tcpu.c - plan9port - [fork] Plan 9 from user space
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tcpu.c (20341B)
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1 /*
2 * cpu.c - Make a connection to a cpu server
3 *
4 * Invoked by listen as 'cpu -R | -N service net netdir'
5 * by users as 'cpu [-h system] [-c cmd args ...]'
6 */
7
8 #include <u.h>
9 #include <libc.h>
10 #include <bio.h>
11 #include <auth.h>
12 #include <fcall.h>
13 #include <libsec.h>
14
15 #define Maxfdata 8192
16
17 void remoteside(int);
18 void fatal(int, char*, ...);
19 void lclnoteproc(int);
20 void rmtnoteproc(void);
21 void catcher(void*, char*);
22 void usage(void);
23 void writestr(int, char*, char*, int);
24 int readstr(int, char*, int);
25 char *rexcall(int*, char*, char*);
26 int setamalg(char*);
27
28 int notechan;
29 char system[32];
30 int cflag;
31 int hflag;
32 int dbg;
33 char *user;
34
35 char *srvname = "ncpu";
36 char *exportfs = "/bin/exportfs";
37 char *ealgs = "rc4_256 sha1";
38
39 /* message size for exportfs; may be larger so we can do big graphics in CPU window */
40 int msgsize = 8192+IOHDRSZ;
41
42 /* authentication mechanisms */
43 static int netkeyauth(int);
44 static int netkeysrvauth(int, char*);
45 static int p9auth(int);
46 static int srvp9auth(int, char*);
47 static int noauth(int);
48 static int srvnoauth(int, char*);
49
50 typedef struct AuthMethod AuthMethod;
51 struct AuthMethod {
52 char *name; /* name of method */
53 int (*cf)(int); /* client side authentication */
54 int (*sf)(int, char*); /* server side authentication */
55 } authmethod[] =
56 {
57 { "p9", p9auth, srvp9auth,},
58 { "netkey", netkeyauth, netkeysrvauth,},
59 /* { "none", noauth, srvnoauth,}, */
60 { nil, nil}
61 };
62 AuthMethod *am = authmethod; /* default is p9 */
63
64 char *p9authproto = "p9any";
65
66 int setam(char*);
67
68 void
69 usage(void)
70 {
71 fprint(2, "usage: cpu [-h system] [-a authmethod] [-e 'crypt hash'] [-c cmd args ...]\n");
72 exits("usage");
73 }
74 int fdd;
75
76 void
77 main(int argc, char **argv)
78 {
79 char dat[128], buf[128], cmd[128], *p, *err;
80 int fd, ms, kms, data;
81
82 /* see if we should use a larger message size */
83 fd = open("/dev/draw", OREAD);
84 if(fd > 0){
85 ms = iounit(fd);
86 if(ms != 0 && ms < ms+IOHDRSZ)
87 msgsize = ms+IOHDRSZ;
88 close(fd);
89 }
90 kms = kiounit();
91 if(msgsize > kms-IOHDRSZ-100) /* 100 for network packets, etc. */
92 msgsize = kms-IOHDRSZ-100;
93
94 user = getuser();
95 if(user == nil)
96 fatal(1, "can't read user name");
97 ARGBEGIN{
98 case 'a':
99 p = EARGF(usage());
100 if(setam(p) < 0)
101 fatal(0, "unknown auth method %s", p);
102 break;
103 case 'e':
104 ealgs = EARGF(usage());
105 if(*ealgs == 0 || strcmp(ealgs, "clear") == 0)
106 ealgs = nil;
107 break;
108 case 'd':
109 dbg++;
110 break;
111 case 'f':
112 /* ignored but accepted for compatibility */
113 break;
114 case 'O':
115 p9authproto = "p9sk2";
