src/rt/persist.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 * Routines for persistent rtrace and rpict processes.
 *
 *  External symbols declared in ray.h
 */

/* ====================================================================
 * The Radiance Software License, Version 1.0
 *
 * Copyright (c) 1990 - 2002 The Regents of the University of California,
 * through Lawrence Berkeley National Laboratory.   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *           if any, must include the following acknowledgment:
 *             "This product includes Radiance software
 *                 (http://radsite.lbl.gov/)
 *                 developed by the Lawrence Berkeley National Laboratory
 *               (http://www.lbl.gov/)."
 *       Alternately, this acknowledgment may appear in the software itself,
 *       if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
 *       and "The Regents of the University of California" must
 *       not be used to endorse or promote products derived from this
 *       software without prior written permission. For written
 *       permission, please contact [email protected].
 *
 * 5. Products derived from this software may not be called "Radiance",
 *       nor may "Radiance" appear in their name, without prior written
 *       permission of Lawrence Berkeley National Laboratory.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Lawrence Berkeley National Laboratory.   For more
 * information on Lawrence Berkeley National Laboratory, please see
 * <http://www.lbl.gov/>.
 */

#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

#ifndef freebsd
#define mkfifo(fn,md)   mknod(fn, S_IFIFO|(md), 0)
#endif

extern void     io_process();

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];


void
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;
}


void
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);
}


void
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 void sig_io() { got_io++; }

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


void
pfhold()                /* holding pattern for idle rendering process */
{
        void    (*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 (mkfifo(mktemp(strcpy(inpname,TEMPLATE)), 0600) < 0)
                goto createrr;
        if (mkfifo(mktemp(strcpy(outpname,TEMPLATE)), 0600) < 0)
                goto createrr;
        if (errfile == NULL &&
                mkfifo(mktemp(strcpy(errname,TEMPLATE)), 0600) < 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, (off_t)0L, 0);
                                /* wait TIMELIM for someone to signal us */
        got_io = 0;
        signal(SIGIO, sig_io);
        oldalrm = (void (*)())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;
        */
        close(0);
        if (open(inpname, O_RDONLY) != 0)
                error(INTERNAL, "unexpected stdin file number");
        clearerr(stdin);
        close(1);
        if (open(outpname, O_WRONLY) != 1)
                error(INTERNAL, "unexpected stdout file number");
        sleep(3);               /* give them a chance to open their pipes */
        if (errname[0]) {
                close(2);
                if (open(errname, O_WRONLY) != 2)
                        error(INTERNAL, "unexpected stderr file number");
                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");
}


void
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, (off_t)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

