miscutils/crond.c

/*
 * crond -d[#] -c <crondir> -f -b
 *
 * run as root, but NOT setuid root
 *
 * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com)
 * May be distributed under the GNU General Public License
 *
 * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002 to be used in busybox
 */

#define VERSION "2.3.2"

#undef FEATURE_DEBUG_OPT


#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <dirent.h>
#include <fcntl.h>
#include <unistd.h>
#include <syslog.h>
#include <signal.h>
#include <getopt.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/resource.h>

#include "busybox.h"

#define arysize(ary)    (sizeof(ary)/sizeof((ary)[0]))

#ifndef CRONTABS
#define CRONTABS        "/var/spool/cron/crontabs"
#endif
#ifndef TMPDIR
#define TMPDIR          "/var/spool/cron"
#endif
#ifndef SENDMAIL
#define SENDMAIL        "/usr/sbin/sendmail"
#endif
#ifndef SENDMAIL_ARGS
#define SENDMAIL_ARGS   "-ti", "oem"
#endif
#ifndef CRONUPDATE
#define CRONUPDATE      "cron.update"
#endif
#ifndef MAXLINES
#define MAXLINES        256             /* max lines in non-root crontabs */
#endif

static const char def_sh[] = "/bin/sh";


typedef struct CronFile {
    struct CronFile *cf_Next;
    struct CronLine *cf_LineBase;
    char        *cf_User;       /* username                     */
    int         cf_Ready;       /* bool: one or more jobs ready */
    int         cf_Running;     /* bool: one or more jobs running */
    int         cf_Deleted;     /* marked for deletion, ignore  */
} CronFile;

typedef struct CronLine {
    struct CronLine *cl_Next;
    char        *cl_Shell;      /* shell command                        */
    pid_t       cl_Pid;         /* running pid, 0, or armed (-1)        */
    int         cl_MailFlag;    /* running pid is for mail              */
    int         cl_MailPos;     /* 'empty file' size                    */
    char        cl_Mins[60];    /* 0-59                                 */
    char        cl_Hrs[24];     /* 0-23                                 */
    char        cl_Days[32];    /* 1-31                                 */
    char        cl_Mons[12];    /* 0-11                                 */
    char        cl_Dow[7];      /* 0-6, beginning sunday                */
} CronLine;

#define RUN_RANOUT      1
#define RUN_RUNNING     2
#define RUN_FAILED      3

#define DaemonUid 0

#ifdef FEATURE_DEBUG_OPT
static short DebugOpt;
#endif

static short LogLevel = 8;
static const char  *LogFile;
static const char  *CDir = CRONTABS;

static void startlogger(void);

static void CheckUpdates(void);
static void SynchronizeDir(void);
static int TestJobs(time_t t1, time_t t2);
static void RunJobs(void);
static int CheckJobs(void);

static void RunJob(const char *user, CronLine *line);
#ifdef CONFIG_FEATURE_CROND_CALL_SENDMAIL
static void EndJob(const char *user, CronLine *line);
#else
#define EndJob(user, line)  line->cl_Pid = 0
#endif

static void DeleteFile(const char *userName);

static CronFile *FileBase;


static void
log(const char *ctl, ...)
{
    va_list va;
    int level = (int)(ctl[0] & 0xf);
    int type = level == 20 ?
		    LOG_ERR : ((ctl[0] & 0100) ? LOG_WARNING : LOG_NOTICE);


    va_start(va, ctl);
    if (level >= LogLevel) {

#ifdef FEATURE_DEBUG_OPT
	if (DebugOpt) vfprintf(stderr, ctl, va);
	else
#endif
	    if (LogFile == 0) vsyslog(type, ctl, va);
	    else {
		 int  logfd;

		 if ((logfd = open(LogFile, O_WRONLY|O_CREAT|O_APPEND, 600)) >= 0) {
		    vdprintf(logfd, ctl, va);
		    close(logfd);
#ifdef FEATURE_DEBUG_OPT
		 } else {
		    bb_perror_msg("Can't open log file");
#endif
		}
	    }
    }
    va_end(va);
    if(ctl[0] & 0200)
	exit(20);
}

