gh-91048: Refactor _testexternalinspection and add Windows support (#132852)

1 files changed, 793 insertions, 0 deletions

diff --git a/Python/remote_debug.h b/Python/remote_debug.h
new file mode 100644
index 0000000..ba29ec5
--- /dev/null
+++ b/Python/remote_debug.h
@@ -0,0 +1,793 @@
+/*
+IMPORTANT: This header file is full of static functions that are not exported.
+
+The reason is that we don't want to export these functions to the Python API
+and they can be used both for the interpreter and some shared libraries. The
+reason we don't want to export them is to avoid having them participating in
+return-oriented programming attacks.
+
+If you need to add a new function ensure that is declared 'static'.
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_MODULE define"
+#endif
+
+#include "pyconfig.h"
+#include "internal/pycore_ceval.h"
+
+#ifdef __linux__
+#    include <elf.h>
+#    include <sys/uio.h>
+#    if INTPTR_MAX == INT64_MAX
+#        define Elf_Ehdr Elf64_Ehdr
+#        define Elf_Shdr Elf64_Shdr
+#        define Elf_Phdr Elf64_Phdr
+#    else
+#        define Elf_Ehdr Elf32_Ehdr
+#        define Elf_Shdr Elf32_Shdr
+#        define Elf_Phdr Elf32_Phdr
+#    endif
+#    include <sys/mman.h>
+#endif
+
+#if defined(__APPLE__) && TARGET_OS_OSX
+#  include <libproc.h>
+#  include <mach-o/fat.h>
+#  include <mach-o/loader.h>
+#  include <mach-o/nlist.h>
+#  include <mach/mach.h>
+#  include <mach/mach_vm.h>
+#  include <mach/machine.h>
+#  include <sys/mman.h>
+#  include <sys/proc.h>
+#  include <sys/sysctl.h>
+#endif
+
+#ifdef MS_WINDOWS
+    // Windows includes and definitions
+#include <windows.h>
+#include <psapi.h>
+#include <tlhelp32.h>
+#endif
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifndef MS_WINDOWS
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#endif
+
+#ifndef HAVE_PROCESS_VM_READV
+#    define HAVE_PROCESS_VM_READV 0
+#endif
+
+// Define a platform-independent process handle structure
+typedef struct {
+    pid_t pid;
+#ifdef MS_WINDOWS
+    HANDLE hProcess;
+#endif
+} proc_handle_t;
+
+// Initialize the process handle
+static int
+_Py_RemoteDebug_InitProcHandle(proc_handle_t *handle, pid_t pid) {
+    handle->pid = pid;
+#ifdef MS_WINDOWS
+    handle->hProcess = OpenProcess(
+        PROCESS_VM_READ | PROCESS_VM_WRITE | PROCESS_VM_OPERATION | PROCESS_QUERY_INFORMATION,
+        FALSE, pid);
+    if (handle->hProcess == NULL) {
+        PyErr_SetFromWindowsErr(0);
+        return -1;
+    }
+#endif
+    return 0;
+}
+
+// Clean up the process handle
+static void
+_Py_RemoteDebug_CleanupProcHandle(proc_handle_t *handle) {
+#ifdef MS_WINDOWS
+    if (handle->hProcess != NULL) {
+        CloseHandle(handle->hProcess);
+        handle->hProcess = NULL;
+    }
+#endif
+    handle->pid = 0;
+}
+
+#if defined(__APPLE__) && TARGET_OS_OSX
+
+static uintptr_t
+return_section_address64(
+    const char* section,
+    mach_port_t proc_ref,
+    uintptr_t base,
+    void* map
+) {
+    struct mach_header_64* hdr = (struct mach_header_64*)map;
+    int ncmds = hdr->ncmds;
+
+    int cmd_cnt = 0;
+    struct segment_command_64* cmd = map + sizeof(struct mach_header_64);
+
+    mach_vm_size_t size = 0;
+    mach_msg_type_number_t count = sizeof(vm_region_basic_info_data_64_t);
+    mach_vm_address_t address = (mach_vm_address_t)base;
+    vm_region_basic_info_data_64_t r_info;
+    mach_port_t object_name;
+    uintptr_t vmaddr = 0;
+
+    for (int i = 0; cmd_cnt < 2 && i < ncmds; i++) {
+        if (cmd->cmd == LC_SEGMENT_64 && strcmp(cmd->segname, "__TEXT") == 0) {
