michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "Hal.h"
michael@0: #include <sys/syscall.h>
michael@0: #include <sys/vfs.h>
michael@0: #include <fcntl.h>
michael@0: #include <errno.h>
michael@0: #include "nsIObserverService.h"
michael@0: #include "nsIDiskSpaceWatcher.h"
michael@0: #include "mozilla/ModuleUtils.h"
michael@0: #include "nsAutoPtr.h"
michael@0: #include "nsThreadUtils.h"
michael@0: #include "base/message_loop.h"
michael@0: #include "mozilla/Preferences.h"
michael@0: #include "mozilla/Services.h"
michael@0: #include "nsXULAppAPI.h"
michael@0: #include "fanotify.h"
michael@0: #include "DiskSpaceWatcher.h"
michael@0: 
michael@0: using namespace mozilla;
michael@0: 
michael@0: namespace mozilla { namespace hal_impl { class GonkDiskSpaceWatcher; } }
michael@0: 
michael@0: using namespace mozilla::hal_impl;
michael@0: 
michael@0: template<>
michael@0: struct RunnableMethodTraits<GonkDiskSpaceWatcher>
michael@0: {
michael@0:   static void RetainCallee(GonkDiskSpaceWatcher* obj) { }
michael@0:   static void ReleaseCallee(GonkDiskSpaceWatcher* obj) { }
michael@0: };
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace hal_impl {
michael@0: 
michael@0: // fanotify_init and fanotify_mark functions are syscalls.
michael@0: // The user space bits are not part of bionic so we add them here
michael@0: // as well as fanotify.h
michael@0: int fanotify_init (unsigned int flags, unsigned int event_f_flags)
michael@0: {
michael@0:   return syscall(367, flags, event_f_flags);
michael@0: }
michael@0: 
michael@0: // Add, remove, or modify an fanotify mark on a filesystem object.
michael@0: int fanotify_mark (int fanotify_fd, unsigned int flags,
michael@0:                    uint64_t mask, int dfd, const char *pathname)
michael@0: {
michael@0: 
michael@0:   // On 32 bits platforms we have to convert the 64 bits mask into
michael@0:   // two 32 bits ints.
michael@0:   if (sizeof(void *) == 4) {
michael@0:     union {
michael@0:       uint64_t _64;
michael@0:       uint32_t _32[2];
michael@0:     } _mask;
michael@0:     _mask._64 = mask;
michael@0:     return syscall(368, fanotify_fd, flags, _mask._32[0], _mask._32[1],
michael@0:                    dfd, pathname);
michael@0:   }
michael@0: 
michael@0:   return syscall(368, fanotify_fd, flags, mask, dfd, pathname);
michael@0: }
michael@0: 
michael@0: class GonkDiskSpaceWatcher MOZ_FINAL : public MessageLoopForIO::Watcher
michael@0: {
michael@0: public:
michael@0:   GonkDiskSpaceWatcher();
michael@0:   ~GonkDiskSpaceWatcher() {};
michael@0: 
michael@0:   virtual void OnFileCanReadWithoutBlocking(int aFd);
michael@0: 
michael@0:   // We should never write to the fanotify fd.
michael@0:   virtual void OnFileCanWriteWithoutBlocking(int aFd)
michael@0:   {
michael@0:     MOZ_CRASH("Must not write to fanotify fd");
michael@0:   }
michael@0: 
michael@0:   void DoStart();
michael@0:   void DoStop();
michael@0: 
michael@0: private:
michael@0:   void NotifyUpdate();
michael@0: 
michael@0:   uint64_t mLowThreshold;
michael@0:   uint64_t mHighThreshold;
michael@0:   TimeDuration mTimeout;
michael@0:   TimeStamp  mLastTimestamp;
michael@0:   uint64_t mLastFreeSpace;
michael@0:   uint32_t mSizeDelta;
michael@0: 
michael@0:   bool mIsDiskFull;
michael@0:   uint64_t mFreeSpace;
michael@0: 
michael@0:   int mFd;
michael@0:   MessageLoopForIO::FileDescriptorWatcher mReadWatcher;
michael@0: };
michael@0: 
michael@0: static GonkDiskSpaceWatcher* gHalDiskSpaceWatcher = nullptr;
michael@0: 
michael@0: #define WATCHER_PREF_LOW        "disk_space_watcher.low_threshold"
michael@0: #define WATCHER_PREF_HIGH       "disk_space_watcher.high_threshold"
michael@0: #define WATCHER_PREF_TIMEOUT    "disk_space_watcher.timeout"
michael@0: #define WATCHER_PREF_SIZE_DELTA "disk_space_watcher.size_delta"
michael@0: 
michael@0: static const char kWatchedPath[] = "/data";
michael@0: 
michael@0: // Helper class to dispatch calls to xpcom on the main thread.