int
crond_main(int ac, char **av)
{
    unsigned long opt;
    char *lopt, *Lopt, *copt;
#ifdef FEATURE_DEBUG_OPT
    char *dopt;
    bb_opt_complementaly = "f-b:b-f:S-L:L-S:d-l";
#else
    bb_opt_complementaly = "f-b:b-f:S-L:L-S";
#endif

    opterr = 0;         /* disable getopt 'errors' message.*/
    opt = bb_getopt_ulflags(ac, av, "l:L:fbSc:"
#ifdef FEATURE_DEBUG_OPT
				"d:"
#endif
	    , &lopt, &Lopt, &copt
#ifdef FEATURE_DEBUG_OPT
	    , &dopt
#endif
	    );
    if(opt & 1)
	LogLevel = atoi(lopt);
    if(opt & 2)
	if (*Lopt != 0) LogFile = Lopt;
    if(opt & 32) {
	if (*copt != 0) CDir = copt;
	}
#ifdef FEATURE_DEBUG_OPT
    if(opt & 64) {
	DebugOpt = atoi(dopt);
	LogLevel = 0;
    }
#endif

    /*
     * change directory
     */

    if (chdir(CDir) != 0)
	bb_perror_msg_and_die("%s", CDir);

    signal(SIGHUP,SIG_IGN);   /* hmm.. but, if kill -HUP original
				 * version - his died. ;(
				 */
    /*
     * close stdin and stdout, stderr.
     * close unused descriptors -  don't need.
     * optional detach from controlling terminal
     */

    if (!(opt & 4)) {
	if(daemon(1, 0) < 0) {
		bb_perror_msg_and_die("daemon");
#if defined(__uClinux__)
	} else {
	    /* reexec for vfork() do continue parent */
	    vfork_daemon_rexec(ac, av, "-f");
	}
#endif /* uClinux */
    }

    (void)startlogger();                /* need if syslog mode selected */

    /*
     * main loop - synchronize to 1 second after the minute, minimum sleep
     *             of 1 second.
     */

    log("\011%s " VERSION " dillon, started, log level %d\n", bb_applet_name,
						LogLevel);

    SynchronizeDir();

    {
	time_t t1 = time(NULL);
	time_t t2;
	long dt;
	short rescan = 60;
	short sleep_time = 60;

	for (;;) {
	    sleep((sleep_time + 1) - (short)(time(NULL) % sleep_time));

	    t2 = time(NULL);
	    dt = t2 - t1;

	    /*
	     * The file 'cron.update' is checked to determine new cron
	     * jobs.  The directory is rescanned once an hour to deal
	     * with any screwups.
	     *
	     * check for disparity.  Disparities over an hour either way
	     * result in resynchronization.  A reverse-indexed disparity
	     * less then an hour causes us to effectively sleep until we
	     * match the original time (i.e. no re-execution of jobs that
	     * have just been run).  A forward-indexed disparity less then
	     * an hour causes intermediate jobs to be run, but only once
	     * in the worst case.
	     *
	     * when running jobs, the inequality used is greater but not
	     * equal to t1, and less then or equal to t2.
	     */

	    if (--rescan == 0) {
		rescan = 60;
		SynchronizeDir();
	    }
	    CheckUpdates();
#ifdef FEATURE_DEBUG_OPT
	    if (DebugOpt)
		log("\005Wakeup dt=%d\n", dt);
#endif
	    if (dt < -60*60 || dt > 60*60) {
		t1 = t2;
		log("\111time disparity of %d minutes detected\n", dt / 60);
	    } else if (dt > 0) {
		TestJobs(t1, t2);
		RunJobs();
		sleep(5);
		if (CheckJobs() > 0)
		   sleep_time = 10;
		else
		   sleep_time = 60;
		t1 = t2;
	    }
	}
    }
    /* not reached */
}


