From ec2bd40d3e318baf6f22ee7a7ccbc57cb071af40 Mon Sep 17 00:00:00 2001
From: Nat Goodspeed <nat@lindenlab.com>
Date: Thu, 31 Oct 2019 12:39:31 -0400
Subject: [PATCH] DRTVWR-476: Encapsulate dup()/dup2() fd saving as
LLTempRedirect.
---
indra/llcommon/CMakeLists.txt | 2 +
indra/llcommon/llerror.cpp | 48 +++--------
indra/llcommon/lltempredirect.cpp | 138 ++++++++++++++++++++++++++++++
indra/llcommon/lltempredirect.h | 91 ++++++++++++++++++++
4 files changed, 241 insertions(+), 38 deletions(-)
create mode 100644 indra/llcommon/lltempredirect.cpp
create mode 100644 indra/llcommon/lltempredirect.h
diff --git a/indra/llcommon/CMakeLists.txt b/indra/llcommon/CMakeLists.txt
index 035b379246a..d17ee4c70a1 100644
--- a/indra/llcommon/CMakeLists.txt
+++ b/indra/llcommon/CMakeLists.txt
@@ -104,6 +104,7 @@ set(llcommon_SOURCE_FILES
llstring.cpp
llstringtable.cpp
llsys.cpp
+ lltempredirect.cpp
llthread.cpp
llthreadlocalstorage.cpp
llthreadsafequeue.cpp
@@ -228,6 +229,7 @@ set(llcommon_HEADER_FILES
llstaticstringtable.h
llstatsaccumulator.h
llsys.h
+ lltempredirect.h
llthread.h
llthreadlocalstorage.h
llthreadsafequeue.h
diff --git a/indra/llcommon/llerror.cpp b/indra/llcommon/llerror.cpp
index 457965b1fd0..2ae2cb6cbcf 100644
--- a/indra/llcommon/llerror.cpp
+++ b/indra/llcommon/llerror.cpp
@@ -39,8 +39,6 @@
#if !LL_WINDOWS
# include <syslog.h>
# include <unistd.h>
-#else
-# include <io.h>
#endif // !LL_WINDOWS
#include <vector>
#include "string.h"
@@ -54,20 +52,7 @@
#include "llsingleton.h"
#include "llstl.h"
#include "lltimer.h"
-
-#if LL_WINDOWS
-#define fhclose _close
-#define fhdup _dup
-#define fhdup2 _dup2
-#define fhfdopen _fdopen
-#define fhfileno _fileno
-#else
-#define fhclose ::close
-#define fhdup ::dup
-#define fhdup2 ::dup2
-#define fhfdopen ::fdopen
-#define fhfileno ::fileno
-#endif
+#include "lltempredirect.h"
namespace LLError
{
@@ -80,7 +65,6 @@ namespace LLError
LLSINGLETON(Settings);
public:
SettingsConfigPtr getSettingsConfig();
- ~Settings();
void reset();
SettingsStoragePtr saveAndReset();
@@ -90,7 +74,7 @@ namespace LLError
private:
SettingsConfigPtr mSettingsConfig;
- int mDupStderr;
+ LLTempRedirect mRedirect;
};
} // namespace LLError
@@ -162,8 +146,7 @@ namespace {
public:
RecordToFile(const std::string& filename):
mName(filename),
- mFile(LLFile::fopen(filename, "a")),
- mSavedStderr(LLError::Settings::instance().getDupStderr())
+ mFile(LLFile::fopen(filename, "a"))
{
if (!mFile)
{
@@ -174,16 +157,13 @@ namespace {
// We use a number of classic-C libraries, some of which write
// log output to stderr. The trouble with that is that unless
// you launch the viewer from a console, stderr output is
- // lost. Redirect STDERR_FILENO to write into this log file.
- fhdup2(fhfileno(mFile), fhfileno(stderr));
+ // lost. Redirect stderr to write into this log file.
+ mRedirect = LLTempRedirect(mFile, stderr);
}
}
~RecordToFile()
{
- // restore stderr to its original fileno so any subsequent output
- // to stderr goes to original stream
- fhdup2(mSavedStderr, fhfileno(stderr));
mFile.close();
}
@@ -214,7 +194,7 @@ namespace {
private:
const std::string mName;
LLUniqueFile mFile;
- int mSavedStderr;
+ LLTempRedirect mRedirect;
};
@@ -225,7 +205,7 @@ namespace {
mUseANSI(checkANSI()),
// use duplicate stderr file handle so THIS output isn't affected
// by our internal redirection of all (other) stderr output
- mStderr(fhfdopen(LLError::Settings::instance().getDupStderr(), "a"))
+ mStderr(llfd::open(LLError::Settings::instance().getDupStderr(), "a"))
{
this->showMultiline(true);
}
@@ -276,7 +256,7 @@ namespace {
// Check whether it's okay to use ANSI; if stderr is
// a tty then we assume yes. Can be turned off with
// the LL_NO_ANSI_COLOR env var.
