Message-id: <0KTF005VJVXCFSS9@vms173013.mailsrvcs.net>
Date: Fri, 20 Nov 2009 22:20:00 -0500
To: randomerror AT yahoo DOT com, cygwin AT cygwin DOT com
From: "Pierre A. Humblet" <Pierre DOT Humblet AT ieee DOT org>
Subject: Re: Cron on Windows 7 as a Service Does Not Execute Jobs
In-reply-to: <9E6BBE7F-3D5F-4DC5-B701-367AC5DF9C14@yahoo.com>
References: <9E6BBE7F-3D5F-4DC5-B701-367AC5DF9C14 AT yahoo DOT com>
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At 06:43 PM 11/20/2009, randomerror wrote:
>All,
>
>I can't seem to get cron to execute jobs under Windows 7 (Ultimate.) 
>Here are the things I've done...
>
>----------------------------------------
>Installed cygwin for all users, and fixed some permission problems.
>Configured sshd and it works fine.
>Configured exim (without running it as a service) and it works fine 
>(delivers mail through a smart host).
>
>----------------------------------------
>Configured cron through cron-config running under cyg_server (that 
>was created by sshd,) and it runs but does not execute jobs.
>Cronevents shows that the job commands are running, but in reality 
>they are not:
>
>2009/11/20 17:49:02 [cyg_server] /usr/sbin/cron: PID 4080: (user) 
>CMD (echo test)
>2009/11/20 17:50:01 [cyg_server] /usr/sbin/cron: PID 4028: (user) 
>CMD (echo test)
>2009/11/20 17:53:01 [cyg_server] /usr/sbin/cron: PID 3384: (user) 
>CMD (sleep 30)
>2009/11/20 17:54:01 [cyg_server] /usr/sbin/cron: PID 1404: (user) 
>CMD (sleep 30)
>2009/11/20 18:24:01 [cyg_server] /usr/sbin/cron: PID 3928: (user) 
>CMD (echo test > /tmp/abcd)
>2009/11/20 18:25:01 [cyg_server] /usr/sbin/cron: PID 2004: (user) 
>CMD (echo test > /tmp/abcd)
>
>The sleep job was to test whether I can see the job run with ps; I could not.
>
>----------------------------------------
>So I ran cron from the command line (starting MinTTY as an 
>Administrator) as follows:
>
>/usr/sbin/cron -n -x ext,sch,proc,pars,load,misc,bit
>
>This worked: jobs were being executed and output was e-mailed via exim.
>
>----------------------------------------
>Next, I tried to run cron as SYSTEM but that of course failed, with 
>cron starting and immediately stopping.
>Lastly, I used strace to attach to the running cron service, which 
>works up until the point that the job execution would begin:
>
>$ ps -ef
>      UID     PID    PPID TTY     STIME COMMAND
>cyg_serv    3752       1   ?  13:53:57 /usr/bin/cygrunsrv
>cyg_serv    2172    3752   ?  13:53:57 /usr/sbin/sshd
>cyg_serv    1020       1   ?  17:47:17 /usr/bin/cygrunsrv
>cyg_serv    1144    1020   ?  17:47:17 /usr/sbin/cron
>    janos    3240       1   ?  18:28:21 /usr/bin/mintty
>    janos    1168    3240   0  18:28:22 /usr/bin/bash
>    janos    2192    1168   0  18:29:58 /usr/bin/ps
>
>user AT host ~
>$ strace -f -p 1144
>**********************************************
>Program name: C:\cygwin\usr\sbin\cron.exe (pid 1144, ppid 1020)
>App version:  1005.24, api: 0.156
>DLL version:  1005.25, api: 0.156
>DLL build:    2008-06-12 19:34
>OS version:   Windows NT-6.1
>Heap size:    402653184
>Date/Time:    2009-11-20 18:35:19
>**********************************************
>.
>.
>.
>   183 42989963 [main] cron 3012 build_env: envp 0x61169EB0, envc 28
>    46 42990009 [main] cron 3012 child_info::child_info: subproc_ready 0x198
>  8151 42998160 [main] cron 3012 spawn_guts: 3012 = spawn_guts 
> (/bin/sh, C:\cygwin\bin\sh.exe -c "/bin/echo test")
>    98 42998258 [main] cron 3012! spawn_guts: new process name 
> C:\cygwin\bin\sh.exe
>   135 42998393 [main] cron 3012! _pinfo::dup_proc_pipe: duped 
> wr_proc_pipe 0x4 for pid 3012(2056)
>Windows process 4080 attached
>Windows process 3004 attached
>Windows process 3012 attached
>strace: couldn't attach to subprocess 2056 for debugging, windows error 5
>
>This crashes cron, so it needs to be restarted.
>
>----------------------------------------
>Does anybody have any pointers on what else to check or how else to 
>diagnose why the jobs are not running?
>
>Regards,
>
>John

You have done everything right, AFAICS, and a pretty good debugging job.
I see "user" in the log, is that an actual user name ?

Except for that, as far as cron is concerned, everything looks OK.
Presumably you have seen a successful setuid in the strace.
Cron prints the log line and execs sh, without checking if it 
succeeds, but there
is nothing it can do about that. It's a cygwin issue.
Presumably you are using 1.7
Unfortunately I don't have Windows 7 to reproduce the problem.

Not sure what to suggest. Perhaps running "strace  cron" as a service
would give you more info. That will fill /var/log/cron.log pretty fast :)


Pierre (cron maintainer)


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