xref: /PHP-7.4/ext/sysvshm/sysvshm.c (revision 92ac598a)
1 /*
2    +----------------------------------------------------------------------+
3    | PHP Version 7                                                        |
4    +----------------------------------------------------------------------+
5    | Copyright (c) The PHP Group                                          |
6    +----------------------------------------------------------------------+
7    | This source file is subject to version 3.01 of the PHP license,      |
8    | that is bundled with this package in the file LICENSE, and is        |
9    | available through the world-wide-web at the following url:           |
10    | http://www.php.net/license/3_01.txt                                  |
11    | If you did not receive a copy of the PHP license and are unable to   |
12    | obtain it through the world-wide-web, please send a note to          |
13    | license@php.net so we can mail you a copy immediately.               |
14    +----------------------------------------------------------------------+
15    | Author: Christian Cartus <cartus@atrior.de>                          |
16    +----------------------------------------------------------------------+
17  */
18 
19 /* This has been built and tested on Linux 2.2.14
20  *
21  * This has been built and tested on Solaris 2.6.
22  * It may not compile or execute correctly on other systems.
23  */
24 
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28 
29 #include "php.h"
30 
31 #if HAVE_SYSVSHM
32 
33 #include <errno.h>
34 
35 #include "php_sysvshm.h"
36 #include "ext/standard/info.h"
37 #include "ext/standard/php_var.h"
38 #include "zend_smart_str.h"
39 #include "php_ini.h"
40 
41 /* {{{ arginfo */
42 ZEND_BEGIN_ARG_INFO_EX(arginfo_shm_attach, 0, 0, 1)
43 	ZEND_ARG_INFO(0, key)
44 	ZEND_ARG_INFO(0, memsize)
45 	ZEND_ARG_INFO(0, perm)
46 ZEND_END_ARG_INFO()
47 
48 ZEND_BEGIN_ARG_INFO_EX(arginfo_shm_detach, 0, 0, 1)
49 	ZEND_ARG_INFO(0, shm_identifier)
50 ZEND_END_ARG_INFO()
51 
52 ZEND_BEGIN_ARG_INFO_EX(arginfo_shm_has_var, 0, 0, 2)
53 	ZEND_ARG_INFO(0, id)
54 	ZEND_ARG_INFO(0, variable_key)
55 ZEND_END_ARG_INFO()
56 
57 ZEND_BEGIN_ARG_INFO_EX(arginfo_shm_remove, 0, 0, 1)
58 	ZEND_ARG_INFO(0, shm_identifier)
59 ZEND_END_ARG_INFO()
60 
61 ZEND_BEGIN_ARG_INFO_EX(arginfo_shm_put_var, 0, 0, 3)
62 	ZEND_ARG_INFO(0, shm_identifier)
63 	ZEND_ARG_INFO(0, variable_key)
64 	ZEND_ARG_INFO(0, variable)
65 ZEND_END_ARG_INFO()
66 
67 ZEND_BEGIN_ARG_INFO_EX(arginfo_shm_get_var, 0, 0, 2)
68 	ZEND_ARG_INFO(0, id)
69 	ZEND_ARG_INFO(0, variable_key)
70 ZEND_END_ARG_INFO()
71 
72 ZEND_BEGIN_ARG_INFO_EX(arginfo_shm_remove_var, 0, 0, 2)
73 	ZEND_ARG_INFO(0, id)
74 	ZEND_ARG_INFO(0, variable_key)
75 ZEND_END_ARG_INFO()
76 /* }}} */
77 
78 /* {{{ sysvshm_functions[]
79  */
80 static const zend_function_entry sysvshm_functions[] = {
81 	PHP_FE(shm_attach,		arginfo_shm_attach)
