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Commit1a67e48

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Add shared memory and semaphore routines for Win32.
Also update copyright to be ours, with approval from Jan.
1 parentd670bf3 commit1a67e48

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2 files changed

+359
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lines changed

2 files changed

+359
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lines changed

‎src/backend/port/win32/sem.c

Lines changed: 239 additions & 0 deletions
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/*-------------------------------------------------------------------------
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*
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* sem.c
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* Microsoft Windows Win32 Semaphores Emulation
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*
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* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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*
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*-------------------------------------------------------------------------
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*/
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#include"postgres.h"
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#include"storage/shmem.h"
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#include<errno.h>
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typedefstruct {
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intm_numSems;
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off_tm_semaphoreHandles;// offset from beginning of header
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off_tm_semaphoreCounts;// offset from beginning of header
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}win32_sem_set_hdr;
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/* Control of a semaphore pool. The pool is an area in which we stored all
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** the semIds of the pool. The first long is the number of semaphore
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** allocated in the pool followed by semaphore handles
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*/
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int
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semctl(intsemId,intsemNum,intflag,unionsemunsemun)
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{
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win32_sem_set_hdr*the_set= (win32_sem_set_hdr*)MAKE_PTR(semId);
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/* semNum might be 0 */
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/* semun.array contains the sem initial values */
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int*sem_counts= (int*)((off_t)the_set+the_set->m_semaphoreCounts);
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/* Fix the count of all sem of the pool to semun.array */
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if (flag==SETALL)
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{
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inti;
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structsembufsops;
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sops.sem_flg=IPC_NOWAIT;
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for (i=0;i<the_set->m_numSems;++i) {
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if (semun.array[i]==sem_counts[i])
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continue;/* Nothing to do */
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if (semun.array[i]<sem_counts[i])
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sops.sem_op=-1;
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else
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sops.sem_op=1;
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sops.sem_num=i;
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/* Quickly lock/unlock the semaphore (if we can) */
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if (semop(semId,&sops,1)<0)
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return-1;
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}
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return1;
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}
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/* Fix the count of one semaphore to semun.val */
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elseif (flag==SETVAL)
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{
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if (semun.val!=sem_counts[semNum]) {
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structsembufsops;
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sops.sem_flg=IPC_NOWAIT;
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sops.sem_num=semNum;
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if (semun.val<sem_counts[semNum])
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sops.sem_op=-1;
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else
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sops.sem_op=1;
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/* Quickly lock/unlock the semaphore (if we can) */
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if (semop(semId,&sops,1)<0)
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return-1;
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}
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return1;
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}
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/* Delete the pool */
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elseif (flag==IPC_RMID)
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{
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inti;
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HANDLE*sem_handles= (HANDLE*)((off_t)the_set+the_set->m_semaphoreHandles);
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/* Loop over all semaphore to delete them */
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for (i=0;i<the_set->m_numSems;++i)
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CloseHandle(sem_handles[i]);
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return1;
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}
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/* Get the current semaphore count */
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elseif (flag==GETNCNT)
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{