+            vmaddr = cmd->vmaddr;
+        }
+        if (cmd->cmd == LC_SEGMENT_64 && strcmp(cmd->segname, "__DATA") == 0) {
+            while (cmd->filesize != size) {
+                address += size;
+                kern_return_t ret = mach_vm_region(
+                    proc_ref,
+                    &address,
+                    &size,
+                    VM_REGION_BASIC_INFO_64,
+                    (vm_region_info_t)&r_info,  // cppcheck-suppress [uninitvar]
+                    &count,
+                    &object_name
+                );
+                if (ret != KERN_SUCCESS) {
+                    PyErr_SetString(
+                        PyExc_RuntimeError, "Cannot get any more VM maps.\n");
+                    return 0;
+                }
+            }
+
+            int nsects = cmd->nsects;
+            struct section_64* sec = (struct section_64*)(
+                (void*)cmd + sizeof(struct segment_command_64)
+                );
+            for (int j = 0; j < nsects; j++) {
+                if (strcmp(sec[j].sectname, section) == 0) {
+                    return base + sec[j].addr - vmaddr;
+                }
+            }
+            cmd_cnt++;
+        }
+
+        cmd = (struct segment_command_64*)((void*)cmd + cmd->cmdsize);
+    }
+
+    // We should not be here, but if we are there, we should say about this
+    PyErr_SetString(
+        PyExc_RuntimeError, "Cannot find section address.\n");
+    return 0;
+}
+
+static uintptr_t
+return_section_address32(
+    const char* section,
+    mach_port_t proc_ref,
+    uintptr_t base,
+    void* map
+) {
+    struct mach_header* hdr = (struct mach_header*)map;
+    int ncmds = hdr->ncmds;
+
+    int cmd_cnt = 0;
+    struct segment_command* cmd = map + sizeof(struct mach_header);
+
+    mach_vm_size_t size = 0;
+    mach_msg_type_number_t count = sizeof(vm_region_basic_info_data_t);
+    mach_vm_address_t address = (mach_vm_address_t)base;
+    vm_region_basic_info_data_t r_info;
+    mach_port_t object_name;
+    uintptr_t vmaddr = 0;
+
+    for (int i = 0; cmd_cnt < 2 && i < ncmds; i++) {
+        if (cmd->cmd == LC_SEGMENT && strcmp(cmd->segname, "__TEXT") == 0) {
+            vmaddr = cmd->vmaddr;
+        }
+        if (cmd->cmd == LC_SEGMENT && strcmp(cmd->segname, "__DATA") == 0) {
+            while (cmd->filesize != size) {
+                address += size;
+                kern_return_t ret = mach_vm_region(
+                    proc_ref,
+                    &address,
+                    &size,
+                    VM_REGION_BASIC_INFO,
+                    (vm_region_info_t)&r_info,  // cppcheck-suppress [uninitvar]
+                    &count,
+                    &object_name
+                );
+                if (ret != KERN_SUCCESS) {
+                    PyErr_SetString(
+                        PyExc_RuntimeError, "Cannot get any more VM maps.\n");
+                    return 0;
+                }
+            }
+
+            int nsects = cmd->nsects;
+            struct section* sec = (struct section*)(
+                (void*)cmd + sizeof(struct segment_command)
+                );
+            for (int j = 0; j < nsects; j++) {
+                if (strcmp(sec[j].sectname, section) == 0) {
+                    return base + sec[j].addr - vmaddr;
+                }
+            }
+            cmd_cnt++;
+        }
+
+        cmd = (struct segment_command*)((void*)cmd + cmd->cmdsize);
+    }
+
+    // We should not be here, but if we are there, we should say about this
