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Fixed work with Shared Memory on Windows. #17273

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Fixed work with Shared Memory on Windows. #17273

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f51a238
Fixed work with Shared Memory on Windows.
Dec 26, 2024
eddb03e
Update tsrm_win32.c
CoderAImen Dec 27, 2024
0f57e0c
Update tsrm_win32.c
CoderAImen Dec 27, 2024
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30 changes: 25 additions & 5 deletions TSRM/tsrm_win32.c
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Original file line number Diff line number Diff line change
Expand Up @@ -688,8 +688,19 @@ TSRM_API int shmget(key_t key, size_t size, int flags)
CloseHandle(shm_handle);
return -1;
}
shm->segment = shm_handle;
shm->descriptor = MapViewOfFileEx(shm->segment, FILE_MAP_ALL_ACCESS, 0, 0, 0, NULL);
if (NULL == shm->segment || INVALID_HANDLE_VALUE == shm->segment) {
shm->segment = shm_handle;
shm->created = created;
}
else if (TRUE == created) {
CloseHandle(shm->segment);
shm->segment = shm_handle;
shm->created = TRUE;
}
Comment on lines +695 to +699
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I don't understand what would be special about created. We either use OpenFileMapping() or CreateFileMapping() to get the shm_handle, and it seems to me that we want to close the shm->segment in neither case.

else {
CloseHandle(shm_handle);
}
if(NULL == shm->descriptor)shm->descriptor = MapViewOfFileEx(shm->segment, FILE_MAP_ALL_ACCESS, 0, 0, 0, NULL);

if (NULL != shm->descriptor && created) {
shm->descriptor->shm_perm.key = key;
Expand Down Expand Up @@ -730,6 +741,7 @@ TSRM_API void *shmat(int key, const void *shmaddr, int flags)
shm->descriptor->shm_atime = time(NULL);
shm->descriptor->shm_lpid = getpid();
shm->descriptor->shm_nattch++;
shm->shm_nattch++;

return shm->addr;
}/*}}}*/
Expand All @@ -746,12 +758,20 @@ TSRM_API int shmdt(const void *shmaddr)
shm->descriptor->shm_dtime = time(NULL);
shm->descriptor->shm_lpid = getpid();
shm->descriptor->shm_nattch--;
shm->shm_nattch--;

ret = 0;
if (shm->descriptor->shm_nattch <= 0) {
ret = UnmapViewOfFile(shm->descriptor) ? 0 : -1;
shm->descriptor = NULL;
if (shm->shm_nattch <= 0) {
shm->shm_nattch = 0;
if (NULL != shm->segment && INVALID_HANDLE_VALUE != shm->segment && FALSE == shm->created) {
if(NULL != shm->descriptor)ret = UnmapViewOfFile(shm->descriptor) ? 0 : -1;
shm->descriptor = NULL;
CloseHandle(shm->segment);
shm->segment = INVALID_HANDLE_VALUE;
shm->addr = NULL;
}
}

return ret;
}/*}}}*/

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2 changes: 2 additions & 0 deletions TSRM/tsrm_win32.h
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Expand Up @@ -51,6 +51,8 @@ typedef struct {
typedef struct {
void *addr;
HANDLE segment;
BOOL created;
int shm_nattch;
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Okay, I see that we need to track the number of attachments for each process/thread, so that we're able to close the file handle per process/thread when we're done with the SHM.

struct shmid_ds *descriptor;
} shm_pair;

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