xref: /freebsd/usr.sbin/ppp/chat.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1) 
1 /*-
2  * Copyright (c) 1998 Brian Somers <brian@Awfulhak.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include <sys/param.h>
30 #include <netinet/in.h>
31 #include <netinet/in_systm.h>
32 #include <netinet/ip.h>
33 #include <sys/socket.h>
34 #include <sys/un.h>
35 
36 #include <errno.h>
37 #include <fcntl.h>
38 #include <paths.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <sys/wait.h>
43 #include <termios.h>
44 #include <unistd.h>
45 
46 #include "layer.h"
47 #include "mbuf.h"
48 #include "log.h"
49 #include "defs.h"
50 #include "timer.h"
51 #include "lqr.h"
52 #include "hdlc.h"
53 #include "throughput.h"
54 #include "fsm.h"
55 #include "lcp.h"
56 #include "ccp.h"
57 #include "link.h"
58 #include "async.h"
59 #include "descriptor.h"
60 #include "physical.h"
61 #include "chat.h"
62 #include "mp.h"
63 #include "auth.h"
64 #include "chap.h"
65 #include "slcompress.h"
66 #include "iplist.h"
67 #include "ncpaddr.h"
68 #include "ipcp.h"
69 #include "filter.h"
70 #include "cbcp.h"
71 #include "command.h"
72 #include "datalink.h"
73 #ifndef NORADIUS
74 #include "radius.h"
75 #endif
76 #include "ipv6cp.h"
77 #include "ncp.h"
78 #include "bundle.h"
79 #include "id.h"
80 
81 #define BUFLEFT(c) (sizeof (c)->buf - ((c)->bufend - (c)->buf))
82 
83 static void ExecStr(struct physical *, char *, char *, int);
84 static char *ExpandString(struct chat *, const char *, char *, int, int);
85 
86 static void
87 chat_PauseTimer(void *v)
88 {
89   struct chat *c = (struct chat *)v;
90   timer_Stop(&c->pause);
91   c->pause.load = 0;
92 }
93 
94 static void
95 chat_Pause(struct chat *c, u_long load)
96 {
97   timer_Stop(&c->pause);
98   c->pause.load += load;
99   c->pause.func = chat_PauseTimer;
100   c->pause.name = "chat pause";
101   c->pause.arg = c;
102   timer_Start(&c->pause);
103 }
104 
105 static void
106 chat_TimeoutTimer(void *v)
107 {
108   struct chat *c = (struct chat *)v;
109   timer_Stop(&c->timeout);
110   c->TimedOut = 1;
111 }
112 
113 static void
114 chat_SetTimeout(struct chat *c)
115 {
116   timer_Stop(&c->timeout);
117   if (c->TimeoutSec > 0) {
118     c->timeout.load = SECTICKS * c->TimeoutSec;
119     c->timeout.func = chat_TimeoutTimer;
120     c->timeout.name = "chat timeout";
121     c->timeout.arg = c;
122     timer_Start(&c->timeout);
123   }
124 }
125 
126 static char *
127 chat_NextChar(char *ptr, char ch)
128 {
129   for (; *ptr; ptr++)
130     if (*ptr == ch)
131       return ptr;
132     else if (*ptr == '\\')
133       if (*++ptr == '\0')
134         return NULL;
135 
136   return NULL;
137 }
138 
139 static int
140 chat_UpdateSet(struct fdescriptor *d, fd_set *r, fd_set *w, fd_set *e, int *n)
141 {
142   struct chat *c = descriptor2chat(d);
143   int special, gotabort, gottimeout, needcr;
144   int TimedOut = c->TimedOut;
145   static char arg_term;		/* An empty string */
146 
147   if (c->pause.state == TIMER_RUNNING)
148     return 0;
149 
150   if (TimedOut) {
151     log_Printf(LogCHAT, "Expect timeout\n");
152     if (c->nargptr == NULL)
153       c->state = CHAT_FAILED;
154     else {
155       /* c->state = CHAT_EXPECT; */
156       c->argptr = &arg_term;
157     }
158     c->TimedOut = 0;
159   }
160 
161   if (c->state != CHAT_EXPECT && c->state != CHAT_SEND)
162     return 0;
163 
164   gottimeout = gotabort = 0;
165 
166   if (c->arg < c->argc && (c->arg < 0 || *c->argptr == '\0')) {
167     /* Go get the next string */
168     if (c->arg < 0 || c->state == CHAT_SEND)