116 remoteside(1); /* From listen */
117 break;
118 case 'R': /* From listen */
119 remoteside(0);
120 break;
121 case 'h':
122 hflag++;
123 p = EARGF(usage());
124 strcpy(system, p);
125 break;
126 case 'c':
127 cflag++;
128 cmd[0] = '!';
129 cmd[1] = '\0';
130 while(p = ARGF()) {
131 strcat(cmd, " ");
132 strcat(cmd, p);
133 }
134 break;
135 case 'o':
136 p9authproto = "p9sk2";
137 srvname = "cpu";
138 break;
139 case 'u':
140 user = EARGF(usage());
141 break;
142 default:
143 usage();
144 }ARGEND;
145
146
147 if(argc != 0)
148 usage();
149
150 if(hflag == 0) {
151 p = getenv("cpu");
152 if(p == 0)
153 fatal(0, "set $cpu");
154 strcpy(system, p);
155 }
156
157 if(err = rexcall(&data, system, srvname))
158 fatal(1, "%s: %s", err, system);
159
160 /* Tell the remote side the command to execute and where our working directory is */
161 if(cflag)
162 writestr(data, cmd, "command", 0);
163 if(getwd(dat, sizeof(dat)) == 0)
164 writestr(data, "NO", "dir", 0);
165 else
166 writestr(data, dat, "dir", 0);
167
168 /* start up a process to pass along notes */
169 lclnoteproc(data);
170
171 /*
172 * Wait for the other end to execute and start our file service
173 * of /mnt/term
174 */
175 if(readstr(data, buf, sizeof(buf)) < 0)
176 fatal(1, "waiting for FS");
177 if(strncmp("FS", buf, 2) != 0) {
178 print("remote cpu: %s", buf);
179 exits(buf);
180 }
181
182 /* Begin serving the gnot namespace */
183 close(0);
184 dup(data, 0);
185 close(data);
186 sprint(buf, "%d", msgsize);
187 if(dbg)
188 execl(exportfs, exportfs, "-dm", buf, 0);
189 else
190 execl(exportfs, exportfs, "-m", buf, 0);
191 fatal(1, "starting exportfs");
192 }
193
194 void
195 fatal(int syserr, char *fmt, ...)
196 {
197 char buf[ERRMAX];
198 va_list arg;
199
200 va_start(arg, fmt);
201 doprint(buf, buf+sizeof(buf), fmt, arg);
202 va_end(arg);
203 if(syserr)
204 fprint(2, "cpu: %s: %r\n", buf);
205 else
206 fprint(2, "cpu: %s\n", buf);
207 exits(buf);
208 }
209
210 char *negstr = "negotiating authentication method";
211
212 char bug[256];
213
214 int
215 old9p(int fd)
216 {
217 int p[2];
218
219 if(pipe(p) < 0)
220 fatal(1, "pipe");
221
222 switch(rfork(RFPROC|RFFDG|RFNAMEG)) {
223 case -1:
224 fatal(1, "rfork srvold9p");
225 case 0:
226 if(fd != 1){
227 dup(fd, 1);
228 close(fd);
229 }
230 if(p[0] != 0){
231 dup(p[0], 0);
232 close(p[0]);
233 }
234 close(p[1]);
235 if(0){
236 fd = open("/sys/log/cpu", OWRITE);
237 if(fd != 2){
238 dup(fd, 2);
239 close(fd);
240 }
241 execl("/bin/srvold9p", "srvold9p", "-ds", 0);
242 } else
243 execl("/bin/srvold9p", "srvold9p", "-s", 0);
244 fatal(1, "exec srvold9p");
245 default:
246 close(fd);
247 close(p[0]);
248 }
249 return p[1];
250 }
251
252 /* Invoked with stdin, stdout and stderr connected to the network connection */
253 void
254 remoteside(int old)
255 {
256 char user[128], home[128], buf[128], xdir[128], cmd[128];
257 int i, n, fd, badchdir, gotcmd;
258
259 fd = 0;
260
