386BSD 0.1 development
[unix-history] / usr / src / sbin / init / init.c
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4ef48614
WJ
1/*
2 * Copyright (c) 1986, 1987, 1992 Daniel D. Lanciani.
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 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by
16 * Daniel D. Lanciani.
17 * 4. The name of the author may not
18 * be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY Daniel D. Lanciani ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL Daniel D. Lanciani BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34
35#include <sys/types.h>
36#include <sys/errno.h>
37#include <sys/signal.h>
38#include <sys/wait.h>
39#include <setjmp.h>
40#include <ttyent.h>
41#include <unistd.h>
42
43#define NTTY 32 /* max ttys */
44#define NARG 16 /* max args to login/getty */
45
46/* internal flags */
47#define TTY_SEEN 0x8000
48#define TTY_DIFF 0x4000
49#define TTY_LOGIN 0x2000
50
51/* non-standard tty_logout: rerun login/getty with -o switch to clean line */
52#ifndef TTY_LOGOUT
53#define TTY_LOGOUT 0x1000
54#endif
55
56/* non-standard tty_open: open device for login/getty */
57#ifndef TTY_OPEN
58#define TTY_OPEN 0x0800
59#endif
60
61#define isspace(c) ((c) == ' ' || (c) == '\t')
62
63struct ttytab {
64 char *tt_name;
65 char *tt_getty;
66 char *tt_type;
67 int tt_status;
68 int tt_pid;
69} ttytab[NTTY], *ttytabend = ttytab;
70int drain, sflag;
71char arg[128], nam[64], term[64], *env[] = { term, 0 };
72jmp_buf single, reread;
73char *Reboot = "autoboot";
74
75char *newstring(), *malloc();
76extern int errno;
77
78/* signal state of child process */
79#define SIGNALSFORCHILD \
80 signal(SIGHUP, SIG_DFL); signal(SIGINT, SIG_DFL); \
81 signal(SIGTERM, SIG_DFL); signal(SIGALRM, SIG_DFL); \
82 signal(SIGTSTP, SIG_DFL); signal(SIGCHLD, SIG_DFL); \
83 signal(SIGTTIN, SIG_DFL); signal(SIGTTOU, SIG_DFL);
84
85/* SIGHUP: reread /etc/ttys */
86void
87shup(sig)
88{
89 longjmp(reread, 1);
90}
91
92/* SIGALRM: abort wait and go single user */
93void
94salrm(sig)
95{
96 signal(SIGALRM, SIG_DFL);
97 warn("process hung");
98 longjmp(single, 1);
99}
100
101/* SIGTERM: go single user */
102void
103sterm(sig)
104{
105 register struct ttytab *tt;
106
107 if (!Reboot) {
108 for(tt = ttytab; tt < ttytabend; tt++) {
109 free(tt->tt_name);
110 free(tt->tt_getty);
111 free(tt->tt_type);
112 }
113 ttytabend = ttytab;
114 kill(-1, SIGKILL);
115 kill(-1, SIGCONT);
116 signal(SIGALRM, salrm);
117 alarm(30);
118 while(wait((int *)0) > 0);
119 alarm(0);
120 signal(SIGALRM, SIG_DFL);
121 longjmp(single, 1);
122 }
123}
124
125/* SIGTSTP: drain system */
126void
127ststp(sig)
128{
129 drain = 1;
130}
131
132/* init [-s] [-f] */
133
134main(argc, argv)
135char **argv;
136{
137 register int pid;
138 register struct ttytab *tt;
139 struct ttyent *ty;
140 int status;
141 long mask = sigblock(sigmask(SIGHUP) | sigmask(SIGTERM));
142
143 /* did some idiot try to run us? */
144 if(getpid() != 1) {
145 writes(2,"init: sorry, system daemon, runnable only by system\n");
146 exit(0xff);
