
 // vi: sw=4 ts=4 noet tw=80 cc=80
diff --git a/src/sst.c b/src/sst.c
index de04b88..ce80032 100644
--- a/src/sst.c
+++ b/src/sst.c
@@ -14,13 +14,14 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-#ifndef _WIN32
-#include <stdlib.h> // unsetenv
-#endif
 #include <string.h>
 
 #ifdef _WIN32
+#include <Windows.h>
 #include <shlwapi.h>
+#else
+#include <stdlib.h> // unsetenv
+#include <sys/uio.h>
 #endif
 
 #include "con_.h"
@@ -74,8 +75,6 @@ static void *ownhandle(void) {
 	}
 	return cached;
 }
-
-struct gnu_link_map *_os_lmbase = 0; // XXX: stupid place to put this, oh well
 #endif
 
 #ifdef _WIN32
@@ -99,7 +98,7 @@ DEF_CCMD_HERE(sst_autoload_enable, "Register SST to load on game startup", 0) {
 	const os_char *startdir;
 	if (ifacever == 2) {
 		startdir = _startdir;
-		os_getcwd(_startdir, PATH_MAX); // if this fails, OS devs are all fired.
+		os_getcwd(_startdir);
 #ifdef _WIN32
 		// note: strictly speaking we *could* allow this with an absolute path
 		// since old builds allow absolute plugin_load paths but since it's less
@@ -112,13 +111,12 @@ DEF_CCMD_HERE(sst_autoload_enable, "Register SST to load on game startup", 0) {
 			errmsg_errorx("path to game is too long");
 			return;
 		}
-		memcpy(_startdir + len,
 #ifdef _WIN32
-				L"\\bin", // PathRelativePathToW actually NEEDS a backslash, UGH
+		// PathRelativePathToW actually NEEDS a backslash, UGH
+		os_spancopy(_startdir + len, L"\\bin", 5);
 #else
-				"/bin",
+		os_spancopy(_startdir + len, L"/bin", 5);
 #endif
-				5 * sizeof(os_char));
 	}
 	else /* ifacever == 3 */ {
 		// newer games load from the mod dir instead of engine bin, and search
@@ -143,8 +141,17 @@ DEF_CCMD_HERE(sst_autoload_enable, "Register SST to load on game startup", 0) {
 		errmsg_errorsys("couldn't compute a relative path");
 		return;
 	}
-	// arbitrary aesthetic judgement
-	for (ushort *p = relpath; *p; ++p) if (*p == L'\\') *p = L'/';
+	// arbitrary aesthetic judgement - use forward slashes. while we're at it,
+	// also make sure there's no unicode in there, just in case...
+	int rellen = 0;
+	for (ushort *p = relpath; *p; ++p, ++rellen) {
+		if (*p > 127) {
+			errmsg_errorx("mod dir contains Unicode characters which Source "
+					"doesn't handle well - autoload file not created");
+			return;
+		}
+		if (*p == L'\\') *p = L'/';
+	}
 #else
 	const char *p = path, *q = startdir;
 	int slash = 0;
@@ -177,27 +184,34 @@ c:	memcpy(r, p + slash + 1, rellen);
 		errmsg_errorx("path to VDF is too long");
 		return;
 	}
-	memcpy(path, gameinfo_gamedir, len * sizeof(*gameinfo_gamedir));
-	memcpy(path + len, OS_LIT("/addons"), 8 * sizeof(os_char));
-	if (os_mkdir(path) == -1 && errno != EEXIST) {
-		errmsg_errorstd("couldn't create %" fS, path);
+	os_spancopy(path, gameinfo_gamedir, len);
+	os_spancopy(path + len, OS_LIT("/addons"), 8);
+	if (!os_mkdir(path) && os_lasterror() != OS_EEXIST) {
+		errmsg_errorsys("couldn't create %" fS, path);
 		return;
 	}
-	memcpy(path + len + sizeof("/addons") - 1,
+	os_spancopy(path + len + sizeof("/addons") - 1,
 			OS_LIT("/") OS_LIT(VDFBASENAME) OS_LIT(".vdf"),
-			sizeof("/" VDFBASENAME ".vdf") * sizeof(os_char));
-	FILE *f = os_fopen(path, OS_LIT("wb"));
-	if (!f) {
-		errmsg_errorstd("couldn't open %" fS, path);
-		return;
-	}
-	// XXX: oh crap, we're clobbering unicode again. welp, let's continue
-	// relying on the theory that the engine would fail to deal with it anyway.
-	if (fprintf(f, "Plugin { file \"%" fS "\" }\n", relpath) < 0 ||
-			fflush(f) == -1) {
-		errmsg_errorstd("couldn't write to %" fS, path);
+			sizeof("/" VDFBASENAME ".vdf"));
+	int f = os_open_write(path);
+	if (f == -1) { errmsg_errorsys("couldn't open %" fS, path); return; }
+#ifdef _WIN32
+	char buf[19 + PATH_MAX];
+	memcpy(buf, "Plugin { file \"", 15);
+	for (int i = 0; i < rellen; ++i) buf[i + 15] = relpath[i];
+	memcpy(buf + 15 + rellen, "\" }\n", 4);
+	if (os_write(f, buf, rellen + 19) == -1) { // blegh
+#else
+	struct iovec iov[3] = {
+		{"Plugin { file \"", 15},
+		{relpath, rellen},
+		{"\" }\n", 4}
+	};
+	if (writev(fd, &iov, 3) == -1) {
+#endif
+		errmsg_errorsys("couldn't write to %" fS, path);
 	}
-	fclose(f);
+	os_close(f);
 }
 
