dr_get_mcontext x64 issue

[wooddii]

Hello, the problem is getting the value of the esp register. My Code fragment: ... dr_mcontext_t mc = { sizeof(mc),DR_MC_ALL }; dr_get_mcontext(dr_get_current_drcontext(), &mc); dr_messagebox("Top of stack is "PFX"\n", mc.xsp); ... This works fine when compiling in x86 mode, however, when compiled in x64 mode, the mc.xsp value is always zero. The same thing when compiling and running the instrcalls example. Is this a DR error or have I missed something?

[derekbruening]

Where is this code executed? A clean call? A particular event callback?

What is the return value of dr_get_mcontext?

[wooddii]

Full code below:

#define SHOW_SYMBOLS
#include "dr_api.h"
#include "drmgr.h"
#ifdef SHOW_SYMBOLS
# include "drsyms.h"
#endif
#include "utils.h"

static void event_exit(void);
static void event_thread_init(void *drcontext);
static void event_thread_exit(void *drcontext);
static dr_emit_flags_t event_app_instruction(void *drcontext, void *tag,
    instrlist_t *bb, instr_t *instr,
    bool for_trace, bool translating,
    void *user_data);
static int tls_idx;

static client_id_t my_id;

DR_EXPORT void
dr_client_main(client_id_t id, int argc, const char *argv[])
{
    dr_set_client_name("DynamoRIO Sample Client 'instrcalls'",
        "http://dynamorio.org/issues");
    drmgr_init();
    my_id = id;
    /* make it easy to tell, by looking at log file, which client executed */
    dr_log(NULL, LOG_ALL, 1, "Client 'instrcalls' initializing\n");
    /* also give notification to stderr */
#ifdef SHOW_RESULTS
    if (dr_is_notify_on()) {
# ifdef WINDOWS
        /* ask for best-effort printing to cmd window.  must be called at init. */
        dr_enable_console_printing();
# endif
        dr_fprintf(STDERR, "Client instrcalls is running\n");
    }
#endif
    dr_register_exit_event(event_exit);
    drmgr_register_bb_instrumentation_event(NULL, event_app_instruction, NULL);
    drmgr_register_thread_init_event(event_thread_init);
    drmgr_register_thread_exit_event(event_thread_exit);
#ifdef SHOW_SYMBOLS
    if (drsym_init(0) != DRSYM_SUCCESS) {
        dr_log(NULL, LOG_ALL, 1, "WARNING: unable to initialize symbol translation\n");
    }
#endif
    tls_idx = drmgr_register_tls_field();
    DR_ASSERT(tls_idx > -1);
}

static void
event_exit(void)
{
#ifdef SHOW_SYMBOLS
    if (drsym_exit() != DRSYM_SUCCESS) {
        dr_log(NULL, LOG_ALL, 1, "WARNING: error cleaning up symbol library\n");
    }
#endif
    drmgr_unregister_tls_field(tls_idx);
    drmgr_exit();
}

#ifdef WINDOWS
# define IF_WINDOWS(x) x
#else
# define IF_WINDOWS(x) /* nothing */
#endif

static void
event_thread_init(void *drcontext)
{
    file_t f;
    /* We're going to dump our data to a per-thread file.
    * On Windows we need an absolute path so we place it in
    * the same directory as our library. We could also pass
    * in a path as a client argument.
    */
    f = log_file_open(my_id, drcontext, NULL /* client lib path */,
        "instrcalls",
#ifndef WINDOWS
        DR_FILE_CLOSE_ON_FORK |
#endif
        DR_FILE_ALLOW_LARGE);
    DR_ASSERT(f != INVALID_FILE);

    /* store it in the slot provided in the drcontext */
    drmgr_set_tls_field(drcontext, tls_idx, (void *)(ptr_uint_t)f);
}

static void
event_thread_exit(void *drcontext)
{
    log_file_close((file_t)(ptr_uint_t)drmgr_get_tls_field(drcontext, tls_idx));
}

