src/rt/persist.c

/* Copyright (c) 1996 Regents of the University of California */

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

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

#include "standard.h"

#ifdef F_SETLKW
#include "paths.h"
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
                                        /* select call compatibility stuff */
#ifndef FD_SETSIZE
#include <sys/param.h>
#define FD_SETSIZE      NOFILE          /* maximum # select file descriptors */
#endif
#ifndef FD_SET
#ifndef NFDBITS
#define NFDBITS         (8*sizeof(int)) /* number of bits per fd_mask */
#endif
#define FD_SET(n, p)    ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
#define FD_CLR(n, p)    ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
#define FD_ISSET(n, p)  ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
#define FD_ZERO(p)      bzero((char *)(p), sizeof(*(p)))
#endif

#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);
        lseek(persistfd, 0L, 0);
        if (write(persistfd, buf, n) < n)
                error(SYSTEM, "error writing persist file");
                                /* 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;
        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     fdin, fdout, fderr = -1;
        fd_set  readfds, writefds, 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(15);              /* 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");
                                        /* open named pipes, in order */
        if ((fdin = open(pfin, O_WRONLY)) < 0)
                error(SYSTEM, "cannot open input pipe in io_process");
        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 ( ; ; ) {                   /* loop on select call */
                FD_ZERO(&readfds);
                FD_ZERO(&writefds);
                FD_ZERO(&excepfds);
                nfds = 0;
                if (fdin >= 0) {
                        FD_SET(fdin, &writefds);
                        FD_SET(fdin, &excepfds);
                        nfds = fdin+1;
                }
                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, &writefds, &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);
                                fderr = -1;
                        } else
                                do {            /* write it all */
                                        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);
                }
                                                /* renderer stdin */
                if (fdin >= 0 && (FD_ISSET(fdin, &writefds) ||
                                FD_ISSET(fdin, &excepfds))) {
                        nr = read(0, buf, 512); /* use minimal buffer */
                        if (nr < 0)
                                goto readerr;
                        if (nr == 0) {
                                close(0);
                                close(fdin);
                                fdin = -1;
                        } else if (write(fdin, buf, nr) < nr)
                                goto writerr;   /* what else to do? */
                }
        }
        _exit(0);               /* we ought to return renderer error 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:	2.17
Committed:	Fri Jul 19 10:16:00 1996 UTC (28 years, 3 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.16:	+8 -5 lines
Log Message:	final(?) fix to process synchronization problems
#	User	Rev	Content
1	greg	2.13	/* Copyright (c) 1996 Regents of the University of California */
2	greg	2.1
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	greg	2.6
13			#ifdef F_SETLKW
14	greg	2.1	#include "paths.h"
15			#include <signal.h>
16			#include <sys/types.h>
17			#include <sys/stat.h>
