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fc35ef12dc
This patch adds a new test for the new PTRACE_SYSEMU ptrace request. This test also relies on PTRACE_GETREGS and PTRACE_SETREGS requests to run properly, since the trace instruction (gettid() syscall) is being modified at run-time (by PTRACE_SETREGS) and re-executed three times. PTRACE_GETREGS is being used to check that the registers are still sane. This test basically creates a child process that executes syscalls and the parent process check if it is being traced appropriately. The parent process guarantees that the SYSCALLs are being traced, with PTRACE_SYSEMU, and ptrace stops the child application before a syscall is executed. The way the tests validates it, is by guaranteeing that the system calls arguments, as argv[0] (r3) which is the same register that will have the syscall return value on powerpc, are not being corrupted on PTRACE_SYSEMU with a return value, i.e, it continues to have the current arguments instead, meaning that the registers where not clobbered. This test is basically the same test for x86 located at tools/testing/selftests/x86/ptrace_syscall.c, limited to test PTRACE_SYSEMU request, and ported to PowerPC. Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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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