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 "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;
        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(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");
                                        /* 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
                                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);
                }
        }
        _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:	2.22
Committed:	Fri Nov 7 12:12:53 1997 UTC (26 years, 5 months ago) by gregl
Content type:	text/plain
Branch:	MAIN
Changes since 2.21:	+28 -26 lines
Log Message:	went back to separate feeder process, because select() was hanging us
#	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	gregl	2.21	#include "selcall.h"
16	greg	2.1	#include <signal.h>
17			#include <sys/stat.h>
18
19	greg	2.2	#ifndef TIMELIM
20			#define TIMELIM (83600) / time limit for holding pattern */
21			#endif
22
23	greg	2.1	extern char strcpy(), index();
24
25			extern int headismine; /* boolean true if header belongs to me */
26
27	greg	2.12	extern char progname; / global program name */
28
29	greg	2.14	extern char errfile; / global error file name */
30
31	greg	2.1	static char persistfname = NULL; / persist file name */
32			static int persistfd = -1; /* persist file descriptor */
33
34	greg	2.14	static char inpname[TEMPLEN+1], outpname[TEMPLEN+1], errname[TEMPLEN+1];
35	greg	2.1
36
37			pfdetach() /* release persist (and header) resources */
38			{
39			if (persistfd >= 0)
40			close(persistfd);
41			persistfd = -1;
42			persistfname = NULL;
43			inpname[0] = '\0';
44			outpname[0] = '\0';
45	greg	2.14	errname[0] = '\0';
46	greg	2.1	headismine = 0;
47			}
48
49
50			pfclean() /* clean up persist files */
51			{
52			if (persistfd >= 0)
53			close(persistfd);
54			if (persistfname != NULL)
55			unlink(persistfname);
56			if (inpname[0])
57			unlink(inpname);
58			if (outpname[0])
59			unlink(outpname);
60	greg	2.14	if (errname[0])
61			unlink(errname);
62	greg	2.1	}
63
64
65			pflock(lf) /* place or release exclusive lock on file */
66			int lf;
67			{
68			struct flock fls;
69
70			fls.l_type = lf ? F_WRLCK : F_UNLCK;
71			fls.l_whence = 0;
72			fls.l_start = 0L;
73			fls.l_len = 0L;
74			if (fcntl(persistfd, F_SETLKW, &fls) < 0)
75			error(SYSTEM, "cannot (un)lock persist file");
76			}
77
78
79			persistfile(pfn) /* open persist file and lock it */
80			char *pfn;
81			{
82	greg	2.13	persistfd = open(pfn, O_WRONLY\|O_CREAT\|O_EXCL, 0644);
83	greg	2.1	if (persistfd >= 0) {
84			persistfname = pfn;
85			pflock(1);
86			return;
87			}
88			/* file exists -- switch to i/o process */
89			persistfd = open(pfn, O_RDWR);
90			if (persistfd < 0) {
91			sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
92			error(SYSTEM, errmsg);
93			}
94			pflock(1);
95			io_process(); /* never returns */
96			}
97
98
99	greg	2.13	static int got_io;
100	greg	2.1
101	greg	2.13	static int sig_io() { got_io++; }
102	greg	2.1
103	greg	2.13	static int sig_alrm() { quit(0); }
104
105
106	greg	2.1	pfhold() /* holding pattern for idle rendering process */
107			{
108	greg	2.13	int (*oldalrm)();
109	greg	2.12	char buf[512];
110	greg	2.1	register int n;
