src/rt/persist.c

/* Copyright (c) 1996 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 */

extern char     *progname;      /* global program name */

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, 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 int sig_io() { got_io++; }

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


pfhold()                /* holding pattern for idle rendering process */
{
        int     (*oldalrm)();
        char    buf[512];
        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) < 0)
                goto createrr;
        if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
                goto createrr;
        sprintf(buf, "%s %d\n%s\n%s\n", progname, getpid(), inpname, outpname);
        if (lseek(persistfd, 0L, 0) < 0 || ftruncate(persistfd, 0L) < 0)
                error(SYSTEM, "seek/truncate error on persist file");
        n = strlen(buf);
        if (write(persistfd, buf, n) < n)
                error(SYSTEM, "error writing persist file");
                                /* wait TIMELIM for someone to signal us */
        got_io = 0;
        signal(SIGIO, sig_io);
        oldalrm = (int (*)())signal(SIGALRM, sig_alrm);
        alarm(TIMELIM);
        pflock(0);
        while (!got_io)
                pause();
        alarm(0);
        signal(SIGALRM, oldalrm);
        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[512], *pfin, *pfout;
        int     pid;
                                /* load and close persist file */
        sleep(5);               /* helps synchronization */
        nr = read(persistfd, buf, sizeof(buf)-1);
        pfdetach();
        if (nr <= 0)
                error(SYSTEM, "cannot read persist file");
        buf[nr] = '\0';
        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';
        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");
        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 */
                                /* read as much as we can, write all of it */
        while ((nr = read(0, cp=buf, sizeof(buf))) > 0)
                do {
                        if ((n = write(1, cp, nr)) <= 0)
                                goto writerr;
                        cp += n;
                } while ((nr -= n) > 0);
        if (nr < 0)
                error(SYSTEM, "read error in io_process");
        close(0);               /* close input */
        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:	2.13
Committed:	Thu Jul 4 09:54:59 1996 UTC (29 years, 4 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.12:	+16 -6 lines
Log Message:	made it so alarm signal causes quiet termination in persist mode fixed minor synchronization problem by adding sleep() call. (I hope!)
#	User	Rev	Content
1	greg	2.13	/* Copyright (c) 1996 Regents of the University of California */
2	greg	2.1
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	greg	2.12	extern char progname; / global program name */
29
30	greg	2.1	static char persistfname = NULL; / persist file name */
31			static int persistfd = -1; /* persist file descriptor */
32
33			static char inpname[TEMPLEN+1], outpname[TEMPLEN+1];
34
35
36			pfdetach() /* release persist (and header) resources */
37			{
38			if (persistfd >= 0)
39			close(persistfd);
40			persistfd = -1;
41			persistfname = NULL;
42			inpname[0] = '\0';
43			outpname[0] = '\0';
44			headismine = 0;
45			}
46
47
48			pfclean() /* clean up persist files */
49			{
50			if (persistfd >= 0)
51			close(persistfd);
52			if (persistfname != NULL)
53			unlink(persistfname);
54			if (inpname[0])
55			unlink(inpname);
56			if (outpname[0])
57			unlink(outpname);
58			}
59
60
61			pflock(lf) /* place or release exclusive lock on file */
62			int lf;
63			{
64			struct flock fls;
65
66			fls.l_type = lf ? F_WRLCK : F_UNLCK;
67			fls.l_whence = 0;
68			fls.l_start = 0L;
69			fls.l_len = 0L;
70			if (fcntl(persistfd, F_SETLKW, &fls) < 0)
71			error(SYSTEM, "cannot (un)lock persist file");
72			}
73
74
75			persistfile(pfn) /* open persist file and lock it */
76			char *pfn;
77			{
78	greg	2.13	persistfd = open(pfn, O_WRONLY\|O_CREAT\|O_EXCL, 0644);
79	greg	2.1	if (persistfd >= 0) {
80			persistfname = pfn;
81			pflock(1);
82			return;
83			}
84			/* file exists -- switch to i/o process */
85			persistfd = open(pfn, O_RDWR);
86			if (persistfd < 0) {
87			sprintf(errmsg, "cannot open persist file \"%s\"", pfn);
88			error(SYSTEM, errmsg);
89			}
90			pflock(1);
91			io_process(); /* never returns */