147 }
148
149 /* allocate a session for init */
150 (void) setsid();
151
152 /* protect against signals, listen for outside requests */
153 signal(SIGHUP, shup);
154 signal(SIGTSTP, ststp);
155
156 signal (SIGTTIN, SIG_IGN);
157 signal (SIGTTOU, SIG_IGN);
158 signal (SIGCHLD, SIG_IGN);
159 signal (SIGINT, SIG_IGN);
160
161 /* handle arguments, if any */
162 if(argc > 1)
163 if(!strcmp(argv[1], "-s"))
164 sflag++;
165 else if(!strcmp(argv[1], "-f"))
166 Reboot = 0;
167top:
168 /* Single user mode? */
169 if(sflag) {
170 sflag = 0;
171 status = 1;
172 } else {
173 /* otherwise, execute /etc/rc */
174 if (access("/etc/rc", F_OK) == 0) {
175
176 signal(SIGTERM, SIG_IGN); /* XXX */
177 if((pid = fork()) < 0)
178 fatal("fork");
179 else if(!pid) {
180 /* signals, to default state */
181 SIGNALSFORCHILD;
182
183 /* clean off console */
184 revoke("/dev/console");
185
186 /* create a shell */
187 login_tty(open("/dev/console", 2));
188 execl("/bin/sh", "sh", "/etc/rc", Reboot, (char *)0);
189 _exit(127);
190 }
191 while(wait(&status) != pid);
192
193 /* if we are about to be rebooted, then wait for it */
194 if (WIFSIGNALED(status) && WTERMSIG(status) == SIGKILL)
195 pause();
196 } else { status = 1; sflag = 1; goto top; }
197 }
198 signal(SIGTERM, sterm);
199 Reboot = 0;
200
201 /* do single user shell on console */
202 if (setjmp(single) || status) {
203 if((pid = fork()) < 0)
204 fatal("fork");
205 else if(!pid) {
206 /* signals, to default state */
207 SIGNALSFORCHILD;
208
209 /* clean off console */
210 revoke("/dev/console");
211
212 /* do open and configuration of console */
213 login_tty(open("/dev/console", 2));
214 execl("/bin/sh", "-", (char *)0);
215 _exit(127);
216 }
217 while(wait(&status) != pid)
218 goto top;
219 }
220
221 /* multiuser mode, traipse through table */
222 setttyent();
223 for(tt = ttytab; (ty = getttyent()) && tt < &ttytab[NTTY]; tt++) {
224 tt->tt_name = newstring(ty->ty_name);
225 tt->tt_getty = newstring(ty->ty_getty);
226 tt->tt_type = newstring(ty->ty_type);
227 tt->tt_status = ty->ty_status;
228 }
229 ttytabend = tt;
230 endttyent();
231 for(tt = ttytab; tt < ttytabend; getty(tt++));
232
233 /* if we receive a request to reread the table, come here */
234 if(setjmp(reread)) {
235
236 /* first pass. find and clean the entries that have changed */
237 setttyent();
238 while(ty = getttyent()) {
239 for(tt = ttytab; tt < ttytabend; tt++)
240 if(!strcmp(tt->tt_name, ty->ty_name)) {
241 /* if a process present, mark */
242 if((tt->tt_status & ~TTY_LOGIN) !=ty->ty_status)
243 tt->tt_status = ty->ty_status |TTY_DIFF;
244 if(strcmp(tt->tt_getty, ty->ty_getty)) {
245 free(tt->tt_getty);
246 tt->tt_getty = newstring(ty->ty_getty);
247 tt->tt_status |= TTY_DIFF;
248 }
249 if(strcmp(tt->tt_type, ty->ty_type)) {
250 free(tt->tt_type);
251 tt->tt_type = newstring(ty->ty_type);
252 tt->tt_status |= TTY_DIFF;
253 }
254 if(((tt->tt_status |= TTY_SEEN) & TTY_DIFF)
255 && tt->tt_pid > 1)
256 kill(tt->tt_pid, 9);
257 break;
258 }
259 if(tt == ttytabend && tt < &ttytab[NTTY]) {
