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/* Copyright (c) 1991 Regents of the University of California */
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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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* Routines to communicate with separate process via dual pipes
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*/
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/* find pipe buffer limit */
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#include <sys/param.h>
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#ifndef PIPE_BUF
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#ifdef PIPSIZ
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#define PIPE_BUF PIPSIZ
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#else
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#ifdef PIPE_MAX
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#define PIPE_BUF PIPE_MAX
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#else
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#define PIPE_BUF 512 /* hyperconservative */
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#endif
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#endif
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#endif
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#include "vfork.h"
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int
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open_process(pd, av) /* open communication to separate process */
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int pd[3];
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char *av[];
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{
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extern char *getpath(), *getenv();
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char *compath;
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int p0[2], p1[2];
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/* find executable */
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compath = getpath(av[0], getenv("PATH"), 1);
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if (compath == 0)
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return(0);
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if (pipe(p0) < 0 || pipe(p1) < 0)
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return(-1);
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if ((pd[2] = vfork()) == 0) { /* if child */
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close(p0[1]);
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close(p1[0]);
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if (p0[0] != 0) { /* connect p0 to stdin */
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dup2(p0[0], 0);
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close(p0[0]);
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}
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if (p1[1] != 1) { /* connect p1 to stdout */
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dup2(p1[1], 1);
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close(p1[1]);
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}
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execv(compath, av); /* exec command */
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perror(compath);
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_exit(127);
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}
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if (pd[2] == -1)
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return(-1);
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close(p0[0]);
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close(p1[1]);
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pd[0] = p1[0];
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pd[1] = p0[1];
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return(PIPE_BUF);
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}
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int
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process(pd, recvbuf, sendbuf, nbr, nbs) /* process data through pd */
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int pd[3];
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char *recvbuf, *sendbuf;
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int nbr, nbs;
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{
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if (nbs > PIPE_BUF)
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return(-1);
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if (writebuf(pd[1], sendbuf, nbs) < nbs)
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return(-1);
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return(readbuf(pd[0], recvbuf, nbr));
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}
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int
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close_process(pd) /* close pipes and wait for process */
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int pd[3];
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{
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int pid, status;
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close(pd[1]);
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close(pd[0]);
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while ((pid = wait(&status)) != -1)
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if (pid == pd[2])
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return(status>>8 & 0xff);
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return(-1); /* ? unknown status */
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}
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int
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readbuf(fd, bpos, siz) /* read all of requested buffer */
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int fd;
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char *bpos;
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int siz;
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{
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register int cc, nrem = siz;
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while (nrem > 0 && (cc = read(fd, bpos, nrem)) > 0) {
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bpos += cc;
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nrem -= cc;
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}
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if (cc < 0)
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return(cc);
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return(siz-nrem);
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}
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int
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writebuf(fd, bpos, siz) /* write all of requested buffer */
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int fd;
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char *bpos;
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int siz;
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{
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register int cc, nrem = siz;
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while (nrem > 0 && (cc = write(fd, bpos, nrem)) > 0) {
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bpos += cc;
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nrem -= cc;
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}
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if (cc < 0)
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return(cc);
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return(siz-nrem);
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}
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