summaryrefslogtreecommitdiff
path: root/ext/fiddle/handle.c
blob: 4cfeedaedde0c1b2ee7337cbc5dc52aa19e404d4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
#include <ruby.h>
#include <fiddle.h>

VALUE rb_cHandle;

struct dl_handle {
    void *ptr;
    int  open;
    int  enable_close;
};

#ifdef _WIN32
# ifndef _WIN32_WCE
static void *
w32_coredll(void)
{
    MEMORY_BASIC_INFORMATION m;
    memset(&m, 0, sizeof(m));
    if( !VirtualQuery(_errno, &m, sizeof(m)) ) return NULL;
    return m.AllocationBase;
}
# endif

static int
w32_dlclose(void *ptr)
{
# ifndef _WIN32_WCE
    if( ptr == w32_coredll() ) return 0;
# endif
    if( FreeLibrary((HMODULE)ptr) ) return 0;
    return errno = rb_w32_map_errno(GetLastError());
}
#define dlclose(ptr) w32_dlclose(ptr)
#endif

static void
fiddle_handle_free(void *ptr)
{
    struct dl_handle *fiddle_handle = ptr;
    if( fiddle_handle->ptr && fiddle_handle->open && fiddle_handle->enable_close ){
	dlclose(fiddle_handle->ptr);
    }
    xfree(ptr);
}

static size_t
fiddle_handle_memsize(const void *ptr)
{
    return ptr ? sizeof(struct dl_handle) : 0;
}

static const rb_data_type_t fiddle_handle_data_type = {
    "fiddle/handle",
    {0, fiddle_handle_free, fiddle_handle_memsize,},
};

/*
 * call-seq: close
 *
 * Close this handle.
 *
 * Calling close more than once will raise a Fiddle::DLError exception.
 */
static VALUE
rb_fiddle_handle_close(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    if(fiddle_handle->open) {
	int ret = dlclose(fiddle_handle->ptr);
	fiddle_handle->open = 0;

	/* Check dlclose for successful return value */
	if(ret) {
#if defined(HAVE_DLERROR)
	    rb_raise(rb_eFiddleError, "%s", dlerror());
#else
	    rb_raise(rb_eFiddleError, "could not close handle");
#endif
	}
	return INT2NUM(ret);
    }
    rb_raise(rb_eFiddleError, "dlclose() called too many times");

    UNREACHABLE;
}

static VALUE
rb_fiddle_handle_s_allocate(VALUE klass)
{
    VALUE obj;
    struct dl_handle *fiddle_handle;

    obj = TypedData_Make_Struct(rb_cHandle, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    fiddle_handle->ptr  = 0;
    fiddle_handle->open = 0;
    fiddle_handle->enable_close = 0;

    return obj;
}

static VALUE
predefined_fiddle_handle(void *handle)
{
    VALUE obj = rb_fiddle_handle_s_allocate(rb_cHandle);
    struct dl_handle *fiddle_handle = DATA_PTR(obj);

    fiddle_handle->ptr = handle;
    fiddle_handle->open = 1;
    OBJ_FREEZE(obj);
    return obj;
}

/*
 * call-seq:
 *    new(library = nil, flags = Fiddle::RTLD_LAZY | Fiddle::RTLD_GLOBAL)
 *
 * Create a new handler that opens +library+ with +flags+.
 *
 * If no +library+ is specified or +nil+ is given, DEFAULT is used, which is
 * the equivalent to RTLD_DEFAULT. See <code>man 3 dlopen</code> for more.
 *
 *	lib = Fiddle::Handle.new
 *
 * The default is dependent on OS, and provide a handle for all libraries
 * already loaded. For example, in most cases you can use this to access +libc+
 * functions, or ruby functions like +rb_str_new+.
 */
static VALUE
rb_fiddle_handle_initialize(int argc, VALUE argv[], VALUE self)
{
    void *ptr;
    struct dl_handle *fiddle_handle;
    VALUE lib, flag;
    char  *clib;
    int   cflag;
    const char *err;

    switch( rb_scan_args(argc, argv, "02", &lib, &flag) ){
      case 0:
	clib = NULL;
	cflag = RTLD_LAZY | RTLD_GLOBAL;
	break;
      case 1:
	clib = NIL_P(lib) ? NULL : StringValuePtr(lib);
	cflag = RTLD_LAZY | RTLD_GLOBAL;
	break;
      case 2:
	clib = NIL_P(lib) ? NULL : StringValuePtr(lib);
	cflag = NUM2INT(flag);
	break;
      default:
	rb_bug("rb_fiddle_handle_new");
    }

    rb_secure(2);

