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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | NOTES | COLOPHON |
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SD_BUS_CREDS_GET_PID(3) sd_bus_creds_get_pid SD_BUS_CREDS_GET_PID(3)
sd_bus_creds_get_pid, sd_bus_creds_get_pidfd_dup,
sd_bus_creds_get_ppid, sd_bus_creds_get_tid, sd_bus_creds_get_uid,
sd_bus_creds_get_euid, sd_bus_creds_get_suid,
sd_bus_creds_get_fsuid, sd_bus_creds_get_gid,
sd_bus_creds_get_egid, sd_bus_creds_get_sgid,
sd_bus_creds_get_fsgid, sd_bus_creds_get_supplementary_gids,
sd_bus_creds_get_comm, sd_bus_creds_get_tid_comm,
sd_bus_creds_get_exe, sd_bus_creds_get_cmdline,
sd_bus_creds_get_cgroup, sd_bus_creds_get_unit,
sd_bus_creds_get_slice, sd_bus_creds_get_user_unit,
sd_bus_creds_get_user_slice, sd_bus_creds_get_session,
sd_bus_creds_get_owner_uid, sd_bus_creds_has_effective_cap,
sd_bus_creds_has_permitted_cap, sd_bus_creds_has_inheritable_cap,
sd_bus_creds_has_bounding_cap, sd_bus_creds_get_selinux_context,
sd_bus_creds_get_audit_session_id,
sd_bus_creds_get_audit_login_uid, sd_bus_creds_get_tty,
sd_bus_creds_get_unique_name, sd_bus_creds_get_well_known_names,
sd_bus_creds_get_description - Retrieve fields from a credentials
object
#include <systemd/sd-bus.h>
int sd_bus_creds_get_pid(sd_bus_creds *c, pid_t *pid);
int sd_bus_creds_get_pidfd_dup(sd_bus_creds *c, int *ret_fd);
int sd_bus_creds_get_ppid(sd_bus_creds *c, pid_t *ppid);
int sd_bus_creds_get_tid(sd_bus_creds *c, pid_t *tid);
int sd_bus_creds_get_uid(sd_bus_creds *c, uid_t *uid);
int sd_bus_creds_get_euid(sd_bus_creds *c, uid_t *uid);
int sd_bus_creds_get_suid(sd_bus_creds *c, uid_t *uid);
int sd_bus_creds_get_fsuid(sd_bus_creds *c, uid_t *uid);
int sd_bus_creds_get_gid(sd_bus_creds *c, gid_t *gid);
int sd_bus_creds_get_egid(sd_bus_creds *c, gid_t *gid);
int sd_bus_creds_get_sgid(sd_bus_creds *c, gid_t *gid);
int sd_bus_creds_get_fsgid(sd_bus_creds *c, gid_t *gid);
int sd_bus_creds_get_supplementary_gids(sd_bus_creds *c,
const gid_t **gids);
int sd_bus_creds_get_comm(sd_bus_creds *c, const char **comm);
int sd_bus_creds_get_tid_comm(sd_bus_creds *c, const char **comm);
int sd_bus_creds_get_exe(sd_bus_creds *c, const char **exe);
int sd_bus_creds_get_cmdline(sd_bus_creds *c, char ***cmdline);
int sd_bus_creds_get_cgroup(sd_bus_creds *c, const char **cgroup);
int sd_bus_creds_get_unit(sd_bus_creds *c, const char **unit);
int sd_bus_creds_get_slice(sd_bus_creds *c, const char **slice);
int sd_bus_creds_get_user_unit(sd_bus_creds *c,
const char **unit);
int sd_bus_creds_get_user_slice(sd_bus_creds *c,
const char **slice);
int sd_bus_creds_get_session(sd_bus_creds *c, const char **slice);
int sd_bus_creds_get_owner_uid(sd_bus_creds *c, uid_t *uid);
int sd_bus_creds_has_effective_cap(sd_bus_creds *c,
int capability);
int sd_bus_creds_has_permitted_cap(sd_bus_creds *c,
int capability);
int sd_bus_creds_has_inheritable_cap(sd_bus_creds *c,
int capability);
int sd_bus_creds_has_bounding_cap(sd_bus_creds *c,
int capability);
int sd_bus_creds_get_selinux_context(sd_bus_creds *c,
const char **context);
int sd_bus_creds_get_audit_session_id(sd_bus_creds *c,
uint32_t *sessionid);
int sd_bus_creds_get_audit_login_uid(sd_bus_creds *c,
uid_t *loginuid);
int sd_bus_creds_get_tty(sd_bus_creds *c, const char **tty);
int sd_bus_creds_get_unique_name(sd_bus_creds *c,
const char **name);
int sd_bus_creds_get_well_known_names(sd_bus_creds *c,
char ***name);
int sd_bus_creds_get_description(sd_bus_creds *c,
const char **name);
These functions return credential information from an sd_bus_creds
object. Credential objects may be created with
sd_bus_creds_new_from_pid(3), in which case they describe the
credentials of the process identified by the specified PID, with
sd_bus_get_name_creds(3), in which case they describe the
credentials of a bus peer identified by the specified bus name,
with sd_bus_get_owner_creds(3), in which case they describe the
credentials of the creator of a bus, or with
sd_bus_message_get_creds(3), in which case they describe the
credentials of the sender of the message.
