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dyld_decache: made the UUID printing work for 64-bit cache files too #15

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dyld_decache: made the UUID printing work for 64-bit cache files too #15

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79 changes: 50 additions & 29 deletions dyld_decache.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -122,6 +122,12 @@ struct load_command {
uint32_t cmdsize;
};

struct load_command64 {
uint32_t pad0; // dunno what this is - it's often zero, but also often not!
uint32_t cmd;
uint32_t cmdsize;
};

#define LC_REQ_DYLD 0x80000000

#define LC_SEGMENT 0x1
Expand Down Expand Up @@ -352,22 +358,11 @@ struct category_t {
};

struct uuid_command : load_command {
uint8_t byte0;
uint8_t byte1;
uint8_t byte2;
uint8_t byte3;
uint8_t byte4;
uint8_t byte5;
uint8_t byte6;
uint8_t byte7;
uint8_t byte8;
uint8_t byte9;
uint8_t byte10;
uint8_t byte11;
uint8_t byte12;
uint8_t byte13;
uint8_t byte14;
uint8_t byte15;
uint8_t bytes[16];
};

struct uuid_command64 : load_command64 {
uint8_t bytes[16];
};

#define BIND_OPCODE_MASK 0xF0
Expand Down Expand Up @@ -438,8 +433,6 @@ class ExtraStringRepository {

boost::unordered_map<const char*, int> _indices;
std::vector<Entry> _entries;
size_t _total_size;

section _template;

public:
Expand Down Expand Up @@ -614,6 +607,18 @@ class MachOFile {
}
}

template <typename T>
void foreach_command64(void(T::*action)(const load_command64* cmd)) {
const unsigned char* cur_cmd = reinterpret_cast<const unsigned char*>(_header + 1);

for (uint32_t i = 0; i < _header->ncmds; ++ i) {
const load_command64* cmd = reinterpret_cast<const load_command64*>(cur_cmd);
cur_cmd += cmd->cmdsize;

(static_cast<T*>(this)->*action)(cmd);
}
}

// Convert VM address to file offset of the decached file _before_ inserting
// the extra sections.
long from_vmaddr(uint32_t vmaddr) const {
Expand All @@ -627,6 +632,8 @@ class MachOFile {
private:
void retrieve_segments_and_libords(const load_command* cmd);
void retrieve_uuid(const load_command* cmd);
void retrieve_uuid64(const load_command64* cmd);
void set_uuid(const uint8_t* bytes);

public:
// Checks if the VM address is included in the decached file _before_
Expand Down Expand Up @@ -654,10 +661,10 @@ class MachOFile {

void find_uuid()
{
if (_header->magic != 0xfeedface)
return;

this->foreach_command(&MachOFile::retrieve_uuid);
if (_header->magic == 0xfeedface)
this->foreach_command(&MachOFile::retrieve_uuid);
else if (_header->magic == 0xfeedfacf)
this->foreach_command64(&MachOFile::retrieve_uuid64);
}

const mach_header* header() const { return _header; }
Expand Down Expand Up @@ -1350,17 +1357,31 @@ void MachOFile::retrieve_uuid(const load_command* cmd) {
break;
case LC_UUID:
const uuid_command* uuidcmd = static_cast<const uuid_command*>(cmd);
char uuid[37];
sprintf(uuid, "%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
uuidcmd->byte0, uuidcmd->byte1, uuidcmd->byte2, uuidcmd->byte3,
uuidcmd->byte4, uuidcmd->byte5, uuidcmd->byte6, uuidcmd->byte7,
uuidcmd->byte8, uuidcmd->byte9, uuidcmd->byte10, uuidcmd->byte11,
uuidcmd->byte12, uuidcmd->byte13, uuidcmd->byte14, uuidcmd->byte15);
_uuid = uuid;
set_uuid(uuidcmd->bytes);
break;
}
}

void MachOFile::retrieve_uuid64(const load_command64* cmd) {
switch (cmd->cmd) {
default:
break;
case LC_UUID:
const uuid_command64* uuidcmd = static_cast<const uuid_command64*>(cmd);
set_uuid(uuidcmd->bytes);
break;
}
}

void MachOFile::set_uuid(const uint8_t* bytes)
{
char uuid[37];
sprintf(uuid, "%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
bytes[0], bytes[1], bytes[2], bytes[3], bytes[4], bytes[5], bytes[6], bytes[7],
bytes[8], bytes[9], bytes[10], bytes[11], bytes[12], bytes[13], bytes[14], bytes[15]);
_uuid = uuid;
}

void DecachingFile::write_segment_content(const segment_command* segcmd) {
if (!streq(segcmd->segname, "__LINKEDIT")) {
ExtraStringRepository* repo = this->repo_for_segname(segcmd->segname);
Expand Down