NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | NOTES | SEE ALSO | COLOPHON

SD_BUS_NEGOTIATE_FDS(3)     sd_bus_negotiate_fds     SD_BUS_NEGOTIATE_FDS(3)

NAME         top

       sd_bus_negotiate_fds, sd_bus_negotiate_timestamp,
       sd_bus_negotiate_creds - Control feature negotiation on bus
       connections

SYNOPSIS         top

       #include <systemd/sd-bus.h>

       int sd_bus_negotiate_fds(sd_bus *bus, int b);

       int sd_bus_negotiate_timestamp(sd_bus *bus, int b);

       int sd_bus_negotiate_creds(sd_bus *bus, int b, uint64_t mask);

DESCRIPTION         top

       sd_bus_negotiate_fds() controls whether file descriptor passing shall
       be negotiated for the specified bus connection. It takes a bus object
       and a boolean, which, when true, enables file descriptor passing,
       and, when false, disables it. Note that not all transports and
       servers support file descriptor passing. In particular, networked
       transports generally do not support file descriptor passing. To find
       out whether file descriptor passing is available after negotiation,
       use sd_bus_can_send(3) and pass SD_BUS_TYPE_UNIX_FD. Note that file
       descriptor passing is always enabled for both sending and receiving
       or for neither, but never only in one direction. By default, file
       descriptor passing is negotiated for all connections.

       Note that when bus activation is used, it is highly recommended to
       set the AcceptFileDescriptors= setting in the .busname unit file to
       the same setting as negotiated by the program ultimately activated.
       By default, file descriptor passing is enabled for both.

       sd_bus_negotiate_timestamp() controls whether implicit sender
       timestamps shall be attached automatically to all incoming messages.
       Takes a bus object and a boolean, which, when true, enables
       timestamping, and, when false, disables it. Use
       sd_bus_message_get_monotonic_usec(3),
       sd_bus_message_get_realtime_usec(3), sd_bus_message_get_seqnum(3) to
       query the timestamps of incoming messages. If negotiation is disabled
       or not supported, these calls will fail with -ENODATA. Note that
       currently no transports support timestamping of messages. By default,
       message timestamping is not negotiated for connections.

       sd_bus_negotiate_creds() controls whether and which implicit sender
       credentials shall be attached automatically to all incoming messages.
       Takes a bus object and a boolean indicating whether to enable or
       disable the credential parts encoded in the bit mask value argument.
       Note that not all transports support attaching sender credentials to
       messages, or do not support all types of sender credential
       parameters, or might suppress them under certain circumstances for
       individual messages. Specifically, dbus1 only supports
       SD_BUS_CREDS_UNIQUE_NAME. The sender credentials are suitable for
       authorization decisions. By default, only
       SD_BUS_CREDS_WELL_KNOWN_NAMES and SD_BUS_CREDS_UNIQUE_NAME are
       enabled. In fact, these two credential fields are always sent along
       and cannot be turned off.

       The sd_bus_negotiate_fds() function may be called only before the
       connection has been started with sd_bus_start(3). Both
       sd_bus_negotiate_timestamp() and sd_bus_negotiate_creds() may also be
       called after a connection has been set up. Note that, when operating
       on a connection that is shared between multiple components of the
       same program (for example via sd_bus_default(3)), it is highly
       recommended to only enable additional per message metadata fields,
       but never disable them again, in order not to disable functionality
       needed by other components.

RETURN VALUE         top

       On success, these functions return 0 or a positive integer. On
       failure, they return a negative errno-style error code.

ERRORS         top

       Returned errors may indicate the following problems:

       -EPERM
           The bus connection has already been started.

NOTES         top

       sd_bus_negotiate_fds() and the other functions described here are
       available as a shared library, which can be compiled and linked to
       with the libsystemd pkg-config(1) file.

SEE ALSO         top

       systemd(1), sd-bus(3), sd_bus_start(3), sd_bus_message_can_send(3),
       sd_bus_message_get_monotonic_usec(3),
       sd_bus_message_get_realtime_usec(3), sd_bus_message_get_seqnum(3),
       sd_bus_message_get_creds(3), systemd.busname(5)

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have a bug
       report for this manual page, see 
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.  This
       page was obtained from the project's upstream Git repository 
       ⟨https://github.com/systemd/systemd.git⟩ on 2017-09-15.  If you dis‐
       cover any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

systemd 234                                          SD_BUS_NEGOTIATE_FDS(3)

Pages that refer to this page: sd-bus(3)sd_bus_message_get_monotonic_usec(3)systemd.directives(7)systemd.index(7)