 DEF_CCMD_HERE(sst_autoload_disable, "Stop loading SST on game startup", 0) {
@@ -208,11 +222,11 @@ DEF_CCMD_HERE(sst_autoload_disable, "Stop loading SST on game startup", 0) {
 		errmsg_errorx("path to VDF is too long");
 		return;
 	}
-	memcpy(path, gameinfo_gamedir, len * sizeof(*gameinfo_gamedir));
-	memcpy(path + len, OS_LIT("/addons/") OS_LIT(VDFBASENAME) OS_LIT(".vdf"),
-			sizeof("/addons/" VDFBASENAME ".vdf") * sizeof(os_char));
-	if (os_unlink(path) == -1 && errno != ENOENT) {
-		errmsg_warnstd("couldn't delete %" fS, path);
+	os_spancopy(path, gameinfo_gamedir, len);
+	os_spancopy(path + len, OS_LIT("/addons/") OS_LIT(VDFBASENAME) OS_LIT(".vdf"),
+			sizeof("/addons/" VDFBASENAME ".vdf"));
+	if (!os_unlink(path) && os_lasterror() != OS_ENOENT) {
+		errmsg_warnsys("couldn't delete %" fS, path);
 	}
 }
 
diff --git a/src/stubs/BCryptPrimitives.c b/src/stubs/BCryptPrimitives.c
new file mode 100644
index 0000000..afcaa7e
--- /dev/null
+++ b/src/stubs/BCryptPrimitives.c
@@ -0,0 +1,6 @@
+/* This file is dedicated to the public domain. */
+
+// We have to define a real function with the right number of arguments to get
+// the mangled symbol _ProcessPrng@8, which the .def file apparently turns
+// into an "undecorate" .lib entry through some undocumented magic (of course!).
+int __stdcall ProcessPrng(void *x, unsigned int y) { return 0; }
diff --git a/src/stubs/bcryptprimitives.def b/src/stubs/bcryptprimitives.def
new file mode 100644
index 0000000..9021d7c
--- /dev/null
+++ b/src/stubs/bcryptprimitives.def
@@ -0,0 +1,7 @@
+; This file is dedicated to the public domain.
+
+LIBRARY bcryptprimitives
+EXPORTS
+	ProcessPrng
+
+; vi: sw=4 ts=4 noet tw=80 cc=80
diff --git a/test/hook.test.c b/test/hook.test.c
index 7cbfd15..a2447cc 100644
--- a/test/hook.test.c
+++ b/test/hook.test.c
@@ -6,6 +6,7 @@
 
 #include "../src/x86.c"
 #include "../src/hook.c"
+#include "../src/os.c"
 
 #include <stdarg.h>
 #include <stdio.h>