diff options
Diffstat (limited to 'ext/sysvsem/sysvsem.c')
| -rw-r--r-- | ext/sysvsem/sysvsem.c | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/ext/sysvsem/sysvsem.c b/ext/sysvsem/sysvsem.c new file mode 100644 index 0000000..b6e5ccb --- /dev/null +++ b/ext/sysvsem/sysvsem.c @@ -0,0 +1,408 @@ +/* + +----------------------------------------------------------------------+ + | PHP Version 5 | + +----------------------------------------------------------------------+ + | Copyright (c) 1997-2013 The PHP Group | + +----------------------------------------------------------------------+ + | This source file is subject to version 3.01 of the PHP license, | + | that is bundled with this package in the file LICENSE, and is | + | available through the world-wide-web at the following url: | + | http://www.php.net/license/3_01.txt | + | If you did not receive a copy of the PHP license and are unable to | + | obtain it through the world-wide-web, please send a note to | + | license@php.net so we can mail you a copy immediately. | + +----------------------------------------------------------------------+ + | Authors: Tom May <tom@go2net.com> | + | Gavin Sherry <gavin@linuxworld.com.au> | + +----------------------------------------------------------------------+ + */ + +/* $Id$ */ + +/* Latest update build anc tested on Linux 2.2.14 + * + * This has been built and tested on Solaris 2.6 and Linux 2.1.122. + * It may not compile or execute correctly on other systems. + * + * sas: Works for me on Linux 2.0.36 and FreeBSD 3.0-current + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include "php.h" + +#if HAVE_SYSVSEM + +#include <sys/types.h> +#include <sys/ipc.h> +#include <sys/sem.h> +#include <errno.h> + +#include "php_sysvsem.h" + +#if !HAVE_SEMUN + +union semun { + int val; /* value for SETVAL */ + struct semid_ds *buf; /* buffer for IPC_STAT, IPC_SET */ + unsigned short int *array; /* array for GETALL, SETALL */ + struct seminfo *__buf; /* buffer for IPC_INFO */ +}; + +#undef HAVE_SEMUN +#define HAVE_SEMUN 1 + +#endif + +/* {{{ arginfo */ +ZEND_BEGIN_ARG_INFO_EX(arginfo_sem_get, 0, 0, 1) + ZEND_ARG_INFO(0, key) + ZEND_ARG_INFO(0, max_acquire) + ZEND_ARG_INFO(0, perm) + ZEND_ARG_INFO(0, auto_release) +ZEND_END_ARG_INFO() + +ZEND_BEGIN_ARG_INFO_EX(arginfo_sem_acquire, 0, 0, 1) + ZEND_ARG_INFO(0, sem_identifier) +ZEND_END_ARG_INFO() + +ZEND_BEGIN_ARG_INFO_EX(arginfo_sem_release, 0, 0, 1) + ZEND_ARG_INFO(0, sem_identifier) +ZEND_END_ARG_INFO() + +ZEND_BEGIN_ARG_INFO_EX(arginfo_sem_remove, 0, 0, 1) + ZEND_ARG_INFO(0, sem_identifier) +ZEND_END_ARG_INFO() +/* }}} */ + +/* {{{ sysvsem_functions[] + */ +const zend_function_entry sysvsem_functions[] = { + PHP_FE(sem_get, arginfo_sem_get) + PHP_FE(sem_acquire, arginfo_sem_acquire) + PHP_FE(sem_release, arginfo_sem_release) + PHP_FE(sem_remove, arginfo_sem_remove) + PHP_FE_END +}; +/* }}} */ + +/* {{{ sysvsem_module_entry + */ +zend_module_entry sysvsem_module_entry = { + STANDARD_MODULE_HEADER, + "sysvsem", + sysvsem_functions, + PHP_MINIT(sysvsem), + NULL, + NULL, + NULL, + NULL, + NO_VERSION_YET, + STANDARD_MODULE_PROPERTIES +}; +/* }}} */ + +#ifdef COMPILE_DL_SYSVSEM +ZEND_GET_MODULE(sysvsem) +#endif + + +THREAD_LS sysvsem_module php_sysvsem_module; + +/* Semaphore functions using System V semaphores. Each semaphore + * actually consists of three semaphores allocated as a unit under the + * same key. Semaphore 0 (SYSVSEM_SEM) is the actual semaphore, it is + * initialized to max_acquire and decremented as processes acquire it. + * The value of semaphore 1 (SYSVSEM_USAGE) is a count of the number + * of processes using the semaphore. After calling semget(), if a + * process finds that the usage count is 1, it will set the value of + * SYSVSEM_SEM to max_acquire. This allows max_acquire to be set and + * track the PHP code without having a global init routine or external + * semaphore init code. Except see the bug regarding a race condition + * php_sysvsem_get(). Semaphore 2 (SYSVSEM_SETVAL) serializes the + * calls to GETVAL SYSVSEM_USAGE and SETVAL SYSVSEM_SEM. It can be + * acquired only when it is zero. + */ + +#define SYSVSEM_SEM 0 +#define SYSVSEM_USAGE 1 +#define SYSVSEM_SETVAL 2 + +/* {{{ release_sysvsem_sem + */ +static void release_sysvsem_sem(zend_rsrc_list_entry *rsrc TSRMLS_DC) +{ + sysvsem_sem *sem_ptr = (sysvsem_sem *)rsrc->ptr; + struct sembuf sop[2]; + int opcount = 1; +/* + * if count == -1, semaphore has been removed + * Need better way to handle this + */ + + if (sem_ptr->count == -1 || !sem_ptr->auto_release) { + efree(sem_ptr); + return; + } + /* Decrement the usage count. */ + + sop[0].sem_num = SYSVSEM_USAGE; + sop[0].sem_op = -1; + sop[0].sem_flg = SEM_UNDO; + + /* Release the semaphore if it has been acquired but not released. */ + + if (sem_ptr->count) { + + sop[1].sem_num = SYSVSEM_SEM; + sop[1].sem_op = sem_ptr->count; + sop[1].sem_flg = SEM_UNDO; + + opcount++; + } + + semop(sem_ptr->semid, sop, opcount); + efree(sem_ptr); +} +/* }}} */ + +/* {{{ PHP_MINIT_FUNCTION + */ +PHP_MINIT_FUNCTION(sysvsem) +{ + php_sysvsem_module.le_sem = zend_register_list_destructors_ex(release_sysvsem_sem, NULL, "sysvsem", module_number); + return SUCCESS; +} +/* }}} */ + +#define SETVAL_WANTS_PTR + +#if defined(_AIX) +#undef SETVAL_WANTS_PTR +#endif + +/* {{{ proto resource sem_get(int key [, int max_acquire [, int perm [, int auto_release]]) + Return an id for the semaphore with the given key, and allow max_acquire (default 1) processes to acquire it simultaneously */ +PHP_FUNCTION(sem_get) +{ + long key, max_acquire = 1, perm = 0666, auto_release = 1; + int semid; + struct sembuf sop[3]; + int count; + sysvsem_sem *sem_ptr; + + if (FAILURE == zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l|lll", &key, &max_acquire, &perm, &auto_release)) { + RETURN_FALSE; + } + + /* Get/create the semaphore. Note that we rely on the semaphores + * being zeroed when they are created. Despite the fact that + * the(?) Linux semget() man page says they are not initialized, + * the kernel versions 2.0.x and 2.1.z do in fact zero them. + */ + + semid = semget(key, 3, perm|IPC_CREAT); + if (semid == -1) { + php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed for key 0x%lx: %s", key, strerror(errno)); + RETURN_FALSE; + } + + /* Find out how many processes are using this semaphore. Note + * that on Linux (at least) there is a race condition here because + * semaphore undo on process exit is not atomic, so we could + * acquire SYSVSEM_SETVAL before a crashed process has decremented + * SYSVSEM_USAGE in which case count will be greater than it + * should be and we won't set max_acquire. Fortunately this + * doesn't actually matter in practice. + */ + + /* Wait for sem 1 to be zero . . . */ + + sop[0].sem_num = SYSVSEM_SETVAL; + sop[0].sem_op = 0; + sop[0].sem_flg = 0; + + /* . . . and increment it so it becomes non-zero . . . */ + + sop[1].sem_num = SYSVSEM_SETVAL; + sop[1].sem_op = 1; + sop[1].sem_flg = SEM_UNDO; + + /* . . . and increment the usage count. */ + + sop[2].sem_num = SYSVSEM_USAGE; + sop[2].sem_op = 1; + sop[2].sem_flg = SEM_UNDO; + while (semop(semid, sop, 3) == -1) { + if (errno != EINTR) { + php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed acquiring SYSVSEM_SETVAL for key 0x%lx: %s", key, strerror(errno)); + break; + } + } + + /* Get the usage count. */ + count = semctl(semid, SYSVSEM_USAGE, GETVAL, NULL); + if (count == -1) { + php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed for key 0x%lx: %s", key, strerror(errno)); + } + + /* If we are the only user, then take this opportunity to set the max. */ + + if (count == 1) { +#if HAVE_SEMUN + /* This is correct for Linux which has union semun. */ + union semun semarg; + semarg.val = max_acquire; + if (semctl(semid, SYSVSEM_SEM, SETVAL, semarg) == -1) { + php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed for key 0x%lx: %s", key, strerror(errno)); + } +#elif