#if defined(FEATURE_DEBUG_OPT) || defined(CONFIG_FEATURE_CROND_CALL_SENDMAIL)
/*
    write to temp file..
*/
static void
fdprintf(int fd, const char *ctl, ...)
{
    va_list va;

    va_start(va, ctl);
    vdprintf(fd, ctl, va);
    va_end(va);
}
#endif


static int
ChangeUser(const char *user)
{
    struct passwd *pas;

    /*
     * Obtain password entry and change privilages
     */

    if ((pas = getpwnam(user)) == 0) {
	log("\011failed to get uid for %s", user);
	return(-1);
    }
    setenv("USER", pas->pw_name, 1);
    setenv("HOME", pas->pw_dir, 1);
    setenv("SHELL", def_sh, 1);

    /*
     * Change running state to the user in question
     */

    if (initgroups(user, pas->pw_gid) < 0) {
	log("\011initgroups failed: %s %m", user);
	return(-1);
    }
    /* drop all priviledges */
    if (setgid(pas->pw_gid) < 0) {
	log("\011setgid failed: %s %d", user, pas->pw_gid);
	return(-1);
    }
    if (setuid(pas->pw_uid) < 0) {
	log("\011setuid failed: %s %d", user, pas->pw_uid);
	return(-1);
    }
	if (chdir(pas->pw_dir) < 0) {
	log("\011chdir failed: %s: %m", pas->pw_dir);
	    if (chdir(TMPDIR) < 0) {
	    log("\011chdir failed: %s: %m", TMPDIR);
		return(-1);
	    }
	}
    return(pas->pw_uid);
}

static void
startlogger(void)
{
    if (LogFile == 0)
	openlog(bb_applet_name, LOG_CONS|LOG_PID, LOG_CRON);
#ifdef FEATURE_DEBUG_OPT
    else { /* test logfile */
    int  logfd;

	if ((logfd = open(LogFile, O_WRONLY|O_CREAT|O_APPEND, 600)) >= 0)
	   close(logfd);
	else
	   bb_perror_msg("Failed to open log file '%s' reason", LogFile);
    }
#endif
}


static const char * const DowAry[] = {
    "sun",
    "mon",
    "tue",
    "wed",
    "thu",
    "fri",
    "sat",

    "Sun",
    "Mon",
    "Tue",
    "Wed",
    "Thu",
    "Fri",
    "Sat",
    NULL
};

static const char * const MonAry[] = {
    "jan",
    "feb",
    "mar",
    "apr",
    "may",
    "jun",
    "jul",
    "aug",
    "sep",
    "oct",
    "nov",
    "dec",

    "Jan",
    "Feb",
    "Mar",
    "Apr",
    "May",
    "Jun",
    "Jul",
    "Aug",
    "Sep",
    "Oct",
    "Nov",
    "Dec",
    NULL
};

static char *
ParseField(char *user, char *ary, int modvalue, int off,
				const char * const *names, char *ptr)
{
    char *base = ptr;
    int n1 = -1;
    int n2 = -1;

    if (base == NULL)
	return(NULL);

    while (*ptr != ' ' && *ptr != '\t' && *ptr != '\n') {
	int skip = 0;

	/*
	 * Handle numeric digit or symbol or '*'
	 */

	if (*ptr == '*') {
	    n1 = 0;                     /* everything will be filled */
	    n2 = modvalue - 1;
	    skip = 1;
	    ++ptr;
	} else if (*ptr >= '0' && *ptr <= '9') {
	    if (n1 < 0)
		n1 = strtol(ptr, &ptr, 10) + off;
	    else
		n2 = strtol(ptr, &ptr, 10) + off;
	    skip = 1;
	} else if (names) {
	    int i;

	    for (i = 0; names[i]; ++i) {
		if (strncmp(ptr, names[i], strlen(names[i])) == 0) {
		    break;
		}
	    }
	    if (names[i]) {
		ptr += strlen(names[i]);
		if (n1 < 0)
		    n1 = i;
		else
		    n2 = i;
		skip = 1;
	    }
	}

	/*
	 * handle optional range '-'
	 */

	if (skip == 0) {
	    log("\111failed user %s parsing %s\n", user, base);
	    return(NULL);
	}
	if (*ptr == '-' && n2 < 0) {
	    ++ptr;
	    continue;
	}

