[pca] README check / switch for skipping patches that must be applied in single-user mode

[Martin Paul]

Hi Dave,

> Given that the --safe and --noreboot switches are in PCA, has Martin &
> Co. considered adding a check in the README to skip patches that must be
> applied in single mode, or does the --noreboot switch cover that
> already?  My impression from talking with Sun is that "reboot-required"
> does not necessarily equate to "apply in safe mode".

First, don't confuse the "--safe" option with applying a patch in single 
user mode. The safe mode checks for files which you might have modified 
locally and which might get overwritten by a patch. The recommendation 
to apply a patch in single user mode is to protect you from strange 
effects when a patch might overwrite open files (like shared libraries), 
possibly modifying APIs etc.

As for the patch properties: Back when I implemented the "noreboot" 
option, I looked at and analyzed the properties for most if not all 
available patches, and I found only a handful of patches which had 
"singleuser" listed but not "reboot*/reconfig*"; some of them were even 
plain wrong: I see that e.g. 123520-01 for basename/dirname still reads 
"Install in Single User Mode", which I don't see any reason for.

That's why I decided to ignore the "singleuser" property for the 
"--noreboot" option. Even if the situation would have changed since 
then, the only reason for me to look at this again would be Sun's 
decision to include the patch properties in the patchdiag.xref file 
(which I don't expect), because then "--noreboot" could be used without 
having to download all patches in advance.

hth,

Martin.