Alien-TinyCC

 view release on metacpan or  search on metacpan

src/tccrun.c  view on Meta::CPAN

{
    int (*prog_main)(int, char **);
    int ret;

    if (tcc_relocate(s1, TCC_RELOCATE_AUTO) < 0)
        return -1;

    prog_main = tcc_get_symbol_err(s1, s1->runtime_main);

#ifdef CONFIG_TCC_BACKTRACE
    if (s1->do_debug) {
        set_exception_handler();
        rt_prog_main = prog_main;
    }
#endif

#ifdef CONFIG_TCC_BCHECK
    if (s1->do_bounds_check) {
        void (*bound_init)(void);
        void (*bound_exit)(void);
        /* set error function */
        rt_bound_error_msg = tcc_get_symbol_err(s1, "__bound_error_msg");
        /* XXX: use .init section so that it also work in binary ? */
        bound_init = tcc_get_symbol_err(s1, "__bound_init");
        bound_exit = tcc_get_symbol_err(s1, "__bound_exit");
        bound_init();
        ret = (*prog_main)(argc, argv);
        bound_exit();
    } else
#endif
        ret = (*prog_main)(argc, argv);
    return ret;
}

/* relocate code. Return -1 on error, required size if ptr is NULL,
   otherwise copy code into buffer passed by the caller */
static int tcc_relocate_ex(TCCState *s1, void *ptr)
{
    Section *s;
    unsigned long offset, length;
    addr_t mem;
    int i;

    if (NULL == ptr) {
        s1->nb_errors = 0;
#ifdef TCC_TARGET_PE
        pe_output_file(s1, NULL);
#else
        tcc_add_runtime(s1);
        relocate_common_syms();
        tcc_add_linker_symbols(s1);
        build_got_entries(s1);
#endif
        if (s1->nb_errors)
            return -1;
    }

    offset = 0, mem = (addr_t)ptr;
    for(i = 1; i < s1->nb_sections; i++) {
        s = s1->sections[i];
        if (0 == (s->sh_flags & SHF_ALLOC))
            continue;
        length = s->data_offset;
        s->sh_addr = mem ? (mem + offset + 15) & ~15 : 0;
        offset = (offset + length + 15) & ~15;
    }
    offset += 16;

    /* relocate symbols */
    relocate_syms(s1, 1);
    if (s1->nb_errors)
        return -1;

#ifdef TCC_HAS_RUNTIME_PLTGOT
    s1->runtime_plt_and_got_offset = 0;
    s1->runtime_plt_and_got = (char *)(mem + offset);
    /* double the size of the buffer for got and plt entries
       XXX: calculate exact size for them? */
    offset *= 2;
#endif

    if (0 == mem)
        return offset;

    /* relocate each section */
    for(i = 1; i < s1->nb_sections; i++) {
        s = s1->sections[i];
        if (s->reloc)
            relocate_section(s1, s);
    }

    for(i = 1; i < s1->nb_sections; i++) {
        s = s1->sections[i];
        if (0 == (s->sh_flags & SHF_ALLOC))
            continue;
        length = s->data_offset;
        // printf("%-12s %08x %04x\n", s->name, s->sh_addr, length);
        ptr = (void*)s->sh_addr;
        if (NULL == s->data || s->sh_type == SHT_NOBITS)
            memset(ptr, 0, length);
        else
            memcpy(ptr, s->data, length);
        /* mark executable sections as executable in memory */
        if (s->sh_flags & SHF_EXECINSTR)
            set_pages_executable(ptr, length);
    }

#ifdef TCC_HAS_RUNTIME_PLTGOT
    set_pages_executable(s1->runtime_plt_and_got,
                         s1->runtime_plt_and_got_offset);
#endif

