/*
** ATOP - System & Process Monitor
**
** The program 'atop' offers the possibility to view the activity of
** the system on system-level as well as process-level.
**
** This source-file contains functions to manipulate with process-accounting
** features (switch it on/off and read the process-accounting records).
** ================================================================
** Author:      Gerlof Langeveld - AT Computing, Nijmegen, Holland
** E-mail:      gerlof@ATComputing.nl
** Date:        November 1996
** LINUX-port:  June 2000
**
** 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, 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.
**
** $Log: acctproc.c,v $
** Revision 1.26  2008/03/06 08:37:25  gerlof
** Register/show ppid of a process.
**
** Revision 1.25  2008/01/14 09:22:23  gerlof
** Support for environment variable ATOPACCT to specify the name of a
** particular process accouting file.
**
** Revision 1.24  2007/08/17 08:50:26  gerlof
** Verify if private accounting used before switching off accounting.
**
** Revision 1.23  2007/03/20 13:01:51  gerlof
** Introduction of variable supportflags.
**
** Revision 1.22  2007/02/13 09:14:49  gerlof
** New boolean introduced to indicate if accounting is active.
**
** Revision 1.21  2006/02/07 06:46:15  gerlof
** Removed swap-counter.
**
** Revision 1.20  2005/11/04 14:17:10  gerlof
** Improved recognition of certain version process accounting file.
**
** Revision 1.19  2005/10/31 12:44:58  gerlof
** Support account-record version 3 (used by Mandriva).
**
** Revision 1.18  2005/10/31 08:55:05  root
** *** empty log message ***
**
** Revision 1.17  2004/12/14 15:05:00  gerlof
** Implementation of patch-recognition for disk and network-statistics.
**
** Revision 1.16  2004/06/01 11:57:22  gerlof
** Consider other standard accounting-files, i.e. /var/account/pacct.
**
** Revision 1.15  2004/05/06 09:48:21  gerlof
** Ported to kernel-version 2.6.
**
** Revision 1.14  2003/07/07 09:26:15  gerlof
** Cleanup code (-Wall proof).
**
** Revision 1.13  2003/07/02 06:43:11  gerlof
** Modified include-file sys/acct.h to linux/acct.h to make it
** work on Alpha-based systems as well.
**
** Revision 1.12  2003/06/27 12:31:24  gerlof
** Adapt long to long long.
**
** Revision 1.11  2003/04/03 08:32:58  gerlof
** Cosmetic changes.
**
** Revision 1.10  2003/01/14 09:01:45  gerlof
** Small cosmetic changes.
**
** Revision 1.9  2002/10/03 11:12:03  gerlof
** Modify (effective) uid/gid to real uid/gid.
**
** Revision 1.8  2002/07/24 11:11:12  gerlof
** Redesigned to ease porting to other UNIX-platforms.
**
** Revision 1.7  2002/07/11 07:28:29  root
** Some additions related to secure accounting file handling
**
** Revision 1.6  2002/07/08 09:14:54  root
** Modified secure handling of accounting file
** (inspired by Tobias Rittweiler).
**
** Revision 1.5  2001/11/07 09:16:55  gerlof
** Allow users to run atop without process-accounting switched on.
**
** Revision 1.4  2001/10/16 06:15:52  gerlof
** Partly redesigned.
**
** Revision 1.3  2001/10/04 13:02:24  gerlof
** Redesign of the way to determine how many atop's are using process-accounting
** on basis of semaphores.
**
** Revision 1.2  2001/10/04 08:46:46  gerlof
** Improved verification of kernel-symbol addresses
**
** Revision 1.1  2001/10/02 10:38:35  gerlof
** Initial revision
**
*/

static const char rcsid[] = "$Id: acctproc.c,v 1.26 2008/03/06 08:37:25 gerlof Exp $";

#include <sys/types.h>
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/wait.h>

#include "atop.h"
#include "photoproc.h"
#include "acctproc.h"

