src/rt/persist.c

/* Copyright (c) 1997 Silicon Graphics, Inc. */

#ifndef lint
static char SCCSid[] = "$SunId$ SGI";
#endif

/*
 * Routines for persistent rtrace and rpict processes.
 */

#include "standard.h"
#include "random.h"

#ifdef F_SETLKW
#include "paths.h"
#include "selcall.h"
#include <signal.h>
#include <sys/stat.h>

#ifndef TIMELIM
#define TIMELIM         (8*3600)        /* time limit for holding pattern */
#endif

extern char     *strcpy(), *index();

extern int      headismine;     /* boolean true if header belongs to me */

extern char     *progname;      /* global program name */

extern char     *errfile;       /* global error file name */

static char     *persistfname = NULL;   /* persist file name */
static int      persistfd = -1;         /* persist file descriptor */

static char     inpname[TEMPLEN+1], outpname[TEMPLEN+1], errname[TEMPLEN+1];


pfdetach()              /* release persist (and header) resources */
{
        if (persistfd >= 0)
                close(persistfd);
        persistfd = -1;
        persistfname = NULL;
        inpname[0] = '\0';
        outpname[0] = '\0';
        errname[0] = '\0';
        headismine = 0;
}


pfclean()               /* clean up persist files */
{
        if (persistfd >= 0)
                close(persistfd);
        if (persistfname != NULL)
                unlink(persistfname);
        if (inpname[0])
                unlink(inpname);
        if (outpname[0])
                unlink(outpname);
        if (errname[0])
                unlink(errname);
}


pflock(lf)              /* place or release exclusive lock on file */
int     lf;
{
        struct flock    fls;

        fls.l_type = lf ? F_WRLCK : F_UNLCK;
        fls.l_whence = 0;
        fls.l_start = 0L;
        fls.l_len = 0L;
        if (fcntl(persistfd, F_SETLKW, &fls) < 0)
                error(SYSTEM, "cannot (un)lock persist file");
}


persistfile(pfn)        /* open persist file and lock it */
char    *pfn;
{
        persistfd = open(pfn, O_WRONLY|O_CREAT|O_EXCL, 0644);
        if (persistfd >= 0) {
                persistfname = pfn;
                pflock(1);
                return;
        }
                                /* file exists -- switch to i/o process */
        persistfd = open(pfn, O_RDWR);
        if (persistfd < 0) {
                sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
                error(SYSTEM, errmsg);
        }
        pflock(1);
        io_process();   /* never returns */
}


static int      got_io;

static int sig_io() { got_io++; }

static int sig_alrm() { quit(0); }


pfhold()                /* holding pattern for idle rendering process */
{
        int     (*oldalrm)();
        char    buf[512];
        register int    n;
                                /* close input and output descriptors */
        close(fileno(stdin));
        close(fileno(stdout));
        if (errfile == NULL)
                close(fileno(stderr));
                                /* create named pipes for input and output */
        if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
                goto createrr;
        if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
                goto createrr;
        if (errfile == NULL &&
                mknod(mktemp(strcpy(errname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
                goto createrr;
        sprintf(buf, "%s %d\n%s\n%s\n%s\n", progname, getpid(),
                        inpname, outpname, errname);
        n = strlen(buf);
        if (write(persistfd, buf, n) < n)
                error(SYSTEM, "error writing persist file");
        lseek(persistfd, 0L, 0);
                                /* wait TIMELIM for someone to signal us */
        got_io = 0;
        signal(SIGIO, sig_io);
        oldalrm = (int (*)())signal(SIGALRM, sig_alrm);
        alarm(TIMELIM);
        pflock(0);                      /* unlock persist file for attach */
        while (!got_io)
                pause();                /* wait for attach */
        alarm(0);                       /* turn off alarm */
        signal(SIGALRM, oldalrm);
        signal(SIGIO, SIG_DFL);
        pflock(1);                      /* grab persist file back */
                                /* someone wants us; reopen stdin and stdout */
        if (freopen(inpname, "r", stdin) == NULL)
                goto openerr;
        if (freopen(outpname, "w", stdout) == NULL)
                goto openerr;
        sleep(3);               /* give them a chance to open their pipes */
        if (errname[0]) {
                if (freopen(errname, "w", stderr) == NULL)
                        goto openerr;
                unlink(errname);
                errname[0] = '\0';
        }
        unlink(inpname);
        inpname[0] = '\0';
        unlink(outpname);
        outpname[0] = '\0';
        return;
createrr:
        error(SYSTEM, "cannot create named pipes in pfhold");
openerr:
        error(SYSTEM, "cannot open named pipes in pfhold");
}


