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
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "IOInterposer.h"
michael@0: #include "NSPRInterposer.h"
michael@0: 
michael@0: #include "prio.h"
michael@0: #include "private/pprio.h"
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: using namespace mozilla;
michael@0: 
michael@0: /* Original IO methods */
michael@0: PRCloseFN sCloseFn = nullptr;
michael@0: PRReadFN  sReadFn  = nullptr;
michael@0: PRWriteFN sWriteFn = nullptr;
michael@0: PRFsyncFN sFSyncFn = nullptr;
michael@0: PRFileInfoFN sFileInfoFn = nullptr;
michael@0: PRFileInfo64FN sFileInfo64Fn = nullptr;
michael@0: 
michael@0: /**
michael@0:  * RAII class for timing the duration of an NSPR I/O call and reporting the
michael@0:  * result to the IOInterposeObserver API.
michael@0:  */
michael@0: class NSPRIOAutoObservation : public IOInterposeObserver::Observation
michael@0: {
michael@0: public:
michael@0:   NSPRIOAutoObservation(IOInterposeObserver::Operation aOp)
michael@0:     : IOInterposeObserver::Observation(aOp, "NSPRIOInterposer")
michael@0:   {
michael@0:   }
michael@0: 
michael@0:   ~NSPRIOAutoObservation()
michael@0:   {
michael@0:     Report();
michael@0:   }
michael@0: };
michael@0: 
michael@0: PRStatus PR_CALLBACK interposedClose(PRFileDesc* aFd)
michael@0: {
michael@0:   // If we don't have a valid original function pointer something is very wrong.
michael@0:   NS_ASSERTION(sCloseFn, "NSPR IO Interposing: sCloseFn is NULL");
michael@0: 
michael@0:   NSPRIOAutoObservation timer(IOInterposeObserver::OpClose);
michael@0:   return sCloseFn(aFd);
michael@0: }
michael@0: 
michael@0: int32_t PR_CALLBACK interposedRead(PRFileDesc* aFd, void* aBuf, int32_t aAmt)
michael@0: {
michael@0:   // If we don't have a valid original function pointer something is very wrong.
michael@0:   NS_ASSERTION(sReadFn, "NSPR IO Interposing: sReadFn is NULL");
michael@0: 
michael@0:   NSPRIOAutoObservation timer(IOInterposeObserver::OpRead);
michael@0:   return sReadFn(aFd, aBuf, aAmt);
michael@0: }
michael@0: 
michael@0: int32_t PR_CALLBACK interposedWrite(PRFileDesc* aFd, const void* aBuf,
michael@0:                                     int32_t aAmt)
michael@0: {
michael@0:   // If we don't have a valid original function pointer something is very wrong.
michael@0:   NS_ASSERTION(sWriteFn, "NSPR IO Interposing: sWriteFn is NULL");
michael@0: 
michael@0:   NSPRIOAutoObservation timer(IOInterposeObserver::OpWrite);
michael@0:   return sWriteFn(aFd, aBuf, aAmt);
michael@0: }
michael@0: 
michael@0: PRStatus PR_CALLBACK interposedFSync(PRFileDesc* aFd)
michael@0: {
michael@0:   // If we don't have a valid original function pointer something is very wrong.
michael@0:   NS_ASSERTION(sFSyncFn, "NSPR IO Interposing: sFSyncFn is NULL");
michael@0: 
michael@0:   NSPRIOAutoObservation timer(IOInterposeObserver::OpFSync);
michael@0:   return sFSyncFn(aFd);
michael@0: }
michael@0: 
michael@0: PRStatus PR_CALLBACK interposedFileInfo(PRFileDesc *aFd, PRFileInfo *aInfo)
michael@0: {
michael@0:   // If we don't have a valid original function pointer something is very wrong.
michael@0:   NS_ASSERTION(sFileInfoFn, "NSPR IO Interposing: sFileInfoFn is NULL");
michael@0: 
michael@0:   NSPRIOAutoObservation timer(IOInterposeObserver::OpStat);
michael@0:   return sFileInfoFn(aFd, aInfo);
michael@0: }
michael@0: 
michael@0: PRStatus PR_CALLBACK interposedFileInfo64(PRFileDesc *aFd, PRFileInfo64 *aInfo)
michael@0: {
michael@0:   // If we don't have a valid original function pointer something is very wrong.
