procmgr_event_notify_add()

Arguments:

flags

A bitwise OR of the type of events that you want to be notified of. The event types include:

• PROCMGR_EVENT_CONFSTR
• PROCMGR_EVENT_CONTIG_ALLOC_FAIL
• PROCMGR_EVENT_DAEMON_DEATH
• PROCMGR_EVENT_PATHSPACE
• PROCMGR_EVENT_PROCESS_CREATE
• PROCMGR_EVENT_PROCESS_DEATH
• PROCMGR_EVENT_SYNC
• PROCMGR_EVENT_SYSCONF
• PROCMGR_EVENT_TOD

For more information, see Event types, below.

event

A pointer to a sigevent structure that specifies how you want to be notified.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The procmgr_event_notify_add() function adds a request that the process manager notify the caller of the system-wide events identified by the given flags. You can use this function to set up more than one notification request. The application must register the event by calling MsgRegisterEvent() with SYSMGR_COID passed as the connection ID (coid).

To delete a request, call procmgr_event_notify_delete(), passing it the handle returned by procmgr_event_notify_add().

Event types

The following event types are defined in <sys/procmgr.h>:

PROCMGR_EVENT_CONFSTR

A process set a configuration string.

PROCMGR_EVENT_CONTIG_ALLOC_FAIL

An attempt to allocate contiguous memory failed.

PROCMGR_EVENT_DAEMON_DEATH

A process in session 1 died. This event is most useful for watching for the death of daemon processes that use procmgr_daemon() to put themselves in session 1 as well as close and redirect file descriptors. As a result of this closing and redirecting, the death of daemons is difficult to detect otherwise.

PROCMGR_EVENT_PATHSPACE

A resource manager added or removed an entry (i.e., mountpoint) to or from the pathname space. This is generally associated with resource manager calls to resmgr_attach() and resmgr_detach(). Terminating a resource manager process also generates this event if the mountpoints haven't been detached.

PROCMGR_EVENT_PROCESS_CREATE

A new process has been created.

PROCMGR_EVENT_PROCESS_DEATH

A process died.

PROCMGR_EVENT_SYNC

A process called sync() to synchronize the filesystems.

PROCMGR_EVENT_SYSCONF

A process set a system configuration string.

PROCMGR_EVENT_TOD

A process changed the time of day by calling ClockTime() or clock_settime().

If you set SIGEV_FLAG_UPDATEABLE in the hidden bits in the sigevent structure, the kernel provides some additional information in the sigev_value member:

The code for generating the hash of the pathname is as follows:

static unsigned pathspace_hash( const unsigned char *str ) {

    unsigned hash, x;

    for (x = hash = 0 ; *str ; ++str) {
        hash = (hash << 4) + *str;
        if ((x = hash & 0xf0000000u) != 0) {
            hash ^= (x >> 24);
            hash &= ~x;
        }
    }
    // Modification from standard ELFHash so that client can tell that the
    // sigev_value field contains a hash if it's non-zero
    return hash | 0x80000000u;

}

Returns:

An integer handle that you can pass to procmgr_event_notify_delete(), or -1 if an error occurred (errno is set).

Examples:

#include <ctype.h>
#include <devctl.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/neutrino.h>
#include <sys/procfs.h>
#include <sys/procmgr.h>

#define PROCESS_DIED_CODE   (_PULSE_CODE_MINAVAIL + 1)

int main( int argc, char **argv )
{
    int chid, coid, rc, handle;
    struct sigevent event;
    struct _pulse msg;

    chid = ChannelCreate( _NTO_CHF_PRIVATE );
    if (0 > chid) {
        fprintf( stderr, "ChannelCreate() failed : %s", strerror(errno) );
        exit( EXIT_FAILURE );
    }

    coid = ConnectAttach( 0, 0, chid, _NTO_SIDE_CHANNEL, _NTO_COF_CLOEXEC );
    if (0 > coid) {
        fprintf( stderr, "ConnectAttach() failed : %s", strerror(errno) );
        exit( EXIT_FAILURE );
    }

    SIGEV_PULSE_INIT( &event, coid, SIGEV_PULSE_PRIO_INHERIT, PROCESS_DIED_CODE, 0 );
    SIGEV_MAKE_UPDATEABLE( &event );

    if (0 != MsgRegisterEvent( &event, SYSMGR_COID )) {
        fprintf( stderr, "MsgRegisterEvent() failed : %s", strerror(errno) );
        exit( EXIT_FAILURE );
    }
    /*
     * Ask to be notified via a pulse whenever a process dies
     */
    handle = procmgr_event_notify_add( PROCMGR_EVENT_PROCESS_DEATH, &event );
    if (handle == -1) {
        fprintf( stderr, "procmgr_event_notify_add() failed : %s", strerror(errno) );
        exit( EXIT_FAILURE );
    }

    for(;;) {
        rc = MsgReceivePulse( chid, &msg, sizeof(msg), NULL );
        if (rc == -1) {
            fprintf( stderr, "MsgReceivePulse() failed : %s", strerror(errno) );
            exit( EXIT_FAILURE );
        }

        switch(msg.code) {
            case PROCESS_DIED_CODE:
                printf( "process pid:%i is no longer running\n", msg.value.sival_int );
                break;
        }
    }

    procmgr_event_notify_delete( handle );
    return 0;
}

Classification:

QNX OS