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1 #include <iostream> |
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2 #include <unistd.h> |
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3 #include <spawn.h> |
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4 #include <cstring> |
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5 #include <cerrno> |
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6 #include <string> |
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7 #include <sys/wait.h> |
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8 #include "process.h" |
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9 extern char** environ; |
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10 std::string run_piped(char* const argv[], const std::string& input) |
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11 { |
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12 int status; |
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13 pid_t pid; |
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14 int pipeA[2]; |
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15 int pipeB[2]; |
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16 if (pipe(pipeA) < 0) |
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17 return "error"; |
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18 if (pipe(pipeB) < 0) |
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19 return "error"; |
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20 posix_spawn_file_actions_t actions; |
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21 posix_spawn_file_actions_init(&actions); // initialize actions |
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22 posix_spawn_file_actions_adddup2(&actions, pipeA[0], STDIN_FILENO); |
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23 posix_spawn_file_actions_adddup2(&actions, pipeB[1], STDOUT_FILENO); |
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24 posix_spawn_file_actions_addclose(&actions, pipeA[1]); // closes write end in child |
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25 posix_spawn_file_actions_addclose(&actions, pipeB[0]); // makes sure child doesn't read its own output pipe |
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26 posix_spawn_file_actions_addclose(&actions, pipeA[0]); // close read fd in child |
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27 posix_spawn_file_actions_addclose(&actions, pipeB[1]); // close read fd in child, part 2 |
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28 status = posix_spawnp(&pid, argv[0], &actions, NULL, const_cast<char* const*>(argv), environ); |
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29 close(pipeA[0]); |
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30 close(pipeB[1]); |
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31 if (status != 0) { |
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32 posix_spawn_file_actions_destroy(&actions); |
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33 close(pipeA[1]); |
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34 close(pipeB[0]); |
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35 std::cerr << "posix_spawnp failed for " << argv[0] << ": " << strerror(status) << std::endl; |
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36 return "error"; |
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37 } |
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38 size_t total_written = 0; |
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39 while (total_written < input.size()) { |
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40 ssize_t n = write(pipeA[1], input.c_str() + total_written, input.size() - total_written); |
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41 if (n < 0) { |
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42 if (errno == EINTR) { |
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43 continue; // interrupted |
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44 } |
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45 perror("write"); |
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46 break; // error, give up |
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47 } |
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48 total_written += n; |
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49 } |
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50 close(pipeA[1]); |
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51 char buf[256]; |
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52 std::string result; |
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53 ssize_t n; |
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54 while ((n = read(pipeB[0], buf, sizeof(buf))) > 0) { |
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55 result.append(buf, n); |
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56 } |
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57 close(pipeB[0]); |
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58 if (waitpid(pid, &status, 0) == -1) { |
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59 posix_spawn_file_actions_destroy(&actions); |
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60 close(pipeA[1]); |
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61 close(pipeB[0]); |
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62 perror("waitpid"); |
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63 return "error"; |
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64 } |
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65 posix_spawn_file_actions_destroy(&actions); |
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66 return result; |
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67 } |
