February 2005 - Darwin-kernel

Re: shm_open and mmap: Invalid argument?
by Tim Hewett 21 Feb '05

21 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Ethan, On 21 Feb 2005, at 06:21, Ethan Tira-Thompson wrote: When your processes attach to the shared region how do they know the size? Is it an application-wide constant? The call to mmap has to have the size (since you can choose not to map all the region). I've found that fstat() gets it fine on an inherited shared memory descriptor from the parent. It is beginning to look like my approach with shm_unlink is going to be a problem. My circumstance is that a controlling process creates the shared segment and spawns short-lived children which use the shared segment. Those children ought to be able to use the inherited file descriptor that the parent received from shm_open() when creating the region. They ought not to have to call shm_open() themselves to attach to the region, and so the region ought not to have to exist in its name space (is there a "shm_ls" feature so you can see what's in the name space??). This should mean that the process creating the region can unlink it immediately and just use common inheritance for subprocesses to attach to it. The shm_open man page certainly suggests that this should be possible, i.e. "The new descriptor is set to remain open across execve system calls" (though it directly contradicts itself earlier stating "The new file descriptor will have the FD_CLOEXEC flag set") but this suggests inheritability of the file descriptor and it would be natural for that to happen anyway. In my case the file descriptor has the FD_CLOEXEC flag set on it explicitly immediately after its creation, so that it isn't inherited across exec unnecessarily, however for the children that use the shared region this descriptor is dup'd, which implicitly causes this flag to be cleared. The descriptor is definitely being inherited across exec anyway since the call to fstat() on it is successful and returns expected results. It is the mmap() which is the problem returning EINVAL, and it seems to me that this is not what should happen. [large chunk snipped] Regards, Tim. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… Thanks to everyone for their insight... I've gotten things working, but there may be more here for you to work on amongst yourselves (assuming there's a few kernel hackers on here...) Actually, I think documentation or a code sample was the real shortcoming, and that's not limited to Darwin (I did extensive web searching before winding up here) So, ftruncate does seem to be key in the creation of a shared memory region - after shm_open, before mmap. However, it should only be called on a *new* region at its creation... it will return an error if you're connecting to a pre-existing region. That seems reasonable enough, but I found this aspect to be rather undocumented. (I suppose the size/len argument of mmap is supposed to be used to map a subsection of a file into memory, so you have to use ftruncate to pre-size the shared memory region, and then can selectively map portions of the region into the process. I initially expected mmap to do the region sizing itself...) The next step is shm_unlink. It seems it should *not* be called right after the creation in order to request dereference down the road (i.e. shm_open, ftruncate, mmap, close, shm_unlink) shm_unlink will remove the name immediately, thus blocking other processes from accessing it since it's on the way out. However, I suppose it's fine to call immediately following the last attach you are expecting, to guarantee that a sudden crash will cause it to be removed. The safest general behavior (if you don't know when an attach is the last one) seems to be to wait until the last reference is being removed, and then call shm_unlink. This is directly analogous to using shmctl to delete a region under SysV. (initially I had called it on *every* dereference, so I'm not completely sure what happens if it's not called for the last dereference, or if I the errors I got were for the first call or the last call (i.e. did the first call succeed and following ones fail, or did all fail except the last?)) This brings up an interesting problem however. If you shm_open a bunch of regions, and never unlink them, where do they go when the process gets shutdown? My experience from the intial email implies they stick around (blocking further attempts to make new regions of the same name). Is there a system limit on these resources? Is it possible to get a list of current regions? Is it possible to clean them out without rebooting (yes if we can get the list of names, but otherwise...)? I could see some havoc being caused by a program which leaks regions, using random or unpredictable names, which can then never be reclaimed. Surely that's not the case? (say it ain't so!) It seems to me that the man page makes it clear that the shared memory will persist even when all processes using it have terminated. I figure that this means that the swap space will just go on getting bigger as more of these segments are left around. The man page mentions that the segments don't persist across a reboot though so there is a way out. I agree that it would be useful to see what exists to then have an opportunity to tidy up, but that doesn't appear to be possible. Hence why I want to have my region automatically removed when all processes detach from it (even if they crash) by calling shm_unlink as soon as the region is created and relying on inheritance of the descriptor (rather than the name of the region) to have the subprocesses attach. This email sent to site_archiver(a)lists.apple.com