261 /* negotiate authentication mechanism */
262 n = readstr(fd, cmd, sizeof(cmd));
263 if(n < 0)
264 fatal(1, "authenticating");
265 if(setamalg(cmd) < 0){
266 writestr(fd, "unsupported auth method", nil, 0);
267 fatal(1, "bad auth method %s", cmd);
268 } else
269 writestr(fd, "", "", 1);
270
271 fd = (*am->sf)(fd, user);
272 if(fd < 0)
273 fatal(1, "srvauth");
274
275 /* Set environment values for the user */
276 putenv("user", user);
277 sprint(home, "/usr/%s", user);
278 putenv("home", home);
279
280 /* Now collect invoking cpu's current directory or possibly a command */
281 gotcmd = 0;
282 if(readstr(fd, xdir, sizeof(xdir)) < 0)
283 fatal(1, "dir/cmd");
284 if(xdir[0] == '!') {
285 strcpy(cmd, &xdir[1]);
286 gotcmd = 1;
287 if(readstr(fd, xdir, sizeof(xdir)) < 0)
288 fatal(1, "dir");
289 }
290
291 /* Establish the new process at the current working directory of the
292 * gnot */
293 badchdir = 0;
294 if(strcmp(xdir, "NO") == 0)
295 chdir(home);
296 else if(chdir(xdir) < 0) {
297 badchdir = 1;
298 chdir(home);
299 }
300
301 /* Start the gnot serving its namespace */
302 writestr(fd, "FS", "FS", 0);
303 writestr(fd, "/", "exportfs dir", 0);
304
305 n = read(fd, buf, sizeof(buf));
306 if(n != 2 || buf[0] != 'O' || buf[1] != 'K')
307 exits("remote tree");
308
309 if(old)
310 fd = old9p(fd);
311
312 /* make sure buffers are big by doing fversion explicitly; pick a huge number; other side will trim */
313 strcpy(buf, VERSION9P);
314 if(fversion(fd, 64*1024, buf, sizeof buf) < 0)
315 exits("fversion failed");
316 if(mount(fd, -1, "/mnt/term", MCREATE|MREPL, "") < 0)
317 exits("mount failed");
318
319 close(fd);
320
321 /* the remote noteproc uses the mount so it must follow it */
322 rmtnoteproc();
323
324 for(i = 0; i < 3; i++)
325 close(i);
326
327 if(open("/mnt/term/dev/cons", OREAD) != 0)
328 exits("open stdin");
329 if(open("/mnt/term/dev/cons", OWRITE) != 1)
330 exits("open stdout");
331 dup(1, 2);
332
333 if(badchdir)
334 print("cpu: failed to chdir to '%s'\n", xdir);
335
336 if(gotcmd)
337 execl("/bin/rc", "rc", "-lc", cmd, 0);
338 else
339 execl("/bin/rc", "rc", "-li", 0);
340 fatal(1, "exec shell");
341 }
342
343 char*
344 rexcall(int *fd, char *host, char *service)
345 {
346 char *na;
347 char dir[128];
348 char err[ERRMAX];
349 char msg[128];
350 int n;
351
352 na = netmkaddr(host, 0, service);
353 if((*fd = dial(na, 0, dir, 0)) < 0)
354 return "can't dial";
355
356 /* negotiate authentication mechanism */
357 if(ealgs != nil)
358 snprint(msg, sizeof(msg), "%s %s", am->name, ealgs);
359 else
360 snprint(msg, sizeof(msg), "%s", am->name);
361 writestr(*fd, msg, negstr, 0);
362 n = readstr(*fd, err, sizeof err);
363 if(n < 0)
364 return negstr;
365 if(*err){
366 werrstr(err);
367 return negstr;
368 }
369
370 /* authenticate */
371 *fd = (*am->cf)(*fd);
372 if(*fd < 0)
373 return "can't authenticate";
374 return 0;
375 }
376
377 void