#ifdef _WIN64
    win64_add_function_table(s1);
#endif
    return 0;
}

/* ------------------------------------------------------------- */
/* allow to run code in memory */

static void set_pages_executable(void *ptr, unsigned long length)
{
#ifdef _WIN32
    unsigned long old_protect;
    VirtualProtect(ptr, length, PAGE_EXECUTE_READWRITE, &old_protect);
#else
#ifndef PAGESIZE
# define PAGESIZE 4096
#endif
    addr_t start, end;
    start = (addr_t)ptr & ~(PAGESIZE - 1);
    end = (addr_t)ptr + length;
    end = (end + PAGESIZE - 1) & ~(PAGESIZE - 1);
    mprotect((void *)start, end - start, PROT_READ | PROT_WRITE | PROT_EXEC);
    __clear_cache(ptr, ptr + length);
#endif
}

/* ------------------------------------------------------------- */
#ifdef CONFIG_TCC_BACKTRACE

ST_FUNC void tcc_set_num_callers(int n)
{
    rt_num_callers = n;
}

/* print the position in the source file of PC value 'pc' by reading
   the stabs debug information */
static addr_t rt_printline(addr_t wanted_pc, const char *msg)
{
    char func_name[128], last_func_name[128];
    addr_t func_addr, last_pc, pc;
    const char *incl_files[INCLUDE_STACK_SIZE];
    int incl_index, len, last_line_num, i;
    const char *str, *p;

    Stab_Sym *stab_sym = NULL, *stab_sym_end, *sym;
    int stab_len = 0;
    char *stab_str = NULL;

    if (stab_section) {
        stab_len = stab_section->data_offset;
        stab_sym = (Stab_Sym *)stab_section->data;

src/tccrun.c  view on Meta::CPAN

    for(i=0;i<rt_num_callers;i++) {
        if (rt_get_caller_pc(&pc, uc, i) < 0)
            break;
        pc = rt_printline(pc, i ? "by" : "at");
        if (pc == (addr_t)rt_prog_main && pc)
            break;
    }
}

/* ------------------------------------------------------------- */
#ifndef _WIN32

/* signal handler for fatal errors */
static void sig_error(int signum, siginfo_t *siginf, void *puc)
{
    ucontext_t *uc = puc;

    switch(signum) {
    case SIGFPE:
        switch(siginf->si_code) {
        case FPE_INTDIV:
        case FPE_FLTDIV:
            rt_error(uc, "division by zero");
            break;
        default:
            rt_error(uc, "floating point exception");
            break;
        }
        break;
    case SIGBUS:
    case SIGSEGV:
        if (rt_bound_error_msg && *rt_bound_error_msg)
            rt_error(uc, *rt_bound_error_msg);
        else
            rt_error(uc, "dereferencing invalid pointer");
        break;
    case SIGILL:
        rt_error(uc, "illegal instruction");
        break;
    case SIGABRT:
        rt_error(uc, "abort() called");
        break;
    default:
        rt_error(uc, "caught signal %d", signum);
        break;
    }
    exit(255);
}

#ifndef SA_SIGINFO
# define SA_SIGINFO 0x00000004u
#endif

/* Generate a stack backtrace when a CPU exception occurs. */
static void set_exception_handler(void)
{
    struct sigaction sigact;
    /* install TCC signal handlers to print debug info on fatal
       runtime errors */
    sigact.sa_flags = SA_SIGINFO | SA_RESETHAND;
    sigact.sa_sigaction = sig_error;
    sigemptyset(&sigact.sa_mask);
    sigaction(SIGFPE, &sigact, NULL);
    sigaction(SIGILL, &sigact, NULL);
    sigaction(SIGSEGV, &sigact, NULL);
    sigaction(SIGBUS, &sigact, NULL);
    sigaction(SIGABRT, &sigact, NULL);
}

/* ------------------------------------------------------------- */
#ifdef __i386__

/* fix for glibc 2.1 */
#ifndef REG_EIP
#define REG_EIP EIP
#define REG_EBP EBP
#endif

