LayeredFS
This commit is contained in:
Aurora Wright
@@ -1,80 +1,107 @@
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; Code from delebile
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.arm.little
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.create "build/romfsredir.bin", 0
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.macro addr, reg, func
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add reg, pc, #func-.-8
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.endmacro
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.macro load, reg, func
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ldr reg, [pc, #func-.-8]
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.endmacro
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.macro svc, svcnum
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.word 0xef000000 + svcnum
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.endmacro
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; Patch by delebile
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.arm
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; fsOpenFileDirectly function will be redirected here.
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; If the requested archive is not ROMFS, we'll return
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; to the original function.
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openFileDirectlyHook:
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cmp r3, #3
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beq openRomfs
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load r12, fsOpenFileDirectly
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nop ; Will be replaced with the original function opcode
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bx r12
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_start:
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; We redirect ROMFS file opening by changing the parameters and call
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; the fsOpenFileDirectly function recursively. The parameter format:
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; r0 : fsUserHandle
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; r1 : Output FileHandle
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; r2 : Transaction (usually 0)
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; r3 : Archive ID
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; [sp, #0x00] : Archive PathType
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; [sp, #0x04] : Archive DataPointer
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; [sp, #0x08] : Archive PathSize
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; [sp, #0x0C] : File PathType
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; [sp, #0x10] : File DataPointer
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; [sp, #0x14] : File PathSize
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; [sp, #0x18] : File OpenFlags
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; [sp, #0x1C] : Attributes (usually 0)
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openRomfs:
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sub sp, sp, #0x50
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stmfd sp!, {r0, r1, lr}
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add sp, sp, #0x5C
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str r3, [sp, #0x0C] ; File PathType (ASCII = 3)
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load r12, romfsFileName
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str r12, [sp, #0x10] ; File DataPointer
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load r12, romfsFileNameSize
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str r12, [sp, #0x14] ; File PathSize
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load r3, archive
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bl openFileDirectlyHook
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sub sp, sp, #0x5C
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ldmfd sp!, {r0, r1, lr}
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add sp, sp, #0x50
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mov r0, r1 ; Substitute fsUserHandle with the fileHandle
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; Jumps here before the fsOpenFileDirectly call
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_mountSd:
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b mountSd
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.word 0xdead0000 ; Substituted opcode
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.word 0xdead0001 ; Branch to hooked function
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; Once we have the sd romfs file opened, we'll open a subfile
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; in order to skip the useless data.
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stmfd sp!, {r1, r3-r11}
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mrc p15, 0, r4, c13, c0, 3
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add r4, r4, #0x80
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mov r1, r4
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add r3, pc, #fsOpenSubFileCmd-.-8
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ldmia r3!, {r5-r9}
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stmia r1!, {r5-r9}
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ldr r0, [r0]
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swi 0x32
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ldr r0, [r4, #0x0C]
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ldmfd sp!, {r1, r3-r11}
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str r0, [r1]
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mov r0, #0
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bx lr
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; Jumps here before every iFileOpen call
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_fsRedir:
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b fsRedir
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.word 0xdead0002 ; Substituted opcode
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.word 0xdead0003 ; Branch to hooked function
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; Mounts SDMC and registers the archive as 'sdmc:'
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mountSd:
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cmp r3, #3
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bne _mountSd+4
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stmfd sp!, {r0-r4, lr}
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sub sp, sp, #4
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mov r1, #9
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mov r0, sp
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load r4, fsMountArchive
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blx r4
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mov r3, #0
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mov r2, #0
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ldr r1, [sp]
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addr r0, sdmcArchiveName
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load r4, fsRegisterArchive
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blx r4
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add sp, sp, #4
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ldmfd sp!, {r0-r4, lr}
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b _mountSd+4
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; Check the path passed to iFileOpen.
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; If it is trying to access a RomFS file, we try to
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; open it from the title folder on the sdcard.
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; If the file cannot be opened from the sdcard, we just open
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; it from its original archive like nothing happened
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fsRedir:
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stmfd sp!, {r0-r12, lr}
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ldrb r12, [r1]
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cmp r12, #0x72 ; 'r', should include "rom:" and "rom2:"
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bne endRedir
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sub sp, sp, #0x400
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pathRedir:
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stmfd sp!, {r0-r3}
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add r0, sp, #0x10
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addr r3, sdmcCustomPath
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pathRedir_1:
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ldrb r2, [r3], #1
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strh r2, [r0], #2
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cmp r2, #0
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bne pathRedir_1
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sub r0, r0, #2
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pathRedir_2:
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ldrh r2, [r1], #2
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cmp r2, #0x3A ; ':'
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bne pathRedir_2
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pathRedir_3:
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ldrh r2, [r1], #2
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strh r2, [r0], #2
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cmp r2, #0
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bne pathRedir_3
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ldmfd sp!, {r0-r3}
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mov r1, sp
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bl _fsRedir+4
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add sp, sp, #0x400
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cmp r0, #0
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endRedir:
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ldmfd sp!, {r0-r12, lr}
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moveq r0, #0
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beq panic
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bxeq lr
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b _fsRedir+4
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panic:
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swi 0x3C
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b panic
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.pool
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.align 4
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; Part of these symbols will be set from outside
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fsOpenFileDirectly : .word 0
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fsOpenSubFileCmd : .word 0x08010100
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.word 0 ; File Offset
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.word 0
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.word 0 ; File Size
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.word 0
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archive : .word 0
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romfsFileNameSize : .word 0
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romfsFileName : .word 0 ; File DataPointer
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.close
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sdmcArchiveName : .dcb "sdmc:", 0
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.align 4
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fsMountArchive : .word 0xdead0005
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fsRegisterArchive : .word 0xdead0006
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sdmcCustomPath : .word 0xdead0004
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.close
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