378 writestr(int fd, char *str, char *thing, int ignore)
379 {
380 int l, n;
381
382 l = strlen(str);
383 n = write(fd, str, l+1);
384 if(!ignore && n < 0)
385 fatal(1, "writing network: %s", thing);
386 }
387
388 int
389 readstr(int fd, char *str, int len)
390 {
391 int n;
392
393 while(len) {
394 n = read(fd, str, 1);
395 if(n < 0)
396 return -1;
397 if(*str == '\0')
398 return 0;
399 str++;
400 len--;
401 }
402 return -1;
403 }
404
405 static int
406 readln(char *buf, int n)
407 {
408 char *p = buf;
409
410 n--;
411 while(n > 0){
412 if(read(0, p, 1) != 1)
413 break;
414 if(*p == '\n' || *p == '\r'){
415 *p = 0;
416 return p-buf;
417 }
418 p++;
419 }
420 *p = 0;
421 return p-buf;
422 }
423
424 /*
425 * user level challenge/response
426 */
427 static int
428 netkeyauth(int fd)
429 {
430 char chall[32];
431 char resp[32];
432
433 strcpy(chall, getuser());
434 print("user[%s]: ", chall);
435 if(readln(resp, sizeof(resp)) < 0)
436 return -1;
437 if(*resp != 0)
438 strcpy(chall, resp);
439 writestr(fd, chall, "challenge/response", 1);
440
441 for(;;){
442 if(readstr(fd, chall, sizeof chall) < 0)
443 break;
444 if(*chall == 0)
445 return fd;
446 print("challenge: %s\nresponse: ", chall);
447 if(readln(resp, sizeof(resp)) < 0)
448 break;
449 writestr(fd, resp, "challenge/response", 1);
450 }
451 return -1;
452 }
453
454 static int
455 netkeysrvauth(int fd, char *user)
456 {
457 char response[32];
458 Chalstate *ch;
459 int tries;
460 AuthInfo *ai;
461
462 if(readstr(fd, user, 32) < 0)
463 return -1;
464
465 ai = nil;
466 ch = nil;
467 for(tries = 0; tries < 10; tries++){
468 if((ch = auth_challenge("p9cr", user, nil)) == nil)
469 return -1;
470 writestr(fd, ch->chal, "challenge", 1);
471 if(readstr(fd, response, sizeof response) < 0)
472 return -1;
473 ch->resp = response;
474 ch->nresp = strlen(response);
475 if((ai = auth_response(ch)) != nil)
476 break;
477 }
478 auth_freechal(ch);
479 if(ai == nil)
480 return -1;
481 writestr(fd, "", "challenge", 1);
482 if(auth_chuid(ai, 0) < 0)
483 fatal(1, "newns");
484 auth_freeAI(ai);
485 return fd;
486 }
487
488 static void
489 mksecret(char *t, uchar *f)
490 {
491 sprint(t, "%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux",
492 f[0], f[1], f[2], f[3], f[4], f[5], f[6], f[7], f[8], f[9]);
493 }
494
495 /*
496 * plan9 authentication followed by rc4 encryption
497 */
498 static int
499 p9auth(int fd)
500 {
501 uchar key[16];
502 uchar digest[SHA1dlen];
503 char fromclientsecret[21];
504 char fromserversecret[21];
505 int i;
506 AuthInfo *ai;
507
508 ai = auth_proxy(fd, auth_getkey, "proto=%q user=%q role=client", p9authproto, user);
509 if(ai == nil)
510 return -1;
511 memmove(key+4, ai->secret, ai->nsecret);
512 if(ealgs == nil)
513 return fd;
514
515 /* exchange random numbers */
516 srand(truerand());
517 for(i = 0; i < 4; i++)
518 key[i] = rand();
519 if(write(fd, key, 4) != 4)
520 return -1;
521 if(readn(fd, key+12, 4) != 4)
522 return -1;
