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#ifndef lint |
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static const char RCSid[] = "$Id$"; |
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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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* External symbols declared in standard.h |
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*/ |
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|
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#include "copyright.h" |
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|
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/* find pipe buffer limit */ |
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#include <sys/param.h> |
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|
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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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|
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#include "vfork.h" |
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|
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#ifndef BSD |
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#include <errno.h> |
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#endif |
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|
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|
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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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|
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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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|
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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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|
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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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|
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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 = 0, nrem = siz; |
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retry: |
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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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#ifndef BSD |
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if (errno == EINTR) /* we were interrupted! */ |
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goto retry; |
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#endif |
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return(cc); |
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} |
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return(siz-nrem); |
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} |
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|
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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 = 0, nrem = siz; |
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retry: |
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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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#ifndef BSD |
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if (errno == EINTR) /* we were interrupted! */ |
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goto retry; |
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#endif |
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return(cc); |
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} |
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return(siz-nrem); |
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} |
