Add argument validation to most libpsn00b functions

13 files changed, 139 insertions, 22 deletions

diff --git a/libpsn00b/include/assert.h b/libpsn00b/include/assert.h
index d18a56f..26b2023 100644
--- a/libpsn00b/include/assert.h
+++ b/libpsn00b/include/assert.h
@@ -25,6 +25,9 @@ void _assert_abort(const char *file, int line, const char *expr);
 
 #define assert(expr)
 #define _sdk_log(fmt, ...)
+#define _sdk_assert(expr, fmt, ...)
+#define _sdk_validate_args_void(expr)
+#define _sdk_validate_args(expr, ret)
 
 #else
 
@@ -39,6 +42,22 @@ void _assert_abort(const char *file, int line, const char *expr);
 	printf(fmt __VA_OPT__(,) __VA_ARGS__)
 #endif
 
+#define _sdk_assert(expr, ret, fmt, ...) \
+	if (!(expr)) { \
+		_sdk_log(fmt, __VA_ARGS__); \
+		return ret; \
+	}
+#define _sdk_validate_args_void(expr) \
+	if (!(expr)) { \
+		_sdk_log("invalid args to %s() (%s)\n", __func__, #expr); \
+		return; \
+	}
+#define _sdk_validate_args(expr, ret) \
+	if (!(expr)) { \
+		_sdk_log("invalid args to %s() (%s)\n", __func__, #expr); \
+		return ret; \
+	}
+
 #endif
 
 #endif
diff --git a/libpsn00b/psxcd/cdread.c b/libpsn00b/psxcd/cdread.c
index d211a01..1adc255 100644
--- a/libpsn00b/psxcd/cdread.c
+++ b/libpsn00b/psxcd/cdread.c
@@ -89,6 +89,8 @@ static int _poll_retry(void) {
 /* Public API */
 
 int CdReadRetry(int sectors, uint32_t *buf, int mode, int attempts) {
+	_sdk_validate_args((sectors > 0) && buf && (attempts > 0), -1);
+
 	if (CdReadSync(1, 0) > 0) {
 		_sdk_log("CdRead() failed, another read in progress (%d sectors pending)\n", _pending_sectors);
 		return 0;
diff --git a/libpsn00b/psxcd/common.c b/libpsn00b/psxcd/common.c
index c8f01d1..461ab91 100644
--- a/libpsn00b/psxcd/common.c
+++ b/libpsn00b/psxcd/common.c
@@ -244,6 +244,8 @@ int CdInit(void) {
 /* Low-level command API */
 
 int CdCommandF(CdlCommand cmd, const void *param, int length) {
+	_sdk_validate_args(param || (length <= 0), -1);
+
 	const uint8_t *_param = (const uint8_t *) param;
 
 	_last_command = (uint8_t) cmd;
@@ -283,7 +285,7 @@ int CdCommandF(CdlCommand cmd, const void *param, int length) {
 		__asm__ volatile("");
 
 	CD_REG(0) = 0;
-	for (; length; length--)
+	for (; length > 0; length--)
 		CD_REG(2) = *(_param++);
 
 	CD_REG(0) = 0;
@@ -292,6 +294,8 @@ int CdCommandF(CdlCommand cmd, const void *param, int length) {
 }
 
 int CdCommand(CdlCommand cmd, const void *param, int length, uint8_t *result) {
+	_sdk_validate_args(param || (length <= 0), -1);
+
 	/*if (_ack_pending) {
 		_sdk_log("CdCommand(0x%02x) failed, drive busy\n", cmd);
 		return 0;
@@ -329,8 +333,10 @@ int CdControlF(CdlCommand cmd, const void *param) {
 	} else {
 		// The command takes a mandatory parameter or no parameter.
 		length = flags & 3;
-		if (length && !param)
+		if (length && !param) {
+			_sdk_log("CdControl() param is required for command 0x%02x\n", cmd);
 			return -1;
+		}
 	}
 
 	return CdCommandF(cmd, param, length);
diff --git a/libpsn00b/psxcd/isofs.c b/libpsn00b/psxcd/isofs.c
index 0ac782b..5fd0536 100644
--- a/libpsn00b/psxcd/isofs.c
+++ b/libpsn00b/psxcd/isofs.c
@@ -450,6 +450,8 @@ static char* get_filename(char *name, const char *filename)
 
