diff options
Diffstat (limited to 'sandbox/linux/services/init_process_reaper.cc')
-rw-r--r-- | sandbox/linux/services/init_process_reaper.cc | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/sandbox/linux/services/init_process_reaper.cc b/sandbox/linux/services/init_process_reaper.cc new file mode 100644 index 0000000000..2e0b90b7b5 --- /dev/null +++ b/sandbox/linux/services/init_process_reaper.cc @@ -0,0 +1,101 @@ +// Copyright 2013 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +#include "sandbox/linux/services/init_process_reaper.h" + +#include <signal.h> +#include <string.h> +#include <sys/socket.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <unistd.h> + +#include "base/callback.h" +#include "base/logging.h" +#include "base/posix/eintr_wrapper.h" + +namespace sandbox { + +namespace { + +void DoNothingSignalHandler(int signal) {} + +} // namespace + +bool CreateInitProcessReaper(base::Closure* post_fork_parent_callback) { + int sync_fds[2]; + // We want to use send, so we can't use a pipe + if (socketpair(AF_UNIX, SOCK_STREAM, 0, sync_fds)) { + PLOG(ERROR) << "Failed to create socketpair"; + return false; + } + pid_t child_pid = fork(); + if (child_pid == -1) { + int close_ret; + close_ret = IGNORE_EINTR(close(sync_fds[0])); + DPCHECK(!close_ret); + close_ret = IGNORE_EINTR(close(sync_fds[1])); + DPCHECK(!close_ret); + return false; + } + if (child_pid) { + // In the parent, assuming the role of an init process. + // The disposition for SIGCHLD cannot be SIG_IGN or wait() will only return + // once all of our childs are dead. Since we're init we need to reap childs + // as they come. + struct sigaction action; + memset(&action, 0, sizeof(action)); + action.sa_handler = &DoNothingSignalHandler; + CHECK(sigaction(SIGCHLD, &action, NULL) == 0); + + int close_ret; + close_ret = IGNORE_EINTR(close(sync_fds[0])); + DPCHECK(!close_ret); + close_ret = shutdown(sync_fds[1], SHUT_RD); + DPCHECK(!close_ret); + if (post_fork_parent_callback) + post_fork_parent_callback->Run(); + // Tell the child to continue + CHECK(HANDLE_EINTR(send(sync_fds[1], "C", 1, MSG_NOSIGNAL)) == 1); + close_ret = IGNORE_EINTR(close(sync_fds[1])); + DPCHECK(!close_ret); + + for (;;) { + // Loop until we have reaped our one natural child + siginfo_t reaped_child_info; + int wait_ret = + HANDLE_EINTR(waitid(P_ALL, 0, &reaped_child_info, WEXITED)); + if (wait_ret) + _exit(1); + if (reaped_child_info.si_pid == child_pid) { + int exit_code = 0; + // We're done waiting + if (reaped_child_info.si_code == CLD_EXITED) { + exit_code = reaped_child_info.si_status; + } + // Exit with the same exit code as our parent. Exit with 0 if we got + // signaled. + _exit(exit_code); + } + } + } else { + // The child needs to wait for the parent to run the callback to avoid a + // race condition. + int close_ret; + close_ret = IGNORE_EINTR(close(sync_fds[1])); + DPCHECK(!close_ret); + close_ret = shutdown(sync_fds[0], SHUT_WR); + DPCHECK(!close_ret); + char should_continue; + int read_ret = HANDLE_EINTR(read(sync_fds[0], &should_continue, 1)); + close_ret = IGNORE_EINTR(close(sync_fds[0])); + DPCHECK(!close_ret); + if (read_ret == 1) + return true; + else + return false; + } +} + +} // namespace sandbox. |