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root/radiance/ray/src/rt/persist.c
Revision: 2.16
Committed: Mon Jul 8 19:46:21 1996 UTC (27 years, 9 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.15: +103 -47 lines
Log Message:
changed io_process() to use select() and a single process

File Contents

# Content
1 /* Copyright (c) 1996 Regents of the University of California */
2
3 #ifndef lint
4 static char SCCSid[] = "$SunId$ LBL";
5 #endif
6
7 /*
8 * Routines for persistent rtrace and rpict processes.
9 */
10
11 #include "standard.h"
12
13 #ifdef F_SETLKW
14 #include "paths.h"
15 #include <signal.h>
16 #include <sys/types.h>
17 #include <sys/stat.h>
18 /* select call compatibility stuff */
19 #ifndef FD_SETSIZE
20 #include <sys/param.h>
21 #define FD_SETSIZE NOFILE /* maximum # select file descriptors */
22 #endif
23 #ifndef FD_SET
24 #ifndef NFDBITS
25 #define NFDBITS (8*sizeof(int)) /* number of bits per fd_mask */
26 #endif
27 #define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
28 #define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
29 #define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
30 #define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
31 #endif
32
33 #ifndef TIMELIM
34 #define TIMELIM (8*3600) /* time limit for holding pattern */
35 #endif
36
37 extern char *strcpy(), *index();
38
39 extern int headismine; /* boolean true if header belongs to me */
40
41 extern char *progname; /* global program name */
42
43 extern char *errfile; /* global error file name */
44
45 static char *persistfname = NULL; /* persist file name */
46 static int persistfd = -1; /* persist file descriptor */
47
48 static char inpname[TEMPLEN+1], outpname[TEMPLEN+1], errname[TEMPLEN+1];
49
50
51 pfdetach() /* release persist (and header) resources */
52 {
53 if (persistfd >= 0)
54 close(persistfd);
55 persistfd = -1;
56 persistfname = NULL;
57 inpname[0] = '\0';
58 outpname[0] = '\0';
59 errname[0] = '\0';
60 headismine = 0;
61 }
62
63
64 pfclean() /* clean up persist files */
65 {
66 if (persistfd >= 0)
67 close(persistfd);
68 if (persistfname != NULL)
69 unlink(persistfname);
70 if (inpname[0])
71 unlink(inpname);
72 if (outpname[0])
73 unlink(outpname);
74 if (errname[0])
75 unlink(errname);
76 }
77
78
79 pflock(lf) /* place or release exclusive lock on file */
80 int lf;
81 {
82 struct flock fls;
83
84 fls.l_type = lf ? F_WRLCK : F_UNLCK;
85 fls.l_whence = 0;
86 fls.l_start = 0L;
87 fls.l_len = 0L;
88 if (fcntl(persistfd, F_SETLKW, &fls) < 0)
89 error(SYSTEM, "cannot (un)lock persist file");
90 }
91
92
93 persistfile(pfn) /* open persist file and lock it */
94 char *pfn;
95 {
96 persistfd = open(pfn, O_WRONLY|O_CREAT|O_EXCL, 0644);
97 if (persistfd >= 0) {
98 persistfname = pfn;
99 pflock(1);
100 return;
101 }
102 /* file exists -- switch to i/o process */
103 persistfd = open(pfn, O_RDWR);
104 if (persistfd < 0) {
105 sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
106 error(SYSTEM, errmsg);
107 }
108 pflock(1);
109 io_process(); /* never returns */
110 }
111
112
113 static int got_io;
114
115 static int sig_io() { got_io++; }
116
117 static int sig_alrm() { quit(0); }
118
119
120 pfhold() /* holding pattern for idle rendering process */
121 {
122 int (*oldalrm)();
123 char buf[512];
124 register int n;
125 /* close input and output descriptors */
126 close(fileno(stdin));
127 close(fileno(stdout));
128 if (errfile == NULL)
129 close(fileno(stderr));
130 /* create named pipes for input and output */
131 if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
132 goto createrr;
133 if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
134 goto createrr;
135 if (errfile == NULL &&
136 mknod(mktemp(strcpy(errname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
137 goto createrr;
138 sprintf(buf, "%s %d\n%s\n%s\n%s\n", progname, getpid(),
139 inpname, outpname, errname);
140 n = strlen(buf);
141 if (write(persistfd, buf, n) < n)
142 error(SYSTEM, "error writing persist file");
143 /* wait TIMELIM for someone to signal us */
144 got_io = 0;
145 signal(SIGIO, sig_io);
146 oldalrm = (int (*)())signal(SIGALRM, sig_alrm);
147 alarm(TIMELIM);
148 pflock(0); /* unlock persist file for attach */
149 while (!got_io)
150 pause(); /* wait for attach */
151 pflock(1); /* grab persist file right back! */
152 alarm(0); /* turn off alarm */
153 signal(SIGALRM, oldalrm);
154 signal(SIGIO, SIG_DFL);