169       c->state = CHAT_EXPECT;
170     else
171       c->state = CHAT_SEND;
172 
173     special = 1;
174     while (special && (c->nargptr || c->arg < c->argc - 1)) {
175       if (c->arg < 0 || (!TimedOut && c->state == CHAT_SEND))
176         c->nargptr = NULL;
177 
178       if (c->nargptr != NULL) {
179         /* We're doing expect-send-expect.... */
180         c->argptr = c->nargptr;
181         /* Put the '-' back in case we ever want to rerun our script */
182         c->nargptr[-1] = '-';
183         c->nargptr = chat_NextChar(c->nargptr, '-');
184         if (c->nargptr != NULL)
185           *c->nargptr++ = '\0';
186       } else {
187         int minus;
188 
189         if ((c->argptr = c->argv[++c->arg]) == NULL) {
190           /* End of script - all ok */
191           c->state = CHAT_DONE;
192           return 0;
193         }
194 
195         if (c->state == CHAT_EXPECT) {
196           /* Look for expect-send-expect sequence */
197           c->nargptr = c->argptr;
198           minus = 0;
199           while ((c->nargptr = chat_NextChar(c->nargptr, '-'))) {
200             c->nargptr++;
201             minus++;
202           }
203 
204           if (minus % 2)
205             log_Printf(LogWARN, "chat_UpdateSet: \"%s\": Uneven number of"
206                       " '-' chars, all ignored\n", c->argptr);
207           else if (minus) {
208             c->nargptr = chat_NextChar(c->argptr, '-');
209             *c->nargptr++ = '\0';
210           }
211         }
212       }
213 
214       /*
215        * c->argptr now temporarily points into c->script (via c->argv)
216        * If it's an expect-send-expect sequence, we've just got the correct
217        * portion of that sequence.
218        */
219 
220       needcr = c->state == CHAT_SEND &&
221                (*c->argptr != '!' || c->argptr[1] == '!');
222 
223       /* We leave room for a potential HDLC header in the target string */
224       ExpandString(c, c->argptr, c->exp + 2, sizeof c->exp - 2, needcr);
225 
226       /*
227        * Now read our string.  If it's not a special string, we unset
228        * ``special'' to break out of the loop.
229        */
230       if (gotabort) {
231         if (c->abort.num < MAXABORTS) {
232           int len, i;
233 
234           len = strlen(c->exp+2);
235           for (i = 0; i < c->abort.num; i++)
236             if (len > c->abort.string[i].len) {
237               int last;
238 
239               for (last = c->abort.num; last > i; last--) {
240                 c->abort.string[last].data = c->abort.string[last-1].data;
241                 c->abort.string[last].len = c->abort.string[last-1].len;
242               }
243               break;
244             }
245           c->abort.string[i].len = len;
246           if ((c->abort.string[i].data = (char *)malloc(len+1)) != NULL) {
247             memcpy(c->abort.string[i].data, c->exp+2, len+1);
248             c->abort.num++;
249 	  }
250         } else
251           log_Printf(LogERROR, "chat_UpdateSet: too many abort strings\n");
252         gotabort = 0;
253       } else if (gottimeout) {
254         c->TimeoutSec = atoi(c->exp + 2);
255         if (c->TimeoutSec <= 0)
256           c->TimeoutSec = 30;
257         gottimeout = 0;
258       } else if (c->nargptr == NULL && !strcmp(c->exp+2, "ABORT"))
259         gotabort = 1;
260       else if (c->nargptr == NULL && !strcmp(c->exp+2, "TIMEOUT"))
261         gottimeout = 1;
262       else {
263         if (c->exp[2] == '!' && c->exp[3] != '!')
