src/rt/persist.c

#ifndef lint
static const char       RCSid[] = "$Id: persist.c,v 2.29 2003/06/30 14:59:12 schorsch Exp $";
#endif
/*
 * Routines for persistent rtrace and rpict processes.
 *
 *  External symbols declared in ray.h
 */

#include "copyright.h"

#include <string.h>
#include <signal.h>
#include <sys/stat.h>

#include "rtprocess.h" /* getpid() */
#include "standard.h"
#include "random.h"

#ifdef F_SETLKW
#include "paths.h"
#include "selcall.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");
}


void
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");
#ifndef _WIN32 /* XXX we need a replacement for that one */
        ftruncate(persistfd, (off_t)0L);        /* truncate persist file */
#endif
        pfdetach();                     /* close & release persist file */
        buf[nr] = '\0';                 /* parse what we got */
        if ((cp = strchr(buf, ' ')) == NULL)
                goto formerr;
        *cp++ = '\0';
        if ((pid = atoi(cp)) <= 0)
                goto formerr;
        if ((cp = strchr(cp, '\n')) == NULL)
                goto formerr;
        pfin = ++cp;
        if ((cp = strchr(cp, '\n')) == NULL)
                goto formerr;
        *cp++ = '\0';
        pfout = cp;
        if ((cp = strchr(cp, '\n')) == NULL)
                goto formerr;
        *cp++ = '\0';
        pferr = cp;
        if ((cp = strchr(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:	2.30
Committed:	Mon Jul 14 20:02:30 2003 UTC (20 years, 9 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.29:	+3 -4 lines
Log Message:	Moved some more platform dependencies to common header files. Included a few necessary system headers.
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	schorsch	2.30	static const char RCSid[] = "$Id: persist.c,v 2.29 2003/06/30 14:59:12 schorsch Exp $";
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	greg	2.27	#include "copyright.h"
11	greg	2.1
12	schorsch	2.29	#include <string.h>
13			#include <signal.h>
14			#include <sys/stat.h>
15
16	schorsch	2.30	#include "rtprocess.h" /* getpid() */
17	greg	2.1	#include "standard.h"
18	gregl	2.25	#include "random.h"
19	greg	2.6
20			#ifdef F_SETLKW
21	greg	2.1	#include "paths.h"
22	gregl	2.21	#include "selcall.h"
23	greg	2.1
24	greg	2.2	#ifndef TIMELIM
25			#define TIMELIM (83600) / time limit for holding pattern */
26			#endif
27
28	greg	2.26	#ifndef freebsd
29			#define mkfifo(fn,md) mknod(fn, S_IFIFO\|(md), 0)
30			#endif
31
32			extern void io_process();
33	greg	2.1
34			extern int headismine; /* boolean true if header belongs to me */
35
36	greg	2.12	extern char progname; / global program name */
37
38	greg	2.14	extern char errfile; / global error file name */
39
40	greg	2.1	static char persistfname = NULL; / persist file name */
41			static int persistfd = -1; /* persist file descriptor */
42
43	greg	2.14	static char inpname[TEMPLEN+1], outpname[TEMPLEN+1], errname[TEMPLEN+1];
44	greg	2.1
45
46	greg	2.26	void
47	greg	2.1	pfdetach() /* release persist (and header) resources */
48			{
49			if (persistfd >= 0)
50			close(persistfd);
51			persistfd = -1;
52			persistfname = NULL;
53			inpname[0] = '\0';
54			outpname[0] = '\0';
55	greg	2.14	errname[0] = '\0';
56	greg	2.1	headismine = 0;
57			}
58
59
60	greg	2.26	void
61	greg	2.1	pfclean() /* clean up persist files */
62			{
63			if (persistfd >= 0)
64			close(persistfd);
65			if (persistfname != NULL)
66			unlink(persistfname);
67			if (inpname[0])
68			unlink(inpname);
69			if (outpname[0])
70			unlink(outpname);
71	greg	2.14	if (errname[0])
72			unlink(errname);
73	greg	2.1	}
74
75
76	greg	2.26	void
77	greg	2.1	pflock(lf) /* place or release exclusive lock on file */
78			int lf;
79			{
80			struct flock fls;
81
82			fls.l_type = lf ? F_WRLCK : F_UNLCK;
83			fls.l_whence = 0;
84			fls.l_start = 0L;
85			fls.l_len = 0L;
86			if (fcntl(persistfd, F_SETLKW, &fls) < 0)
87			error(SYSTEM, "cannot (un)lock persist file");
88			}
