November 2011 - Darwin-dev - lists.apple.com

Re: Launchd, AbandonProcessGroup, system() vs fork/exec
by Tilghman Lesher 02 Nov '11

02 Nov '11

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=meg.abyt.es; s=google; h=mime-version:x-originating-ip:in-reply-to:references:date :message-id:subject:from:to:content-type; bh=FDSVGTSEBxVLbzJOIdHwiOtiEoBlQhBOMQOlk1bmS1o=; b=f5gqrEwfsOjAx/4C4qCxYOWCaHFeheilGB6jQaW63B2bWAyMI4AFBpjLBeMehgUp8m 0ZsYaUw9udaqf7NpsHIAV7qJ221SDKvryDEyc/n9oqoqVE47klwcTqzqqAm5dtoQRd1e UsMHnnPKe6a/vl2fX2QYPQ6cdW7Eqlz+fOmkk= On Wed, Nov 2, 2011 at 1:57 PM, Jason Coco <jason(a)9mmedia.com> wrote: > I believe it's designed to allow short-lived processes to complete whatever > service they're providing if the parent dies unexpectedly, not for when the > parent exits and basically says "okay, I'm all done," like in your case. An > example might be an http daemon that uses processes to service individual > requests. If the daemon process dies, the child processes are given a chance > to complete their service and exit before being killed and reaped by > launchd. If the OP is wanting to do things in parallel, however, he might try to call waitpid() in the parent before exiting. Another possible solution might be to sleep(1) before exiting in the parent. It might be enough to trick launchd into thinking that the process wasn't simply doing the "moral equivalent" of daemon(3) (see the launchd.plist manpage). And finally, a third solution might be to call setsid() in the child prior to the execl(). This will ensure the child has a different process group ID, thus avoiding the issue with launchd killing processes with the same process group ID. One caveat: ensure the parent sleep()s before exit()ing, or the exit of the parent may occur before the child has a chance to setsid(). _______________________________________________ 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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Re: Launchd, AbandonProcessGroup, system() vs fork/exec
by Jason Coco 02 Nov '11

02 Nov '11

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Re: Launchd, AbandonProcessGroup, system() vs fork/exec
by Todd Heberlein 02 Nov '11

02 Nov '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com I guess my confusion is the purpose/use of <key>AbandonProcessGroup</key> <true/> Isn't this supposed to address this issue? That is, let the child processes live on after the parent process has exited? Todd _______________________________________________ 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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Re: Launchd, AbandonProcessGroup, system() vs fork/exec
by Stéphane Glondu 02 Nov '11

02 Nov '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.23) Gecko/20111010 Icedove/3.1.15 On 11/02/2011 05:08 PM, Jason Coco wrote: > I'm assuming that your main program exits relatively quickly after calling system(3) or execl(3). You simply *can't* do this when using launchd. The reason it appears to work in the first case is that system(3) actually blocks until the new process exits. This keeps your process alive during the entire life of the child, which is what launchd expects and wants, making it appear to work correctly (although none of your subsequent instructions get processed until after the system(3) call returns, so you're not actually doing any work in parallel). With exec(3), your process probably returns before the child, which launchd isn't going to be very happy with. Depending on what you're doing, it may just be best to keep your main process around until all its children are finished, and then exit cleanly after reaping them. Or maybe you can just avoid forking and waiting for the child, and call directly exec() if the caller really has nothing to do after the callee returns... Cheers, -- Stéphane _______________________________________________ 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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Re: Launchd, AbandonProcessGroup, system() vs fork/exec
by Jason Coco 02 Nov '11

02 Nov '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.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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Launchd, AbandonProcessGroup, system() vs fork/exec
by Todd Heberlein 01 Nov '11

01 Nov '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Don't know if Darwin-dev is the right place for this question... if not, please point me in the right direction. I have a UNIX program started by launchd when a file system is mounted. In this program I create a second process to carry out some additional task. In my .plist file I have AbandonProcessGroup set to <true/>. Starting the second program this way works fine: system(execution_path.c_str()); But starting the program this way does *not*: child_pid = fork(); if (child_pid == 0) { execl(execution_path.c_str(), execution_path.c_str()); ... } Both approaches work when launching the program from the command line. Why does the AbandonProcessGroup not work in the second version? Todd _______________________________________________ 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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Re: Darwin Noob Question
by Tilghman Lesher 01 Nov '11

01 Nov '11

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=meg.abyt.es; s=google; h=mime-version:x-originating-ip:in-reply-to:references:date :message-id:subject:from:to:content-type; bh=Hz1qDCD20KK3FZ3SFpYELmvS2ixCMEPuEQWZoJVJvlw=; b=dQ6JNX+PdrWZF+XcirSCwg6KgBFBJYU0KJ/IOruNN1XjruVIB6qGn9RwjqqPW0ZfN/ SHmZanGfL3tDiCqMpOpDg9jIO/+dKchX0+wHIBET9AIfY3bPskPQXXQn3ImKR7v+AM+N N8KgnHGe+zdKoViok+n4bUHa1/mGxi1S7UXTw= On Tue, Nov 1, 2011 at 2:09 AM, chriskxu <chriskxu(a)me.com> wrote: > Hi there, > I'm new to darwin development, and I have a newbie question, are there some > apis that I can call to get general process and thread information(pid, > memory usage, cpu, etc...) in user space. Normally on linux, I would use > /proc, but as I understood there are no such things on OSX. Can someone help > me with this? man 3 sysctl This is the way that top(1) does it: http://opensource.apple.com/source/top/top-73/libtop.c -Tilghman _______________________________________________ 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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Darwin Noob Question
by chriskxu 01 Nov '11

01 Nov '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.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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