Ubuntu Manpage: clamd - an anti-virus daemon

Provided by: clamav-daemon_0.103.12+dfsg-0ubuntu0.20.04.1_amd64

NAME

       clamd - an anti-virus daemon

SYNOPSIS

       clamd [options]

DESCRIPTION

       The  daemon  listens for incoming connections on Unix and/or TCP socket and scans files or
       directories on demand. It reads the configuration from /etc/clamav/clamd.conf

COMMANDS

It's recommended to prefix clamd commands with the letter z (eg. zSCAN) to indicate that
the command will be delimited by a NULL character and that clamd should continue reading
command data until a NULL character is read. The null delimiter assures that the complete
command and its entire argument will be processed as a single command. Alternatively
commands may be prefixed with the letter n (e.g. nSCAN) to use a newline character as the
delimiter. Clamd replies will honour the requested terminator in turn. If clamd doesn't
recognize the command, or the command doesn't follow the requirements specified below, it
will reply with an error message, and close the connection.

Clamd recognizes the following commands:

PING Check the server's state. It should reply with "PONG".

VERSION
Print program and database versions.

RELOAD Reload the virus databases.

SHUTDOWN
Perform a clean exit.

SCAN file/directory
Scan a file or a directory (recursively) with archive support enabled (if not
disabled in clamd.conf). A full path is required.

CONTSCAN file/directory
Scan file or directory (recursively) with archive support enabled and don't stop
the scanning when a virus is found.

MULTISCAN file/directory
Scan file in a standard way or scan directory (recursively) using multiple threads
(to make the scanning faster on SMP machines).

ALLMATCHSCAN file/directory
ALLMATCHSCAN works just like SCAN except that it sets a mode where scanning
continues after finding a match within a file.

INSTREAM
It is mandatory to prefix this command with n or z.

Scan a stream of data. The stream is sent to clamd in chunks, after INSTREAM, on
the same socket on which the command was sent. This avoids the overhead of
establishing new TCP connections and problems with NAT. The format of the chunk is:
'<length><data>' where <length> is the size of the following data in bytes
expressed as a 4 byte unsigned integer in network byte order and <data> is the
actual chunk. Streaming is terminated by sending a zero-length chunk. Note: do not
exceed StreamMaxLength as defined in clamd.conf, otherwise clamd will reply with
INSTREAM size limit exceeded and close the connection.

FILDES It is mandatory to newline terminate this command, or prefix with n or z.

This command only works on UNIX domain sockets. Scan a file descriptor. After
issuing a FILDES command a subsequent rfc2292/bsd4.4 style packet (with at least
one dummy character) is sent to clamd carrying the file descriptor to be scanned
inside the ancillary data. Alternatively the file descriptor may be sent in the
same packet, including the extra character.

STATS It is mandatory to newline terminate this command, or prefix with n or z, it is
recommended to only use the z prefix.

Replies with statistics about the scan queue, contents of scan queue, and memory
usage. The exact reply format is subject to change in future releases.

IDSESSION, END
It is mandatory to prefix this command with n or z, and all commands inside
IDSESSION must be prefixed.

Start/end a clamd session. Within a session multiple SCAN, INSTREAM, FILDES,
VERSION, STATS commands can be sent on the same socket without opening new
connections. Replies from clamd will be in the form '<id>: <response>' where <id>
is the request number (in ascii, starting from 1) and <response> is the usual clamd
reply. The reply lines have same delimiter as the corresponding command had.
Clamd will process the commands asynchronously, and reply as soon as it has
finished processing.

Clamd requires clients to read all the replies it sent, before sending more
commands to prevent send() deadlocks. The recommended way to implement a client
that uses IDSESSION is with non-blocking sockets, and a select()/poll() loop:
whenever send would block, sleep in select/poll until either you can write more
data, or read more replies. Note that using non-blocking sockets without the
select/poll loop and alternating recv()/send() doesn't comply with clamd's
requirements.

If clamd detects that a client has deadlocked, it will close the connection. Note
that clamd may close an IDSESSION connection too if you don't follow the protocol's
requirements. The client can use the PING command to keep the connection alive.

VERSIONCOMMANDS
It is mandatory to prefix this command with either n or z. It is recommended to
use nVERSIONCOMMANDS.

Print program and database versions, followed by "| COMMANDS:" and a space-
delimited list of supported commands. Clamd <0.95 will recognize this as the
VERSION command, and reply only with their version, without the commands list.

This command can be used as an easy way to check for IDSESSION support for example.

DEPRECATED COMMANDS

STREAM Scan stream - on this command clamd will return "PORT number" you should connect to
and send data to scan. (DEPRECATED, use INSTREAM instead)

NOT SUPPORTED COMMANDS

SESSION, END
Start/end a clamd session which will allow you to run multiple commands per TCP
session. (use IDSESSION instead)

OPTIONS

       -h, --help
              Output help information and exit.

       -V, --version
              Print the version number and exit.

       -F, --foreground
              Run in foreground; do not daemonize.

       --debug
              Enable debug mode.

       -c FILE, --config-file=FILE
              Read configuration from FILE.

SIGNALS

       Clamd recognizes the following signals:

       SIGHUP Reopen the logfile.

       SIGUSR2
              Reload the signature databases.

       SIGTERM
              Perform a clean exit.

FILES

       /etc/clamav/clamd.conf

CREDITS

       Please check the full documentation for credits.

AUTHOR

       Tomasz Kojm <tkojm@clamav.net>