264           ExecStr(c->physical, c->exp + 3, c->exp + 3, sizeof c->exp - 3);
265 
266         if (c->exp[2] == '\0') {
267           /* Empty string, reparse (this may be better as a `goto start') */
268           c->argptr = &arg_term;
269           return chat_UpdateSet(d, r, w, e, n);
270         }
271 
272         special = 0;
273       }
274     }
275 
276     if (special) {
277       if (gottimeout)
278         log_Printf(LogWARN, "chat_UpdateSet: TIMEOUT: Argument expected\n");
279       else if (gotabort)
280         log_Printf(LogWARN, "chat_UpdateSet: ABORT: Argument expected\n");
281 
282       /* End of script - all ok */
283       c->state = CHAT_DONE;
284       return 0;
285     }
286 
287     /* set c->argptr to point in the right place */
288     c->argptr = c->exp + (c->exp[2] == '!' ? 3 : 2);
289     c->arglen = strlen(c->argptr);
290 
291     if (c->state == CHAT_EXPECT) {
292       /* We must check to see if the string's already been found ! */
293       char *begin, *end;
294 
295       end = c->bufend - c->arglen + 1;
296       if (end < c->bufstart)
297         end = c->bufstart;
298       for (begin = c->bufstart; begin < end; begin++)
299         if (!strncmp(begin, c->argptr, c->arglen)) {
300           c->bufstart = begin + c->arglen;
301           c->argptr += c->arglen;
302           c->arglen = 0;
303           /* Continue - we've already read our expect string */
304           return chat_UpdateSet(d, r, w, e, n);
305         }
306 
307       log_Printf(LogCHAT, "Expect(%d): %s\n", c->TimeoutSec, c->argptr);
308       chat_SetTimeout(c);
309     }
310   }
311 
312   /*
313    * We now have c->argptr pointing at what we want to expect/send and
314    * c->state saying what we want to do... we now know what to put in
315    * the fd_set :-)
316    */
317 
318   if (c->state == CHAT_EXPECT)
319     return physical_doUpdateSet(&c->physical->desc, r, NULL, e, n, 1);
320   else
321     return physical_doUpdateSet(&c->physical->desc, NULL, w, e, n, 1);
322 }
323 
324 static int
325 chat_IsSet(struct fdescriptor *d, const fd_set *fdset)
326 {
327   struct chat *c = descriptor2chat(d);
328   return c->argptr && physical_IsSet(&c->physical->desc, fdset);
329 }
330 
331 static void
332 chat_UpdateLog(struct chat *c, int in)
333 {
334   if (log_IsKept(LogCHAT) || log_IsKept(LogCONNECT)) {
335     /*
336      * If a linefeed appears in the last `in' characters of `c's input
337      * buffer, output from there, all the way back to the last linefeed.
338      * This is called for every read of `in' bytes.
339      */
340     char *ptr, *end, *stop, ch;
341     int level;
342 
343     level = log_IsKept(LogCHAT) ? LogCHAT : LogCONNECT;
344     if (in == -1)
345       end = ptr = c->bufend;
346     else {
347       ptr = c->bufend - in;
348       for (end = c->bufend - 1; end >= ptr; end--)
349         if (*end == '\n')
350           break;
351     }
352 
353     if (end >= ptr) {
354       for (ptr = c->bufend - (in == -1 ? 1 : in + 1); ptr >= c->bufstart; ptr--)
355         if (*ptr == '\n')
356           break;
357       ptr++;
358       stop = NULL;
359       while (stop < end) {
360         if ((stop = memchr(ptr, '\n', end - ptr)) == NULL)
361           stop = end;
362         ch = *stop;
363         *stop = '\0';
364         if (level == LogCHAT || strstr(ptr, "CONNECT"))
365           log_Printf(level, "Received: %s\n", ptr);
366         *stop = ch;
367         ptr = stop + 1;
368       }
369     }
370   }
371 }
372 
373 static void
374 chat_Read(struct fdescriptor *d, struct bundle *bundle __unused,
375 	  const fd_set *fdset __unused)
376 {
377   struct chat *c = descriptor2chat(d);
378 
379   if (c->state == CHAT_EXPECT) {
380     ssize_t in;
381     char *abegin, *ebegin, *begin, *aend, *eend, *end;
382     int n;
383 
384     /*
385      * XXX - should this read only 1 byte to guarantee that we don't
386      * swallow any ppp talk from the peer ?
