text: /* rcvtty.c -- a rcvmail program (a lot like rcvalert) handling IPC ttys
   *
   * This code is Copyright (c) 2002, by the authors of nmh.  See the
   * COPYRIGHT file in the root directory of the nmh distribution for
   * complete copyright information.
   */
  
  /* Changed to use getutent() and friends.  Assumes that when getutent() exists,
   * a number of other things also exist.  Please check.
   * Ruud de Rooij <ruud@ruud.org>  Sun, 28 May 2000 17:28:55 +0200
   */
  
  #include "h/mh.h"
  #include "sbr/fmt_new.h"
  #include "scansbr.h"
  #include "sbr/getarguments.h"
  #include "sbr/smatch.h"
  #include "sbr/ambigsw.h"
  #include "sbr/print_version.h"
  #include "sbr/print_help.h"
  #include "sbr/error.h"
  #include "h/signals.h"
  #include <setjmp.h>
  #include "h/fmt_scan.h"
  #include "h/tws.h"
  #include "h/mts.h"
  #include "h/done.h"
  #include "h/utils.h"
  #include "sbr/m_mktemp.h"
  #include <fcntl.h>
  
  #ifdef HAVE_GETUTXENT
  #include <utmpx.h>
  #endif /* HAVE_GETUTXENT */
  
  #define	SCANFMT	\
  "%2(hour{dtimenow}):%02(min{dtimenow}): %<(size)%5(size) %>%<{encrypted}E%>\
  %<(mymbox{from})%<{to}To:%14(friendly{to})%>%>%<(zero)%17(friendly{from})%>  \
  %{subject}%<{body}<<%{body}>>%>"
  
  #define RCVTTY_SWITCHES \
      X("biff", 0, BIFFSW) \
      X("form formatfile", 0, FORMSW) \
      X("format string", 5, FMTSW) \
      X("width columns", 0, WIDTHSW) \
      X("newline", 0, NLSW) \
      X("nonewline", 0, NNLSW) \
      X("bell", 0, BELSW) \
      X("nobell", 0, NBELSW) \
      X("version", 0, VERSIONSW) \
      X("help", 0, HELPSW) \
  
  #define X(sw, minchars, id) id,
  DEFINE_SWITCH_ENUM(RCVTTY);
  #undef X
  
  #define X(sw, minchars, id) { sw, minchars, id },
  DEFINE_SWITCH_ARRAY(RCVTTY, switches);
  #undef X
  
  static jmp_buf myctx;
  static bool bell = true;
  static bool newline = true;
  static bool biff;
  static int width = -1;
  static char *form = NULL;
  static char *format = NULL;
  
  /*
   * static prototypes
   */
  static void alrmser (int);
  static int message_fd (char **);
  static int header_fd (void);
  #if HAVE_GETUTXENT
  static void alert (char *, int);
  #endif /* HAVE_GETUTXENT */
  
  
  int
  main (int argc, char **argv)
  {
      int md, vecp = 0;
      char *cp, *user, buf[BUFSIZ];
      char **argp, **arguments, *vec[MAXARGS];
      struct utmpx *utp;
  
      if (nmh_init(argv[0], true, false)) { return 1; }
  
      mts_init ();
      arguments = getarguments (invo_name, argc, argv, 1);
      argp = arguments;
  
      while ((cp = *argp++)) {
  	if (*cp == '-') {
  	    switch (smatch (++cp, switches)) {
  		case AMBIGSW:
  		    ambigsw (cp, switches);
  		    done (1);
  		case UNKWNSW:
  		    vec[vecp++] = --cp;
  		    continue;
  
  		case HELPSW:
  		    snprintf (buf, sizeof(buf), "%s [command ...]", invo_name);
  		    print_help (buf, switches, 1);
  		    done (0);
  		case VERSIONSW:
  		    print_version(invo_name);
  		    done (0);
  
  		case BIFFSW:
  		    biff = true;
  		    continue;
  
  		case FORMSW:
  		    if (!(form = *argp++) || *form == '-')
  			die("missing argument to %s", argp[-2]);
  		    format = NULL;
  		    continue;
  		case FMTSW:
  		    if (!(format = *argp++) || *format == '-')
  			die("missing argument to %s", argp[-2]);
  		    form = NULL;
  		    continue;
  
  		case WIDTHSW:
  		    if (!(cp = *argp++) || *cp == '-')
  			die("missing argument to %s", argp[-2]);
  		    width = atoi(cp);
  		    continue;
                  case NLSW:
                      newline = true;
                      continue;
                  case NNLSW:
                      newline = false;
                      continue;
                  case BELSW:
                      bell = true;
                      continue;
                  case NBELSW:
                      bell = false;
                      continue;
  
  	    }
  	}
  	vec[vecp++] = cp;
      }
      vec[vecp] = 0;
  
      if ((md = vecp ? message_fd (vec) : header_fd ()) == NOTOK)
  	exit(1);
  
