sd_bus_creds_new_from_pid, sd_bus_creds_new_from_pidfd, sd_bus_creds_get_mask, sd_bus_creds_get_augmented_mask, sd_bus_creds_ref, sd_bus_creds_unref, sd_bus_creds_unrefp — Retrieve credentials object for the specified PID
#include <systemd/sd-bus.h>
int sd_bus_creds_new_from_pid( | pid_t pid, |
uint64_t creds_mask, | |
sd_bus_creds **ret) ; |
int sd_bus_creds_new_from_pidfd( | int pidfd, |
uint64_t creds_mask, | |
sd_bus_creds **ret) ; |
uint64_t sd_bus_creds_get_mask( | sd_bus_creds *c) ; |
uint64_t sd_bus_creds_get_augmented_mask( | sd_bus_creds *c) ; |
sd_bus_creds *sd_bus_creds_ref( | sd_bus_creds *c) ; |
sd_bus_creds *sd_bus_creds_unref( | sd_bus_creds *c) ; |
void sd_bus_creds_unrefp( | sd_bus_creds **c) ; |
SD_BUS_CREDS_PID
,
SD_BUS_CREDS_PPID
,
SD_BUS_CREDS_TID
,
SD_BUS_CREDS_UID
,
SD_BUS_CREDS_EUID
,
SD_BUS_CREDS_SUID
,
SD_BUS_CREDS_FSUID
,
SD_BUS_CREDS_GID
,
SD_BUS_CREDS_EGID
,
SD_BUS_CREDS_SGID
,
SD_BUS_CREDS_FSGID
,
SD_BUS_CREDS_SUPPLEMENTARY_GIDS
,
SD_BUS_CREDS_COMM
,
SD_BUS_CREDS_TID_COMM
,
SD_BUS_CREDS_EXE
,
SD_BUS_CREDS_CMDLINE
,
SD_BUS_CREDS_CGROUP
,
SD_BUS_CREDS_UNIT
,
SD_BUS_CREDS_SLICE
,
SD_BUS_CREDS_USER_UNIT
,
SD_BUS_CREDS_USER_SLICE
,
SD_BUS_CREDS_SESSION
,
SD_BUS_CREDS_OWNER_UID
,
SD_BUS_CREDS_EFFECTIVE_CAPS
,
SD_BUS_CREDS_PERMITTED_CAPS
,
SD_BUS_CREDS_INHERITABLE_CAPS
,
SD_BUS_CREDS_BOUNDING_CAPS
,
SD_BUS_CREDS_SELINUX_CONTEXT
,
SD_BUS_CREDS_AUDIT_SESSION_ID
,
SD_BUS_CREDS_AUDIT_LOGIN_UID
,
SD_BUS_CREDS_TTY
,
SD_BUS_CREDS_UNIQUE_NAME
,
SD_BUS_CREDS_WELL_KNOWN_NAMES
,
SD_BUS_CREDS_DESCRIPTION
,
SD_BUS_CREDS_PIDFD
,
SD_BUS_CREDS_AUGMENT
,
_SD_BUS_CREDS_ALL
sd_bus_creds_new_from_pid()
creates a
new credentials object and fills it with information about the
process pid
. The pointer to this object
will be stored in the ret
pointer. Note that
credential objects may also be created and retrieved via
sd_bus_get_name_creds(3),
sd_bus_get_owner_creds(3)
and
sd_bus_message_get_creds(3).
sd_bus_creds_new_from_pidfd()
is identical to
sd_bus_creds_new_from_pid()
, but takes a PID file descriptor rather than a numeric
PID as reference to the process. See pidfd_open(2).
The information that will be stored is determined by creds_mask
. It may
contain a subset of ORed constants SD_BUS_CREDS_PID
,
SD_BUS_CREDS_PPID
, SD_BUS_CREDS_TID
,
SD_BUS_CREDS_UID
, SD_BUS_CREDS_EUID
,
SD_BUS_CREDS_SUID
, SD_BUS_CREDS_FSUID
,
SD_BUS_CREDS_GID
, SD_BUS_CREDS_EGID
,
SD_BUS_CREDS_SGID
, SD_BUS_CREDS_FSGID
,
SD_BUS_CREDS_SUPPLEMENTARY_GIDS
, SD_BUS_CREDS_COMM
,
SD_BUS_CREDS_TID_COMM
, SD_BUS_CREDS_EXE
,
SD_BUS_CREDS_CMDLINE
, SD_BUS_CREDS_CGROUP
,
SD_BUS_CREDS_UNIT
, SD_BUS_CREDS_SLICE
,
SD_BUS_CREDS_USER_UNIT
, SD_BUS_CREDS_USER_SLICE
,
SD_BUS_CREDS_SESSION
, SD_BUS_CREDS_OWNER_UID
,
SD_BUS_CREDS_EFFECTIVE_CAPS
, SD_BUS_CREDS_PERMITTED_CAPS
,
SD_BUS_CREDS_INHERITABLE_CAPS
, SD_BUS_CREDS_BOUNDING_CAPS
,
SD_BUS_CREDS_SELINUX_CONTEXT
, SD_BUS_CREDS_AUDIT_SESSION_ID
,
SD_BUS_CREDS_AUDIT_LOGIN_UID
, SD_BUS_CREDS_TTY
,
SD_BUS_CREDS_UNIQUE_NAME
, SD_BUS_CREDS_WELL_KNOWN_NAMES
,
SD_BUS_CREDS_DESCRIPTION
, and SD_BUS_CREDS_PIDFD
. Use the
special value _SD_BUS_CREDS_ALL
to request all supported fields. The
SD_BUS_CREDS_AUGMENT
constant may not be ORed into the mask for invocations of
sd_bus_creds_new_from_pid()
or
sd_bus_creds_new_from_pidfd()
.
