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root/radiance/ray/src/rt/persist.c
Revision: 2.25
Committed: Sat Jan 3 20:07:31 1998 UTC (26 years, 4 months ago) by gregl
Content type: text/plain
Branch: MAIN
Changes since 2.24: +2 -1 lines
Log Message:
randomize wait period in io_process()

File Contents

# Content
1 /* Copyright (c) 1997 Silicon Graphics, Inc. */
2
3 #ifndef lint
4 static char SCCSid[] = "$SunId$ SGI";
5 #endif
6
7 /*
8 * Routines for persistent rtrace and rpict processes.
9 */
10
11 #include "standard.h"
12 #include "random.h"
13
14 #ifdef F_SETLKW
15 #include "paths.h"
16 #include "selcall.h"
17 #include <signal.h>
18 #include <sys/stat.h>
19
20 #ifndef TIMELIM
21 #define TIMELIM (8*3600) /* time limit for holding pattern */
22 #endif
23
24 extern char *strcpy(), *index();
25
26 extern int headismine; /* boolean true if header belongs to me */
27
28 extern char *progname; /* global program name */
29
30 extern char *errfile; /* global error file name */
31
32 static char *persistfname = NULL; /* persist file name */
33 static int persistfd = -1; /* persist file descriptor */
34
35 static char inpname[TEMPLEN+1], outpname[TEMPLEN+1], errname[TEMPLEN+1];
36
37
38 pfdetach() /* release persist (and header) resources */
39 {
40 if (persistfd >= 0)
41 close(persistfd);
42 persistfd = -1;
43 persistfname = NULL;
44 inpname[0] = '\0';
45 outpname[0] = '\0';
46 errname[0] = '\0';
47 headismine = 0;
48 }
49
50
51 pfclean() /* clean up persist files */
52 {
53 if (persistfd >= 0)
54 close(persistfd);
55 if (persistfname != NULL)
56 unlink(persistfname);
57 if (inpname[0])
58 unlink(inpname);
59 if (outpname[0])
60 unlink(outpname);
61 if (errname[0])
62 unlink(errname);
63 }
64
65
66 pflock(lf) /* place or release exclusive lock on file */
67 int lf;
68 {
69 struct flock fls;
70
71 fls.l_type = lf ? F_WRLCK : F_UNLCK;
72 fls.l_whence = 0;
73 fls.l_start = 0L;
74 fls.l_len = 0L;
75 if (fcntl(persistfd, F_SETLKW, &fls) < 0)
76 error(SYSTEM, "cannot (un)lock persist file");
77 }
78
79
80 persistfile(pfn) /* open persist file and lock it */
81 char *pfn;
82 {
83 persistfd = open(pfn, O_WRONLY|O_CREAT|O_EXCL, 0644);
84 if (persistfd >= 0) {
85 persistfname = pfn;
86 pflock(1);
87 return;
88 }
89 /* file exists -- switch to i/o process */
90 persistfd = open(pfn, O_RDWR);
91 if (persistfd < 0) {
92 sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
93 error(SYSTEM, errmsg);
94 }
95 pflock(1);
96 io_process(); /* never returns */
97 }
98
99
100 static int got_io;
101
102 static int sig_io() { got_io++; }
103
104 static int sig_alrm() { quit(0); }
105
106
107 pfhold() /* holding pattern for idle rendering process */
108 {
109 int (*oldalrm)();
110 char buf[512];
111 register int n;
112 /* close input and output descriptors */
113 close(fileno(stdin));
114 close(fileno(stdout));
115 if (errfile == NULL)
116 close(fileno(stderr));
117 /* create named pipes for input and output */
118 if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
119 goto createrr;
120 if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
121 goto createrr;
122 if (errfile == NULL &&
123 mknod(mktemp(strcpy(errname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
124 goto createrr;
125 sprintf(buf, "%s %d\n%s\n%s\n%s\n", progname, getpid(),
126 inpname, outpname, errname);
127 n = strlen(buf);
128 if (write(persistfd, buf, n) < n)
129 error(SYSTEM, "error writing persist file");
130 lseek(persistfd, 0L, 0);
131 /* wait TIMELIM for someone to signal us */
132 got_io = 0;
133 signal(SIGIO, sig_io);
134 oldalrm = (int (*)())signal(SIGALRM, sig_alrm);
135 alarm(TIMELIM);
136 pflock(0); /* unlock persist file for attach */
137 while (!got_io)
138 pause(); /* wait for attach */
139 alarm(0); /* turn off alarm */
140 signal(SIGALRM, oldalrm);
141 signal(SIGIO, SIG_DFL);
142 pflock(1); /* grab persist file back */
143 /* someone wants us; reopen stdin and stdout */
144 if (freopen(inpname, "r", stdin) == NULL)
145 goto openerr;
146 if (freopen(outpname, "w", stdout) == NULL)
147 goto openerr;
148 sleep(3); /* give them a chance to open their pipes */
149 if (errname[0]) {
150 if (freopen(errname, "w", stderr) == NULL)
151 goto openerr;
152 unlink(errname);
153 errname[0] = '\0';
154 }
155 unlink(inpname);
156 inpname[0] = '\0';
157 unlink(outpname);
158 outpname[0] = '\0';
159 return;
160 createrr:
161 error(SYSTEM, "cannot create named pipes in pfhold");
