prom_process_osx.c

// Phil Budne
// 2020-04-17
//
// prometheus process vars for OSX
// (pretty much) just the standard values defined at:
// https://prometheus.io/docs/instrumenting/writing_clientlibs/#process-metrics

/*-
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2020, Philip L. Budne
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <sys/types.h>			/* pid_t */

#include <mach/task.h>
#include <mach/mach_init.h>

#include <string.h>			/* strncmp */
#include <time.h>			/* time(), time_t */
#include <unistd.h>			/* getpid() */

#include "prom.h"
#include "common.h"

////////////////

static double rss, vsz;
static time_t last_proc;

static int
_read_proc(void) {
    static task_t task;
    mach_task_basic_info_data_t mtbi;
    mach_msg_type_number_t mtbic;
    
    if (!STALE(last_proc))
	return 0;

    if (!task) {
	if (task_for_pid(current_task(), getpid(), &task) != KERN_SUCCESS)
	    return -1;
    }

    // thanks to miknight.blogspot.com/2005/11/resident-set-size-in-mac-os-x.html for a start!
    mtbic = MACH_TASK_BASIC_INFO_COUNT;
    if (task_info(task, MACH_TASK_BASIC_INFO, (task_info_t)&mtbi, &mtbic) != KERN_SUCCESS)
	return -1;
    rss = mtbi.resident_size;
    vsz = mtbi.virtual_size;

    last_proc = prom_now;
    return 0;
}

static int
read_proc(void) {
    int ret;
    DECLARE_LOCK(read_proc_lock);

    if (!STALE(last_proc))
	return 0;

    LOCK(read_proc_lock);
    ret = _read_proc();
    UNLOCK(read_proc_lock);
    return ret;
}

////////////////////////////////////////////////////////////////
// implement variables

PROM_GETTER_GAUGE_FN(process_virtual_memory_bytes,
		     "Virtual memory size in bytes") {
    if (read_proc() < 0)
	return 0.0;
    return vsz;
}

////////////////
PROM_GETTER_GAUGE_FN(process_resident_memory_bytes,
		     "Resident memory size in bytes") {
    if (read_proc() < 0)
	return 0.0;
    return rss;				/* XXX */
}

////////////////
// not in the process_ namespace
#if 0
PROM_GETTER_GAUGE_FN(num_threads,
		     "Number of process threads") {
    if (read_proc() < 0)
	return 0.0;
    return threads;
}
#endif

////////////////

// no-op call this to force loading this file
int
prom_process_init(void) {
    return prom_process_common_init();
}