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Re: shm_open and mmap: Invalid argument?
by Ethan Tira-Thompson 21 Feb '05

21 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com ACCESS: (from another process) shm_open mmap close REMOVAL: (when done) munmap if(wasLastReference) shm_unlink; Thanks! -ethan _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… Thanks to everyone for their insight... I've gotten things working, but there may be more here for you to work on amongst yourselves (assuming there's a few kernel hackers on here...) Actually, I think documentation or a code sample was the real shortcoming, and that's not limited to Darwin (I did extensive web searching before winding up here) So, ftruncate does seem to be key in the creation of a shared memory region - after shm_open, before mmap. However, it should only be called on a *new* region at its creation... it will return an error if you're connecting to a pre-existing region. That seems reasonable enough, but I found this aspect to be rather undocumented. (I suppose the size/len argument of mmap is supposed to be used to map a subsection of a file into memory, so you have to use ftruncate to pre-size the shared memory region, and then can selectively map portions of the region into the process. I initially expected mmap to do the region sizing itself...) The next step is shm_unlink. It seems it should *not* be called right after the creation in order to request dereference down the road (i.e. shm_open, ftruncate, mmap, close, shm_unlink) shm_unlink will remove the name immediately, thus blocking other processes from accessing it since it's on the way out. However, I suppose it's fine to call immediately following the last attach you are expecting, to guarantee that a sudden crash will cause it to be removed. The safest general behavior (if you don't know when an attach is the last one) seems to be to wait until the last reference is being removed, and then call shm_unlink. This is directly analogous to using shmctl to delete a region under SysV. (initially I had called it on *every* dereference, so I'm not completely sure what happens if it's not called for the last dereference, or if I the errors I got were for the first call or the last call (i.e. did the first call succeed and following ones fail, or did all fail except the last?)) This brings up an interesting problem however. If you shm_open a bunch of regions, and never unlink them, where do they go when the process gets shutdown? My experience from the intial email implies they stick around (blocking further attempts to make new regions of the same name). Is there a system limit on these resources? Is it possible to get a list of current regions? Is it possible to clean them out without rebooting (yes if we can get the list of names, but otherwise...)? I could see some havoc being caused by a program which leaks regions, using random or unpredictable names, which can then never be reclaimed. Surely that's not the case? (say it ain't so!) For the region names, it doesn't seem to matter if they start with a '/' or not. I'm not going to bother for now, I'll write back if I run into portability issues on other platforms. I haven't checked if it's a problem if a file has the same name. (implied by #2 from Tim?) Thus, for future reference, correct (or at least functional) usage appears to be: CREATION: (initial setup) shm_open ftruncate mmap close My OS is 10.3.8 My code for this can be found at: http://cvs.tekkotsu.org/cgi-bin/viewcvs.cgi/Tekkotsu/Shared/Attic/ RCRegion.cc?rev=1.1.2.4&content-type=text/vnd.viewcvs-markup This class contains code for either SysV or POSIX style shared memory, and can be switched back and forth using a #define. (TEKKOTSU_SHM_STYLE set to either SYSV_SHM or POSIX_SHM) This is part of a framework for robotics software, which currently runs on the Sony Aibo, but we are trying to port to desktop computers for local development and simulation. The Aibo uses processes with shared memory regions for communication, and in order to allow the most accurate local simulation possible, we are doing the same for the desktop. (threads would've been a little easier to port initially, but would wind up sharing global values, not just specified objects, leading to different behavior between code on the desktop and code on the actual robot. In general, this architecture actually seems quite nice for preventing unanticipated interaction between different threads of execution, but still allowing full interaction in specified key shared regions.) This email sent to site_archiver(a)lists.apple.com

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Re: Reserving the Disk Space
by William Kucharski 21 Feb '05

21 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Feb 20, 2005, at 10:53 PM, Imran wrote: William Kucharski kucharsk(a)mac.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… Does HFS+ file system under Darwin XNU provide such API to reserve the disk space of GB’s? Well, the file system will ALWAYS be "aware" of it, but the way to make it "invisible" is to open a file descriptor to it and unlink it while the file is still open. In this way you can access the file on disk but traversing the directory structure will not reveal your file's existence. This email sent to site_archiver(a)lists.apple.com

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Reserving the Disk Space
by Imran 21 Feb '05

