text: /* 1. Erase archive symbol table's timestamp from ar archives,
   * make it easy to `diff'.  (option -e)
   * 2. Check the sanity of timestamp. (option -c)
   *
   * $Id$
   */
  
  #include <errno.h>
  #include <fcntl.h>
  #include <getopt.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <time.h>
  #include <unistd.h>
  
  #define TSPOS	24		/* position of timestamp */
  #define TSLEN	10		/* length of timstamp string */
  #define BUFLEN	16		/* size of a temporary buffer */
  #define TDELAY	3		/* max delay allowed */
  #define COUNTER	"/tmp/bsdar-test-total"
  #define PASSED	"/tmp/bsdar-test-passed"
  
  #if BUFLEN < TSLEN
  #error Temporary buffer size too small
  #endif
  
  static void	usage(void);
  
  int
  main(int argc, char **argv)
  {
  	int opt;
  	char checktime;
  	char erasetime;
  	char buf[BUFLEN];
  	char *tc;
  	int fd;
  	int ts;
  	time_t now;
  	FILE *ct, *ps;
  
  
  	checktime = 0;
  	erasetime = 0;
  	tc = NULL;
  	while ((opt = getopt(argc, argv, "cet:")) != -1) {
  		switch(opt) {
  		case 'c':
  			checktime = 1;
  			break;
  		case 'e':
  			erasetime = 1;
  			break;
  		case 't':
  			tc = optarg;
  			break;
  		default:
  			usage();
  		}
  	}
  
  	argv += optind;
  	if (*argv == NULL)
  		usage();
  
  	for (; *argv != NULL; argv++) {
  		if (checktime) {
  			if ((fd = open(*argv, O_RDONLY)) == -1) {
  				fprintf(stderr,
  				    "open %s failed(%s), skipping time check...\n,",
  				    *argv, strerror(errno));
  				goto ctend;
  			}
  			if ((lseek(fd, TSPOS, SEEK_SET)) == -1) {
  				fprintf(stderr,
  				    "lseek %s failed(%s), skipping...\n,",
  				    *argv, strerror(errno));
  				goto ctend;
  			}
  			if ((read(fd, buf, TSLEN)) != TSLEN) {
  				fprintf(stderr,
  				    "read %s failed(%s), skipping...\n,",
  				    *argv, strerror(errno));
  				goto ctend;
  			}
  			buf[TSLEN] = '\0';
  			ts = atoi(buf);
  			now = time(NULL);
  			if (ts <= now && ts >= now - TDELAY) {
  				fprintf(stderr, "%s - timestamp ok\n", tc);
  				if ((ps = fopen(PASSED, "r")) != NULL) {
  					if (fgets(buf, TSLEN, ps) != buf)
  						perror("fgets");
  					snprintf(buf, sizeof buf, "%d\n",
  					    atoi(buf) + 1);
  					fclose(ps);
  				}
  				if ((ps = fopen(PASSED, "w")) != NULL) {
  					fputs(buf, ps);
  					fclose(ps);
  				}
  			} else {
  				fprintf(stderr, "%s - timestamp not ok\n", tc);
  			}
  			if ((ct = fopen(COUNTER, "r")) != NULL) {
  				if (fgets(buf, TSLEN, ct) != NULL)
  					perror("fgets");
  				snprintf(buf, sizeof buf, "%d\n",
  				    atoi(buf) + 1);
  				fclose(ct);
  			}
  			if ((ct = fopen(COUNTER, "w")) != NULL) {
  				fputs(buf, ct);
  				fclose(ct);
  			}
  
  		ctend:
  			close(fd);
  		}
  
  		if (erasetime) {
  			if ((fd = open(*argv, O_RDWR)) == -1) {
  				fprintf(stderr,
  				    "open %s failed(%s), skipping time check...\n,",
  				    *argv, strerror(errno));
  				goto etend;
  			}
  			if ((lseek(fd, TSPOS, SEEK_SET)) == -1) {
  				fprintf(stderr, "lseek %s failed(%s), skipping...,",
  					*argv, strerror(errno));
  				goto etend;
  			}
  			memset(buf, 32, TSLEN);
  			if ((write(fd, buf, TSLEN)) != TSLEN)
  				fprintf(stderr,
  				    "read %s failed(%s), skipping...\n,",
  				    *argv, strerror(errno));
  
  		etend:
  			close(fd);
  		}
  	}
  
  	exit(EXIT_SUCCESS);
  }
  
  static void
  usage(void)
  {
  	fprintf(stderr, "usage: teraser [-ce] [-t name] archive ...\n");
  	exit(EXIT_FAILURE);
  }
  