Fields can be retrieved from the credentials object using sd_bus_creds_get_pid(3) and other functions which correspond directly to the constants listed above.
A mask of fields which were actually successfully retrieved can be retrieved with
sd_bus_creds_get_mask()
. If the credentials object was created with
sd_bus_creds_new_from_pid()
or sd_bus_creds_new_from_pidfd()
,
this will be a subset of fields requested in creds_mask
.
Similar to sd_bus_creds_get_mask()
, the function
sd_bus_creds_get_augmented_mask()
returns a bitmask of field constants. The mask
indicates which credential fields have been retrieved in a non-atomic fashion. For credential objects
created via sd_bus_creds_new_from_pid()
or
sd_bus_creds_new_from_pidfd()
, this mask will be identical to the mask returned by
sd_bus_creds_get_mask()
. However, for credential objects retrieved via
sd_bus_get_name_creds()
, this mask will be set for the credential fields that could
not be determined atomically at peer connection time, and which were later added by reading augmenting
credential data from /proc/
. Similarly, for credential objects retrieved via
sd_bus_get_owner_creds()
, the mask is set for the fields that could not be
determined atomically at bus creation time, but have been augmented. Similarly, for credential objects
retrieved via sd_bus_message_get_creds()
, the mask is set for the fields that could
not be determined atomically at message sending time, but have been augmented. The mask returned by
sd_bus_creds_get_augmented_mask()
is always a subset of (or identical to) the mask
returned by sd_bus_creds_get_mask()
for the same object. The latter call hence
returns all credential fields available in the credential object, the former then marks the subset of
those that have been augmented. Note that augmented fields are unsuitable for authorization decisions, as
they may be retrieved at different times, thus being subject to races. Hence, augmented fields should be
used exclusively for informational purposes.
sd_bus_creds_ref()
creates a new
reference to the credentials object c
. This
object will not be destroyed until
sd_bus_creds_unref()
has been called as many
times plus once more. Once the reference count has dropped to zero,
c
cannot be used anymore, so further
calls to sd_bus_creds_ref(c)
or
sd_bus_creds_unref(c)
are illegal.
sd_bus_creds_unref()
destroys a reference
to c
.
sd_bus_creds_unrefp()
is similar to
sd_bus_creds_unref()
but takes a pointer to a
pointer to an sd_bus_creds object. This call is useful in
conjunction with GCC's and LLVM's Clean-up
Variable Attribute. Note that this function is defined as
inline function.
sd_bus_creds_ref()
,
sd_bus_creds_unref()
and
sd_bus_creds_unrefp()
execute no operation if
the passed in bus credentials object is
NULL
.
On success, sd_bus_creds_new_from_pid()
and
sd_bus_creds_new_from_pidfd()
return 0 or a positive integer. On failure, they return
a negative errno-style error code.
sd_bus_creds_get_mask()
returns the
mask of successfully acquired fields.
sd_bus_creds_get_augmented_mask()
returns the mask of fields that have been augmented from data in
/proc/
, and are thus not suitable for
authorization decisions.
sd_bus_creds_ref()
always returns the
argument.
sd_bus_creds_unref()
always returns
NULL
.
The functions sd_bus_creds_new_from_pid()
and
sd_bus_creds_new_from_pidfd()
create a new object and the caller owns the sole
reference. When not needed anymore, this reference should be destroyed with
sd_bus_creds_unref(3).
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.
sd_bus_creds_new_from_pid()
,
sd_bus_creds_get_mask()
,
sd_bus_creds_ref()
,
sd_bus_creds_unref()
, and
sd_bus_creds_get_augmented_mask()
were added in version 221.
sd_bus_creds_unrefp()
was added in version 229.
sd_bus_creds_new_from_pidfd()
was added in version 256.