pmdaattribute(3) [centos man page]

PMDAATTRIBUTE(3)					     Library Functions Manual						  PMDAATTRIBUTE(3)

NAME

       pmdaAttribute - informs a PMDA about client connection attributes

C SYNOPSIS

       #include <pcp/pmapi.h>
       #include <pcp/impl.h>
       #include <pcp/pmda.h>

       int pmdaAttribute(int context, int key, char *value, int length, pmdaExt *pmda);

       cc ... -lpcp_pmda -lpcp

DESCRIPTION

       As  part  of  the Performance Metrics Domain Agent (PMDA) API (see PMDA(3)), pmdaAttribute is the generic callback for responding to client
       connection attributes.  These attributes include client credential information, such as user ID and group ID.

       A PMDA that supports connection attributes will provide a private pmdaAttribute callback by  assignment	to  version.six.attribute  of  the
       pmdaInterface structure, and implement custom logic for any of the attribute key-value pairs of interest to it.

       All  attributes are associated with a specific client context, and these can be uniquely identified using the ctx first argument.  The PMDA
       should track client connections, and disconnections using the pmdaSetEndContextCallBack(3) interface, as a result.   The  pmdaGetContext(3)
       interface may be particularly helpful also.

       All  attributes	are  passed  as key-value pairs and the value is always passed as a null-terminated string of given length.  This includes
       numeric attributes like the user ID.

       The most commonly used attributes would be PCP_ATTR_USERID and  PCP_ATTR_GROUPID  but  others  may  also  be  optionally  passed  (such	as
       PCP_ATTR_USERNAME)  if  they  are  available.   Some  attributes  will  be  consumed  by  pmcd  and  never through passed to PMDAs, such as
       PCP_ATTR_PASSWORD.  A complete list of all possible attributes can be found in the headers listed above, all are prefixed by PCP_ATTR.

DIAGNOSTICS

       pmdaAttribute should return either zero on success, or a negative return code to indicate an error in handling the attribute.  This  return
       code  cannot  be  used  to indicate a client should be disallowed access - such functionality must be performed by the agent in response to
       callbacks for the client in question (using PM_ERR_PERMISSION for those specific callbacks, for that  specific  client.	 In  other  words,
       errors  will  be  be passed to PMCD but there is no guarantee made that the error will be return to the client and result in termination of
       the client, for example.

CAVEAT

       The PMDA must be using PMDA_PROTOCOL_6 or later, as specified in the call to pmdaDSO(3) or pmdaDaemon(3).

SEE ALSO

       PMAPI(3), PMDA(3), pmdaDaemon(3), pmdaDSO(3), pmdaMain(3) and pmdaGetContext(3).

Performance Co-Pilot							PCP							  PMDAATTRIBUTE(3)

Check Out this Related Man Page

PMDACONNECT(3)						     Library Functions Manual						    PMDACONNECT(3)

NAME

       pmdaConnect - establish a connection between a daemon PMDA and PMCD

C SYNOPSIS

       #include <pcp/pmapi.h>
       #include <pcp/impl.h>
       #include <pcp/pmda.h>

       void pmdaConnect(pmdaInterface *dispatch);

       cc ... -lpcp_pmda -lpcp

DESCRIPTION

       pmdaConnect  initializes  an IPC channel between a PMDA(3) and the pmcd(1) process on the local host.  The type of the connection is depen-
       dent on the e_io field of the pmdaExt structure:

       pmdaPipe       Use stdin/stdout to communicate; assumes this is a pipe created by pmcd before the PMDA(3) was launched.

       pmdaInet       Assume pmcd(1) will establish a connection to an IPv4 internet domain socket set up by the PMDA(3).  The name or	number	of
		      the port must be specified in the e_sockname or e_port fields of the pmdaExt structure, respectively.

       pmdaIPv6       Assume  pmcd(1)  will establish a connection to an IPv6 internet domain socket set up by the PMDA(3).  The name or number of
		      the port must be specified in the e_sockname or e_port fields of the pmdaExt structure, respectively.

       pmdaUnix       Assume pmcd(1) will establish a connection to a unix domain socket set up by the PMDA(3).  The port number must be specified
		      in the e_port field of the pmdaExt structure.

       pmdaUnknown    The initial value of e_io which defaults to using stdin/stdout.

       The  relevant  pmdaExt  fields  are  initialized by pmdaInit(3) and set by pmdaGetOpt(3), so most PMDAs should not need to access or modify
       them.

DIAGNOSTICS

       pmdaConnect will log the type of connection made to pmcd(1) if the PMAPI(3) debug control variable (pmDebug) has the DBG_TRACE_LIBPMDA flag
       set.

       If an error occurs that is unrecoverable, dispatch->status is set to a value less than 0, otherwise it is zero or positive.

CAVEAT

       The PMDA must be using PMDA_INTERFACE_2 or later, as specified in the call to pmdaDaemon(3).

SEE ALSO

       pmcd(1), pipe(2), socket(2), PMAPI(3), PMDA(3), pmdaDaemon(3), pmdaGetOpt(3) and pmdaInit(3).

Performance Co-Pilot							PCP							    PMDACONNECT(3)

Linux and UNIX Man Pages

pmdaattribute(3) [centos man page]

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