89
90
91	schorsch	2.30	void
92	greg	2.1	persistfile(pfn) /* open persist file and lock it */
93			char *pfn;
94			{
95	greg	2.13	persistfd = open(pfn, O_WRONLY\|O_CREAT\|O_EXCL, 0644);
96	greg	2.1	if (persistfd >= 0) {
97			persistfname = pfn;
98			pflock(1);
99			return;
100			}
101			/* file exists -- switch to i/o process */
102			persistfd = open(pfn, O_RDWR);
103			if (persistfd < 0) {
104			sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
105			error(SYSTEM, errmsg);
106			}
107			pflock(1);
108			io_process(); /* never returns */
109			}
110
111
112	greg	2.13	static int got_io;
113	greg	2.1
114	greg	2.26	static void sig_io() { got_io++; }
115	greg	2.1
116	greg	2.26	static void sig_alrm() { quit(0); }
117	greg	2.13
118
119	greg	2.26	void
120	greg	2.1	pfhold() /* holding pattern for idle rendering process */
121			{
122	greg	2.26	void (*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	2.26	if (mkfifo(mktemp(strcpy(inpname,TEMPLATE)), 0600) < 0)
132	greg	2.1	goto createrr;
133	greg	2.26	if (mkfifo(mktemp(strcpy(outpname,TEMPLATE)), 0600) < 0)
134	greg	2.1	goto createrr;
135	greg	2.14	if (errfile == NULL &&
136	greg	2.26	mkfifo(mktemp(strcpy(errname,TEMPLATE)), 0600) < 0)
137	greg	2.14	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			if (write(persistfd, buf, n) < n)
142	greg	2.10	error(SYSTEM, "error writing persist file");
143	greg	2.26	lseek(persistfd, (off_t)0L, 0);
144	greg	2.2	/* wait TIMELIM for someone to signal us */
145	greg	2.13	got_io = 0;
146			signal(SIGIO, sig_io);
147	greg	2.26	oldalrm = (void (*)())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	greg	2.26	/*
158	greg	2.1	if (freopen(inpname, "r", stdin) == NULL)
159			goto openerr;
160			if (freopen(outpname, "w", stdout) == NULL)
161			goto openerr;
162	greg	2.26	*/
163			close(0);
164			if (open(inpname, O_RDONLY) != 0)
165			error(INTERNAL, "unexpected stdin file number");
166			clearerr(stdin);
167			close(1);
168			if (open(outpname, O_WRONLY) != 1)
169			error(INTERNAL, "unexpected stdout file number");
170	gregl	2.22	sleep(3); /* give them a chance to open their pipes */
171	greg	2.14	if (errname[0]) {
172	greg	2.26	close(2);
173			if (open(errname, O_WRONLY) != 2)
174			error(INTERNAL, "unexpected stderr file number");
175	greg	2.14	unlink(errname);
176			errname[0] = '\0';
177			}
178	greg	2.1	unlink(inpname);
179			inpname[0] = '\0';
180			unlink(outpname);
181			outpname[0] = '\0';
182			return;
183			createrr:
184			error(SYSTEM, "cannot create named pipes in pfhold");
185			openerr:
186			error(SYSTEM, "cannot open named pipes in pfhold");
187			}
188
189
190	greg	2.26	void
191	greg	2.16	io_process() /* just act as go-between for actual process */
192	greg	2.1	{
193			register char *cp;
194			register int nr, n;
195	greg	2.16	char buf[BUFSIZ], pfin, pfout, *pferr;
196			int pid, nfds;
197	gregl	2.22	int fdout, fderr = -1;
198	gregl	2.23	int status = 0;
199	gregl	2.22	fd_set readfds, excepfds;
200	greg	2.15	/* load persist file */
201	greg	2.17	n = 40;
202	greg	2.15	while ((nr = read(persistfd, buf, sizeof(buf)-1)) == 0) {
203	greg	2.17	if (!n--)
204			error(USER, "unattended persist file?");
205	greg	2.15	pflock(0);
206	gregl	2.25	sleep(3+(3getpid()+random())%13); / wait until ready */
207	greg	2.15	pflock(1);
208			}
209			if (nr < 0)
210	greg	2.14	error(SYSTEM, "error reading persist file");
211	schorsch	2.28	#ifndef _WIN32 /* XXX we need a replacement for that one */
212	greg	2.26	ftruncate(persistfd, (off_t)0L); /* truncate persist file */
213	schorsch	2.28	#endif
214	greg	2.17	pfdetach(); /* close & release persist file */
215			buf[nr] = '\0'; /* parse what we got */
216	schorsch	2.29	if ((cp = strchr(buf, ' ')) == NULL)
217	greg	2.1	goto formerr;
218			*cp++ = '\0';
219	greg	2.12	if ((pid = atoi(cp)) <= 0)
220	greg	2.1	goto formerr;
221	schorsch	2.29	if ((cp = strchr(cp, '\n')) == NULL)
222	greg	2.1	goto formerr;
223	greg	2.12	pfin = ++cp;