- return (0 != isatty(fhfileno(stderr))) &&
+ return (0 != isatty(fileno(stderr))) &&
(NULL == getenv("LL_NO_ANSI_COLOR"));
#endif // LL_LINUX
return false;
@@ -572,16 +552,8 @@ namespace LLError
Settings::Settings():
mSettingsConfig(new SettingsConfig()),
// duplicate stderr file handle right away
- mDupStderr(fhdup(fhfileno(stderr)))
- {
- }
-
- Settings::~Settings()
+ mRedirect(NULL, stderr)
{
- // restore original stderr
- fhdup2(mDupStderr, fhfileno(stderr));
- // and close the duplicate
- fhclose(mDupStderr);
}
SettingsConfigPtr Settings::getSettingsConfig()
@@ -611,7 +583,7 @@ namespace LLError
int Settings::getDupStderr() const
{
- return mDupStderr;
+ return mRedirect.getOriginalTarget();
}
bool is_available()
diff --git a/indra/llcommon/lltempredirect.cpp b/indra/llcommon/lltempredirect.cpp
new file mode 100644
index 00000000000..1ae3116b773
--- /dev/null
+++ b/indra/llcommon/lltempredirect.cpp
@@ -0,0 +1,138 @@
+/**
+ * @file lltempredirect.cpp
+ * @author Nat Goodspeed
+ * @date 2019-10-31
+ * @brief Implementation for lltempredirect.
+ *
+ * $LicenseInfo:firstyear=2019&license=viewerlgpl$
+ * Copyright (c) 2019, Linden Research, Inc.
+ * $/LicenseInfo$
+ */
+
+// Precompiled header
+#include "linden_common.h"
+// associated header
+#include "lltempredirect.h"
+// STL headers
+// std headers
+#if !LL_WINDOWS
+# include <unistd.h>
+#else
+# include <io.h>
+#endif // !LL_WINDOWS
+// external library headers
+// other Linden headers
+
+/*****************************************************************************
+* llfd
+*****************************************************************************/
+// We could restate the implementation of each of llfd::close(), etc., but
+// this is way more succinct.
+#if LL_WINDOWS
+#define fhclose _close
+#define fhdup _dup
+#define fhdup2 _dup2
+#define fhfdopen _fdopen
+#define fhfileno _fileno
+#else
+#define fhclose ::close
+#define fhdup ::dup
+#define fhdup2 ::dup2
+#define fhfdopen ::fdopen
+#define fhfileno ::fileno
+#endif
+
+int llfd::close(int fd)
+{
+ return fhclose(fd);
+}
+
+int llfd::dup(int target)
+{
+ return fhdup(target);
+}
+
+int llfd::dup2(int target, int reference)
+{
+ return fhdup2(target, reference);
+}
+
+FILE* llfd::open(int fd, const char* mode)
+{
+ return fhfdopen(fd, mode);
+}
+
+int llfd::fileno(FILE* stream)
+{
+ return fhfileno(stream);
+}
+
+/*****************************************************************************
+* LLTempRedirect
+*****************************************************************************/
+LLTempRedirect::LLTempRedirect():
+ mOrigTarget(-1), // -1 is an invalid file descriptor
+ mReference(-1)
+{}
+
+LLTempRedirect::LLTempRedirect(FILE* target, FILE* reference):
+ LLTempRedirect((target? fhfileno(target) : -1),
+ (reference? fhfileno(reference) : -1))
+{}
+
+LLTempRedirect::LLTempRedirect(int target, int reference):
+ // capture a duplicate file descriptor for the file originally targeted by
+ // 'reference'
+ mOrigTarget((reference >= 0)? fhdup(reference) : -1),
+ mReference(reference)
+{
+ if (target >= 0 && reference >= 0)
+ {
+ // As promised, force 'reference' to refer to 'target'. This first
+ // implicitly closes 'reference', which is why we first capture a
+ // duplicate so the original target file stays open.
+ fhdup2(target, reference);
+ }
+}
+
+LLTempRedirect::LLTempRedirect(LLTempRedirect&& other)
+{
+ mOrigTarget = other.mOrigTarget;
+ mReference = other.mReference;
+ // other LLTempRedirect must be in moved-from state so its destructor
+ // won't repeat the same operations as ours!
+ other.mOrigTarget = -1;
+ other.mReference = -1;
+}
+
+LLTempRedirect::~LLTempRedirect()
+{
+ reset();
+}
+
+void LLTempRedirect::reset()
+{
+ // If this instance was default-constructed (or constructed with an
+ // invalid file descriptor), skip the following.