387      */
388     in = BUFLEFT(c);
389     if (in > (ssize_t)sizeof c->buf / 2)
390       in = sizeof c->buf / 2;
391 
392     in = physical_Read(c->physical, c->bufend, in);
393     if (in <= 0)
394       return;
395 
396     /* `begin' and `end' delimit where we're going to strncmp() from */
397     ebegin = c->bufend - c->arglen + 1;
398     eend = ebegin + in;
399     if (ebegin < c->bufstart)
400       ebegin = c->bufstart;
401 
402     if (c->abort.num) {
403       abegin = c->bufend - c->abort.string[0].len + 1;
404       aend = c->bufend - c->abort.string[c->abort.num-1].len + in + 1;
405       if (abegin < c->bufstart)
406         abegin = c->bufstart;
407     } else {
408       abegin = ebegin;
409       aend = eend;
410     }
411     begin = abegin < ebegin ? abegin : ebegin;
412     end = aend < eend ? eend : aend;
413 
414     c->bufend += in;
415 
416     chat_UpdateLog(c, in);
417 
418     if (c->bufend > c->buf + sizeof c->buf / 2) {
419       /* Shuffle our receive buffer back a bit */
420       int chop;
421 
422       for (chop = begin - c->buf; chop; chop--)
423         if (c->buf[chop] == '\n')
424           /* found some already-logged garbage to remove :-) */
425           break;
426 
427       if (!chop)
428         chop = begin - c->buf;
429 
430       if (chop) {
431         char *from, *to;
432 
433         to = c->buf;
434         from = to + chop;
435         while (from < c->bufend)
436           *to++ = *from++;
437         c->bufstart -= chop;
438         c->bufend -= chop;
439         begin -= chop;
440         end -= chop;
441         abegin -= chop;
442         aend -= chop;
443         ebegin -= chop;
444         eend -= chop;
445       }
446     }
447 
448     for (; begin < end; begin++)
449       if (begin >= ebegin && begin < eend &&
450           !strncmp(begin, c->argptr, c->arglen)) {
451         /* Got it ! */
452         timer_Stop(&c->timeout);
453         if (memchr(begin + c->arglen - 1, '\n',
454             c->bufend - begin - c->arglen + 1) == NULL) {
455           /* force it into the log */
456           end = c->bufend;
457           c->bufend = begin + c->arglen;
458           chat_UpdateLog(c, -1);
459           c->bufend = end;
460         }
461         c->bufstart = begin + c->arglen;
462         c->argptr += c->arglen;
463         c->arglen = 0;
464         break;
465       } else if (begin >= abegin && begin < aend) {
466         for (n = c->abort.num - 1; n >= 0; n--) {
467           if (begin + c->abort.string[n].len > c->bufend)
468             break;
469           if (!strncmp(begin, c->abort.string[n].data,
470                        c->abort.string[n].len)) {
471             if (memchr(begin + c->abort.string[n].len - 1, '\n',
472                 c->bufend - begin - c->abort.string[n].len + 1) == NULL) {
473               /* force it into the log */
474               end = c->bufend;
475               c->bufend = begin + c->abort.string[n].len;
476               chat_UpdateLog(c, -1);
477               c->bufend = end;
478             }
479             c->bufstart = begin + c->abort.string[n].len;
480             c->state = CHAT_FAILED;
481             return;
482           }
483         }
484       }
485   }
486 }
487 
488 static int
489 chat_Write(struct fdescriptor *d, struct bundle *bundle __unused,
490 	   const fd_set *fdset __unused)
491 {
492   struct chat *c = descriptor2chat(d);
493   int result = 0;
494 
495   if (c->state == CHAT_SEND) {
496     int wrote;
497 
498     if (strstr(c->argv[c->arg], "\\P"))            /* Don't log the password */
499       log_Printf(LogCHAT, "Send: %s\n", c->argv[c->arg]);
500     else {
501       int sz;
502 
503       sz = c->arglen - 1;
504       while (sz >= 0 && c->argptr[sz] == '\n')
505         sz--;
