91 lines
1.7 KiB
C
91 lines
1.7 KiB
C
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/*
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#progos: linux
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#output: got: a\nthen: bc\nexit: 0\n
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*/
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/* This is a very limited subset of what ex1.c does; we just check that
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thread creation (clone syscall) and pipe writes and reads work. */
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sched.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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int pip[2];
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int
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process (void *arg)
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{
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char *s = arg;
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if (write (pip[1], s+2, 1) != 1) abort ();
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if (write (pip[1], s+1, 1) != 1) abort ();
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if (write (pip[1], s, 1) != 1) abort ();
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return 0;
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}
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int
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main (void)
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{
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int retcode;
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int pid;
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int st;
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long stack[16384];
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char buf[10] = {0};
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retcode = pipe (pip);
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if (retcode != 0)
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{
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fprintf (stderr, "Bad pipe %d\n", retcode);
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abort ();
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}
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pid = clone (process, (char *) stack + sizeof (stack) - 64,
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(CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND)
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| SIGCHLD, "cba");
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if (pid <= 0)
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{
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fprintf (stderr, "Bad clone %d\n", pid);
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abort ();
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}
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if ((retcode = read (pip[0], buf, 1)) != 1)
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{
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fprintf (stderr, "Bad read 1: %d\n", retcode);
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abort ();
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}
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printf ("got: %c\n", buf[0]);
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retcode = read (pip[0], buf, 2);
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if (retcode == 1)
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{
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retcode = read (pip[0], buf+1, 1);
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if (retcode != 1)
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{
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fprintf (stderr, "Bad read 1.5: %d\n", retcode);
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abort ();
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}
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retcode = 2;
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}
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if (retcode != 2)
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{
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fprintf (stderr, "Bad read 2: %d\n", retcode);
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abort ();
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}
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printf ("then: %s\n", buf);
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retcode = wait4 (-1, &st, WNOHANG | __WCLONE, NULL);
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if (retcode != pid || !WIFEXITED (st))
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{
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fprintf (stderr, "Bad wait %d %x\n", retcode, st);
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abort ();
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}
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printf ("exit: %d\n", WEXITSTATUS (st));
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return 0;
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}
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