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Bug #10044 Bug in shm_remove() and inadequate implementation of SYSVSem.
Submitted: 2001-03-28 20:18 UTC Modified: 2001-05-15 03:49 UTC
From: swm at linuxworld dot com dot au Assigned:
Status: Closed Package: Semaphore related
PHP Version: 4.0.4pl1 OS: Linux
Private report: No CVE-ID: None
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From: swm at linuxworld dot com dot au
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 [2001-03-28 20:18 UTC] swm at linuxworld dot com dot au
There is a bug in shm_remove() that comes from the fact
that the function is treating its argument, shm_identifier,
as a shm key. The function argument should be
shm_identifier. The patch appended fixes this problem.

There is also an implementation issue with SYSV Semaphores.
There is no method of removing unrequired semaphores. See
the patch appended for a function, sem_remove, which can do
this.

I am happy to take over maintenance of this section.

As for the patches, I have had to cut and paste them so I am
unsure if Mozilla has wrapped certain lines. If so, I will
email them.

-----
Patch
-----

--- ext/sysvshm/sysvshm.c.orig  Fri Mar 16 01:22:16 2001
+++ ext/sysvshm/sysvshm.c       Fri Mar 16 01:42:15 2001
@@ -173,26 +173,40 @@
 /* }}} */
 /* {{{ proto int shm_remove(int shm_identifier)
    Removes shared memory from Unix systems */
+
+/* patched to use the correct argument Fri Mar 16 01:22:50
EST 2001
+ * Gavin Sherry gavin@linuxworld.com.au
+ */
+
 PHP_FUNCTION(shm_remove)
 {
-       pval **arg_key;
+       pval **arg_id;
        long id;
-       key_t key;
+       int type;
+       sysvshm_shm *shm_list_ptr;
 
-       if(ZEND_NUM_ARGS() != 1 || zend_get_parameters_ex(1,
&arg_key) == FAILUR
E) {
+       if(ZEND_NUM_ARGS() != 1 || zend_get_parameters_ex(1,
&arg_id) == FAILURE
) {
                WRONG_PARAM_COUNT;
        }
 
-       convert_to_long_ex(arg_key);
+       convert_to_long_ex(arg_id);
        
-       key = (*arg_key)->value.lval;
+       id = (*arg_id)->value.lval;
 
+/*
+ * this isn't what we're looking to do 
+ */
+
+/*
        if((id=shmget(key,0,0))<0) {
                php_error(E_WARNING, "%d is not a existing
SysV shared memory ke
y", key);
                RETURN_FALSE;
        }
-       if(shmctl(id,IPC_RMID,NULL)<0) {
-               php_error(E_WARNING, "shm_remove() failed
for key 0x%x: %s", key
, strerror(errno));
+*/
+
+       shm_list_ptr = (sysvshm_shm *) zend_list_find(id,
&type);
+       if(shmctl(shm_list_ptr->id,IPC_RMID,NULL)<0) {
+               php_error(E_WARNING, "shm_remove() failed
for key 0x%x, id %i: %s",shm_list_ptr->key,id,strerror(errno));
                RETURN_FALSE;
        } 

--- ext/sysvsem/php_sysvsem.h.orig      Fri Mar 16 01:44:26 2001
+++ ext/sysvsem/php_sysvsem.h   Fri Mar 16 01:44:17 2001
@@ -30,6 +30,7 @@
 PHP_FUNCTION(sem_get);
 PHP_FUNCTION(sem_acquire);
 PHP_FUNCTION(sem_release);
+PHP_FUNCTION(sem_remove);
 
 typedef struct {
        int le_sem;

--- ext/sysvsem/sysvsem.c.orig  Thu Mar 15 22:40:18 2001
+++ ext/sysvsem/sysvsem.c       Thu Mar 15 23:15:17 2001
@@ -53,6 +53,7 @@
        PHP_FE(sem_get,                 NULL)
        PHP_FE(sem_acquire,             NULL)
        PHP_FE(sem_release,             NULL)
+       PHP_FE(sem_remove,              NULL)
        {NULL, NULL, NULL}
 };
 
@@ -92,6 +93,14 @@
        sysvsem_sem *sem_ptr = (sysvsem_sem *)rsrc->ptr;
        struct sembuf sop[2];
 
+/*
+ * if count == -1, semaphore has been removed
+ * Need better way to handle this
+ */
+
+       if(sem_ptr->count == -1) {
+               return;
+       }
        /* Decrement the usage count. */
 
        sop[0].sem_num = SYSVSEM_USAGE;
@@ -343,6 +352,63 @@
 {
        php_sysvsem_semop(INTERNAL_FUNCTION_PARAM_PASSTHRU, 0);
 }
+/* }}} */
+
+
+
+
+/* {{{ proto int sem_remove(int 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)
+{
+        pval **arg_id;
+        int id,type;
+       sysvsem_sem *sem_ptr;
+#if HAVE_SEMUN
+       union semun un;
+#endif
+        if(ZEND_NUM_ARGS() != 1 ||
zend_get_parameters_ex(1, &arg_id) == FAILUR
E) {
+                WRONG_PARAM_COUNT;
+        }
+        convert_to_long_ex(arg_id);
+
+        id = (*arg_id)->value.lval;
+
+        sem_ptr = (sysvsem_sem *) zend_list_find(id, &type);
+
+        if (type!=php_sysvsem_module.le_sem) {
+                php_error(E_WARNING, "%d is not a SysV
semaphore index", id);
+                RETURN_FALSE;
+        }
+
+#if HAVE_SEMUN
+        if(semctl(sem_ptr->semid,NULL,IPC_STAT,un)<0) {
+#else
+       if(semctl(sem_ptr->semid,NULL,IPC_STAT,NULL)<0) {
+#endif
+                php_error(E_WARNING, "%d is not a existing
SysV Semaphore Id", 
id);
+                RETURN_FALSE;
+        }
+
+       if(semctl(sem_ptr->semid,NULL,IPC_RMID,NULL)<0) {
+                php_error(E_WARNING, "sem_remove() failed
for id %d: %s", id, s
trerror(errno));
+                RETURN_FALSE;
+        }
+       
+       /* let release_sysvsem_sem knows we have removed
+        * the semaphore to avoid issues with releasing.
+        */ 
+
+       sem_ptr->count = -1;
+        RETURN_TRUE;
+}
+
 /* }}} */
 
 #endif /* HAVE_SYSVSEM */

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 [2001-05-15 03:49 UTC] swm@php.net
Fix in current CVS
 
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