blob: c55b09026e5465d6d7861415eb579d5aa6e483bf [file] [log] [blame]
// Copyright (c) 2011 The Chromium OS 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 <map>
#include <string>
#include <tr1/memory>
#include <vector>
#include <glib.h>
#include "base/basictypes.h"
#include "base/logging.h"
// The Subprocess class is a singleton. It's used to spawn off a subprocess
// and get notified when the subprocess exits. The result of Exec() can
// be saved and used to cancel the callback request. If you know you won't
// call CancelExec(), you may safely lose the return value from Exec().
namespace chromeos_update_engine {
class Subprocess {
typedef void(*ExecCallback)(int return_code,
const std::string& output,
void *p);
static void Init() {
subprocess_singleton_ = new Subprocess;
// Returns a tag > 0 on success.
uint32_t Exec(const std::vector<std::string>& cmd,
ExecCallback callback,
void* p);
// Used to cancel the callback. The process will still run to completion.
void CancelExec(uint32_t tag);
// Executes a command synchronously. Returns true on success. If |stdout| is
// non-null, the process output is stored in it, otherwise the output is
// logged. Note that stderr is redirected to stdout.
static bool SynchronousExecFlags(const std::vector<std::string>& cmd,
GSpawnFlags flags,
int* return_code,
std::string* stdout);
static bool SynchronousExec(const std::vector<std::string>& cmd,
int* return_code,
std::string* stdout);
// Gets the one instance
static Subprocess& Get() {
return *subprocess_singleton_;
// Returns true iff there is at least one subprocess we're waiting on.
bool SubprocessInFlight();
struct SubprocessRecord {
: tag(0),
gioout_tag(0) {}
uint32_t tag;
ExecCallback callback;
void* callback_data;
GIOChannel* gioout;
guint gioout_tag;
std::string stdout;
Subprocess() {}
// Callback for when any subprocess terminates. This calls the user
// requested callback.
static void GChildExitedCallback(GPid pid, gint status, gpointer data);
// Callback which runs in the child before exec to redirect stderr onto
// stdout.
static void GRedirectStderrToStdout(gpointer user_data);
// Callback which runs whenever there is input available on the subprocess
// stdout pipe.
static gboolean GStdoutWatchCallback(GIOChannel* source,
GIOCondition condition,
gpointer data);
// The global instance.
static Subprocess* subprocess_singleton_;
// A map from the asynchronous subprocess tag (see Exec) to the subprocess
// record structure for all active asynchronous subprocesses.
std::map<int, std::tr1::shared_ptr<SubprocessRecord> > subprocess_records_;
} // namespace chromeos_update_engine