506       log_Printf(LogCHAT, "Send: %.*s\n", sz + 1, c->argptr);
507     }
508 
509     if (physical_IsSync(c->physical)) {
510       /*
511        * XXX: Fix me
512        * This data should be stuffed down through the link layers
513        */
514       /* There's always room for the HDLC header */
515       c->argptr -= 2;
516       c->arglen += 2;
517       memcpy(c->argptr, "\377\003", 2);	/* Prepend HDLC header */
518     }
519 
520     wrote = physical_Write(c->physical, c->argptr, c->arglen);
521     result = wrote > 0 ? 1 : 0;
522     if (wrote == -1) {
523       if (errno != EINTR) {
524         log_Printf(LogWARN, "chat_Write: %s\n", strerror(errno));
525 	result = -1;
526       }
527       if (physical_IsSync(c->physical)) {
528         c->argptr += 2;
529         c->arglen -= 2;
530       }
531     } else if (wrote < 2 && physical_IsSync(c->physical)) {
532       /* Oops - didn't even write our HDLC header ! */
533       c->argptr += 2;
534       c->arglen -= 2;
535     } else {
536       c->argptr += wrote;
537       c->arglen -= wrote;
538     }
539   }
540 
541   return result;
542 }
543 
544 void
545 chat_Init(struct chat *c, struct physical *p)
546 {
547   c->desc.type = CHAT_DESCRIPTOR;
548   c->desc.UpdateSet = chat_UpdateSet;
549   c->desc.IsSet = chat_IsSet;
550   c->desc.Read = chat_Read;
551   c->desc.Write = chat_Write;
552   c->physical = p;
553   *c->script = '\0';
554   c->argc = 0;
555   c->arg = -1;
556   c->argptr = NULL;
557   c->nargptr = NULL;
558   c->bufstart = c->bufend = c->buf;
559 
560   memset(&c->pause, '\0', sizeof c->pause);
561   memset(&c->timeout, '\0', sizeof c->timeout);
562 }
563 
564 int
565 chat_Setup(struct chat *c, const char *data, const char *phone)
566 {
567   c->state = CHAT_EXPECT;
568 
569   if (data == NULL) {
570     *c->script = '\0';
571     c->argc = 0;
572   } else {
573     strncpy(c->script, data, sizeof c->script - 1);
574     c->script[sizeof c->script - 1] = '\0';
575     c->argc = MakeArgs(c->script, c->argv, VECSIZE(c->argv), PARSE_NOHASH);
576   }
577 
578   c->arg = -1;
579   c->argptr = NULL;
580   c->nargptr = NULL;
581 
582   c->TimeoutSec = 30;
583   c->TimedOut = 0;
584   c->phone = phone;
585   c->abort.num = 0;
586 
587   timer_Stop(&c->pause);
588   timer_Stop(&c->timeout);
589 
590   return c->argc >= 0;
591 }
592 
593 void
594 chat_Finish(struct chat *c)
595 {
596   timer_Stop(&c->pause);
597   timer_Stop(&c->timeout);
598   while (c->abort.num)
599     free(c->abort.string[--c->abort.num].data);
600   c->abort.num = 0;
601 }
602 
603 void
604 chat_Destroy(struct chat *c)
605 {
606   chat_Finish(c);
607 }
608 
609 /*
610  *  \c	don't add a cr
611  *  \d  Sleep a little (delay 2 seconds
612  *  \n  Line feed character
613  *  \P  Auth Key password
614  *  \p  pause 0.25 sec
615  *  \r	Carrige return character
616  *  \s  Space character
617  *  \T  Telephone number(s) (defined via `set phone')
618  *  \t  Tab character
619  *  \U  Auth User
620  */
621 static char *
622 ExpandString(struct chat *c, const char *str, char *result, int reslen, int cr)
623 {
624   int len;
625 
626   result[--reslen] = '\0';
627   while (*str && reslen > 0) {
628     switch (*str) {
629     case '\\':
630       str++;
631       switch (*str) {
632       case 'c':
633 	cr = 0;
634 	break;
635       case 'd':		/* Delay 2 seconds */
636         chat_Pause(c, 2 * SECTICKS);
637 	break;
638       case 'p':
639         chat_Pause(c, SECTICKS / 4);
640 	break;		/* Delay 0.25 seconds */
641       case 'n':
642 	*result++ = '\n';
643 	reslen--;
644 	break;
645       case 'r':
646 	*result++ = '\r';
647 	reslen--;
648 	break;
649       case 's':
650 	*result++ = ' ';
651 	reslen--;
652 	break;
653       case 't':
654 	*result++ = '\t';
655 	reslen--;
656 	break;
657       case 'P':