michael@0:   NS_ASSERTION(sFileInfo64Fn, "NSPR IO Interposing: sFileInfo64Fn is NULL");
michael@0: 
michael@0:   NSPRIOAutoObservation timer(IOInterposeObserver::OpStat);
michael@0:   return sFileInfo64Fn(aFd, aInfo);
michael@0: }
michael@0: 
michael@0: } // anonymous namespace
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: void InitNSPRIOInterposing()
michael@0: {
michael@0:   // Check that we have not interposed any of the IO methods before
michael@0:   MOZ_ASSERT(!sCloseFn && !sReadFn && !sWriteFn && !sFSyncFn && !sFileInfoFn &&
michael@0:              !sFileInfo64Fn);
michael@0: 
michael@0:   // We can't actually use this assertion because we initialize this code
michael@0:   // before XPCOM is initialized, so NS_IsMainThread() always returns false.
michael@0:   // MOZ_ASSERT(NS_IsMainThread());
michael@0: 
michael@0:   // Get IO methods from NSPR and const cast the structure so we can modify it.
michael@0:   PRIOMethods* methods = const_cast<PRIOMethods*>(PR_GetFileMethods());
michael@0: 
michael@0:   // Something is badly wrong if we don't get IO methods... However, we don't
michael@0:   // want to crash over that in non-debug builds. This is unlikely to happen
michael@0:   // so an assert is enough, no need to report it to the caller.
michael@0:   MOZ_ASSERT(methods);
michael@0:   if (!methods) {
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   // Store original functions
michael@0:   sCloseFn      = methods->close;
michael@0:   sReadFn       = methods->read;
michael@0:   sWriteFn      = methods->write;
michael@0:   sFSyncFn      = methods->fsync;
michael@0:   sFileInfoFn   = methods->fileInfo;
michael@0:   sFileInfo64Fn = methods->fileInfo64;
michael@0: 
michael@0:   // Overwrite with our interposed functions
michael@0:   methods->close      = &interposedClose;
michael@0:   methods->read       = &interposedRead;
michael@0:   methods->write      = &interposedWrite;
michael@0:   methods->fsync      = &interposedFSync;
michael@0:   methods->fileInfo   = &interposedFileInfo;
michael@0:   methods->fileInfo64 = &interposedFileInfo64;
michael@0: }
michael@0: 
michael@0: void ClearNSPRIOInterposing()
michael@0: {
michael@0:   // If we have already cleared IO interposing, or not initialized it this is
michael@0:   // actually bad.
michael@0:   MOZ_ASSERT(sCloseFn && sReadFn && sWriteFn && sFSyncFn && sFileInfoFn &&
michael@0:              sFileInfo64Fn);
michael@0: 
michael@0:   // Get IO methods from NSPR and const cast the structure so we can modify it.
michael@0:   PRIOMethods* methods = const_cast<PRIOMethods*>(PR_GetFileMethods());
michael@0: 
michael@0:   // Something is badly wrong if we don't get IO methods... However, we don't
michael@0:   // want to crash over that in non-debug builds. This is unlikely to happen
michael@0:   // so an assert is enough, no need to report it to the caller.
michael@0:   MOZ_ASSERT(methods);
michael@0:   if (!methods) {
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   // Restore original functions
michael@0:   methods->close      = sCloseFn;
michael@0:   methods->read       = sReadFn;
michael@0:   methods->write      = sWriteFn;
michael@0:   methods->fsync      = sFSyncFn;
michael@0:   methods->fileInfo   = sFileInfoFn;
michael@0:   methods->fileInfo64 = sFileInfo64Fn;
michael@0: 
michael@0:   // Forget about original functions
michael@0:   sCloseFn      = nullptr;
michael@0:   sReadFn       = nullptr;
michael@0:   sWriteFn      = nullptr;
michael@0:   sFSyncFn      = nullptr;
michael@0:   sFileInfoFn   = nullptr;
michael@0:   sFileInfo64Fn = nullptr;
michael@0: }
michael@0: 
michael@0: } // namespace mozilla
michael@0: