1c1a9fa1 |
1 | /* |
2 | * userv service (or standalone program) |
3 | * for per-user IP subranges. |
4 | * |
5 | * This is invoked as root, directly from userv. |
6 | * Its arguments are supposed to be, in order: |
1e963473 |
7 | * <config> |
8 | * Specifies address ranges and gids which own them. |
1c1a9fa1 |
9 | * -- Indicates that the remaining arguments are user-supplied |
10 | * and therefore untrusted. |
11 | * <local-addr>,<peer-addr>,<mtu>,<proto> |
12 | * As for slattach. Supported protocols are slip, cslip, and |
13 | * adaptive. Alternatively, set to `debug' to print debugging |
14 | * info. <local-addr> is address of the interface on chiark; |
15 | * <peer-addr> is the address of the point-to-point peer. |
16 | * <prefix>/<mask>,<prefix>/<mask>,... |
17 | * List of additional routes to add for this interface. |
2ed30784 |
18 | * May be the empty argument, or `-' if this is problematic. |
1c1a9fa1 |
19 | * |
1e963473 |
20 | * <config> is either |
21 | * <gid>,<prefix>/<len>[,<junk>] |
22 | * indicating that that gid may allocate addresses in |
23 | * the relevant subspace (<junk> is ignored) |
24 | * or #... |
25 | * which is a comment |
26 | * or /<config-file-name> or ./<config-file-name> or ../<config-file-name> |
27 | * which refers to a file which contains lines which |
28 | * are each <config> |
29 | * or * |
30 | * which means that anything is permitted |
31 | * |
1c1a9fa1 |
32 | * Should be run from userv with no-disconnect-hup. |
33 | */ |
caa68336 |
34 | /* |
35 | * Copyright (C) 1999 Ian Jackson |
36 | * |
37 | * This is free software; you can redistribute it and/or modify it |
38 | * under the terms of the GNU General Public License as published by |
39 | * the Free Software Foundation; either version 2 of the License, or |
40 | * (at your option) any later version. |
41 | * |
42 | * This program is distributed in the hope that it will be useful, but |
43 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
44 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
45 | * General Public License for more details. |
46 | * |
47 | * You should have received a copy of the GNU General Public License |
48 | * along with userv-utils; if not, write to the Free Software |
49 | * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
50 | * |
51 | * $Id$ |
52 | */ |
1c1a9fa1 |
53 | |
54 | #include <stdio.h> |
55 | #include <string.h> |
56 | #include <stdlib.h> |
57 | #include <assert.h> |
58 | #include <errno.h> |
1e963473 |
59 | #include <stdarg.h> |
60 | #include <ctype.h> |
61 | #include <limits.h> |
02b2392d |
62 | #include <signal.h> |
63 | #include <unistd.h> |
64 | |
65 | #include <sys/types.h> |
66 | #include <sys/wait.h> |
67 | #include <sys/stat.h> |
1c1a9fa1 |
68 | |
1e963473 |
69 | #define NARGS 4 |
1c1a9fa1 |
70 | #define MAXEXROUTES 5 |
a48a8f0d |
71 | #define ATXTLEN 16 |
1c1a9fa1 |
72 | |
1e963473 |
73 | static const unsigned long gidmaxval= (unsigned long)((gid_t)-2); |
74 | static const char *const protos_ok[]= { "slip", "cslip", "adaptive", 0 }; |
02b2392d |
75 | static const int signals[]= { SIGHUP, SIGINT, SIGTERM, 0 }; |
1e963473 |
76 | |
77 | static const char *configstr, *proto; |
1c1a9fa1 |
78 | static unsigned long localaddr, peeraddr, mtu; |