#define	ACCTDIR		"/var/run/atop"
#define	ACCTFILE	"atop.acct"
#define	ACCTENV		"ATOPACCT"

static	char 	acctatop;	/* boolean: atop's own accounting busy ?  */
static	off_t	acctsize;	/* previous size of account file	  */
static	int	acctrecsz;	/* size of account record		  */
static	int	acctversion;	/* version of account record layout	  */
static	int   	acctfd = -1;	/* fd of account file       		  */

static count_t 	acctexp (comp_t  ct);
static count_t	acctexp2(comp2_t ct);
static int	acctvers(int);

struct pacctadm {
	char		*name;
	struct stat	stat;
} pacctadm[] = {
	{ "/var/log/account/pacct",	{0, }, },
	{ "/var/log/pacct",		{0, }, },
	{ "/var/account/pacct",		{0, }, }
};

/*
** Semaphore-handling
**
**  A semaphore-group with two semaphores is created
**
**     0 - Binary semaphore (mutex) to get access to active atop-counter
**
**     1 - Active atop-counter (inverted).
**         This semaphore is initialized at some high value and is
**         decremented by every atop-incarnation which uses the private
**         accounting-file and incremented as soon as such atop stops again.
**         If an atop-incarnation stops and it appears to be the last one
**         using the private accounting-file, accounting is stopped
**         and the file removed
**	   (Yes, I know: it's not proper usage of the semaphore-principle).
*/ 
#define	SEMAKEY		3121959
#define	SEMTOTAL	100

struct sembuf	semclaim = {0, -1, SEM_UNDO},
		semrelse = {0, +1, SEM_UNDO},
		semdecre = {1, -1, SEM_UNDO},
		semincre = {1, +1, SEM_UNDO};

/*
** switch on the process-accounting mechanism
*/
int
acctswon(void)
{
	int			i, j, semid;
	static ushort 		vals[] = {1, SEMTOTAL};
	union {ushort *array;}	arg = {vals};
	struct stat		statbuf;
	char			*ep;

	/*
	** when a particular environment variable is present, atop should
	** use a specific accounting-file (as defined by the environment
	** variable) or should use no process accounting at all (when
	** contents of environment variable is empty)
	*/
	if ( (ep = getenv(ACCTENV)) )
	{
		/*
		** environment variable exists
		*/
		if (*ep)
		{
			/*
			** open active account file with the specified name
			*/
			seteuid( getuid() );	/* drop setuid-root privs */

			if ( (acctfd = open(ep, O_RDONLY) ) == -1)
			{
				perror("open account-file");
				fprintf(stderr,
			                "warning: no process exit detection\n");
				sleep(3);
				return 0;
			}

			if ( !acctvers(acctfd) )
			{
				fprintf(stderr,
               				"warning: no process exit detection\n");
				sleep(3);
				(void) close(acctfd);
				return 0;
			}

			supportflags |= ACCTACTIVE;
			return 1;
		}
		else
		{
			/*
			** no contents
			*/
			return 0;
		}
	}

	/*
	** check if process-accounting is already switched on 
	** for one of the standard accounting-files; in that case we
	** open this file and get our info from here ....
	*/
	for (i=0, j=0; i < sizeof pacctadm/sizeof pacctadm[0]; i++)
	{
		if ( stat(pacctadm[i].name, &pacctadm[i].stat) == 0)
			j++;
	}

	if (j)
	{
		/*
		** at least one file is present; check if it is really in use
		** at this moment for accounting by forking a child-process
		** which immediately finishes to force a new accounting-record
		*/
		if ( fork() == 0 )
			exit(0);	/* let the child finish */

		(void) wait((int *) 0); /* let the parent wait  */

		for (i=0; i < sizeof pacctadm/sizeof pacctadm[0]; i++)
		{
			if ( stat(pacctadm[i].name, &statbuf) == 0)
			{
				/*
				** accounting-file has grown?
				*/
				if (statbuf.st_size > pacctadm[i].stat.st_size)
				{
					/*
					** open active account file
					*/
					if ( (acctfd = open(pacctadm[i].name,
							    O_RDONLY) ) == -1)
					{
						perror("open account-file");
						fprintf(stderr,
					                "warning: no process "
							"exit detection\n");
						sleep(3);
						return 0;
					}

					if ( !acctvers(acctfd) )
					{
						fprintf(stderr,
	                				"warning: no process "
						        "exit detection\n");
						sleep(3);
						(void) close(acctfd);
						return 0;
					}

					supportflags |= ACCTACTIVE;
					return 1;
				}
			}
		}
	}

	/*
	** process-accounting is not yet switched on in a standard way;
	** check if another atop has switched on accounting already
	**
	** first try to create a semaphore exclusively; if this succeeds,
	** this is the first atop-incarnation since boot and the semaphore
	** should be initialized
	*/
	if ( (semid = semget(SEMAKEY, 2, 0666|IPC_CREAT|IPC_EXCL)) >= 0)
		(void) semctl(semid, 0, SETALL, arg);
	else
		semid = semget(SEMAKEY, 0, 0);