224	schorsch	2.29	if ((cp = strchr(cp, '\n')) == NULL)
225	greg	2.12	goto formerr;
226	greg	2.1	*cp++ = '\0';
227			pfout = cp;
228	schorsch	2.29	if ((cp = strchr(cp, '\n')) == NULL)
229	greg	2.1	goto formerr;
230			*cp++ = '\0';
231	greg	2.14	pferr = cp;
232	schorsch	2.29	if ((cp = strchr(cp, '\n')) == NULL)
233	greg	2.14	goto formerr;
234			*cp++ = '\0';
235	greg	2.1	if (cp-buf != nr)
236			goto formerr;
237	greg	2.12	if (strcmp(buf, progname)) {
238			sprintf(errmsg, "persist file for %s, not %s", buf, progname);
239			error(USER, errmsg);
240			}
241	greg	2.16	/* wake up rendering process */
242	greg	2.2	if (kill(pid, SIGIO) < 0)
243	greg	2.1	error(SYSTEM, "cannot signal rendering process in io_process");
244	gregl	2.22	/* fork child feeder process */
245			pid = fork();
246			if (pid < 0)
247			error(SYSTEM, "fork failed in io_process");
248			if (pid == 0) { /* feeder loop */
249			int fdin;
250			close(1); /* open input pipe */
251			if ((fdin = open(pfin, O_WRONLY)) < 0)
252			error(SYSTEM, "cannot open feed pipe in io_process");
253			/* renderer stdin */
254			while ((nr = read(0, cp=buf, sizeof(buf))) > 0) {
255			do {
256			if ((n = write(fdin, cp, nr)) <= 0)
257			goto writerr;
258			cp += n;
259			} while ((nr -= n) > 0);
260			}
261			if (nr < 0)
262			goto readerr;
263			_exit(0);
264			}
265			close(0);
266			/* open output pipes, in order */
267	greg	2.16	if ((fdout = open(pfout, O_RDONLY)) < 0)
268			error(SYSTEM, "cannot open output pipe in io_process");
269			if (pferr[0] && (fderr = open(pferr, O_RDONLY)) < 0)
270			error(SYSTEM, "cannot open error pipe in io_process");
271	gregl	2.22	for ( ; ; ) { /* eater loop */
272	greg	2.16	FD_ZERO(&readfds);
273			FD_ZERO(&excepfds);
274			nfds = 0;
275			if (fdout >= 0) {
276			FD_SET(fdout, &readfds);
277			FD_SET(fdout, &excepfds);
278			nfds = fdout+1;
279	greg	2.14	}
280	greg	2.16	if (fderr >= 0) {
281			FD_SET(fderr, &readfds);
282			FD_SET(fderr, &excepfds);
283			nfds = fderr+1;
284			}
285			if (nfds == 0)
286			break; /* all done, exit */
287	gregl	2.22	if (select(nfds, &readfds, NULL, &excepfds, NULL) < 0)
288	greg	2.16	error(SYSTEM, "error in select call in io_process");
289			/* renderer stderr */
290			if (fderr >= 0 && (FD_ISSET(fderr, &readfds) \|\|
291			FD_ISSET(fderr, &excepfds))) {
292			nr = read(fderr, cp=buf, sizeof(buf));
293			if (nr < 0)
294			goto readerr;
295			if (nr == 0) {
296			close(fderr);
297	greg	2.18	/* close(2); don't close stderr! */
298	greg	2.16	fderr = -1;
299	gregl	2.24	} else {
300	gregl	2.23	cp[nr] = '\0'; /* deduce status if we can */
301			n = strlen(progname);
302			if (!strncmp(cp, progname, n) &&
303			cp[n++] == ':' &&
304			cp[n++] == ' ') {
305			register struct erract *ep;
306			for (ep = erract; ep < erract+NERRS;
307			ep++)
308			if (ep->pre[0] &&
309			!strncmp(cp+n, ep->pre,
310			strlen(ep->pre))) {
311			status = ep->ec;
312			break;
313			}
314			}
315			do { /* write message */
316	greg	2.16	if ((n = write(2, cp, nr)) <= 0)
317			goto writerr;
318			cp += n;
319			} while ((nr -= n) > 0);
320	gregl	2.24	}
321	greg	2.16	}
322			/* renderer stdout */
323			if (fdout >= 0 && (FD_ISSET(fdout, &readfds) \|\|
324			FD_ISSET(fdout, &excepfds))) {
325			nr = read(fdout, cp=buf, sizeof(buf));
326			if (nr < 0)
327			goto readerr;
328			if (nr == 0) { /* EOF */
329			close(fdout);
330			close(1);
331			fdout = -1;
332			} else
333			do { /* write it all */
334			if ((n = write(1, cp, nr)) <= 0)
335			goto writerr;
336			cp += n;
337			} while ((nr -= n) > 0);
338			}
339	greg	2.1	}
340	gregl	2.23	wait(0); /* wait for feeder process */
341			_exit(status);
342	greg	2.1	formerr:
343			error(USER, "format error in persist file");
344	greg	2.16	readerr:
345			error(SYSTEM, "read error in io_process");
346			writerr:
347			error(SYSTEM, "write error in io_process");
348	greg	2.1	}
349	greg	2.6
350	greg	2.8	#else
351
352	greg	2.26	void pfclean() {}
353	greg	2.8
354	greg	2.6	#endif