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/* Copyright (c) 1993 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* Routines for persistent rtrace and rpict processes. |
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*/ |
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|
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#include "standard.h" |
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#include "paths.h" |
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#include <signal.h> |
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#include <sys/types.h> |
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#include <sys/stat.h> |
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|
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extern char *strcpy(), *index(); |
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|
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extern int headismine; /* boolean true if header belongs to me */ |
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|
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static char *persistfname = NULL; /* persist file name */ |
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static int persistfd = -1; /* persist file descriptor */ |
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|
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static char inpname[TEMPLEN+1], outpname[TEMPLEN+1]; |
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|
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|
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pfdetach() /* release persist (and header) resources */ |
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{ |
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if (persistfd >= 0) |
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close(persistfd); |
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persistfd = -1; |
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persistfname = NULL; |
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inpname[0] = '\0'; |
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outpname[0] = '\0'; |
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headismine = 0; |
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} |
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|
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|
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pfclean() /* clean up persist files */ |
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{ |
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if (persistfd >= 0) |
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close(persistfd); |
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if (persistfname != NULL) |
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unlink(persistfname); |
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if (inpname[0]) |
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unlink(inpname); |
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if (outpname[0]) |
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unlink(outpname); |
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} |
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|
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|
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pflock(lf) /* place or release exclusive lock on file */ |
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int lf; |
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{ |
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struct flock fls; |
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|
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fls.l_type = lf ? F_WRLCK : F_UNLCK; |
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fls.l_whence = 0; |
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fls.l_start = 0L; |
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fls.l_len = 0L; |
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if (fcntl(persistfd, F_SETLKW, &fls) < 0) |
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error(SYSTEM, "cannot (un)lock persist file"); |
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} |
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|
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|
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persistfile(pfn) /* open persist file and lock it */ |
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char *pfn; |
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{ |
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persistfd = open(pfn, O_WRONLY|O_CREAT|O_EXCL, 0666); |
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if (persistfd >= 0) { |
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persistfname = pfn; |
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pflock(1); |
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return; |
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} |
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/* file exists -- switch to i/o process */ |
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persistfd = open(pfn, O_RDWR); |
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if (persistfd < 0) { |
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sprintf(errmsg, "cannot open persist file \"%s\"", pfn); |
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error(SYSTEM, errmsg); |
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} |
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pflock(1); |
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io_process(); /* never returns */ |
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} |
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|
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|
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sig_noop() {} |
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|
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|
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pfhold() /* holding pattern for idle rendering process */ |
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{ |
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char buf[128]; |
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register int n; |
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/* close input and output descriptors */ |
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close(fileno(stdin)); |
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fflush(stdout); |
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close(fileno(stdout)); |
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/* create named pipes for input and output */ |
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if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO|0600) < 0) |
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goto createrr; |
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if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO|0600) < 0) |
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goto createrr; |
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sprintf(buf, "%d\n%s\n%s\n", getpid(), inpname, outpname); |
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if (lseek(persistfd, 0L, 0) < 0) |
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error(SYSTEM, "seek error on persist file in pfhold"); |
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n = strlen(buf); |
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if (write(persistfd, buf, n) < n) |
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error(SYSTEM, "error writing persist file in pfhold"); |
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/* wait for someone to signal us */ |
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signal(SIGALRM, sig_noop); |
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pflock(0); |
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pause(); |
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pflock(1); |
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/* someone wants us; reopen stdin and stdout */ |
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if (freopen(inpname, "r", stdin) == NULL) |
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goto openerr; |
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if (freopen(outpname, "w", stdout) == NULL) |
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goto openerr; |
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unlink(inpname); |
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inpname[0] = '\0'; |
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unlink(outpname); |
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outpname[0] = '\0'; |
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return; |
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createrr: |
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error(SYSTEM, "cannot create named pipes in pfhold"); |
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openerr: |
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error(SYSTEM, "cannot open named pipes in pfhold"); |
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} |
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|
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|
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io_process() /* just act as conduits to and from actual process */ |
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{ |
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register char *cp; |
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register int nr, n; |
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char buf[4096], *pfin, *pfout; |
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int pid; |
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/* load and close persist file */ |
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nr = read(persistfd, buf, sizeof(buf)); |
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pfdetach(); |
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if (nr < 0) |
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error(SYSTEM, "cannot read persist file"); |
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buf[nr] = '\0'; |
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if ((cp = index(buf, '\n')) == NULL) |
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goto formerr; |
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*cp++ = '\0'; |
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if ((pid = atoi(buf)) <= 0) |
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goto formerr; |
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pfin = cp; |
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if ((cp = index(cp, '\n')) == NULL) |
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goto formerr; |
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*cp++ = '\0'; |
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pfout = cp; |
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if ((cp = index(cp, '\n')) == NULL) |
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goto formerr; |
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*cp++ = '\0'; |
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if (cp-buf != nr) |
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goto formerr; |
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/* wake up rendering process */ |
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if (kill(pid, SIGALRM) < 0) |
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error(SYSTEM, "cannot signal rendering process in io_process"); |
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pid = fork(); /* fork i/o process */ |
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if (pid < 0) |
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error(SYSTEM, "fork failed in io_process"); |
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/* connect to appropriate pipe */ |
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if (pid) { /* parent passes renderer output */ |
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if (freopen(pfout, "r", stdin) == NULL) |
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error(SYSTEM, "cannot open input pipe in io_process"); |
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} else { /* child passes renderer input */ |
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if (freopen(pfin, "w", stdout) == NULL) |
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error(SYSTEM, "cannot open input pipe in io_process"); |
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} |
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/* pass input to output */ |
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cp = buf; n = sizeof(buf); |
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while ((nr = read(fileno(stdin), cp, n)) > 0) { |
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nr += cp-buf; |
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if ((n = write(fileno(stdout), buf, nr)) <= 0) |
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error(SYSTEM, "write error in io_process"); |
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cp = buf; |
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while (n < nr) |
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*cp++ = buf[n++]; |
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n = sizeof(buf) - (cp-buf); |
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} |
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fclose(stdin); |
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fclose(stdout); |
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if (pid) /* parent waits for child */ |
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wait(0); |
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exit(0); /* all done, exit (not quit!) */ |
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formerr: |
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error(USER, "format error in persist file"); |
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} |