1e963473 |
79 | static int localallow, peerallow, allallow; |
1c1a9fa1 |
80 | static int nexroutes; |
81 | static struct exroute { |
82 | unsigned long prefix, mask; |
1e963473 |
83 | int allow; |
1c1a9fa1 |
84 | char prefixtxt[ATXTLEN], masktxt[ATXTLEN]; |
85 | } exroutes[MAXEXROUTES]; |
86 | |
1e963473 |
87 | static char localtxt[ATXTLEN]; |
88 | static char peertxt[ATXTLEN]; |
89 | |
90 | static struct pplace { |
91 | struct pplace *parent; |
92 | const char *filename; |
93 | int lineno; |
94 | } *cpplace; |
95 | |
02b2392d |
96 | |
6d360a53 |
97 | static int slpipe[2], ptmaster, undoslattach; |
02b2392d |
98 | static const char *ifname; |
99 | static const char *ptyname; |
100 | |
101 | #define NPIDS 4 |
102 | |
103 | static union { |
104 | struct { pid_t sl, cout, cin, task; } byname; |
105 | pid_t bynumber[NPIDS]; |
106 | } pids; |
107 | sigset_t emptyset, fullset; |
108 | |
109 | |
6d360a53 |
110 | static int cleantask(void) { |
111 | pid_t pid; |
112 | |
113 | pid= fork(); |
114 | if (!pid) return 1; |
115 | if (pid == (pid_t)-1) |
116 | perror("userv-ipif: fork for undo slattach failed - cannot clean up properly"); |
117 | return 0; |
118 | } |
119 | |
02b2392d |
120 | static void terminate(int estatus) { |
121 | int i, status; |
122 | pid_t pid; |
123 | |
124 | for (i=0; i<NPIDS; i++) |
125 | if (pids.bynumber[i]) kill(pids.bynumber[i], SIGTERM); |
6d360a53 |
126 | |
127 | if (undoslattach) { |
128 | if (cleantask()) { |
129 | execlp("slattach", "slattach", "-p", "tty", ptyname, (char*)0); |
130 | perror("userv-ipif: exec slattach for undo slattach failed"); |
131 | exit(-1); |
132 | } |
133 | if (ifname && cleantask()) { |
134 | execlp("ifconfig", "ifconfig", ifname, "down", (char*)0); |
135 | perror("userv-ipif: exec ifconfig for undo ifconfig failed"); |
136 | exit(-1); |
137 | } |
138 | } |
139 | |
02b2392d |
140 | for (;;) { |
141 | pid= waitpid(-1,&status,0); |
142 | if (pid == (pid_t)-1) break; |
143 | } |
144 | exit(estatus); |
145 | } |
146 | |
147 | |
1e963473 |
148 | static void fatal(const char *fmt, ...) |
149 | __attribute__((format(printf,1,2))); |
150 | static void fatal(const char *fmt, ...) { |
151 | va_list al; |
152 | va_start(al,fmt); |
1c1a9fa1 |
153 | |
1e963473 |
154 | fputs("userv-ipif service: fatal error: ",stderr); |
155 | vfprintf(stderr, fmt, al); |
156 | putc('\n',stderr); |
02b2392d |
157 | terminate(8); |
1c1a9fa1 |
158 | } |
159 | |
1e963473 |
160 | static void sysfatal(const char *fmt, ...) |
161 | __attribute__((format(printf,1,2))); |
162 | static void sysfatal(const char *fmt, ...) { |
163 | va_list al; |
164 | int e; |
165 | |
166 | e= errno; |
167 | va_start(al,fmt); |
168 | |
6d360a53 |
169 | fputs("userv-ipif service: fatal system error: ",stderr); |
1e963473 |
170 | vfprintf(stderr, fmt, al); |
6d360a53 |
171 | fprintf(stderr,": %s\n", strerror(e)); |
02b2392d |
172 | terminate(12); |
1c1a9fa1 |
173 | } |
1e963473 |
174 | |
175 | |
176 | static void badusage(const char *fmt, ...) |
177 | __attribute__((format(printf,1,2))); |
178 | static void badusage(const char *fmt, ...) { |
179 | va_list al; |
180 | struct pplace *cpp; |
1c1a9fa1 |
181 | |
1e963473 |
182 | if (cpplace) { |
