diff options
Diffstat (limited to 'xpcom/build/NSPRInterposer.cpp')
| -rw-r--r-- | xpcom/build/NSPRInterposer.cpp | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/xpcom/build/NSPRInterposer.cpp b/xpcom/build/NSPRInterposer.cpp new file mode 100644 index 0000000000..184c3793e7 --- /dev/null +++ b/xpcom/build/NSPRInterposer.cpp @@ -0,0 +1,207 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "IOInterposer.h" +#include "NSPRInterposer.h" + +#include "prio.h" +#include "private/pprio.h" +#include "nsDebug.h" +#include "nscore.h" + +#include <sys/param.h> +#ifdef XP_MACOSX +# include <fcntl.h> +#else +# include "prprf.h" +# include <unistd.h> +#endif + +namespace { + +/* Original IO methods */ +PRCloseFN sCloseFn = nullptr; +PRReadFN sReadFn = nullptr; +PRWriteFN sWriteFn = nullptr; +PRFsyncFN sFSyncFn = nullptr; +PRFileInfoFN sFileInfoFn = nullptr; +PRFileInfo64FN sFileInfo64Fn = nullptr; + +static int32_t GetPathFromFd(int32_t aFd, char* aBuf, size_t aBufSize) { +#ifdef XP_MACOSX + NS_ASSERTION(aBufSize >= MAXPATHLEN, + "aBufSize should be a least MAXPATHLEN long"); + + return fcntl(aFd, F_GETPATH, aBuf); +#else + char procPath[32]; + if (PR_snprintf(procPath, sizeof(procPath), "/proc/self/fd/%i", aFd) == + (PRUint32)-1) { + return -1; + } + + int32_t ret = readlink(procPath, aBuf, aBufSize - 1); + if (ret > -1) { + aBuf[ret] = '\0'; + } + + return ret; +#endif +} + +/** + * RAII class for timing the duration of an NSPR I/O call and reporting the + * result to the mozilla::IOInterposeObserver API. + */ +class NSPRIOAutoObservation : public mozilla::IOInterposeObserver::Observation { + public: + explicit NSPRIOAutoObservation(mozilla::IOInterposeObserver::Operation aOp, + PRFileDesc* aFd) + : mozilla::IOInterposeObserver::Observation(aOp, "NSPRIOInterposer") { + char filename[MAXPATHLEN]; + if (mShouldReport && aFd && + GetPathFromFd(PR_FileDesc2NativeHandle(aFd), filename, + sizeof(filename)) != -1) { + CopyUTF8toUTF16(mozilla::MakeStringSpan(filename), mFilename); + } else { + mFilename.Truncate(); + } + } + + void Filename(nsAString& aFilename) override { aFilename = mFilename; } + + ~NSPRIOAutoObservation() override { Report(); } + + private: + nsString mFilename; +}; + +PRStatus PR_CALLBACK interposedClose(PRFileDesc* aFd) { + // If we don't have a valid original function pointer something is very wrong. + NS_ASSERTION(sCloseFn, "NSPR IO Interposing: sCloseFn is NULL"); + + NSPRIOAutoObservation timer(mozilla::IOInterposeObserver::OpClose, aFd); + return sCloseFn(aFd); +} + +int32_t PR_CALLBACK interposedRead(PRFileDesc* aFd, void* aBuf, int32_t aAmt) { + // If we don't have a valid original function pointer something is very wrong. + NS_ASSERTION(sReadFn, "NSPR IO Interposing: sReadFn is NULL"); + + NSPRIOAutoObservation timer(mozilla::IOInterposeObserver::OpRead, aFd); + return sReadFn(aFd, aBuf, aAmt); +} + +int32_t PR_CALLBACK interposedWrite(PRFileDesc* aFd, const void* aBuf, + int32_t aAmt) { + // If we don't have a valid original function pointer something is very wrong. + NS_ASSERTION(sWriteFn, "NSPR IO Interposing: sWriteFn is NULL"); + + NSPRIOAutoObservation timer(mozilla::IOInterposeObserver::OpWrite, aFd); + return sWriteFn(aFd, aBuf, aAmt); +} + +PRStatus PR_CALLBACK interposedFSync(PRFileDesc* aFd) { + // If we don't have a valid original function pointer something