io_process()            /* just act as go-between for actual process */
{
        register char   *cp;
        register int    nr, n;
        char    buf[BUFSIZ], *pfin, *pfout, *pferr;
        int     pid, nfds;
        int     fdout, fderr = -1;
        int     status = 0;
        fd_set  readfds, excepfds;
                                        /* load persist file */
        n = 40;
        while ((nr = read(persistfd, buf, sizeof(buf)-1)) == 0) {
                if (!n--)
                        error(USER, "unattended persist file?");
                pflock(0);
                sleep(3+(3*getpid()+random())%13);      /* wait until ready */
                pflock(1);
        }
        if (nr < 0)
                error(SYSTEM, "error reading persist file");
        ftruncate(persistfd, 0L);       /* truncate persist file */
        pfdetach();                     /* close & release persist file */
        buf[nr] = '\0';                 /* parse what we got */
        if ((cp = index(buf, ' ')) == NULL)
                goto formerr;
        *cp++ = '\0';
        if ((pid = atoi(cp)) <= 0)
                goto formerr;
        if ((cp = index(cp, '\n')) == NULL)
                goto formerr;
        pfin = ++cp;
        if ((cp = index(cp, '\n')) == NULL)
                goto formerr;
        *cp++ = '\0';
        pfout = cp;
        if ((cp = index(cp, '\n')) == NULL)
                goto formerr;
        *cp++ = '\0';
        pferr = cp;
        if ((cp = index(cp, '\n')) == NULL)
                goto formerr;
        *cp++ = '\0';
        if (cp-buf != nr)
                goto formerr;
        if (strcmp(buf, progname)) {
                sprintf(errmsg, "persist file for %s, not %s", buf, progname);
                error(USER, errmsg);
        }
                                        /* wake up rendering process */
        if (kill(pid, SIGIO) < 0)
                error(SYSTEM, "cannot signal rendering process in io_process");
                                        /* fork child feeder process */
        pid = fork();
        if (pid < 0)
                error(SYSTEM, "fork failed in io_process");
        if (pid == 0) {                 /* feeder loop */
                int     fdin;
                close(1);               /* open input pipe */
                if ((fdin = open(pfin, O_WRONLY)) < 0)
                        error(SYSTEM, "cannot open feed pipe in io_process");
                                                /* renderer stdin */
                while ((nr = read(0, cp=buf, sizeof(buf))) > 0) {
                        do {
                                if ((n = write(fdin, cp, nr)) <= 0)
                                        goto writerr;
                                cp += n;
                        } while ((nr -= n) > 0);
                }
                if (nr < 0)
                        goto readerr;
                _exit(0);
        }
        close(0);
                                        /* open output pipes, in order */
        if ((fdout = open(pfout, O_RDONLY)) < 0)
                error(SYSTEM, "cannot open output pipe in io_process");
        if (pferr[0] && (fderr = open(pferr, O_RDONLY)) < 0)
                error(SYSTEM, "cannot open error pipe in io_process");
        for ( ; ; ) {                   /* eater loop */
                FD_ZERO(&readfds);
                FD_ZERO(&excepfds);
                nfds = 0;
                if (fdout >= 0) {
                        FD_SET(fdout, &readfds);
                        FD_SET(fdout, &excepfds);
                        nfds = fdout+1;
                }
                if (fderr >= 0) {
                        FD_SET(fderr, &readfds);
                        FD_SET(fderr, &excepfds);
                        nfds = fderr+1;
                }
                if (nfds == 0)
                        break;                  /* all done, exit */
                if (select(nfds, &readfds, NULL, &excepfds, NULL) < 0)
                        error(SYSTEM, "error in select call in io_process");
                                                /* renderer stderr */
                if (fderr >= 0 && (FD_ISSET(fderr, &readfds) ||
                                FD_ISSET(fderr, &excepfds))) {
                        nr = read(fderr, cp=buf, sizeof(buf));
                        if (nr < 0)
                                goto readerr;
                        if (nr == 0) {
                                close(fderr);
                                /* close(2);    don't close stderr! */
                                fderr = -1;
                        } else {
                                cp[nr] = '\0';  /* deduce status if we can */
                                n = strlen(progname);
                                if (!strncmp(cp, progname, n) &&
                                                cp[n++] == ':' &&
                                                cp[n++] == ' ') {
                                        register struct erract  *ep;
                                        for (ep = erract; ep < erract+NERRS;
                                                        ep++)
                                                if (ep->pre[0] &&
                                                        !strncmp(cp+n, ep->pre,
                                                            strlen(ep->pre))) {
                                                        status = ep->ec;
                                                        break;
                                                }
                                }
                                do {            /* write message */
                                        if ((n = write(2, cp, nr)) <= 0)
                                                goto writerr;
                                        cp += n;
                                } while ((nr -= n) > 0);
                        }
                }
                                                /* renderer stdout */
                if (fdout >= 0 && (FD_ISSET(fdout, &readfds) ||
                                FD_ISSET(fdout, &excepfds))) {
                        nr = read(fdout, cp=buf, sizeof(buf));
                        if (nr < 0)
                                goto readerr;
                        if (nr == 0) {          /* EOF */
                                close(fdout);
                                close(1);
                                fdout = -1;
                        } else
                                do {            /* write it all */
                                        if ((n = write(1, cp, nr)) <= 0)
                                                goto writerr;
                                        cp += n;
                                } while ((nr -= n) > 0);
                }
        }
        wait(0);                /* wait for feeder process */
        _exit(status);
formerr:
        error(USER, "format error in persist file");
readerr:
        error(SYSTEM, "read error in io_process");
writerr:
        error(SYSTEM, "write error in io_process");
}