183 | fprintf(stderr, |
184 | "userv-ipif service: %s:%d: ", |
185 | cpplace->filename, cpplace->lineno); |
186 | } else { |
187 | fputs("userv-ipif service: invalid usage: ",stderr); |
188 | } |
189 | va_start(al,fmt); |
190 | vfprintf(stderr, fmt, al); |
191 | putc('\n',stderr); |
192 | |
193 | if (cpplace) { |
194 | for (cpp=cpplace->parent; cpp; cpp=cpp->parent) { |
195 | fprintf(stderr, |
196 | "userv-ipif service: %s:%d: ... in file included from here\n", |
197 | cpp->filename, cpp->lineno); |
198 | } |
199 | } |
02b2392d |
200 | terminate(16); |
1c1a9fa1 |
201 | } |
202 | |
203 | static char *ip2txt(unsigned long addr, char *buf) { |
204 | sprintf(buf, "%lu.%lu.%lu.%lu", |
205 | (addr>>24) & 0x0ff, |
206 | (addr>>16) & 0x0ff, |
207 | (addr>>8) & 0x0ff, |
208 | (addr) & 0x0ff); |
209 | return buf; |
210 | } |
211 | |
212 | static unsigned long eat_number(const char **argp, const char *what, |
213 | unsigned long min, unsigned long max, |
214 | const char *endchars, int *endchar_r) { |
215 | /* If !endchars then the endchar must be a nul, otherwise it may be |
216 | * a nul (resulting in *argp set to 0) or something else (*argp set |
217 | * to point to after delim, *endchar_r set to delim). |
218 | * *endchar_r may be 0. |
219 | */ |
220 | unsigned long rv; |
221 | char *ep; |
222 | int endchar; |
223 | |
baba1099 |
224 | if (!*argp) { badusage("missing number %s",what); } |
1c1a9fa1 |
225 | rv= strtoul(*argp,&ep,0); |
226 | if ((endchar= *ep)) { |
baba1099 |
227 | if (!endchars) badusage("junk after number %s",what); |
1e963473 |
228 | if (!strchr(endchars,endchar)) |
229 | badusage("invalid character or delimiter `%c' in or after number, %s:" |
baba1099 |
230 | " expected %s (or none?)", endchar,what,endchars); |
1c1a9fa1 |
231 | *argp= ep+1; |
232 | } else { |
233 | *argp= 0; |
234 | } |
235 | if (endchar_r) *endchar_r= endchar; |
1e963473 |
236 | if (rv < min || rv > max) badusage("number %s value %lu out of range %lu..%lu", |
237 | what, rv, min, max); |
1c1a9fa1 |
238 | return rv; |
239 | } |
240 | |
1c1a9fa1 |
241 | static void addrnet_mustdiffer(const char *w1, unsigned long p1, unsigned long m1, |
242 | const char *w2, unsigned long p2, unsigned long m2) { |
243 | unsigned long mask; |
244 | |
245 | mask= m1&m2; |
246 | if ((p1 & mask) != (p2 & mask)) return; |
1e963473 |
247 | badusage("%s %08lx/%08lx overlaps/clashes with %s %08lx/%08lx", |
248 | w1,p1,m1, w2,p2,m2); |
1c1a9fa1 |
249 | } |
250 | |
251 | static unsigned long eat_addr(const char **argp, const char *what, |
1c1a9fa1 |
252 | const char *endchars, int *endchar_r) { |
253 | char whatbuf[100]; |
254 | unsigned long rv; |
255 | int i; |
256 | |
1c1a9fa1 |
257 | for (rv=0, i=0; |
258 | i<4; |
259 | i++) { |
260 | rv <<= 8; |
261 | sprintf(whatbuf,"%s byte #%d",what,i); |
262 | rv |= eat_number(argp,whatbuf, 0,255, i<3 ? "." : endchars, endchar_r); |
263 | } |
264 | |
1c1a9fa1 |
265 | return rv; |
266 | } |
267 | |
268 | static void eat_prefixmask(const char **argp, const char *what, |
1c1a9fa1 |
269 | const char *endchars, int *endchar_r, |
270 | unsigned long *prefix_r, unsigned long *mask_r, int *len_r) { |
271 | /* mask_r and len_r may be 0 */ |
272 | char whatbuf[100]; |
