get_module_path_linux.cpp

#include <cstdint>
#include <charconv>
#include <iostream>
#include <fstream>
#include <regex>


void test1();


template<class T, typename U>
bool from_chars_hex(T &m, U &value) {
    std::from_chars(m.str().data(), m.str().data() + m.str().size(), value, 16);
    return (value > 0);
}


static std::string get_module_path(uintptr_t address)
{
    std::smatch m;

    /* example: 7c818e000000-7c818e028000 r--p 00000000 103:01 2776778        /usr/lib/x86_64-linux-gnu/libc.so.6 */
    const std::regex reg(
        "^"
        "([0-9a-fA-F]+)"    "-"    /* address start */
        "([0-9a-fA-F]+)"    " "    /* address end */
        "[r-][w-][x-][ps]"  " "    /* permissions */
        "[0-9a-fA-F]+"      " "    /* offset */
        "[0-9a-fA-F]+"      ":"    /* device major */
        "[0-9a-fA-F]+"      " "    /* device minor */
        "[0-9]+"            "[ ]+" /* inode */
        "(/.*)"                    /* path */
    );

    /* open maps file for reading */
    std::ifstream ifs("/proc/self/maps");

    if (!ifs.is_open()) {
        return {};
    }

    for (std::string line; std::getline(ifs, line); ) {
        if (!std::regex_match(line, m, reg) || m.size() != 4) {
            continue;
        }

        uint64_t start = 0, end = 0;

        /* check if address is within range */
        if (from_chars_hex(m[1], start) &&
            from_chars_hex(m[2], end) &&
            address > start && address < end)
        {
            return m[3].str();
        }
    }

    return {};
}


void test1()
{
    std::string path = get_module_path(reinterpret_cast<uintptr_t>(malloc));

    if (!path.empty()) {
        std::cout << path << std::endl;
    }
}


int main()
{
    test1();
    return 0;
}