Bug 236117 - /usr/sbin/daemon should support stdin,stdout,stderr redirect to files other than /dev/null
Summary: /usr/sbin/daemon should support stdin,stdout,stderr redirect to files other t...
Status: Open
Alias: None
Product: Base System
Classification: Unclassified
Component: bin (show other bugs)
Version: 11.2-STABLE
Hardware: Any Any
: --- Affects Some People
Assignee: freebsd-bugs (Nobody)
URL:
Keywords: feature
Depends on:
Blocks:
 
Reported: 2019-03-01 01:06 UTC by TAO ZHOU
Modified: 2024-06-15 10:13 UTC (History)
6 users (show)

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Description TAO ZHOU 2019-03-01 01:06:59 UTC
The daemon command has an option `-f`, which, according to the man page, redirects stding,stdout,stderr to /dev/null.

This is fine. But if I cannot redirect stdin, stdout, stderr to different files respectively.

There is a `-o` option, 

```
  -o output_file
             Append output from the daemonized process to output_file.  If the
             file does not exist, it is created with permissions 0600.
```

The problem I am having now is that daemon command was used in some freebsd rc.d scripts without the `-f` option. When I try to restart those services through python subprocess.Popen, it would hang indefinitely. 

The problem can be easily reproduced by 

```
python3 -c 'import subprocess; subprocess.Popen(["/usr/sbin/service", "mytestservice", "onerestart"], stderr=subprocess.PIPE).communicate()'
```

I can add the `-f` option to fix the problem, but `-f` will override the `-o` option, and I end up with no log at all.


I think it would be nice if the daemon command can support redirecting stdin, stdout, stderr separately.
Comment 1 Ihor Antonov 2023-03-06 04:12:30 UTC
I am working on daemon improvements and this feature is planned to be added once transition to kqueue is finished.
Comment 2 Ihor Antonov 2023-04-15 00:45:04 UTC
zhoutao@laocius.org:

You could send logs to syslog, if that works for you.
Check these daemon options:

--syslog       Send output to syslog 
--output-mask  What to send to syslog/file
	       1=stdout, 2=stderr, 3=both


I know this is not ideal. I am thinking about the way to add the feature you request without breaking the current interface and without making it inconsistent/incoherent..
Comment 3 Tatsuki Makino 2024-06-15 10:13:29 UTC
Although it's also weird that I'm still using 12.4-STABLE... :)
I replaced /usr/sbin/daemon with one built using the 10.4-STABLE source code.
This is because the behavior of standard output and standard error output has changed.

I used to use it as follows, but the current version, which specializes in log output, changes in content.
daemon -p /tmp/daemon.pid cat /dev/somedevice > /tmp/output.dat

I had to update FreeBSD to 13 or 14, but I looked for a workaround to avoid using daemon of version 10, and I got the following.
daemon -p /tmp/daemon.pid -m 0 -o /dev/null cat /dev/somedevice > /tmp/output.dat

Setting -m to 0 is not in usage, but it prevents the two output descriptors of the child process from switching to the log pipe.
Using the -o or -S options suppresses the output of the log to standard output.

It seems that stdin, stdout, and stderr will now be the same as when daemon is started.
I finally got to it today :)