82 	PHP_FE(shm_remove,		arginfo_shm_detach)
83 	PHP_FE(shm_detach, 		arginfo_shm_remove)
84 	PHP_FE(shm_put_var,		arginfo_shm_put_var)
85 	PHP_FE(shm_has_var,		arginfo_shm_has_var)
86 	PHP_FE(shm_get_var,		arginfo_shm_get_var)
87 	PHP_FE(shm_remove_var,	arginfo_shm_remove_var)
88 	PHP_FE_END
89 };
90 /* }}} */
91 
92 /* {{{ sysvshm_module_entry
93  */
94 zend_module_entry sysvshm_module_entry = {
95 	STANDARD_MODULE_HEADER,
96 	"sysvshm",
97 	sysvshm_functions,
98 	PHP_MINIT(sysvshm),
99 	NULL,
100 	NULL,
101 	NULL,
102 	PHP_MINFO(sysvshm),
103 	PHP_SYSVSHM_VERSION,
104 	STANDARD_MODULE_PROPERTIES
105 };
106 /* }}} */
107 
108 #ifdef COMPILE_DL_SYSVSHM
109 ZEND_GET_MODULE(sysvshm)
110 #endif
111 
112 #undef shm_ptr					/* undefine AIX-specific macro */
113 
114 #define SHM_FETCH_RESOURCE(shm_ptr, z_ptr) do { \
115 	if ((shm_ptr = (sysvshm_shm *)zend_fetch_resource(Z_RES_P(z_ptr), PHP_SHM_RSRC_NAME, php_sysvshm.le_shm)) == NULL) { \
116 		RETURN_FALSE; \
117 	} \
118 } while (0)
119 
120 THREAD_LS sysvshm_module php_sysvshm;
121 
122 static int php_put_shm_data(sysvshm_chunk_head *ptr, zend_long key, const char *data, zend_long len);
123 static zend_long php_check_shm_data(sysvshm_chunk_head *ptr, zend_long key);
124 static int php_remove_shm_data(sysvshm_chunk_head *ptr, zend_long shm_varpos);
125 
126 /* {{{ php_release_sysvshm
127  */
php_release_sysvshm(zend_resource * rsrc)128 static void php_release_sysvshm(zend_resource *rsrc)
129 {
130 	sysvshm_shm *shm_ptr = (sysvshm_shm *) rsrc->ptr;
131 	shmdt((void *) shm_ptr->ptr);
132 	efree(shm_ptr);
133 }
134 /* }}} */
135 
136 /* {{{ PHP_MINIT_FUNCTION
137  */
PHP_MINIT_FUNCTION(sysvshm)138 PHP_MINIT_FUNCTION(sysvshm)
139 {
140 	php_sysvshm.le_shm = zend_register_list_destructors_ex(php_release_sysvshm, NULL, PHP_SHM_RSRC_NAME, module_number);
141 
142 	if (cfg_get_long("sysvshm.init_mem", &php_sysvshm.init_mem) == FAILURE) {
143 		php_sysvshm.init_mem=10000;
144 	}
145 	return SUCCESS;
146 }
147 /* }}} */
148 
149 /* {{{ PHP_MINFO_FUNCTION
150  */
PHP_MINFO_FUNCTION(sysvshm)151 PHP_MINFO_FUNCTION(sysvshm)
152 {
153 	php_info_print_table_start();
154 	php_info_print_table_row(2, "sysvshm support", "enabled");
155 	php_info_print_table_end();
156 }
157 /* }}} */
158 
159 /* {{{ proto int shm_attach(int key [, int memsize [, int perm]])
160    Creates or open a shared memory segment */
PHP_FUNCTION(shm_attach)161 PHP_FUNCTION(shm_attach)
162 {
163 	sysvshm_shm *shm_list_ptr;
164 	char *shm_ptr;
165 	sysvshm_chunk_head *chunk_ptr;
166 	zend_long shm_key, shm_id, shm_size = php_sysvshm.init_mem, shm_flag = 0666;
167 
168 	if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS(), "l|ll", &shm_key, &shm_size, &shm_flag)) {
169 		return;
170 	}
171 
172 	if (shm_size < 1) {
173 		php_error_docref(NULL, E_WARNING, "Segment size must be greater than zero");
174 		RETURN_FALSE;
175   	}
176 
177 	shm_list_ptr = (sysvshm_shm *) emalloc(sizeof(sysvshm_shm));
178 