#else

pfclean() {}

#endif
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()
#	User	Rev	Content
1	gregl	2.24	/* Copyright (c) 1997 Silicon Graphics, Inc. */
2	greg	2.1
3			#ifndef lint
4	gregl	2.24	static char SCCSid[] = "$SunId$ SGI";
5	greg	2.1	#endif
6
7			/*
8			* Routines for persistent rtrace and rpict processes.
9			*/
10
11			#include "standard.h"
12	gregl	2.25	#include "random.h"
13	greg	2.6
14			#ifdef F_SETLKW
15	greg	2.1	#include "paths.h"
16	gregl	2.21	#include "selcall.h"
17	greg	2.1	#include <signal.h>
18			#include <sys/stat.h>
19
20	greg	2.2	#ifndef TIMELIM
21			#define TIMELIM (83600) / time limit for holding pattern */
22			#endif
23
24	greg	2.1	extern char strcpy(), index();
25
26			extern int headismine; /* boolean true if header belongs to me */
27
28	greg	2.12	extern char progname; / global program name */
29
30	greg	2.14	extern char errfile; / global error file name */
31
32	greg	2.1	static char persistfname = NULL; / persist file name */
33			static int persistfd = -1; /* persist file descriptor */
34
35	greg	2.14	static char inpname[TEMPLEN+1], outpname[TEMPLEN+1], errname[TEMPLEN+1];
36	greg	2.1
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	greg	2.14	errname[0] = '\0';
47	greg	2.1	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	greg	2.14	if (errname[0])
62			unlink(errname);
63	greg	2.1	}
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	greg	2.13	persistfd = open(pfn, O_WRONLY\|O_CREAT\|O_EXCL, 0644);
84	greg	2.1	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	greg	2.13	static int got_io;
101	greg	2.1
102	greg	2.13	static int sig_io() { got_io++; }
103	greg	2.1
104	greg	2.13	static int sig_alrm() { quit(0); }
105
106
107	greg	2.1	pfhold() /* holding pattern for idle rendering process */
108			{
109	greg	2.13	int (*oldalrm)();
110	greg	2.12	char buf[512];
111	greg	2.1	register int n;
112			/* close input and output descriptors */
113			close(fileno(stdin));
114			close(fileno(stdout));
115	greg	2.16	if (errfile == NULL)
116			close(fileno(stderr));
117	greg	2.1	/* create named pipes for input and output */
118	greg	2.11	if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO\|0600, 0) < 0)
119	greg	2.1	goto createrr;
120	greg	2.11	if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO\|0600, 0) < 0)
121	greg	2.1	goto createrr;
122	greg	2.14	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	greg	2.1	n = strlen(buf);
128			if (write(persistfd, buf, n) < n)
129	greg	2.10	error(SYSTEM, "error writing persist file");
130	greg	2.18	lseek(persistfd, 0L, 0);
131	greg	2.2	/* wait TIMELIM for someone to signal us */
132	greg	2.13	got_io = 0;
133			signal(SIGIO, sig_io);
134			oldalrm = (int (*)())signal(SIGALRM, sig_alrm);
135	greg	2.2	alarm(TIMELIM);
136	greg	2.15	pflock(0); /* unlock persist file for attach */
137	greg	2.13	while (!got_io)
138	greg	2.15	pause(); /* wait for attach */
139			alarm(0); /* turn off alarm */
140	greg	2.13	signal(SIGALRM, oldalrm);
141	greg	2.2	signal(SIGIO, SIG_DFL);
142	greg	2.17	pflock(1); /* grab persist file back */
143	greg	2.1	/* 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	gregl	2.22	sleep(3); /* give them a chance to open their pipes */
149	greg	2.14	if (errname[0]) {