#if defined(_WIN32)
    if( !clib ){
	HANDLE rb_libruby_handle(void);
	ptr = rb_libruby_handle();
    }
    else if( STRCASECMP(clib, "libc") == 0
# ifdef RUBY_COREDLL
	     || STRCASECMP(clib, RUBY_COREDLL) == 0
	     || STRCASECMP(clib, RUBY_COREDLL".dll") == 0
# endif
	){
# ifdef _WIN32_WCE
	ptr = dlopen("coredll.dll", cflag);
# else
	(void)cflag;
	ptr = w32_coredll();
# endif
    }
    else
#endif
	ptr = dlopen(clib, cflag);
#if defined(HAVE_DLERROR)
    if( !ptr && (err = dlerror()) ){
	rb_raise(rb_eFiddleError, "%s", err);
    }
#else
    if( !ptr ){
	err = dlerror();
	rb_raise(rb_eFiddleError, "%s", err);
    }
#endif
    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    if( fiddle_handle->ptr && fiddle_handle->open && fiddle_handle->enable_close ){
	dlclose(fiddle_handle->ptr);
    }
    fiddle_handle->ptr = ptr;
    fiddle_handle->open = 1;
    fiddle_handle->enable_close = 0;

    if( rb_block_given_p() ){
	rb_ensure(rb_yield, self, rb_fiddle_handle_close, self);
    }

    return Qnil;
}

/*
 * call-seq: enable_close
 *
 * Enable a call to dlclose() when this handle is garbage collected.
 */
static VALUE
rb_fiddle_handle_enable_close(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    fiddle_handle->enable_close = 1;
    return Qnil;
}

/*
 * call-seq: disable_close
 *
 * Disable a call to dlclose() when this handle is garbage collected.
 */
static VALUE
rb_fiddle_handle_disable_close(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    fiddle_handle->enable_close = 0;
    return Qnil;
}

/*
 * call-seq: close_enabled?
 *
 * Returns +true+ if dlclose() will be called when this handle is garbage collected.
 *
 * See man(3) dlclose() for more info.
 */
static VALUE
rb_fiddle_handle_close_enabled_p(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);

    if(fiddle_handle->enable_close) return Qtrue;
    return Qfalse;
}

/*
 * call-seq: to_i
 *
 * Returns the memory address for this handle.
 */
static VALUE
rb_fiddle_handle_to_i(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    return PTR2NUM(fiddle_handle);
}

static VALUE fiddle_handle_sym(void *handle, const char *symbol);

/*
 * Document-method: sym
 *
 * call-seq: sym(name)
 *
 * Get the address as an Integer for the function named +name+.
 */
static VALUE
rb_fiddle_handle_sym(VALUE self, VALUE sym)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    if( ! fiddle_handle->open ){
	rb_raise(rb_eFiddleError, "closed handle");
    }

    return fiddle_handle_sym(fiddle_handle->ptr, StringValueCStr(sym));
}

#ifndef RTLD_NEXT
#define RTLD_NEXT NULL
#endif
#ifndef RTLD_DEFAULT
#define RTLD_DEFAULT NULL
#endif

/*
 * Document-method: sym
 *
 * call-seq: sym(name)
 *
 * Get the address as an Integer for the function named +name+.  The function
 * is searched via dlsym on RTLD_NEXT.
 *
 * See man(3) dlsym() for more info.
 */
static VALUE
rb_fiddle_handle_s_sym(VALUE self, VALUE sym)
{
    return fiddle_handle_sym(RTLD_NEXT, StringValueCStr(sym));
}

static VALUE
fiddle_handle_sym(void *handle, const char *name)
{
#if defined(HAVE_DLERROR)
    const char *err;
# define CHECK_DLERROR if ((err = dlerror()) != 0) { func = 0; }
#else
# define CHECK_DLERROR
#endif
    void (*func)();

    rb_secure(2);
#ifdef HAVE_DLERROR
    dlerror();
#endif
    func = (void (*)())(VALUE)dlsym(handle, name);
    CHECK_DLERROR;
#if defined(FUNC_STDCALL)
    if( !func ){
	int  i;
	int  len = (int)strlen(name);
	char *name_n;
#if defined(__CYGWIN__) || defined(_WIN32) || defined(__MINGW32__)
	{
	    char *name_a = (char*)xmalloc(len+2);
	    strcpy(name_a, name);
	    name_n = name_a;
	    name_a[len]   = 'A';
	    name_a[len+1] = '\0';
	    func = dlsym(handle, name_a);
	    CHECK_DLERROR;
	    if( func ) goto found;
	    name_n = xrealloc(name_a, len+6);
	}
#else
	name_n = (char*)xmalloc(len+6);
#endif
	memcpy(name_n, name, len);
	name_n[len++] = '@';
	for( i = 0; i < 256; i += 4 ){
	    sprintf(name_n + len, "%d", i);
	    func = dlsym(handle, name_n);
	    CHECK_DLERROR;
	    if( func ) break;
	}
	if( func ) goto found;
	name_n[len-1] = 'A';
	name_n[len++] = '@';
	for( i = 0; i < 256; i += 4 ){
	    sprintf(name_n + len, "%d", i);
	    func = dlsym(handle, name_n);
	    CHECK_DLERROR;
	    if( func ) break;
	}
      found:
	xfree(name_n);
    }
#endif
    if( !func ){
	rb_raise(rb_eFiddleError, "unknown symbol \"%s\"", name);
    }