defined(SETVAL_WANTS_PTR) + /* This is correct for Solaris 2.6 which does not have union semun. */ + if (semctl(semid, SYSVSEM_SEM, SETVAL, &max_acquire) == -1) { + php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed for key 0x%lx: %s", key, strerror(errno)); + } +#else + /* This works for i.e. AIX */ + if (semctl(semid, SYSVSEM_SEM, SETVAL, max_acquire) == -1) { + php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed for key 0x%lx: %s", key, strerror(errno)); + } +#endif + } + + /* Set semaphore 1 back to zero. */ + + sop[0].sem_num = SYSVSEM_SETVAL; + sop[0].sem_op = -1; + sop[0].sem_flg = SEM_UNDO; + while (semop(semid, sop, 1) == -1) { + if (errno != EINTR) { + php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed releasing SYSVSEM_SETVAL for key 0x%lx: %s", key, strerror(errno)); + break; + } + } + + sem_ptr = (sysvsem_sem *) emalloc(sizeof(sysvsem_sem)); + sem_ptr->key = key; + sem_ptr->semid = semid; + sem_ptr->count = 0; + sem_ptr->auto_release = auto_release; + + sem_ptr->id = ZEND_REGISTER_RESOURCE(return_value, sem_ptr, php_sysvsem_module.le_sem); +} +/* }}} */ + +/* {{{ php_sysvsem_semop + */ +static void php_sysvsem_semop(INTERNAL_FUNCTION_PARAMETERS, int acquire) +{ + zval *arg_id; + sysvsem_sem *sem_ptr; + struct sembuf sop; + + if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "r", &arg_id) == FAILURE) { + return; + } + + ZEND_FETCH_RESOURCE(sem_ptr, sysvsem_sem *, &arg_id, -1, "SysV semaphore", php_sysvsem_module.le_sem); + + if (!acquire && sem_ptr->count == 0) { + php_error_docref(NULL TSRMLS_CC, E_WARNING, "SysV semaphore %ld (key 0x%x) is not currently acquired", Z_LVAL_P(arg_id), sem_ptr->key); + RETURN_FALSE; + } + + sop.sem_num = SYSVSEM_SEM; + sop.sem_op = acquire ? -1 : 1; + sop.sem_flg = SEM_UNDO; + + while (semop(sem_ptr->semid, &sop, 1) == -1) { + if (errno != EINTR) { + php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed to %s key 0x%x: %s", acquire ? "acquire" : "release", sem_ptr->key, strerror(errno)); + RETURN_FALSE; + } + } + + sem_ptr->count -= acquire ? -1 : 1; + RETURN_TRUE; +} +/* }}} */ + +/* {{{ proto bool sem_acquire(resource id) + Acquires the semaphore with the given id, blocking if necessary */ +PHP_FUNCTION(sem_acquire) +{ + php_sysvsem_semop(INTERNAL_FUNCTION_PARAM_PASSTHRU, 1); +} +/* }}} */ + +/* {{{ proto bool sem_release(resource id) + Releases the semaphore with the given id */ +PHP_FUNCTION(sem_release) +{ + php_sysvsem_semop(INTERNAL_FUNCTION_PARAM_PASSTHRU, 0); +} +/* }}} */ + +/* {{{ proto bool sem_remove(resource id) + Removes semaphore from Unix systems */ + +/* + * contributed by Gavin Sherry gavin@linuxworld.com.au + * Fri Mar 16 00:50:13 EST 2001 + */ + +PHP_FUNCTION(sem_remove) +{ + zval *arg_id; + sysvsem_sem *sem_ptr; +#if HAVE_SEMUN + union semun un; + struct semid_ds buf; +#endif + + if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "r", &arg_id) == FAILURE) { + return; + } + + ZEND_FETCH_RESOURCE(sem_ptr, sysvsem_sem *, &arg_id, -1, "SysV semaphore", php_sysvsem_module.le_sem); + +#if HAVE_SEMUN + un.buf = &buf; + if (semctl(sem_ptr->semid, 0, IPC_STAT, un) < 0) { +#else + if (semctl(sem_ptr->semid, 0, IPC_STAT, NULL) < 0) { +#endif + php_error_docref(NULL TSRMLS_CC, E_WARNING, "SysV semaphore %ld does not (any longer) exist", Z_LVAL_P(arg_id)); + RETURN_FALSE; + } + +#if HAVE_SEMUN + if (semctl(sem_ptr->semid, 0, IPC_RMID, un) < 0) { +#else + if (semctl(sem_ptr->semid, 0, IPC_RMID, NULL) < 0) { +#endif + php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed for SysV sempphore %ld: %s", Z_LVAL_P(arg_id), strerror(errno)); + RETURN_FALSE; + } + + /* let release_sysvsem_sem know we have removed + * the semaphore to avoid issues with releasing. + */ + + sem_ptr->count = -1; + RETURN_TRUE; +} + +/* }}} */ + +#endif /* HAVE_SYSVSEM */ + +/* + * Local variables: + * tab-width: 4 + * c-basic-offset: 4 + * End: + * vim600: sw=4 ts=4 fdm=marker + * vim<600: sw=4 ts=4 + */ |