| 82 | |
| 83 | |
| 84 | class GdbSession: |
| 85 | proc = None |
| 86 | verbose = True |
| 87 | |
| 88 | def __init__(self, *args, **env): |
| 89 | # Let stderr through to let pytest display it separately on errors |
| 90 | gdb_env = environment_for_gdb() |
| 91 | gdb_env.update(env) |
| 92 | self.proc = subprocess.Popen(gdb_command + list(args), |
| 93 | env=gdb_env, bufsize=0, |
| 94 | stdin=subprocess.PIPE, |
| 95 | stdout=subprocess.PIPE) |
| 96 | self.last_stdout = [] |
| 97 | self.last_stdout_line = b"" |
| 98 | |
| 99 | def wait_until_ready(self): |
| 100 | """ |
| 101 | Record output until the gdb prompt displays. Return recorded output. |
| 102 | """ |
| 103 | # TODO: add timeout? |
| 104 | while (not self.last_stdout_line.startswith(b"(gdb) ") and |
| 105 | self.proc.poll() is None): |
| 106 | block = self.proc.stdout.read(4096) |
| 107 | if self.verbose: |
| 108 | sys.stdout.buffer.write(block) |
| 109 | sys.stdout.buffer.flush() |
| 110 | block, sep, last_line = block.rpartition(b"\n") |
| 111 | if sep: |
| 112 | self.last_stdout.append(self.last_stdout_line) |
| 113 | self.last_stdout.append(block + sep) |
| 114 | self.last_stdout_line = last_line |
| 115 | else: |
| 116 | assert block == b"" |
| 117 | self.last_stdout_line += last_line |
| 118 | |
| 119 | if self.proc.poll() is not None: |
| 120 | raise IOError("gdb session terminated unexpectedly") |
| 121 | |
| 122 | out = b"".join(self.last_stdout).decode('utf-8') |
| 123 | self.last_stdout = [] |
| 124 | self.last_stdout_line = b"" |
| 125 | return out |
| 126 | |
| 127 | def issue_command(self, line): |
| 128 | line = line.encode('utf-8') + b"\n" |
| 129 | if self.verbose: |
| 130 | sys.stdout.buffer.write(line) |
| 131 | sys.stdout.buffer.flush() |
| 132 | self.proc.stdin.write(line) |
| 133 | self.proc.stdin.flush() |
| 134 | |
| 135 | def run_command(self, line): |
| 136 | self.issue_command(line) |
| 137 | return self.wait_until_ready() |
| 138 | |
| 139 | def print_value(self, expr): |
| 140 | """ |
| 141 | Ask gdb to print the value of an expression and return the result. |