Source Code 1992 March/Source_Code_CD-ROM_Walnut_Creek_March_1992.iso/usenet/altsrcs/2/2030/expired.c

C/C++ Source or Header | 1990-12-28 | 4.2 KB | 231 lines

/*
 * expired.c
 * 11/6/90
 * John A. Limpert ([e-mail])
 *
 * 'smart' news expiration daemon for UNIX System V Release 3
 *
 * This program will expire the oldest 1/3 of news whenever
 * free space is less than 10% on the news filesystem.
 */

#include <stdio.h>
#include <sys/types.h>
#include <sys/statfs.h>
#include <sys/stat.h>
#include <signal.h>
#include <errno.h>
#include <time.h>
#include <string.h>

#ifndef SPOOL
#define SPOOL    "/usr/spool/news"        /* news spool directory */
#endif

#ifndef ETFILE
#define ETFILE    "/usr/lib/news/expire_time"    /* expiration cutoff time */
#endif

#ifndef LOGFILE
#define LOGFILE    "/usr/lib/news/expired.log"    /* expired log file */
#endif

#ifndef MINFREE
#define MINFREE    0.1                /* desired free space */
#endif

/* prototype expire command */
#ifndef CMD
#define CMD    "/bin/su news -c \"/usr/lib/news/expire -e%f -E%f\""
#endif

/* seconds in day */
#define DAY    (24L*60L*60L)

struct utimbuf {
  time_t actime;    /* access time */
  time_t modtime;    /* modification time */
};

/* external */
extern void exit();
extern void perror();
extern unsigned sleep();
extern time_t time();

/* forward */
extern time_t get_mtime();
extern void log();
extern void set_mtime();

/* program name */
char *pname;

/*ARGSUSED*/
int
main(argc, argv)
int argc;
char **argv;
{
  struct statfs part_stat;
  time_t delta, now, oldest_news;
  double keep;
  char cmdbuf[256];
  int pid;
  long minfree;

  pname = argv[0];

  /* ignore user signals */
  (void) signal(SIGHUP, SIG_IGN);
  (void) signal(SIGINT, SIG_IGN);
  (void) signal(SIGQUIT, SIG_IGN);

  /* go into background */
  if ((pid = fork()) < 0) {
    perror(pname);
    exit(1);
  }
  if (pid != 0)
    exit(0);

  log("running...");

  for (;;) {
    /* wait for exhaustion of disk space */
    for (;;) {
      if (statfs(SPOOL, &part_stat, sizeof(struct statfs), 0) < 0) {
    perror(SPOOL);
    exit(1);
      }

      minfree = part_stat.f_blocks*MINFREE;

      if (part_stat.f_bfree < minfree)
    break;

      (void) sleep(60);
    }

    /* discard oldest 1/3 of news */
    oldest_news = get_mtime(ETFILE);
    now = time((time_t *) 0);
    delta = now - oldest_news;
    delta = (delta*2)/3;
    oldest_news = now - delta;
    set_mtime(ETFILE, oldest_news);
    keep = ((double) delta)/((double) DAY);

    /* generate expire command */
    sprintf(cmdbuf, CMD, keep, keep);

    /* update log file */
    log(cmdbuf);

    /* run expire */
    if (system(cmdbuf) < 0) {
      perror(pname);
      exit(1);
    }
  }
  /*NOTREACHED*/
}

/* get_mtime -- get modification time of specified file */

time_t
get_mtime(path)
char *path;
{
  struct stat file_stat;
  struct utimbuf ut;
  int fd;

  /* does file exist? */
  if (stat(path, &file_stat) < 0 && errno == ENOENT) {
    /* create it */
    if ((fd = creat(path, 0)) < 0) {
      perror(path);
      exit(1);
    }
    if (close(fd) < 0) {
      perror(path);
      exit(1);
    }
    /* backdate two weeks */
    ut.actime = ut.modtime = time((time_t *) 0) - 14L*DAY;
    if (utime(path, &ut) < 0) {
      perror(path);
      exit(1);
    }
  }

  /* get inode info */
  if (stat(path, &file_stat) < 0) {
    perror(path);
    exit(1);
  }

  /* return modification time */
  return file_stat.st_mtime;
}

/* set_mtime -- set modification and access time of specified file */

void
set_mtime(path, t)
char *path;
time_t t;
{
  struct stat file_stat;
  struct utimbuf ut;
  int fd;

  /* does file exist? */
  if (stat(path, &file_stat) < 0 && errno == ENOENT) {
    /* create it */
    if ((fd = creat(path, 0)) < 0) {
      perror(path);
      exit(1);
    }
    if (close(fd) < 0) {
      perror(path);
      exit(1);
    }
  }

  /* record time in file inode */
  ut.actime = ut.modtime = t;
  if (utime(path, &ut) < 0) {
    perror(path);
    exit(1);
  }
}

/* log -- write time tagged string to log file */

void
log(s)
char *s;
{
  FILE *logf;
  time_t t;
  char *p, tbuf[32];

  /* open log file */
  if ((logf = fopen(LOGFILE, "a")) == NULL) {
    fprintf(stderr, "%s: can't append to %s\n", pname, LOGFILE);
    exit(1);
  }

  /* time in ASCII without newline */
  t = time((time_t *) 0);
  (void) strcpy(tbuf, ctime(&t));
  if ((p = strchr(tbuf, '\n')) != NULL)
      *p = '\0';

  /* append time tagged entry to log file */
  fprintf(logf, "%s: %s\n", tbuf, s);
  fclose(logf);
}