523
524 /* scramble into two secrets */
525 sha1(key, sizeof(key), digest, nil);
526 mksecret(fromclientsecret, digest);
527 mksecret(fromserversecret, digest+10);
528
529 /* set up encryption */
530 i = pushssl(fd, ealgs, fromclientsecret, fromserversecret, nil);
531 if(i < 0)
532 werrstr("can't establish ssl connection: %r");
533 return i;
534 }
535
536 static int
537 noauth(int fd)
538 {
539 ealgs = nil;
540 return fd;
541 }
542
543 static int
544 srvnoauth(int fd, char *user)
545 {
546 strcpy(user, getuser());
547 ealgs = nil;
548 return fd;
549 }
550
551 void
552 loghex(uchar *p, int n)
553 {
554 char buf[100];
555 int i;
556
557 for(i = 0; i < n; i++)
558 sprint(buf+2*i, "%2.2ux", p[i]);
559 syslog(0, "cpu", buf);
560 }
561
562 static int
563 srvp9auth(int fd, char *user)
564 {
565 uchar key[16];
566 uchar digest[SHA1dlen];
567 char fromclientsecret[21];
568 char fromserversecret[21];
569 int i;
570 AuthInfo *ai;
571
572 ai = auth_proxy(0, nil, "proto=%q role=server", p9authproto);
573 if(ai == nil)
574 return -1;
575 if(auth_chuid(ai, nil) < 0)
576 return -1;
577 strcpy(user, ai->cuid);
578 memmove(key+4, ai->secret, ai->nsecret);
579
580 if(ealgs == nil)
581 return fd;
582
583 /* exchange random numbers */
584 srand(truerand());
585 for(i = 0; i < 4; i++)
586 key[i+12] = rand();
587 if(readn(fd, key, 4) != 4)
588 return -1;
589 if(write(fd, key+12, 4) != 4)
590 return -1;
591
592 /* scramble into two secrets */
593 sha1(key, sizeof(key), digest, nil);
594 mksecret(fromclientsecret, digest);
595 mksecret(fromserversecret, digest+10);
596
597 /* set up encryption */
598 i = pushssl(fd, ealgs, fromserversecret, fromclientsecret, nil);
599 if(i < 0)
600 werrstr("can't establish ssl connection: %r");
601 return i;
602 }
603
604 /*
605 * set authentication mechanism
606 */
607 int
608 setam(char *name)
609 {
610 for(am = authmethod; am->name != nil; am++)
611 if(strcmp(am->name, name) == 0)
612 return 0;
613 am = authmethod;
614 return -1;
615 }
616
617 /*
618 * set authentication mechanism and encryption/hash algs
619 */
620 int
621 setamalg(char *s)
622 {
623 ealgs = strchr(s, ' ');
624 if(ealgs != nil)
625 *ealgs++ = 0;
626 return setam(s);
627 }
628
629 char *rmtnotefile = "/mnt/term/dev/cpunote";
630
631 /*
632 * loop reading /mnt/term/dev/note looking for notes.
633 * The child returns to start the shell.
634 */
635 void
636 rmtnoteproc(void)
637 {
638 int n, fd, pid, notepid;
639 char buf[256];
640
641 /* new proc returns to start shell */
642 pid = rfork(RFPROC|RFFDG|RFNOTEG|RFNAMEG|RFMEM);
643 switch(pid){
644 case -1:
645 syslog(0, "cpu", "cpu -R: can't start noteproc: %r");
646 return;
647 case 0:
648 return;
649 }
650
651 /* new proc reads notes from other side and posts them to shell */
652 switch(notepid = rfork(RFPROC|RFFDG|RFMEM)){
653 case -1:
654 syslog(0, "cpu", "cpu -R: can't start wait proc: %r");
655 _exits(0);
656 case 0:
657 fd = open(rmtnotefile, OREAD);
