Merge pull request #19097 from Kethen/sysclib_sprintf

implement sysclib_sprintf
hrydgard · May 1, 2024 · 59be4b0 · 59be4b0
2 parents edcf685 + fa0eaeb
commit 59be4b0
Showing 1 changed file with 153 additions and 5 deletions.
diff --git a/Core/HLE/sceKernelInterrupt.cpp b/Core/HLE/sceKernelInterrupt.cpp
@@ -742,14 +742,162 @@ static int sysclib_memcmp(u32 dst, u32 src, u32 size) {
 }
 
 static int sysclib_sprintf(u32 dst, u32 fmt) {
-	ERROR_LOG(SCEKERNEL, "Unimpl sysclib_sprintf(dest=%08x, src=%08x)", dst, fmt);
-	if (Memory::IsValidAddress(dst) && Memory::IsValidAddress(fmt)) {
-		// TODO: Properly use the format string with more parameters.
-		return sprintf((char *)Memory::GetPointerUnchecked(dst), "%s", Memory::GetCharPointerUnchecked(fmt));
-	} else {
+	ERROR_LOG(SCEKERNEL, "Untested sysclib_sprintf(dst=%08x, fmt=%08x)", dst, fmt);
+	if (!Memory::IsValidAddress(dst) || !Memory::IsValidAddress(fmt)) {
 		// What to do? Crash, probably.
 		return 0;
 	}
+
+	DEBUG_LOG(SCEKERNEL, "sysclib_sprintf fmt: %s", Memory::GetCharPointerUnchecked(fmt));
+	DEBUG_LOG(SCEKERNEL, "sysclib_sprintf a0-a4, t0-t4: 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x",
+	currentMIPS->r[MIPS_REG_A0],
+	currentMIPS->r[MIPS_REG_A1],
+	currentMIPS->r[MIPS_REG_A2],
+	currentMIPS->r[MIPS_REG_A3],
+	currentMIPS->r[MIPS_REG_T0],
+	currentMIPS->r[MIPS_REG_T1],
+	currentMIPS->r[MIPS_REG_T2],
+	currentMIPS->r[MIPS_REG_T3]
+	);
+
+	bool processing_specifier = false;
+	std::string specifier = "";
+	int bytes_to_read = 0;
+	int arg_idx = 0;
+	int fmt_len = 0;
+	std::string result = "";
+	for (const char *c = Memory::GetCharPointerUnchecked(fmt); *c != '\0'; c++) {
+		// in case we have a bad fmt string, try not to crash the whole emulator
+		fmt_len++;
+		if (fmt_len == 1024) {
+			ERROR_LOG(SCEKERNEL, "sysclib_sprintf fmt is longer than 1024");
+			return 0;
+		}
+
+		if (!processing_specifier) {
+			if (*c == '%') {
+				specifier = "%";
+				processing_specifier = true;
+				bytes_to_read = 0;
+			} else {
+				result.append(1, *c);
+			}
+		} else {
+			specifier.append(1, *c);
+
+			// going by https://cplusplus.com/reference/cstdio/printf/#compatibility
+			// no idea what the kernel module really supports as of writing this
+			switch (*c) {
+			case '%':
+			{
+				result.append(specifier);
+				processing_specifier = false;
+				break;
+			}
+			case 's':
+			{
+				// consume 4 bytes from arguments
+				u32 val = 0;
+				if (arg_idx <= 1) {
+					val = currentMIPS->r[MIPS_REG_A2 + arg_idx];
+				} else if(arg_idx <= 5) {
+					val = currentMIPS->r[MIPS_REG_T0 + arg_idx - 2];
+				} else {
+					int stack_idx = arg_idx - 6;
+					u32 stack_cur = currentMIPS->r[MIPS_REG_SP] + stack_idx * 4;
+
+					if (!Memory::IsValidAddress(stack_cur)) {
+						ERROR_LOG(SCEKERNEL, "sysclib_sprintf bad stack pointer %08x", stack_cur);
+						return 0;
+					}
+					val = Memory::Read_U32(stack_cur);
+					DEBUG_LOG(SCEKERNEL, "sysclib_sprintf fetching %08x from sp + %u", val, stack_idx * 4);
+				}
+				arg_idx++;
+
+				if (!Memory::IsValidAddress(val)) {
+					ERROR_LOG(SCEKERNEL, "sysclib_sprintf bad string reference %08x", val);
+					return 0;
+				}
+
+				const char *str = Memory::GetCharPointerUnchecked(val);
+				// limit the string length and hope that we don't crash on a bad string reference
+				char buf[1024] = {0};
+				strncpy(buf, str, sizeof(buf));
+				buf[sizeof(buf) - 1] = '\0';
+				result.append(buf);
+				processing_specifier = false;
+				break;
+			}
+			case 'd':
+			case 'i':
+			case 'u':
+			case 'o':
+			case 'x':
+			case 'X':
+			case 'f':
+			case 'e':
+			case 'E':
+			case 'g':
+			case 'G':
+			case 'c':
+			case 'p':
+			case 'n':
+			{
+				u64 val = 0;
+				if (bytes_to_read == 0) {
+					bytes_to_read = 4;
+				}
+				int read_cnt = 0;
+				while (bytes_to_read != 0) {
+					u32 val_from_arg = 0;
+					if (arg_idx <= 1) {
+						val_from_arg = currentMIPS->r[MIPS_REG_A2 + arg_idx];
+					} else if (arg_idx <= 5) {
+						val_from_arg = currentMIPS->r[MIPS_REG_T0 + arg_idx - 2];
+					} else {
+						int stack_idx = arg_idx - 6;
+						u32 stack_cur = currentMIPS->r[MIPS_REG_SP] + stack_idx * 4;
+
+						if (!Memory::IsValidAddress(stack_cur)) {
+							ERROR_LOG(SCEKERNEL, "sysclib_sprintf bad stack pointer %08x", stack_cur);
+							return 0;
+						}
+						val_from_arg = Memory::Read_U32(stack_cur);
+						DEBUG_LOG(SCEKERNEL, "sysclib_sprintf fetching %08x from sp + %u", val_from_arg, stack_idx * 4);
+					}
+					arg_idx++;
+
+					val = val | ((u64)val_from_arg << (read_cnt * 32));
+
+					bytes_to_read = bytes_to_read - 4;
+					read_cnt++;
+				}
+				char buf[1024] = {0};
+				snprintf(buf, sizeof(buf), specifier.c_str(), val);
+				buf[sizeof(buf) - 1] = '\0';
+				result.append(buf);
+				processing_specifier = false;
+				break;
+			}
+			case 'h':
+			{
+				// allegrex calling convention is 4 bytes aligned
+				bytes_to_read = 4;
+				break;
+			}
+			case 'l':
+			{
+				bytes_to_read = bytes_to_read + 4;
+				break;
+			}
+			}
+		}
+	}
+
+	// if a small buffer was allocated by the program, we will likely crash
+	strcpy((char *)Memory::GetPointerUnchecked(dst), result.c_str());
+	return result.length();
 }
 
 static u32 sysclib_memset(u32 destAddr, int data, int size) {