diff options
Diffstat (limited to 'executor/subprocess.h')
| -rw-r--r-- | executor/subprocess.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/executor/subprocess.h b/executor/subprocess.h index 4477cc482..2553422a9 100644 --- a/executor/subprocess.h +++ b/executor/subprocess.h @@ -17,9 +17,17 @@ public: if (posix_spawn_file_actions_init(&actions)) fail("posix_spawn_file_actions_init failed"); int max_fd = 0; - for (auto pair : fds) { + for (auto pair : fds) max_fd = std::max(max_fd, pair.second); + for (auto pair : fds) { if (pair.first != -1) { + // Remapping won't work if fd's overlap with the target range: + // we can dup something onto fd we need to dup later, in such case the later fd + // will be wrong. Resolving this would require some tricky multi-pass remapping. + // So we just require the caller to not do that. + if (pair.first <= max_fd) + failmsg("bad subprocess fd", "%d->%d max_fd=%d", + pair.first, pair.second, max_fd); if (posix_spawn_file_actions_adddup2(&actions, pair.first, pair.second)) fail("posix_spawn_file_actions_adddup2 failed"); } else { |