+    PyErr_SetString(
+        PyExc_RuntimeError, "Cannot find section address.\n");
+    return 0;
+}
+
+static uintptr_t
+return_section_address_fat(
+    const char* section,
+    mach_port_t proc_ref,
+    uintptr_t base,
+    void* map
+) {
+    struct fat_header* fat_hdr = (struct fat_header*)map;
+
+    // Determine host CPU type for architecture selection
+    cpu_type_t cpu;
+    int is_abi64;
+    size_t cpu_size = sizeof(cpu), abi64_size = sizeof(is_abi64);
+
+    sysctlbyname("hw.cputype", &cpu, &cpu_size, NULL, 0);
+    sysctlbyname("hw.cpu64bit_capable", &is_abi64, &abi64_size, NULL, 0);
+
+    cpu |= is_abi64 * CPU_ARCH_ABI64;
+
+    // Check endianness
+    int swap = fat_hdr->magic == FAT_CIGAM;
+    struct fat_arch* arch = (struct fat_arch*)(map + sizeof(struct fat_header));
+
+    // Get number of architectures in fat binary
+    uint32_t nfat_arch = swap ? __builtin_bswap32(fat_hdr->nfat_arch) : fat_hdr->nfat_arch;
+
+    // Search for matching architecture
+    for (uint32_t i = 0; i < nfat_arch; i++) {
+        cpu_type_t arch_cpu = swap ? __builtin_bswap32(arch[i].cputype) : arch[i].cputype;
+
+        if (arch_cpu == cpu) {
+            // Found matching architecture, now process it
+            uint32_t offset = swap ? __builtin_bswap32(arch[i].offset) : arch[i].offset;
+            struct mach_header_64* hdr = (struct mach_header_64*)(map + offset);
+
+            // Determine which type of Mach-O it is and process accordingly
+            switch (hdr->magic) {
+                case MH_MAGIC:
+                case MH_CIGAM:
+                    return return_section_address32(section, proc_ref, base, (void*)hdr);
+
+                case MH_MAGIC_64:
+                case MH_CIGAM_64:
+                    return return_section_address64(section, proc_ref, base, (void*)hdr);
+
+                default:
+                    PyErr_SetString(PyExc_RuntimeError, "Unknown Mach-O magic in fat binary.\n");
+                    return 0;
+            }
+        }
+    }
+
+    PyErr_SetString(PyExc_RuntimeError, "No matching architecture found in fat binary.\n");
+    return 0;
+}
+
+static uintptr_t
+search_section_in_file(const char* secname, char* path, uintptr_t base, mach_vm_size_t size, mach_port_t proc_ref)
+{
+    int fd = open(path, O_RDONLY);
+    if (fd == -1) {
+        PyErr_Format(PyExc_RuntimeError, "Cannot open binary %s\n", path);
+        return 0;
+    }
+
+    struct stat fs;
+    if (fstat(fd, &fs) == -1) {
+        PyErr_Format(PyExc_RuntimeError, "Cannot get size of binary %s\n", path);
+        close(fd);
+        return 0;
+    }
+
+    void* map = mmap(0, fs.st_size, PROT_READ, MAP_SHARED, fd, 0);
+    if (map == MAP_FAILED) {
+        PyErr_Format(PyExc_RuntimeError, "Cannot map binary %s\n", path);
+        close(fd);
+        return 0;
+    }
+
+    uintptr_t result = 0;
+    uint32_t magic = *(uint32_t*)map;
+
+    switch (magic) {
+    case MH_MAGIC:
+    case MH_CIGAM:
+        result = return_section_address32(secname, proc_ref, base, map);
+        break;
+    case MH_MAGIC_64:
+    case MH_CIGAM_64:
+        result = return_section_address64(secname, proc_ref, base, map);
+        break;
+    case FAT_MAGIC:
+    case FAT_CIGAM:
+        result = return_section_address_fat(secname, proc_ref, base, map);
+        break;
+    default:
+        PyErr_SetString(PyExc_RuntimeError, "Unknown Mach-O magic");
+        break;
+    }
+
+    munmap(map, fs.st_size);
+    if (close(fd) != 0) {
+        PyErr_SetFromErrno(PyExc_OSError);
+    }