michael@0: class DiskSpaceNotifier : public nsRunnable
michael@0: {
michael@0: public:
michael@0:   DiskSpaceNotifier(const bool aIsDiskFull, const uint64_t aFreeSpace) :
michael@0:     mIsDiskFull(aIsDiskFull),
michael@0:     mFreeSpace(aFreeSpace) {}
michael@0: 
michael@0:   NS_IMETHOD Run()
michael@0:   {
michael@0:     MOZ_ASSERT(NS_IsMainThread());
michael@0:     DiskSpaceWatcher::UpdateState(mIsDiskFull, mFreeSpace);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   bool mIsDiskFull;
michael@0:   uint64_t mFreeSpace;
michael@0: };
michael@0: 
michael@0: // Helper runnable to delete the watcher on the main thread.
michael@0: class DiskSpaceCleaner : public nsRunnable
michael@0: {
michael@0: public:
michael@0:   NS_IMETHOD Run()
michael@0:   {
michael@0:     MOZ_ASSERT(NS_IsMainThread());
michael@0:     if (gHalDiskSpaceWatcher) {
michael@0:       delete gHalDiskSpaceWatcher;
michael@0:       gHalDiskSpaceWatcher = nullptr;
michael@0:     }
michael@0:     return NS_OK;
michael@0:   }
michael@0: };
michael@0: 
michael@0: GonkDiskSpaceWatcher::GonkDiskSpaceWatcher() :
michael@0:   mLastFreeSpace(UINT64_MAX),
michael@0:   mIsDiskFull(false),
michael@0:   mFreeSpace(UINT64_MAX),
michael@0:   mFd(-1)
michael@0: {
michael@0:   MOZ_ASSERT(NS_IsMainThread());
michael@0:   MOZ_ASSERT(gHalDiskSpaceWatcher == nullptr);
michael@0: 
michael@0:   // Default values: 5MB for low threshold, 10MB for high threshold, and
michael@0:   // a timeout of 5 seconds.
michael@0:   mLowThreshold = Preferences::GetInt(WATCHER_PREF_LOW, 5) * 1024 * 1024;
michael@0:   mHighThreshold = Preferences::GetInt(WATCHER_PREF_HIGH, 10) * 1024 * 1024;
michael@0:   mTimeout = TimeDuration::FromSeconds(Preferences::GetInt(WATCHER_PREF_TIMEOUT, 5));
michael@0:   mSizeDelta = Preferences::GetInt(WATCHER_PREF_SIZE_DELTA, 1) * 1024 * 1024;
michael@0: }
michael@0: 
michael@0: void
michael@0: GonkDiskSpaceWatcher::DoStart()
michael@0: {
michael@0:   NS_ASSERTION(XRE_GetIOMessageLoop() == MessageLoopForIO::current(),
michael@0:                "Not on the correct message loop");
michael@0: 
michael@0:   mFd = fanotify_init(FAN_CLASS_NOTIF, FAN_CLOEXEC);
michael@0:   if (mFd == -1) {
michael@0:     NS_WARNING("Error calling inotify_init()");
michael@0:     if (errno == ENOSYS) {
michael@0:       printf_stderr("Warning: No fanotify support in this device's kernel.\n");
michael@0:     }
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   if (fanotify_mark(mFd, FAN_MARK_ADD | FAN_MARK_MOUNT, FAN_CLOSE,
michael@0:                     0, kWatchedPath) < 0) {
michael@0:     NS_WARNING("Error calling fanotify_mark");
michael@0:     close(mFd);
michael@0:     mFd = -1;
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   if (!MessageLoopForIO::current()->WatchFileDescriptor(
michael@0:     mFd, /* persistent = */ true,
michael@0:     MessageLoopForIO::WATCH_READ,
michael@0:     &mReadWatcher, gHalDiskSpaceWatcher)) {
michael@0:       NS_WARNING("Unable to watch fanotify fd.");
michael@0:       close(mFd);
michael@0:       mFd = -1;
michael@0:   }
michael@0: }
michael@0: 
michael@0: void
michael@0: GonkDiskSpaceWatcher::DoStop()
michael@0: {
michael@0:   NS_ASSERTION(XRE_GetIOMessageLoop() == MessageLoopForIO::current(),
michael@0:                "Not on the correct message loop");
michael@0: 
michael@0:   if (mFd != -1) {
michael@0:     mReadWatcher.StopWatchingFileDescriptor();
michael@0:     fanotify_mark(mFd, FAN_MARK_FLUSH, 0, 0, kWatchedPath);
michael@0:     close(mFd);
michael@0:     mFd = -1;
michael@0:   }
michael@0: 
michael@0:   // Dispatch the cleanup to the main thread.