658 if(fd < 0){
659 syslog(0, "cpu", "cpu -R: can't open %s", rmtnotefile);
660 _exits(0);
661 }
662
663 for(;;){
664 n = read(fd, buf, sizeof(buf)-1);
665 if(n <= 0){
666 postnote(PNGROUP, pid, "hangup");
667 _exits(0);
668 }
669 buf[n] = 0;
670 postnote(PNGROUP, pid, buf);
671 }
672 break;
673 }
674
675 /* original proc waits for shell proc to die and kills note proc */
676 for(;;){
677 n = waitpid();
678 if(n < 0 || n == pid)
679 break;
680 }
681 postnote(PNPROC, notepid, "kill");
682 _exits(0);
683 }
684
685 enum
686 {
687 Qdir,
688 Qcpunote,
689
690 Nfid = 32
691 };
692
693 struct {
694 char *name;
695 Qid qid;
696 ulong perm;
697 } fstab[] =
698 {
699 [Qdir] { ".", {Qdir, 0, QTDIR}, DMDIR|0555 },
700 [Qcpunote] { "cpunote", {Qcpunote, 0}, 0444 }
701 };
702
703 typedef struct Note Note;
704 struct Note
705 {
706 Note *next;
707 char msg[ERRMAX];
708 };
709
710 typedef struct Request Request;
711 struct Request
712 {
713 Request *next;
714 Fcall f;
715 };
716
717 typedef struct Fid Fid;
718 struct Fid
719 {
720 int fid;
721 int file;
722 };
723 Fid fids[Nfid];
724
725 struct {
726 Lock;
727 Note *nfirst, *nlast;
728 Request *rfirst, *rlast;
729 } nfs;
730
731 int
732 fsreply(int fd, Fcall *f)
733 {
734 uchar buf[IOHDRSZ+Maxfdata];
735 int n;
736
737 if(dbg)
738 fprint(2, "<-%F\n", f);
739 n = convS2M(f, buf, sizeof buf);
740 if(n > 0){
741 if(write(fd, buf, n) != n){
742 close(fd);
743 return -1;
744 }
745 }
746 return 0;
747 }
748
749 /* match a note read request with a note, reply to the request */
750 int
751 kick(int fd)
752 {
753 Request *rp;
754 Note *np;
755 int rv;
756
757 for(;;){
758 lock(&nfs);
759 rp = nfs.rfirst;
760 np = nfs.nfirst;
761 if(rp == nil || np == nil){
762 unlock(&nfs);
763 break;
764 }
765 nfs.rfirst = rp->next;
766 nfs.nfirst = np->next;
767 unlock(&nfs);
768
769 rp->f.type = Rread;
770 rp->f.count = strlen(np->msg);
771 rp->f.data = np->msg;
772 rv = fsreply(fd, &rp->f);
773 free(rp);
774 free(np);
775 if(rv < 0)
776 return -1;
777 }
778 return 0;
779 }
780
781 void
782 flushreq(int tag)
783 {
784 Request **l, *rp;
785
786 lock(&nfs);
787 for(l = &nfs.rfirst; *l != nil; l = &(*l)->next){
788 rp = *l;
789 if(rp->f.tag == tag){
790 *l = rp->next;
791 unlock(&nfs);
792 free(rp);
793 return;
794 }
795 }
796 unlock(&nfs);
797 }
798
799 Fid*
800 getfid(int fid)
801 {
802 int i, freefid;
803
804 freefid = -1;
805 for(i = 0; i < Nfid; i++){
806 if(freefid < 0 && fids[i].file < 0)
807 freefid = i;
808 if(fids[i].fid == fid)
809 return &fids[i];
810 }
811 if(freefid >= 0){
812 fids[freefid].fid = fid;
813 return &fids[freefid];
814 }
815 return nil;
816 }
817
818 int
819 fsstat(int fd, Fid *fid, Fcall *f)
820 {
821 Dir d;
822 uchar statbuf[256];
823
824 memset(&d, 0, sizeof(d));
825 d.name = fstab[fid->file].name;
826 d.uid = user;
827 d.gid = user;
828 d.muid = user;
829 d.qid = fstab[fid->file].qid;
830 d.mode = fstab[fid->file].perm;
