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root/radiance/ray/src/rt/persist.c
Revision: 2.36
Committed: Sun Sep 19 07:24:37 2004 UTC (19 years, 6 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad3R6, rad3R6P1
Changes since 2.35: +2 -1 lines
Log Message:
Added explicit kill of feeder process to prevent deadlock (paranoia?)

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: persist.c,v 2.35 2004/09/17 21:43:50 greg Exp $";
3 #endif
4 /*
5 * Routines for persistent rtrace and rpict processes.
6 *
7 * External symbols declared in ray.h
8 */
9
10 #include "copyright.h"
11
12 #include <string.h>
13 #include <signal.h>
14 #include <sys/stat.h>
15
16 #include "platform.h"
17 #include "rtprocess.h" /* getpid() */
18 #include "standard.h"
19 #include "random.h"
20 #include "ray.h"
21
22 #ifdef F_SETLKW
23 #include "paths.h"
24 #include "selcall.h"
25
26 #ifndef TIMELIM
27 #define TIMELIM (8*3600) /* time limit for holding pattern */
28 #endif
29
30 extern int headismine; /* boolean true if header belongs to me */
31 extern char *progname; /* global program name */
32 extern char *errfile; /* global error file name */
33 static char *persistfname = NULL; /* persist file name */
34 static int persistfd = -1; /* persist file descriptor */
35 static char inpname[TEMPLEN+1], outpname[TEMPLEN+1], errname[TEMPLEN+1];
36
37 typedef void (sighandler_t)(int);
38 static sighandler_t sig_io;
39 static sighandler_t sig_alrm;
40
41
42 extern void
43 pfdetach(void) /* release persist (and header) resources */
44 {
45 if (persistfd >= 0)
46 close(persistfd);
47 persistfd = -1;
48 persistfname = NULL;
49 inpname[0] = '\0';
50 outpname[0] = '\0';
51 errname[0] = '\0';
52 headismine = 0;
53 }
54
55
56 extern void
57 pfclean(void) /* clean up persist files */
58 {
59 if (persistfd >= 0)
60 close(persistfd);
61 if (persistfname != NULL)
62 unlink(persistfname);
63 if (inpname[0])
64 unlink(inpname);
65 if (outpname[0])
66 unlink(outpname);
67 if (errname[0])
68 unlink(errname);
69 }
70
71
72 extern void
73 pflock( /* place or release exclusive lock on file */
74 int lf
75 )
76 {
77 struct flock fls;
78
79 fls.l_type = lf ? F_WRLCK : F_UNLCK;
80 fls.l_whence = 0;
81 fls.l_start = 0L;
82 fls.l_len = 0L;
83 if (fcntl(persistfd, F_SETLKW, &fls) < 0)
84 error(SYSTEM, "cannot (un)lock persist file");
85 }
86
87
88 extern void
89 persistfile( /* open persist file and lock it */
90 char *pfn
91 )
92 {
93 persistfd = open(pfn, O_WRONLY|O_CREAT|O_EXCL, 0644);
94 if (persistfd >= 0) {
95 persistfname = pfn;
96 pflock(1);
97 return;
98 }
99 /* file exists -- switch to i/o process */
100 persistfd = open(pfn, O_RDWR);
101 if (persistfd < 0) {
102 sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
103 error(SYSTEM, errmsg);
104 }
105 pflock(1);
106 io_process(); /* never returns */
107 }
108
109
110 static int got_io;
111
112 static void sig_io(int i) { got_io++; }
113
114 static void sig_alrm(int i) { quit(0); }
115
116
117 extern void
118 pfhold(void) /* holding pattern for idle rendering process */
119 {
120 sighandler_t *oldalrm;
121 char buf[512];
122 register int n;
123 /* close input and output descriptors */
124 close(fileno(stdin));
125 close(fileno(stdout));