260 tt->tt_name = newstring(ty->ty_name);
261 tt->tt_getty = newstring(ty->ty_getty);
262 tt->tt_type = newstring(ty->ty_type);
263 tt->tt_status = ty->ty_status |
264 TTY_SEEN | TTY_DIFF;
265 ttytabend++;
266 }
267 }
268 endttyent();
269 /* second pass. offer gettys on previously cleaned entries,
270 and garbage collect "dead" entries */
271 for(tt = ttytab; tt < ttytabend; tt++)
272 if(tt->tt_status & TTY_SEEN) {
273 tt->tt_status &= ~TTY_SEEN;
274 if(tt->tt_status & TTY_DIFF) {
275 tt->tt_status &= ~TTY_DIFF;
276 getty(tt);
277 }
278 }
279 else {
280 if(tt->tt_pid > 1)
281 kill(tt->tt_pid, 9);
282 free(tt->tt_name);
283 free(tt->tt_getty);
284 free(tt->tt_type);
285 pid = tt - ttytab;
286 for(tt++; tt < ttytabend; tt++)
287 tt[-1] = *tt;
288 ttytabend--;
289 tt = &ttytab[pid];
290 }
291 }
292 drain = 0;
293
294 /* listen for terminating gettys and sessions, and process them */
295 while(1) {
296 sigsetmask(mask);
297 pid = wait(&status);
298 sigblock(sigmask(SIGHUP) | sigmask(SIGTERM));
299 if(pid < 0) {
300 sleep(5);
301 continue;
302 }
303 for(tt = ttytab; tt < ttytabend; tt++)
304 if(pid == tt->tt_pid) {
305 if(drain && !(tt->tt_status & TTY_LOGIN)) {
306 free(tt->tt_name);
307 free(tt->tt_getty);
308 free(tt->tt_type);
309 for(tt++; tt < ttytabend; tt++)
310 tt[-1] = *tt;
311 ttytabend--;
312 }
313 else
314 getty(tt);
315 break;
316 }
317 }
318}
319
320/* process a getty for a "line". N.B. by having getty do open, init
321 is not limited by filedescriptors for number of possible users */
322getty(tt)
323struct ttytab *tt;
324{
325 char *sargv[NARG];
326 register char *p = arg, **sp = sargv;
327
328 if(!(tt->tt_status & TTY_ON)) {
329 tt->tt_pid = -1;
330 return;
331 }
332 if((tt->tt_pid = fork()) < 0)
333 fatal("getty fork");
334 else if(tt->tt_pid) {
335 if(tt->tt_status & TTY_LOGOUT)
336 tt->tt_status ^= TTY_LOGIN;
337 return;
338 }
339 signal(SIGHUP, SIG_DFL);
340 signal(SIGTERM, SIG_DFL);
341 signal(SIGTSTP, SIG_DFL);
342 sigsetmask(0);
343 strcpy(p, tt->tt_getty);
344 while(sp < &sargv[NARG - 2]) {
345 while(isspace(*p))
346 p++;
347 if(!*p)
348 break;
349 *sp++ = p;
350 while(!isspace(*p) && *p)
351 p++;
352 if(!*p)
353 break;
354 *p++ = 0;
355 }
356 strcpy(nam, tt->tt_name);
357 *sp++ = nam;
358 *sp = 0;
359 p = *sargv;
360 strcpy(term, "TERM=");
361 strcat(term, tt->tt_type);
362 execve(p, sargv, env);
363bad:
364 sleep(30);
365 fatal(tt->tt_name);
366}
367
368char *
369newstring(s)
370register char *s;
371{
372 register char *n;
373
374 if(!(n = malloc(strlen(s) + 1)))
375 fatal("out of memory");
376 strcpy(n, s);
377 return(n);
378}
379
380warn(s)
381char *s;
382{
383 register int pid;
384 int fd;
385
386 fd = open("/dev/console", 2);
387 writes(fd, "init WARNING: ");
388 writes(fd, s);
389 write(fd, "\n", 1);
390 close(fd);
391}
392
393fatal(s)
394char *s;
395{
396 login_tty(open("/dev/console", 2));
397 writes(2, "init FATAL error: ");
398 perror(s);
399 exit(1);
400 /* panic: init died */
401}
402
403writes(n, s)
404char *s;
405{
406 write(n, s, strlen(s));
407}