21 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: AcUX2atdgcITHThZS8G5wcw1AVxFpQ== _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: shm_open and mmap: Invalid argument?
by Tim Hewett 21 Feb '05

21 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Mark, It looks like off_t casting is a red herring, I deleted the cast in mine and it still worked ok. Now that I know about the Posix shm_open() call (thanks to this thread) I am now experimenting with it, for Ethan's benefit here are the results as they seem to be different to what he reports: 1. For the process initially creating the shared memory, the shm_open() works and the mmap() works (no "Invalid argument" error). I had been calling shm_unlink() right after the shm_open() call, so that the shared memory is always deleted after the last process using it terminates (even if it crashes) but that was failing with EINVAL. It was moved to after the mmap() and now works. That doesn't make much sense but that is how it is, it seems as if Posix shared memory is in some kind of limbo state meaning it can't be unlinked until after it has been mapped. This is my experimental code: Parent process (shared memory creator) - works fine: if ( (bufferFd = shm_open( "/1", O_RDWR | O_CREAT, 0700 )) == -1 ) { // Error handling here return; } if ( fcntl( bufferFd, F_SETFD, 1 ) == -1 ) { // Error handling here } if ( ftruncate( bufferFd, (off_t)size ) == -1 ) { // Error handling here return; } if ( (buf = mmap( NULL, (size_t)size, PROT_READ | PROT_WRITE, MAP_SHARED, bufferFd, 0 )) == (void *)-1 ) { // Error handling here return; } if ( mlock( (caddr_t)buf, (size_t)size ) == -1 ) { // Error handling here return; } if ( shm_unlink( "/1" ) == -1 ) { // Error handling here } Child process - inherits shared memory file descriptor, mmap() returns EINVAL but the preceding call to fstat() works fine so the descriptor is being inherited ok (not much else can be wrong): if ( fstat( inherited_fd, &filestat ) == -1 ) { // Error handling here exit( -1 ); } if ( (buf = mmap( NULL, filestat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, inherited_fd, (off_t)0 )) == (void *)-1 ) { // Error handling here exit( -1 ); } So this has kind of moved things along slightly, in that the creator can shm_open/fcntl/ftruncate/mmap/mlock/shm_unlink the shared memory, but the children can't mmap it yet even though they have successfully inherited the descriptor. My OS is 10.3.8 incidentally, not tried 10.2 yet. Tim. On 20 Feb 2005, at 20:42, Mark Williamson wrote: It looks like the final parameter to mmap() (i.e. an integer constant of value 0) needs to be cast to type off_t to suit the mmap function definition. The off_t type is a 64 bit "long long" while your constant is 32 bits, Lord only knows what'll be in the other 32 bits received by mmap()... Cheers, Mark HTH, Tim. What's going on? Thank you for your time! -ethan _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I am using mmap() on a real file, my shared memory is file-backed. This is because the System V IPC is not great under OS X in my experience and using file-backed shared memory seemed the only option for the size of shared memory I need. System V IPC semaphores were/(are?) the worst, under 10.2 they caused a dual CPU Mac to panic every time, it seems to be well worth avoiding the subsystem and use something a bit more universal. 2. If an ordinary file path is used for shm_open(), it fails. Changing the name to "/1" or similar makes it work fine. 3. The other processes sharing the shared memory in my application are all child processes and they mmap() it using the file descriptor they inherit from the main parent. Here I have the same problem as Ethan - the mmap always fails with EINVAL, why this only happens in the subprocesses is a mystery. Did this work for you? I thought that casts were supposed to be done automatically in these situations (assuming you included the right header files!!!). On 20 Feb 2005, at 20:03, darwin-kernel-request(a)lists.apple.com wrote: I am trying to implement some shared memory between a set of processes. I don't really care if it's file-backed or not -- these regions are not going to be particularly large, I just want low latency communication between the processes. I've already got things working with the SysV interfaces shmget and shmat, but Mac OS X is configured with a very low number of concurrently active regions per process (I think 8?) and I don't want other users to have to tinker with kernal configuration settings, so I'm switching to the POSIX interface instead. (It was also quite annoying that SysV regions are left in memory after all references are gone. Further, OS X doesn't provide the ipcs utility, I had to download it myself in order to kill the regions manually. (thanks to whoever ported that utility... I had trouble finding it the first time and I can't find it again now :( ) Anyway, now mmap always returns Invalid Argument when it is passed a file descriptor produced by shm_open. I saw somewhere that OS X/darwin doesn't support mmap with device files, does this imply no non-file backed regions? Further, calls to close() and shm_unlink() after the mmap error return Invalid Argument themselves, and then on the next run (using the same name) shm_open returns File Exists. So it appears the POSIX interface will also leave these regions floating around after the process ends and all references are removed, although I had read somewhere it wouldn't. (Especially annoying since I did make the calls to close and shm_unlink) Here's the code sample for the region in question: int fd; if(name.size()>=MAX_NAME_LEN) cerr << "*** WARNING RCRegion named " << name << " will be clipped to " << name.substr(0,MAX_NAME_LEN-2) << endl; id.key[0]='/'; //one page I read said for best portability, names should start with '/'... ? strncpy(id.key+1,name.c_str(),MAX_NAME_LEN-2); id.key[MAX_NAME_LEN-1]='\0'; cout << "Name is " << id.key << endl; if(create) { if((fd=shm_open(id.key,O_RDWR|O_CREAT|O_EXCL,0666))<0) { perror("Getting new region (shm_open)"); exit(EXIT_FAILURE); } } else { if((fd=shm_open(id.key,O_RDWR,0666))<0) { perror("Getting existing region (shm_open)"); exit(EXIT_FAILURE); } } cout << "fd is " << fd << endl; base=static_cast<char*>(mmap(NULL,sz,PROT_READ|PROT_WRITE,MAP_SHARED, fd , 0)); if (base == reinterpret_cast<char*>(-1)) { perror("Attaching region (mmap)"); if(close(fd)<0) perror("Warning: Closing temporary file descriptor from shm_open"); if(shm_unlink(id.key)<0) perror("Warning: Shared memory unlink (shm_unlink)"); exit(EXIT_FAILURE); } if(close(fd)<0) { perror("Warning: Closing temporary file descriptor from shm_open"); } _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/ mark.williamson%40cl.c am.ac.uk This email sent to mark.williamson(a)cl.cam.ac.uk This email sent to site_archiver(a)lists.apple.com

