[Bug 281131] Potential DMA (DragonflyBSD Mail Agent) Bug

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=281131

--- Comment #3 from Slawomir Wojciech Wojtczak <vermaden@interia.pl> ---
(In reply to Ed Maste from comment #1)

More explanations:

# Mail becomes invisible in mail (/usr/bin/mail) application.
# That's what the Bug Report's example shows.
#
# Precondition to make the phenomenon most easily visible:
# 
# In case the ~/mbox is empty:
# Problem starts to be visible only after the second and following 
# reception of new mail. 


Every time you open "mail" on the shell command line after new 
mail has arrived in the user's system mailbox, then 
this list of new mail in the system mail box is shown, and 
the single messages can be read correctly. 

The phenomenon becomes 
visible only after that: 

After having read all new messages for the first time, 
the user quits the application by pressing 'q'. 
This moves the new messages from 
 the account's system mailbox /var/mail/<account>
 (it was put there by 'dma' local message delivery)
into 
 the users ~/mbox file.
 (this is done by '/usr/bin/mail')

Still, everything looks fine. 

# 
# Hint: ~/mbox should end with and empty separator line (0xA0xA)
# after the last message
# (this prepares for concatenation of new messages incoming later,
# in the next '/usr/bin/mail'-invocation.)
# but it doesn't add a final empty line by itself.
# 'mail' just moves messages previously prepared by
'dma'.
# 

Now, we get new mail, let's say 5 minutes later.
We open '/usr/bin/mail'. It shows the new-mail list from 
/var/mail/<account>, we read them, then we leave with 'q'

Like always, leaving via 'q' moves the mail we have just read 
from: /var/mail/<account>
into: ~/mbox

Now, we want to look at our saved mail once again.
Via "/usr/bin/mail -f".

There is at least one message missing in the list of header lines 
shown within '/usr/bin/mail'.

Just repeat the example, given in the first report. 
Compare the number of messages in ~/mbox against 
 the number of messages shown via "/usr/bin/mail -f". 

###

This is easily repeatable out of the box with a new installation of 
14.1-RELEASE-p4 into any jail (VNET jail, vlan-jail, doesn't matter.)

###

Everything is caused by dma delivery into /var/mail/<account>. 

'dma' doesn't add a final empty line after the last new
message in 
system mail boxes.

This causes concatenation problems when the last message is moved into 
another mailbox, or when whole mailboxes are concatenated. 

###

Again: Repeat the example, and count the number of mails.

 You have to read and save new mail ==> at least twice <== 
 to see it. You'll see it by using "/usr/bin/mail -f",
afterwards.

Greetings.

-- 
You are receiving this mail because:
You are the assignee for the bug.