jD91mZM2
84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
#include <signal.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <sys/ptrace.h>
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#include <sys/user.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include "test_helpers.h"
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#ifdef __linux__
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const int SYS_write = 1;
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#endif
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#ifdef __redox__
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const int SYS_write = 0x21000004;
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#endif
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int main() {
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int pid = fork();
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ERROR_IF(fork, pid, == -1);
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if (pid == 0) {
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// Test behavior on Redox when TRACEME hasn't been activated
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// before waitpid is invoked!
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sleep(1);
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int result = ptrace(PTRACE_TRACEME, 0, NULL, NULL);
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ERROR_IF(ptrace, result, == -1);
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UNEXP_IF(ptrace, result, != 0);
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// Alert parent: I'm ready
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result = raise(SIGSTOP);
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ERROR_IF(raise, result, == -1);
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UNEXP_IF(raise, result, != 0);
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puts("This is printed to STDOUT.");
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puts("Or, at least, that's what I thought.");
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puts("But all write(...) syscalls are actually redirected to STDERR by the tracer.");
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puts("Big surprise, right!");
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} else {
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// Wait for child process to be ready
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int result = waitpid(pid, NULL, 0);
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ERROR_IF(waitpid, result, == -1);
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int status;
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while (true) {
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puts("----- Pre-syscall -----");
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result = ptrace(PTRACE_SYSCALL, pid, NULL, NULL);
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ERROR_IF(ptrace, result, == -1);
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UNEXP_IF(ptrace, result, != 0);
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puts("Wait...");
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result = waitpid(pid, &status, 0);
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ERROR_IF(waitpid, result, == -1);
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if (WIFEXITED(status)) { break; }
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struct user_regs_struct regs;
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puts("Get regs");
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result = ptrace(PTRACE_GETREGS, pid, NULL, ®s);
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ERROR_IF(ptrace, result, == -1);
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if (regs.orig_rax == SYS_write || regs.orig_rax == SYS_write) {
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regs.rdi = 2;
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puts("Set regs");
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result = ptrace(PTRACE_SETREGS, pid, NULL, ®s);
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ERROR_IF(ptrace, result, == -1);
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}
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puts("Post-syscall");
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result = ptrace(PTRACE_SYSCALL, pid, NULL, NULL);
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ERROR_IF(ptrace, result, == -1);
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UNEXP_IF(ptrace, result, != 0);
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puts("Wait...");
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result = waitpid(pid, &status, 0);
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ERROR_IF(waitpid, result, == -1);
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if (WIFEXITED(status)) { break; }
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}
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printf("Child exited with status %d\n", WEXITSTATUS(status));
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}
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}
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