229 lines
		
	
	
		
			6.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			229 lines
		
	
	
		
			6.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0
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/*
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 * A ptrace test for testing PTRACE_SYSEMU, PTRACE_SETREGS and
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 * PTRACE_GETREG.  This test basically create a child process that executes
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 * syscalls and the parent process check if it is being traced appropriated.
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 *
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 * This test is heavily based on tools/testing/selftests/x86/ptrace_syscall.c
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 * test, and it was adapted to run on Powerpc by
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 * Breno Leitao <leitao@debian.org>
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 */
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#define _GNU_SOURCE
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#include <sys/ptrace.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <sys/syscall.h>
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#include <sys/user.h>
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#include <unistd.h>
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#include <errno.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <err.h>
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#include <string.h>
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#include <sys/auxv.h>
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#include "utils.h"
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/* Bitness-agnostic defines for user_regs_struct fields. */
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#define user_syscall_nr	gpr[0]
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#define user_arg0		gpr[3]
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#define user_arg1		gpr[4]
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#define user_arg2		gpr[5]
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#define user_arg3		gpr[6]
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#define user_arg4		gpr[7]
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#define user_arg5		gpr[8]
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#define user_ip		nip
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#define PTRACE_SYSEMU		0x1d
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static int nerrs;
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static void wait_trap(pid_t chld)
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{
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	siginfo_t si;
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	if (waitid(P_PID, chld, &si, WEXITED|WSTOPPED) != 0)
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		err(1, "waitid");
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	if (si.si_pid != chld)
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		errx(1, "got unexpected pid in event\n");
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	if (si.si_code != CLD_TRAPPED)
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		errx(1, "got unexpected event type %d\n", si.si_code);
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}
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static void test_ptrace_syscall_restart(void)
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{
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	int status;
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	struct pt_regs regs;
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	pid_t chld;
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	printf("[RUN]\tptrace-induced syscall restart\n");
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	chld = fork();
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	if (chld < 0)
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		err(1, "fork");
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	/*
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	 * Child process is running 4 syscalls after ptrace.
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	 *
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	 * 1) getpid()
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	 * 2) gettid()
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	 * 3) tgkill() -> Send SIGSTOP
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	 * 4) gettid() -> Where the tests will happen essentially
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	 */
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	if (chld == 0) {
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		if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
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			err(1, "PTRACE_TRACEME");
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		pid_t pid = getpid(), tid = syscall(SYS_gettid);
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		printf("\tChild will make one syscall\n");
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		syscall(SYS_tgkill, pid, tid, SIGSTOP);
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		syscall(SYS_gettid, 10, 11, 12, 13, 14, 15);
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		_exit(0);
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	}
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	/* Parent process below */
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	/* Wait for SIGSTOP sent by tgkill above. */
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	if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
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		err(1, "waitpid");
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	printf("[RUN]\tSYSEMU\n");
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	if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
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		err(1, "PTRACE_SYSEMU");
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	wait_trap(chld);
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	if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
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		err(1, "PTRACE_GETREGS");
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	/*
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	 * Ptrace trapped prior to executing the syscall, thus r3 still has
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	 * the syscall number instead of the sys_gettid() result
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	 */
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	if (regs.user_syscall_nr != SYS_gettid ||
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	    regs.user_arg0 != 10 || regs.user_arg1 != 11 ||
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	    regs.user_arg2 != 12 || regs.user_arg3 != 13 ||
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	    regs.user_arg4 != 14 || regs.user_arg5 != 15) {
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		printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n",
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			(unsigned long)regs.user_syscall_nr,
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			(unsigned long)regs.user_arg0,
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			(unsigned long)regs.user_arg1,
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			(unsigned long)regs.user_arg2,
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			(unsigned long)regs.user_arg3,
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			(unsigned long)regs.user_arg4,
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			(unsigned long)regs.user_arg5);
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		 nerrs++;
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	} else {
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		printf("[OK]\tInitial nr and args are correct\n"); }