 CdlFILE *CdSearchFile(CdlFILE *fp, const char *filename)
 {
+	_sdk_validate_args(fp && filename, NULL);
+
 	int i,j,found_dir,num_dirs;
 	int dir_len;
 	char tpath_rbuff[128];
@@ -553,6 +555,8 @@ CdlFILE *CdSearchFile(CdlFILE *fp, const char *filename)
 
 CdlDIR *CdOpenDir(const char* path)
 {
+	_sdk_validate_args(path, NULL);
+
 	CdlDIR_INT*	dir;
 	int			num_dirs;
 	int			i,found_dir;
@@ -631,6 +635,8 @@ CdlDIR *CdOpenDir(const char* path)
 
 int CdReadDir(CdlDIR *dir, CdlFILE* file)
 {
+	_sdk_validate_args(dir && file, 0);
+
 	CdlDIR_INT*		d_dir;
 	ISO_DIR_ENTRY*	dir_entry;
 
@@ -683,6 +689,9 @@ int CdReadDir(CdlDIR *dir, CdlFILE* file)
 
 void CdCloseDir(CdlDIR *dir)
 {
+	if (!dir)
+		return;
+
 	CdlDIR_INT*	d_dir;
 	
 	d_dir = (CdlDIR_INT*)dir;
@@ -698,6 +707,8 @@ int CdIsoError()
 
 int CdGetVolumeLabel(char *label)
 {
+	_sdk_validate_args(label, -1);
+
 	int i, length = 31;
 	ISO_DESCRIPTOR* descriptor;
 
@@ -761,6 +772,8 @@ static void _scan_callback(CdlIntrResult status, unsigned char *result)
 
 int CdLoadSession(int session)
 {
+	_sdk_validate_args(session >= 0, -1);
+
 	CdlLOC *loc;
 	CdlCB ready_oldcb;
 	char scanbuff[2048];
diff --git a/libpsn00b/psxcd/misc.c b/libpsn00b/psxcd/misc.c
index 851fea6..2f04821 100644
--- a/libpsn00b/psxcd/misc.c
+++ b/libpsn00b/psxcd/misc.c
@@ -33,6 +33,8 @@ static const char *const _unlock_regions[] = {
 /* Sector DMA transfer functions */
 
 int CdGetSector(void *madr, int size) {
+	_sdk_validate_args(madr && (size > 0), 0);
+
 	//while (!(CD_REG(0) & (1 << 6)))
 		//__asm__ volatile("");
 
@@ -47,6 +49,8 @@ int CdGetSector(void *madr, int size) {
 }
 
 int CdGetSector2(void *madr, int size) {
+	_sdk_validate_args(madr && (size > 0), 0);
+
 	//while (!(CD_REG(0) & (1 << 6)))
 		//__asm__ volatile("");
 
@@ -170,6 +174,8 @@ int CdUnlock(CdlRegionCode region) {
 /* Misc. functions */
 
 int CdGetToc(CdlLOC *toc) {
+	_sdk_validate_args(toc, 0);
+
 	uint8_t result[4];
 
 	if (!CdCommand(CdlGetTN, 0, 0, result))
@@ -199,6 +205,8 @@ int CdGetToc(CdlLOC *toc) {
 }
 
 int CdMix(const CdlATV *vol) {
+	_sdk_validate_args(vol, 0);
+
 	CD_REG(0) = 2;
 	CD_REG(2) = vol->val0;
 	CD_REG(3) = vol->val1;
diff --git a/libpsn00b/psxetc/dl.c b/libpsn00b/psxetc/dl.c
index ff712eb..06302e2 100644
--- a/libpsn00b/psxetc/dl.c
+++ b/libpsn00b/psxetc/dl.c
@@ -112,6 +112,8 @@ static uint32_t _elf_hash(const char *str) {
 /* Symbol map loading/introspection API */
 
 int DL_InitSymbolMap(int num_entries) {
+	_sdk_validate_args(num_entries, -1);
+
 	if (_symbol_map.entries)
 		DL_UnloadSymbolMap();
 
@@ -151,6 +153,8 @@ void DL_UnloadSymbolMap(void) {
 }
 
 void DL_AddMapSymbol(const char *name, void *ptr) {
+	_sdk_validate_args_void(name);
+
 	uint32_t hash  = _elf_hash(name);
 	int      index = _symbol_map.index;
 	_symbol_map.index = index + 1;
@@ -168,6 +172,8 @@ void DL_AddMapSymbol(const char *name, void *ptr) {
 }
 
 int DL_ParseSymbolMap(const char *ptr, size_t size) {
+	_sdk_validate_args(ptr && size, 0);
+
 	int entries = 0;
 
 	// Perform a quick scan over the entire map text and count the number of
@@ -232,6 +238,8 @@ int DL_ParseSymbolMap(const char *ptr, size_t size) {
 }
 
 void *DL_GetMapSymbol(const char *name) {
+	_sdk_validate_args(name, 0);
+
 	if (!_symbol_map.entries) {
 		_sdk_log("DL_GetMapSymbol() with no map loaded\n");
 		return 0;
@@ -275,8 +283,7 @@ void *DL_SetResolveCallback(void *(*callback)(DLL *, const char *)) {
 /* Library loading and linking API */
 
 DLL *DL_CreateDLL(DLL *dll, void *ptr, size_t size, DL_ResolveMode mode) {
-	if (!dll || !ptr)
-		return 0;
+	_sdk_validate_args(dll && ptr && size, 0);
 
 	dll->ptr        = ptr;
 	dll->malloc_ptr = (mode & DL_FREE_ON_DESTROY) ? ptr : 0;
@@ -463,6 +470,8 @@ void DL_DestroyDLL(DLL *dll) {
 }
 
 void *DL_GetDLLSymbol(const DLL *dll, const char *name) {
+	_sdk_validate_args(name, 0);
+
 	if (!dll)
 		return DL_GetMapSymbol(name);
 		//return _dl_resolve_callback(0, name);
diff --git a/libpsn00b/psxetc/interrupts.c b/libpsn00b/psxetc/interrupts.c
index 7c8b206..b7bbd07 100644
--- a/libpsn00b/psxetc/interrupts.c
+++ b/libpsn00b/psxetc/interrupts.c
@@ -4,6 +4,7 @@
  */
 
 #include <stdint.h>
+#include <assert.h>
 #include <psxapi.h>
 #include <psxetc.h>
 #include <hwregs_c.h>
@@ -99,8 +100,7 @@ static void _global_dma_handler(void) {
 /* IRQ and DMA handler API */
 
 void *InterruptCallback(IRQ_Channel irq, void (*func)(void)) {
-	if ((irq < 0) || (irq >= NUM_IRQ_CHANNELS))
-		return 0;
+	_sdk_validate_args((irq >= 0) && (irq < NUM_IRQ_CHANNELS), 0);
 
 	void *old_callback = _irq_handlers[irq];
 	_irq_handlers[irq] = func;
@@ -116,15 +116,13 @@ void *InterruptCallback(IRQ_Channel irq, void (*func)(void)) {
 }
 
 void *GetInterruptCallback(IRQ_Channel irq) {
-	if ((irq < 0) || (irq >= NUM_IRQ_CHANNELS))
-		return 0;
+	_sdk_validate_args((irq >= 0) && (irq < NUM_IRQ_CHANNELS), 0);
 
