- launchd-dev - lists.macosforge.org

Launch on demand from kernel extension?
by Colin 25 Jun '08

25 Jun '08

Hello, I have an OS X kernel extension that has settings that need to be saved and restored (the settings are not per-user). Since a kernel extension cannot read/write a preference file, I have a helper daemon that interfaces with my kext and handles the reading/writing of the preference file. I have recently converted over from using StartupItems to using launchd to launch my helper daemon at startup. Is it possible, using launchd, to have my kernel extension launch the helper daemon on demand? If so, what is the best way to implement this? I need to support OS X 10.4.11 and above. cheers, colin

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Agent terminating & Fast User Switching
by Peter Alshuth 24 Jun '08

24 Jun '08

Hi all, I have an agent running for each user session that gets launched when the user logs in and will be terminated on a logout. In order to have the background agent running even if the user quits it I use the key to KeepAlive (I check the reason for the quit event and return 0 or 1). Everything works fine when only one user is logged in and out. But when I log out from a fast user switching it will be restarted: He agent fist received the quit event and will terminate by calling exit(1) at the very end. Unfortunately, it will be relaunched during the user logout and the process will immediately receive SIGTERM signal that I also response to. <plist version="1.0"> <dict> <key>KeepAlive</key> <dict> <key>SuccessfulExit</key> <true/> </dict> <key>Label</key> <string>com.mycompany.myAgent</string> <key>OnDemand</key> <false/> <key>ProgramArguments</key> <array> <string>/usr/local/MyStuff/MyAgent.app/Contents/MacOS/ MyAgent</string> </array> <key>RunAtLoad</key> <true/> </dict> </plist> Is there anything I am missing or doing wrong? Thanks for any help, Peter

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launchd and watchpath
by Don Montalvo 08 Jun '08

08 Jun '08

We would like to set up a folder on our Macs that forces incoming files/folders to inherit permissions. Instead of ADL's, we'd like to use launchd (and watchpath). I'm not familiar with launchd, so I think this would be a good way to get my feet wet. The shared folder would be: /Users/Shared/WORK Each user would have an alias to it on their Desktop (created via logout hook): ~/Desktop/WORK How can I set up launchd to watch this folder and ensure the contents are always set to 777? I don't have experience with launchd. I toyed with it in early Tiger days but there were issues with user launchd so I gave it up and stuck with cron. I understand launchd works as advertised on Leopard. Hoping it can help with this little project. :) Thanks, Don

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Re: [launchd-dev] Wiki
by Ian Eiloart 06 Jun '08

06 Jun '08

--On 5 June 2008 10:49:56 -0700 Dave Zarzycki <zarzycki(a)apple.com> wrote: > Ian, > > I don't know about wiki access, but if you propose some changes for the > 'man' page, I'd consider incorporating them. > > davez > Hmm, OK. So, would you consider adding this to the man page: Define kern.hostname in /etc/sysctl.conf if you need a process to load at boot time. Is there any official documentation other than the man page? I'd like to document much more than is appropriate for a man page - more examples, more use cases, etc. -- Ian Eiloart IT Services, University of Sussex x3148

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Re: [launchd-dev] LimitLoadToHosts doesn't work with RunAtLoad
by Ian Eiloart 06 Jun '08

06 Jun '08

--On 5 June 2008 10:49:14 -0700 Dave Zarzycki <zarzycki(a)apple.com> wrote: > > Ian, > > Does adding "kern.hostname=snow.uscs.susx.ac.uk" to /etc/sysctl.conf fix > this behavior? > > davez Yes, it does. Thanks! I still have to maintain a file for each host, but I guess I've achieved what I wanted - a common set of files for automatic configuration based on host identification. -- Ian Eiloart IT Services, University of Sussex x3148

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Wiki
by Ian Eiloart 05 Jun '08

05 Jun '08

Hi, Is it possible to get write access to the wiki? I'd like to put some documentation up there - mainly to expand on what's in the launchd.plist man file. -- Ian Eiloart IT Services, University of Sussex x3148

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LimitLoadToHosts doesn't work with RunAtLoad
by Ian Eiloart 05 Jun '08

05 Jun '08

Hi, I have a cluster of mail servers, using Wackamole to ensure IP failover. I start wackamole at startup, since it requires to be available all the time. Actually, I require NetworkState to be true. Each server has a different set of preferred IP addresses, so each requires a different wackamole configuration file. I'm maintaining the software using RADMIND, and the simplest thing to do is place all the files on all the servers. I had hoped that launchd's LimitLoadToHosts key would help me out here, so I created a plist file for each server. The trouble is that adding the following key to the plist seems to stop the service loading at startup, although it lets me load the service from the command line. It works as expected on the other hosts, preventing loading at any time. <key>LimitLoadToHosts</key> <array> <string>snow.uscs.susx.ac.uk</string> </array> Is this a bug in launchd? Does it work with, for example, on demand services? My full (working) plist is here: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>EnvironmentVariables</key> <dict> <key>DYLD_LIBRARY_PATH</key> <string>/opt/local/lib</string> </dict> <key>KeepAlive</key> <dict> <key>NetworkState</key> <true/> </dict> <key>Label</key> <string>org.wackamole.snow</string> <key>ProgramArguments</key> <array> <string>/opt/local/sbin/wackamole</string> <string>-c</string> <string>/opt/local/etc/wackamole.snow.conf</string> <string>-d</string> </array> <key>RunAtLoad</key> <true/> </dict> </plist> -- Ian Eiloart IT Services, University of Sussex x3148

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Check-in failed?
by Vyacheslav Karamov 02 Jun '08