	/*
	** check if we got access to the semaphore-group
	*/
	if (semid == -1)
	{
		perror("open semaphore-group");
		fprintf(stderr, "warning: no process exit detection\n");
		sleep(3);
		return 0;
	}

	/*
	** the semaphore-group is opened now; claim exclusive rights
	*/
	(void) semop(semid, &semclaim, 1);

   	/*
   	** are we the first to use the accounting-mechanism ?
   	*/
	if (semctl(semid, 1, GETVAL, 0) == SEMTOTAL)
	{
		/*
		** create a new separate directory below /var/run
		** for the accounting file;
		** if this directory exists (e.g. previous atop-run killed)
		** it will be cleaned and newly created
		*/
		if ( mkdir(ACCTDIR, 0700) == -1)
		{
			if (errno == EEXIST)
			{
				(void) acct(0);
				(void) unlink(ACCTDIR "/" ACCTFILE);
				(void) rmdir(ACCTDIR);
			}

			if ( mkdir(ACCTDIR, 0700) == -1)
			{
				/*
				** persistent failure
				*/
				fprintf(stderr,
					"warning: no process exit detection "
				        "(can not create directory %s)\n",
						ACCTDIR);

				(void) semop(semid, &semrelse, 1);
				sleep(3);
				return 0;
			}
		}

		/*
		** create accounting file in new directory
		*/
		(void) close( creat(ACCTDIR "/" ACCTFILE, 0600) );

		/*
		** switch on accounting
		*/
		if ( acct(ACCTDIR "/" ACCTFILE) < 0)
		{
			perror("activate process accounting");
			fprintf(stderr, "warning: no process exit detection");

			if (errno == EPERM)
				fprintf(stderr, " (not superuser)!\n");
			else
				fprintf(stderr, "!\n");

			(void) unlink(ACCTDIR "/" ACCTFILE);
			(void) rmdir(ACCTDIR);
			(void) semop(semid, &semrelse, 1);

			sleep(3);
			return 0;
		}
	}

	/*
	** accounting is switched on now;
	** open accounting-file
	*/
	if ( (acctfd = open(ACCTDIR "/" ACCTFILE, O_RDONLY) ) < 0)
	{
		perror("open account-file");
		fprintf(stderr, "warning: no process exit detection!\n");

		(void) acct(0);
		(void) unlink(ACCTDIR "/" ACCTFILE);
		(void) rmdir(ACCTDIR);

		(void) semop(semid, &semrelse, 1);

		sleep(3);
		return 0;
	}

	/*
	** accounting successfully switched on
	*/
	(void) semop(semid, &semdecre, 1);
	(void) semop(semid, &semrelse, 1);

	acctatop = 1;

	/*
	** determine version of accounting-record
	*/ 
	(void) fstat(acctfd, &statbuf);

	if (statbuf.st_size == 0)	/* no acct record written yet */
	{
		/*
		** let's write one record
		*/
		if ( fork() == 0 )
			exit(0);	/* let the child finish */

		(void) wait((int *) 0); /* let the parent wait  */
	}

	acctvers(acctfd);

	supportflags |= ACCTACTIVE;
	return 1;
}

/*
** determine the version of the accounting-record layout/length
** and reposition the seek-pointer to the end of the accounting file
*/
static int
acctvers(int fd)
{
	struct acct 	tmprec;

	/*
	** read first record from accouting file to verify
	** the second byte (always contains version number)
	*/
	if ( read(fd, &tmprec, sizeof tmprec) < sizeof tmprec)
		return 0;

	switch (tmprec.ac_version)
	{
	   case 3:
	   	acctrecsz     = sizeof(struct acct_v3);
		acctversion   = 3;
		break;

	   case 6:
	   	acctrecsz     = sizeof(struct acct_atop);
		acctversion   = 6;
		supportflags |= PATCHACCT;  
		break;

	   default:
	   	acctrecsz     = sizeof(struct acct);
		acctversion   = 2;
	}

	/*
	** accounting successfully switched on
	*/
	acctsize = acctprocnt() * acctrecsz;