 	return _irq_handlers[irq];
 }
 
 void *DMACallback(DMA_Channel dma, void (*func)(void)) {
-	if ((dma < 0) || (dma >= NUM_DMA_CHANNELS))
-		return 0;
+	_sdk_validate_args((dma >= 0) && (dma < NUM_DMA_CHANNELS), 0);
 
 	void *old_callback = _dma_handlers[dma];
 	_dma_handlers[dma] = func;
@@ -151,8 +149,7 @@ void *DMACallback(DMA_Channel dma, void (*func)(void)) {
 }
 
 void *GetDMACallback(DMA_Channel dma) {
-	if ((dma < 0) || (dma >= NUM_DMA_CHANNELS))
-		return 0;
+	_sdk_validate_args((dma >= 0) && (dma < NUM_DMA_CHANNELS), 0);
 
 	return _dma_handlers[dma];
 }
@@ -160,8 +157,7 @@ void *GetDMACallback(DMA_Channel dma) {
 /* DMA channel priority API */
 
 int SetDMAPriority(DMA_Channel dma, int priority) {
-	if ((dma < 0) || (dma >= NUM_DMA_CHANNELS))
-		return -1;
+	_sdk_validate_args((dma >= 0) && (dma < NUM_DMA_CHANNELS), -1);
 
 	uint32_t dpcr    = DMA_DPCR;
 	uint32_t channel = dpcr >> (dma * 4);
@@ -175,8 +171,7 @@ int SetDMAPriority(DMA_Channel dma, int priority) {
 }
 
 int GetDMAPriority(DMA_Channel dma) {
-	if ((dma < 0) || (dma >= NUM_DMA_CHANNELS))
-		return -1;
+	_sdk_validate_args((dma >= 0) && (dma < NUM_DMA_CHANNELS), -1);
 
 	uint32_t channel = DMA_DPCR >> (dma * 4);
 	return (channel & 8) ? (channel & 7) : -1;
diff --git a/libpsn00b/psxgpu/common.c b/libpsn00b/psxgpu/common.c
index e354261..46f87bc 100644
--- a/libpsn00b/psxgpu/common.c
+++ b/libpsn00b/psxgpu/common.c
@@ -187,6 +187,8 @@ int EnqueueDrawOp(
 	uint32_t	arg2,
 	uint32_t	arg3
 ) {
+	_sdk_validate_args(func, -1);
+
 	// If GPU DMA is currently busy, append the command to the queue instead of
 	// executing it immediately. Note that interrupts must be disabled *prior*
 	// to checking if DMA is busy; disabling them afterwards would create a
@@ -263,6 +265,8 @@ void *DrawSyncCallback(void (*func)(void)) {
 /* OT and primitive drawing API */
 
 void ClearOTagR(uint32_t *ot, size_t length) {
+	_sdk_validate_args_void(ot && length);
+
 	DMA_MADR(DMA_OTC) = (uint32_t) &ot[length - 1];
 	DMA_BCR(DMA_OTC)  = length & 0xffff;
 	DMA_CHCR(DMA_OTC) = 0x11000002;
@@ -272,6 +276,8 @@ void ClearOTagR(uint32_t *ot, size_t length) {
 }
 
 void ClearOTag(uint32_t *ot, size_t length) {
+	_sdk_validate_args_void(ot && length);
+
 	// DMA6 only supports writing to RAM in reverse order (last to first), so
 	// the OT has to be cleared in software here. This function is thus much
 	// slower than ClearOTagR().
@@ -285,10 +291,14 @@ void ClearOTag(uint32_t *ot, size_t length) {
 }
 
 void AddPrim(uint32_t *ot, const void *pri) {
+	_sdk_validate_args_void(ot && pri);
+
 	addPrim(ot, pri);
 }
 
