debugged patch_strtab

4 files changed, 22 insertions, 38 deletions

diff --git a/tools/patch_strtab/.gitignore b/tools/patch_strtab/.gitignore
new file mode 100644
index 0000000..1ed8234
--- /dev/null
+++ b/tools/patch_strtab/.gitignore
@@ -0,0 +1,2 @@
+patch_strtab

+*.exe

diff --git a/tools/patch_strtab/README.md b/tools/patch_strtab/README.md
new file mode 100644
index 0000000..6904ac1
--- /dev/null
+++ b/tools/patch_strtab/README.md
@@ -0,0 +1,13 @@
+README:

+

+The program patches the .strtab section of an ELF relocatable module

+by replacing certain escape sequences with the characters they represent.

+

+CodeWarrior's C++ name mangling scheme may produce linkage names that

+are not valid identifiers in the .s files provided to the 

+assembler, so we cannot use the mangled names directly as labels in the .s file.

+Still, we would like to be able to link with compiled C++ modules and add accurate symbols to them 

+before they have been decompiled. To deal with this issue, for each .s file

+we replace any illegal characters in the mangled name with valid escape sequences, 

+assemble the .s file, then use this program to postprocess the .o object code, which restores

+the correct symbol name.

diff --git a/tools/patch_strtab/patch_strtab b/tools/patch_strtab/patch_strtab
deleted file mode 100644
index 19171af..0000000
--- a/tools/patch_strtab/patch_strtab
+++ /dev/null
diff --git a/tools/patch_strtab/patch_strtab.c b/tools/patch_strtab/patch_strtab.c
index a1a947f..ee0076a 100644
--- a/tools/patch_strtab/patch_strtab.c
+++ b/tools/patch_strtab/patch_strtab.c
@@ -1,42 +1,7 @@
 /*

+patch_strtab

 

-README:

-

-The program patches the .strtab section of an ELF relocatable module

-by replacing certain escape sequences with the characters they represent.

-

-CodeWarrior's C++ name mangling scheme may produce linkage names that

-are not valid identifiers in the .s files provided to the 

-assembler, so we cannot use the mangled names directly as labels in the .s file.

-This interferes with our workflow because we would like

-to be able to link with compiled C++ modules and add accurate symbols to them 

-before they have been decompiled. To deal with this issue, for each .s file

-we replace any illegal characters in the mangled name with valid escape sequences, 

-assemble the .s file, then postprocess the .o object code with this program to restore

-the correct symbol name.

-

-*/

-

-/*

-

-Receive the .o filename in argv

-Open (rb+), load, and validate the ELF file, then fix the endianness

-  of the ELF header, section headers, and symbol tables

-  

-load the symbol table and the string table into separate buffers.

-Use sh_size to get the sizes, and record the size of the .strtab 

-

-For each symbol, follow the st_name offset into the .strtab section and read in the

-string. Get the length of the string as well

-

-replace each instance of the pre-defined escape sequences with their associated

-characters. 

-

-Write the string table back into the ELF .strtab at the same offset it was found.

-Use fseek(fp, offset, SEEK_SET), then fwrite(strTab, 1, strTabSz, fp)

-

-Since any transformation will always shorten the string, just fill in the 

-gap created at the end of the buffer with NUL bytes.

+by Max Parisi, 2020

 

 */

 

@@ -364,6 +329,10 @@ ElfStruct *LoadElfFile(char *path)
 			}

 		}

 	}

+    

+    // Fix endianness in symbol table

+    SwapSymbolTable(elf);

+    

 	return elf;

 }

 

@@ -428,7 +397,7 @@ int main(int argc, char *argv[])
         free(elf);

         return EXIT_FAILURE;

     }

-

+        

     const u32 numSyms = GetNumberOfSymbols(elf);

     for (u32 i = 0; i < numSyms; i++) {

         Elf32_Sym *sym = GetSymbol(elf, i);