+    return result;
+}
+
+
+static mach_port_t
+pid_to_task(pid_t pid)
+{
+    mach_port_t task;
+    kern_return_t result;
+
+    result = task_for_pid(mach_task_self(), pid, &task);
+    if (result != KERN_SUCCESS) {
+        PyErr_Format(PyExc_PermissionError, "Cannot get task for PID %d", pid);
+        return 0;
+    }
+    return task;
+}
+
+static uintptr_t
+search_map_for_section(proc_handle_t *handle, const char* secname, const char* substr) {
+    mach_vm_address_t address = 0;
+    mach_vm_size_t size = 0;
+    mach_msg_type_number_t count = sizeof(vm_region_basic_info_data_64_t);
+    vm_region_basic_info_data_64_t region_info;
+    mach_port_t object_name;
+
+    mach_port_t proc_ref = pid_to_task(handle->pid);
+    if (proc_ref == 0) {
+        PyErr_SetString(PyExc_PermissionError, "Cannot get task for PID");
+        return 0;
+    }
+
+    int match_found = 0;
+    char map_filename[MAXPATHLEN + 1];
+    while (mach_vm_region(
+        proc_ref,
+        &address,
+        &size,
+        VM_REGION_BASIC_INFO_64,
+        (vm_region_info_t)&region_info,
+        &count,
+        &object_name) == KERN_SUCCESS)
+    {
+        if ((region_info.protection & VM_PROT_READ) == 0
+            || (region_info.protection & VM_PROT_EXECUTE) == 0) {
+            address += size;
+            continue;
+        }
+
+        int path_len = proc_regionfilename(
+            handle->pid, address, map_filename, MAXPATHLEN);
+        if (path_len == 0) {
+            address += size;
+            continue;
+        }
+
+        char* filename = strrchr(map_filename, '/');
+        if (filename != NULL) {
+            filename++;  // Move past the '/'
+        } else {
+            filename = map_filename;  // No path, use the whole string
+        }
+
+        if (!match_found && strncmp(filename, substr, strlen(substr)) == 0) {
+            match_found = 1;
+            return search_section_in_file(
+                secname, map_filename, address, size, proc_ref);
+        }
+
+        address += size;
+    }
+
+    PyErr_SetString(PyExc_RuntimeError,
+        "mach_vm_region failed to find the section");
+    return 0;
+}
+
+#endif // (__APPLE__ && TARGET_OS_OSX)
+
+#if defined(__linux__) && HAVE_PROCESS_VM_READV
+static uintptr_t
+search_elf_file_for_section(
+        proc_handle_t *handle,
+        const char* secname,
+        uintptr_t start_address,
+        const char *elf_file)
+{
+    if (start_address == 0) {
+        return 0;
+    }
+
+    uintptr_t result = 0;
+    void* file_memory = NULL;
+
+    int fd = open(elf_file, O_RDONLY);
+    if (fd < 0) {
+        PyErr_SetFromErrno(PyExc_OSError);
+        goto exit;
+    }
+
+    struct stat file_stats;
+    if (fstat(fd, &file_stats) != 0) {
+        PyErr_SetFromErrno(PyExc_OSError);
+        goto exit;
+    }
+
+    file_memory = mmap(NULL, file_stats.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+    if (file_memory == MAP_FAILED) {
+        PyErr_SetFromErrno(PyExc_OSError);
+        goto exit;
+    }
+
+    Elf_Ehdr* elf_header = (Elf_Ehdr*)file_memory;
+
+    Elf_Shdr* section_header_table = (Elf_Shdr*)(file_memory + elf_header->e_shoff);
+
+    Elf_Shdr* shstrtab_section = &section_header_table[elf_header->e_shstrndx];
+    char* shstrtab = (char*)(file_memory + shstrtab_section->sh_offset);
+
+    Elf_Shdr* section = NULL;
+    for (int i = 0; i < elf_header->e_shnum; i++) {
+        char* this_sec_name = shstrtab + section_header_table[i].sh_name;
+        // Move 1 character to account for the leading "."