-void DrawPrim(const uint32_t *pri) {	
+void DrawPrim(const uint32_t *pri) {
+	_sdk_validate_args_void(pri);
+
 	size_t length = getlen(pri);
 
 	DrawSync(0);
@@ -308,10 +318,14 @@ void DrawPrim(const uint32_t *pri) {
 }
 
 int DrawOTag(const uint32_t *ot) {
+	_sdk_validate_args(ot, -1);
+
 	return EnqueueDrawOp((void *) &DrawOTag2, (uint32_t) ot, 0, 0);
 }
 
 void DrawOTag2(const uint32_t *ot) {
+	_sdk_validate_args_void(ot);
+
 	GPU_GP1 = 0x04000002; // Enable DMA request, route to GP0
 
 	while (DMA_CHCR(DMA_GPU) & (1 << 24))
diff --git a/libpsn00b/psxgpu/env.c b/libpsn00b/psxgpu/env.c
index b90a431..cfe09c0 100644
--- a/libpsn00b/psxgpu/env.c
+++ b/libpsn00b/psxgpu/env.c
@@ -4,6 +4,7 @@
  */
 
 #include <stdint.h>
+#include <assert.h>
 #include <psxgpu.h>
 #include <hwregs_c.h>
 
@@ -36,6 +37,8 @@ static inline uint32_t _get_window_mask(int size) {
 /* Drawing API */
 
 DRAWENV *SetDefDrawEnv(DRAWENV *env, int x, int y, int w, int h) {
+	_sdk_validate_args(env && (w > 0) && (h > 0), 0);
+
 	env->clip.x = x;
 	env->clip.y = y;
 	env->clip.w = w;
@@ -60,6 +63,8 @@ DRAWENV *SetDefDrawEnv(DRAWENV *env, int x, int y, int w, int h) {
 }
 
 int DrawOTagEnv(const uint32_t *ot, DRAWENV *env) {
+	_sdk_validate_args(ot && env, -1);
+
 	// All commands are grouped into a single display list packet for
 	// performance reasons using tagless primitives (the GPU does not care
 	// about the grouping as the display list is parsed by the CPU).
@@ -102,6 +107,8 @@ int DrawOTagEnv(const uint32_t *ot, DRAWENV *env) {
 }
 
 void PutDrawEnv(DRAWENV *env) {
+	_sdk_validate_args_void(env);
+
 	DrawOTagEnv((const uint32_t *) 0x00ffffff, env);
 }
 
@@ -109,6 +116,8 @@ void PutDrawEnv(DRAWENV *env) {
 // useful if the DRAWENV structure is never modified (which is the case most of
 // the time).
 void PutDrawEnvFast(DRAWENV *env) {
+	_sdk_validate_args_void(env);
+
 	if (!(env->dr_env.tag))
 		DrawOTagEnv((const uint32_t *) 0x00ffffff, env);
 	else
@@ -118,6 +127,8 @@ void PutDrawEnvFast(DRAWENV *env) {
 /* Display API */
 
 DISPENV *SetDefDispEnv(DISPENV *env, int x, int y, int w, int h) {
+	_sdk_validate_args(env && (w > 0) && (h > 0), 0);
+
 	env->disp.x = x;
 	env->disp.y = y;
 	env->disp.w = w;
@@ -136,6 +147,8 @@ DISPENV *SetDefDispEnv(DISPENV *env, int x, int y, int w, int h) {
 }
 
 void PutDispEnv(const DISPENV *env) {
+	_sdk_validate_args_void(env);
+
 	uint32_t h_range, v_range, mode, fb_pos;
 
 	mode  = _gpu_video_mode << 3;
@@ -204,6 +217,8 @@ void PutDispEnv(const DISPENV *env) {
 /* Deprecated "raw" display API */
 
