63 lines
1.2 KiB
C
63 lines
1.2 KiB
C
#include <stdio.h>
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#include <signal.h>
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#define tst(a,b) (*mode == 'r'? (b) : (a))
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#define RDR 0
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#define WTR 1
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extern FILE *fdopen();
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extern int execl(), fork(), pipe(), close(), fcntl();
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static int popen_pid[20];
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FILE *
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popen(cmd, mode)
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char *cmd, *mode;
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{
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int p[2];
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register int myside, yourside, pid;
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if(pipe(p) < 0)
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return(NULL);
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myside = tst(p[WTR], p[RDR]);
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yourside = tst(p[RDR], p[WTR]);
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if((pid = fork()) == 0) {
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/* myside and yourside reverse roles in child */
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int stdio;
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stdio = tst(0, 1);
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(void) close(myside);
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(void) close(stdio);
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(void) fcntl(yourside, 0, stdio);
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(void) close(yourside);
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(void) execl("/bin/sh", "sh", "-c", cmd, NULL);
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_exit(1);
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}
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if(pid == -1)
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return(NULL);
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popen_pid[myside] = pid;
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(void) close(yourside);
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return(fdopen(myside, mode));
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}
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int
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pclose(ptr)
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FILE *ptr;
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{
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register int f, r;
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int status, (*hstat)(), (*istat)(), (*qstat)();
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f = fileno(ptr);
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(void) fclose(ptr);
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istat = signal(SIGINT, SIG_IGN);
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qstat = signal(SIGQUIT, SIG_IGN);
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hstat = signal(SIGHUP, SIG_IGN);
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while((r = wait(&status)) != popen_pid[f] && r != -1)
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;
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if(r == -1)
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status = -1;
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(void) signal(SIGINT, istat);
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(void) signal(SIGQUIT, qstat);
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(void) signal(SIGHUP, hstat);
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return(status);
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}
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