is very wrong. + NS_ASSERTION(sFSyncFn, "NSPR IO Interposing: sFSyncFn is NULL"); + + NSPRIOAutoObservation timer(mozilla::IOInterposeObserver::OpFSync, aFd); + return sFSyncFn(aFd); +} + +PRStatus PR_CALLBACK interposedFileInfo(PRFileDesc* aFd, PRFileInfo* aInfo) { + // If we don't have a valid original function pointer something is very wrong. + NS_ASSERTION(sFileInfoFn, "NSPR IO Interposing: sFileInfoFn is NULL"); + + NSPRIOAutoObservation timer(mozilla::IOInterposeObserver::OpStat, aFd); + return sFileInfoFn(aFd, aInfo); +} + +PRStatus PR_CALLBACK interposedFileInfo64(PRFileDesc* aFd, + PRFileInfo64* aInfo) { + // If we don't have a valid original function pointer something is very wrong. + NS_ASSERTION(sFileInfo64Fn, "NSPR IO Interposing: sFileInfo64Fn is NULL"); + + NSPRIOAutoObservation timer(mozilla::IOInterposeObserver::OpStat, aFd); + return sFileInfo64Fn(aFd, aInfo); +} + +} // namespace + +namespace mozilla { + +void InitNSPRIOInterposing() { + // Check that we have not interposed any of the IO methods before + MOZ_ASSERT(!sCloseFn && !sReadFn && !sWriteFn && !sFSyncFn && !sFileInfoFn && + !sFileInfo64Fn); + + // We can't actually use this assertion because we initialize this code + // before XPCOM is initialized, so NS_IsMainThread() always returns false. + // MOZ_ASSERT(NS_IsMainThread()); + + // Get IO methods from NSPR and const cast the structure so we can modify it. + PRIOMethods* methods = const_cast<PRIOMethods*>(PR_GetFileMethods()); + + // Something is badly wrong if we don't get IO methods... However, we don't + // want to crash over that in non-debug builds. This is unlikely to happen + // so an assert is enough, no need to report it to the caller. + MOZ_ASSERT(methods); + if (!methods) { + return; + } + + // Store original functions + sCloseFn = methods->close; + sReadFn = methods->read; + sWriteFn = methods->write; + sFSyncFn = methods->fsync; + sFileInfoFn = methods->fileInfo; + sFileInfo64Fn = methods->fileInfo64; + + // Overwrite with our interposed functions + methods->close = &interposedClose; + methods->read = &interposedRead; + methods->write = &interposedWrite; + methods->fsync = &interposedFSync; + methods->fileInfo = &interposedFileInfo; + methods->fileInfo64 = &interposedFileInfo64; +} + +void ClearNSPRIOInterposing() { + // If we have already cleared IO interposing, or not initialized it this is + // actually bad. + MOZ_ASSERT(sCloseFn && sReadFn && sWriteFn && sFSyncFn && sFileInfoFn && + sFileInfo64Fn); + + // Get IO methods from NSPR and const cast the structure so we can modify it. + PRIOMethods* methods = const_cast<PRIOMethods*>(PR_GetFileMethods()); + + // Something is badly wrong if we don't get IO methods... However, we don't + // want to crash over that in non-debug builds. This is unlikely to happen + // so an assert is enough, no need to report it to the caller. + MOZ_ASSERT(methods); + if (!methods) { + return; + } + + // Restore original functions + methods->close = sCloseFn; + methods->read = sReadFn; + methods->write = sWriteFn; + methods->fsync = sFSyncFn; + methods->fileInfo = sFileInfoFn; + methods->fileInfo64 = sFileInfo64Fn; + + // Forget about original functions + sCloseFn = nullptr; + sReadFn = nullptr; + sWriteFn = nullptr; + sFSyncFn = nullptr; + sFileInfoFn = nullptr; + sFileInfo64Fn = nullptr; +} + +} // namespace mozilla |