void pfclean() {}

#endif
Revision:	2.26
Committed:	Sat Feb 22 02:07:29 2003 UTC (21 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.25:	+92 -17 lines
Log Message:	Changes and check-in for 3.5 release Includes new source files and modifications not recorded for many years See ray/doc/notes/ReleaseNotes for notes between 3.1 and 3.5 release
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.26	static const char RCSid[] = "$Id$";
3	greg	2.1	#endif
4			/*
5			* Routines for persistent rtrace and rpict processes.
6	greg	2.26	*
7			* External symbols declared in ray.h
8			*/
9
10			/* ====================================================================
11			* The Radiance Software License, Version 1.0
12			*
13			* Copyright (c) 1990 - 2002 The Regents of the University of California,
14			* through Lawrence Berkeley National Laboratory. All rights reserved.
15			*
16			* Redistribution and use in source and binary forms, with or without
17			* modification, are permitted provided that the following conditions
18			* are met:
19			*
20			* 1. Redistributions of source code must retain the above copyright
21			* notice, this list of conditions and the following disclaimer.
22			*
23			* 2. Redistributions in binary form must reproduce the above copyright
24			* notice, this list of conditions and the following disclaimer in
25			* the documentation and/or other materials provided with the
26			* distribution.
27			*
28			* 3. The end-user documentation included with the redistribution,
29			* if any, must include the following acknowledgment:
30			* "This product includes Radiance software
31			* (http://radsite.lbl.gov/)
32			* developed by the Lawrence Berkeley National Laboratory
33			* (http://www.lbl.gov/)."
34			* Alternately, this acknowledgment may appear in the software itself,
35			* if and wherever such third-party acknowledgments normally appear.
36			*
37			* 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
38			* and "The Regents of the University of California" must
39			* not be used to endorse or promote products derived from this
40			* software without prior written permission. For written
41			* permission, please contact [email protected].
42			*
43			* 5. Products derived from this software may not be called "Radiance",
44			* nor may "Radiance" appear in their name, without prior written
45			* permission of Lawrence Berkeley National Laboratory.
46			*
47			* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
48			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
49			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
50			* DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
51			* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
52			* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
53			* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
54			* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
55			* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
56			* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
57			* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58			* SUCH DAMAGE.
59			* ====================================================================
60			*
61			* This software consists of voluntary contributions made by many
62			* individuals on behalf of Lawrence Berkeley National Laboratory. For more
63			* information on Lawrence Berkeley National Laboratory, please see
64			* <http://www.lbl.gov/>.
65	greg	2.1	*/
66
67			#include "standard.h"
68	gregl	2.25	#include "random.h"
69	greg	2.6
70			#ifdef F_SETLKW
71	greg	2.1	#include "paths.h"
72	gregl	2.21	#include "selcall.h"
73	greg	2.1	#include <signal.h>
74			#include <sys/stat.h>
75
76	greg	2.2	#ifndef TIMELIM
77			#define TIMELIM (83600) / time limit for holding pattern */
78			#endif
79
80	greg	2.26	#ifndef freebsd
81			#define mkfifo(fn,md) mknod(fn, S_IFIFO\|(md), 0)
82			#endif
83
84			extern void io_process();
85	greg	2.1
86			extern int headismine; /* boolean true if header belongs to me */
87
88	greg	2.12	extern char progname; / global program name */
89
90	greg	2.14	extern char errfile; / global error file name */
91
92	greg	2.1	static char persistfname = NULL; / persist file name */
93			static int persistfd = -1; /* persist file descriptor */
94
95	greg	2.14	static char inpname[TEMPLEN+1], outpname[TEMPLEN+1], errname[TEMPLEN+1];
96	greg	2.1
97
98	greg	2.26	void
99	greg	2.1	pfdetach() /* release persist (and header) resources */
100			{
101			if (persistfd >= 0)
102			close(persistfd);
103			persistfd = -1;
104			persistfname = NULL;
105			inpname[0] = '\0';
106			outpname[0] = '\0';
107	greg	2.14	errname[0] = '\0';
108	greg	2.1	headismine = 0;
109			}
110
111
112	greg	2.26	void
113	greg	2.1	pfclean() /* clean up persist files */
114			{
115			if (persistfd >= 0)
116			close(persistfd);
117			if (persistfname != NULL)
118			unlink(persistfname);
119			if (inpname[0])
120			unlink(inpname);
121			if (outpname[0])
122			unlink(outpname);
123	greg	2.14	if (errname[0])
124			unlink(errname);
125	greg	2.1	}
126
127
128	greg	2.26	void
129	greg	2.1	pflock(lf) /* place or release exclusive lock on file */
130			int lf;
131			{
132			struct flock fls;
133
134			fls.l_type = lf ? F_WRLCK : F_UNLCK;
135			fls.l_whence = 0;
136			fls.l_start = 0L;
137			fls.l_len = 0L;
138			if (fcntl(persistfd, F_SETLKW, &fls) < 0)
139			error(SYSTEM, "cannot (un)lock persist file");
140			}
141
142
143			persistfile(pfn) /* open persist file and lock it */
144			char *pfn;
145			{
146	greg	2.13	persistfd = open(pfn, O_WRONLY\|O_CREAT\|O_EXCL, 0644);
147	greg	2.1	if (persistfd >= 0) {
148			persistfname = pfn;
149			pflock(1);
150			return;
151			}
152			/* file exists -- switch to i/o process */
153			persistfd = open(pfn, O_RDWR);
154			if (persistfd < 0) {
155			sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
156			error(SYSTEM, errmsg);
157			}
158			pflock(1);
159			io_process(); /* never returns */
160			}
161
162
163	greg	2.13	static int got_io;
164	greg	2.1
165	greg	2.26	static void sig_io() { got_io++; }
166	greg	2.1
167	greg	2.26	static void sig_alrm() { quit(0); }
168	greg	2.13
169
170	greg	2.26	void
171	greg	2.1	pfhold() /* holding pattern for idle rendering process */
172			{
173	greg	2.26	void (*oldalrm)();
174	greg	2.12	char buf[512];
175	greg	2.1	register int n;
176			/* close input and output descriptors */
177			close(fileno(stdin));
178			close(fileno(stdout));
179	greg	2.16	if (errfile == NULL)
180			close(fileno(stderr));
181	greg	2.1	/* create named pipes for input and output */
182	greg	2.26	if (mkfifo(mktemp(strcpy(inpname,TEMPLATE)), 0600) < 0)
183	greg	2.1	goto createrr;
184	greg	2.26	if (mkfifo(mktemp(strcpy(outpname,TEMPLATE)), 0600) < 0)
185	greg	2.1	goto createrr;
186	greg	2.14	if (errfile == NULL &&
187	greg	2.26	mkfifo(mktemp(strcpy(errname,TEMPLATE)), 0600) < 0)
188	greg	2.14	goto createrr;
189			sprintf(buf, "%s %d\n%s\n%s\n%s\n", progname, getpid(),
190			inpname, outpname, errname);
191	greg	2.1	n = strlen(buf);
192			if (write(persistfd, buf, n) < n)
193	greg	2.10	error(SYSTEM, "error writing persist file");
194	greg	2.26	lseek(persistfd, (off_t)0L, 0);
195	greg	2.2	/* wait TIMELIM for someone to signal us */
196	greg	2.13	got_io = 0;
197			signal(SIGIO, sig_io);
198	greg	2.26	oldalrm = (void (*)())signal(SIGALRM, sig_alrm);
199	greg	2.2	alarm(TIMELIM);
200	greg	2.15	pflock(0); /* unlock persist file for attach */
201	greg	2.13	while (!got_io)
202	greg	2.15	pause(); /* wait for attach */
203			alarm(0); /* turn off alarm */
204	greg	2.13	signal(SIGALRM, oldalrm);
205	greg	2.2	signal(SIGIO, SIG_DFL);
206	greg	2.17	pflock(1); /* grab persist file back */
207	greg	2.1	/* someone wants us; reopen stdin and stdout */
208	greg	2.26	/*
209	greg	2.1	if (freopen(inpname, "r", stdin) == NULL)
210			goto openerr;
211			if (freopen(outpname, "w", stdout) == NULL)
212			goto openerr;
213	greg	2.26	*/
214			close(0);
215			if (open(inpname, O_RDONLY) != 0)
216			error(INTERNAL, "unexpected stdin file number");
217			clearerr(stdin);
218			close(1);
219			if (open(outpname, O_WRONLY) != 1)
220			error(INTERNAL, "unexpected stdout file number");
221	gregl	2.22	sleep(3); /* give them a chance to open their pipes */
222	greg	2.14	if (errname[0]) {
223	greg	2.26	close(2);
224			if (open(errname, O_WRONLY) != 2)
225			error(INTERNAL, "unexpected stderr file number");
226	greg	2.14	unlink(errname);
227			errname[0] = '\0';
228			}
229	greg	2.1	unlink(inpname);
230			inpname[0] = '\0';
231			unlink(outpname);
232			outpname[0] = '\0';
233			return;
234			createrr:
235			error(SYSTEM, "cannot create named pipes in pfhold");
236			openerr:
237			error(SYSTEM, "cannot open named pipes in pfhold");
238			}
239
240
241	greg	2.26	void
242	greg	2.16	io_process() /* just act as go-between for actual process */
243	greg	2.1	{
244			register char *cp;
245			register int nr, n;
246	greg	2.16	char buf[BUFSIZ], pfin, pfout, *pferr;
247			int pid, nfds;
248	gregl	2.22	int fdout, fderr = -1;
249	gregl	2.23	int status = 0;
250	gregl	2.22	fd_set readfds, excepfds;
251	greg	2.15	/* load persist file */
252	greg	2.17	n = 40;
253	greg	2.15	while ((nr = read(persistfd, buf, sizeof(buf)-1)) == 0) {
254	greg	2.17	if (!n--)
255			error(USER, "unattended persist file?");
256	greg	2.15	pflock(0);
257	gregl	2.25	sleep(3+(3getpid()+random())%13); / wait until ready */
258	greg	2.15	pflock(1);
259			}
260			if (nr < 0)
261	greg	2.14	error(SYSTEM, "error reading persist file");
262	greg	2.26	ftruncate(persistfd, (off_t)0L); /* truncate persist file */
263	greg	2.17	pfdetach(); /* close & release persist file */
264			buf[nr] = '\0'; /* parse what we got */
265	greg	2.12	if ((cp = index(buf, ' ')) == NULL)
266	greg	2.1	goto formerr;
267			*cp++ = '\0';
268	greg	2.12	if ((pid = atoi(cp)) <= 0)
269	greg	2.1	goto formerr;
270			if ((cp = index(cp, '\n')) == NULL)
271			goto formerr;
272	greg	2.12	pfin = ++cp;
273			if ((cp = index(cp, '\n')) == NULL)
274			goto formerr;
275	greg	2.1	*cp++ = '\0';
276			pfout = cp;
277			if ((cp = index(cp, '\n')) == NULL)
278			goto formerr;
279			*cp++ = '\0';
280	greg	2.14	pferr = cp;
281			if ((cp = index(cp, '\n')) == NULL)
282			goto formerr;
283			*cp++ = '\0';
284	greg	2.1	if (cp-buf != nr)
285			goto formerr;
286	greg	2.12	if (strcmp(buf, progname)) {
287			sprintf(errmsg, "persist file for %s, not %s", buf, progname);
288			error(USER, errmsg);
289			}
290	greg	2.16	/* wake up rendering process */
291	greg	2.2	if (kill(pid, SIGIO) < 0)
292	greg	2.1	error(SYSTEM, "cannot signal rendering process in io_process");
293	gregl	2.22	/* fork child feeder process */
294			pid = fork();
295			if (pid < 0)
296			error(SYSTEM, "fork failed in io_process");
297			if (pid == 0) { /* feeder loop */
298			int fdin;
299			close(1); /* open input pipe */
300			if ((fdin = open(pfin, O_WRONLY)) < 0)
301			error(SYSTEM, "cannot open feed pipe in io_process");
302			/* renderer stdin */
303			while ((nr = read(0, cp=buf, sizeof(buf))) > 0) {
304			do {
305			if ((n = write(fdin, cp, nr)) <= 0)
306			goto writerr;
307			cp += n;
308			} while ((nr -= n) > 0);
309			}
310			if (nr < 0)
311			goto readerr;
312			_exit(0);
313			}
314			close(0);
315			/* open output pipes, in order */
316	greg	2.16	if ((fdout = open(pfout, O_RDONLY)) < 0)
317			error(SYSTEM, "cannot open output pipe in io_process");
318			if (pferr[0] && (fderr = open(pferr, O_RDONLY)) < 0)
319			error(SYSTEM, "cannot open error pipe in io_process");
320	gregl	2.22	for ( ; ; ) { /* eater loop */
321	greg	2.16	FD_ZERO(&readfds);
322			FD_ZERO(&excepfds);
323			nfds = 0;
324			if (fdout >= 0) {
325			FD_SET(fdout, &readfds);
326			FD_SET(fdout, &excepfds);
327			nfds = fdout+1;
328	greg	2.14	}
329	greg	2.16	if (fderr >= 0) {
330			FD_SET(fderr, &readfds);
331			FD_SET(fderr, &excepfds);
332			nfds = fderr+1;
333			}
334			if (nfds == 0)
335			break; /* all done, exit */
336	gregl	2.22	if (select(nfds, &readfds, NULL, &excepfds, NULL) < 0)
337	greg	2.16	error(SYSTEM, "error in select call in io_process");
338			/* renderer stderr */
339			if (fderr >= 0 && (FD_ISSET(fderr, &readfds) \|\|
340			FD_ISSET(fderr, &excepfds))) {
341			nr = read(fderr, cp=buf, sizeof(buf));
342			if (nr < 0)
343			goto readerr;
344			if (nr == 0) {
345			close(fderr);
346	greg	2.18	/* close(2); don't close stderr! */
347	greg	2.16	fderr = -1;
348	gregl	2.24	} else {
349	gregl	2.23	cp[nr] = '\0'; /* deduce status if we can */
350			n = strlen(progname);
351			if (!strncmp(cp, progname, n) &&
352			cp[n++] == ':' &&
353			cp[n++] == ' ') {
354			register struct erract *ep;
355			for (ep = erract; ep < erract+NERRS;
356			ep++)
357			if (ep->pre[0] &&
358			!strncmp(cp+n, ep->pre,
359			strlen(ep->pre))) {
360			status = ep->ec;
361			break;
362			}
363			}
364			do { /* write message */
365	greg	2.16	if ((n = write(2, cp, nr)) <= 0)
366			goto writerr;
367			cp += n;
368			} while ((nr -= n) > 0);
369	gregl	2.24	}
370	greg	2.16	}
371			/* renderer stdout */
372			if (fdout >= 0 && (FD_ISSET(fdout, &readfds) \|\|
373			FD_ISSET(fdout, &excepfds))) {
374			nr = read(fdout, cp=buf, sizeof(buf));
375			if (nr < 0)
376			goto readerr;
377			if (nr == 0) { /* EOF */
378			close(fdout);
379			close(1);
380			fdout = -1;
381			} else
382			do { /* write it all */
383			if ((n = write(1, cp, nr)) <= 0)
384			goto writerr;
385			cp += n;
386			} while ((nr -= n) > 0);
387			}
388	greg	2.1	}
389	gregl	2.23	wait(0); /* wait for feeder process */
390			_exit(status);
391	greg	2.1	formerr:
392			error(USER, "format error in persist file");
393	greg	2.16	readerr:
394			error(SYSTEM, "read error in io_process");
395			writerr:
396			error(SYSTEM, "write error in io_process");
397	greg	2.1	}
398	greg	2.6
399	greg	2.8	#else
400
401	greg	2.26	void pfclean() {}
402	greg	2.8
403	greg	2.6	#endif