1 files changed, 165 insertions, 0 deletions
diff --git a/src/utils/log.cpp b/src/utils/log.cpp
new file mode 100644
index 0000000..d26f053
--- /dev/null
+++ b/src/utils/log.cpp
@@ -0,0 +1,165 @@
+//------------------------------------------------------------------------------
+// Author: Pavel Karneliuk
+// Description: Reentrant logger implementation
+// Copyright (c) 2013 EPAM Systems
+//------------------------------------------------------------------------------
+/*
+    This file is part of Nfstrace.
+
+    Nfstrace is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, version 2 of the License.
+
+    Nfstrace is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Nfstrace.  If not, see <http://www.gnu.org/licenses/>.
+*/
+//------------------------------------------------------------------------------
+#include <cstdarg>
+#include <cstdio>
+#include <cerrno>
+#include <iostream>
+#include <stdexcept>
+#include <system_error>
+
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "utils/log.h"
+#include "utils/out.h"
+//------------------------------------------------------------------------------
+/*  http://www.unix.org/whitepapers/reentrant.html
+    The POSIX.1 and C-language functions that operate on character streams
+    (represented by pointers to objects of type FILE) are required by POSIX.1c
+    to be implemented in such a way that reentrancy is achieved
+    (see ISO/IEC 9945:1-1996, §8.2). This requirement has a drawback; it imposes
+    substantial performance penalties because of the synchronization that must
+    be built into the implementations of the functions for the sake of reentrancy.
+*/
+//------------------------------------------------------------------------------
+namespace NST
+{
+namespace utils
+{
+
+static FILE* log_file {::stderr};
+static bool  own_file {false};
+
+namespace // unnanmed
+{
+
+static std::string get_pid()
+{
+    char buff[8]={'\0'};
+    sprintf(buff,"%ld",(long)getpid());
+    return std::string{buff};
+}
+
+static FILE* try_open(const std::string& file_name)
+{
+    FILE* file {fopen(file_name.c_str(), "w")};
+    if(file == nullptr)
+    {
+        throw std::system_error{errno, std::system_category(),
+                                       "Error in opening file."};
+    }
+    chmod(file_name.c_str(), S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
+    if(flock(fileno(file), LOCK_EX | LOCK_NB))
+    {
+        fclose(file);
+        throw std::system_error{errno, std::system_category(),
+                                       "Log file already locked"};
+    }
+    return file;
+}
+
+} // namespace unnamed
+
+Log::Global::Global(const std::string& path)
+{
+    const std::string log_path{"/tmp/nfstrace"};
+
+    if(log_file != ::stderr)
+    {
+        throw std::runtime_error{"Global Logger already have been created"};
+    }
+
+    if(path.empty()) return;
+
+    struct stat s;
+    if(stat(log_path.c_str(), &s))            // check destination folder exists
+    {
+        if(mkdir(log_path.c_str(), ALLPERMS)) // create directory for nfs logs
+        {
+            throw std::system_error{errno, std::system_category(),
+                "Can't create log directory."};
+        }
+    }
+    std::string tmp{log_path + '/' + path + ".log"};
+    FILE* file {nullptr};
+    try
+    {
+        file = try_open(tmp);
+    }
+    catch(std::system_error& err)
+    {
+        tmp = log_path + '/' + path + '-' + get_pid() + ".log";
+        file = try_open(tmp);
+    }
+    if(utils::Out message{})
+    {
+        message << "Log folder: " << log_path;
+    }
+
+    log_file = file;
+    own_file = true;
+}
+
+Log::Global::~Global()
+{
+    if(own_file)
+    {
+        flock(fileno(log_file), LOCK_UN);
+        fclose(log_file);
+        own_file = false;
+        log_file = ::stderr;
+    }
+}
+
+Log::Log()
+: std::stringbuf {ios_base::out}
+, std::ostream   {nullptr}
+{
+    std::stringbuf::setp(buffer, buffer+sizeof(buffer));
+    std::ostream::init(static_cast<std::stringbuf*>(this));
+    std::ostream::put('\n');
+}
+
+Log::~Log()
+{
+    size_t len = pptr() - pbase();
+    fwrite(pbase(), len, 1, log_file);
+}
+
+void Log::message(const char* format, ...)
+{
+    va_list args;
+    va_start(args, format);
+    vfprintf(log_file, format, args);
+    va_end(args);
+}
+
+void Log::flush()
+{
+    fflush(log_file);
+}
+
+} // namespace utils
+} // namespace NST
+//------------------------------------------------------------------------------