	/*
	** reposition to actual file-size
	*/
	(void)lseek(fd, acctsize, SEEK_SET);

	return 1;
}

/*
** switch off the process-accounting mechanism
*/
void
acctswoff(void)
{
	int		semid;
	struct stat	before, after;

	/*
	** if accounting not supported, skip call
	*/
	if (acctfd == -1)
		return;

	/*
	** our private accounting-file in use?
	*/
	if (acctatop)
	{
		acctatop = 0;

		/*
		** claim the semaphore to get exclusive rights for
		** the accounting-manipulation
		*/
		semid = semget(SEMAKEY, 0, 0);

		(void) semop(semid, &semclaim, 1);
		(void) semop(semid, &semincre, 1);

		/*
		** check if we were the last user of accounting
		*/
		if (semctl(semid, 1, GETVAL, 0) == SEMTOTAL)
		{
			/*
			** switch off private accounting
			**
			** verify if private accounting is still in use to
			** avoid that we switch off process accounting that
			** has been activated manually in the meantime
			*/
			(void) fstat(acctfd, &before);

			if ( fork() == 0 )	/* create a child and   */
				exit(0);	/* let the child finish */

			(void) wait((int *) 0); /* let the parent wait  */

			(void) fstat(acctfd, &after);

			if (after.st_size > before.st_size)
			{
				/*
				** remove the directory and file
				*/
				seteuid(0);	/* get root privs again */

				(void) acct(0);
				(void) unlink(ACCTDIR "/" ACCTFILE);
				(void) rmdir(ACCTDIR);
			}
		}

		(void) semop(semid, &semrelse, 1);
	}

	/*
	** anyhow close the accounting-file again
	*/
	(void) close(acctfd);	/* close account file again */

	supportflags &= ~ACCTACTIVE;
}

/*
** get the number of exited processes written
** in the process-account file since the previous sample
*/
int
acctprocnt(void)
{
	struct stat 		statacc;

	/*
	** if accounting not supported, skip call
	*/
	if (acctfd == -1)
		return 0;

	/*
	** determine how many processes exited last interval
	*/
	(void) fstat(acctfd, &statacc);

	if (acctsize > statacc.st_size)	/* somebody did reset accounting? */
	{
		/*
		** reposition to start of file
		*/
		lseek(acctfd, 0, SEEK_SET);
		acctsize = 0;
	}

	return (statacc.st_size - acctsize) / acctrecsz;
}

/*
** read process-records from the account-file,
** which are written since the previous cycle
*/
int
acctphotoproc(struct pstat *accproc, int nrprocs)
{
	register int 		nrexit;
	register struct pstat 	*api;
	struct acct 		acctrec;
	struct acct_v3 		acctrec_v3;
	struct acct_atop	acctrec_atop;

	/*
	** if accounting not supported, skip call
	*/
	if (acctfd == -1)
		return 0;

	/*
	** check all exited processes in accounting file
	*/
	for  (nrexit=0, api=accproc; nrexit < nrprocs; nrexit++, api++)
	{
		switch (acctversion)
		{
		   case 2:
			if ( read(acctfd, &acctrec, acctrecsz) < acctrecsz )
				break;	/* unexpected end of account file */

			/*
			** fill process info from accounting-record
			*/
			api->gen.state  = 'E';
			api->gen.nthr   = 1;
			api->gen.ppid   = 0;
			api->gen.excode = acctrec.ac_exitcode;
			api->gen.ruid   = acctrec.ac_uid16;
			api->gen.rgid   = acctrec.ac_gid16;
			api->gen.btime  = acctrec.ac_btime;
			api->cpu.stime  = acctexp(acctrec.ac_stime);
			api->cpu.utime  = acctexp(acctrec.ac_utime);
			api->mem.minflt = acctexp(acctrec.ac_minflt);
			api->mem.majflt = acctexp(acctrec.ac_majflt);
			api->dsk.rio    = acctexp(acctrec.ac_rw);

			strcpy(api->gen.name, acctrec.ac_comm);
			break;

		   case 3:
			if ( read(acctfd, &acctrec_v3, acctrecsz) < acctrecsz )
				break;	/* unexpected end of account file */