273 | int len; |
274 | unsigned long prefix, mask; |
275 | |
1e963473 |
276 | prefix= eat_addr(argp,what, "/",0); |
1c1a9fa1 |
277 | sprintf(whatbuf,"%s length",what); |
278 | len= eat_number(argp,whatbuf, 0,32, endchars,endchar_r); |
279 | |
280 | mask= (~0UL << (32-len)); |
baba1099 |
281 | if (prefix & ~mask) badusage("%s prefix %08lx not fully contained in mask %08lx", |
1e963473 |
282 | what,prefix,mask); |
1c1a9fa1 |
283 | *prefix_r= prefix; |
284 | if (mask_r) *mask_r= mask; |
285 | if (len_r) *len_r= len; |
286 | } |
1e963473 |
287 | |
288 | static int addrnet_isin(unsigned long prefix, unsigned long mask, |
289 | unsigned long mprefix, unsigned long mmask) { |
290 | return !(~mask & mmask) && (prefix & mmask) == mprefix; |
291 | } |
1c1a9fa1 |
292 | |
1c1a9fa1 |
293 | |
1e963473 |
294 | static void permit(unsigned long pprefix, unsigned long pmask) { |
295 | int i, any; |
1c1a9fa1 |
296 | |
1e963473 |
297 | assert(!(pprefix & ~pmask)); |
2c310400 |
298 | any= 0; |
1c1a9fa1 |
299 | |
1e963473 |
300 | if (!proto) fputs("permits",stdout); |
301 | if (addrnet_isin(localaddr,~0UL, pprefix,pmask)) { |
302 | if (!proto) fputs(" local-addr",stdout); |
303 | any= localallow= 1; |
304 | } |
305 | if (addrnet_isin(peeraddr,~0UL, pprefix,pmask)) { |
306 | if (!proto) fputs(" peer-addr",stdout); |
307 | any= peerallow= 1; |
308 | } |
309 | for (i=0; i<nexroutes; i++) { |
310 | if (addrnet_isin(exroutes[i].prefix,exroutes[i].mask, pprefix,pmask)) { |
311 | if (!proto) printf(" route#%d",i); |
312 | any= exroutes[i].allow= 1; |
313 | } |
314 | } |
315 | if (!proto) { |
a48a8f0d |
316 | if (!any) fputs(" nothing",stdout); |
1e963473 |
317 | putchar('\n'); |
318 | } |
319 | } |
1c1a9fa1 |
320 | |
1e963473 |
321 | static void pconfig(const char *configstr, int truncated); |
322 | |
323 | static void pfile(const char *filename) { |
324 | FILE *file; |
325 | char buf[PATH_MAX]; |
326 | int l, truncated, c; |
327 | struct pplace npp, *cpp; |
328 | |
329 | for (cpp=cpplace; cpp; cpp=cpp->parent) { |
330 | if (!strcmp(cpp->filename,filename)) |
331 | badusage("recursive configuration file `%s'",filename); |
332 | } |
333 | |
334 | file= fopen(filename,"r"); |
335 | if (!file) |
336 | badusage("cannot open configuration file `%s': %s", filename, strerror(errno)); |
337 | |
338 | if (!proto) printf("config file `%s':\n",filename); |
339 | |
340 | npp.parent= cpplace; |
341 | npp.filename= filename; |
342 | npp.lineno= 0; |
343 | cpplace= &npp; |
344 | |
345 | while (fgets(buf, sizeof(buf), file)) { |
346 | npp.lineno++; |
347 | l= strlen(buf); |
348 | if (!l) continue; |
349 | |
350 | truncated= (buf[l-1] != '\n'); |
351 | while (l>0 && isspace((unsigned char) buf[l-1])) l--; |
352 | if (!l) continue; |
353 | buf[l]= 0; |
354 | |
355 | if (truncated) { |
356 | while ((c= getc(file)) != EOF && c != '\n'); |
357 | if (c == EOF) break; |
358 | } |
359 | |
360 | pconfig(buf,truncated); |
361 | } |
362 | if (ferror(file)) |
363 | badusage("failed while reading configuration file: %s", strerror(errno)); |
364 | |
365 | cpplace= npp.parent; |
366 | } |
367 | |
368 | static void pconfig(const char *configstr, int truncated) { |
369 | unsigned long fgid, tgid, pprefix, pmask; |
