text: /*
   * Copyright (c) 2018 Gilles Chehade <gilles@poolp.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include "includes.h"
  
  #include <sys/types.h>
  #include <sys/stat.h>
  
  #include <ctype.h>
  #include <err.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <limits.h>
  #include <netdb.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sysexits.h>
  #include <time.h>
  #include <unistd.h>
  
  static void	mboxfile_engine(const char *sender, const char *filename);
  
  int
  main(int argc, char *argv[])
  {
  	int	ch;
  	char   *sender = "<unknown>";
  
  	if (! geteuid())
  		errx(1, "mail.mboxfile: may not be executed as root");
  
  	while ((ch = getopt(argc, argv, "f:")) != -1) {
  		switch (ch) {
  		case 'f':
  			sender = optarg;
  			break;
  		default:
  			break;
  		}
  	}
  	argc -= optind;
  	argv += optind;
  
  	if (argc > 1)
  		errx(1, "mail.mboxfile: only one mboxfile is allowed");
  
  	mboxfile_engine(sender, argv[0]);
  
  	return (0);
  }
  
  static void
  mboxfile_engine(const char *sender, const char *filename)
  {
  	int	fd;
  	char	buf[26];
  	FILE    *fp;
  	char	*line = NULL;
  	size_t	linesize = 0;
  	ssize_t	linelen;
  	time_t	now;
  
  	time(&now);
  
  #ifndef O_EXLOCK
  #define O_EXLOCK 0
  #endif
  	fd = open(filename, O_CREAT | O_APPEND | O_WRONLY | O_EXLOCK, 0600);
  #ifndef HAVE_O_EXLOCK
  	/* XXX : do something! */
  #endif
  	if (fd == -1)
  		err(EX_TEMPFAIL, NULL);
  
  	if ((fp = fdopen(fd, "w")) == NULL)
  		err(EX_TEMPFAIL, NULL);
  
  	fprintf(fp, "From %s %s", sender, ctime_r(&now, (char *)&buf));
  	while ((linelen = getline(&line, &linesize, stdin)) != -1) {
  		line[strcspn(line, "\n")] = '\0';
  		if (strncmp(line, "From ", 5) == 0)
  			fprintf(fp, ">%s\n", line);
  		else
  			fprintf(fp, "%s\n", line);
  	}
  	fprintf(fp, "\n");
  	free(line);
  	if (ferror(stdin))
  		err(EX_TEMPFAIL, NULL);
  
  	if (fflush(fp) == EOF ||
  	    ferror(fp) ||
  	    (fsync(fd) == -1 && errno != EINVAL) ||
  	    fclose(fp) == EOF)
  		err(EX_TEMPFAIL, NULL);
  }
  