18	greg	2.16	/* 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 (8sizeof(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	greg	2.1
33	greg	2.2	#ifndef TIMELIM
34			#define TIMELIM (83600) / time limit for holding pattern */
35			#endif
36
37	greg	2.1	extern char strcpy(), index();
38
39			extern int headismine; /* boolean true if header belongs to me */
40
41	greg	2.12	extern char progname; / global program name */
42
43	greg	2.14	extern char errfile; / global error file name */
44
45	greg	2.1	static char persistfname = NULL; / persist file name */
46			static int persistfd = -1; /* persist file descriptor */
47
48	greg	2.14	static char inpname[TEMPLEN+1], outpname[TEMPLEN+1], errname[TEMPLEN+1];
49	greg	2.1
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	greg	2.14	errname[0] = '\0';
60	greg	2.1	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	greg	2.14	if (errname[0])
75			unlink(errname);
76	greg	2.1	}
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	greg	2.13	persistfd = open(pfn, O_WRONLY\|O_CREAT\|O_EXCL, 0644);
97	greg	2.1	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	greg	2.13	static int got_io;
114	greg	2.1
115	greg	2.13	static int sig_io() { got_io++; }
116	greg	2.1
117	greg	2.13	static int sig_alrm() { quit(0); }
118
119
120	greg	2.1	pfhold() /* holding pattern for idle rendering process */
121			{
122	greg	2.13	int (*oldalrm)();
123	greg	2.12	char buf[512];
124	greg	2.1	register int n;
125			/* close input and output descriptors */
126			close(fileno(stdin));
127			close(fileno(stdout));
128	greg	2.16	if (errfile == NULL)
129			close(fileno(stderr));
130	greg	2.1	/* create named pipes for input and output */
131	greg	2.11	if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO\|0600, 0) < 0)
132	greg	2.1	goto createrr;
133	greg	2.11	if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO\|0600, 0) < 0)
134	greg	2.1	goto createrr;
135	greg	2.14	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	greg	2.1	n = strlen(buf);
141	greg	2.17	lseek(persistfd, 0L, 0);
142	greg	2.1	if (write(persistfd, buf, n) < n)
143	greg	2.10	error(SYSTEM, "error writing persist file");
144	greg	2.2	/* wait TIMELIM for someone to signal us */
145	greg	2.13	got_io = 0;
146			signal(SIGIO, sig_io);
147			oldalrm = (int (*)())signal(SIGALRM, sig_alrm);
148	greg	2.2	alarm(TIMELIM);
149	greg	2.15	pflock(0); /* unlock persist file for attach */
150	greg	2.13	while (!got_io)
151	greg	2.15	pause(); /* wait for attach */
152			alarm(0); /* turn off alarm */
153	greg	2.13	signal(SIGALRM, oldalrm);
154	greg	2.2	signal(SIGIO, SIG_DFL);
155	greg	2.17	pflock(1); /* grab persist file back */
156	greg	2.1	/* someone wants us; reopen stdin and stdout */
157			if (freopen(inpname, "r", stdin) == NULL)
158			goto openerr;
159			if (freopen(outpname, "w", stdout) == NULL)
160			goto openerr;
161	greg	2.14	if (errname[0]) {
162			if (freopen(errname, "w", stderr) == NULL)
163			goto openerr;
164			unlink(errname);
165			errname[0] = '\0';
166			}
167	greg	2.1	unlink(inpname);
168			inpname[0] = '\0';
169			unlink(outpname);
170			outpname[0] = '\0';
171			return;
172			createrr:
173			error(SYSTEM, "cannot create named pipes in pfhold");
174			openerr:
175			error(SYSTEM, "cannot open named pipes in pfhold");
176			}
177
178
179	greg	2.16	io_process() /* just act as go-between for actual process */
180	greg	2.1	{
181			register char *cp;
182			register int nr, n;
183	greg	2.16	char buf[BUFSIZ], pfin, pfout, *pferr;
184			int pid, nfds;
185			int fdin, fdout, fderr = -1;
186			fd_set readfds, writefds, excepfds;
187	greg	2.15	/* load persist file */
188	greg	2.17	n = 40;
189	greg	2.15	while ((nr = read(persistfd, buf, sizeof(buf)-1)) == 0) {
190	greg	2.17	if (!n--)
191			error(USER, "unattended persist file?");
192	greg	2.15	pflock(0);
193			sleep(15); /* wait until ready */
194			pflock(1);
195			}
196			if (nr < 0)