111			/* close input and output descriptors */
112			close(fileno(stdin));
113			close(fileno(stdout));
114	greg	2.16	if (errfile == NULL)
115			close(fileno(stderr));
116	greg	2.1	/* create named pipes for input and output */
117	greg	2.11	if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO\|0600, 0) < 0)
118	greg	2.1	goto createrr;
119	greg	2.11	if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO\|0600, 0) < 0)
120	greg	2.1	goto createrr;
121	greg	2.14	if (errfile == NULL &&
122			mknod(mktemp(strcpy(errname,TEMPLATE)), S_IFIFO\|0600, 0) < 0)
123			goto createrr;
124			sprintf(buf, "%s %d\n%s\n%s\n%s\n", progname, getpid(),
125			inpname, outpname, errname);
126	greg	2.1	n = strlen(buf);
127			if (write(persistfd, buf, n) < n)
128	greg	2.10	error(SYSTEM, "error writing persist file");
129	greg	2.18	lseek(persistfd, 0L, 0);
130	greg	2.2	/* wait TIMELIM for someone to signal us */
131	greg	2.13	got_io = 0;
132			signal(SIGIO, sig_io);
133			oldalrm = (int (*)())signal(SIGALRM, sig_alrm);
134	greg	2.2	alarm(TIMELIM);
135	greg	2.15	pflock(0); /* unlock persist file for attach */
136	greg	2.13	while (!got_io)
137	greg	2.15	pause(); /* wait for attach */
138			alarm(0); /* turn off alarm */
139	greg	2.13	signal(SIGALRM, oldalrm);
140	greg	2.2	signal(SIGIO, SIG_DFL);
141	greg	2.17	pflock(1); /* grab persist file back */
142	greg	2.1	/* someone wants us; reopen stdin and stdout */
143			if (freopen(inpname, "r", stdin) == NULL)
144			goto openerr;
145			if (freopen(outpname, "w", stdout) == NULL)
146			goto openerr;
147	gregl	2.22	sleep(3); /* give them a chance to open their pipes */
148	greg	2.14	if (errname[0]) {
149			if (freopen(errname, "w", stderr) == NULL)
150			goto openerr;
151			unlink(errname);
152			errname[0] = '\0';
153			}
154	greg	2.1	unlink(inpname);
155			inpname[0] = '\0';
156			unlink(outpname);
157			outpname[0] = '\0';
158			return;
159			createrr:
160			error(SYSTEM, "cannot create named pipes in pfhold");
161			openerr:
162			error(SYSTEM, "cannot open named pipes in pfhold");
163			}
164
165
166	greg	2.16	io_process() /* just act as go-between for actual process */
167	greg	2.1	{
168			register char *cp;
169			register int nr, n;
170	greg	2.16	char buf[BUFSIZ], pfin, pfout, *pferr;
171			int pid, nfds;
172	gregl	2.22	int fdout, fderr = -1;
173			fd_set readfds, excepfds;
174	greg	2.15	/* load persist file */
175	greg	2.17	n = 40;
176	greg	2.15	while ((nr = read(persistfd, buf, sizeof(buf)-1)) == 0) {
177	greg	2.17	if (!n--)
178			error(USER, "unattended persist file?");
179	greg	2.15	pflock(0);
180			sleep(15); /* wait until ready */
181			pflock(1);
182			}
183			if (nr < 0)
184	greg	2.14	error(SYSTEM, "error reading persist file");
185	greg	2.17	ftruncate(persistfd, 0L); /* truncate persist file */
186			pfdetach(); /* close & release persist file */
187			buf[nr] = '\0'; /* parse what we got */
188	greg	2.12	if ((cp = index(buf, ' ')) == NULL)
189	greg	2.1	goto formerr;
190			*cp++ = '\0';
191	greg	2.12	if ((pid = atoi(cp)) <= 0)
192	greg	2.1	goto formerr;
193			if ((cp = index(cp, '\n')) == NULL)
194			goto formerr;
195	greg	2.12	pfin = ++cp;
196			if ((cp = index(cp, '\n')) == NULL)
197			goto formerr;
198	greg	2.1	*cp++ = '\0';
199			pfout = cp;
200			if ((cp = index(cp, '\n')) == NULL)
