April 2009 - Darwin-dev - lists.apple.com

Re: Raw backup and restore of disks in Mac OS X
by Jean-Daniel Dupas 23 Apr '09

23 Apr '09

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Le 23 avr. 09 à 08:30, rohan a a écrit : However, when I do : # ls -l /dev Why reinventing the wheel ? man hdiutil man asr _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Hello, I need to write code to do a raw backup/restore of a disk in Mac OS X. When I do a: # diskutil list It shows me the drives as disk0s1, disk0s2, disk0s3 etc. It shows me disk0s1, disk0s2, disk0s3 (block device)etc. But along with these it also shows rdisk0s1, rdisk0s2, rdisk0s3(character device) For a raw backup, what should I be using block device or character device? With Linux, I use the block devices and not the character devices. This email sent to site_archiver(a)lists.apple.com

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Determining file-system ACL support
by rohan a 23 Apr '09

23 Apr '09

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Raw backup and restore of disks in Mac OS X
by rohan a 23 Apr '09

23 Apr '09

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Re: Macho file format
by Jean-Daniel Dupas 22 Apr '09

22 Apr '09

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Le 22 avr. 09 à 19:04, Arnab Ganguly a écrit : To read mach-o file, there is otool: http://www.opensource.apple.com/darwinsource/DevToolsOct2008/cctools-698.1/… And this format is documented: http://developer.apple.com/documentation/DeveloperTools/Conceptual/MachORun… _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Hi Al, Any tutorial or sample program available for reading Macho file or DWARF format ? Thanks in advance Arnab This email sent to site_archiver(a)lists.apple.com

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Re: ACL API ( acl_copy_ext) and ( acl_copy_int) not available for application!!!
by Terry Lambert 22 Apr '09

22 Apr '09

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Hi, Thanks for the reply.. -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On Apr 22, 2009, at 4:03 AM, Singh, Gangadhar S (BIO) wrote: In Linux, we were using these APIs for processing the data between user managed space and kernel space. Similar requirement has come up for Mac OS X. So basically you are using it as a communications channel between user space and the kernel. Bad idea. The internal representation in the kernel is as a filesec_t, and there are APIs for dealing with that *in the kernel*. In user space, you are expected to use the user space interfaces for dealing with getting and setting ACLs. There is no opportunity for using this interface as a covert channel to pass data in and out of, for example, a third party FS. If that's what you want to do, you will need to look elsewhere (such as using fcntl(0 to access through VNOP_IOCTL into the filesystem). You are basically not allowed to look into the opaque type information in user space (for one thing, the filesec_t is an opaque pointer type; for another, we do not guarantee byte order, endienness, or structure packing between platforms or between kernel and user space; you basically get whatever the native volume format is, and for that, you get whatever the native endienness and packing was on the system it was created on. So User Application cannot use this APIs since it is not available in the man pages right? Incorrect. Whether or not there is a man page for something, an exported API is an exported API. However, not all exported API is useful, and some exported API is not documented, either to deprecate it or to strongly discourage its use. Anything you did with the internally formatted information would basically not be portable between releases or software updates, since you are supposed to treat the contents as opaque. If you google the FreeBSD implementation of POSIX 1003.1e, which is what the OpenBSD, MacOS X, SGI IRIX, Tru64 UNIX (from your own company), Linux, and other implementations are based upon, you will see that out of the > 100 first results you get back, absolutely none of them are code examples trying to use them from user space. There is a reason for that. It's because of the opaque parts not having defined accessor/mutator functions usable from user space. Those are intentionally not defined by most vendors (including Apple) because there is a problem with integer UID vs. ACL UUID coherency, if you let user space jam any UUID they want into things. Specifically, no one has solved the cardinality issue where multiple UUIDs in multiple directory services end up mapping to the same 32 bit inter value of a uid_t or gid_t in a normal UNIX credential. This happens because the people who came up with UUIDs in the first place ignored a lot of inconvenient problems, such as existing file systems and backup archives. Effectively, that means that you can't take an integer value and map it back to a single UUID when you are trying to put an ACL on something, you basically have to guess, or you have to set a priority ordering on your directory service. If you use the read/modify/write paradigm, for example, and explicitly check for the attribute information after the read before the modify/ write, the interfaces could possibly be useful for backup/restore. But if you were trying to create one from scratch and then use acl_copy_int() to intern it for the kernel to see, your code is going to be broken. It will also be broken if you store and retrieve the internal data format, and also if you communicate the internal data format between computers in an effort to replicate contents. The read step is necessary to ensure that the opaque parts of the data for which there is no useful user space portion (or API for modification from user space) is filled out correctly by the kernel. Which are the appropriate APIs that can be used for exchanging the ACL data between kernel and user space. chmodx_np, fchmodx_np, openx_np, accessx_np, getattrlist, setattrlist, and so on are the appropriate APIs for use in user space ACL manipulation. In kernel space, your file system is supposed to implement the VNOPs that correspond to ACL operations. See our published source code for various file systems for examples. This email sent to site_archiver(a)lists.apple.com