658 	strncpy(result, c->physical->dl->bundle->cfg.auth.key, reslen);
659         len = strlen(result);
660 	reslen -= len;
661 	result += len;
662 	break;
663       case 'T':
664         if (c->phone) {
665           strncpy(result, c->phone, reslen);
666           len = strlen(result);
667           reslen -= len;
668           result += len;
669         }
670 	break;
671       case 'U':
672 	strncpy(result, c->physical->dl->bundle->cfg.auth.name, reslen);
673         len = strlen(result);
674 	reslen -= len;
675 	result += len;
676 	break;
677       default:
678 	reslen--;
679 	*result++ = *str;
680 	break;
681       }
682       if (*str)
683 	str++;
684       break;
685     case '^':
686       str++;
687       if (*str) {
688 	*result++ = *str++ & 0x1f;
689 	reslen--;
690       }
691       break;
692     default:
693       *result++ = *str++;
694       reslen--;
695       break;
696     }
697   }
698   if (--reslen > 0) {
699     if (cr)
700       *result++ = '\r';
701   }
702   if (--reslen > 0)
703     *result++ = '\0';
704   return (result);
705 }
706 
707 static void
708 ExecStr(struct physical *physical, char *command, char *out, int olen)
709 {
710   pid_t pid;
711   int fids[2];
712   char *argv[MAXARGS], *vector[MAXARGS], *startout, *endout;
713   int stat, nb, argc, i;
714 
715   log_Printf(LogCHAT, "Exec: %s\n", command);
716   if ((argc = MakeArgs(command, vector, VECSIZE(vector),
717                        PARSE_REDUCE|PARSE_NOHASH)) <= 0) {
718     if (argc < 0)
719       log_Printf(LogWARN, "Syntax error in exec command\n");
720     *out = '\0';
721     return;
722   }
723 
724   if (pipe(fids) < 0) {
725     log_Printf(LogCHAT, "Unable to create pipe in ExecStr: %s\n",
726 	      strerror(errno));
727     *out = '\0';
728     return;
729   }
730   if ((pid = fork()) == 0) {
731     command_Expand(argv, argc, (char const *const *)vector,
732                    physical->dl->bundle, 0, getpid());
733     close(fids[0]);
734     timer_TermService();
735     if (fids[1] == STDIN_FILENO)
736       fids[1] = dup(fids[1]);
737     dup2(physical->fd, STDIN_FILENO);
738     dup2(fids[1], STDERR_FILENO);
739     dup2(STDIN_FILENO, STDOUT_FILENO);
740     close(3);
741     if (open(_PATH_TTY, O_RDWR) != 3)
742       open(_PATH_DEVNULL, O_RDWR);	/* Leave it closed if it fails... */
743     for (i = getdtablesize(); i > 3; i--)
744       fcntl(i, F_SETFD, 1);
745 #ifndef NOSUID
746     setuid(ID0realuid());
747 #endif
748     execvp(argv[0], argv);
749     fprintf(stderr, "execvp: %s: %s\n", argv[0], strerror(errno));
750     _exit(127);
751   } else {
752     char *name = strdup(vector[0]);
753 
754     close(fids[1]);
755     endout = out + olen - 1;
756     startout = out;
757     while (out < endout) {
758       nb = read(fids[0], out, 1);
759       if (nb <= 0)
760 	break;
761       out++;
762     }
763     *out = '\0';
764     close(fids[0]);
765     close(fids[1]);
766     waitpid(pid, &stat, WNOHANG);
767     if (WIFSIGNALED(stat)) {
768       log_Printf(LogWARN, "%s: signal %d\n", name, WTERMSIG(stat));
769       free(name);
770       *out = '\0';
771       return;
772     } else if (WIFEXITED(stat)) {
773       switch (WEXITSTATUS(stat)) {
774         case 0:
775           free(name);
776           break;
777         case 127:
778           log_Printf(LogWARN, "%s: %s\n", name, startout);
779           free(name);
780           *out = '\0';
781           return;
782           break;
783         default:
784           log_Printf(LogWARN, "%s: exit %d\n", name, WEXITSTATUS(stat));
785           free(name);
786           *out = '\0';
787           return;
788           break;
789       }
790     } else {
791       log_Printf(LogWARN, "%s: Unexpected exit result\n", name);
792       free(name);
793       *out = '\0';
794       return;
795     }
796   }
797 }
798