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https://github.com/d0k3/GodMode9.git
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89 lines
3.5 KiB
C
89 lines
3.5 KiB
C
#include "romfs.h"
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// validate header by checking offsets and sizes
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u32 ValidateLv3Header(RomFsLv3Header* lv3, u32 max_size) {
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return ((lv3->size_header == 0x28) &&
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(lv3->offset_dirhash >= lv3->size_header) &&
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(lv3->offset_dirmeta >= lv3->offset_dirhash + lv3->size_dirhash) &&
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(lv3->offset_filehash >= lv3->offset_dirmeta + lv3->size_dirmeta) &&
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(lv3->offset_filemeta >= lv3->offset_filehash + lv3->size_filehash) &&
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(lv3->offset_filedata >= lv3->offset_filemeta + lv3->size_filemeta) &&
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(!max_size || (lv3->offset_filedata <= max_size))) ? 0 : 1;
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}
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// build index of RomFS lvl3
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u32 BuildLv3Index(RomFsLv3Index* index, u8* lv3) {
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RomFsLv3Header* hdr = (RomFsLv3Header*) lv3;
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index->header = hdr;
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index->dirhash = (u32*) (void*) (lv3 + hdr->offset_dirhash);
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index->dirmeta = lv3 + hdr->offset_dirmeta;
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index->filehash = (u32*) (void*) (lv3 + hdr->offset_filehash);
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index->filemeta = lv3 + hdr->offset_filemeta;
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index->filedata = NULL;
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index->mod_dir = (hdr->size_dirhash / sizeof(u32));
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index->mod_file = (hdr->size_filehash / sizeof(u32));
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index->size_dirmeta = hdr->size_dirmeta;
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index->size_filemeta = hdr->size_filemeta;
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return 0;
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}
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// hash lvl3 path - this is used to find the first offset in the file / dir hash table
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u32 HashLv3Path(u16* wname, u32 name_len, u32 offset_parent) {
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u32 hash = offset_parent ^ 123456789;
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for (u32 i = 0; i < name_len; i++)
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hash = ((hash>>5) | (hash<<27)) ^ wname[i];
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return hash;
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}
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RomFsLv3DirMeta* GetLv3DirMeta(const char* name, u32 offset_parent, RomFsLv3Index* index) {
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RomFsLv3DirMeta* meta;
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// wide name
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u16 wname[256];
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u32 name_len = strnlen(name, 256);
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for (name_len = 0; name[name_len]; name_len++)
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wname[name_len] = name[name_len]; // poor mans UTF-8 -> UTF-16
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// hashing, first offset
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u32 hash = HashLv3Path(wname, name_len, offset_parent);
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u32 offset = index->dirhash[hash % index->mod_dir];
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// process the hashbucket (make sure we got the correct data)
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// slim chance of endless loop with broken lvl3 here
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for (; offset < index->size_dirmeta; offset = meta->offset_samehash) {
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meta = (RomFsLv3DirMeta*) (index->dirmeta + offset);
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if ((offset_parent == meta->offset_parent) &&
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(name_len == meta->name_len / 2) &&
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(memcmp(wname, meta->wname, name_len * 2) == 0))
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break;
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}
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return (offset >= index->size_dirmeta) ? NULL : meta;
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}
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RomFsLv3FileMeta* GetLv3FileMeta(const char* name, u32 offset_parent, RomFsLv3Index* index) {
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RomFsLv3FileMeta* meta;
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// wide name
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u16 wname[256];
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u32 name_len = strnlen(name, 256);
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for (name_len = 0; name[name_len]; name_len++)
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wname[name_len] = name[name_len]; // poor mans UTF-8 -> UTF-16
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// hashing, first offset
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u32 hash = HashLv3Path(wname, name_len, offset_parent);
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u32 offset = index->filehash[hash % index->mod_file];
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// process the hashbucket (make sure we got the correct data)
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// slim chance of endless loop with broken lvl3 here
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for (; offset < index->size_filemeta; offset = meta->offset_samehash) {
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meta = (RomFsLv3FileMeta*) (index->filemeta + offset);
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if ((offset_parent == meta->offset_parent) &&
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(name_len == meta->name_len / 2) &&
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(memcmp(wname, meta->wname, name_len * 2) == 0))
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break;
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}
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return (offset >= index->size_filemeta) ? NULL : meta;
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}
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