Not all credential fields are part of every "sd_bus_creds" object.
Use sd_bus_creds_get_mask(3) to determine the mask of fields
available.
sd_bus_creds_get_pid() will retrieve the PID (process identifier).
Similarly, sd_bus_creds_get_ppid() will retrieve the parent PID.
Note that PID 1 has no parent process, in which case -ENXIO is
returned.
sd_bus_creds_get_pidfd_dup() will retrieve the PID file descriptor
(pidfd), see pidfd_open(2) for details. The file descriptor is
duplicated and thus must be closed by the caller.
sd_bus_creds_get_tid() will retrieve the TID (thread identifier).
sd_bus_creds_get_uid() will retrieve the numeric UID (user
identifier). Similarly, sd_bus_creds_get_euid() returns the
effective UID, sd_bus_creds_get_suid() the saved UID and
sd_bus_creds_get_fsuid() the file system UID.
sd_bus_creds_get_gid() will retrieve the numeric GID (group
identifier). Similarly, sd_bus_creds_get_egid() returns the
effective GID, sd_bus_creds_get_sgid() the saved GID and
sd_bus_creds_get_fsgid() the file system GID.
sd_bus_creds_get_supplementary_gids() will retrieve the
supplementary GIDs list.
sd_bus_creds_get_comm() will retrieve the comm field (truncated
name of the executable, as stored in /proc/pid/comm).
sd_bus_creds_get_tid_comm() will retrieve the comm field of the
thread (as stored in /proc/pid/task/tid/comm).
sd_bus_creds_get_exe() will retrieve the path to the program
executable (as stored in the /proc/pid/exe link, but with the "
(deleted)" suffix removed). Note that kernel threads do not have
an executable path, in which case -ENXIO is returned. Note that
this property should not be used for more than explanatory
information, in particular it should not be used for
security-relevant decisions. That's because the executable might
have been replaced or removed by the time the value can be
processed. Moreover, the kernel exports this information in an
ambiguous way (i.e. a deleted executable cannot be safely
distinguished from one whose name suffix is " (deleted)").
sd_bus_creds_get_cmdline() will retrieve an array of command line
arguments (as stored in /proc/pid/cmdline). Note that kernel
threads do not have a command line, in which case -ENXIO is
returned.
sd_bus_creds_get_cgroup() will retrieve the control group path.
See Control Groups v2[1].
sd_bus_creds_get_unit() will retrieve the systemd unit name (in
the system instance of systemd) that the process is a part of. See
systemd.unit(5). For processes that are not part of a unit,
returns -ENXIO.
sd_bus_creds_get_user_unit() will retrieve the systemd unit name
(in the user instance of systemd) that the process is a part of.
See systemd.unit(5). For processes that are not part of a user
unit, returns -ENXIO.
sd_bus_creds_get_slice() will retrieve the systemd slice (a unit
in the system instance of systemd) that the process is a part of.
See systemd.slice(5). Similarly, sd_bus_creds_get_user_slice()
retrieves the systemd slice of the process, in the user instance
of systemd.
sd_bus_creds_get_session() will retrieve the identifier of the
login session that the process is a part of. Please note the login
session may be limited to a stub process or two. User processes
may instead be started from their systemd user manager, e.g. GUI
applications started using DBus activation, as well as service
processes which are shared between multiple logins of the same
user. For processes that are not part of a session, returns
-ENXIO.
sd_bus_creds_get_owner_uid() will retrieve the numeric UID (user
identifier) of the user who owns the user unit or login session
that the process is a part of. See systemd-logind.service(8). For
processes that are not part of a user unit or session, returns
-ENXIO.
sd_bus_creds_has_effective_cap() will check whether the capability
specified by capability was set in the effective capabilities
mask. A positive return value means that it was set, zero means
that it was not set, and a negative return value indicates an
error. See capabilities(7) and the AmbientCapabilities= and
CapabilityBoundingSet= settings in systemd.exec(5).
sd_bus_creds_has_permitted_cap() is similar to
sd_bus_creds_has_effective_cap(), but will check the permitted
capabilities mask.
sd_bus_creds_has_inheritable_cap() is similar to
sd_bus_creds_has_effective_cap(), but will check the inheritable
capabilities mask.