michael@0:   nsCOMPtr<nsIRunnable> runnable = new DiskSpaceCleaner();
michael@0:   NS_DispatchToMainThread(runnable, NS_DISPATCH_NORMAL);
michael@0: }
michael@0: 
michael@0: // We are called off the main thread, so we proxy first to the main thread
michael@0: // before calling the xpcom object.
michael@0: void
michael@0: GonkDiskSpaceWatcher::NotifyUpdate()
michael@0: {
michael@0:   mLastTimestamp = TimeStamp::Now();
michael@0:   mLastFreeSpace = mFreeSpace;
michael@0: 
michael@0:   nsCOMPtr<nsIRunnable> runnable =
michael@0:     new DiskSpaceNotifier(mIsDiskFull, mFreeSpace);
michael@0:   NS_DispatchToMainThread(runnable, NS_DISPATCH_NORMAL);
michael@0: }
michael@0: 
michael@0: void
michael@0: GonkDiskSpaceWatcher::OnFileCanReadWithoutBlocking(int aFd)
michael@0: {
michael@0:   struct fanotify_event_metadata* fem = nullptr;
michael@0:   char buf[4096];
michael@0:   struct statfs sfs;
michael@0:   int32_t len, rc;
michael@0: 
michael@0:   do {
michael@0:     len = read(aFd, buf, sizeof(buf));
michael@0:   } while(len == -1 && errno == EINTR);
michael@0: 
michael@0:   // Bail out if the file is busy.
michael@0:   if (len < 0 && errno == ETXTBSY) {
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   // We should get an exact multiple of fanotify_event_metadata
michael@0:   if (len <= 0 || (len % FAN_EVENT_METADATA_LEN != 0)) {
michael@0:     printf_stderr("About to crash: fanotify_event_metadata read error.");
michael@0:     MOZ_CRASH();
michael@0:   }
michael@0: 
michael@0:   fem = reinterpret_cast<fanotify_event_metadata *>(buf);
michael@0: 
michael@0:   while (FAN_EVENT_OK(fem, len)) {
michael@0:     rc = fstatfs(fem->fd, &sfs);
michael@0:     if (rc < 0) {
michael@0:       NS_WARNING("Unable to stat fan_notify fd");
michael@0:     } else {
michael@0:       bool firstRun = mFreeSpace == UINT64_MAX;
michael@0:       mFreeSpace = sfs.f_bavail * sfs.f_bsize;
michael@0:       // We change from full <-> free depending on the free space and the
michael@0:       // low and high thresholds.
michael@0:       // Once we are in 'full' mode we send updates for all size changes with
michael@0:       // a minimum of time between messages or when we cross a size change
michael@0:       // threshold.
michael@0:       if (firstRun) {
michael@0:         mIsDiskFull = mFreeSpace <= mLowThreshold;
michael@0:         // Always notify the current state at first run.
michael@0:         NotifyUpdate();
michael@0:       } else if (!mIsDiskFull && (mFreeSpace <= mLowThreshold)) {
michael@0:         mIsDiskFull = true;
michael@0:         NotifyUpdate();
michael@0:       } else if (mIsDiskFull && (mFreeSpace > mHighThreshold)) {
michael@0:         mIsDiskFull = false;
michael@0:         NotifyUpdate();
michael@0:       } else if (mIsDiskFull) {
michael@0:         if (mTimeout < TimeStamp::Now() - mLastTimestamp ||
michael@0:             mSizeDelta < llabs(mFreeSpace - mLastFreeSpace)) {
michael@0:           NotifyUpdate();
michael@0:         }
michael@0:       }
michael@0:     }
michael@0:     close(fem->fd);
michael@0:     fem = FAN_EVENT_NEXT(fem, len);
michael@0:   }
michael@0: }
michael@0: 
michael@0: void
michael@0: StartDiskSpaceWatcher()
michael@0: {
michael@0:   MOZ_ASSERT(NS_IsMainThread());
michael@0: 
michael@0:   // Bail out if called several times.
michael@0:   if (gHalDiskSpaceWatcher != nullptr) {
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   gHalDiskSpaceWatcher = new GonkDiskSpaceWatcher();
michael@0: 
michael@0:   XRE_GetIOMessageLoop()->PostTask(
michael@0:     FROM_HERE,
michael@0:     NewRunnableMethod(gHalDiskSpaceWatcher, &GonkDiskSpaceWatcher::DoStart));
michael@0: }
michael@0: 
michael@0: void
michael@0: StopDiskSpaceWatcher()
michael@0: {
michael@0:   MOZ_ASSERT(NS_IsMainThread());
michael@0:   if (!gHalDiskSpaceWatcher) {
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   XRE_GetIOMessageLoop()->PostTask(
michael@0:     FROM_HERE,
michael@0:     NewRunnableMethod(gHalDiskSpaceWatcher, &GonkDiskSpaceWatcher::DoStop));
michael@0: }
michael@0: 
michael@0: } // namespace hal_impl
michael@0: } // namespace mozilla