/* return the PC at frame level 'level'. Return negative if not found */
static int rt_get_caller_pc(addr_t *paddr, ucontext_t *uc, int level)
{
    addr_t fp;
    int i;

    if (level == 0) {
#if defined(__APPLE__)
        *paddr = uc->uc_mcontext->__ss.__eip;
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
        *paddr = uc->uc_mcontext.mc_eip;
#elif defined(__dietlibc__)
        *paddr = uc->uc_mcontext.eip;
#else
        *paddr = uc->uc_mcontext.gregs[REG_EIP];
#endif
        return 0;
    } else {
#if defined(__APPLE__)
        fp = uc->uc_mcontext->__ss.__ebp;
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
        fp = uc->uc_mcontext.mc_ebp;
#elif defined(__dietlibc__)
        fp = uc->uc_mcontext.ebp;
#else
        fp = uc->uc_mcontext.gregs[REG_EBP];
#endif
        for(i=1;i<level;i++) {
            /* XXX: check address validity with program info */
            if (fp <= 0x1000 || fp >= 0xc0000000)
                return -1;
            fp = ((addr_t *)fp)[0];
        }
        *paddr = ((addr_t *)fp)[1];
        return 0;
    }
}

/* ------------------------------------------------------------- */
#elif defined(__x86_64__)

/* return the PC at frame level 'level'. Return negative if not found */

src/tccrun.c  view on Meta::CPAN

        rt_error(uc, "stack overflow");
        break;
    case EXCEPTION_INT_DIVIDE_BY_ZERO:
        rt_error(uc, "division by zero");
        break;
    default:
        rt_error(uc, "exception caught");
        break;
    }
    return EXCEPTION_EXECUTE_HANDLER;
}

/* Generate a stack backtrace when a CPU exception occurs. */
static void set_exception_handler(void)
{
    SetUnhandledExceptionFilter(cpu_exception_handler);
}

#ifdef _WIN64
static void win64_add_function_table(TCCState *s1)
{
    RtlAddFunctionTable(
        (RUNTIME_FUNCTION*)s1->uw_pdata->sh_addr,
        s1->uw_pdata->data_offset / sizeof (RUNTIME_FUNCTION),
        text_section->sh_addr
        );
}
#endif

/* return the PC at frame level 'level'. Return non zero if not found */
static int rt_get_caller_pc(addr_t *paddr, CONTEXT *uc, int level)
{
    addr_t fp, pc;
    int i;
#ifdef _WIN64
    pc = uc->Rip;
    fp = uc->Rbp;
#else
    pc = uc->Eip;
    fp = uc->Ebp;
#endif
    if (level > 0) {
        for(i=1;i<level;i++) {
	    /* XXX: check address validity with program info */
	    if (fp <= 0x1000 || fp >= 0xc0000000)
		return -1;
	    fp = ((addr_t*)fp)[0];
	}
        pc = ((addr_t*)fp)[1];
    }
    *paddr = pc;
    return 0;
}

#endif /* _WIN32 */
#endif /* CONFIG_TCC_BACKTRACE */
/* ------------------------------------------------------------- */
#ifdef CONFIG_TCC_STATIC

/* dummy function for profiling */
ST_FUNC void *dlopen(const char *filename, int flag)
{
    return NULL;
}

ST_FUNC void dlclose(void *p)
{
}

ST_FUNC const char *dlerror(void)
{
    return "error";
}

typedef struct TCCSyms {
    char *str;
    void *ptr;
} TCCSyms;


/* add the symbol you want here if no dynamic linking is done */
static TCCSyms tcc_syms[] = {
#if !defined(CONFIG_TCCBOOT)
#define TCCSYM(a) { #a, &a, },
    TCCSYM(printf)
    TCCSYM(fprintf)
    TCCSYM(fopen)
    TCCSYM(fclose)
#undef TCCSYM
#endif
    { NULL, NULL },
};

ST_FUNC void *resolve_sym(TCCState *s1, const char *symbol)
{
    TCCSyms *p;
    p = tcc_syms;
    while (p->str != NULL) {
        if (!strcmp(p->str, symbol))
            return p->ptr;
        p++;
    }
    return NULL;
}

#elif !defined(_WIN32)

ST_FUNC void *resolve_sym(TCCState *s1, const char *sym)
{
    return dlsym(RTLD_DEFAULT, sym);
}

#endif /* CONFIG_TCC_STATIC */
#endif /* TCC_IS_NATIVE */
/* ------------------------------------------------------------- */