New PHP5 APC - version 3.0.18, using PHP5 5.2.0-8+etch10,

[php5-apc.git] / apc_sem.c

diff --git a/apc_sem.c b/apc_sem.c
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+/*
+  +----------------------------------------------------------------------+
+  | APC                                                                  |
+  +----------------------------------------------------------------------+
+  | Copyright (c) 2006 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: Daniel Cowgill <dcowgill@communityconnect.com>              |
+  +----------------------------------------------------------------------+
+
+   This software was contributed to PHP by Community Connect Inc. in 2002
+   and revised in 2005 by Yahoo! Inc. to add support for PHP 5.1.
+   Future revisions and derivatives of this source code must acknowledge
+   Community Connect Inc. as the original contributor of this module by
+   leaving this note intact in the source code.
+
+   All other licensing and usage conditions are those of the PHP Group.
+
+ */
+
+/* $Id: apc_sem.c,v 3.16 2006/03/12 00:31:45 rasmus Exp $ */
+
+#include "apc_sem.h"
+#include "apc.h"
+#include "php.h"
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/sem.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#if HAVE_SEMUN
+/* we have semun, no need to define */
+#else
+#undef HAVE_SEMUN
+union semun {
+    int val;                  /* value for SETVAL */
+    struct semid_ds *buf;     /* buffer for IPC_STAT, IPC_SET */
+    unsigned short *array;    /* array for GETALL, SETALL */
+                              /* Linux specific part: */
+    struct seminfo *__buf;    /* buffer for IPC_INFO */
+};
+#define HAVE_SEMUN 1
+#endif
+
+#ifndef SEM_R
+# define SEM_R 0444
+#endif
+#ifndef SEM_A
+# define SEM_A 0222
+#endif
+
+/* always use SEM_UNDO, otherwise we risk deadlock */
+#define USE_SEM_UNDO
+
+#ifdef USE_SEM_UNDO
+# define UNDO SEM_UNDO
+#else
+# define UNDO 0
+#endif
+
+int apc_sem_create(const char* pathname, int proj, int initval)
+{
+    int semid;
+    int perms;
+    union semun arg;
+    key_t key;
+
+    perms = 0777;
+
+    key = IPC_PRIVATE;
+    if (pathname != NULL) {
+        if ((key = ftok(pathname, proj)) < 0) {
+            apc_eprint("apc_sem_create: ftok(%s,%d) failed:", pathname, proj);
+        }
+    }
+    
+    if ((semid = semget(key, 1, IPC_CREAT | IPC_EXCL | perms)) >= 0) {
+        /* sempahore created for the first time, initialize now */
+        arg.val = initval;
+        if (semctl(semid, 0, SETVAL, arg) < 0) {
+            apc_eprint("apc_sem_create: semctl(%d,...) failed:", semid);
+        }
+    }
+    else if (errno == EEXIST) {
+        /* sempahore already exists, don't initialize */
+        if ((semid = semget(key, 1, perms)) < 0) {
+            apc_eprint("apc_sem_create: semget(%u,...) failed:", key);
+        }
+        /* insert <sleazy way to avoid race condition> here */
+    }
+    else {
+        apc_eprint("apc_sem_create: semget(%u,...) failed:", key);
+    }
+
+    return semid;
+}
+
+void apc_sem_destroy(int semid)
+{
+    /* we expect this call to fail often, so we do not check */
+    union semun arg;
+    semctl(semid, 0, IPC_RMID, arg);
+}
+
+void apc_sem_lock(int semid)
+{
+    struct sembuf op;
+
+    op.sem_num = 0;
+    op.sem_op  = -1;
+    op.sem_flg = UNDO;
+
+    if (semop(semid, &op, 1) < 0) {
+        if (errno != EINTR) {
+            apc_eprint("apc_sem_lock: semop(%d) failed:", semid);
+        }
+    }
+}
+
+void apc_sem_unlock(int semid)
+{
+    struct sembuf op;
+
+    op.sem_num = 0;
+    op.sem_op  = 1;
+    op.sem_flg = UNDO;
+
+    if (semop(semid, &op, 1) < 0) {
+        if (errno != EINTR) {
+            apc_eprint("apc_sem_unlock: semop(%d) failed:", semid);
+        }
+    }
+}
+
+void apc_sem_wait_for_zero(int semid)
+{
+    struct sembuf op;
+
+    op.sem_num = 0;
+    op.sem_op  = 0;
+    op.sem_flg = UNDO;
+
+    if (semop(semid, &op, 1) < 0) {
+        if (errno != EINTR) {
+            apc_eprint("apc_sem_waitforzero: semop(%d) failed:", semid);
+        }
+    }
+}
+
+int apc_sem_get_value(int semid)
+{
+    union semun arg;
+    unsigned short val[1];
+
+    arg.array = val;
+    if (semctl(semid, 0, GETALL, arg) < 0) {
+        apc_eprint("apc_sem_getvalue: semctl(%d,...) failed:", semid);
+    }
+    return val[0];
+}
+
+/*
+ * Local variables:
+ * tab-width: 4
+ * c-basic-offset: 4
+ * End:
+ * vim600: expandtab sw=4 ts=4 sts=4 fdm=marker
+ * vim<600: expandtab sw=4 ts=4 sts=4
+ */