831 d.atime = d.mtime = time(0);
832 f->stat = statbuf;
833 f->nstat = convD2M(&d, statbuf, sizeof statbuf);
834 return fsreply(fd, f);
835 }
836
837 int
838 fsread(int fd, Fid *fid, Fcall *f)
839 {
840 Dir d;
841 uchar buf[256];
842 Request *rp;
843
844 switch(fid->file){
845 default:
846 return -1;
847 case Qdir:
848 if(f->offset == 0 && f->count >0){
849 memset(&d, 0, sizeof(d));
850 d.name = fstab[Qcpunote].name;
851 d.uid = user;
852 d.gid = user;
853 d.muid = user;
854 d.qid = fstab[Qcpunote].qid;
855 d.mode = fstab[Qcpunote].perm;
856 d.atime = d.mtime = time(0);
857 f->count = convD2M(&d, buf, sizeof buf);
858 f->data = (char*)buf;
859 } else
860 f->count = 0;
861 return fsreply(fd, f);
862 case Qcpunote:
863 rp = mallocz(sizeof(*rp), 1);
864 if(rp == nil)
865 return -1;
866 rp->f = *f;
867 lock(&nfs);
868 if(nfs.rfirst == nil)
869 nfs.rfirst = rp;
870 else
871 nfs.rlast->next = rp;
872 nfs.rlast = rp;
873 unlock(&nfs);
874 return kick(fd);;
875 }
876 }
877
878 char Eperm[] = "permission denied";
879 char Enofile[] = "out of files";
880 char Enotdir[] = "not a directory";
881
882 void
883 notefs(int fd)
884 {
885 uchar buf[IOHDRSZ+Maxfdata];
886 int i, j, n;
887 char err[ERRMAX];
888 Fcall f;
889 Fid *fid, *nfid;
890 int doreply;
891
892 rfork(RFNOTEG);
893 fmtinstall('F', fcallconv);
894
895 for(n = 0; n < Nfid; n++)
896 fids[n].file = -1;
897
898 for(;;){
899 n = read9pmsg(fd, buf, sizeof(buf));
900 if(n <= 0){
901 if(dbg)
902 fprint(2, "read9pmsg(%d) returns %d: %r\n", fd, n);
903 break;
904 }
905 if(convM2S(buf, n, &f) < 0)
906 break;
907 if(dbg)
908 fprint(2, "->%F\n", &f);
909 doreply = 1;
910 fid = getfid(f.fid);
911 if(fid == nil){
912 nofids:
913 f.type = Rerror;
914 f.ename = Enofile;
915 fsreply(fd, &f);
916 continue;
917 }
918 switch(f.type++){
919 default:
920 f.type = Rerror;
921 f.ename = "unknown type";
922 break;
923 case Tflush:
924 flushreq(f.oldtag);
925 break;
926 case Tversion:
927 if(f.msize > IOHDRSZ+Maxfdata)
928 f.msize = IOHDRSZ+Maxfdata;
929 break;
930 case Tauth:
931 f.type = Rerror;
932 f.ename = "cpu: authentication not required";
933 break;
934 case Tattach:
935 f.qid = fstab[Qdir].qid;
936 fid->file = Qdir;
937 break;
938 case Twalk:
939 nfid = nil;
940 if(f.newfid != f.fid){
941 nfid = getfid(f.newfid);
942 if(nfid == nil)
943 goto nofids;
944 nfid->file = fid->file;
945 fid = nfid;
946 }
947
948 f.ename = nil;
949 for(i=0; i<f.nwname; i++){
950 if(i > MAXWELEM){
951 f.type = Rerror;
952 f.ename = "too many name elements";
953 break;
954 }
955 if(fid->file != Qdir){
956 f.type = Rerror;
957 f.ename = Enotdir;
958 break;
959 }
960 if(strcmp(f.wname[i], "cpunote") == 0){
961 fid->file = Qcpunote;
962 f.wqid[i] = fstab[Qcpunote].qid;
963 continue;
964 }
965 f.type = Rerror;
966 f.ename = err;
967 strcpy(err, "cpu: file \"");
968 for(j=0; j<=i; j++){
969 if(strlen(err)+1+strlen(f.wname[j])+32 > sizeof err)
970 break;
971 if(j != 0)