    return PTR2NUM(func);
}

void
Init_fiddle_handle(void)
{
    /*
     * Document-class: Fiddle::Handle
     *
     * The Fiddle::Handle is the manner to access the dynamic library
     *
     * == Example
     *
     * === Setup
     *
     *   libc_so = "/lib64/libc.so.6"
     *   => "/lib64/libc.so.6"
     *   @handle = Fiddle::Handle.new(libc_so)
     *   => #<Fiddle::Handle:0x00000000d69ef8>
     *
     * === Setup, with flags
     *
     *   libc_so = "/lib64/libc.so.6"
     *   => "/lib64/libc.so.6"
     *   @handle = Fiddle::Handle.new(libc_so, Fiddle::RTLD_LAZY | Fiddle::RTLD_GLOBAL)
     *   => #<Fiddle::Handle:0x00000000d69ef8>
     *
     * See RTLD_LAZY and RTLD_GLOBAL
     *
     * === Addresses to symbols
     *
     *   strcpy_addr = @handle['strcpy']
     *   => 140062278451968
     *
     * or
     *
     *   strcpy_addr = @handle.sym('strcpy')
     *   => 140062278451968
     *
     */
    rb_cHandle = rb_define_class_under(mFiddle, "Handle", rb_cObject);
    rb_define_alloc_func(rb_cHandle, rb_fiddle_handle_s_allocate);
    rb_define_singleton_method(rb_cHandle, "sym", rb_fiddle_handle_s_sym, 1);
    rb_define_singleton_method(rb_cHandle, "[]", rb_fiddle_handle_s_sym,  1);

    /* Document-const: NEXT
     *
     * A predefined pseudo-handle of RTLD_NEXT
     *
     * Which will find the next occurrence of a function in the search order
     * after the current library.
     */
    rb_define_const(rb_cHandle, "NEXT", predefined_fiddle_handle(RTLD_NEXT));

    /* Document-const: DEFAULT
     *
     * A predefined pseudo-handle of RTLD_DEFAULT
     *
     * Which will find the first occurrence of the desired symbol using the
     * default library search order
     */
    rb_define_const(rb_cHandle, "DEFAULT", predefined_fiddle_handle(RTLD_DEFAULT));

    /* Document-const: RTLD_GLOBAL
     *
     * rtld Fiddle::Handle flag.
     *
     * The symbols defined by this library will be made available for symbol
     * resolution of subsequently loaded libraries.
     */
    rb_define_const(rb_cHandle, "RTLD_GLOBAL", INT2NUM(RTLD_GLOBAL));

    /* Document-const: RTLD_LAZY
     *
     * rtld Fiddle::Handle flag.
     *
     * Perform lazy binding.  Only resolve symbols as the code that references
     * them is executed.  If the  symbol is never referenced, then it is never
     * resolved.  (Lazy binding is only performed for function references;
     * references to variables are always immediately bound when the library
     * is loaded.)
     */
    rb_define_const(rb_cHandle, "RTLD_LAZY",   INT2NUM(RTLD_LAZY));

    /* Document-const: RTLD_NOW
     *
     * rtld Fiddle::Handle flag.
     *
     * If this value is specified or the environment variable LD_BIND_NOW is
     * set to a nonempty string, all undefined symbols in the library are
     * resolved before Fiddle.dlopen returns.  If this cannot be done an error
     * is returned.
     */
    rb_define_const(rb_cHandle, "RTLD_NOW",    INT2NUM(RTLD_NOW));

    rb_define_method(rb_cHandle, "initialize", rb_fiddle_handle_initialize, -1);
    rb_define_method(rb_cHandle, "to_i", rb_fiddle_handle_to_i, 0);
    rb_define_method(rb_cHandle, "close", rb_fiddle_handle_close, 0);
    rb_define_method(rb_cHandle, "sym",  rb_fiddle_handle_sym, 1);
    rb_define_method(rb_cHandle, "[]",  rb_fiddle_handle_sym,  1);
    rb_define_method(rb_cHandle, "disable_close", rb_fiddle_handle_disable_close, 0);
    rb_define_method(rb_cHandle, "enable_close", rb_fiddle_handle_enable_close, 0);
    rb_define_method(rb_cHandle, "close_enabled?", rb_fiddle_handle_close_enabled_p, 0);
}

/* vim: set noet sws=4 sw=4: */