92			}
93
94
95	greg	2.13	static int got_io;
96	greg	2.1
97	greg	2.13	static int sig_io() { got_io++; }
98	greg	2.1
99	greg	2.13	static int sig_alrm() { quit(0); }
100
101
102	greg	2.1	pfhold() /* holding pattern for idle rendering process */
103			{
104	greg	2.13	int (*oldalrm)();
105	greg	2.12	char buf[512];
106	greg	2.1	register int n;
107			/* close input and output descriptors */
108			close(fileno(stdin));
109			close(fileno(stdout));
110			/* create named pipes for input and output */
111	greg	2.11	if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO\|0600, 0) < 0)
112	greg	2.1	goto createrr;
113	greg	2.11	if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO\|0600, 0) < 0)
114	greg	2.1	goto createrr;
115	greg	2.12	sprintf(buf, "%s %d\n%s\n%s\n", progname, getpid(), inpname, outpname);
116	greg	2.10	if (lseek(persistfd, 0L, 0) < 0 \|\| ftruncate(persistfd, 0L) < 0)
117			error(SYSTEM, "seek/truncate error on persist file");
118	greg	2.1	n = strlen(buf);
119			if (write(persistfd, buf, n) < n)
120	greg	2.10	error(SYSTEM, "error writing persist file");
121	greg	2.2	/* wait TIMELIM for someone to signal us */
122	greg	2.13	got_io = 0;
123			signal(SIGIO, sig_io);
124			oldalrm = (int (*)())signal(SIGALRM, sig_alrm);
125	greg	2.2	alarm(TIMELIM);
126	greg	2.1	pflock(0);
127	greg	2.13	while (!got_io)
128			pause();
129	greg	2.2	alarm(0);
130	greg	2.13	signal(SIGALRM, oldalrm);
131	greg	2.2	signal(SIGIO, SIG_DFL);
132	greg	2.1	pflock(1);
133			/* someone wants us; reopen stdin and stdout */
134			if (freopen(inpname, "r", stdin) == NULL)
135			goto openerr;
136			if (freopen(outpname, "w", stdout) == NULL)
137			goto openerr;
138			unlink(inpname);
139			inpname[0] = '\0';
140			unlink(outpname);
141			outpname[0] = '\0';
142			return;
143			createrr:
144			error(SYSTEM, "cannot create named pipes in pfhold");
145			openerr:
146			error(SYSTEM, "cannot open named pipes in pfhold");
147			}
148
149
150			io_process() /* just act as conduits to and from actual process */
151			{
152			register char *cp;
153			register int nr, n;
154	greg	2.12	char buf[512], pfin, pfout;
155	greg	2.1	int pid;
156			/* load and close persist file */
157	greg	2.13	sleep(5); /* helps synchronization */
158	greg	2.12	nr = read(persistfd, buf, sizeof(buf)-1);
159	greg	2.1	pfdetach();
160	greg	2.13	if (nr <= 0)
161	greg	2.1	error(SYSTEM, "cannot read persist file");
162			buf[nr] = '\0';
163	greg	2.12	if ((cp = index(buf, ' ')) == NULL)
164	greg	2.1	goto formerr;
165			*cp++ = '\0';
166	greg	2.12	if ((pid = atoi(cp)) <= 0)
167	greg	2.1	goto formerr;
168			if ((cp = index(cp, '\n')) == NULL)
169			goto formerr;
170	greg	2.12	pfin = ++cp;
171			if ((cp = index(cp, '\n')) == NULL)
172			goto formerr;
173	greg	2.1	*cp++ = '\0';
174			pfout = cp;
175			if ((cp = index(cp, '\n')) == NULL)
176			goto formerr;
177			*cp++ = '\0';
178			if (cp-buf != nr)
179			goto formerr;
180	greg	2.12	if (strcmp(buf, progname)) {
181			sprintf(errmsg, "persist file for %s, not %s", buf, progname);
182			error(USER, errmsg);
183			}
184	greg	2.1	/* wake up rendering process */
185	greg	2.2	if (kill(pid, SIGIO) < 0)
186	greg	2.1	error(SYSTEM, "cannot signal rendering process in io_process");
187			pid = fork(); /* fork i/o process */
188			if (pid < 0)
189			error(SYSTEM, "fork failed in io_process");
190			/* connect to appropriate pipe */
191			if (pid) { /* parent passes renderer output */
192	greg	2.7	close(0);
193			if (open(pfout, O_RDONLY) != 0)
194	greg	2.1	error(SYSTEM, "cannot open input pipe in io_process");
195			} else { /* child passes renderer input */
196	greg	2.7	close(1);
197			if (open(pfin, O_WRONLY) != 1)
198			error(SYSTEM, "cannot open output pipe in io_process");
199	greg	2.1	}
200			/* pass input to output */
201	greg	2.9	/* read as much as we can, write all of it */
202			while ((nr = read(0, cp=buf, sizeof(buf))) > 0)
203			do {
204			if ((n = write(1, cp, nr)) <= 0)
205			goto writerr;
206			cp += n;
207			} while ((nr -= n) > 0);
208	greg	2.7	if (nr < 0)
209			error(SYSTEM, "read error in io_process");
210			close(0); /* close input */
211			close(1); /* close output */
212	greg	2.1	if (pid) /* parent waits for child */
213			wait(0);
214			exit(0); /* all done, exit (not quit!) */
215			formerr:
216			error(USER, "format error in persist file");
217	greg	2.7	writerr:
218			error(SYSTEM, "write error in io_process");
219	greg	2.1	}
220	greg	2.6
221	greg	2.8	#else
222
223			pfclean() {}
224
225	greg	2.6	#endif