92 lines
1.7 KiB
C
92 lines
1.7 KiB
C
#include <u.h>
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#include <lib9.h>
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#include <bio.h>
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#include "awk.h"
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#define MAXFORKS 20
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#define NSYSFILE 3
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#define tst(a,b) (mode == OREAD? (b) : (a))
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#define RDR 0
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#define WTR 1
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struct a_fork {
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short done;
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short fd;
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int pid;
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char status[128];
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};
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static struct a_fork the_fork[MAXFORKS];
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Biobuf*
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popen(char *cmd, int mode)
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{
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int p[2];
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int myside, hisside, pid;
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int i, ind;
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for (ind = 0; ind < MAXFORKS; ind++)
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if (the_fork[ind].pid == 0)
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break;
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if (ind == MAXFORKS)
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return nil;
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if(pipe(p) < 0)
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return nil;
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myside = tst(p[WTR], p[RDR]);
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hisside = tst(p[RDR], p[WTR]);
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switch (pid = fork()) {
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case -1:
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return nil;
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case 0:
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/* myside and hisside reverse roles in child */
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close(myside);
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dup(hisside, tst(0, 1));
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for (i=NSYSFILE; i<FOPEN_MAX; i++)
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close(i);
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execl("/bin/rc", "rc", "-c", cmd, nil);
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exits("exec failed");
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default:
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the_fork[ind].pid = pid;
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the_fork[ind].fd = myside;
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the_fork[ind].done = 0;
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close(hisside);
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return(Bfdopen(myside, mode));
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}
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}
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int
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pclose(Biobuf *ptr)
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{
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int f, r, ind;
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Waitmsg *status;
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f = Bfildes(ptr);
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Bterm(ptr);
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for (ind = 0; ind < MAXFORKS; ind++)
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if (the_fork[ind].fd == f && the_fork[ind].pid != 0)
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break;
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if (ind == MAXFORKS)
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return -1;
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if (!the_fork[ind].done) {
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do {
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if((status = wait()) == nil)
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r = -1;
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else
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r = status->pid;
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for (f = 0; f < MAXFORKS; f++) {
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if (r == the_fork[f].pid) {
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the_fork[f].done = 1;
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strecpy(the_fork[f].status, the_fork[f].status+512, status->msg);
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break;
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}
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}
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free(status);
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} while(r != the_fork[ind].pid && r != -1);
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if(r == -1)
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strcpy(the_fork[ind].status, "No loved ones to wait for");
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}
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the_fork[ind].pid = 0;
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if(the_fork[ind].status[0] != '\0')
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return 1;
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return 0;
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}
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