 void PutDispEnvRaw(const DISPENV_RAW *env) {
+	_sdk_validate_args_void(env);
+
 	uint32_t h_range, v_range, fb_pos;
 
 	h_range  =   608 + env->vid_xpos;
diff --git a/libpsn00b/psxgpu/font.c b/libpsn00b/psxgpu/font.c
index b1c3c7a..c9d60f1 100644
--- a/libpsn00b/psxgpu/font.c
+++ b/libpsn00b/psxgpu/font.c
@@ -1,4 +1,5 @@
 #include <stdint.h>
+#include <assert.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -23,6 +24,7 @@ uint16_t _font_clut;
 extern uint8_t _gpu_debug_font[];
 
 void FntLoad(int x, int y) {
+	_sdk_validate_args_void((x >= 0) && (y >= 0) && (x < 1024) && (y < 1024));
 
 	RECT pos;
 	TIM_IMAGE tim;
@@ -66,7 +68,8 @@ void FntLoad(int x, int y) {
 }
 
 int FntOpen(int x, int y, int w, int h, int isbg, int n) {
-	
+	_sdk_validate_args((w > 0) && (h > 0) && (n > 0), -1);
+
 	int i;
 	
 	// Initialize a text stream
@@ -98,7 +101,8 @@ int FntOpen(int x, int y, int w, int h, int isbg, int n) {
 }
 
 int FntPrint(int id, const char *fmt, ...) {
-	
+	_sdk_validate_args((id < _nstreams) && fmt, -1);
+
 	int n;
 	va_list ap;
 
@@ -124,7 +128,8 @@ int FntPrint(int id, const char *fmt, ...) {
 }
 
 char *FntFlush(int id) {
-	
+	_sdk_validate_args(id < _nstreams, 0);
+
 	char		*opri;
 	SPRT_8		*sprt;
 	DR_TPAGE	*tpage;
@@ -226,7 +231,8 @@ char *FntFlush(int id) {
 }
 
 char *FntSort(uint32_t *ot, char *pri, int x, int y, const char *text) {
-	
+	_sdk_validate_args(ot && pri, 0);
+
 	DR_TPAGE *tpage;
 	SPRT_8 *sprt = (SPRT_8*)pri;
 	int	i;
diff --git a/libpsn00b/psxgpu/image.c b/libpsn00b/psxgpu/image.c
index ba5c445..63bceb6 100644
--- a/libpsn00b/psxgpu/image.c
+++ b/libpsn00b/psxgpu/image.c
@@ -69,6 +69,8 @@ static void _dma_transfer(const RECT *rect, uint32_t *data, int write) {
 /* VRAM transfer API */
 
 int LoadImage(const RECT *rect, const uint32_t *data) {
+	_sdk_validate_args(rect && data, -1);
+
 	int index = _next_saved_rect;
 
 	_saved_rects[index] = *rect;
@@ -83,6 +85,8 @@ int LoadImage(const RECT *rect, const uint32_t *data) {
 }
 
 int StoreImage(const RECT *rect, uint32_t *data) {
+	_sdk_validate_args(rect && data, -1);
+
 	int index = _next_saved_rect;
 
 	_saved_rects[index] = *rect;
@@ -97,18 +101,26 @@ int StoreImage(const RECT *rect, uint32_t *data) {
 }
 
 int MoveImage(const RECT *rect, int x, int y) {
+	_sdk_validate_args(rect, -1);
+
 	return EnqueueDrawOp((void *) &MoveImage2, (uint32_t) rect, x, y);
 }
 
 void LoadImage2(const RECT *rect, const uint32_t *data) {
+	_sdk_validate_args_void(rect && data);
+
 	_dma_transfer(rect, (uint32_t *) data, 1);
 }
 
 void StoreImage2(const RECT *rect, uint32_t *data) {
+	_sdk_validate_args_void(rect && data);
+
 	_dma_transfer(rect, data, 0);
 }
 
 void MoveImage2(const RECT *rect, int x, int y) {
+	_sdk_validate_args_void(rect);
+
 	while (!(GPU_GP1 & (1 << 26)))
 		__asm__ volatile("");
 
