Pirama Arumuga Nainar | 7c91505 | 2015-04-08 08:58:29 -0700 | [diff] [blame] | 1 | //===-- sanitizer_symbolizer_process_libcdep.cc ---------------------------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // Implementation of SymbolizerProcess used by external symbolizers. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #include "sanitizer_platform.h" |
| 15 | #if SANITIZER_POSIX |
Pirama Arumuga Nainar | 259f706 | 2015-05-06 11:49:53 -0700 | [diff] [blame] | 16 | #include "sanitizer_posix.h" |
Pirama Arumuga Nainar | 7c91505 | 2015-04-08 08:58:29 -0700 | [diff] [blame] | 17 | #include "sanitizer_symbolizer_internal.h" |
| 18 | |
| 19 | #include <errno.h> |
| 20 | #include <stdlib.h> |
| 21 | #include <sys/wait.h> |
| 22 | #include <unistd.h> |
| 23 | |
| 24 | #if SANITIZER_MAC |
| 25 | #include <util.h> // for forkpty() |
| 26 | #endif // SANITIZER_MAC |
| 27 | |
| 28 | namespace __sanitizer { |
| 29 | |
| 30 | SymbolizerProcess::SymbolizerProcess(const char *path, bool use_forkpty) |
| 31 | : path_(path), |
| 32 | input_fd_(kInvalidFd), |
| 33 | output_fd_(kInvalidFd), |
| 34 | times_restarted_(0), |
| 35 | failed_to_start_(false), |
| 36 | reported_invalid_path_(false), |
| 37 | use_forkpty_(use_forkpty) { |
| 38 | CHECK(path_); |
| 39 | CHECK_NE(path_[0], '\0'); |
| 40 | } |
| 41 | |
| 42 | const char *SymbolizerProcess::SendCommand(const char *command) { |
| 43 | for (; times_restarted_ < kMaxTimesRestarted; times_restarted_++) { |
| 44 | // Start or restart symbolizer if we failed to send command to it. |
| 45 | if (const char *res = SendCommandImpl(command)) |
| 46 | return res; |
| 47 | Restart(); |
| 48 | } |
| 49 | if (!failed_to_start_) { |
| 50 | Report("WARNING: Failed to use and restart external symbolizer!\n"); |
| 51 | failed_to_start_ = true; |
| 52 | } |
| 53 | return 0; |
| 54 | } |
| 55 | |
| 56 | bool SymbolizerProcess::Restart() { |
| 57 | if (input_fd_ != kInvalidFd) |
| 58 | internal_close(input_fd_); |
| 59 | if (output_fd_ != kInvalidFd) |
| 60 | internal_close(output_fd_); |
| 61 | return StartSymbolizerSubprocess(); |
| 62 | } |
| 63 | |
| 64 | const char *SymbolizerProcess::SendCommandImpl(const char *command) { |
| 65 | if (input_fd_ == kInvalidFd || output_fd_ == kInvalidFd) |
| 66 | return 0; |
| 67 | if (!WriteToSymbolizer(command, internal_strlen(command))) |
| 68 | return 0; |
| 69 | if (!ReadFromSymbolizer(buffer_, kBufferSize)) |
| 70 | return 0; |
| 71 | return buffer_; |
| 72 | } |
| 73 | |
| 74 | bool SymbolizerProcess::ReadFromSymbolizer(char *buffer, uptr max_length) { |
| 75 | if (max_length == 0) |
| 76 | return true; |
| 77 | uptr read_len = 0; |
| 78 | while (true) { |
| 79 | uptr just_read = internal_read(input_fd_, buffer + read_len, |
| 80 | max_length - read_len - 1); |
| 81 | // We can't read 0 bytes, as we don't expect external symbolizer to close |
| 82 | // its stdout. |
| 83 | if (just_read == 0 || just_read == (uptr)-1) { |
| 84 | Report("WARNING: Can't read from symbolizer at fd %d\n", input_fd_); |
| 85 | return false; |
| 86 | } |
| 87 | read_len += just_read; |
| 88 | if (ReachedEndOfOutput(buffer, read_len)) |
| 89 | break; |
| 90 | } |
| 91 | buffer[read_len] = '\0'; |
| 92 | return true; |
| 93 | } |
| 94 | |
| 95 | bool SymbolizerProcess::WriteToSymbolizer(const char *buffer, uptr length) { |
| 96 | if (length == 0) |
| 97 | return true; |
| 98 | uptr write_len = internal_write(output_fd_, buffer, length); |
| 99 | if (write_len == 0 || write_len == (uptr)-1) { |
| 100 | Report("WARNING: Can't write to symbolizer at fd %d\n", output_fd_); |
| 101 | return false; |
| 102 | } |
| 103 | return true; |
| 104 | } |
| 105 | |
| 106 | bool SymbolizerProcess::StartSymbolizerSubprocess() { |
| 107 | if (!FileExists(path_)) { |
| 108 | if (!reported_invalid_path_) { |
| 109 | Report("WARNING: invalid path to external symbolizer!\n"); |
| 110 | reported_invalid_path_ = true; |
| 111 | } |
| 112 | return false; |
| 113 | } |
| 114 | |
| 115 | int pid; |
| 116 | if (use_forkpty_) { |
| 117 | #if SANITIZER_MAC |
| 118 | fd_t fd = kInvalidFd; |