370 | int plen; |
371 | char ptxt[ATXTLEN]; |
372 | const char *gidlist; |
373 | |
374 | switch (configstr[0]) { |
375 | case '*': |
376 | if (strcmp(configstr,"*")) badusage("`*' directive must be only thing on line"); |
377 | permit(0UL,0UL); |
378 | return; |
379 | |
380 | case '#': |
381 | return; |
382 | |
383 | case '/': case '.': |
384 | if (truncated) badusage("filename too long (`%.100s...')",configstr); |
385 | pfile(configstr); |
386 | return; |
387 | |
388 | default: |
389 | if (!isdigit((unsigned char)configstr[0])) |
390 | badusage("unknown configuration directive"); |
391 | |
392 | fgid= eat_number(&configstr,"gid", 0,gidmaxval, ",",0); |
393 | eat_prefixmask(&configstr,"permitted-prefix", ",",0, &pprefix,&pmask,&plen); |
394 | if (!configstr && truncated) badusage("gid,prefix/len,... spec too long"); |
395 | |
396 | if (!proto) printf(" %5lu,%s/%d: ", fgid, ip2txt(pprefix,ptxt), plen); |
397 | |
398 | gidlist= getenv("USERV_GID"); |
399 | if (!gidlist) fatal("USERV_GID not set"); |
1c1a9fa1 |
400 | for (;;) { |
1e963473 |
401 | if (!gidlist) { |
402 | if (!proto) printf("no matching gid\n"); |
403 | return; |
1c1a9fa1 |
404 | } |
1e963473 |
405 | tgid= eat_number(&gidlist,"userv-gid", 0,gidmaxval, " ",0); |
406 | if (tgid == fgid) break; |
1c1a9fa1 |
407 | } |
1e963473 |
408 | permit(pprefix,pmask); |
409 | return; |
1c1a9fa1 |
410 | } |
1e963473 |
411 | } |
412 | |
413 | static void checkallow(int allow, const char *what, |
414 | const char *prefixtxt, const char *masktxt) { |
415 | if (allow) return; |
416 | fprintf(stderr,"userv-ipif service: access denied for %s, %s/%s\n", |
417 | what, prefixtxt, masktxt); |
418 | allallow= 0; |
419 | } |
420 | |
421 | static void parseargs(int argc, const char *const *argv) { |
422 | unsigned long routeaddr, routemask; |
423 | const char *carg; |
424 | const char *const *cprotop; |
425 | int i; |
426 | char erwhatbuf[100], erwhatbuf2[100]; |
427 | |
428 | if (argc < NARGS+1) { badusage("too few arguments"); } |
429 | if (argc > NARGS+1) { badusage("too many arguments"); } |
430 | |
431 | configstr= *++argv; |
1c1a9fa1 |
432 | |
433 | carg= *++argv; |
1e963473 |
434 | if (strcmp(carg,"--")) badusage("separator argument `--' not found, got `%s'",carg); |
1c1a9fa1 |
435 | |
1e963473 |
436 | carg= *++argv; |
437 | localaddr= eat_addr(&carg,"local-addr", ",",0); |
438 | peeraddr= eat_addr(&carg,"peer-addr", ",",0); |
1c1a9fa1 |
439 | mtu= eat_number(&carg,"mtu", 576,65536, ",",0); |
1e963473 |
440 | localallow= peerallow= 0; |
1c1a9fa1 |
441 | |
442 | if (!strcmp(carg,"debug")) { |
443 | proto= 0; |
444 | } else { |
445 | for (cprotop= protos_ok; |
446 | (proto= *cprotop) && strcmp(proto,carg); |
447 | cprotop++); |
448 | if (!proto) fatal("invalid protocol"); |
449 | } |
450 | |
451 | addrnet_mustdiffer("local-addr",localaddr,~0UL, "peer-addr",peeraddr,~0UL); |
452 | |
453 | carg= *++argv; |
2ed30784 |
454 | if (strcmp(carg,"-")) { |
455 | for (nexroutes=0; |
456 | carg && *carg; |
457 | nexroutes++) { |
458 | if (nexroutes == MAXEXROUTES) |
459 | fatal("too many extra routes (only %d allowed)",MAXEXROUTES); |
460 | sprintf(erwhatbuf,"route#%d",nexroutes); |
1c1a9fa1 |
461 | |
2ed30784 |
