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)