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Re: shm_open and mmap: Invalid argument?
by Tim Hewett 20 Feb '05

20 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Ethan, I think I've been here before, a while back. It looks like the final parameter to mmap() (i.e. an integer constant of value 0) needs to be cast to type off_t to suit the mmap function definition. The off_t type is a 64 bit "long long" while your constant is 32 bits, Lord only knows what'll be in the other 32 bits received by mmap()... HTH, Tim. On 20 Feb 2005, at 20:03, darwin-kernel-request(a)lists.apple.com wrote: I am trying to implement some shared memory between a set of processes. I don't really care if it's file-backed or not -- these regions are not going to be particularly large, I just want low latency communication between the processes. I've already got things working with the SysV interfaces shmget and shmat, but Mac OS X is configured with a very low number of concurrently active regions per process (I think 8?) and I don't want other users to have to tinker with kernal configuration settings, so I'm switching to the POSIX interface instead. (It was also quite annoying that SysV regions are left in memory after all references are gone. Further, OS X doesn't provide the ipcs utility, I had to download it myself in order to kill the regions manually. (thanks to whoever ported that utility... I had trouble finding it the first time and I can't find it again now :( ) Anyway, now mmap always returns Invalid Argument when it is passed a file descriptor produced by shm_open. I saw somewhere that OS X/darwin doesn't support mmap with device files, does this imply no non-file backed regions? Further, calls to close() and shm_unlink() after the mmap error return Invalid Argument themselves, and then on the next run (using the same name) shm_open returns File Exists. So it appears the POSIX interface will also leave these regions floating around after the process ends and all references are removed, although I had read somewhere it wouldn't. (Especially annoying since I did make the calls to close and shm_unlink) What's going on? Thank you for your time! -ethan _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… Here's the code sample for the region in question: int fd; if(name.size()>=MAX_NAME_LEN) cerr << "*** WARNING RCRegion named " << name << " will be clipped to " << name.substr(0,MAX_NAME_LEN-2) << endl; id.key[0]='/'; //one page I read said for best portability, names should start with '/'... ? strncpy(id.key+1,name.c_str(),MAX_NAME_LEN-2); id.key[MAX_NAME_LEN-1]='\0'; cout << "Name is " << id.key << endl; if(create) { if((fd=shm_open(id.key,O_RDWR|O_CREAT|O_EXCL,0666))<0) { perror("Getting new region (shm_open)"); exit(EXIT_FAILURE); } } else { if((fd=shm_open(id.key,O_RDWR,0666))<0) { perror("Getting existing region (shm_open)"); exit(EXIT_FAILURE); } } cout << "fd is " << fd << endl; base=static_cast<char*>(mmap(NULL,sz,PROT_READ|PROT_WRITE,MAP_SHARED,fd , 0)); if (base == reinterpret_cast<char*>(-1)) { perror("Attaching region (mmap)"); if(close(fd)<0) perror("Warning: Closing temporary file descriptor from shm_open"); if(shm_unlink(id.key)<0) perror("Warning: Shared memory unlink (shm_unlink)"); exit(EXIT_FAILURE); } if(close(fd)<0) { perror("Warning: Closing temporary file descriptor from shm_open"); } This email sent to site_archiver(a)lists.apple.com