462 | eat_prefixmask(&carg,erwhatbuf, ",",0, &routeaddr,&routemask,0); |
463 | if (routemask == ~0UL) { |
464 | addrnet_mustdiffer(erwhatbuf,routeaddr,routemask, "local-addr",localaddr,~0UL); |
465 | addrnet_mustdiffer(erwhatbuf,routeaddr,routemask, "peer-addr",peeraddr,~0UL); |
466 | } |
467 | for (i=0; i<nexroutes; i++) { |
468 | sprintf(erwhatbuf2,"route#%d",i); |
469 | addrnet_mustdiffer(erwhatbuf,routeaddr,routemask, |
470 | erwhatbuf2,exroutes[i].prefix,exroutes[i].mask); |
471 | } |
472 | exroutes[nexroutes].prefix= routeaddr; |
473 | exroutes[nexroutes].mask= routemask; |
474 | exroutes[nexroutes].allow= 0; |
475 | ip2txt(routeaddr,exroutes[nexroutes].prefixtxt); |
476 | ip2txt(routemask,exroutes[nexroutes].masktxt); |
1c1a9fa1 |
477 | } |
1c1a9fa1 |
478 | } |
2ed30784 |
479 | |
1c1a9fa1 |
480 | ip2txt(localaddr,localtxt); |
481 | ip2txt(peeraddr,peertxt); |
1e963473 |
482 | } |
483 | |
484 | static void checkpermit(void) { |
485 | int i; |
486 | char erwhatbuf[100]; |
1c1a9fa1 |
487 | |
1e963473 |
488 | allallow= 1; |
489 | checkallow(localallow,"local-addr", localtxt,"32"); |
490 | checkallow(peerallow,"peer-addr", peertxt,"32"); |
491 | for (i=0; i<nexroutes; i++) { |
492 | sprintf(erwhatbuf, "route#%d", i); |
493 | checkallow(exroutes[i].allow, erwhatbuf, exroutes[i].prefixtxt, exroutes[i].masktxt); |
494 | } |
495 | if (!allallow) fatal("access denied"); |
496 | } |
497 | |
498 | static void dumpdebug(void) __attribute__((noreturn)); |
499 | static void dumpdebug(void) { |
500 | int i; |
501 | char erwhatbuf[100]; |
502 | |
503 | printf("protocol: debug\n" |
504 | "local: %08lx == %s\n" |
505 | "peer: %08lx == %s\n" |
506 | "mtu: %ld\n" |
507 | "routes: %d\n", |
508 | localaddr, localtxt, |
509 | peeraddr, peertxt, |
510 | mtu, |
511 | nexroutes); |
512 | for (i=0; i<nexroutes; i++) { |
513 | sprintf(erwhatbuf, "route#%d:", i); |
514 | printf("%-9s %08lx/%08lx == %s/%s\n", |
515 | erwhatbuf, |
516 | exroutes[i].prefix, exroutes[i].mask, |
517 | exroutes[i].prefixtxt, exroutes[i].masktxt); |
1c1a9fa1 |
518 | } |
1e963473 |
519 | if (ferror(stdout) || fclose(stdout)) sysfatal("flush stdout"); |
520 | exit(0); |
521 | } |
522 | |
6d360a53 |
523 | |
524 | static void setsigmask(const sigset_t *ss) { |
525 | int r; |
526 | |
527 | r= sigprocmask(SIG_SETMASK, ss, 0); |
528 | if (r) sysfatal("[un]block signals"); |
529 | } |
530 | |
02b2392d |
531 | static void setsignals(void (*handler)(int), struct sigaction *sa, int chldflags) { |
532 | const int *signalp; |
533 | int r, sig; |
534 | |
535 | sa->sa_handler= handler; |
536 | sa->sa_flags= 0; |
537 | for (signalp=signals; (sig=*signalp); signalp++) { |
538 | r= sigaction(sig, sa, 0); if (r) sysfatal("uncatch signal"); |
539 | } |
540 | sa->sa_flags= chldflags; |
541 | r= sigaction(SIGCHLD, sa, 0); if (r) sysfatal("uncatch children"); |
542 | } |
543 | |
02b2392d |
544 | static void infork(void) { |
545 | struct sigaction sa; |
546 | |
547 | memset(&pids,0,sizeof(pids)); |
548 | sigemptyset(&sa.sa_mask); |
549 | setsignals(SIG_DFL,&sa,0); |
550 | setsigmask(&emptyset); |
6d360a53 |
551 | undoslattach= 0; |
02b2392d |
552 | } |
553 | |
554 | static pid_t makesubproc(void (*entry)(void)) { |
555 | pid_t pid; |