sd_bus_creds_has_bounding_cap() is similar to
sd_bus_creds_has_effective_cap(), but will check the bounding
capabilities mask.
sd_bus_creds_get_selinux_context() will retrieve the SELinux
security context (label) of the process.
sd_bus_creds_get_audit_session_id() will retrieve the audit
session identifier of the process. Returns -ENXIO for processes
that are not part of an audit session.
sd_bus_creds_get_audit_login_uid() will retrieve the audit user
login identifier (the identifier of the user who is "responsible"
for the session). Returns -ENXIO for processes that are not part
of an audit session.
sd_bus_creds_get_tty() will retrieve the controlling TTY, without
the prefixing "/dev/". Returns -ENXIO for processes that have no
controlling TTY.
sd_bus_creds_get_unique_name() will retrieve the D-Bus unique
name. See The D-Bus specification[2].
sd_bus_creds_get_well_known_names() will retrieve the set of D-Bus
well-known names. See The D-Bus specification[2].
sd_bus_creds_get_description() will retrieve a descriptive name of
the bus connection of the peer. This name is useful to discern
multiple bus connections by the same peer, and may be altered by
the peer with the sd_bus_set_description(3) call.
All functions that take a const char** parameter will store the
answer there as an address of a NUL-terminated string. It will be
valid as long as c remains valid, and should not be freed or
modified by the caller.
All functions that take a char*** parameter will store the answer
there as an address of an array of strings. Each individual string
is NUL-terminated, and the array is NULL-terminated as a whole. It
will be valid as long as c remains valid, and should not be freed
or modified by the caller.
On success, these calls return 0 or a positive integer. On
failure, these calls return a negative errno-style error code.
Errors
Returned errors may indicate the following problems:
-ENODATA
The given field is not available in the credentials object c.
-ENXIO
The given field is not specified for the described process or
peer. This will be returned by sd_bus_creds_get_unit(),
sd_bus_creds_get_slice(), sd_bus_creds_get_user_unit(),
sd_bus_creds_get_user_slice(), and sd_bus_creds_get_session()
if the process is not part of a systemd system unit, systemd
user unit, systemd slice, or logind session. It will be
returned by sd_bus_creds_get_owner_uid() if the process is not
part of a systemd user unit or logind session. It will also be
returned by sd_bus_creds_get_exe() and
sd_bus_creds_get_cmdline() for kernel threads (since these are
not started from an executable binary, nor have a command
line), and by sd_bus_creds_get_audit_session_id() and
sd_bus_creds_get_audit_login_uid() when the process is not
part of an audit session, and sd_bus_creds_get_tty() if the
process has no controlling TTY.
-EINVAL
Specified pointer parameter is NULL.
-ENOMEM
Memory allocation failed.
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_get_pid(), sd_bus_creds_get_tid(),
sd_bus_creds_get_gid(), sd_bus_creds_get_comm(),
sd_bus_creds_get_tid_comm(), sd_bus_creds_get_exe(),
sd_bus_creds_get_cmdline(), sd_bus_creds_get_cgroup(),
sd_bus_creds_get_unit(), sd_bus_creds_get_user_unit(),
sd_bus_creds_get_slice(), sd_bus_creds_get_session(),
sd_bus_creds_get_owner_uid(), sd_bus_creds_has_effective_cap(),
sd_bus_creds_has_permitted_cap(),
sd_bus_creds_has_inheritable_cap(),
sd_bus_creds_has_bounding_cap(),
sd_bus_creds_get_selinux_context(),
sd_bus_creds_get_audit_session_id(),
sd_bus_creds_get_audit_login_uid(),
sd_bus_creds_get_unique_name(),
sd_bus_creds_get_well_known_names(), sd_bus_creds_get_ppid(),
sd_bus_creds_get_uid(), sd_bus_creds_get_euid(),
sd_bus_creds_get_suid(), sd_bus_creds_get_fsuid(),
sd_bus_creds_get_egid(), sd_bus_creds_get_sgid(),
sd_bus_creds_get_fsgid(), sd_bus_creds_get_supplementary_gids(),
sd_bus_creds_get_tty(), sd_bus_creds_get_description(), and
sd_bus_creds_get_user_slice() were added in version 221.
sd_bus_creds_get_pidfd_dup() was added in version 256.
systemd(1), sd-bus(3), sd_bus_creds_new_from_pid(3), fork(2),
execve(2), credentials(7), free(3), proc(5),
systemd.journal-fields(7)
1. Control Groups v2
https://docs.kernel.org/admin-guide/cgroup-v2.html
2. The D-Bus specification
https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus
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 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-08-11.) If you discover 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 258~rc2 SD_BUS_CREDS_GET_PID(3)
Pages that refer to this page: sd-bus(3), sd_bus_creds_new_from_pid(3), systemd.directives(7), systemd.index(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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