197	greg	2.14	error(SYSTEM, "error reading persist file");
198	greg	2.17	ftruncate(persistfd, 0L); /* truncate persist file */
199			pfdetach(); /* close & release persist file */
200			buf[nr] = '\0'; /* parse what we got */
201	greg	2.12	if ((cp = index(buf, ' ')) == NULL)
202	greg	2.1	goto formerr;
203			*cp++ = '\0';
204	greg	2.12	if ((pid = atoi(cp)) <= 0)
205	greg	2.1	goto formerr;
206			if ((cp = index(cp, '\n')) == NULL)
207			goto formerr;
208	greg	2.12	pfin = ++cp;
209			if ((cp = index(cp, '\n')) == NULL)
210			goto formerr;
211	greg	2.1	*cp++ = '\0';
212			pfout = cp;
213			if ((cp = index(cp, '\n')) == NULL)
214			goto formerr;
215			*cp++ = '\0';
216	greg	2.14	pferr = cp;
217			if ((cp = index(cp, '\n')) == NULL)
218			goto formerr;
219			*cp++ = '\0';
220	greg	2.1	if (cp-buf != nr)
221			goto formerr;
222	greg	2.12	if (strcmp(buf, progname)) {
223			sprintf(errmsg, "persist file for %s, not %s", buf, progname);
224			error(USER, errmsg);
225			}
226	greg	2.16	/* wake up rendering process */
227	greg	2.2	if (kill(pid, SIGIO) < 0)
228	greg	2.1	error(SYSTEM, "cannot signal rendering process in io_process");
229	greg	2.16	/* open named pipes, in order */
230			if ((fdin = open(pfin, O_WRONLY)) < 0)
231			error(SYSTEM, "cannot open input pipe in io_process");
232			if ((fdout = open(pfout, O_RDONLY)) < 0)
233			error(SYSTEM, "cannot open output pipe in io_process");
234			if (pferr[0] && (fderr = open(pferr, O_RDONLY)) < 0)
235			error(SYSTEM, "cannot open error pipe in io_process");
236			for ( ; ; ) { /* loop on select call */
237			FD_ZERO(&readfds);
238			FD_ZERO(&writefds);
239			FD_ZERO(&excepfds);
240			nfds = 0;
241			if (fdin >= 0) {
242			FD_SET(fdin, &writefds);
243			FD_SET(fdin, &excepfds);
244			nfds = fdin+1;
245	greg	2.14	}
246	greg	2.16	if (fdout >= 0) {
247			FD_SET(fdout, &readfds);
248			FD_SET(fdout, &excepfds);
249			nfds = fdout+1;
250	greg	2.14	}
251	greg	2.16	if (fderr >= 0) {
252			FD_SET(fderr, &readfds);
253			FD_SET(fderr, &excepfds);
254			nfds = fderr+1;
255			}
256			if (nfds == 0)
257			break; /* all done, exit */
258			if (select(nfds, &readfds, &writefds, &excepfds, NULL) < 0)
259			error(SYSTEM, "error in select call in io_process");
260			/* renderer stderr */
261			if (fderr >= 0 && (FD_ISSET(fderr, &readfds) \|\|
262			FD_ISSET(fderr, &excepfds))) {
263			nr = read(fderr, cp=buf, sizeof(buf));
264			if (nr < 0)
265			goto readerr;
266			if (nr == 0) {
267			close(fderr);
268			close(2);
269			fderr = -1;
270			} else
271			do { /* write it all */
272			if ((n = write(2, cp, nr)) <= 0)
273			goto writerr;
274			cp += n;
275			} while ((nr -= n) > 0);
276			}
277			/* renderer stdout */
278			if (fdout >= 0 && (FD_ISSET(fdout, &readfds) \|\|
279			FD_ISSET(fdout, &excepfds))) {
280			nr = read(fdout, cp=buf, sizeof(buf));
281			if (nr < 0)
282			goto readerr;
283			if (nr == 0) { /* EOF */
284			close(fdout);
285			close(1);
286			fdout = -1;
287			} else
288			do { /* write it all */
289			if ((n = write(1, cp, nr)) <= 0)
290			goto writerr;
291			cp += n;
292			} while ((nr -= n) > 0);
293			}
294			/* renderer stdin */
295			if (fdin >= 0 && (FD_ISSET(fdin, &writefds) \|\|
296			FD_ISSET(fdin, &excepfds))) {
297			nr = read(0, buf, 512); /* use minimal buffer */
298			if (nr < 0)
299			goto readerr;
300			if (nr == 0) {
301			close(0);
302			close(fdin);
303			fdin = -1;
304			} else if (write(fdin, buf, nr) < nr)
305			goto writerr; /* what else to do? */
306			}
307	greg	2.1	}
308	greg	2.16	_exit(0); /* we ought to return renderer error status! */
309	greg	2.1	formerr:
310			error(USER, "format error in persist file");
311	greg	2.16	readerr:
312			error(SYSTEM, "read error in io_process");
313			writerr:
314			error(SYSTEM, "write error in io_process");
315	greg	2.1	}
316	greg	2.6
317	greg	2.8	#else
318
319			pfclean() {}
320
321	greg	2.6	#endif