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"
#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';
        clean_slate();          /* reset time and ray counters */
        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 */
                if (freopen(pfout, "r", stdin) == NULL)
                        error(SYSTEM, "cannot open input pipe in io_process");
        } else {                        /* child passes renderer input */
                if (freopen(pfin, "w", stdout) == NULL)
                        error(SYSTEM, "cannot open input pipe in io_process");
        }
                                /* pass input to output */
        cp = buf; n = sizeof(buf);
        while ((nr = read(fileno(stdin), cp, n)) > 0) {
                nr += cp-buf;
                if ((n = write(fileno(stdout), buf, nr)) <= 0)
                        error(SYSTEM, "write error in io_process");
                cp = buf;
                while (n < nr)
                        *cp++ = buf[n++];
                n = sizeof(buf) - (cp-buf);
        }
        fclose(stdin);
        fclose(stdout);
        if (pid)                /* parent waits for child */
                wait(0);
        exit(0);                /* all done, exit (not quit!) */
formerr:
        error(USER, "format error in persist file");
}
Revision:	2.4
Committed:	Fri Jan 22 09:51:23 1993 UTC (32 years, 9 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.3:	+0 -1 lines
Log Message:	bug fixes and improvements on stdio flushing
#	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			#include "paths.h"
13			#include <signal.h>
14			#include <sys/types.h>
15			#include <sys/stat.h>
16
17	greg	2.2	#ifndef TIMELIM
18			#define TIMELIM (83600) / time limit for holding pattern */
19			#endif
20
21	greg	2.1	extern char strcpy(), index();
22
23			extern int headismine; /* boolean true if header belongs to me */
24
25			static char persistfname = NULL; / persist file name */
26			static int persistfd = -1; /* persist file descriptor */
27
28			static char inpname[TEMPLEN+1], outpname[TEMPLEN+1];
29
30
31			pfdetach() /* release persist (and header) resources */
32			{
33			if (persistfd >= 0)
34			close(persistfd);
35			persistfd = -1;
36			persistfname = NULL;
37			inpname[0] = '\0';
38			outpname[0] = '\0';
39			headismine = 0;
40			}
41
42
43			pfclean() /* clean up persist files */
44			{
45			if (persistfd >= 0)
46			close(persistfd);
47			if (persistfname != NULL)
48			unlink(persistfname);
49			if (inpname[0])
50			unlink(inpname);
51			if (outpname[0])
52			unlink(outpname);
53			}
54
55
56			pflock(lf) /* place or release exclusive lock on file */
57			int lf;
58			{
59			struct flock fls;
60
61			fls.l_type = lf ? F_WRLCK : F_UNLCK;
62			fls.l_whence = 0;
63			fls.l_start = 0L;
64			fls.l_len = 0L;
65			if (fcntl(persistfd, F_SETLKW, &fls) < 0)
66			error(SYSTEM, "cannot (un)lock persist file");
67			}
68
69
70			persistfile(pfn) /* open persist file and lock it */
71			char *pfn;
72			{
73			persistfd = open(pfn, O_WRONLY\|O_CREAT\|O_EXCL, 0666);
74			if (persistfd >= 0) {
75			persistfname = pfn;
76			pflock(1);
77			return;
78			}
79			/* file exists -- switch to i/o process */
80			persistfd = open(pfn, O_RDWR);
81			if (persistfd < 0) {
82			sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
83			error(SYSTEM, errmsg);
84			}
85			pflock(1);
86			io_process(); /* never returns */
87			}
88
89
90	greg	2.2	int sig_noop() {}
91	greg	2.1
92
93			pfhold() /* holding pattern for idle rendering process */
94			{
95			char buf[128];
96			register int n;
97			/* close input and output descriptors */
98			close(fileno(stdin));
99			close(fileno(stdout));
100			/* create named pipes for input and output */
101			if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO\|0600) < 0)
102			goto createrr;
103			if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO\|0600) < 0)
104			goto createrr;
105			sprintf(buf, "%d\n%s\n%s\n", getpid(), inpname, outpname);
106			if (lseek(persistfd, 0L, 0) < 0)
107			error(SYSTEM, "seek error on persist file in pfhold");
108			n = strlen(buf);
109			if (write(persistfd, buf, n) < n)
110			error(SYSTEM, "error writing persist file in pfhold");
111	greg	2.2	/* wait TIMELIM for someone to signal us */
112			signal(SIGIO, sig_noop);
113			alarm(TIMELIM);
114	greg	2.1	pflock(0);
115			pause();
116	greg	2.2	alarm(0);
117			signal(SIGIO, SIG_DFL);
118	greg	2.1	pflock(1);
119			/* someone wants us; reopen stdin and stdout */
120			if (freopen(inpname, "r", stdin) == NULL)
121			goto openerr;
122			if (freopen(outpname, "w", stdout) == NULL)
123			goto openerr;
124			unlink(inpname);
125			inpname[0] = '\0';
126			unlink(outpname);
127			outpname[0] = '\0';
128	greg	2.3	clean_slate(); /* reset time and ray counters */
129	greg	2.1	return;
130			createrr:
131			error(SYSTEM, "cannot create named pipes in pfhold");
132			openerr:
133			error(SYSTEM, "cannot open named pipes in pfhold");
134			}
135
136
137			io_process() /* just act as conduits to and from actual process */
138			{
139			register char *cp;
140			register int nr, n;
141			char buf[4096], pfin, pfout;
142			int pid;
143			/* load and close persist file */
144			nr = read(persistfd, buf, sizeof(buf));
145			pfdetach();
146			if (nr < 0)
147			error(SYSTEM, "cannot read persist file");
148			buf[nr] = '\0';
149			if ((cp = index(buf, '\n')) == NULL)
150			goto formerr;
151			*cp++ = '\0';
152			if ((pid = atoi(buf)) <= 0)
153			goto formerr;
154			pfin = cp;
155			if ((cp = index(cp, '\n')) == NULL)
156			goto formerr;
157			*cp++ = '\0';
158			pfout = cp;
159			if ((cp = index(cp, '\n')) == NULL)
160			goto formerr;
161			*cp++ = '\0';
162			if (cp-buf != nr)
163			goto formerr;
164			/* wake up rendering process */
165	greg	2.2	if (kill(pid, SIGIO) < 0)
166	greg	2.1	error(SYSTEM, "cannot signal rendering process in io_process");
167			pid = fork(); /* fork i/o process */
168			if (pid < 0)
169			error(SYSTEM, "fork failed in io_process");
170			/* connect to appropriate pipe */
171			if (pid) { /* parent passes renderer output */
172			if (freopen(pfout, "r", stdin) == NULL)
173			error(SYSTEM, "cannot open input pipe in io_process");
174			} else { /* child passes renderer input */
175			if (freopen(pfin, "w", stdout) == NULL)
176			error(SYSTEM, "cannot open input pipe in io_process");
177			}
178			/* pass input to output */
179			cp = buf; n = sizeof(buf);
180			while ((nr = read(fileno(stdin), cp, n)) > 0) {
181			nr += cp-buf;
182			if ((n = write(fileno(stdout), buf, nr)) <= 0)
183			error(SYSTEM, "write error in io_process");
184			cp = buf;
185			while (n < nr)
186			*cp++ = buf[n++];
187			n = sizeof(buf) - (cp-buf);
188			}
189			fclose(stdin);
190			fclose(stdout);
191			if (pid) /* parent waits for child */
192			wait(0);
193			exit(0); /* all done, exit (not quit!) */
194			formerr:
195			error(USER, "format error in persist file");
196			}