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returnthe_set->m_numSems;
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}
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/* Get the current semaphore count of the first semaphore in the pool */
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elseif (flag==GETVAL)
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{
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returnsem_counts[semNum];
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}
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/* Other commands not yet supported */
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else
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{
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errno=EINVAL;
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return-1;
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}
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}
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/* Find a pool id based on IPC key */
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int
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semget(intsemKey,intsemNum,intflags)
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{
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charsemname[32];
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charcur_num[20];
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DWORDlast_error;
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char*num_part;
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boolans= true;
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SECURITY_ATTRIBUTESsec_attrs;
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HANDLEcur_handle;
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boolfound= false;
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Sizesem_set_size=sizeof(win32_sem_set_hdr)+semNum* (sizeof(HANDLE)+sizeof(int));
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HANDLE*sem_handles=NULL;
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int*sem_counts=NULL;
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sec_attrs.nLength=sizeof(sec_attrs);
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sec_attrs.lpSecurityDescriptor=NULL;
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sec_attrs.bInheritHandle= TRUE;
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sprintf(semname,"PG_SEMSET.%d.",semKey);
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num_part=semname+strlen(semname);
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strcpy(num_part,_itoa(_getpid()*-1,cur_num,10));/* For shared memory, include the pid */
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win32_sem_set_hdr*new_set= (win32_sem_set_hdr*)ShmemInitStruct(semname,sem_set_size,&found);
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if (found) {
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/* This should *never* happen */
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errno=EEXIST;
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return-1;
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}
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new_set->m_numSems=semNum;
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new_set->m_semaphoreHandles=sizeof(win32_sem_set_hdr);// array starts after header
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new_set->m_semaphoreCounts=new_set->m_semaphoreHandles+ (sizeof(HANDLE)*semNum);
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sem_handles= (HANDLE*)((off_t)new_set+new_set->m_semaphoreHandles);
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sem_counts= (int*)((off_t)new_set+new_set->m_semaphoreCounts);
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for (inti=0;i<semNum&&ans;++i) {
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strcpy(num_part,_itoa(i,cur_num,10));
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if (flags&IPC_CREAT)
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cur_handle=CreateSemaphore(&sec_attrs,0,1,semname);
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else
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cur_handle=OpenSemaphore(SEMAPHORE_ALL_ACCESS, TRUE,semname);
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sem_handles[i]=cur_handle;
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last_error=GetLastError();
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if (!cur_handle)
166+
{
167+
errno=EACCES;
168+
ans= false;
169+
}
170+
elseif (last_error==ERROR_ALREADY_EXISTS&& (flags& (IPC_CREAT |IPC_EXCL)))
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{
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errno=EEXIST;
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ans= false;
174+
}
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}
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if (ans) {
178+
returnMAKE_OFFSET(new_set);
179+
}else {
180+
// Blow away what we've got right now...
181+
for (inti=0;i<semNum;++i) {
182+
if (sem_handles[i])
183+
CloseHandle(sem_handles[i]);
184+
else
185+
break;
186+
}
187+
188+
return-1;
189+
}
190+
}
191+
192+
/* Acquire or release in the semaphore pool */
193+
int
194+
semop(intsemId,structsembuf*sops,intnsops)
195+
{
196+
win32_sem_set_hdr*the_set= (win32_sem_set_hdr*)MAKE_PTR(semId);
197+
HANDLE*sem_handles= (HANDLE*)((off_t)the_set+the_set->m_semaphoreHandles);
198+
int*sem_counts= (int*)((off_t)the_set+the_set->m_semaphoreCounts);
199+
HANDLEcur_handle;
200+
201+
if (nsops!=1) {
202+
/* Not supported (we return on 1st success, and don't cancel earlier ops) */
203+
errno=E2BIG;
204+
return-1;
205+
}
206+
207+
cur_handle=sem_handles[sops[0].sem_num];
208+
209+
if (sops[0].sem_op==-1)
210+
{
211+
DWORDret;
212+
if (sops[0].sem_flg&IPC_NOWAIT)
213+
ret=WaitForSingleObject(cur_handle,0);
214+
else
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ret=WaitForSingleObject(cur_handle,INFINITE);
216+
217+
if (ret==WAIT_OBJECT_0) {
218+
/* We got it! */
219+
sem_counts[sops[0].sem_num]--;
220+
return0;
221+
}elseif (ret==WAIT_TIMEOUT)
222+
/* Couldn't get it */
223+
errno=EAGAIN;
224+
else
225+
errno=EIDRM;
226+
}
227+
elseif (sops[0].sem_op>0) {
228+
/* Don't want the lock anymore */
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sem_counts[sops[0].sem_num]++;
230+
ReleaseSemaphore(cur_handle,sops[0].sem_op,NULL);
231+
return0;
232+
}
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else
234+
/* Not supported */
235+
errno=ERANGE;
236+
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/* If we get down here, then something is wrong */
238+
return-1;
239+
}