02 Jun '08

Hi All! I'm writing my first launchd-enabled daemon, It works in Tiger, but not in Leopard. It writes "Check-in failed:" into syslog end exits. Here is my code: int main (int argc, char * const argv[]) { signal(SIGTERM, SigtermHandler); signal(SIGINT, SigtermHandler); /* * Create a new ASL log * */ g_asl = asl_open("AudioServer", "Daemon", ASL_OPT_STDERR); log_msg = asl_new(ASL_TYPE_MSG); asl_set(log_msg, ASL_KEY_SENDER, "AudioServer"); asl_set_filter(g_asl, ASL_FILTER_MASK_UPTO(ASL_LEVEL_INFO)); /* * Register ourselves with launchd. * */ launch_data_t checkin_request = launch_data_new_string(LAUNCH_KEY_CHECKIN); if ( checkin_request == NULL ) { asl_log(g_asl, log_msg, ASL_LEVEL_ERR, "launch_data_new_string(\"" LAUNCH_KEY_CHECKIN "\") Unable to create string."); return EXIT_FAILURE; } launch_data_t checkin_response = launch_msg(checkin_request); if ( checkin_response == NULL ) { asl_log(g_asl, log_msg, ASL_LEVEL_ERR, "launch_msg(\"" LAUNCH_KEY_CHECKIN "\") IPC failure: %m"); return EXIT_FAILURE; } if (LAUNCH_DATA_ERRNO == launch_data_get_type(checkin_response)) { errno = launch_data_get_errno(checkin_response); asl_log(g_asl, log_msg, ASL_LEVEL_ERR, "Check-in failed: %m"); return EXIT_FAILURE; } .... } $ cat /Library/LaunchDaemons/com.circle.AudioServer.Debug.plist: <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE plist/ (View Source for full doctype...)/> - <#> <plist version="*1.0*"> - <#> <dict> <key>Label</key> <string>com.circle.AudioServer</string> <key>OnDemand</key> <false /> <key>ProgramArguments</key> - <#> <array> <string>/Users/slava/Projects/AudioServer/build/Debug/AudioServer</string> </array> <key>RunAtLoad</key> <true /> <key>ServiceIPC</key> <true /> </dict> </plist> Both binary and property list have root:wheel 755 permissions

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Listening socket and fast user switching
by Dave Dribin 22 May '08

22 May '08

Hello, I'm writing a launchd agent that opens a TCP listening socket. Ideally, I'd like launchd to open and listen to the socket via SockServiceName so my agent only gets launched as-needed. The problem is I'd like to listen to the same port (e.g. 12345), no matter which user is logged in. This is fine when there's only one user logged in, but as soon as fast user switching comes into play, the socket gets an "address already in use" when the second user logs in. This is to be expected, I suppose. But is there any way to have launchd only listen to the socket when the user is the "active" user, and have it *not* listen when the user gets switched out, due to fast user switching? At first glance the LimitLoadToSessionType looked promising, but it doesn't look like any of those will do that. The solution I'm currently entertaining uses launchd to always launch my agent, and have my agent do the socket listening. I can then use the user switch notification to close down the listening port when the session is deactivated and open it when activated. Thanks, -Dave

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QueueDirectories problem
by Michal Taurich 08 May '08

08 May '08

Hello all, I have very strange launchd problem. I wrote a small script to watch defined folder and if anything is added to this folder, it copy the file via SCP to different machine and than move the file to another folder. The script looks like following: #!/bin/bash in=/in remote="user@xxx.xxx.xxx.xx:/path" out=/out OLDIFS=$IFS IFS="$(echo -e \"\\n\")" for i in $(find $in -type f) do IFS=$OLDIFS scp "${i}" "${remote}" IFS=$OLDIFS if [ $? = 0 ]; then mv "${i}" "${out}" fi; done IFS=$OLDIFS exit 0 I have also launchd .plist for it like follows: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <string>scp_upload</string> <key>ProgramArguments</key> <array> <string>/script</string> </array> <key>QueueDirectories</key> <array> <string>/in</string> </array> <key>RunAtLoad</key> <true/> </dict> </plist> It works perfectly locally. Unfortunately, when I run it on remote host and connect to shared drive via AFP and try to copy file from my computer to "watched folder" I got errors like "Unsupported character" or "filename too long" or so. I discovered, the launchd starts immediately when filesytem is changed (The Finder shows 4 kb as file size, but in Terminal it shows 0 kb so I think it is copied just header). Imagine following example: You want to receive some incoming files from internet (e.g. several customers send you images) and you want to move it according filenames (filenames are only numbers). So files starts with 1xxxx will be moved to folder 10000-19999. And now comes the tricky situation. Because launchd works like it works, when customer starts uploading the file, there is made a file system record for that file. But because launchd is set as "watching for folder changes" it tries to move the file, even the file is not completed (imagine e.g. 20 MB print quality photos). So launchd fails and write in console log "threat" like "9 times I will fail and I will disable myself". So it is just a question of time when launchd will disable itself. So my question is how to avoid this behaviour. I tried to add an condition in my script based on following: lsof | grep -c "${in}/${i}" if [ $? = 0 ]; then exit 0; fi Basically it checks in list of open files, if the file is opened, if yes, than exit0, otherwise continue. But it also sometimes works and sometimes not (better say, some files are moved and some not and I can wait hours and the files sit on the same place even launchd is running). So I would like to ask someone if have some experience with this problem and can recommend me some workarround or some approved and tested way, how to avoid move/copy/rename or whatever incomplete files. Thanks in advance. Michal

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