			/*
			** fill process info from accounting-record
			*/
			api->gen.state  = 'E';
			api->gen.pid    = acctrec_v3.ac_pid;
			api->gen.ppid   = acctrec_v3.ac_ppid;
			api->gen.nthr   = 1;
			api->gen.excode = acctrec_v3.ac_exitcode;
			api->gen.ruid   = acctrec_v3.ac_uid;
			api->gen.rgid   = acctrec_v3.ac_gid;
			api->gen.btime  = acctrec_v3.ac_btime;
			api->cpu.stime  = acctexp(acctrec_v3.ac_stime);
			api->cpu.utime  = acctexp(acctrec_v3.ac_utime);
			api->mem.minflt = acctexp(acctrec_v3.ac_minflt);
			api->mem.majflt = acctexp(acctrec_v3.ac_majflt);
			api->dsk.rio    = acctexp(acctrec_v3.ac_rw);

			strcpy(api->gen.name, acctrec_v3.ac_comm);
			break;

		   case 6:
			if ( read(acctfd, &acctrec_atop, acctrecsz) <acctrecsz)
				break;	/* unexpected end of account file */

			/*
			** fill process info from accounting-record
			*/
			api->gen.state  = 'E';
			api->gen.pid    = acctrec_atop.ac_pid;
			api->gen.ppid   = acctrec_atop.ac_ppid;
			api->gen.nthr   = 1;
			api->gen.excode = acctrec_atop.ac_exitcode;
			api->gen.ruid   = acctrec_atop.ac_uid;
			api->gen.rgid   = acctrec_atop.ac_gid;
			api->gen.btime  = acctrec_atop.ac_btime;
			api->cpu.stime  = acctexp (acctrec_atop.ac_stime);
			api->cpu.utime  = acctexp (acctrec_atop.ac_utime);
			api->mem.minflt = acctexp (acctrec_atop.ac_minflt);
			api->mem.majflt = acctexp (acctrec_atop.ac_majflt);
			api->mem.vmem   = acctexp (acctrec_atop.ac_mem);
			api->mem.rmem   = acctexp (acctrec_atop.ac_rss);
			api->dsk.rio    = acctexp (acctrec_atop.ac_bread);
			api->dsk.wio    = acctexp (acctrec_atop.ac_bwrite);
			api->dsk.rsz    = acctexp2(acctrec_atop.ac_dskrsz);
			api->dsk.wsz    = acctexp2(acctrec_atop.ac_dskwsz);
			api->net.tcpsnd = acctexp (acctrec_atop.ac_tcpsnd);
			api->net.tcprcv = acctexp (acctrec_atop.ac_tcprcv);
			api->net.tcpssz = acctexp2(acctrec_atop.ac_tcpssz);
			api->net.tcprsz = acctexp2(acctrec_atop.ac_tcprsz);
			api->net.udpsnd = acctexp (acctrec_atop.ac_udpsnd);
			api->net.udprcv = acctexp (acctrec_atop.ac_udprcv);
			api->net.udpssz = acctexp2(acctrec_atop.ac_udpssz);
			api->net.udprsz = acctexp2(acctrec_atop.ac_udprsz);
			api->net.rawsnd = acctexp (acctrec_atop.ac_rawsnd);
			api->net.rawrcv = acctexp (acctrec_atop.ac_rawrcv);

			strcpy(api->gen.name, acctrec_atop.ac_comm);
		}
	}

	acctsize += nrexit * acctrecsz;

	return nrexit;
}

/*
** expand the special compression-methods
*/
static count_t
acctexp(comp_t ct)
{
        count_t	exp;
        count_t val;

        exp = (ct >> 13) & 0x7;		/* obtain  3 bits base-8 exponent */
        val =  ct & 0x1fff;		/* obtain 13 bits mantissa        */

        while (exp-- > 0)
                val <<= 3;

        return val;
}

static count_t
acctexp2(comp2_t ct)
{
	count_t exp;
	count_t val;

	exp = (ct >> 20) & 0xfff;         /* obtain  5 bits base-2 exponent */
	val =  ct & 0xfffff;              /* obtain 20 bits mantissa        */

	while (exp-- > 0)
		val <<= 2;

	return val;
}