привилегированные услуги сборщика PCP (privileged PCP collector services)
Имя (Name)
pmdaRootConnect, pmdaRootShutdown, pmdaRootContainerHostName,
pmdaRootContainerProcessID, pmdaRootContainerCGroupName,
pmdaRootProcessStart, pmdaRootProcessWait,
pmdaRootProcessTerminate - privileged PCP collector services
Синопсис C (C Synopsis)
#include <pcp/pmapi.h>
#include <pcp/pmda.h>
int pmdaRootConnect(void);
void pmdaRootShutdown(int fd);
int pmdaRootContainerHostName(int fd, char *name, int namelen,
char *buffer, int buflen);
int pmdaRootContainerProcessID(int fd, char *name, int namelen);
int pmdaRootContainerCGroupName(int fd, char *name, int namelen,
char *buffer, int buflen);
int pmdaRootProcessStart(int fd, int ipctype, char *label, int
labellen, const char *args, int argslen, int *pid, int
*infd, int *outfd);
int pmdaRootProcessWait(int fd, int pid, int *status);
int pmdaRootProcessTerminate(int fd, int pid);
cc ... -lpcp_pmda -lpcp
Описание (Description)
pmdaRootConnect initializes an IPC channel between a PCP
collector process - either a PMDA(3) or pmcd(1) itself - and the
pmdaroot(1) server.
On success, the return value from pmdaRootConnect is a unix(7)
domain socket file descriptor, which can be subsequently passed
to each of the other APIs described here. This channel can be
used to perform limited privilege escalation for specific
scenarios needed by PCP collector services. The channel can be
deactivated using the pmdaRootShutdown interface.
Контейнеры (Containers)
Several interfaces are provided for access to the container
facilities of modern Linux distributions, as needed by various
agents accessing kernel features related to containers.
pmdaRootContainerHostName allows lookup of the current hostname
for a named container on behalf of an unprivileged process, via
the setns(3) system call on Linux. On success, the hostname is
returned in the supplied buffer, of size buflen and the return
value indicates the length of the hostname.
pmdaRootContainerProcessID performs a name to process identifier
translation - on success, the return value is the identifier of
the first process started (process 1) in the named container.
pmdaRootContainerCGroupName fills the supplied buffer with the
engine-specific names of kernel control groups that have been
used to build the container identified by name. When successful,
the return value indicates the length of the cgroup name resolved
for the container.
The name of the container is interpreted by pmdaroot(1), which
attempts to match up the specified name with one of the
implementations of containers that it is aware of. Hence, the
name argument is potentially interpreted differently, depending
on the installed container engine, as determined internally by
pmdaroot).
In the case of the Docker container engine, for example, a valid
container name can be the unique hash identifier, the human-
readable name, or any unique identifier substring. This is the
algorithm used by the Docker client tools themselves.
Процессы (Processes)
A second set of interfaces are provided allowing the collector
system to start privileged child processes. In particular, these
are used by pmcd(1) so that it can start privileged PMDAs even
when it is running under an unprivileged account itself.
These interfaces allow processes to be started
(pmdaRootProcessStart), reaped upon completion
(pmdaRootProcessWait), and forcibly terminated through use of
signals (pmdaRootProcessTerminate). At this stage, they are
intended only for use by pmcd itself and as such are described
here only for completeness.
Диагностика (Diagnostic)
All pmdaRoot interfaces will return negative status codes
suitable for passing to pmErrStr_r(3).
Смотри также (See also)
pmcd(1), pmdaroot(1), pmErrStr_r(3), PMDA(3), setns(3) and
unix(7).