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	printf("[RUN]\tRestart the syscall (ip = 0x%lx)\n",
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	       (unsigned long)regs.user_ip);
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	/*
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	 * Rewind to retry the same syscall again. This will basically test
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	 * the rewind process together with PTRACE_SETREGS and PTRACE_GETREGS.
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	 */
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	regs.user_ip -= 4;
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	if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0)
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		err(1, "PTRACE_SETREGS");
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	if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
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		err(1, "PTRACE_SYSEMU");
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	wait_trap(chld);
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	if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
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		err(1, "PTRACE_GETREGS");
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	if (regs.user_syscall_nr != SYS_gettid ||
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	    regs.user_arg0 != 10 || regs.user_arg1 != 11 ||
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	    regs.user_arg2 != 12 || regs.user_arg3 != 13 ||
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	    regs.user_arg4 != 14 || regs.user_arg5 != 15) {
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		printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n",
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			(unsigned long)regs.user_syscall_nr,
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			(unsigned long)regs.user_arg0,
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			(unsigned long)regs.user_arg1,
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			(unsigned long)regs.user_arg2,
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			(unsigned long)regs.user_arg3,
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			(unsigned long)regs.user_arg4,
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			(unsigned long)regs.user_arg5);
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		nerrs++;
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	} else {
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		printf("[OK]\tRestarted nr and args are correct\n");
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	}
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	printf("[RUN]\tChange nr and args and restart the syscall (ip = 0x%lx)\n",
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	       (unsigned long)regs.user_ip);
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	/*
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	 * Inject a new syscall (getpid) in the same place the previous
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	 * syscall (gettid), rewind and re-execute.
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	 */
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	regs.user_syscall_nr = SYS_getpid;
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	regs.user_arg0 = 20;
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	regs.user_arg1 = 21;
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	regs.user_arg2 = 22;
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	regs.user_arg3 = 23;
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	regs.user_arg4 = 24;
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	regs.user_arg5 = 25;
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	regs.user_ip -= 4;
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	if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0)
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		err(1, "PTRACE_SETREGS");
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	if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
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		err(1, "PTRACE_SYSEMU");
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	wait_trap(chld);
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	if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
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		err(1, "PTRACE_GETREGS");
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	/* Check that ptrace stopped at the new syscall that was
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	 * injected, and guarantee that it haven't executed, i.e, user_args
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	 * contain the arguments and not the syscall return value, for
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	 * instance.
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	 */
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	if (regs.user_syscall_nr != SYS_getpid
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		|| regs.user_arg0 != 20 || regs.user_arg1 != 21
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		|| regs.user_arg2 != 22 || regs.user_arg3 != 23
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		|| regs.user_arg4 != 24 || regs.user_arg5 != 25) {
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		printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n",
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			(unsigned long)regs.user_syscall_nr,
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			(unsigned long)regs.user_arg0,
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			(unsigned long)regs.user_arg1,
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			(unsigned long)regs.user_arg2,
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			(unsigned long)regs.user_arg3,
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			(unsigned long)regs.user_arg4,
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			(unsigned long)regs.user_arg5);
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		nerrs++;
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	} else {
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		printf("[OK]\tReplacement nr and args are correct\n");
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	}
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	if (ptrace(PTRACE_CONT, chld, 0, 0) != 0)
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		err(1, "PTRACE_CONT");
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	if (waitpid(chld, &status, 0) != chld)
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		err(1, "waitpid");
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	/* Guarantee that the process executed properly, returning 0 */
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	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
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		printf("[FAIL]\tChild failed\n");
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		nerrs++;
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	} else {
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		printf("[OK]\tChild exited cleanly\n");
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	}
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}
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int ptrace_syscall(void)
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{
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	test_ptrace_syscall_restart();
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	return nerrs;
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}
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int main(void)
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{
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	return test_harness(ptrace_syscall, "ptrace_syscall");
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}
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