@@ -131,6 +143,8 @@ void MoveImage2(const RECT *rect, int x, int y) {
 // returning pointers to them, which become useless once the .TIM file is
 // unloaded from main RAM.
 int GsGetTimInfo(const uint32_t *tim, GsIMAGE *info) {
+	_sdk_validate_args(tim && info, 1);
+
 	if ((*(tim++) & 0xffff) != 0x0010)
 		return 1;
 
@@ -157,6 +171,8 @@ int GsGetTimInfo(const uint32_t *tim, GsIMAGE *info) {
 }
 
 int GetTimInfo(const uint32_t *tim, TIM_IMAGE *info) {
+	_sdk_validate_args(tim && info, 1);
+
 	if ((*(tim++) & 0xffff) != 0x0010)
 		return 1;
 
diff --git a/libpsn00b/psxpress/mdec.c b/libpsn00b/psxpress/mdec.c
index 394a0ce..b3aa837 100644
--- a/libpsn00b/psxpress/mdec.c
+++ b/libpsn00b/psxpress/mdec.c
@@ -111,6 +111,8 @@ void DecDCTPutEnv(const DECDCTENV *env, int mono) {
 }
 
 void DecDCTin(const uint32_t *data, int mode) {
+	_sdk_validate_args_void(data);
+
 	uint32_t header = *data;
 	DecDCTinSync(0);
 
@@ -128,6 +130,8 @@ void DecDCTin(const uint32_t *data, int mode) {
 // data length as an argument rather than parsing it from the first 4 bytes of
 // the stream.
 void DecDCTinRaw(const uint32_t *data, size_t length) {
+	_sdk_validate_args_void(data && length);
+
 	if ((length >= DMA_CHUNK_LENGTH) && (length % DMA_CHUNK_LENGTH)) {
 		_sdk_log("input data length (%d) is not a multiple of %d, rounding\n", length, DMA_CHUNK_LENGTH);
 		length += DMA_CHUNK_LENGTH - 1;
@@ -157,6 +161,8 @@ int DecDCTinSync(int mode) {
 }
 
 void DecDCTout(uint32_t *data, size_t length) {
+	_sdk_validate_args_void(data && length);
+
 	DecDCToutSync(0);
 
 	if ((length >= DMA_CHUNK_LENGTH) && (length % DMA_CHUNK_LENGTH)) {
diff --git a/libpsn00b/psxspu/common.c b/libpsn00b/psxspu/common.c
index 1275621..efe1d9e 100644
--- a/libpsn00b/psxspu/common.c
+++ b/libpsn00b/psxspu/common.c
@@ -164,12 +164,18 @@ void SpuInit(void) {
 }
 
 size_t SpuRead(uint32_t *data, size_t size) {
+	_sdk_validate_args(data && size, 0);
+
 	return _dma_transfer(data, size, 0) * 4;
 }
 
 size_t SpuWrite(const uint32_t *data, size_t size) {
-	if (_transfer_addr < WRITABLE_AREA_ADDR)
+	_sdk_validate_args(data && size, 0);
+
+	if (_transfer_addr < WRITABLE_AREA_ADDR) {
+		_sdk_log("ignoring attempt to write to capture buffers at 0x%05x\n", _transfer_addr);
 		return 0;
+	}
 
 	// I/O transfer mode is not that useful, but whatever.
 	if (_transfer_mode)
@@ -179,6 +185,8 @@ size_t SpuWrite(const uint32_t *data, size_t size) {
 }
 
 size_t SpuWritePartly(const uint32_t *data, size_t size) {
+	//_sdk_validate_args(data && size, 0);
+
 	size_t _size = SpuWrite(data, size);
 
 	_transfer_addr += (_size + 1) / 2;