[Crash-utility] Re: paging command [was Re: crash CPU bound waiting for user response]
D. Hugh Redelmeier wrote:
| From: Dave Anderson <anderson(a)redhat.com>
| > ==> It does not say in what way the terminal is not fully functional. That
| > seems like a bug.
|
| Sorry, but I have no idea where that WARNING message is coming from,
| i.e., it's not coming from the crash/gdb code base, nor does the
| string "functional" show up in any of the external libraries. There
| is a crash function that prints "WARNING:" before a passed-in message,
| but no instances of it issue that "functional" message. And the
| "(press RETURN)" is most certainly not associated with the crash/gdb
| code base.
|
| So I don't know what the "It" is.
Right.
It seems to be coming from /usr/bin/less.
Based upon running within that emacs/Jove environment I guess?
So I tried to suppress by setting the PAGER environment variable to
/bin/cat. No luck.
The code in main.c:setup_environment ought to use the PAGER
environment variable if it is defined. This would require changing
scroll_command field, probably from an int to a string containing the
command's path. (It is probable that a copy of the string need not be
created since environment variable values are stable.) I would be
willing to propose a patch if you (Dave) would be willing to consider
it.
I prefer not to change the default behaviour based upon the
user's PAGER variable. I'm not sure what you'd want to change
it to, but if you come up with a scheme to do it based upon
a .crashrc entry, or runtime "set" command, or whatever, I'll
certainly consider it. I just don't want to upset everybody
else's applecart.
It turns out that the crash command
set scroll off
does what I need. The crash(8) man page did not even hint at this
capability.
Yeah, the man page is pretty simple-minded. As you can see, I didn't
write it, preferring to keep crash usage documentation self-contained
within the utility itself.
The "help" command shows this:
crash> help
* files mod runq union
alias foreach mount search vm
ascii fuser net set vtop
bt gdb p sig waitq
btop help ps struct whatis
dev irq pte swap wr
dis kmem ptob sym q
eval list ptov sys
exit log rd task
extend mach repeat timer
crash version: 4.0-4.3 gdb version: 6.1
For help on any command above, enter "help <command>".
For help on input options, enter "help input".
For help on output options, enter "help output".
crash>
And "help output" shows this:
crash> help output
By default, crash command output is piped to "/usr/bin/less -E -X" along
with a prompt line. This behavior can be turned off in two ways:
1. During runtime, enter "set scroll off" or the alias "sf".
2. Enter "set scroll off" in a .crashrc file, which can be located either
in the current directory or in your home directory.
To restore the scrolling behavior during runtime, enter "set scroll on"
or the alias: "sn"
...
Dave