‎src/backend/port/win32/shm.c

Lines changed: 120 additions & 0 deletions
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/*-------------------------------------------------------------------------
2+
*
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* shm.c
4+
* Microsoft Windows Win32 Shared Memory Emulation
5+
*
6+
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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*
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*-------------------------------------------------------------------------
9+
*/
10+
11+
#include"postgres.h"
12+
#include"windows.h"
13+
14+
#include<stdio.h>
15+
#include<errno.h>
16+
17+
staticDWORDs_segsize=0;
18+
19+
/* Detach from a shared mem area based on its address */
20+
int
21+
shmdt(constvoid*shmaddr)
22+
{
23+
if (UnmapViewOfFile(shmaddr))
24+
return0;
25+
else
26+
return-1;
27+
}
28+
29+
/* Attach to an existing area */
30+
void*
31+
shmat(intmemId,void*shmaddr,intflag)
32+
{
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/* KEW_TODO -- shmat needs to count # attached to shared mem */
34+
void*lpmem=MapViewOfFileEx((HANDLE)memId,
35+
FILE_MAP_WRITE |FILE_MAP_READ,
36+
0,0,/* (DWORD)pshmdsc->segsize */s_segsize,shmaddr);
37+
38+
if (lpmem==NULL) {
39+
lpmem= (void*)-1;
40+
errno=GetLastError();
41+
}
42+
43+
returnlpmem;
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}
45+
46+
/* Control a shared mem area */
47+
int
48+
shmctl(intshmid,intflag,structshmid_ds*dummy)
49+
{
50+
if (flag==IPC_RMID)
51+
{
52+
/* Delete the area */
53+
CloseHandle((HANDLE)shmid);
54+
return0;
55+
}
56+
if (flag==IPC_STAT)
57+
{
58+
/* Can only test for if exists */
59+
inthmap=shmget(shmid,0,0);
60+
if (hmap<0) {
61+
/* Shared memory does not exist */
62+
errno=EINVAL;
63+
return-1;
64+
}
65+
else {
66+
/* Shared memory does exist and must be in use */
67+
shmctl(hmap,IPC_RMID,NULL);/* Release our hold on it */
68+
errno=0;
69+
return0;
70+
}
71+
}
72+
73+
errno=EINVAL;
74+
return-1;
75+
}
76+
77+
/* Get an area based on the IPC key */
78+
int
79+
shmget(intmemKey,intsize,intflag)
80+
{
81+
HANDLEhmap;
82+
charszShareMem[32];
83+
DWORDdwRet;
84+
85+
s_segsize=size;
86+
sprintf(szShareMem,"sharemem.%d",memKey);
87+
88+
if (flag&IPC_CREAT) {
89+
hmap=CreateFileMapping((HANDLE)0xFFFFFFFF,/* Use the swap file */
90+
NULL,
91+
PAGE_READWRITE,/* Memory is Read/Write */
92+
0L,/* Size Upper 32 Bits */
93+
(DWORD)s_segsize,/* Size Lower 32 bits*/
94+
szShareMem);
95+
}
96+
else {
97+
hmap=OpenFileMapping(FILE_MAP_ALL_ACCESS,
98+
FALSE,
99+
szShareMem);
100+
if (!hmap) {
101+
errno=ENOENT;
102+
return-1;
103+
}
104+
}
105+
106+
dwRet=GetLastError();
107+
if (dwRet==ERROR_ALREADY_EXISTS&&hmap&& (flag& (IPC_CREAT |IPC_EXCL))) {
108+
/* Caller wanted to create the segment -- error if already exists */
109+
CloseHandle(hmap);
110+
errno=EEXIST;
111+
return-1;
112+
}
113+
elseif (!hmap)
114+
{
115+
/* Unable to get shared memory */
116+
return-1;
117+
}
118+
119+
return (int)hmap;
120+
}

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