162 openerr:
163 error(SYSTEM, "cannot open named pipes in pfhold");
164 }
165
166
167 io_process() /* just act as go-between for actual process */
168 {
169 register char *cp;
170 register int nr, n;
171 char buf[BUFSIZ], *pfin, *pfout, *pferr;
172 int pid, nfds;
173 int fdout, fderr = -1;
174 int status = 0;
175 fd_set readfds, excepfds;
176 /* load persist file */
177 n = 40;
178 while ((nr = read(persistfd, buf, sizeof(buf)-1)) == 0) {
179 if (!n--)
180 error(USER, "unattended persist file?");
181 pflock(0);
182 sleep(3+(3*getpid()+random())%13); /* wait until ready */
183 pflock(1);
184 }
185 if (nr < 0)
186 error(SYSTEM, "error reading persist file");
187 ftruncate(persistfd, 0L); /* truncate persist file */
188 pfdetach(); /* close & release persist file */
189 buf[nr] = '\0'; /* parse what we got */
190 if ((cp = index(buf, ' ')) == NULL)
191 goto formerr;
192 *cp++ = '\0';
193 if ((pid = atoi(cp)) <= 0)
194 goto formerr;
195 if ((cp = index(cp, '\n')) == NULL)
196 goto formerr;
197 pfin = ++cp;
198 if ((cp = index(cp, '\n')) == NULL)
199 goto formerr;
200 *cp++ = '\0';
201 pfout = cp;
202 if ((cp = index(cp, '\n')) == NULL)
203 goto formerr;
204 *cp++ = '\0';
205 pferr = cp;
206 if ((cp = index(cp, '\n')) == NULL)
207 goto formerr;
208 *cp++ = '\0';
209 if (cp-buf != nr)
210 goto formerr;
211 if (strcmp(buf, progname)) {
212 sprintf(errmsg, "persist file for %s, not %s", buf, progname);
213 error(USER, errmsg);
214 }
215 /* wake up rendering process */
216 if (kill(pid, SIGIO) < 0)
217 error(SYSTEM, "cannot signal rendering process in io_process");
218 /* fork child feeder process */
219 pid = fork();
220 if (pid < 0)
221 error(SYSTEM, "fork failed in io_process");
222 if (pid == 0) { /* feeder loop */
223 int fdin;
224 close(1); /* open input pipe */
225 if ((fdin = open(pfin, O_WRONLY)) < 0)
226 error(SYSTEM, "cannot open feed pipe in io_process");
227 /* renderer stdin */
228 while ((nr = read(0, cp=buf, sizeof(buf))) > 0) {
229 do {
230 if ((n = write(fdin, cp, nr)) <= 0)
231 goto writerr;
232 cp += n;
233 } while ((nr -= n) > 0);
234 }
235 if (nr < 0)
236 goto readerr;
237 _exit(0);
238 }
239 close(0);
240 /* open output pipes, in order */
241 if ((fdout = open(pfout, O_RDONLY)) < 0)
242 error(SYSTEM, "cannot open output pipe in io_process");
243 if (pferr[0] && (fderr = open(pferr, O_RDONLY)) < 0)
244 error(SYSTEM, "cannot open error pipe in io_process");
245 for ( ; ; ) { /* eater loop */
246 FD_ZERO(&readfds);
247 FD_ZERO(&excepfds);
248 nfds = 0;
249 if (fdout >= 0) {
250 FD_SET(fdout, &readfds);
251 FD_SET(fdout, &excepfds);
252 nfds = fdout+1;
253 }
254 if (fderr >= 0) {
255 FD_SET(fderr, &readfds);
256 FD_SET(fderr, &excepfds);
257 nfds = fderr+1;
258 }
259 if (nfds == 0)
260 break; /* all done, exit */
261 if (select(nfds, &readfds, NULL, &excepfds, NULL) < 0)
262 error(SYSTEM, "error in select call in io_process");
263 /* renderer stderr */
264 if (fderr >= 0 && (FD_ISSET(fderr, &readfds) ||
265 FD_ISSET(fderr, &excepfds))) {
266 nr = read(fderr, cp=buf, sizeof(buf));
267 if (nr < 0)
268 goto readerr;
269 if (nr == 0) {
270 close(fderr);
271 /* close(2); don't close stderr! */
272 fderr = -1;
273 } else {
274 cp[nr] = '\0'; /* deduce status if we can */
275 n = strlen(progname);
276 if (!strncmp(cp, progname, n) &&
277 cp[n++] == ':' &&
278 cp[n++] == ' ') {
279 register struct erract *ep;
280 for (ep = erract; ep < erract+NERRS;
281 ep++)
282 if (ep->pre[0] &&
283 !strncmp(cp+n, ep->pre,
284 strlen(ep->pre))) {
285 status = ep->ec;
286 break;
287 }
288 }
289 do { /* write message */
290 if ((n = write(2, cp, nr)) <= 0)
291 goto writerr;
292 cp += n;
293 } while ((nr -= n) > 0);
294 }
295 }
296 /* renderer stdout */
297 if (fdout >= 0 && (FD_ISSET(fdout, &readfds) ||
298 FD_ISSET(fdout, &excepfds))) {
299 nr = read(fdout, cp=buf, sizeof(buf));
300 if (nr < 0)
301 goto readerr;
302 if (nr == 0) { /* EOF */
303 close(fdout);
304 close(1);
305 fdout = -1;
306 } else
307 do { /* write it all */
308 if ((n = write(1, cp, nr)) <= 0)
309 goto writerr;
310 cp += n;
311 } while ((nr -= n) > 0);
312 }
313 }
314 wait(0); /* wait for feeder process */
315 _exit(status);
316 formerr:
317 error(USER, "format error in persist file");
318 readerr:
319 error(SYSTEM, "read error in io_process");
320 writerr:
321 error(SYSTEM, "write error in io_process");
322 }
323
324 #else
325
326 pfclean() {}
327
328 #endif