201			goto formerr;
202			*cp++ = '\0';
203	greg	2.14	pferr = cp;
204			if ((cp = index(cp, '\n')) == NULL)
205			goto formerr;
206			*cp++ = '\0';
207	greg	2.1	if (cp-buf != nr)
208			goto formerr;
209	greg	2.12	if (strcmp(buf, progname)) {
210			sprintf(errmsg, "persist file for %s, not %s", buf, progname);
211			error(USER, errmsg);
212			}
213	greg	2.16	/* wake up rendering process */
214	greg	2.2	if (kill(pid, SIGIO) < 0)
215	greg	2.1	error(SYSTEM, "cannot signal rendering process in io_process");
216	gregl	2.22	/* fork child feeder process */
217			pid = fork();
218			if (pid < 0)
219			error(SYSTEM, "fork failed in io_process");
220			if (pid == 0) { /* feeder loop */
221			int fdin;
222			close(1); /* open input pipe */
223			if ((fdin = open(pfin, O_WRONLY)) < 0)
224			error(SYSTEM, "cannot open feed pipe in io_process");
225			/* renderer stdin */
226			while ((nr = read(0, cp=buf, sizeof(buf))) > 0) {
227			do {
228			if ((n = write(fdin, cp, nr)) <= 0)
229			goto writerr;
230			cp += n;
231			} while ((nr -= n) > 0);
232			}
233			if (nr < 0)
234			goto readerr;
235			_exit(0);
236			}
237			close(0);
238			/* open output pipes, in order */
239	greg	2.16	if ((fdout = open(pfout, O_RDONLY)) < 0)
240			error(SYSTEM, "cannot open output pipe in io_process");
241			if (pferr[0] && (fderr = open(pferr, O_RDONLY)) < 0)
242			error(SYSTEM, "cannot open error pipe in io_process");
243	gregl	2.22	for ( ; ; ) { /* eater loop */
244	greg	2.16	FD_ZERO(&readfds);
245			FD_ZERO(&excepfds);
246			nfds = 0;
247			if (fdout >= 0) {
248			FD_SET(fdout, &readfds);
249			FD_SET(fdout, &excepfds);
250			nfds = fdout+1;
251	greg	2.14	}
252	greg	2.16	if (fderr >= 0) {
253			FD_SET(fderr, &readfds);
254			FD_SET(fderr, &excepfds);
255			nfds = fderr+1;
256			}
257			if (nfds == 0)
258			break; /* all done, exit */
259	gregl	2.22	if (select(nfds, &readfds, NULL, &excepfds, NULL) < 0)
260	greg	2.16	error(SYSTEM, "error in select call in io_process");
261			/* renderer stderr */
262			if (fderr >= 0 && (FD_ISSET(fderr, &readfds) \|\|
263			FD_ISSET(fderr, &excepfds))) {
264			nr = read(fderr, cp=buf, sizeof(buf));
265			if (nr < 0)
266			goto readerr;
267			if (nr == 0) {
268			close(fderr);
269	greg	2.18	/* close(2); don't close stderr! */
270	greg	2.16	fderr = -1;
271			} else
272			do { /* write it all */
273			if ((n = write(2, cp, nr)) <= 0)
274			goto writerr;
275			cp += n;
276			} while ((nr -= n) > 0);
277			}
278			/* renderer stdout */
279			if (fdout >= 0 && (FD_ISSET(fdout, &readfds) \|\|
280			FD_ISSET(fdout, &excepfds))) {
281			nr = read(fdout, cp=buf, sizeof(buf));
282			if (nr < 0)
283			goto readerr;
284			if (nr == 0) { /* EOF */
285			close(fdout);
286			close(1);
287			fdout = -1;
288			} else
289			do { /* write it all */
290			if ((n = write(1, cp, nr)) <= 0)
291			goto writerr;
292			cp += n;
293			} while ((nr -= n) > 0);
294			}
295	greg	2.1	}
296	greg	2.16	_exit(0); /* we ought to return renderer error status! */
297	greg	2.1	formerr:
298			error(USER, "format error in persist file");
299	greg	2.16	readerr:
300			error(SYSTEM, "read error in io_process");
301			writerr:
302			error(SYSTEM, "write error in io_process");
303	greg	2.1	}
304	greg	2.6
305	greg	2.8	#else
306
307			pfclean() {}
308
309	greg	2.6	#endif