179 	/* get the id from a specified key or create new shared memory */
180 	if ((shm_id = shmget(shm_key, 0, 0)) < 0) {
181 		if (shm_size < (zend_long)sizeof(sysvshm_chunk_head)) {
182 			php_error_docref(NULL, E_WARNING, "failed for key 0x" ZEND_XLONG_FMT ": memorysize too small", shm_key);
183 			efree(shm_list_ptr);
184 			RETURN_FALSE;
185 		}
186 		if ((shm_id = shmget(shm_key, shm_size, shm_flag | IPC_CREAT | IPC_EXCL)) < 0) {
187 			php_error_docref(NULL, E_WARNING, "failed for key 0x" ZEND_XLONG_FMT ": %s", shm_key, strerror(errno));
188 			efree(shm_list_ptr);
189 			RETURN_FALSE;
190 		}
191 	}
192 
193 	if ((shm_ptr = shmat(shm_id, NULL, 0)) == (void *) -1) {
194 		php_error_docref(NULL, E_WARNING, "failed for key 0x" ZEND_XLONG_FMT ": %s", shm_key, strerror(errno));
195 		efree(shm_list_ptr);
196 		RETURN_FALSE;
197 	}
198 
199 	/* check if shm is already initialized */
200 	chunk_ptr = (sysvshm_chunk_head *) shm_ptr;
201 	if (strcmp((char*) &(chunk_ptr->magic), "PHP_SM") != 0) {
202 		strcpy((char*) &(chunk_ptr->magic), "PHP_SM");
203 		chunk_ptr->start = sizeof(sysvshm_chunk_head);
204 		chunk_ptr->end = chunk_ptr->start;
205 		chunk_ptr->total = shm_size;
206 		chunk_ptr->free = shm_size-chunk_ptr->end;
207 	}
208 
209 	shm_list_ptr->key = shm_key;
210 	shm_list_ptr->id = shm_id;
211 	shm_list_ptr->ptr = chunk_ptr;
212 
213 	RETURN_RES(zend_register_resource(shm_list_ptr, php_sysvshm.le_shm));
214 }
215 /* }}} */
216 
217 /* {{{ proto bool shm_detach(resource shm_identifier)
218    Disconnects from shared memory segment */
PHP_FUNCTION(shm_detach)219 PHP_FUNCTION(shm_detach)
220 {
221 	zval *shm_id;
222 	sysvshm_shm *shm_list_ptr;
223 
224 	if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS(), "r", &shm_id)) {
225 		return;
226 	}
227 	SHM_FETCH_RESOURCE(shm_list_ptr, shm_id);
228 	RETURN_BOOL(SUCCESS == zend_list_close(Z_RES_P(shm_id)));
229 }
230 /* }}} */
231 
232 /* {{{ proto bool shm_remove(resource shm_identifier)
233    Removes shared memory from Unix systems */
PHP_FUNCTION(shm_remove)234 PHP_FUNCTION(shm_remove)
235 {
236 	zval *shm_id;
237 	sysvshm_shm *shm_list_ptr;
238 
239 	if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS(), "r", &shm_id)) {
240 		return;
241 	}
242 	SHM_FETCH_RESOURCE(shm_list_ptr, shm_id);
243 
244 	if (shmctl(shm_list_ptr->id, IPC_RMID, NULL) < 0) {
245 		php_error_docref(NULL, E_WARNING, "failed for key 0x%x, id " ZEND_LONG_FMT ": %s", shm_list_ptr->key, Z_LVAL_P(shm_id), strerror(errno));
246 		RETURN_FALSE;
247 	}
248 
249 	RETURN_TRUE;
250 }
251 /* }}} */
252 
253 /* {{{ proto bool shm_put_var(resource shm_identifier, int variable_key, mixed variable)
254    Inserts or updates a variable in shared memory */
PHP_FUNCTION(shm_put_var)255 PHP_FUNCTION(shm_put_var)
256 {
257 	zval *shm_id, *arg_var;
258 	int ret;
259 	zend_long shm_key;
260 	sysvshm_shm *shm_list_ptr;
261 	smart_str shm_var = {0};
262 	php_serialize_data_t var_hash;
