NAME

       sd_bus_query_sender_creds, sd_bus_query_sender_privilege - Query bus message sender
       credentials/privileges

SYNOPSIS

       #include <systemd/sd-bus.h>

       int sd_bus_query_sender_creds(sd_bus_message *m, uint64_t mask, sd_bus_creds **creds);

       sd_bus_error* sd_bus_query_sender_privilege(sd_bus_message *m, int capability);

DESCRIPTION

       sd_bus_query_sender_creds() returns the credentials of the message m. The mask parameter is a combo of
       SD_BUS_CREDS_* flags that indicate which credential info the caller is interested in. See
       sd_bus_creds_new_from_pid(3) for a list of possible flags. First, this message checks if the requested
       credentials are attached to the message itself. If not, but the message contains the pid of the sender
       and the caller specified the SD_BUS_CREDS_AUGMENT flag, this function tries to figure out the missing
       credentials via other means (starting from the pid). If the pid isn't available but the message has a
       sender, this function calls sd_bus_get_name_creds(3) to get the requested credentials. If the message has
       no sender (when a direct connection is used), this function calls sd_bus_get_owner_creds(3) to get the
       requested credentials. On success, the requested credentials are stored in creds. Ownership of the
       credentials object in creds is transferred to the caller and should be freed by calling
       sd_bus_creds_unref(3).

       sd_bus_query_sender_privilege() checks if the message m has the requested privileges. If capability is a
       non-negative integer, this function checks if the message has the capability with the same value. See
       capabilities(7) for a list of capabilities. If capability is a negative integer, this function returns
       whether the sender of the message runs as the same user as the receiver of the message, or if the sender
       of the message runs as root and the receiver of the message does not run as root. On success and if the
       message has the requested privileges, this function returns a positive integer. If the message does not
       have the requested privileges, this function returns zero.

RETURN VALUE

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

   Errors
       Returned errors may indicate the following problems:

       -EINVAL
           The message m or an output parameter is NULL.

           Added in version 246.

       -ENOTCONN
           The bus of m is not connected.

           Added in version 246.

       -ECHILD
           The bus of m was created in a different process, library or module instance.

           Added in version 246.

       -EPERM
           The message m is not sealed.

           Added in version 246.

NOTES

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

       The code described here uses getenv(3), which is declared to be not multi-thread-safe. This means that
       the code calling the functions described here must not call setenv(3) from a parallel thread. It is
       recommended to only do calls to setenv() from an early phase of the program when no other threads have
       been started.

HISTORY

       sd_bus_query_sender_creds() and sd_bus_query_sender_privilege() were added in version 246.

SEE ALSO

       systemd(1), sd-bus(3), sd_bus_creds_new_from_pid(3), sd_bus_get_name_creds(3), sd_bus_get_owner_creds(3),
       sd_bus_creds_unref(3), capabilities(7)