  #if HAVE_GETUTXENT
      user = getusername(1);
  
      setutxent();
      while ((utp = getutxent()) != NULL) {
          if (utp->ut_type == USER_PROCESS && utp->ut_user[0] != 0
                 && utp->ut_line[0] != 0
                 && strncmp (user, utp->ut_user, sizeof(utp->ut_user)) == 0) {
  	    alert(utp->ut_line, md);
          }
      }
      endutxent();
  #else
      NMH_UNUSED (utp);
  #endif /* HAVE_GETUTXENT */
  
      exit(0);
  }
  
  
  static void
  alrmser (int i)
  {
      NMH_UNUSED (i);
  
      longjmp (myctx, 1);
  }
  
  
  static int
  message_fd (char **vec)
  {
      pid_t child_id;
      int bytes, seconds;
      int fd;
      char *tfile;
      struct stat st;
  
      if ((tfile = m_mktemp2(NULL, invo_name, &fd, NULL)) == NULL) {
  	inform("unable to create temporary file in %s", get_temp_dir());
  	return NOTOK;
      }
      (void) m_unlink(tfile);  /* Use fd, no longer need the file name. */
  
      if ((child_id = fork()) == NOTOK) {
  	/* fork error */
  	close (fd);
  	return header_fd ();
      }
      if (child_id) {
  	/* parent process */
  	if (!setjmp (myctx)) {
  	    SIGNAL (SIGALRM, alrmser);
  	    bytes = fstat(fileno (stdin), &st) != NOTOK ? (int) st.st_size : 100;
  
  	    /* amount of time to wait depends on message size */
  	    if (bytes <= 100) {
  		/* give at least 5 minutes */
  		seconds = 300;
  	    } else if (bytes >= 90000) {
  		/* but 30 minutes should be long enough */
  		seconds = 1800;
  	    } else {
  		seconds = (bytes / 60) + 300;
  	    }
  	    alarm ((unsigned int) seconds);
  	    pidwait(child_id, OK);
  	    alarm (0);
  
  	    if (fstat (fd, &st) != NOTOK && st.st_size > 0)
  		return fd;
  	} else {
  	    /*
  	     * Ruthlessly kill the child and anything
  	     * else in its process group.
  	     */
  	    killpg(child_id, SIGKILL);
  	}
  	close (fd);
  	return header_fd ();
      }
  
      /* child process */
      rewind (stdin);
      if (dup2 (fd, 1) == NOTOK || dup2 (fd, 2) == NOTOK)
  	_exit(1);
      setpgid(0, getpid());	/* put in own process group */
      if (execvp (vec[0], vec) == NOTOK) {
          _exit(1);
      }
  
      return NOTOK;
  }
  
  
  static int
  header_fd (void)
  {
      int fd;
      char *nfs;
      char *tfile = NULL;
      charstring_t scanl = NULL;
  
      if ((tfile = m_mktemp2(NULL, invo_name, &fd, NULL)) == NULL) {
  	inform("unable to create temporary file in %s", get_temp_dir());
          return NOTOK;
      }
      (void) m_unlink(tfile);  /* Use fd, no longer need the file name. */
  
      rewind (stdin);
  
      /* get new format string */
      nfs = new_fs (form, format, SCANFMT);
      scan (stdin, 0, 0, nfs, width, 0, 0, NULL, 0L, 0, &scanl);
      scan_finished ();
      if (newline) {
  	if (write (fd, "\n\r", 2) < 0) {
  	    advise (tfile, "write LF/CR");
  	}
      }
      if (write (fd, charstring_buffer (scanl), charstring_bytes (scanl)) < 0) {
  	advise (tfile, "write");
      }
      charstring_free (scanl);
      if (bell) {
          if (write (fd, "\007", 1) < 0) {
  	    advise (tfile, "write BEL");
          }
      }
  
      return fd;
  }
  
  
  #if HAVE_GETUTXENT
  static void
  alert (char *tty, int md)
  {
      int i, td, mask;
      char buffer[BUFSIZ], ttyspec[BUFSIZ];
      struct stat st;
  
      snprintf (ttyspec, sizeof(ttyspec), "/dev/%s", tty);
  
      /*
       * The mask depends on whether we are checking for
       * write permission based on `biff' or `mesg'.
       */
      mask = biff ? S_IEXEC : (S_IWRITE >> 3);
      if (stat (ttyspec, &st) == NOTOK || (st.st_mode & mask) == 0)
  	return;
  
      if (setjmp (myctx)) {
  	alarm (0);
  	return;
      }
      SIGNAL (SIGALRM, alrmser);
      alarm (2);
      td = open (ttyspec, O_WRONLY);
      alarm (0);
      if (td == NOTOK)
          return;
  
      lseek(md, 0, SEEK_SET);
  
      while ((i = read (md, buffer, sizeof(buffer))) > 0)
  	if (write (td, buffer, i) != i)
  	    break;
  
      close (td);
  }
  #endif /* HAVE_GETUTXENT */
  