556 | |
557 | pid= fork(); if (pid == (pid_t)-1) sysfatal("fork for subprocess"); |
558 | if (pid) return pid; |
559 | |
560 | infork(); |
561 | entry(); |
562 | abort(); |
563 | } |
564 | |
565 | static int task(void) { |
566 | pid_t pid; |
567 | |
568 | pid= fork(); |
6d360a53 |
569 | if (pid == (pid_t)-1) sysfatal("fork for task"); |
570 | if (!pid) { infork(); return 1; } |
02b2392d |
571 | |
572 | pids.byname.task= pid; |
573 | while (pids.byname.task) sigsuspend(&emptyset); |
574 | return 0; |
575 | } |
576 | |
6d360a53 |
577 | static void mdup2(int fd1, int fd2, const char *what) { |
578 | int r; |
579 | |
580 | for (;;) { |
581 | r= dup2(fd1,fd2); if (r==fd2) return; |
582 | if (r!=-1) fatal("dup2 in %s gave wrong answer %d instead of %d",what,r,fd2); |
583 | if (errno != EINTR) sysfatal("dup2 failed in %s",what); |
584 | } |
585 | } |
586 | |
02b2392d |
587 | static void sl_entry(void) { |
6d360a53 |
588 | mdup2(slpipe[1],1,"slattach child"); |
02b2392d |
589 | execlp("slattach", "slattach", "-v", "-L", "-p",proto, ptyname, (char*)0); |
590 | sysfatal("cannot exec slattach"); |
591 | } |
592 | |
593 | static void cin_entry(void) { |
6d360a53 |
594 | mdup2(ptmaster,1,"cat input child"); |
02b2392d |
595 | execlp("cat", "cat", (char*)0); |
596 | sysfatal("cannot exec cat input"); |
597 | } |
598 | |
599 | static void cout_entry(void) { |
6d360a53 |
600 | mdup2(ptmaster,0,"cat output child"); |
02b2392d |
601 | execlp("cat", "cat", (char*)0); |
602 | sysfatal("cannot exec cat output"); |
603 | } |
604 | |
605 | static void sighandler(int signum) { |
606 | pid_t pid; |
607 | int estatus, status; |
608 | const char *taskfail; |
609 | |
610 | estatus= 4; |
611 | |
612 | if (signum == SIGCHLD) { |
613 | for (;;) { |
614 | pid= waitpid(-1,&status,WNOHANG); |
615 | if (!pid || pid == (pid_t)-1) return; |
616 | |
617 | if (pid == pids.byname.task) { |
618 | pids.byname.task= 0; |
619 | if (!status) return; |
620 | taskfail= "task"; |
621 | } else if (pid == pids.byname.cin) { |
622 | pids.byname.cin= 0; |
623 | if (status) { |
624 | taskfail= "input cat"; |
625 | } else { |
626 | taskfail= 0; |
627 | estatus= 0; |
628 | } |
629 | } else if (pid == pids.byname.cout) { |
630 | pids.byname.cout= 0; |
631 | taskfail= "output cat"; |
632 | } else if (pid == pids.byname.sl) { |
633 | pids.byname.sl= 0; |
634 | taskfail= "slattach"; |
635 | } else { |
636 | continue; |
637 | } |
6d360a53 |
638 | break; |
02b2392d |
639 | } |
640 | if (taskfail) { |
6d360a53 |
641 | if (WIFEXITED(status)) { |
642 | fprintf(stderr, |
643 | "userv-ipif service: %s unexpectedly exited with exit status %d\n", |
644 | taskfail, WEXITSTATUS(status)); |
645 | } else if (WIFSIGNALED(status)) { |
646 | fprintf(stderr, |
647 | "userv-ipif service: %s unexpectedly killed by signal %s%s\n", |
648 | taskfail, strsignal(WTERMSIG(status)), |
649 | WCOREDUMP(status) ? " (core dumped)" : ""); |
650 | } else { |
651 | fprintf(stderr, "userv-ipif service: %s unexpectedly terminated" |
652 | " with unknown status code %d\n", taskfail, status); |
653 | } |
02b2392d |
654 | } |
655 | } else { |
656 | fprintf(stderr, |
657 | "userv-ipif service: received signal %d, terminating\n", |
658 | signum); |
