mirror of
https://github.com/ioacademy-jikim/debugging
synced 2025-06-08 00:16:11 +00:00
77 lines
1.4 KiB
C
77 lines
1.4 KiB
C
/* -*- mode: C; c-basic-offset: 3; -*- */
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#include <assert.h>
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#include <elf.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/ptrace.h>
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#include <sys/types.h>
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#include <sys/uio.h>
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#include <sys/user.h>
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#include <sys/wait.h>
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static int
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err_out(const char *msg)
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{
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perror(msg);
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return 1;
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}
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static int
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non_empty(const char *buf, size_t len)
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{
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size_t i;
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int c = 0;
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volatile const char *p = buf;
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for (i = 0; i != len; i++)
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c |= p[i];
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return c;
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}
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static int
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do_child(void)
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{
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if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) == -1)
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return err_out("ptrace traceme");
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raise(SIGUSR1);
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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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char buf[1024];
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struct iovec iov;
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pid_t cpid, pid;
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int status;
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cpid = fork();
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if (cpid == -1)
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return err_out("fork");
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if (cpid == 0)
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return do_child();
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pid = wait(&status);
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if (pid == -1)
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return err_out("wait");
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/* Intentionally provide an uninitialized buffer to ptrace. */
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iov.iov_len = sizeof(buf);
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iov.iov_base = buf;
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if (ptrace(0x4204, cpid, NT_PRSTATUS, &iov) == -1)
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return err_out("ptrace getregset");
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assert(iov.iov_base == buf);
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assert(iov.iov_len > 0 && iov.iov_len < sizeof(buf));
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/* We're assuming here that NT_PRSTATUS never contains
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all-zeros. */
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assert(non_empty(buf, iov.iov_len));
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puts("OK");
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return 0;
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}
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