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>

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 */
}


sig_noop() {}


pfhold()                /* holding pattern for idle rendering process */
{
        char    buf[128];
        register int    n;
                                /* close input and output descriptors */
        close(fileno(stdin));
        fflush(stdout);
        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 for someone to signal us */
        signal(SIGALRM, sig_noop);
        pflock(0);
        pause();
        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, SIGALRM) < 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:	2.1
Committed:	Wed Jan 20 15:19:00 1993 UTC (31 years, 3 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Log Message:	Initial revision
#	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			extern char strcpy(), index();
18
19			extern int headismine; /* boolean true if header belongs to me */
20
21			static char persistfname = NULL; / persist file name */
22			static int persistfd = -1; /* persist file descriptor */
23
24			static char inpname[TEMPLEN+1], outpname[TEMPLEN+1];
25
26
27			pfdetach() /* release persist (and header) resources */
28			{
29			if (persistfd >= 0)
30			close(persistfd);
31			persistfd = -1;
32			persistfname = NULL;
33			inpname[0] = '\0';
34			outpname[0] = '\0';
35			headismine = 0;
36			}
37
38
39			pfclean() /* clean up persist files */
40			{
41			if (persistfd >= 0)
42			close(persistfd);
43			if (persistfname != NULL)
44			unlink(persistfname);
45			if (inpname[0])
46			unlink(inpname);
47			if (outpname[0])
48			unlink(outpname);
49			}
50
51
52			pflock(lf) /* place or release exclusive lock on file */
53			int lf;
54			{
55			struct flock fls;
56
57			fls.l_type = lf ? F_WRLCK : F_UNLCK;
58			fls.l_whence = 0;
59			fls.l_start = 0L;
60			fls.l_len = 0L;
61			if (fcntl(persistfd, F_SETLKW, &fls) < 0)
62			error(SYSTEM, "cannot (un)lock persist file");
63			}
64
65
66			persistfile(pfn) /* open persist file and lock it */
67			char *pfn;
68			{
69			persistfd = open(pfn, O_WRONLY\|O_CREAT\|O_EXCL, 0666);
70			if (persistfd >= 0) {
71			persistfname = pfn;
72			pflock(1);
73			return;
74			}
75			/* file exists -- switch to i/o process */
76			persistfd = open(pfn, O_RDWR);
77			if (persistfd < 0) {
78			sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
79			error(SYSTEM, errmsg);
80			}
81			pflock(1);
82			io_process(); /* never returns */
83			}
84
85
86			sig_noop() {}
87
88
89			pfhold() /* holding pattern for idle rendering process */
90			{
91			char buf[128];
92			register int n;
93			/* close input and output descriptors */
94			close(fileno(stdin));
95			fflush(stdout);
96			close(fileno(stdout));
97			/* create named pipes for input and output */
98			if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO\|0600) < 0)
99			goto createrr;
100			if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO\|0600) < 0)
101			goto createrr;
102			sprintf(buf, "%d\n%s\n%s\n", getpid(), inpname, outpname);
103			if (lseek(persistfd, 0L, 0) < 0)
104			error(SYSTEM, "seek error on persist file in pfhold");
105			n = strlen(buf);
106			if (write(persistfd, buf, n) < n)
107			error(SYSTEM, "error writing persist file in pfhold");
108			/* wait for someone to signal us */
109			signal(SIGALRM, sig_noop);
110			pflock(0);
111			pause();
112			pflock(1);
113			/* someone wants us; reopen stdin and stdout */
114			if (freopen(inpname, "r", stdin) == NULL)
115			goto openerr;
116			if (freopen(outpname, "w", stdout) == NULL)
117			goto openerr;
118			unlink(inpname);
119			inpname[0] = '\0';
120			unlink(outpname);
121			outpname[0] = '\0';
122			return;
123			createrr:
124			error(SYSTEM, "cannot create named pipes in pfhold");
125			openerr:
126			error(SYSTEM, "cannot open named pipes in pfhold");
127			}
128
129
130			io_process() /* just act as conduits to and from actual process */
131			{
132			register char *cp;
133			register int nr, n;
134			char buf[4096], pfin, pfout;
135			int pid;
136			/* load and close persist file */
137			nr = read(persistfd, buf, sizeof(buf));
138			pfdetach();
139			if (nr < 0)
140			error(SYSTEM, "cannot read persist file");
141			buf[nr] = '\0';
142			if ((cp = index(buf, '\n')) == NULL)
143			goto formerr;
144			*cp++ = '\0';
145			if ((pid = atoi(buf)) <= 0)
146			goto formerr;
147			pfin = cp;
148			if ((cp = index(cp, '\n')) == NULL)
149			goto formerr;
150			*cp++ = '\0';
151			pfout = cp;
152			if ((cp = index(cp, '\n')) == NULL)
153			goto formerr;
154			*cp++ = '\0';
155			if (cp-buf != nr)
156			goto formerr;
157			/* wake up rendering process */
158			if (kill(pid, SIGALRM) < 0)
159			error(SYSTEM, "cannot signal rendering process in io_process");
160			pid = fork(); /* fork i/o process */
161			if (pid < 0)
162			error(SYSTEM, "fork failed in io_process");
163			/* connect to appropriate pipe */
164			if (pid) { /* parent passes renderer output */
165			if (freopen(pfout, "r", stdin) == NULL)
166			error(SYSTEM, "cannot open input pipe in io_process");
167			} else { /* child passes renderer input */
168			if (freopen(pfin, "w", stdout) == NULL)
169			error(SYSTEM, "cannot open input pipe in io_process");
170			}
171			/* pass input to output */
172			cp = buf; n = sizeof(buf);
173			while ((nr = read(fileno(stdin), cp, n)) > 0) {
174			nr += cp-buf;
175			if ((n = write(fileno(stdout), buf, nr)) <= 0)
176			error(SYSTEM, "write error in io_process");
177			cp = buf;
178			while (n < nr)
179			*cp++ = buf[n++];
180			n = sizeof(buf) - (cp-buf);
181			}
182			fclose(stdin);
183			fclose(stdout);
184			if (pid) /* parent waits for child */
185			wait(0);
186			exit(0); /* all done, exit (not quit!) */
187			formerr:
188			error(USER, "format error in persist file");
189			}