972 strcat(err, "/");
973 strcat(err, f.wname[j]);
974 }
975 strcat(err, "\" does not exist");
976 break;
977 }
978 if(nfid != nil && (f.ename != nil || i < f.nwname))
979 nfid ->file = -1;
980 if(f.type != Rerror)
981 f.nwqid = i;
982 break;
983 case Topen:
984 if(f.mode != OREAD){
985 f.type = Rerror;
986 f.ename = Eperm;
987 }
988 f.qid = fstab[fid->file].qid;
989 break;
990 case Tcreate:
991 f.type = Rerror;
992 f.ename = Eperm;
993 break;
994 case Tread:
995 if(fsread(fd, fid, &f) < 0)
996 goto err;
997 doreply = 0;
998 break;
999 case Twrite:
1000 f.type = Rerror;
1001 f.ename = Eperm;
1002 break;
1003 case Tclunk:
1004 fid->file = -1;
1005 break;
1006 case Tremove:
1007 f.type = Rerror;
1008 f.ename = Eperm;
1009 break;
1010 case Tstat:
1011 if(fsstat(fd, fid, &f) < 0)
1012 goto err;
1013 doreply = 0;
1014 break;
1015 case Twstat:
1016 f.type = Rerror;
1017 f.ename = Eperm;
1018 break;
1019 }
1020 if(doreply)
1021 if(fsreply(fd, &f) < 0)
1022 break;
1023 }
1024 err:
1025 if(dbg)
1026 fprint(2, "notefs exiting: %r\n");
1027 close(fd);
1028 }
1029
1030 char notebuf[ERRMAX];
1031
1032 void
1033 catcher(void*, char *text)
1034 {
1035 int n;
1036
1037 n = strlen(text);
1038 if(n >= sizeof(notebuf))
1039 n = sizeof(notebuf)-1;
1040 memmove(notebuf, text, n);
1041 notebuf[n] = '\0';
1042 noted(NCONT);
1043 }
1044
1045 /*
1046 * mount in /dev a note file for the remote side to read.
1047 */
1048 void
1049 lclnoteproc(int netfd)
1050 {
1051 int exportfspid;
1052 Waitmsg *w;
1053 Note *np;
1054 int pfd[2];
1055
1056 if(pipe(pfd) < 0){
1057 fprint(2, "cpu: can't start note proc: pipe: %r\n");
1058 return;
1059 }
1060
1061 /* new proc mounts and returns to start exportfs */
1062 switch(exportfspid = rfork(RFPROC|RFNAMEG|RFFDG|RFMEM)){
1063 case -1:
1064 fprint(2, "cpu: can't start note proc: rfork: %r\n");
1065 return;
1066 case 0:
1067 close(pfd[0]);
1068 if(mount(pfd[1], -1, "/dev", MBEFORE, "") < 0)
1069 fprint(2, "cpu: can't mount note proc: %r\n");
1070 close(pfd[1]);
1071 return;
1072 }
1073
1074 close(netfd);
1075 close(pfd[1]);
1076
1077 /* new proc listens for note file system rpc's */
1078 switch(rfork(RFPROC|RFNAMEG|RFMEM)){
1079 case -1:
1080 fprint(2, "cpu: can't start note proc: rfork1: %r\n");
1081 _exits(0);
1082 case 0:
1083 notefs(pfd[0]);
1084 _exits(0);
1085 }
1086
1087 /* original proc waits for notes */
1088 notify(catcher);
1089 w = nil;
1090 for(;;) {
1091 *notebuf = 0;
1092 free(w);
1093 w = wait();
1094 if(w == nil) {
1095 if(*notebuf == 0)
1096 break;
1097 np = mallocz(sizeof(Note), 1);
1098 if(np != nil){
1099 strcpy(np->msg, notebuf);
1100 lock(&nfs);
1101 if(nfs.nfirst == nil)
1102 nfs.nfirst = np;
1103 else
1104 nfs.nlast->next = np;
1105 nfs.nlast = np;
1106 unlock(&nfs);
1107 kick(pfd[0]);
1108 }
1109 unlock(&nfs);
1110 } else if(w->pid == exportfspid)
1111 break;
1112 }
1113
1114 if(w == nil)
1115 exits(nil);
1116 exits(w->msg);
1117 }