+        this_sec_name += 1;
+        if (strcmp(secname, this_sec_name) == 0) {
+            section = &section_header_table[i];
+            break;
+        }
+    }
+
+    Elf_Phdr* program_header_table = (Elf_Phdr*)(file_memory + elf_header->e_phoff);
+    // Find the first PT_LOAD segment
+    Elf_Phdr* first_load_segment = NULL;
+    for (int i = 0; i < elf_header->e_phnum; i++) {
+        if (program_header_table[i].p_type == PT_LOAD) {
+            first_load_segment = &program_header_table[i];
+            break;
+        }
+    }
+
+    if (section != NULL && first_load_segment != NULL) {
+        uintptr_t elf_load_addr = first_load_segment->p_vaddr
+            - (first_load_segment->p_vaddr % first_load_segment->p_align);
+        result = start_address + (uintptr_t)section->sh_addr - elf_load_addr;
+    }
+
+exit:
+    if (file_memory != NULL) {
+        munmap(file_memory, file_stats.st_size);
+    }
+    if (fd >= 0 && close(fd) != 0) {
+        PyErr_SetFromErrno(PyExc_OSError);
+    }
+    return result;
+}
+
+static uintptr_t
+search_linux_map_for_section(proc_handle_t *handle, const char* secname, const char* substr)
+{
+    char maps_file_path[64];
+    sprintf(maps_file_path, "/proc/%d/maps", handle->pid);
+
+    FILE* maps_file = fopen(maps_file_path, "r");
+    if (maps_file == NULL) {
+        PyErr_SetFromErrno(PyExc_OSError);
+        return 0;
+    }
+
+    size_t linelen = 0;
+    size_t linesz = PATH_MAX;
+    char *line = PyMem_Malloc(linesz);
+    if (!line) {
+        fclose(maps_file);
+        PyErr_NoMemory();
+        return 0;
+    }
+
+    uintptr_t retval = 0;
+    while (fgets(line + linelen, linesz - linelen, maps_file) != NULL) {
+        linelen = strlen(line);
+        if (line[linelen - 1] != '\n') {
+            // Read a partial line: realloc and keep reading where we left off.
+            // Note that even the last line will be terminated by a newline.
+            linesz *= 2;
+            char *biggerline = PyMem_Realloc(line, linesz);
+            if (!biggerline) {
+                PyMem_Free(line);
+                fclose(maps_file);
+                PyErr_NoMemory();
+                return 0;
+            }
+            line = biggerline;
+            continue;
+        }
+
+        // Read a full line: strip the newline
+        line[linelen - 1] = '\0';
+        // and prepare to read the next line into the start of the buffer.
+        linelen = 0;
+
+        unsigned long start = 0;
+        unsigned long path_pos = 0;
+        sscanf(line, "%lx-%*x %*s %*s %*s %*s %ln", &start, &path_pos);
+
+        if (!path_pos) {
+            // Line didn't match our format string.  This shouldn't be
+            // possible, but let's be defensive and skip the line.