263 
264 	if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS(), "rlz", &shm_id, &shm_key, &arg_var)) {
265 		return;
266 	}
267 
268 	/* setup string-variable and serialize */
269 	PHP_VAR_SERIALIZE_INIT(var_hash);
270 	php_var_serialize(&shm_var, arg_var, &var_hash);
271 	PHP_VAR_SERIALIZE_DESTROY(var_hash);
272 
273 	shm_list_ptr = zend_fetch_resource(Z_RES_P(shm_id), PHP_SHM_RSRC_NAME, php_sysvshm.le_shm);
274 	if (!shm_list_ptr) {
275 		smart_str_free(&shm_var);
276 		RETURN_FALSE;
277 	}
278 
279 	/* insert serialized variable into shared memory */
280 	ret = php_put_shm_data(shm_list_ptr->ptr, shm_key, shm_var.s? ZSTR_VAL(shm_var.s) : NULL, shm_var.s? ZSTR_LEN(shm_var.s) : 0);
281 
282 	/* free string */
283 	smart_str_free(&shm_var);
284 
285 	if (ret == -1) {
286 		php_error_docref(NULL, E_WARNING, "not enough shared memory left");
287 		RETURN_FALSE;
288 	}
289 	RETURN_TRUE;
290 }
291 /* }}} */
292 
293 /* {{{ proto mixed shm_get_var(resource id, int variable_key)
294    Returns a variable from shared memory */
PHP_FUNCTION(shm_get_var)295 PHP_FUNCTION(shm_get_var)
296 {
297 	zval *shm_id;
298 	zend_long shm_key;
299 	sysvshm_shm *shm_list_ptr;
300 	char *shm_data;
301 	zend_long shm_varpos;
302 	sysvshm_chunk *shm_var;
303 	php_unserialize_data_t var_hash;
304 
305 	if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS(), "rl", &shm_id, &shm_key)) {
306 		return;
307 	}
308 	SHM_FETCH_RESOURCE(shm_list_ptr, shm_id);
309 
310 	/* setup string-variable and serialize */
311 	/* get serialized variable from shared memory */
312 	shm_varpos = php_check_shm_data((shm_list_ptr->ptr), shm_key);
313 
314 	if (shm_varpos < 0) {
315 		php_error_docref(NULL, E_WARNING, "variable key " ZEND_LONG_FMT " doesn't exist", shm_key);
316 		RETURN_FALSE;
317 	}
318 	shm_var = (sysvshm_chunk*) ((char *)shm_list_ptr->ptr + shm_varpos);
319 	shm_data = &shm_var->mem;
320 
321 	PHP_VAR_UNSERIALIZE_INIT(var_hash);
322 	if (php_var_unserialize(return_value, (const unsigned char **) &shm_data, (unsigned char *) shm_data + shm_var->length, &var_hash) != 1) {
323 		php_error_docref(NULL, E_WARNING, "variable data in shared memory is corrupted");
324 		RETVAL_FALSE;
325 	}
326 	PHP_VAR_UNSERIALIZE_DESTROY(var_hash);
327 }
328 /* }}} */
329 
330 /* {{{ proto bool shm_has_var(resource id, int variable_key)
331 	Checks whether a specific entry exists */
PHP_FUNCTION(shm_has_var)332 PHP_FUNCTION(shm_has_var)
333 {
334 	zval *shm_id;
335 	zend_long shm_key;
336 	sysvshm_shm *shm_list_ptr;
337 
338 	if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS(), "rl", &shm_id, &shm_key)) {
339 		return;
340 	}
341 	SHM_FETCH_RESOURCE(shm_list_ptr, shm_id);
342 	RETURN_BOOL(php_check_shm_data(shm_list_ptr->ptr, shm_key) >= 0);
343 }
344 /* }}} */
345 
346 /* {{{ proto bool shm_remove_var(resource id, int variable_key)
347    Removes variable from shared memory */
PHP_FUNCTION(shm_remove_var)348 PHP_FUNCTION(shm_remove_var)
