Busybox syslogd truncates messages at ~250 characters

As the title says: When you log messages with syslogd they are cut off after about 250 chars.

To verify try this:

# syslogd
# logger "This manual page documents the GNU version of find. GNU find searches the directory tree rooted at each given file name by evaluating the given expression from left to right, according to the rules of precedence (see section OPERATORS), until the outcome is known (the left hand side is false for and operations, true for or), at which point find moves on to the next file name."
# cat /var/log/messages
Oct 18 09:42:20 syslogd started: BusyBox v1.26.2
Oct 18 10:24:31 91ccfe953917 user.notice root: This manual page documents the GNU version of find. GNU find searches the directory tree rooted at each given file name by evaluating the given expression from left to right, according to the rules of precedence (see section OPER

There’s a similar bug report over at Ubuntu’s launchpad which seems to indicate that this is due to a compile time config variable CONFIG_FEATURE_SYSLOGD_READ_BUFFER_SIZE which defaults to 256. They fixed it by increasing it to 512. Preferrably it should be set even higher, e.g. 1024 to be on the safe side.

(from redmine: issue id 8019, created on 2017-10-18)