+            continue;
+        }
+
+        const char *path = line + path_pos;
+        const char *filename = strrchr(path, '/');
+        if (filename) {
+            filename++;  // Move past the '/'
+        } else {
+            filename = path;  // No directories, or an empty string
+        }
+
+        if (strstr(filename, substr)) {
+            retval = search_elf_file_for_section(handle, secname, start, path);
+            if (retval) {
+                break;
+            }
+        }
+    }
+
+    PyMem_Free(line);
+    fclose(maps_file);
+
+    return retval;
+}
+
+
+#endif // __linux__
+
+#ifdef MS_WINDOWS
+
+static void* analyze_pe(const wchar_t* mod_path, BYTE* remote_base, const char* secname) {
+    HANDLE hFile = CreateFileW(mod_path, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+    if (hFile == INVALID_HANDLE_VALUE) {
+        PyErr_SetFromWindowsErr(0);
+        return NULL;
+    }
+    HANDLE hMap = CreateFileMapping(hFile, NULL, PAGE_READONLY, 0, 0, 0);
+    if (!hMap) {
+        PyErr_SetFromWindowsErr(0);
+        CloseHandle(hFile);
+        return NULL;
+    }
+
+    BYTE* mapView = (BYTE*)MapViewOfFile(hMap, FILE_MAP_READ, 0, 0, 0);
+    if (!mapView) {
+        PyErr_SetFromWindowsErr(0);
+        CloseHandle(hMap);
+        CloseHandle(hFile);
+        return NULL;
+    }
+
+    IMAGE_DOS_HEADER* pDOSHeader = (IMAGE_DOS_HEADER*)mapView;
+    if (pDOSHeader->e_magic != IMAGE_DOS_SIGNATURE) {
+        PyErr_SetString(PyExc_RuntimeError, "Invalid DOS signature.");
+        UnmapViewOfFile(mapView);
+        CloseHandle(hMap);
+        CloseHandle(hFile);
+        return NULL;
+    }
+
+    IMAGE_NT_HEADERS* pNTHeaders = (IMAGE_NT_HEADERS*)(mapView + pDOSHeader->e_lfanew);
+    if (pNTHeaders->Signature != IMAGE_NT_SIGNATURE) {
+        PyErr_SetString(PyExc_RuntimeError, "Invalid NT signature.");
+        UnmapViewOfFile(mapView);
+        CloseHandle(hMap);
+        CloseHandle(hFile);
+        return NULL;
+    }
+
+    IMAGE_SECTION_HEADER* pSection_header = (IMAGE_SECTION_HEADER*)(mapView + pDOSHeader->e_lfanew + sizeof(IMAGE_NT_HEADERS));
+    void* runtime_addr = NULL;
+
+    for (int i = 0; i < pNTHeaders->FileHeader.NumberOfSections; i++) {
+        const char* name = (const char*)pSection_header[i].Name;
+        if (strncmp(name, secname, IMAGE_SIZEOF_SHORT_NAME) == 0) {
+            runtime_addr = remote_base + pSection_header[i].VirtualAddress;
+            break;
+        }
+    }
+
+    UnmapViewOfFile(mapView);
+    CloseHandle(hMap);
+    CloseHandle(hFile);
+
+    return runtime_addr;
+}
+
+
+static uintptr_t
+search_windows_map_for_section(proc_handle_t* handle, const char* secname, const wchar_t* substr) {
+    HANDLE hProcSnap;
+    do {
+        hProcSnap = CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, handle->pid);
+    } while (hProcSnap == INVALID_HANDLE_VALUE && GetLastError() == ERROR_BAD_LENGTH);
+
+    if (hProcSnap == INVALID_HANDLE_VALUE) {
+        PyErr_SetString(PyExc_PermissionError, "Unable to create module snapshot. Check permissions or PID.");
+        return 0;
+    }
+
+    MODULEENTRY32W moduleEntry;
+    moduleEntry.dwSize = sizeof(moduleEntry);
+    void* runtime_addr = NULL;
+
+    for (BOOL hasModule = Module32FirstW(hProcSnap, &moduleEntry); hasModule; hasModule = Module32NextW(hProcSnap, &moduleEntry)) {
+        // Look for either python executable or DLL
+        if (wcsstr(moduleEntry.szModule, substr)) {
+            runtime_addr = analyze_pe(moduleEntry.szExePath, moduleEntry.modBaseAddr, secname);
+            if (runtime_addr != NULL) {
+                break;
+            }
+        }
+    }
+
+    CloseHandle(hProcSnap);
+    return (uintptr_t)runtime_addr;
+}
+
+#endif // MS_WINDOWS
+
+// Get the PyRuntime section address for any platform
+static uintptr_t
+_Py_RemoteDebug_GetPyRuntimeAddress(proc_handle_t* handle)
+{