349 {
350 	zval *shm_id;
351 	zend_long shm_key, shm_varpos;
352 	sysvshm_shm *shm_list_ptr;
353 
354 	if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS(), "rl", &shm_id, &shm_key)) {
355 		return;
356 	}
357 	SHM_FETCH_RESOURCE(shm_list_ptr, shm_id);
358 
359 	shm_varpos = php_check_shm_data((shm_list_ptr->ptr), shm_key);
360 
361 	if (shm_varpos < 0) {
362 		php_error_docref(NULL, E_WARNING, "variable key " ZEND_LONG_FMT " doesn't exist", shm_key);
363 		RETURN_FALSE;
364 	}
365 	php_remove_shm_data((shm_list_ptr->ptr), shm_varpos);
366 	RETURN_TRUE;
367 }
368 /* }}} */
369 
370 /* {{{ php_put_shm_data
371  * inserts an ascii-string into shared memory */
php_put_shm_data(sysvshm_chunk_head * ptr,zend_long key,const char * data,zend_long len)372 static int php_put_shm_data(sysvshm_chunk_head *ptr, zend_long key, const char *data, zend_long len)
373 {
374 	sysvshm_chunk *shm_var;
375 	zend_long total_size;
376 	zend_long shm_varpos;
377 
378 	total_size = ((zend_long) (len + sizeof(sysvshm_chunk) - 1) / sizeof(zend_long)) * sizeof(zend_long) + sizeof(zend_long); /* zend_long alligment */
379 
380 	if ((shm_varpos = php_check_shm_data(ptr, key)) > 0) {
381 		php_remove_shm_data(ptr, shm_varpos);
382 	}
383 
384 	if (ptr->free < total_size) {
385 		return -1; /* not enough memory */
386 	}
387 
388 	shm_var = (sysvshm_chunk *) ((char *) ptr + ptr->end);
389 	shm_var->key = key;
390 	shm_var->length = len;
391 	shm_var->next = total_size;
392 	memcpy(&(shm_var->mem), data, len);
393 	ptr->end += total_size;
394 	ptr->free -= total_size;
395 	return 0;
396 }
397 /* }}} */
398 
399 /* {{{ php_check_shm_data
400  */
php_check_shm_data(sysvshm_chunk_head * ptr,zend_long key)401 static zend_long php_check_shm_data(sysvshm_chunk_head *ptr, zend_long key)
402 {
403 	zend_long pos;
404 	sysvshm_chunk *shm_var;
405 
406 	pos = ptr->start;
407 
408 	for (;;) {
409 		if (pos >= ptr->end) {
410 			return -1;
411 		}
412 		shm_var = (sysvshm_chunk*) ((char *) ptr + pos);
413 		if (shm_var->key == key) {
414 			return pos;
415 		}
416 		pos += shm_var->next;
417 
418 		if (shm_var->next <= 0 || pos < ptr->start) {
419 			return -1;
420 		}
421 	}
422 	return -1;
423 }
424 /* }}} */
425 
426 /* {{{ php_remove_shm_data
427  */
php_remove_shm_data(sysvshm_chunk_head * ptr,zend_long shm_varpos)428 static int php_remove_shm_data(sysvshm_chunk_head *ptr, zend_long shm_varpos)
429 {
430 	sysvshm_chunk *chunk_ptr, *next_chunk_ptr;
431 	zend_long memcpy_len;
432 
433 	chunk_ptr = (sysvshm_chunk *) ((char *) ptr + shm_varpos);
434 	next_chunk_ptr = (sysvshm_chunk *) ((char *) ptr + shm_varpos + chunk_ptr->next);
435 
436 	memcpy_len = ptr->end-shm_varpos - chunk_ptr->next;
437 	ptr->free += chunk_ptr->next;
438 	ptr->end -= chunk_ptr->next;
439 	if (memcpy_len > 0) {
440 		memmove(chunk_ptr, next_chunk_ptr, memcpy_len);
441 	}
442 	return 0;
443 }
444 /* }}} */
445 
446 #endif /* HAVE_SYSVSHM */
447