+ if (mOrigTarget >= 0)
+ {
+ // Restore mReference to point to mOrigTarget. This implicitly closes
+ // the duplicate created by our constructor of its 'target' file
+ // descriptor.
+ fhdup2(mOrigTarget, mReference);
+ // mOrigTarget has served its purpose
+ fhclose(mOrigTarget);
+ // assign these because reset() is also responsible for a "moved from"
+ // instance
+ mOrigTarget = -1;
+ mReference = -1;
+ }
+}
+
+LLTempRedirect& LLTempRedirect::operator=(LLTempRedirect&& other)
+{
+ reset();
+ std::swap(mOrigTarget, other.mOrigTarget);
+ std::swap(mReference, other.mReference);
+ return *this;
+}
diff --git a/indra/llcommon/lltempredirect.h b/indra/llcommon/lltempredirect.h
new file mode 100644
index 00000000000..33e05dc06b2
--- /dev/null
+++ b/indra/llcommon/lltempredirect.h
@@ -0,0 +1,91 @@
+/**
+ * @file lltempredirect.h
+ * @author Nat Goodspeed
+ * @date 2019-10-31
+ * @brief RAII low-level file-descriptor redirection
+ *
+ * $LicenseInfo:firstyear=2019&license=viewerlgpl$
+ * Copyright (c) 2019, Linden Research, Inc.
+ * $/LicenseInfo$
+ */
+
+#if ! defined(LL_LLTEMPREDIRECT_H)
+#define LL_LLTEMPREDIRECT_H
+
+// Functions in this namespace are intended to insulate the caller from the
+// aggravating distinction between ::close() and Microsoft _close().
+namespace llfd
+{
+
+int close(int fd);
+int dup(int target);
+int dup2(int target, int reference);
+FILE* open(int fd, const char* mode);
+int fileno(FILE* stream);
+
+} // namespace llfd
+
+/**
+ * LLTempRedirect is an RAII class that performs file redirection on low-level
+ * file descriptors, expressed as ints. (Use llfd::fileno() to obtain the file
+ * descriptor from a classic-C FILE*. There is no portable way to obtain the
+ * file descriptor from a std::fstream.)
+ *
+ * Instantiate LLTempRedirect with a target file descriptor (e.g. for some
+ * open file) and a reference file descriptor (e.g. for stderr). From that
+ * point until the LLTempRedirect instance is destroyed, all OS-level writes
+ * to the reference file descriptor will be redirected to the target file.
+ *
+ * Because dup2() is used for redirection, the original passed target file
+ * descriptor remains open. If you want LLTempRedirect's destructor to close
+ * the target file, close() the target file descriptor after passing it to
+ * LLTempRedirect's constructor.
+ *
+ * LLTempRedirect's constructor saves the original target of the reference
+ * file descriptor. Its destructor restores the reference file descriptor to
+ * point once again to its original target.
+ */
+class LLTempRedirect
+{
+public:
+ LLTempRedirect();
+ /**
+ * For the lifespan of this LLTempRedirect instance, all writes to
+ * 'reference' will be redirected to 'target'. When this LLTempRedirect is
+ * destroyed, the original target for 'reference' will be restored.
+ *
+ * Pass 'target' as NULL if you simply want to save and restore
+ * 'reference' against possible redirection in the meantime.
+ */
+ LLTempRedirect(FILE* target, FILE* reference);
+ /**
+ * For the lifespan of this LLTempRedirect instance, all writes to
+ * 'reference' will be redirected to 'target'. When this LLTempRedirect is
+ * destroyed, the original target for 'reference' will be restored.
+ *
+ * Pass 'target' as -1 if you simply want to save and restore
+ * 'reference' against possible redirection in the meantime.
+ */
+ LLTempRedirect(int target, int reference);
+ LLTempRedirect(const LLTempRedirect&) = delete;
+ LLTempRedirect(LLTempRedirect&& other);
+
+ ~LLTempRedirect();
+
+ LLTempRedirect& operator=(const LLTempRedirect&) = delete;
+ LLTempRedirect& operator=(LLTempRedirect&& other);
+
+ /// returns (duplicate file descriptor for) the original target of the
+ /// 'reference' file descriptor passed to our constructor
+ int getOriginalTarget() const { return mOrigTarget; }
+ /// returns the original 'reference' file descriptor passed to our
+ /// constructor
+ int getReference() const { return mReference; }
+
+private:
+ void reset();
+
+ int mOrigTarget, mReference;
+};
+
+#endif /* ! defined(LL_LLTEMPREDIRECT_H) */
--
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