savecore: Create core.txt.last symlink

[ricardobranco777]

When saving a coredump, savecore(8) maintains .last symlinks for info and vmcore artifacts, but not for the crashinfo text report. Create it to point at the current core.txt.<bounds> file.

This makes /var/crash/core.txt.last track the same dump as info.last and vmcore.last.

Now I have core.txt.last:

$ ls -l /var/crash/
total 2689423
-rw-r--r--  1 root wheel          2 May  2 19:11 bounds
-rw-r--r--  1 root wheel        443 Apr 18 11:27 core.txt.0
-rw-r--r--  1 root wheel        443 Apr 18 11:37 core.txt.1
-rw-r--r--  1 root wheel     146891 Apr 18 11:43 core.txt.2
lrwxr-xr-x  1 root wheel         10 May  2 19:11 core.txt.last -> core.txt.2
-rw-------  1 root wheel        474 Apr 18 11:27 info.0
-rw-------  1 root wheel        474 Apr 18 11:37 info.1
-rw-------  1 root wheel        474 Apr 18 11:43 info.2
lrwxr-xr-x  1 root wheel          6 May  2 19:11 info.last -> info.2
-rw-r--r--  1 root wheel          5 Aug  8  2025 minfree
-rw-------  1 root wheel  854790144 Apr 18 11:27 vmcore.0
-rw-------  1 root wheel  854290432 Apr 18 11:37 vmcore.1
-rw-------  1 root wheel  853876736 Apr 18 11:43 vmcore.2
lrwxr-xr-x  1 root wheel          8 May  2 19:11 vmcore.last -> vmcore.2

[mhorne]

I think the idea is great.

However this is not the right place to implement it. The core.txt files are generated by the /usr/sbin/crashinfo shell script, not by savecore itself.

So the symlink should be generated there.

[ricardobranco777]

I think the idea is great.

However this is not the right place to implement it. The core.txt files are generated by the /usr/sbin/crashinfo shell script, not by savecore itself.

So the symlink should be generated there.

I took a look at crashinfo and it doesn't generate any symlinks at all. All the symlinks are being generated by savecore.

[mhorne]

I think the idea is great.
However this is not the right place to implement it. The core.txt files are generated by the /usr/sbin/crashinfo shell script, not by savecore itself.
So the symlink should be generated there.

I took a look at crashinfo and it doesn't generate any symlinks at all. All the symlinks are being generated by savecore.

That's correct. But savecore creates symlinks to files that it owns/generates. savecore does not know about core.txt.N.

Here is a quick demonstration of the inconsistency (your change is applied):

# mkdir /tmp/newdir
# savecore -L /tmp/newdir
savecore 20213 - - livedump
savecore 20213 - - writing core to /tmp/newdir/livecore.0
# ls -l /tmp/newdir
total 1332821
-rw-r--r--  1 root wheel          2 May 11 11:19 bounds
lrwxr-xr-x  1 root wheel         10 May 11 11:19 core.txt.last -> core.txt.0
-rw-------  1 root wheel        493 May 11 11:19 info.0
lrwxr-xr-x  1 root wheel          6 May 11 11:19 info.last -> info.0
-rw-------  1 root wheel 4357517312 May 11 11:19 livecore.0
lrwxr-xr-x  1 root wheel         10 May 11 11:19 livecore.last -> livecore.0

It has created a symlink to core.txt.0, but this file does not exist. Not unless I run crashdump. By default, this is done automatically by rc(8), but is a distinct operation.

So, it belongs in crashdump.sh, and should be as simple as:

LINK=$CRASHDIR/core.txt.last
ln -s $FILE $LINK

[ricardobranco777]

So, it belongs in crashdump.sh, and should be as simple as:

LINK=$CRASHDIR/core.txt.last
ln -s $FILE $LINK

You're right. PTAL #2199