src/rt/persist.c

/* Copyright (c) 1993 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>

#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 */

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

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


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


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, 0666);
        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 */
}


int sig_noop() {}


pfhold()                /* holding pattern for idle rendering process */
{
        char    buf[128];
        register int    n;
                                /* close input and output descriptors */
        close(fileno(stdin));
        close(fileno(stdout));
                                /* create named pipes for input and output */
        if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO|0600) < 0)
                goto createrr;
        if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO|0600) < 0)
                goto createrr;
        sprintf(buf, "%d\n%s\n%s\n", getpid(), inpname, outpname);
        if (lseek(persistfd, 0L, 0) < 0)
                error(SYSTEM, "seek error on persist file in pfhold");
        n = strlen(buf);
        if (write(persistfd, buf, n) < n)
                error(SYSTEM, "error writing persist file in pfhold");
                                /* wait TIMELIM for someone to signal us */
        signal(SIGIO, sig_noop);
        alarm(TIMELIM);
        pflock(0);
        pause();
        alarm(0);
        signal(SIGIO, SIG_DFL);
        pflock(1);
                                /* someone wants us; reopen stdin and stdout */
        if (freopen(inpname, "r", stdin) == NULL)
                goto openerr;
        if (freopen(outpname, "w", stdout) == NULL)
                goto openerr;
        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 conduits to and from actual process */
{
        register char   *cp;
        register int    nr, n;
        char    buf[4096], *pfin, *pfout;
        int     pid;
                                /* load and close persist file */
        nr = read(persistfd, buf, sizeof(buf));
        pfdetach();
        if (nr < 0)
                error(SYSTEM, "cannot read persist file");
        buf[nr] = '\0';
        if ((cp = index(buf, '\n')) == NULL)
                goto formerr;
        *cp++ = '\0';
        if ((pid = atoi(buf)) <= 0)
                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';
        if (cp-buf != nr)
                goto formerr;
                                /* wake up rendering process */
        if (kill(pid, SIGIO) < 0)
                error(SYSTEM, "cannot signal rendering process in io_process");
        pid = fork();           /* fork i/o process */
        if (pid < 0)
                error(SYSTEM, "fork failed in io_process");
                                /* connect to appropriate pipe */
        if (pid) {                      /* parent passes renderer output */
                close(0);
                if (open(pfout, O_RDONLY) != 0)
                        error(SYSTEM, "cannot open input pipe in io_process");
        } else {                        /* child passes renderer input */
                close(1);
                if (open(pfin, O_WRONLY) != 1)
                        error(SYSTEM, "cannot open output pipe in io_process");
        }
                                /* pass input to output */
        cp = buf; n = sizeof(buf);
                                /* do as much as we can each way */
        while ((nr = read(0, cp, n)) > 0) {
                nr += cp-buf;
                if ((n = write(1, buf, nr)) <= 0)
                        goto writerr;
                cp = buf;
                while (n < nr)
                        *cp++ = buf[n++];
                n = sizeof(buf) - (cp-buf);
        }
        if (nr < 0)
                error(SYSTEM, "read error in io_process");
        close(0);               /* close input */
        nr = cp-buf;            /* write remainder */
        cp = buf;
        while (nr > 0) {
                if ((n = write(1, cp, nr)) <= 0)
                        goto writerr;
                cp += n;
                nr -= n;
        }
        close(1);               /* close output */
        if (pid)                /* parent waits for child */
                wait(0);
        exit(0);                /* all done, exit (not quit!) */
formerr:
        error(USER, "format error in persist file");
writerr:
        error(SYSTEM, "write error in io_process");
}