	/*
	 * collapse single-value ranges, handle skipmark, and fill
	 * in the character array appropriately.
	 */

	if (n2 < 0)
	    n2 = n1;

	if (*ptr == '/')
	    skip = strtol(ptr + 1, &ptr, 10);

	/*
	 * fill array, using a failsafe is the easiest way to prevent
	 * an endless loop
	 */

	{
	    int s0 = 1;
	    int failsafe = 1024;

	    --n1;
	    do {
		n1 = (n1 + 1) % modvalue;

		if (--s0 == 0) {
		    ary[n1 % modvalue] = 1;
		    s0 = skip;
		}
	    } while (n1 != n2 && --failsafe);

	    if (failsafe == 0) {
		log("\111failed user %s parsing %s\n", user, base);
		return(NULL);
	    }
	}
	if (*ptr != ',')
	    break;
	++ptr;
	n1 = -1;
	n2 = -1;
    }

    if (*ptr != ' ' && *ptr != '\t' && *ptr != '\n') {
	log("\111failed user %s parsing %s\n", user, base);
	return(NULL);
    }

    while (*ptr == ' ' || *ptr == '\t' || *ptr == '\n')
	++ptr;

#ifdef FEATURE_DEBUG_OPT
    if (DebugOpt) {
	int i;

	for (i = 0; i < modvalue; ++i)
	    log("\005%d", ary[i]);
	log("\005\n");
    }
#endif

    return(ptr);
}

static void
FixDayDow(CronLine *line)
{
    short i;
    short weekUsed = 0;
    short daysUsed = 0;

    for (i = 0; i < arysize(line->cl_Dow); ++i) {
	if (line->cl_Dow[i] == 0) {
	    weekUsed = 1;
	    break;
	}
    }
    for (i = 0; i < arysize(line->cl_Days); ++i) {
	if (line->cl_Days[i] == 0) {
	    daysUsed = 1;
	    break;
	}
    }
    if (weekUsed && !daysUsed) {
	memset(line->cl_Days, 0, sizeof(line->cl_Days));
    }
    if (daysUsed && !weekUsed) {
	memset(line->cl_Dow, 0, sizeof(line->cl_Dow));
    }
}



static void
SynchronizeFile(const char *fileName)
{
    int maxEntries = MAXLINES;
    int maxLines;
    char buf[1024];

    if (strcmp(fileName, "root") == 0)
	maxEntries = 65535;
    maxLines = maxEntries * 10;

    if (fileName) {
	FILE *fi;

	DeleteFile(fileName);

	if ((fi = fopen(fileName, "r")) != NULL) {
	    struct stat sbuf;

	    if (fstat(fileno(fi), &sbuf) == 0 && sbuf.st_uid == DaemonUid) {
		CronFile *file = calloc(1, sizeof(CronFile));
		CronLine **pline;

		file->cf_User = strdup(fileName);
		pline = &file->cf_LineBase;

		while (fgets(buf, sizeof(buf), fi) != NULL && --maxLines) {
		    CronLine line;
		    char *ptr;

		    if (buf[0])
			buf[strlen(buf)-1] = 0;

		    if (buf[0] == 0 || buf[0] == '#' || buf[0] == ' ' || buf[0] == '\t')
			continue;

		    if (--maxEntries == 0)
			break;

		    memset(&line, 0, sizeof(line));

#ifdef FEATURE_DEBUG_OPT
		    if (DebugOpt)
			log("\111User %s Entry %s\n", fileName, buf);
#endif

		    /*
		     * parse date ranges
		     */

		    ptr = ParseField(file->cf_User, line.cl_Mins, 60, 0, NULL, buf);
		    ptr = ParseField(file->cf_User, line.cl_Hrs,  24, 0, NULL, ptr);
		    ptr = ParseField(file->cf_User, line.cl_Days, 32, 0, NULL, ptr);
		    ptr = ParseField(file->cf_User, line.cl_Mons, 12, -1, MonAry, ptr);
		    ptr = ParseField(file->cf_User, line.cl_Dow, 7, 0, DowAry, ptr);