150			if (freopen(errname, "w", stderr) == NULL)
151			goto openerr;
152			unlink(errname);
153			errname[0] = '\0';
154			}
155	greg	2.1	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	greg	2.16	io_process() /* just act as go-between for actual process */
168	greg	2.1	{
169			register char *cp;
170			register int nr, n;
171	greg	2.16	char buf[BUFSIZ], pfin, pfout, *pferr;
172			int pid, nfds;
173	gregl	2.22	int fdout, fderr = -1;
174	gregl	2.23	int status = 0;
175	gregl	2.22	fd_set readfds, excepfds;
176	greg	2.15	/* load persist file */
177	greg	2.17	n = 40;
178	greg	2.15	while ((nr = read(persistfd, buf, sizeof(buf)-1)) == 0) {
179	greg	2.17	if (!n--)
180			error(USER, "unattended persist file?");
181	greg	2.15	pflock(0);
182	gregl	2.25	sleep(3+(3getpid()+random())%13); / wait until ready */
183	greg	2.15	pflock(1);
184			}
185			if (nr < 0)
186	greg	2.14	error(SYSTEM, "error reading persist file");
187	greg	2.17	ftruncate(persistfd, 0L); /* truncate persist file */
188			pfdetach(); /* close & release persist file */
189			buf[nr] = '\0'; /* parse what we got */
190	greg	2.12	if ((cp = index(buf, ' ')) == NULL)
191	greg	2.1	goto formerr;
192			*cp++ = '\0';
193	greg	2.12	if ((pid = atoi(cp)) <= 0)
194	greg	2.1	goto formerr;
195			if ((cp = index(cp, '\n')) == NULL)
196			goto formerr;
197	greg	2.12	pfin = ++cp;
198			if ((cp = index(cp, '\n')) == NULL)
199			goto formerr;
200	greg	2.1	*cp++ = '\0';
201			pfout = cp;
202			if ((cp = index(cp, '\n')) == NULL)
203			goto formerr;
204			*cp++ = '\0';
205	greg	2.14	pferr = cp;
206			if ((cp = index(cp, '\n')) == NULL)
207			goto formerr;
208			*cp++ = '\0';
209	greg	2.1	if (cp-buf != nr)
210			goto formerr;
211	greg	2.12	if (strcmp(buf, progname)) {
212			sprintf(errmsg, "persist file for %s, not %s", buf, progname);
213			error(USER, errmsg);
214			}
215	greg	2.16	/* wake up rendering process */
216	greg	2.2	if (kill(pid, SIGIO) < 0)
217	greg	2.1	error(SYSTEM, "cannot signal rendering process in io_process");
218	gregl	2.22	/* 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	greg	2.16	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	gregl	2.22	for ( ; ; ) { /* eater loop */
246	greg	2.16	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	greg	2.14	}
254	greg	2.16	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	gregl	2.22	if (select(nfds, &readfds, NULL, &excepfds, NULL) < 0)
262	greg	2.16	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	greg	2.18	/* close(2); don't close stderr! */
272	greg	2.16	fderr = -1;
273	gregl	2.24	} else {
274	gregl	2.23	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	greg	2.16	if ((n = write(2, cp, nr)) <= 0)
291			goto writerr;
292			cp += n;
293			} while ((nr -= n) > 0);
294	gregl	2.24	}
295	greg	2.16	}
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	greg	2.1	}
314	gregl	2.23	wait(0); /* wait for feeder process */
315			_exit(status);
316	greg	2.1	formerr:
317			error(USER, "format error in persist file");
318	greg	2.16	readerr:
319			error(SYSTEM, "read error in io_process");
320			writerr:
321			error(SYSTEM, "write error in io_process");
322	greg	2.1	}
323	greg	2.6
324	greg	2.8	#else
325
326			pfclean() {}
327
328	greg	2.6	#endif