126 if (errfile == NULL)
127 close(fileno(stderr));
128 /* create named pipes for input and output */
129 if (mkfifo(mktemp(strcpy(inpname,TEMPLATE)), 0600) < 0)
130 goto createrr;
131 if (mkfifo(mktemp(strcpy(outpname,TEMPLATE)), 0600) < 0)
132 goto createrr;
133 if (errfile == NULL &&
134 mkfifo(mktemp(strcpy(errname,TEMPLATE)), 0600) < 0)
135 goto createrr;
136 sprintf(buf, "%s %d\n%s\n%s\n%s\n", progname, getpid(),
137 inpname, outpname, errname);
138 n = strlen(buf);
139 if (write(persistfd, buf, n) < n)
140 error(SYSTEM, "error writing persist file");
141 lseek(persistfd, (off_t)0, SEEK_SET);
142 /* wait TIMELIM for someone to signal us */
143 got_io = 0;
144 signal(SIGIO, sig_io);
145 oldalrm = signal(SIGALRM, sig_alrm);
146 alarm(TIMELIM);
147 pflock(0); /* unlock persist file for attach */
148 while (!got_io)
149 pause(); /* wait for attach */
150 alarm(0); /* turn off alarm */
151 signal(SIGALRM, oldalrm);
152 signal(SIGIO, SIG_DFL);
153 pflock(1); /* grab persist file back */
154 /* someone wants us; reopen stdin and stdout */
155 /*
156 if (freopen(inpname, "r", stdin) == NULL)
157 goto openerr;
158 if (freopen(outpname, "w", stdout) == NULL)
159 goto openerr;
160 */
161 close(0);
162 if (open(inpname, O_RDONLY) != 0)
163 error(INTERNAL, "unexpected stdin file number");
164 clearerr(stdin);
165 close(1);
166 if (open(outpname, O_WRONLY) != 1)
167 error(INTERNAL, "unexpected stdout file number");
168 sleep(3); /* give them a chance to open their pipes */
169 if (errname[0]) {
170 close(2);
171 if (open(errname, O_WRONLY) != 2)
172 error(INTERNAL, "unexpected stderr file number");
173 unlink(errname);
174 errname[0] = '\0';
175 }
176 unlink(inpname);
177 inpname[0] = '\0';
178 unlink(outpname);
179 outpname[0] = '\0';
180 return;
181 createrr:
182 error(SYSTEM, "cannot create named pipes in pfhold");
183 openerr:
184 error(SYSTEM, "cannot open named pipes in pfhold");
185 }
186
187
188 extern void
189 io_process(void) /* just act as go-between for actual process */
190 {
191 register char *cp;
192 register int nr, n;
193 char buf[BUFSIZ], *pfin, *pfout, *pferr;
194 int pid, nfds;
195 int fdout, fderr = -1;
196 int status = 0;
197 fd_set readfds, excepfds;
198 /* load persist file */
199 n = 40;
200 while ((nr = read(persistfd, buf, sizeof(buf)-1)) == 0) {
201 if (!n--)
202 error(USER, "unattended persist file?");
203 pflock(0);
204 sleep(3+(3*getpid()+random())%13); /* wait until ready */
205 pflock(1);
206 }
207 if (nr < 0)
208 error(SYSTEM, "error reading persist file");
209 #ifndef _WIN32 /* XXX we need a replacement for that one */
210 ftruncate(persistfd, (off_t)0L); /* truncate persist file */
211 #endif
212 pfdetach(); /* close & release persist file */
213 buf[nr] = '\0'; /* parse what we got */
214 if ((cp = strchr(buf, ' ')) == NULL)
215 goto formerr;
216 *cp++ = '\0';
217 if ((pid = atoi(cp)) <= 0)
218 goto formerr;
219 if ((cp = strchr(cp, '\n')) == NULL)
220 goto formerr;
221 pfin = ++cp;
222 if ((cp = strchr(cp, '\n')) == NULL)
223 goto formerr;
224 *cp++ = '\0';
225 pfout = cp;
226 if ((cp = strchr(cp, '\n')) == NULL)
227 goto formerr;
228 *cp++ = '\0';
229 pferr = cp;
230 if ((cp = strchr(cp, '\n')) == NULL)
231 goto formerr;
232 *cp++ = '\0';