		    /*
		     * check failure
		     */

		    if (ptr == NULL)
			continue;

		    /*
		     * fix days and dow - if one is not * and the other
		     * is *, the other is set to 0, and vise-versa
		     */

		    FixDayDow(&line);

		    *pline = calloc(1, sizeof(CronLine));
		    **pline = line;

		    /*
		     * copy command
		     */

		    (*pline)->cl_Shell = strdup(ptr);

#ifdef FEATURE_DEBUG_OPT
		    if (DebugOpt) {
			log("\111    Command %s\n", ptr);
		    }
#endif

		    pline = &((*pline)->cl_Next);
		}
		*pline = NULL;

		file->cf_Next = FileBase;
		FileBase = file;

		if (maxLines == 0 || maxEntries == 0)
		    log("\111Maximum number of lines reached for user %s\n", fileName);
	    }
	    fclose(fi);
	}
    }
}

static void
CheckUpdates(void)
{
    FILE *fi;
    char buf[256];

    if ((fi = fopen(CRONUPDATE, "r")) != NULL) {
	remove(CRONUPDATE);
	while (fgets(buf, sizeof(buf), fi) != NULL) {
	    SynchronizeFile(strtok(buf, " \t\r\n"));
	}
	fclose(fi);
    }
}

static void
SynchronizeDir(void)
{
    /*
     * Attempt to delete the database.
     */

    for (;;) {
	CronFile *file;

	for (file = FileBase; file && file->cf_Deleted; file = file->cf_Next)
	    ;
	if (file == NULL)
	    break;
	DeleteFile(file->cf_User);
    }

    /*
     * Remove cron update file
     *
     * Re-chdir, in case directory was renamed & deleted, or otherwise
     * screwed up.
     *
     * scan directory and add associated users
     */

    remove(CRONUPDATE);
    if (chdir(CDir) < 0) {
	log("\311unable to find %s\n", CDir);
    }
    {
	DIR *dir;
	struct dirent *den;

	if ((dir = opendir("."))) {
	    while ((den = readdir(dir))) {
		if (strchr(den->d_name, '.') != NULL)
		    continue;
		if (getpwnam(den->d_name))
		    SynchronizeFile(den->d_name);
		else
		    log("\007ignoring %s\n", den->d_name);
	    }
	    closedir(dir);
	} else {
	    log("\311Unable to open current dir!\n");
	}
    }
}


/*
 *  DeleteFile() - delete user database
 *
 *  Note: multiple entries for same user may exist if we were unable to
 *  completely delete a database due to running processes.
 */

static void
DeleteFile(const char *userName)
{
    CronFile **pfile = &FileBase;
    CronFile *file;

    while ((file = *pfile) != NULL) {
	if (strcmp(userName, file->cf_User) == 0) {
	    CronLine **pline = &file->cf_LineBase;
	    CronLine *line;

	    file->cf_Running = 0;
	    file->cf_Deleted = 1;

	    while ((line = *pline) != NULL) {
		if (line->cl_Pid > 0) {
		    file->cf_Running = 1;
		    pline = &line->cl_Next;
		} else {
		    *pline = line->cl_Next;
		    free(line->cl_Shell);
		    free(line);
		}
	    }
	    if (file->cf_Running == 0) {
		*pfile = file->cf_Next;
		free(file->cf_User);
		free(file);
	    } else {
		pfile = &file->cf_Next;
	    }
	} else {
	    pfile = &file->cf_Next;
	}
    }
}

/*
 * TestJobs()
 *
 * determine which jobs need to be run.  Under normal conditions, the
 * period is about a minute (one scan).  Worst case it will be one
 * hour (60 scans).
 */

static int
TestJobs(time_t t1, time_t t2)
{
    short nJobs = 0;
    time_t t;