#else

pfclean() {}

#endif
Revision:	2.8
Committed:	Wed Mar 3 09:07:52 1993 UTC (31 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.7:	+4 -0 lines
Log Message:	added ghost call to pfclean()
#	User	Rev	Content
1	greg	2.1	/* Copyright (c) 1993 Regents of the University of California */
2
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
15	greg	2.1	#include "paths.h"
16			#include <signal.h>
17			#include <sys/types.h>
18			#include <sys/stat.h>
19
20	greg	2.2	#ifndef TIMELIM
21			#define TIMELIM (83600) / time limit for holding pattern */
22			#endif
23
24	greg	2.1	extern char strcpy(), index();
25
26			extern int headismine; /* boolean true if header belongs to me */
27
28			static char persistfname = NULL; / persist file name */
29			static int persistfd = -1; /* persist file descriptor */
30
31			static char inpname[TEMPLEN+1], outpname[TEMPLEN+1];
32
33
34			pfdetach() /* release persist (and header) resources */
35			{
36			if (persistfd >= 0)
37			close(persistfd);
38			persistfd = -1;
39			persistfname = NULL;
40			inpname[0] = '\0';
41			outpname[0] = '\0';
42			headismine = 0;
43			}
44
45
46			pfclean() /* clean up persist files */
47			{
48			if (persistfd >= 0)
49			close(persistfd);
50			if (persistfname != NULL)
51			unlink(persistfname);
52			if (inpname[0])
53			unlink(inpname);
54			if (outpname[0])
55			unlink(outpname);
56			}
57
58
59			pflock(lf) /* place or release exclusive lock on file */
60			int lf;
61			{
62			struct flock fls;
63
64			fls.l_type = lf ? F_WRLCK : F_UNLCK;
65			fls.l_whence = 0;
66			fls.l_start = 0L;
67			fls.l_len = 0L;
68			if (fcntl(persistfd, F_SETLKW, &fls) < 0)
69			error(SYSTEM, "cannot (un)lock persist file");
70			}
71
72
73			persistfile(pfn) /* open persist file and lock it */
74			char *pfn;
75			{
76			persistfd = open(pfn, O_WRONLY\|O_CREAT\|O_EXCL, 0666);
77			if (persistfd >= 0) {
78			persistfname = pfn;
79			pflock(1);
80			return;
81			}
82			/* file exists -- switch to i/o process */
83			persistfd = open(pfn, O_RDWR);
84			if (persistfd < 0) {
85			sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
86			error(SYSTEM, errmsg);
87			}
88			pflock(1);
89			io_process(); /* never returns */
90			}
91
92
93	greg	2.2	int sig_noop() {}
94	greg	2.1
95
96			pfhold() /* holding pattern for idle rendering process */
97			{
98			char buf[128];
99			register int n;
100			/* close input and output descriptors */
101			close(fileno(stdin));
102			close(fileno(stdout));
103			/* create named pipes for input and output */
104			if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO\|0600) < 0)
105			goto createrr;
106			if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO\|0600) < 0)
107			goto createrr;
108			sprintf(buf, "%d\n%s\n%s\n", getpid(), inpname, outpname);
109			if (lseek(persistfd, 0L, 0) < 0)
110			error(SYSTEM, "seek error on persist file in pfhold");
111			n = strlen(buf);
112			if (write(persistfd, buf, n) < n)
113			error(SYSTEM, "error writing persist file in pfhold");
114	greg	2.2	/* wait TIMELIM for someone to signal us */
115			signal(SIGIO, sig_noop);
116			alarm(TIMELIM);
117	greg	2.1	pflock(0);
118			pause();
119	greg	2.2	alarm(0);
120			signal(SIGIO, SIG_DFL);
121	greg	2.1	pflock(1);
122			/* someone wants us; reopen stdin and stdout */
123			if (freopen(inpname, "r", stdin) == NULL)
124			goto openerr;
125			if (freopen(outpname, "w", stdout) == NULL)
126			goto openerr;
127			unlink(inpname);
128			inpname[0] = '\0';
129			unlink(outpname);
130			outpname[0] = '\0';
131			return;
132			createrr:
133			error(SYSTEM, "cannot create named pipes in pfhold");
134			openerr:
135			error(SYSTEM, "cannot open named pipes in pfhold");
136			}
137
138
139			io_process() /* just act as conduits to and from actual process */
140			{
141			register char *cp;
142			register int nr, n;
143			char buf[4096], pfin, pfout;
144			int pid;
145			/* load and close persist file */
146			nr = read(persistfd, buf, sizeof(buf));
147			pfdetach();
148			if (nr < 0)
149			error(SYSTEM, "cannot read persist file");
150			buf[nr] = '\0';
151			if ((cp = index(buf, '\n')) == NULL)
152			goto formerr;
153			*cp++ = '\0';
154			if ((pid = atoi(buf)) <= 0)
155			goto formerr;
156			pfin = cp;
157			if ((cp = index(cp, '\n')) == NULL)
158			goto formerr;
159			*cp++ = '\0';
160			pfout = cp;
161			if ((cp = index(cp, '\n')) == NULL)
162			goto formerr;
163			*cp++ = '\0';
164			if (cp-buf != nr)
165			goto formerr;
166			/* wake up rendering process */
167	greg	2.2	if (kill(pid, SIGIO) < 0)
168	greg	2.1	error(SYSTEM, "cannot signal rendering process in io_process");
169			pid = fork(); /* fork i/o process */
170			if (pid < 0)
171			error(SYSTEM, "fork failed in io_process");
172			/* connect to appropriate pipe */
173			if (pid) { /* parent passes renderer output */
174	greg	2.7	close(0);
175			if (open(pfout, O_RDONLY) != 0)
176	greg	2.1	error(SYSTEM, "cannot open input pipe in io_process");
177			} else { /* child passes renderer input */
178	greg	2.7	close(1);
179			if (open(pfin, O_WRONLY) != 1)
180			error(SYSTEM, "cannot open output pipe in io_process");
181	greg	2.1	}
182			/* pass input to output */
183			cp = buf; n = sizeof(buf);
184	greg	2.7	/* do as much as we can each way */
185			while ((nr = read(0, cp, n)) > 0) {
186	greg	2.1	nr += cp-buf;
187	greg	2.7	if ((n = write(1, buf, nr)) <= 0)
188			goto writerr;
189	greg	2.1	cp = buf;
190			while (n < nr)
191			*cp++ = buf[n++];
192			n = sizeof(buf) - (cp-buf);
193			}
194	greg	2.7	if (nr < 0)
195			error(SYSTEM, "read error in io_process");
196			close(0); /* close input */
197			nr = cp-buf; /* write remainder */
198			cp = buf;
199			while (nr > 0) {
200			if ((n = write(1, cp, nr)) <= 0)
201			goto writerr;
202			cp += n;
203			nr -= n;
204			}
205			close(1); /* close output */
206	greg	2.1	if (pid) /* parent waits for child */
207			wait(0);
208			exit(0); /* all done, exit (not quit!) */
209			formerr:
210			error(USER, "format error in persist file");
211	greg	2.7	writerr:
212			error(SYSTEM, "write error in io_process");
213	greg	2.1	}
214	greg	2.6
215	greg	2.8	#else
216
217			pfclean() {}
218
219	greg	2.6	#endif