https://gitlab.synchro.net/main/sbbs/-/commit/01b9084b2a55c2486a512760
Added Files:
src/smblib/tests/smbupdatetest.c
Modified Files:
src/sbbs3/writemsg.cpp src/smblib/smbfile.c smblib.h src/smblib/tests/GNUmakefile
Log Message:
Edit only a message's body, and write its new text before freeing the old

editmsg() freed a message's data blocks before allocating and writing
the replacement, and wrote the header last. A failure in between (an
allocation or write error, or a crash) left the header naming blocks that
were already free, which the next message could be given and overwrite.

It also put the body and tail (the signature, or an imported message's
tear and origin lines) in the editor together and stored the result as a
single body field, so after an edit the tail was no longer kept apart:
the terminal server word-wrapped the signature with the body, and
JavaScript readers found it in the body instead of the tail.

editmsg() now edits only the body and keeps the tail as it is, and stores
the text with the new smb_updatemsgtxt(), which writes the new data
blocks, then the header and index, and only then frees the old blocks.
A failure part-way leaks blocks (which chksmb reports and fixsmb
reclaims) rather than leaving the message pointing at freed ones.

smb_updatemsgtxt() is the former body of smb_updatefile(), from
3a687044d3 (item-11-focal, 2026-09-21), which already replaced a file
record's text this way; smb_updatefile() now calls it.

Add smbupdatetest to src/smblib/tests.

Fixes #1252
Fixes #1270

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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