659 | } |
660 | |
661 | terminate(estatus); |
662 | } |
663 | |
664 | static void startup(void) { |
665 | int r; |
666 | struct sigaction sa; |
667 | |
668 | sigfillset(&fullset); |
669 | sigemptyset(&emptyset); |
670 | |
671 | ptmaster= getpt(); if (ptmaster==-1) sysfatal("allocate pty master"); |
672 | r= grantpt(ptmaster); if (r) sysfatal("grab/grant pty slave"); |
673 | ptyname= ptsname(ptmaster); if (!ptyname) sysfatal("get pty slave name"); |
674 | r= chmod(ptyname,0600); if (r) sysfatal("chmod pty slave"); |
6d360a53 |
675 | r= unlockpt(ptmaster); if (r) sysfatal("unlock pty"); |
02b2392d |
676 | |
677 | sigfillset(&sa.sa_mask); |
678 | setsignals(sighandler,&sa,SA_NOCLDSTOP); |
679 | setsigmask(&fullset); |
680 | } |
681 | |
682 | static void startslattach(void) { |
6d360a53 |
683 | static char ifnbuf[200]; |
684 | |
02b2392d |
685 | FILE *piper; |
02b2392d |
686 | int r, l, k; |
687 | |
688 | r= pipe(slpipe); if (r) sysfatal("create pipe"); |
689 | piper= fdopen(slpipe[0],"r"); if (!piper) sysfatal("fdopen pipe"); |
690 | |
6d360a53 |
691 | undoslattach= 1; |
02b2392d |
692 | pids.byname.sl= makesubproc(sl_entry); |
693 | |
694 | close(slpipe[1]); |
695 | setsigmask(&emptyset); |
696 | if (!fgets(ifnbuf,sizeof(ifnbuf),piper)) { |
697 | if (ferror(piper)) sysfatal("cannot read ifname from slattach"); |
698 | else fatal("cannot read ifname from slattach"); |
699 | } |
700 | setsigmask(&fullset); |
701 | l= strlen(ifnbuf); |
2c310400 |
702 | if (l<=0 || ifnbuf[l-1] != '\n') fatal("slattach gave strange output `%s'",ifnbuf); |
02b2392d |
703 | ifnbuf[l-1]= 0; |
704 | for (k=l; k>0 && ifnbuf[k-1]!=' '; k--); |
705 | ifname= ifnbuf+k; |
706 | } |
707 | |
708 | static void netconfigure(void) { |
709 | char mtutxt[100]; |
710 | int i; |
711 | |
712 | if (task()) { |
713 | sprintf(mtutxt,"%lu",mtu); |
714 | |
715 | execlp("ifconfig", "ifconfig", ifname, localtxt, |
716 | "netmask","255.255.255.255", "-broadcast", "pointopoint",peertxt, |
717 | "mtu",mtutxt, "up", (char*)0); |
718 | sysfatal("cannot exec ifconfig"); |
719 | } |
720 | |
02b2392d |
721 | for (i=0; i<nexroutes; i++) { |
722 | if (task()) { |
6d360a53 |
723 | execlp("route","route", "add", "-net",exroutes[i].prefixtxt, |
02b2392d |
724 | "netmask",exroutes[i].masktxt, |
725 | "gw",peertxt, "dev",ifname, (char*)0); |
726 | sysfatal("cannot exec route (for route)"); |
727 | } |
728 | } |
729 | } |
730 | |
731 | static void copydata(void) __attribute__((noreturn)); |
5f1c67ff |
732 | static void copydata(void) { |
733 | int r; |
734 | |
02b2392d |
735 | pids.byname.cin= makesubproc(cin_entry); |
5f1c67ff |
736 | for (;;) { |
737 | r= write(1, "\300", 1); if (r==1) break; |
738 | assert(r==-1); if (errno != EINTR) sysfatal("send initial delim to confirm"); |
739 | } |
02b2392d |
740 | pids.byname.cout= makesubproc(cout_entry); |
741 | |
742 | for (;;) sigsuspend(&emptyset); |
743 | } |
744 | |
1e963473 |
745 | int main(int argc, const char *const *argv) { |
746 | parseargs(argc,argv); |
747 | pconfig(configstr,0); |
748 | checkpermit(); |
749 | if (!proto) dumpdebug(); |
750 | |
02b2392d |
751 | startup(); |
752 | startslattach(); |
753 | netconfigure(); |
754 | copydata(); |
1c1a9fa1 |
755 | } |