make ioplib an independent library

Author: israpps

iop/Makefile

@@ -24,7 +24,8 @@ SUBDIRS = \
 	startup \
 	system \
 	tcpip \
-	usb
+	usb \
+	utilities
 
 include $(PS2SDKSRC)/Defs.make
 include $(PS2SDKSRC)/Rules.make

iop/utilities/Makefile

@@ -0,0 +1,12 @@
+# _____     ___ ____     ___ ____
+#  ____|   |    ____|   |        | |____|
+# |     ___|   |____ ___|    ____| |    \    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.
+
+SUBDIRS = modhook
+
+include $(PS2SDKSRC)/Defs.make
+include $(PS2SDKSRC)/Rules.make

iop/utilities/modhook/Makefile

@@ -0,0 +1,15 @@
+# _____     ___ ____     ___ ____
+#  ____|   |    ____|   |        | |____|
+# |     ___|   |____ ___|    ____| |    \    PS2DEV Open Source Project.
+#-----------------------------------------------------------------------
+# Copyright 2001-2024, ps2dev - http://www.ps2dev.org
+# Licenced under Academic Free License version 2.0
+# Review ps2sdk README & LICENSE files for further details.
+
+IOP_OBJS = ioplib.o
+IOP_LIB = libmodhook.a
+
+include $(PS2SDKSRC)/Defs.make
+include $(PS2SDKSRC)/iop/Rules.lib.make
+include $(PS2SDKSRC)/iop/Rules.make
+include $(PS2SDKSRC)/iop/Rules.release

iop/utilities/modhook/include/ioplib.h

@@ -0,0 +1,36 @@
+#ifndef IOPLIB_H
+#define IOPLIB_H
+
+#include <loadcore.h>
+
+/**
+ * @file ioplib.c
+ * @brief IOP module manipulation library for hooking exports.
+ * @note depends on: `CpuSuspendIntr` `CpuResumeIntr` `GetLoadcoreInternalData`
+ */
+
+/**
+ * @brief returns an iop library pointer for the specified IRX module
+ * @returns NULL on error, else, a pointer to the struct
+ */
+iop_library_t *ioplib_getByName(const char *name);
+
+/**
+ * @brief returns the size of the export table for the specified module
+ * @param lib the library to obtain the export table size
+ * @returns the ammount of exports registered for that module
+ */
+unsigned int ioplib_getTableSize(iop_library_t *lib);
+
+/**
+ * @brief replaces the function called as a module export
+ * @param lib The iop_library_t struct of the module to modify
+ * @param entry the export number to be modified
+ * @param func the function to replace the export with
+ * @returns a pointer to the original function
+ */
+void *ioplib_hookExportEntry(iop_library_t *lib, unsigned int entry, void *func);
+void ioplib_relinkExports(iop_library_t *lib);
+
+
+#endif

iop/utilities/modhook/src/ioplib.c

@@ -0,0 +1,82 @@
+#include "ioplib.h"
+#include <intrman.h>
+#include <stdint.h>
+
+iop_library_t *ioplib_getByName(const char *name)
+{
+    iop_library_t *libptr;
+    int i;
+
+    // Get first loaded library
+    libptr = GetLoadcoreInternalData()->let_next;
+    // Loop through all loaded libraries
+    while (libptr != NULL) {
+        // Compare library name only
+        for (i = 0; i < 8; i++) {
+            if (libptr->name[i] != name[i])
+                break;
+        }
+
+        // Return if match
+        if (i == 8)
+            return libptr;
+
+        // Next library
+        libptr = libptr->prev;
+    }
+
+    return NULL;
+}
+
+unsigned int ioplib_getTableSize(iop_library_t *lib)
+{
+    void **exp;
+    unsigned int size;
+
+    exp = NULL;
+    if (lib != NULL) {
+        exp = lib->exports;
+    }
+    size = 0;
+
+    if (exp != NULL)
+        while (*exp++ != NULL)
+            size++;
+
+    return size;
+}
+
+void *ioplib_hookExportEntry(iop_library_t *lib, unsigned int entry, void *func)
+{
+    if (entry < ioplib_getTableSize(lib)) {
+        int oldstate;
+        void **exp, *temp;
+
+        exp = &lib->exports[entry];
+
+        CpuSuspendIntr(&oldstate);
+        temp = *exp;
+        *exp = func;
+        func = temp;
+        CpuResumeIntr(oldstate);
+
+        return func;
+    }
+
+    return NULL;
+}
+
+void ioplib_relinkExports(iop_library_t *lib)
+{
+    struct irx_import_table *table;
+    struct irx_import_stub *stub;
+
+    // go through each table that imports the library
+    for (table = lib->caller; table != NULL; table = table->next) {
+        // go through each import in the table
+        for (stub = (struct irx_import_stub *)table->stubs; stub->jump != 0; stub++) {
+            // patch the stub to jump to the address specified in the library export table for "fno"
+            stub->jump = 0x08000000 | (((uint32_t)lib->exports[stub->fno] << 4) >> 6);
+        }
+    }
+}