    /*
     * Find jobs > t1 and <= t2
     */

    for (t = t1 - t1 % 60; t <= t2; t += 60) {
	if (t > t1) {
	    struct tm *tp = localtime(&t);
	    CronFile *file;
	    CronLine *line;

	    for (file = FileBase; file; file = file->cf_Next) {
#ifdef FEATURE_DEBUG_OPT
		if (DebugOpt)
		    log("\005FILE %s:\n", file->cf_User);
#endif
		if (file->cf_Deleted)
		    continue;
		for (line = file->cf_LineBase; line; line = line->cl_Next) {
#ifdef FEATURE_DEBUG_OPT
		    if (DebugOpt)
			log("\005    LINE %s\n", line->cl_Shell);
#endif
		    if (line->cl_Mins[tp->tm_min] &&
			line->cl_Hrs[tp->tm_hour] &&
			(line->cl_Days[tp->tm_mday] || line->cl_Dow[tp->tm_wday]) &&
			line->cl_Mons[tp->tm_mon]
		    ) {
#ifdef FEATURE_DEBUG_OPT
			if (DebugOpt)
			    log("\005    JobToDo: %d %s\n", line->cl_Pid, line->cl_Shell);
#endif
			if (line->cl_Pid > 0) {
			    log("\010    process already running: %s %s\n",
				file->cf_User,
				line->cl_Shell
			    );
			} else if (line->cl_Pid == 0) {
			    line->cl_Pid = -1;
			    file->cf_Ready = 1;
			    ++nJobs;
			}
		    }
		}
	    }
	}
    }
    return(nJobs);
}

static void
RunJobs(void)
{
    CronFile *file;
    CronLine *line;

    for (file = FileBase; file; file = file->cf_Next) {
	if (file->cf_Ready) {
	    file->cf_Ready = 0;

	    for (line = file->cf_LineBase; line; line = line->cl_Next) {
		if (line->cl_Pid < 0) {

		    RunJob(file->cf_User, line);

		    log("\010USER %s pid %3d cmd %s\n",
			file->cf_User,
			line->cl_Pid,
			line->cl_Shell
		    );
		    if (line->cl_Pid < 0)
			file->cf_Ready = 1;
		    else if (line->cl_Pid > 0)
			file->cf_Running = 1;
		}
	    }
	}
    }
}

/*
 * CheckJobs() - check for job completion
 *
 * Check for job completion, return number of jobs still running after
 * all done.
 */

static int
CheckJobs(void)
{
    CronFile *file;
    CronLine *line;
    int nStillRunning = 0;

    for (file = FileBase; file; file = file->cf_Next) {
	if (file->cf_Running) {
	    file->cf_Running = 0;

	    for (line = file->cf_LineBase; line; line = line->cl_Next) {
		if (line->cl_Pid > 0) {
		    int status;
		    int r = wait4(line->cl_Pid, &status, WNOHANG, NULL);

		    if (r < 0 || r == line->cl_Pid) {
			EndJob(file->cf_User, line);
			if (line->cl_Pid)
			    file->cf_Running = 1;
		    } else if (r == 0) {
			file->cf_Running = 1;
		    }
		}
	    }
	}
	nStillRunning += file->cf_Running;
    }
    return(nStillRunning);
}


#ifdef CONFIG_FEATURE_CROND_CALL_SENDMAIL
static void
ForkJob(const char *user, CronLine *line, int mailFd,
	const char *prog, const char *cmd, const char *arg, const char *mailf)
{
    /*
     * Fork as the user in question and run program
     */
    pid_t pid = fork();

    line->cl_Pid = pid;
    if (pid == 0) {
	/*
	 * CHILD
	 */

	/*
	 * Change running state to the user in question
	 */

	if (ChangeUser(user) < 0)
	    exit(0);