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Re: shm_open and mmap: Invalid argument?
by Dan Bernstein 20 Feb '05

20 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:references; b=r9cPA+pIZpCRtoCXc8S2IE9HMuxmJA7lgIpRexjEp3/6NC4ieTr47eHNn9ZeNPBCNoD4NnuqKmt1hg0bhPPL2d/zlCeo1hRh0ReHNxvFd8YlQicRgRficYMdCSF/t8x7sdftk+LNqP+zH6++58RmP6XEfdd35KvsX8bUqkntJTs= If memory serves me right, you should call ftruncate(fd, sz) after calling shm_open and before calling mmap. -- Dan On Sun, 20 Feb 2005 14:51:43 -0500, Ethan Tira-Thompson <ejt(a)andrew.cmu.edu> wrote: > I am trying to implement some shared memory between a set of processes. > I don't really care if it's file-backed or not -- these regions are > not going to be particularly large, I just want low latency > communication between the processes. > > I've already got things working with the SysV interfaces shmget and > shmat, but Mac OS X is configured with a very low number of > concurrently active regions per process (I think 8?) and I don't want > other users to have to tinker with kernal configuration settings, so > I'm switching to the POSIX interface instead. (It was also quite > annoying that SysV regions are left in memory after all references are > gone. Further, OS X doesn't provide the ipcs utility, I had to > download it myself in order to kill the regions manually. (thanks to > whoever ported that utility... I had trouble finding it the first time > and I can't find it again now :( ) > > Anyway, now mmap always returns Invalid Argument when it is passed a > file descriptor produced by shm_open. I saw somewhere that OS X/darwin > doesn't support mmap with device files, does this imply no non-file > backed regions? Further, calls to close() and shm_unlink() after the > mmap error return Invalid Argument themselves, and then on the next run > (using the same name) shm_open returns File Exists. So it appears the > POSIX interface will also leave these regions floating around after the > process ends and all references are removed, although I had read > somewhere it wouldn't. (Especially annoying since I did make the calls > to close and shm_unlink) > > What's going on? > > Here's the code sample for the region in question: > int fd; > if(name.size()>=MAX_NAME_LEN) > cerr << "*** WARNING RCRegion named " << name << " will be clipped to > " << name.substr(0,MAX_NAME_LEN-2) << endl; > id.key[0]='/'; //one page I read said for best portability, names > should start with '/'... ? > strncpy(id.key+1,name.c_str(),MAX_NAME_LEN-2); > id.key[MAX_NAME_LEN-1]='\0'; > cout << "Name is " << id.key << endl; > if(create) { > if((fd=shm_open(id.key,O_RDWR|O_CREAT|O_EXCL,0666))<0) { > perror("Getting new region (shm_open)"); > exit(EXIT_FAILURE); > } > } else { > if((fd=shm_open(id.key,O_RDWR,0666))<0) { > perror("Getting existing region (shm_open)"); > exit(EXIT_FAILURE); > } > } > cout << "fd is " << fd << endl; > > base=static_cast<char*>(mmap(NULL,sz,PROT_READ|PROT_WRITE,MAP_SHARED,fd, > 0)); > if (base == reinterpret_cast<char*>(-1)) { > perror("Attaching region (mmap)"); > if(close(fd)<0) > perror("Warning: Closing temporary file descriptor from shm_open"); > if(shm_unlink(id.key)<0) > perror("Warning: Shared memory unlink (shm_unlink)"); > exit(EXIT_FAILURE); > } > if(close(fd)<0) { > perror("Warning: Closing temporary file descriptor from shm_open"); > } > > Thank you for your time! > -ethan > > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/darwin-kernel/dan.bernstein%40gmail.… > > This email sent to dan.bernstein(a)gmail.com > > _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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shm_open and mmap: Invalid argument?
by Ethan Tira-Thompson 20 Feb '05