#ifdef SHOW_SYMBOLS
# define MAX_SYM_RESULT 256
static void
print_address(file_t f, app_pc addr, const char *prefix)
{
    drsym_error_t symres;
    drsym_info_t sym;
    char name[MAX_SYM_RESULT];
    char file[MAXIMUM_PATH];
    module_data_t *data;
    data = dr_lookup_module(addr);
    if (data == NULL) {
        dr_fprintf(f, "%s "PFX" ? ??:0\n", prefix, addr);
        return;
    }
    sym.struct_size = sizeof(sym);
    sym.name = name;
    sym.name_size = MAX_SYM_RESULT;
    sym.file = file;
    sym.file_size = MAXIMUM_PATH;
    symres = drsym_lookup_address(data->full_path, addr - data->start, &sym,
        DRSYM_DEFAULT_FLAGS);
    if (symres == DRSYM_SUCCESS || symres == DRSYM_ERROR_LINE_NOT_AVAILABLE) {
        const char *modname = dr_module_preferred_name(data);
        if (modname == NULL)
            modname = "<noname>";
        dr_fprintf(f, "%s "PFX" %s!%s+"PIFX, prefix, addr,
            modname, sym.name, addr - data->start - sym.start_offs);
        if (symres == DRSYM_ERROR_LINE_NOT_AVAILABLE) {
            dr_fprintf(f, " ??:0\n");
        }
        else {
            dr_fprintf(f, " %s:%"UINT64_FORMAT_CODE"+"PIFX"\n",
                sym.file, sym.line, sym.line_offs);
        }
    }
    else
        dr_fprintf(f, "%s "PFX" ? ??:0\n", prefix, addr);
    dr_free_module_data(data);
}
#endif

static void
at_call(app_pc instr_addr, app_pc target_addr)
{
    file_t f = (file_t)(ptr_uint_t)
        drmgr_get_tls_field(dr_get_current_drcontext(), tls_idx);

    dr_mcontext_t mc = { sizeof(mc),DR_MC_ALL/*only need xsp*/ };
    bool ret = dr_get_mcontext(dr_get_current_drcontext(), &mc);

    // ret is 0
    dr_messagebox("Ret is: %d", ret);
    // mc.xsp is 0
    dr_messagebox("Top of stack is "PFX"\n", mc.xsp);

#ifdef SHOW_SYMBOLS
    print_address(f, instr_addr, "CALL @ ");
    print_address(f, target_addr, "\t to ");
    dr_fprintf(f, "\tTOS is "PFX"\n", mc.xsp);
#else
    dr_fprintf(f, "CALL @ "PFX" to "PFX", TOS is "PFX"\n",
        instr_addr, target_addr, mc.xsp);
#endif
}

static void
at_call_ind(app_pc instr_addr, app_pc target_addr)
{
    file_t f = (file_t)(ptr_uint_t)
        drmgr_get_tls_field(dr_get_current_drcontext(), tls_idx);
#ifdef SHOW_SYMBOLS
    print_address(f, instr_addr, "CALL INDIRECT @ ");
    print_address(f, target_addr, "\t to ");
#else
    dr_fprintf(f, "CALL INDIRECT @ "PFX" to "PFX"\n", instr_addr, target_addr);
#endif
}

static void
at_return(app_pc instr_addr, app_pc target_addr)
{
    file_t f = (file_t)(ptr_uint_t)
        drmgr_get_tls_field(dr_get_current_drcontext(), tls_idx);
#ifdef SHOW_SYMBOLS
    print_address(f, instr_addr, "RETURN @ ");
    print_address(f, target_addr, "\t to ");
#else
    dr_fprintf(f, "RETURN @ "PFX" to "PFX"\n", instr_addr, target_addr);
#endif
}

static dr_emit_flags_t
event_app_instruction(void *drcontext, void *tag, instrlist_t *bb, instr_t *instr,
    bool for_trace, bool translating, void *user_data)
{
#ifdef VERBOSE
    if (drmgr_is_first_instr(drcontext, instr)) {
        dr_printf("in dr_basic_block(tag="PFX")\n", tag);
# if VERBOSE_VERBOSE
        instrlist_disassemble(drcontext, tag, bb, STDOUT);
# endif
    }
#endif
    /* instrument calls and returns -- ignore far calls/rets */
    if (instr_is_call_direct(instr)) {
        dr_insert_call_instrumentation(drcontext, bb, instr, (app_pc)at_call);
    }
    else if (instr_is_call_indirect(instr)) {
        dr_insert_mbr_instrumentation(drcontext, bb, instr, (app_pc)at_call_ind,
            SPILL_SLOT_1);
    }
    else if (instr_is_return(instr)) {
        dr_insert_mbr_instrumentation(drcontext, bb, instr, (app_pc)at_return,
            SPILL_SLOT_1);
    }
    return DR_EMIT_DEFAULT;
}

I checked "static void at_call" function, return value of dr_get_mcontext is 0 (false), mc.xsp is always 0.

[wooddii]

Sry, it is my error I compiled it with

#define WINDOWS 1
#define X86_32 1

need #define X86_64 1