From c639d071e53d5565bb4df1157bcd133bbb4fb002 Mon Sep 17 00:00:00 2001
From: uyjulian <uyjulian@gmail.com>
Date: Mon, 14 Mar 2022 19:52:20 -0500
Subject: [PATCH] Add elftypechanger tool

---
 tools/Makefile                            |   8 +-
 tools/elftypechanger/Makefile             |  14 +++
 tools/elftypechanger/src/elftypechanger.c | 102 ++++++++++++++++++++++
 3 files changed, 123 insertions(+), 1 deletion(-)
 create mode 100644 tools/elftypechanger/Makefile
 create mode 100644 tools/elftypechanger/src/elftypechanger.c

diff --git a/tools/Makefile b/tools/Makefile
index 8a2884247a50..8d0e6bf16f6d 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -6,7 +6,13 @@
 # Licenced under Academic Free License version 2.0
 # Review ps2sdk README & LICENSE files for further details.
 
-SUBDIRS = bin2s bin2c bin2o adpenc ps2adpcm \
+SUBDIRS = \
+	adpenc \
+	bin2c \
+	bin2o \
+	bin2s \
+	elftypechanger \
+	ps2adpcm \
 #	  gensymtab
 
 include $(PS2SDKSRC)/Defs.make
diff --git a/tools/elftypechanger/Makefile b/tools/elftypechanger/Makefile
new file mode 100644
index 000000000000..ed23b67aea30
--- /dev/null
+++ b/tools/elftypechanger/Makefile
@@ -0,0 +1,14 @@
+# _____     ___ ____     ___ ____
+#  ____|   |    ____|   |        | |____|
+# |     ___|   |____ ___|    ____| |    \    PS2DEV Open Source Project.
+#-----------------------------------------------------------------------
+# Copyright 2001-2004, ps2dev - http://www.ps2dev.org
+# Licenced under Academic Free License version 2.0
+# Review ps2sdk README & LICENSE files for further details.
+
+TOOLS_OBJS = elftypechanger.o
+
+include $(PS2SDKSRC)/Defs.make
+include $(PS2SDKSRC)/tools/Rules.bin.make
+include $(PS2SDKSRC)/tools/Rules.make
+include $(PS2SDKSRC)/tools/Rules.release
diff --git a/tools/elftypechanger/src/elftypechanger.c b/tools/elftypechanger/src/elftypechanger.c
new file mode 100644
index 000000000000..584b78764fb3
--- /dev/null
+++ b/tools/elftypechanger/src/elftypechanger.c
@@ -0,0 +1,102 @@
+/*
+# _____     ___ ____     ___ ____
+#  ____|   |    ____|   |        | |____|
+# |     ___|   |____ ___|    ____| |    \    PS2DEV Open Source Project.
+#-----------------------------------------------------------------------
+# Copyright 2001-2022, ps2dev - http://www.ps2dev.org
+# Licenced under Academic Free License version 2.0
+# Review ps2sdk README & LICENSE files for further details.
+*/
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+
+unsigned char *buffer;
+
+int main(int argc, char *argv[])
+{
+	int fd_size;
+	FILE *source, *dest;
+	char *e_type_chr_end;
+	uint16_t e_type_int;
+
+	if (argc != 4)
+	{
+		printf("elftypechanger\n"
+			   "Usage: elftypechanger infile outfile e_type\n\n");
+		return 1;
+	}
+
+	if (argv[3][0] == '\x00')
+	{
+		printf("Argument 3 is empty.\n");
+		return 1;
+	}
+
+	e_type_chr_end = NULL;
+	e_type_int = (uint16_t)strtoul(argv[3], &e_type_chr_end, 16);
+	if (e_type_chr_end == NULL || *e_type_chr_end != '\x00')
+	{
+		printf("Argument 3 does is not a hexadecimal number.\n");
+		return 1;
+	}
+
+	if ((source = fopen(argv[1], "rb")) == NULL)
+	{
+		printf("Error opening %s for reading.\n",argv[1]);
+		return 1;
+	}
+
+	fseek(source, 0, SEEK_END);
+	fd_size = ftell(source);
+	fseek(source, 0, SEEK_SET);
+
+	buffer = malloc(fd_size);
+	if (buffer == NULL)
+	{
+		printf("Failed to allocate memory.\n");
+		fclose(source);
+		return 1;
+	}
+
+	if (fread(buffer, 1, fd_size, source) != fd_size)
+	{
+		printf("Failed to read file.\n");
+		fclose(source);
+		return 1;
+	}
+	fclose(source);
+
+	if (fd_size < 18)
+	{
+		printf("File is too small to be an ELF.\n");
+		return 1;
+	}
+
+	if (memcmp("\177ELF", buffer, 4) != 0)
+	{
+		printf("File does not appear to be ELF.\n");
+		return 1;
+	}
+
+	*((uint16_t *)(buffer + 16)) = e_type_int;
+
+	if ((dest = fopen(argv[2], "w")) == NULL)
+	{
+		printf("Failed to open/create %s.\n", argv[2]);
+		return 1;
+	}
+
+	if (fwrite(buffer, 1, fd_size, dest) != fd_size)
+	{
+		printf("Failed to write modified file.\n");
+		fclose(dest);
+		return 1;
+	}
+
+	fclose(dest);
+
+	return 0;
+}