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LM_FindSymbolAddress

Finds the address of a symbol within a module.

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Signature

LM_API lm_address_t LM_CALL
LM_FindSymbolAddress(const lm_module_t *module,
                     lm_string_t        symbol_name);

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Parameters

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module
const lm_module_t*
required
The module where the symbol will be looked up from.
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symbol_name
lm_string_t
required
The name of the symbol to look up.

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Return Value

Returns the address of the symbol, or LM_ADDRESS_BAD if it fails.

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Description

This function searches for a symbol by name within a specified module and returns its memory address. Symbols can represent functions, variables, or other exported identifiers within a module.

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Example

#include <libmem/libmem.h>
#include <stdio.h>

void hk_take_damage(int amount)
{
    printf("hooked take_damage! no damage will be taken\n");
    return;
}

int main()
{
    lm_module_t game_mod;
    lm_address_t fn_take_damage;

    LM_FindModule("game.dll", &game_mod);
    printf("[*] Base address of 'game.dll': %p\n", (void *)game_mod.base);

    fn_take_damage = LM_FindSymbolAddress(&game_mod, "take_damage");
    printf("[*] Found 'take_damage' function: %p\n", (void *)fn_take_damage);

    LM_HookCode(fn_take_damage, (lm_address_t)hk_take_damage, LM_NULLPTR);
    printf("[*] 'take_damage' hooked, player will no longer receive damage\n");

    return 0;
}

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Common Use Cases

  • Finding function addresses for hooking
  • Locating exported functions in DLLs or shared libraries
  • Getting addresses of global variables
  • Resolving API entry points

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Error Handling

lm_address_t symbol_addr = LM_FindSymbolAddress(&module, "my_function");
if (symbol_addr == LM_ADDRESS_BAD) {
    printf("Failed to find symbol\n");
    return 1;
}

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LM_FindSymbolAddressDemangled

Finds the address of a demangled symbol within a module.

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Signature

LM_API lm_address_t LM_CALL
LM_FindSymbolAddressDemangled(const lm_module_t *module,
                              lm_string_t        symbol_name);

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Parameters

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module
const lm_module_t*
required
The module where the symbol will be looked up from.
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symbol_name
lm_string_t
required
The demangled name of the symbol to look up (e.g., "MyClass::myMethod()").

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Return Value

Returns the address of the symbol, or LM_ADDRESS_BAD if it fails.

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Description

This function searches for a symbol using its demangled (human-readable) name and returns its memory address. This is particularly useful when working with C++ binaries where you want to search using the readable function signature instead of the mangled name.

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Example

#include <libmem/libmem.h>
#include <stdio.h>

int main()
{
    lm_module_t cpp_lib;
    lm_address_t method_addr;

    // Find a C++ library
    if (!LM_FindModule("game_engine.so", &cpp_lib)) {
        printf("Failed to find module\n");
        return 1;
    }

    // Find a C++ method using demangled name
    method_addr = LM_FindSymbolAddressDemangled(&cpp_lib, "Player::takeDamage(int)");
    
    if (method_addr == LM_ADDRESS_BAD) {
        printf("Failed to find symbol\n");
        return 1;
    }

    printf("[*] Found 'Player::takeDamage(int)' at: %p\n", (void *)method_addr);

    return 0;
}

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Notes

  • This function is specifically designed for C++ symbols where names are mangled by the compiler.
  • You can provide the human-readable function signature (e.g., "ClassName::methodName(int, char*)") instead of the mangled name.
  • The function internally demangles all symbols in the module to find a match.
  • This may be slower than LM_FindSymbolAddress if you already know the mangled name.
  • If the symbol cannot be found or demangled, LM_ADDRESS_BAD is returned.

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Comparison with LM_FindSymbolAddress

FunctionInput Name FormatUse Case
LM_FindSymbolAddressMangled name (e.g., _ZN6Player10takeDamageEi)When you know the exact mangled symbol name
LM_FindSymbolAddressDemangledDemangled name (e.g., Player::takeDamage(int))When you want to use readable C++ signatures

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