155 if (lseek(persistfd, 0L, 0) < 0 || ftruncate(persistfd, 0L) < 0)
156 error(SYSTEM, "seek/truncate error on persist file");
157 /* someone wants us; reopen stdin and stdout */
158 if (freopen(inpname, "r", stdin) == NULL)
159 goto openerr;
160 if (freopen(outpname, "w", stdout) == NULL)
161 goto openerr;
162 if (errname[0]) {
163 if (freopen(errname, "w", stderr) == NULL)
164 goto openerr;
165 unlink(errname);
166 errname[0] = '\0';
167 }
168 unlink(inpname);
169 inpname[0] = '\0';
170 unlink(outpname);
171 outpname[0] = '\0';
172 return;
173 createrr:
174 error(SYSTEM, "cannot create named pipes in pfhold");
175 openerr:
176 error(SYSTEM, "cannot open named pipes in pfhold");
177 }
178
179
180 io_process() /* just act as go-between for actual process */
181 {
182 register char *cp;
183 register int nr, n;
184 char buf[BUFSIZ], *pfin, *pfout, *pferr;
185 int pid, nfds;
186 int fdin, fdout, fderr = -1;
187 fd_set readfds, writefds, excepfds;
188 /* load persist file */
189 while ((nr = read(persistfd, buf, sizeof(buf)-1)) == 0) {
190 pflock(0);
191 sleep(15); /* wait until ready */
192 pflock(1);
193 }
194 pfdetach(); /* close persist file */
195 if (nr < 0)
196 error(SYSTEM, "error reading persist file");
197 buf[nr] = '\0';
198 if ((cp = index(buf, ' ')) == NULL)
199 goto formerr;
200 *cp++ = '\0';
201 if ((pid = atoi(cp)) <= 0)
202 goto formerr;
203 if ((cp = index(cp, '\n')) == NULL)
204 goto formerr;
205 pfin = ++cp;
206 if ((cp = index(cp, '\n')) == NULL)
207 goto formerr;
208 *cp++ = '\0';
209 pfout = cp;
210 if ((cp = index(cp, '\n')) == NULL)
211 goto formerr;
212 *cp++ = '\0';
213 pferr = cp;
214 if ((cp = index(cp, '\n')) == NULL)
215 goto formerr;
216 *cp++ = '\0';
217 if (cp-buf != nr)
218 goto formerr;
219 if (strcmp(buf, progname)) {
220 sprintf(errmsg, "persist file for %s, not %s", buf, progname);
221 error(USER, errmsg);
222 }
223 /* wake up rendering process */
224 if (kill(pid, SIGIO) < 0)
225 error(SYSTEM, "cannot signal rendering process in io_process");
226 /* open named pipes, in order */
227 if ((fdin = open(pfin, O_WRONLY)) < 0)
228 error(SYSTEM, "cannot open input pipe in io_process");
229 if ((fdout = open(pfout, O_RDONLY)) < 0)
230 error(SYSTEM, "cannot open output pipe in io_process");
231 if (pferr[0] && (fderr = open(pferr, O_RDONLY)) < 0)
232 error(SYSTEM, "cannot open error pipe in io_process");
233 for ( ; ; ) { /* loop on select call */
234 FD_ZERO(&readfds);
235 FD_ZERO(&writefds);
236 FD_ZERO(&excepfds);
237 nfds = 0;
238 if (fdin >= 0) {
239 FD_SET(fdin, &writefds);
240 FD_SET(fdin, &excepfds);
241 nfds = fdin+1;
242 }
243 if (fdout >= 0) {
244 FD_SET(fdout, &readfds);
245 FD_SET(fdout, &excepfds);
246 nfds = fdout+1;
247 }
248 if (fderr >= 0) {
249 FD_SET(fderr, &readfds);
250 FD_SET(fderr, &excepfds);
251 nfds = fderr+1;
252 }
253 if (nfds == 0)
254 break; /* all done, exit */
255 if (select(nfds, &readfds, &writefds, &excepfds, NULL) < 0)
256 error(SYSTEM, "error in select call in io_process");
257 /* renderer stderr */
258 if (fderr >= 0 && (FD_ISSET(fderr, &readfds) ||
259 FD_ISSET(fderr, &excepfds))) {
260 nr = read(fderr, cp=buf, sizeof(buf));
261 if (nr < 0)
262 goto readerr;
263 if (nr == 0) {
264 close(fderr);
265 close(2);
266 fderr = -1;
267 } else
268 do { /* write it all */
269 if ((n = write(2, cp, nr)) <= 0)
270 goto writerr;
271 cp += n;
272 } while ((nr -= n) > 0);
273 }
274 /* renderer stdout */
275 if (fdout >= 0 && (FD_ISSET(fdout, &readfds) ||
276 FD_ISSET(fdout, &excepfds))) {
277 nr = read(fdout, cp=buf, sizeof(buf));
278 if (nr < 0)
279 goto readerr;
280 if (nr == 0) { /* EOF */
281 close(fdout);
282 close(1);
283 fdout = -1;
284 } else
285 do { /* write it all */
286 if ((n = write(1, cp, nr)) <= 0)
287 goto writerr;
288 cp += n;
289 } while ((nr -= n) > 0);
290 }
291 /* renderer stdin */
292 if (fdin >= 0 && (FD_ISSET(fdin, &writefds) ||
293 FD_ISSET(fdin, &excepfds))) {
294 nr = read(0, buf, 512); /* use minimal buffer */
295 if (nr < 0)
296 goto readerr;
297 if (nr == 0) {
298 close(0);
299 close(fdin);
300 fdin = -1;
301 } else if (write(fdin, buf, nr) < nr)
302 goto writerr; /* what else to do? */
303 }
304 }
305 _exit(0); /* we ought to return renderer error status! */
306 formerr:
307 error(USER, "format error in persist file");
308 readerr:
309 error(SYSTEM, "read error in io_process");
310 writerr:
311 error(SYSTEM, "write error in io_process");
312 }
313
314 #else
315
316 pfclean() {}
317
318 #endif