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Macho file format
by Arnab Ganguly 22 Apr '09

22 Apr '09

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Re: Detecting moved files
by Terry Lambert 22 Apr '09

22 Apr '09

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On Apr 22, 2009, at 5:01 AM, Rohan Kulkarni <rohan.ak1(a)gmail.com> wrote: Hello, I moved a file from one directory to another on the same partition. However, when a do a stat on the file before and after the "move" the inode change time(ctime) does not get updated. Why is this? Because you haven't changed the file contents. Since you didn't change the contents, the file change time (ctime) is not updated. You are looking at the wrong timestamp field. The mtime may or may not be updated; depending on the internal implementation details of a particular file system, the rename may be treated as a link plus an unlink, in which case the link count goes from N to N+1 and back to N non-atomically, even if the rename is idempotent; since it's not an atomic operation in that case, it counts as two metadata updates. Alternately, one of the pieces of metadata that could be maintained on a per file object basis could be a pointer to its container. If either of these were true, then there would be a metadata time stamp (mtime) update. If what you rename is a directory, then the .. file in the directory is rewritten in the renamed directory to point to the parent. Again, as an implementation detail, if directories are implemented using file content, then the crime will be updated. If they are not, then the mtime will be updated. Since file times updates in POSIX are only mandated for file objects, as a technicality, it may be that only the containing directories rather than the directory which us renamed get updated. In any case, a sufficiently privileged process can set the timestamp fields to whatever it wants (otherwise it would be impossible to implement image backup and restore programs), which would also make structural changes undetectable by naievely examining timestamps. To learn more about the timestamp fields and "shall be marked for update" vs. "shall be updated" events, you should read Go Solo: The Single UNIX Specification. This document is also called POSIX 1003.1-2003, and is available for viewing online at The Open Group web site. If you are attempting to detect rename events for security purposes, you should search for "kauthorama" on <http://developer.apple.com>, and expect that your solution will require you writing a KEXT. This email sent to site_archiver(a)lists.apple.com

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Re: ACL Types supported in Mac OS X
by James Peach 22 Apr '09

22 Apr '09

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=U7H9D4W+SS4LjHtoNPxb8LWQ1El+HLTFIqdlZgfxte8=; b=MU3WrbzYWs+u+fTlSgWRGPPxXv1OFYwBG9s/neyHfOW/n2e7xYT/FpqczW0V7qQjFt Bn5pRG5+R+mDUQEe52Gui9SdDtKVKskary5PB5F63pY6p7JheQWveIpNSqxPoNm10xwm x0hIfg3CArJq4lwqHhaCd62mIwUWEBbJA8gwg= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=B0fuJXmvr1GYIDaR8/T8f3P0ocESeTZFwi/0VxqBVX+ItyEBSWDSG/GkT75wkM/qtW Q/HEoMAzeaaPiuo5R6RelnNHTbWEeQyCOecwAmT0CYQYqguG08jTZJCbmjmDsBhPOMsG M/6VPu541zZuh9eiZyTsuxhV0C6SQ78lHbrOM= 2009/4/22 Singh, Gangadhar S (BIO) <gangadhar.singh(a)hp.com>: > Hi , > > According to man pages of acl_get_fd_np(), it says that it's possible to > retrieval any type of ACL from a file descriptor. > But in the /usr/sys/acl.h, I see most of the ACL types are commented as > not supported, bit confuse here. > > Could anybody clarify what acl type are supported? > > /* 23.2.6 Individual ACL types */ > typedef enum { > ACL_TYPE_EXTENDED = 0x00000100, > /* Posix 1003.1e types - not supported */ > ACL_TYPE_ACCESS = 0x00000000, > ACL_TYPE_DEFAULT = 0x00000001, > /* The following types are defined on FreeBSD/Linux - not supported */ > ACL_TYPE_AFS = 0x00000002, > ACL_TYPE_CODA = 0x00000003, > ACL_TYPE_NTFS = 0x00000004, > ACL_TYPE_NWFS = 0x00000005 > } acl_type_t; ACL_TYPE_EXTENDED is supported -- James Peach | jorgar(a)gmail.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Detecting moved files
by Rohan Kulkarni 22 Apr '09

22 Apr '09

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ACL Types supported in Mac OS X
by Singh, Gangadhar S (BIO) 22 Apr '09

22 Apr '09

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