boinc/lib/shmem.C

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// The contents of this file are subject to the BOINC Public License
// Version 1.0 (the "License"); you may not use this file except in
// compliance with the License. You may obtain a copy of the License at
// http://boinc.berkeley.edu/license_1.0.txt
//
// Software distributed under the License is distributed on an "AS IS"
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
// License for the specific language governing rights and limitations
// under the License.
//
// The Original Code is the Berkeley Open Infrastructure for Network Computing.
//
// The Initial Developer of the Original Code is the SETI@home project.
// Portions created by the SETI@home project are Copyright (C) 2002
// University of California at Berkeley. All Rights Reserved.
//
// Contributor(s):
//
// interfaces for accessing shared memory segments
#include <stdio.h>
#include <string.h>
#ifdef _WIN32
#include <windows.h>
#endif
#include <sys/types.h>
#if HAVE_SYS_IPC_H
#include <sys/ipc.h>
#endif
#if HAVE_SYS_SHM_H
#if __FreeBSD__
#include <sys/param.h>
#endif
#include <sys/shm.h>
#endif
#include <assert.h>
#include "error_numbers.h"
#include "shmem.h"
#ifdef _WIN32
HANDLE create_shmem(LPCTSTR seg_name, int size, void** pp) {
SECURITY_ATTRIBUTES security;
HANDLE hSharedMem;
LPVOID pMemPtr;
security.nLength = sizeof(security);
security.lpSecurityDescriptor = NULL;
security.bInheritHandle = TRUE;
hSharedMem = CreateFileMapping(INVALID_HANDLE_VALUE, &security,
PAGE_READWRITE, 0, size, seg_name);
if (!hSharedMem) return NULL;
pMemPtr = MapViewOfFile( hSharedMem, FILE_MAP_ALL_ACCESS, 0, 0, 0 );
*pp = pMemPtr;
return hSharedMem;
}
HANDLE attach_shmem(LPCTSTR seg_name, void** pp) {
HANDLE hSharedMem;
LPVOID pMemPtr;
hSharedMem = OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, seg_name);
if (!hSharedMem) return NULL;
pMemPtr = MapViewOfFile( hSharedMem, FILE_MAP_ALL_ACCESS, 0, 0, 0 );
*pp = pMemPtr;
return hSharedMem;
}
int detach_shmem(HANDLE hSharedMem, void* p) {
UnmapViewOfFile(p);
CloseHandle(hSharedMem);
return 0;
}
#else
int create_shmem(key_t key, int size, void** pp) {
int id;
char buf[256];
assert(pp!=NULL);
id = shmget(key, size, IPC_CREAT|0777);
if (id < 0) {
sprintf(buf, "create_shmem: shmget: key: %x size: %d", (unsigned int)key, size);
perror(buf);
return ERR_SHMGET;
}
return attach_shmem(key, pp);
}
int destroy_shmem(key_t key){
struct shmid_ds buf;
int id, retval;
id = shmget(key, 0, 0);
if (id < 0) return 0; // assume it doesn't exist
retval = shmctl(id, IPC_STAT, &buf);
if (retval) return ERR_SHMCTL;
if (buf.shm_nattch > 0) {
fprintf(stderr,
"destroy_shmem: can't destroy segment; %d attachments\n",
(int)buf.shm_nattch
);
return ERR_SHMCTL;
}
retval = shmctl(id, IPC_RMID, 0);
if (retval) {
fprintf(stderr, "destroy_shmem: remove failed %d\n", retval);
return ERR_SHMCTL;
}
return 0;
}
int attach_shmem(key_t key, void** pp){
void* p;
char buf[256];
int id;
assert(pp!=NULL);
id = shmget(key, 0, 0);
if (id < 0) {
sprintf(buf, "attach_shmem: shmget: key: %x mem_addr: %p", (unsigned int)key, (void*)pp);
perror(buf);
return ERR_SHMGET;
}
p = shmat(id, 0, 0);
if ((long)p == ERR_SHMAT) {
sprintf(buf, "attach_shmem: shmat: key: %x mem_addr: %p", (unsigned int)key, (void*)pp);
perror(buf);
return ERR_SHMAT;
}
*pp = p;
return 0;
}
int detach_shmem(void* p) {
int retval;
assert(p!=NULL);
retval = shmdt((char *)p);
if (retval) perror("detach_shmem: shmdt");
return retval;
}
int shmem_info(key_t key) {
int id;
struct shmid_ds buf;
char buf2[256];
id = shmget(key, 0, 0);
if (id < 0) {
sprintf(buf2, "shmem_info: shmget: key: %x", (unsigned int)key);
perror(buf2);
return ERR_SHMGET;
}
shmctl(id, IPC_STAT, &buf);
fprintf( stderr, "shmem key: %x\t\tid: %d, size: %d, nattach: %d\n",
(unsigned int)key, id, buf.shm_segsz, (int)buf.shm_nattch );
return 0;
}
#endif