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关于流文件对象
来这里问了几个问题，得不到解决，只好上OSR上问，感兴趣的朋友瞧瞧，希望跟我有同样困惑的朋友能得到帮助
http://www.osronline.com/cf.cfm?PageURL=showlists.CFM?list=NTFSD 标题是：questions about the stream file object 08 Apr 09 22:46 cai yuqing xxxxxx@21cn.com Join Date: 08 Apr 2009 Posts To This List: 4 questions about the stream file object -------------------------------------------------------------------------------- Hi,Dear all :) I have some questions about the stream file object,hope somebody can help me.... 1. In what situation that system will create a stream file object? Does it mean when user application use C++'s iostream operation will cause this happen? 2. what's the different between a stream file object and a normal file object? 3. MSDN mention that when a stream file object created, It does not send a IRP_MJ_CREATE IRP but a IRP_MJ_CLEANUP IRP,in this case,how do we catch this file create operation in our filter? Message 2 of 8 Yesterday 08:44 Peter Scott xxxxxx@KernelDrivers.com Join Date: 14 Jan 2002 Posts To This List: 333 Re: questions about the stream file object -------------------------------------------------------------------------------- xxxxx@21cn.com wrote: > Hi,Dear all :) > > I have some questions about the stream file object,hope somebody can help me.... > > 1. In what situation that system will create a stream file object? Does it mean when user application use C++'s iostream operation will cause this happen? Other kernel mode components can use stream file objects in a wide range of designs. NTFS uses SFO's for cache map initialization, hence you see paging coming in against a SFO. > 2. what's the different between a stream file object and a normal file object? The difference is that you have not seen an IRP_MJ_CREATE for the file object and the FO_STREAM_FILE_OBJECT Flag is set. Other than that they can be used for any operation that comes through the file system stack. > 3. MSDN mention that when a stream file object created, It does not send a IRP_MJ_CREATE IRP but a IRP_MJ_CLEANUP IRP,in this case,how do we catch this file create operation in our filter? > You can not capture the creation of these through standard mechanisms. You do need to recognize the tear down of these during IRP_MJ_CLEANUP and CLOSE processing though. Have you read the reference counting article at OSR Online? This discusses how to make sure your counts are correct. Of course, with Filter Manager you don't need to worry about them from the perspective of reference counting. Pete > --- > NTFSD is sponsored by OSR > > For our schedule of debugging and file system seminars > (including our new fs mini-filter seminar) visit: > http://www.osr.com/seminars > > To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer -- Kernel Drivers Windows File System and Device Driver Consulting www.KernelDrivers.com 866.263.9295 Message 3 of 8 Yesterday 09:44 cai yuqing xxxxxx@21cn.com Join Date: 08 Apr 2009 Posts To This List: 4 RE: questions about the stream file object -------------------------------------------------------------------------------- Pete,thanks for your reply: ) I am a new guy in filter developing,can you give me the link about the reference counting article at OSR Online? Message 4 of 8 Yesterday 09:51 MM xxxxxx@evitechnology.com Join Date: 28 May 2005 Posts To This List: 260 Re: questions about the stream file object -------------------------------------------------------------------------------- I imagine that this is it: http://www.osronline.com/article.cfm?id=102 xxxxx@21cn.com wrote: > Pete,thanks for your reply: ) > I am a new guy in filter developing,can you give me the link about the reference counting article at OSR Online? > > Message 5 of 8 Yesterday 09:58 cai yuqing xxxxxx@21cn.com Join Date: 08 Apr 2009 Posts To This List: 4 RE: questions about the stream file object -------------------------------------------------------------------------------- by the way Pete,can you give me links about stream file object, I should learn more about it, thanks Message 6 of 8 Yesterday 10:25 Peter Scott xxxxxx@KernelDrivers.com Join Date: 14 Jan 2002 Posts To This List: 333 Re: questions about the stream file object -------------------------------------------------------------------------------- xxxxx@21cn.com wrote: > by the way Pete,can you give me links about stream file object, I should learn more about it, thanks > I would read up on the WDK docs about the IoCreateStreamFileObject(), IoCreateStreamFileObjectEx() and IoCreateStreamFileObjectLite(). They each offer slightly different functionality but do give information on what they can be used for. Other than that, search for the APIs in the FAT source code and follow how they are used. Pete > --- > NTFSD is sponsored by OSR > > For our schedule of debugging and file system seminars > (including our new fs mini-filter seminar) visit: > http://www.osr.com/seminars > > To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer -- Kernel Drivers Windows File System and Device Driver Consulting www.KernelDrivers.com 866.263.9295 Message 7 of 8 Yesterday 11:02 cai yuqing xxxxxx@21cn.com Join Date: 08 Apr 2009 Posts To This List: 4 RE: questions about the stream file object -------------------------------------------------------------------------------- copy that~:) Message 8 of 8 Yesterday 17:32 Maxim S. Shatskih xxxxxx@storagecraft.com Join Date: 23 Feb 2000 Posts To This List: 3136 Re: questions about the stream file object -------------------------------------------------------------------------------- > 1. In what situation that system will create a stream file object? Does it mean when user application >use C++'s iostream operation will cause this happen? No for sure. C++ streams are the wrappers around the CRT's read/write/open/creat/close, and they are - in Windows - in turn wrappers over kernel32!CreateFile/ReadFile, which are in turn wrappers over ntdll!NtCreateFile/NtReadFile syscalls going down to the kernel. Stream file object is the file object handicrafted _by the FSD itself_ without going thru the usual kernel's IoCreateFile path. The purpose of such file objects are at FSD's developer will, but usually they are used to create the cache maps and thus cache some metadata. For instance, FASTFAT uses such object to cache FAT and the FAT12/16 root dir. -- Maxim S. Shatskih Windows DDK MVP xxxxx@storagecraft.com http://www.storagecraft.com |
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