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Diffstat (limited to 'src/libs/xpcom18a4/nsprpub/pr/include/prshma.h')
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1 files changed, 279 insertions, 0 deletions
diff --git a/src/libs/xpcom18a4/nsprpub/pr/include/prshma.h b/src/libs/xpcom18a4/nsprpub/pr/include/prshma.h new file mode 100644 index 00000000..0214e0aa --- /dev/null +++ b/src/libs/xpcom18a4/nsprpub/pr/include/prshma.h @@ -0,0 +1,279 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * 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 Netscape Portable Runtime (NSPR). + * + * The Initial Developer of the Original Code is + * Netscape Communications Corporation. + * Portions created by the Initial Developer are Copyright (C) 1999-2000 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * + * Alternatively, the contents of this file may be used under the terms of + * either the GNU General Public License Version 2 or later (the "GPL"), or + * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +/* +** prshma.h -- NSPR Anonymous Shared Memory +** +** NSPR provides an anonymous shared memory based on NSPR's PRFileMap +** type. The anonymous file-mapped shared memory provides an inheritable +** shared memory, as in: the child process inherits the shared memory. +** Compare the file-mapped anonymous shared memory to to a named shared +** memory described in prshm.h. The intent is to provide a shared +** memory that is accessable only by parent and child processes. ... +** It's a security thing. +** +** Depending on the underlying platform, the file-mapped shared memory +** may be backed by a file. ... surprise! ... On some platforms, no +** real file backs the shared memory. On platforms where the shared +** memory is backed by a file, the file's name in the filesystem is +** visible to other processes for only the duration of the creation of +** the file, hopefully a very short time. This restricts processess +** that do not inherit the shared memory from opening the file and +** reading or writing its contents. Further, when all processes +** using an anonymous shared memory terminate, the backing file is +** deleted. ... If you are not paranoid, you're not paying attention. +** +** The file-mapped shared memory requires a protocol for the parent +** process and child process to share the memory. NSPR provides two +** protocols. Use one or the other; don't mix and match. +** +** In the first protocol, the job of passing the inheritable shared +** memory is done via helper-functions with PR_CreateProcess(). In the +** second protocol, the parent process is responsible for creating the +** child process; the parent and child are mutually responsible for +** passing a FileMap string. NSPR provides helper functions for +** extracting data from the PRFileMap object. ... See the examples +** below. +** +** Both sides should adhere strictly to the protocol for proper +** operation. The pseudo-code below shows the use of a file-mapped +** shared memory by a parent and child processes. In the examples, the +** server creates the file-mapped shared memory, the client attaches to +** it. +** +** First protocol. +** Server: +** +** fm = PR_OpenAnonFileMap(dirName, size, FilemapProt); +** addr = PR_MemMap(fm); +** attr = PR_NewProcessAttr(); +** PR_ProcessAttrSetInheritableFileMap( attr, fm, shmname ); +** PR_CreateProcess(Client); +** PR_DestroyProcessAttr(attr); +** ... yadda ... +** PR_MemUnmap( addr ); +** PR_CloseFileMap(fm); +** +** +** Client: +** ... started by server via PR_CreateProcess() +** fm = PR_GetInheritedFileMap( shmname ); +** addr = PR_MemMap(fm); +** ... yadda ... +** PR_MemUnmap(addr); +** PR_CloseFileMap(fm); +** +** +** Second Protocol: +** Server: +** +** fm = PR_OpenAnonFileMap(dirName, size, FilemapProt); +** fmstring = PR_ExportFileMapAsString( fm ); +** addr = PR_MemMap(fm); +** ... application specific technique to pass fmstring to child +** ... yadda ... Server uses his own magic to create child +** PR_MemUnmap( addr ); +** PR_CloseFileMap(fm); +** +** +** Client: +** ... started by server via his own magic +** ... application specific technique to find fmstring from parent +** fm = PR_ImportFileMapFromString( fmstring ) +** addr = PR_MemMap(fm); +** ... yadda ... +** PR_MemUnmap(addr); +** PR_CloseFileMap(fm); +** +** +** lth. 2-Jul-1999. +** +** Note: The second protocol was requested by NelsonB (7/1999); this is +** to accomodate servers which already create their own child processes +** using platform native methods. +** +*/ + +#ifndef prshma_h___ +#define prshma_h___ + +#include "prtypes.h" +#include "prio.h" +#include "prproces.h" + +#ifdef VBOX_WITH_XPCOM_NAMESPACE_CLEANUP +#define PR_OpenAnonFileMap VBoxNsprPR_OpenAnonFileMap +#define PR_ProcessAttrSetInheritableFileMap VBoxNsprPR_ProcessAttrSetInheritableFileMap +#define PR_GetInheritedFileMap VBoxNsprPR_GetInheritedFileMap +#define PR_ExportFileMapAsString VBoxNsprPR_ExportFileMapAsString +#define PR_ImportFileMapFromString VBoxNsprPR_ImportFileMapFromString +#endif /* VBOX_WITH_XPCOM_NAMESPACE_CLEANUP */ + +PR_BEGIN_EXTERN_C + +/* +** PR_OpenAnonFileMap() -- Creates an anonymous file-mapped shared memory +** +** Description: +** PR_OpenAnonFileMap() creates an anonymous shared memory. If the +** shared memory already exists, a handle is returned to that shared +** memory object. +** +** On Unix platforms, PR_OpenAnonFileMap() uses 'dirName' as a +** directory name, without the trailing '/', to contain the anonymous +** file. A filename is generated for the name. +** +** On Windows platforms, dirName is ignored. +** +** Inputs: +** dirName -- A directory name to contain the anonymous file. +** size -- The size of the shared memory +** prot -- How the shared memory is mapped. See prio.h +** +** Outputs: +** PRFileMap * +** +** Returns: +** Pointer to PRFileMap or NULL on error. +** +*/ +NSPR_API( PRFileMap *) +PR_OpenAnonFileMap( + const char *dirName, + PRSize size, + PRFileMapProtect prot +); + +/* +** PR_ProcessAttrSetInheritableFileMap() -- Prepare FileMap for export +** to my children processes via PR_CreateProcess() +** +** Description: +** PR_ProcessAttrSetInheritableFileMap() connects the PRFileMap to +** PRProcessAttr with shmname. A subsequent call to PR_CreateProcess() +** makes the PRFileMap importable by the child process. +** +** Inputs: +** attr -- PRProcessAttr, used to pass data to PR_CreateProcess() +** fm -- PRFileMap structure to be passed to the child process +** shmname -- The name for the PRFileMap; used by child. +** +** Outputs: +** PRFileMap * +** +** Returns: +** PRStatus +** +*/ +NSPR_API(PRStatus) +PR_ProcessAttrSetInheritableFileMap( + PRProcessAttr *attr, + PRFileMap *fm, + const char *shmname +); + +/* +** PR_GetInheritedFileMap() -- Import a PRFileMap previously exported +** by my parent process via PR_CreateProcess() +** +** Description: +** PR_GetInheritedFileMap() retrieves a PRFileMap object exported from +** its parent process via PR_CreateProcess(). +** +** Inputs: +** shmname -- The name provided to PR_ProcessAttrSetInheritableFileMap() +** +** Outputs: +** PRFileMap * +** +** Returns: +** PRFileMap pointer or NULL. +** +*/ +NSPR_API( PRFileMap *) +PR_GetInheritedFileMap( + const char *shmname +); + +/* +** PR_ExportFileMapAsString() -- Creates a string identifying a PRFileMap +** +** Description: +** Creates an identifier, as a string, from a PRFileMap object +** previously created with PR_OpenAnonFileMap(). +** +** Inputs: +** fm -- PRFileMap pointer to be represented as a string. +** bufsize -- sizeof(buf) +** buf -- a buffer of length PR_FILEMAP_STRING_BUFSIZE +** +** Outputs: +** buf contains the stringized PRFileMap identifier +** +** Returns: +** PRStatus +** +*/ +NSPR_API( PRStatus ) +PR_ExportFileMapAsString( + PRFileMap *fm, + PRSize bufsize, + char *buf +); +#define PR_FILEMAP_STRING_BUFSIZE 128 + +/* +** PR_ImportFileMapFromString() -- Creates a PRFileMap from the identifying string +** +** Description: +** PR_ImportFileMapFromString() creates a PRFileMap object from a +** string previously created by PR_ExportFileMapAsString(). +** +** Inputs: +** fmstring -- string created by PR_ExportFileMapAsString() +** +** Returns: +** PRFileMap pointer or NULL. +** +*/ +NSPR_API( PRFileMap * ) +PR_ImportFileMapFromString( + const char *fmstring +); + +PR_END_EXTERN_C +#endif /* prshma_h___ */ |