20 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com int fd; if(name.size()>=MAX_NAME_LEN) cerr << "*** WARNING RCRegion named " << name << " will be clipped to " << name.substr(0,MAX_NAME_LEN-2) << endl; id.key[0]='/'; //one page I read said for best portability, names should start with '/'... ? strncpy(id.key+1,name.c_str(),MAX_NAME_LEN-2); id.key[MAX_NAME_LEN-1]='\0'; cout << "Name is " << id.key << endl; if(create) { if((fd=shm_open(id.key,O_RDWR|O_CREAT|O_EXCL,0666))<0) { perror("Getting new region (shm_open)"); exit(EXIT_FAILURE); } } else { if((fd=shm_open(id.key,O_RDWR,0666))<0) { perror("Getting existing region (shm_open)"); exit(EXIT_FAILURE); } } cout << "fd is " << fd << endl; base=static_cast<char*>(mmap(NULL,sz,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0)); if (base == reinterpret_cast<char*>(-1)) { perror("Attaching region (mmap)"); if(close(fd)<0) perror("Warning: Closing temporary file descriptor from shm_open"); if(shm_unlink(id.key)<0) perror("Warning: Shared memory unlink (shm_unlink)"); exit(EXIT_FAILURE); } if(close(fd)<0) { perror("Warning: Closing temporary file descriptor from shm_open"); }

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Re: Get socket creator (ie: PID & UID)
by Peter Lovell 20 Feb '05

20 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Regards.....Peter On Feb 20, 2005, at 12:04 PM, Vincent Pottier wrote: _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… The whole NKE interface changes with Tiger, and tcplogger will be little if any help there. Have a look at the headers and you may find a function which returns the items you want, rather than returning a pointer-to-struct. My previous comments and suggestions are all related to Jaguar and Panther. Thanks for this quick response, but it don't work better, I always get the dereferencing error. More, the current_proc() isn't in the <sys/proc.h> header. I'm running Tiger maybe here is the probleme, maybe next seed will solve my probleme :¬) Thanks a lot, Vincent This email sent to site_archiver(a)lists.apple.com

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Re: Get socket creator (ie: PID & UID)
by Vincent Pottier 20 Feb '05

20 Feb '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com You'll find the definition of struct proc in <sys/proc.h> You code for pid will be something like the_pid = current_proc()->p_pid; On Feb 20, 2005, at 7:38 AM, Vincent Pottier wrote: On 19 févr. 05, at 18:38, Peter Lovell wrote: On Feb 19, 2005, at 12:15 PM, Vincent Pottier wrote: Hi folks, Does someone can explain me how to use it? Thanks in advance, Hi Vincent, the definition is in <sys/vm.h> (in Kernel.framework) ... struct proc *current_proc(void); _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… Thanks for this quick response, but it don't work better, I always get the dereferencing error. More, the current_proc() isn't in the <sys/proc.h> header. I'm running Tiger maybe here is the probleme, maybe next seed will solve my probleme :¬) Thanks a lot, Vincent On 20 févr. 05, at 16:24, Peter Lovell wrote: Thanks a lot Peter, it work just fine, but I can't find the struct architecture, I've search through the web and in the Header file, but can't find the struct references, I've try with p_pid for the PID (and other few things) , but I always get an error. Can someone tell me where to find this struct references (or find documentation about current_proc)? Thanks in advance, Vincent I've the tcplogger sample code and I would like to get the socket creator PID and UID. After a few search, It looks that I can get it via current_proc() called on socreate time. But this feature is disable in the sample I have and I get an error when using it. (warning: implicit declaration of function 'current_proc'). I've already try to #include some object but can't make it work. Vincent The struct is subject to change of course, but if you're working with tcplogger then you already know that. Regards.....Peter This email sent to site_archiver(a)lists.apple.com

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