1 //===-- ExecuteFunction implementation for Unix-like Systems --------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "ExecuteFunction.h"
10 #include <cassert>
11 #include <cstdlib>
12 #include <cstring>
13 #include <iostream>
14 #include <memory>
15 #include <poll.h>
16 #include <signal.h>
17 #include <sys/wait.h>
18 #include <unistd.h>
19 
20 namespace __llvm_libc {
21 namespace testutils {
22 
23 bool ProcessStatus::exited_normally() const {
24   return WIFEXITED(platform_defined);
25 }
26 
27 int ProcessStatus::get_exit_code() const {
28   assert(exited_normally() && "Abnormal termination, no exit code");
29   return WEXITSTATUS(platform_defined);
30 }
31 
32 int ProcessStatus::get_fatal_signal() const {
33   if (exited_normally())
34     return 0;
35   return WTERMSIG(platform_defined);
36 }
37 
38 ProcessStatus invoke_in_subprocess(FunctionCaller *func, unsigned timeout_ms) {
39   std::unique_ptr<FunctionCaller> X(func);
40   int pipe_fds[2];
41   if (::pipe(pipe_fds) == -1)
42     return ProcessStatus::error("pipe(2) failed");
43 
44   // Don't copy the buffers into the child process and print twice.
45   std::cout.flush();
46   std::cerr.flush();
47   pid_t pid = ::fork();
48   if (pid == -1)
49     return ProcessStatus::error("fork(2) failed");
50 
51   if (!pid) {
52     (*func)();
53     std::exit(0);
54   }
55   ::close(pipe_fds[1]);
56 
57   struct pollfd poll_fd {
58     pipe_fds[0], 0, 0
59   };
60   // No events requested so this call will only return after the timeout or if
61   // the pipes peer was closed, signaling the process exited.
62   if (::poll(&poll_fd, 1, timeout_ms) == -1)
63     return ProcessStatus::error("poll(2) failed");
64   // If the pipe wasn't closed by the child yet then timeout has expired.
65   if (!(poll_fd.revents & POLLHUP)) {
66     ::kill(pid, SIGKILL);
67     return ProcessStatus::timed_out_ps();
68   }
69 
70   int wstatus = 0;
71   // Wait on the pid of the subprocess here so it gets collected by the system
72   // and doesn't turn into a zombie.
73   pid_t status = ::waitpid(pid, &wstatus, 0);
74   if (status == -1)
75     return ProcessStatus::error("waitpid(2) failed");
76   assert(status == pid);
77   return {wstatus};
78 }
79 
80 const char *signal_as_string(int signum) { return ::strsignal(signum); }
81 
82 } // namespace testutils
83 } // namespace __llvm_libc
84