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_am: add search for OS main menu function

This commit is contained in:
Lephenixnoir 2023-08-20 18:52:34 +02:00
parent 0f23fec85d
commit 12e6cd45a4
Signed by: Lephenixnoir
GPG Key ID: 1BBA026E13FC0495
1 changed files with 110 additions and 0 deletions
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110
shell/a.cpp
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@ -142,6 +142,103 @@ void _ads(Session &session)
ad_disassemble_all(space, addresses, true);
}
//---
// am
//---
static void _am_cg_main_menu_function(VirtualSpace &vspace)
{
OS *os = vspace.os_analysis();
if(!os) {
FxOS_log(ERR, "no OS analysis");
return;
}
if(os->syscall_count() < 0x1e58) {
FxOS_log(ERR, "less than 0x1e58 syscalls");
return;
}
uint32_t sc_addr = os->syscall(0x1e58);
fmt::print("syscall %%1e58 found at 0x{:08x}\n", sc_addr);
/* Check up to 150 instructions to find the call to the internal function
SaveAndOpenMainMenu(). This call is in a widget of the shape
mov.l GetkeyToMainFunctionReturnFlag, rX
mov #3, rY
bsr SaveAndOpenMainMenu
mov.b rY, @rX
bra <start of widget>
nop */
for(int i = 0; i < 150; i++) {
uint16_t i0 = vspace.read_u16(sc_addr + 2 * (i + 0));
uint16_t i1 = vspace.read_u16(sc_addr + 2 * (i + 1));
uint16_t i2 = vspace.read_u16(sc_addr + 2 * (i + 2));
uint16_t i3 = vspace.read_u16(sc_addr + 2 * (i + 3));
uint16_t i4 = vspace.read_u16(sc_addr + 2 * (i + 4));
uint16_t i5 = vspace.read_u16(sc_addr + 2 * (i + 5));
/* Match: mov.l @(disp, pc), rX */
if((i0 & 0xf000) != 0xd000)
continue;
int rX = (i0 >> 8) & 0x0f;
/* Match: mov #3, rY */
if((i1 & 0xf0ff) != 0xe003)
continue;
int rY = (i1 >> 8) & 0x0f;
/* Match: bsr @(disp, pc) */
if((i2 & 0xf000) != 0xb000)
continue;
int disp = (i2 & 0x0fff);
/* Match: mov.b rX, @rY */
if((i3 != 0x2000 + (rX << 8) + (rY << 4)))
continue;
/* Match: bra @(_, pc) */
if((i4 & 0xf000) != 0xa000)
continue;
/* Match: nop */
if(i5 != 0x0009)
continue;
/* Return the target of the bsr instruction */
uint32_t fun_addr = sc_addr + 2*(i+2) + 4 + disp * 2;
fmt::print("found widget at 0x{:08x}\n", sc_addr + 2 * i);
fmt::print("rX = r{}, rY = r{}, disp = {}\n", rX, rY, disp);
fmt::print("main menu function address: 0x{:08x}\n", fun_addr);
}
}
static std::string parse_am(Session &session, Parser &parser)
{
if(!session.current_space)
return "";
std::string name = parser.symbol();
parser.end();
return name;
}
void _am(Session &session, std::string name)
{
if(!session.current_space) {
FxOS_log(ERR, "am: no virtual space");
return;
}
if(name == "cg_main_menu_function")
_am_cg_main_menu_function(*session.current_space);
else
FxOS_log(ERR, "am: unknown misc. command '%s'", name);
}
//---
// Command definitions
//---
@ -174,3 +271,16 @@ Disassembles all syscalls entries using ad, which stores the results in the
current virtual space's main disassembly. Unlike ad, this commands continues
even if some syscalls fail to disassemble.
)");
static ShellCommand _am_cmd(
"am",
[](Session &s, Parser &p) {
auto name = parse_am(s, p);
_am(s, name);
},
[](Session &s, Parser &p) { parse_am(s, p); },
"Analysis: Misc functions", R"(
am <name>
Runs miscellaneous analysis functions; commonly used for prototyping.
)");