and-Linux.c

/*
    AND auto nice daemon - renice programs according to their CPU usage.
    Copyright (C) 1999-2003 Patrick Schemitz <schemitz@users.sourceforge.net>
    http://and.sourceforge.net/

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <unistd.h>
#include <string.h>
#include <dirent.h>
#include <ctype.h>
#include <syslog.h>
#include <sys/stat.h>
#include <signal.h>
#include <asm/param.h> /* kernel interrupt frequency: HZ */

#include "and.h"

/*
    AND -- auto-nice daemon/Linux version.

    Linux-specific AND version. Makes excessive use of the Linux
    /proc filesystem and is not portable.

    1999-2003 Patrick Schemitz, <schemitz@users.sourceforge.net>
    http://and.sourceforge.net/
*/

static DIR *linux_procdir = 0;
static struct and_procent linux_proc;

/*
    Scan /proc/<pid>/stat file. Format described in proc(5).
    l1: pid comm state ppid
    l2: pgrp session tty tpgid
    l3: flags minflt cminflt majflt cmajflt
    l4: utime stime cutime cstime
    l5: counter priority
*/
int linux_readproc (char *fn)
{
	FILE* f;
	int i;
	long li;
	long unsigned u, ujf, sjf;
	char state;
	char buffer [1024];
	if (!(f = fopen(fn,"rt"))) return 0;
	fscanf(f,"%d %1023s %c %d",&(linux_proc.pid),buffer,&state,&(linux_proc.ppid));
	fscanf(f,"%d %d %d %d",&i,&i,&i,&i);
	fscanf(f,"%lu %lu %lu %lu %lu",&u,&u,&u,&u,&u);
	fscanf(f,"%lu %lu %ld %ld",&ujf,&sjf,&li,&li);
	fscanf(f,"%ld %d",&li,&(linux_proc.nice));
	i = feof(f);
	fclose(f);
	if (i) return 0;
	if (state == 'Z') return 0;			/* ignore zombies */
	ujf += sjf;					/* take into account both usr and sys time */
	ujf /= HZ;					/* convert jiffies to seconds */
	linux_proc.utime = ujf > INT_MAX ? INT_MAX: (int) ujf;
	buffer[strlen(buffer)-1] = 0;			/* remove () around command name */
	strncpy(linux_proc.command,&buffer[1],1023);
	linux_proc.command[1023] = 0;
	and_printf(3, "Linux: process %s pid: %d ppid: %d\n",
		   linux_proc.command, linux_proc.pid, linux_proc.ppid);
	return 1;
}

struct and_procent *linux_getnext ()
{
	char name [1024];
	struct dirent *entry;
	struct stat dirstat;
	if (!linux_procdir) return NULL;
	while ((entry = readdir(linux_procdir)) != NULL) { /* omit . .. apm bus... */
		if (isdigit(entry->d_name[0])) break;
	}
	if (!entry) return NULL;
	/* stat() /proc/<pid> directory to get uid/gid */
	snprintf(name, 1024, "/proc/%s",entry->d_name);
	if (stat(name,&dirstat)) return linux_getnext();
	/* read the job's stat "file" to get command, nice level, etc */
	snprintf(name, 1024, "/proc/%s/stat",entry->d_name);
	if (!linux_readproc(name)) return linux_getnext();
	linux_proc.uid = dirstat.st_uid;
	linux_proc.gid = dirstat.st_gid;
	return &linux_proc;
}

struct and_procent *linux_getfrompid (int pid)
{
	char name [1024];
	struct stat dirstat;

	/* stat() /proc/<pid> directory to get uid/gid */
	snprintf(name, 1024, "/proc/%d", pid);
	stat(name,&dirstat);
	/* read the job's stat "file" to get command, nice level, etc */
	snprintf(name, 1024, "/proc/%d/stat", pid);
	linux_readproc(name);
	linux_proc.uid = dirstat.st_uid;
	linux_proc.gid = dirstat.st_gid;

	return &linux_proc;
}

struct and_procent *linux_getfirst ()
{
	if (linux_procdir) {
		rewinddir(linux_procdir);
	} else {
		linux_procdir = opendir("/proc");
		if (!linux_procdir) {
			and_printf(0,"cannot open /proc, aborting.\n");
			abort();
		}
	}
	return linux_getnext();
}

int main (int argc, char** argv)
{
	and_setprocreader(&linux_getfirst, &linux_getnext, &linux_getfrompid);
	return and_main(argc,argv);
}