| 119 | // Use forkpty to disable buffering in the new terminal. |
| 120 | pid = forkpty(&fd, 0, 0, 0); |
| 121 | if (pid == -1) { |
| 122 | // forkpty() failed. |
| 123 | Report("WARNING: failed to fork external symbolizer (errno: %d)\n", |
| 124 | errno); |
| 125 | return false; |
| 126 | } else if (pid == 0) { |
| 127 | // Child subprocess. |
| 128 | ExecuteWithDefaultArgs(path_); |
| 129 | internal__exit(1); |
| 130 | } |
| 131 | |
| 132 | // Continue execution in parent process. |
| 133 | input_fd_ = output_fd_ = fd; |
| 134 | |
| 135 | // Disable echo in the new terminal, disable CR. |
| 136 | struct termios termflags; |
| 137 | tcgetattr(fd, &termflags); |
| 138 | termflags.c_oflag &= ~ONLCR; |
| 139 | termflags.c_lflag &= ~ECHO; |
| 140 | tcsetattr(fd, TCSANOW, &termflags); |
| 141 | #else // SANITIZER_MAC |
| 142 | UNIMPLEMENTED(); |
| 143 | #endif // SANITIZER_MAC |
| 144 | } else { |
| 145 | int *infd = NULL; |
| 146 | int *outfd = NULL; |
| 147 | // The client program may close its stdin and/or stdout and/or stderr |
| 148 | // thus allowing socketpair to reuse file descriptors 0, 1 or 2. |
| 149 | // In this case the communication between the forked processes may be |
| 150 | // broken if either the parent or the child tries to close or duplicate |
| 151 | // these descriptors. The loop below produces two pairs of file |
| 152 | // descriptors, each greater than 2 (stderr). |
| 153 | int sock_pair[5][2]; |
| 154 | for (int i = 0; i < 5; i++) { |
| 155 | if (pipe(sock_pair[i]) == -1) { |
| 156 | for (int j = 0; j < i; j++) { |
| 157 | internal_close(sock_pair[j][0]); |
| 158 | internal_close(sock_pair[j][1]); |
| 159 | } |
| 160 | Report("WARNING: Can't create a socket pair to start " |
| 161 | "external symbolizer (errno: %d)\n", errno); |
| 162 | return false; |
| 163 | } else if (sock_pair[i][0] > 2 && sock_pair[i][1] > 2) { |
| 164 | if (infd == NULL) { |
| 165 | infd = sock_pair[i]; |
| 166 | } else { |
| 167 | outfd = sock_pair[i]; |
| 168 | for (int j = 0; j < i; j++) { |
| 169 | if (sock_pair[j] == infd) continue; |
| 170 | internal_close(sock_pair[j][0]); |
| 171 | internal_close(sock_pair[j][1]); |
| 172 | } |
| 173 | break; |
| 174 | } |
| 175 | } |
| 176 | } |
| 177 | CHECK(infd); |
| 178 | CHECK(outfd); |
| 179 | |
| 180 | // Real fork() may call user callbacks registered with pthread_atfork(). |
| 181 | pid = internal_fork(); |
| 182 | if (pid == -1) { |
| 183 | // Fork() failed. |
| 184 | internal_close(infd[0]); |
| 185 | internal_close(infd[1]); |
| 186 | internal_close(outfd[0]); |
| 187 | internal_close(outfd[1]); |
| 188 | Report("WARNING: failed to fork external symbolizer " |
| 189 | " (errno: %d)\n", errno); |
| 190 | return false; |
| 191 | } else if (pid == 0) { |
| 192 | // Child subprocess. |
| 193 | internal_close(STDOUT_FILENO); |
| 194 | internal_close(STDIN_FILENO); |
| 195 | internal_dup2(outfd[0], STDIN_FILENO); |
| 196 | internal_dup2(infd[1], STDOUT_FILENO); |
| 197 | internal_close(outfd[0]); |
| 198 | internal_close(outfd[1]); |
| 199 | internal_close(infd[0]); |
| 200 | internal_close(infd[1]); |
| 201 | for (int fd = sysconf(_SC_OPEN_MAX); fd > 2; fd--) |
| 202 | internal_close(fd); |
| 203 | ExecuteWithDefaultArgs(path_); |
| 204 | internal__exit(1); |
| 205 | } |
| 206 | |
| 207 | // Continue execution in parent process. |
| 208 | internal_close(outfd[0]); |
| 209 | internal_close(infd[1]); |
| 210 | input_fd_ = infd[0]; |
| 211 | output_fd_ = outfd[1]; |
| 212 | } |
| 213 | |
| 214 | // Check that symbolizer subprocess started successfully. |
| 215 | int pid_status; |
| 216 | SleepForMillis(kSymbolizerStartupTimeMillis); |
| 217 | int exited_pid = waitpid(pid, &pid_status, WNOHANG); |
| 218 | if (exited_pid != 0) { |
| 219 | // Either waitpid failed, or child has already exited. |
| 220 | Report("WARNING: external symbolizer didn't start up correctly!\n"); |
| 221 | return false; |
| 222 | } |
| 223 | |
| 224 | return true; |
| 225 | } |
| 226 | |
| 227 | } // namespace __sanitizer |
| 228 | |
| 229 | #endif // SANITIZER_POSIX |