+    uintptr_t address = 0;
+
+#ifdef MS_WINDOWS
+    // On Windows, search for 'python' in executable or DLL
+    address = search_windows_map_for_section(handle, "PyRuntime", L"python");
+    if (address == 0) {
+        // Error out: 'python' substring covers both executable and DLL
+        PyErr_SetString(PyExc_RuntimeError, "Failed to find the PyRuntime section in the process.");
+    }
+#elif defined(__linux__)
+    // On Linux, search for 'python' in executable or DLL
+    address = search_linux_map_for_section(handle, "PyRuntime", "python");
+    if (address == 0) {
+        // Error out: 'python' substring covers both executable and DLL
+        PyErr_SetString(PyExc_RuntimeError, "Failed to find the PyRuntime section in the process.");
+    }
+#else
+    // On macOS, try libpython first, then fall back to python
+    address = search_map_for_section(handle, "PyRuntime", "libpython");
+    if (address == 0) {
+        // TODO: Differentiate between not found and error
+        PyErr_Clear();
+        address = search_map_for_section(handle, "PyRuntime", "python");
+    }
+#endif
+
+    return address;
+}
+
+// Platform-independent memory read function
+static int
+_Py_RemoteDebug_ReadRemoteMemory(proc_handle_t *handle, uintptr_t remote_address, size_t len, void* dst)
+{
+#ifdef MS_WINDOWS
+    SIZE_T read_bytes = 0;
+    SIZE_T result = 0;
+    do {
+        if (!ReadProcessMemory(handle->hProcess, (LPCVOID)(remote_address + result), (char*)dst + result, len - result, &read_bytes)) {
+            PyErr_SetFromWindowsErr(0);
+            return -1;
+        }
+        result += read_bytes;
+    } while (result < len);
+    return 0;
+#elif defined(__linux__) && HAVE_PROCESS_VM_READV
+    struct iovec local[1];
+    struct iovec remote[1];
+    Py_ssize_t result = 0;
+    Py_ssize_t read_bytes = 0;
+
+    do {
+        local[0].iov_base = (char*)dst + result;
+        local[0].iov_len = len - result;
+        remote[0].iov_base = (void*)(remote_address + result);
+        remote[0].iov_len = len - result;
+
+        read_bytes = process_vm_readv(handle->pid, local, 1, remote, 1, 0);
+        if (read_bytes < 0) {
+            PyErr_SetFromErrno(PyExc_OSError);
+            return -1;
+        }
+
+        result += read_bytes;
+    } while ((size_t)read_bytes != local[0].iov_len);
+    return 0;
+#elif defined(__APPLE__) && TARGET_OS_OSX
+    Py_ssize_t result = -1;
+    kern_return_t kr = mach_vm_read_overwrite(
+        pid_to_task(handle->pid),
+        (mach_vm_address_t)remote_address,
+        len,
+        (mach_vm_address_t)dst,
+        (mach_vm_size_t*)&result);
+
+    if (kr != KERN_SUCCESS) {
+        switch (kr) {
+        case KERN_PROTECTION_FAILURE:
+            PyErr_SetString(PyExc_PermissionError, "Not enough permissions to read memory");
+            break;
+        case KERN_INVALID_ARGUMENT:
+            PyErr_SetString(PyExc_PermissionError, "Invalid argument to mach_vm_read_overwrite");
+            break;
+        default:
+            PyErr_SetString(PyExc_RuntimeError, "Unknown error reading memory");
+        }
+        return -1;
+    }
+    return 0;
+#else
+    Py_UNREACHABLE();
+#endif
+}
+
+static int
+_Py_RemoteDebug_ReadDebugOffsets(
+    proc_handle_t *handle,
+    uintptr_t *runtime_start_address,
+    _Py_DebugOffsets* debug_offsets
+) {
+    *runtime_start_address = _Py_RemoteDebug_GetPyRuntimeAddress(handle);
+    if (!*runtime_start_address) {
+        if (!PyErr_Occurred()) {
+            PyErr_SetString(
+                PyExc_RuntimeError, "Failed to get PyRuntime address");
+        }
+        return -1;
+    }
+    size_t size = sizeof(struct _Py_DebugOffsets);
+    if (0 != _Py_RemoteDebug_ReadRemoteMemory(handle, *runtime_start_address, size, debug_offsets)) {
+        return -1;
+    }
+    return 0;
+}
+
+#ifdef __cplusplus
+}
+#endif
\ No newline at end of file