#ifdef FEATURE_DEBUG_OPT
	if (DebugOpt)
	    log("\005Child Running %s\n", prog);
#endif

	if (mailFd >= 0) {
	    dup2(mailFd, mailf != NULL);
	    dup2((mailf ? mailFd : 1), 2);
	    close(mailFd);
	}
	execl(prog, prog, cmd, arg, NULL);
	log("\024unable to exec, user %s cmd %s %s %s\n", user,
	    prog, cmd, arg);
	if(mailf)
	    fdprintf(1, "Exec failed: %s -c %s\n", prog, arg);
	exit(0);
    } else if (pid < 0) {
	/*
	 * FORK FAILED
	 */
	log("\024couldn't fork, user %s\n", user);
	line->cl_Pid = 0;
	if(mailf)
	    remove(mailf);
    } else if(mailf) {
	/*
	 * PARENT, FORK SUCCESS
	 *
	 * rename mail-file based on pid of process
	 */
	char mailFile2[128];

	snprintf(mailFile2, sizeof(mailFile2), TMPDIR "/cron.%s.%d",
				    user, pid);
	rename(mailf, mailFile2);
    }
    /*
     * Close the mail file descriptor.. we can't just leave it open in
     * a structure, closing it later, because we might run out of descriptors
     */

    if (mailFd >= 0)
	close(mailFd);
}

static void
RunJob(const char *user, CronLine *line)
{
    char mailFile[128];
    int mailFd;

    line->cl_Pid = 0;
    line->cl_MailFlag = 0;

    /*
     * open mail file - owner root so nobody can screw with it.
     */

    snprintf(mailFile, sizeof(mailFile), TMPDIR "/cron.%s.%d",
	     user, getpid());
    mailFd = open(mailFile, O_CREAT|O_TRUNC|O_WRONLY|O_EXCL|O_APPEND, 0600);

    if (mailFd >= 0) {
	line->cl_MailFlag = 1;
	fdprintf(mailFd, "To: %s\nSubject: cron: %s\n\n", user,
						    line->cl_Shell);
	line->cl_MailPos = lseek(mailFd, 0, 1);
    } else {
	    log("\024unable to create mail file user %s file %s, output to /dev/null\n",
			user, mailFile);
    }

    ForkJob(user, line, mailFd, def_sh, "-c", line->cl_Shell, mailFile);
}

/*
 * EndJob - called when job terminates and when mail terminates
 */

static void
EndJob(const char *user, CronLine *line)
{
    int mailFd;
    char mailFile[128];
    struct stat sbuf;

    /*
     * No job
     */

    if (line->cl_Pid <= 0) {
	line->cl_Pid = 0;
	return;
    }

    /*
     * End of job and no mail file
     * End of sendmail job
     */

    snprintf(mailFile, sizeof(mailFile), TMPDIR "/cron.%s.%d",
	     user, line->cl_Pid);
    line->cl_Pid = 0;

    if (line->cl_MailFlag != 1)
	return;

    line->cl_MailFlag = 0;

    /*
     * End of primary job - check for mail file.  If size has increased and
     * the file is still valid, we sendmail it.
     */

    mailFd = open(mailFile, O_RDONLY);
    remove(mailFile);
    if (mailFd < 0) {
	return;
    }

    if (fstat(mailFd, &sbuf) < 0 ||
	sbuf.st_uid != DaemonUid ||
	sbuf.st_nlink != 0 ||
	sbuf.st_size == line->cl_MailPos ||
	!S_ISREG(sbuf.st_mode)
    ) {
	close(mailFd);
	return;
    }
    ForkJob(user, line, mailFd, SENDMAIL, SENDMAIL_ARGS, NULL);
}
#else
/* crond whithout sendmail */

static void
RunJob(const char *user, CronLine *line)
{
	/*
     * Fork as the user in question and run program
	 */
    pid_t pid = fork();

    if (pid == 0) {
	/*
	 * CHILD
	 */

	/*
	 * Change running state to the user in question
	 */

	if (ChangeUser(user) < 0)
	    exit(0);

#ifdef FEATURE_DEBUG_OPT
	if (DebugOpt)
	    log("\005Child Running %s\n", def_sh);
#endif

	execl(def_sh, def_sh, "-c", line->cl_Shell, NULL);
	log("\024unable to exec, user %s cmd %s -c %s\n", user,
	    def_sh, line->cl_Shell);
	exit(0);
    } else if (pid < 0) {
	/*
	 * FORK FAILED
	 */
	log("\024couldn't fork, user %s\n", user);
	pid = 0;
    }
    line->cl_Pid = pid;
}
#endif /* CONFIG_FEATURE_CROND_CALL_SENDMAIL */