233 if (cp-buf != nr)
234 goto formerr;
235 if (strcmp(buf, progname)) {
236 sprintf(errmsg, "persist file for %s, not %s", buf, progname);
237 error(USER, errmsg);
238 }
239 /* wake up rendering process */
240 if (kill(pid, SIGIO) < 0)
241 error(SYSTEM, "cannot signal rendering process in io_process");
242 /* fork child feeder process */
243 pid = fork();
244 if (pid < 0)
245 error(SYSTEM, "fork failed in io_process");
246 if (pid == 0) { /* feeder loop */
247 int fdin;
248 close(1); /* open input pipe */
249 if ((fdin = open(pfin, O_WRONLY)) < 0)
250 error(SYSTEM, "cannot open feed pipe in io_process");
251 /* renderer stdin */
252 while ((nr = read(0, cp=buf, sizeof(buf))) > 0) {
253 do {
254 if ((n = write(fdin, cp, nr)) <= 0)
255 goto writerr;
256 cp += n;
257 } while ((nr -= n) > 0);
258 }
259 if (nr < 0)
260 goto readerr;
261 _exit(0);
262 }
263 close(0);
264 /* open output pipes, in order */
265 if ((fdout = open(pfout, O_RDONLY)) < 0)
266 error(SYSTEM, "cannot open output pipe in io_process");
267 if (pferr[0] && (fderr = open(pferr, O_RDONLY)) < 0)
268 error(SYSTEM, "cannot open error pipe in io_process");
269 for ( ; ; ) { /* eater loop */
270 FD_ZERO(&readfds);
271 FD_ZERO(&excepfds);
272 nfds = 0;
273 if (fdout >= 0) {
274 FD_SET(fdout, &readfds);
275 FD_SET(fdout, &excepfds);
276 nfds = fdout+1;
277 }
278 if (fderr >= 0) {
279 FD_SET(fderr, &readfds);
280 FD_SET(fderr, &excepfds);
281 nfds = fderr+1;
282 }
283 if (nfds == 0)
284 break; /* all done, exit */
285 if (select(nfds, &readfds, NULL, &excepfds, NULL) < 0)
286 error(SYSTEM, "error in select call in io_process");
287 /* renderer stderr */
288 if (fderr >= 0 && (FD_ISSET(fderr, &readfds) ||
289 FD_ISSET(fderr, &excepfds))) {
290 nr = read(fderr, cp=buf, sizeof(buf));
291 if (nr < 0)
292 goto readerr;
293 if (nr == 0) {
294 close(fderr);
295 /* close(2); don't close stderr! */
296 fderr = -1;
297 } else {
298 cp[nr] = '\0'; /* deduce status if we can */
299 n = strlen(progname);
300 if (!strncmp(cp, progname, n) &&
301 cp[n++] == ':' &&
302 cp[n++] == ' ') {
303 register struct erract *ep;
304 for (ep = erract; ep < erract+NERRS;
305 ep++)
306 if (ep->pre[0] &&
307 !strncmp(cp+n, ep->pre,
308 strlen(ep->pre))) {
309 status = ep->ec;
310 break;
311 }
312 }
313 do { /* write message */
314 if ((n = write(2, cp, nr)) <= 0)
315 goto writerr;
316 cp += n;
317 } while ((nr -= n) > 0);
318 }
319 }
320 /* renderer stdout */
321 if (fdout >= 0 && (FD_ISSET(fdout, &readfds) ||
322 FD_ISSET(fdout, &excepfds))) {
323 nr = read(fdout, cp=buf, sizeof(buf));
324 if (nr < 0)
325 goto readerr;
326 if (nr == 0) { /* EOF */
327 close(fdout);
328 close(1);
329 fdout = -1;
330 } else
331 do { /* write it all */
332 if ((n = write(1, cp, nr)) <= 0)
333 goto writerr;
334 cp += n;
335 } while ((nr -= n) > 0);
336 }
337 }
338 kill(pid, SIGTERM); /* no more process to feed, so... */
339 waitpid(pid, 0, 0); /* wait for feeder process */
340 _exit(status);
341 formerr:
342 error(USER, "format error in persist file");
343 readerr:
344 error(SYSTEM, "read error in io_process");
345 writerr:
346 error(SYSTEM, "write error in io_process");
347 }
348
349 #else
350
351 extern void pfclean(void) {}
352
353 #endif