From ceb01fb33a039d4f315c9aa9217320be44cefa2d Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Sun, 18 Oct 2015 17:19:55 +0200
Subject: Move io and logging functionality into separate namespaces

---
 change_log.cc | 94 ++++++++++++-----------------------------------------------
 1 file changed, 18 insertions(+), 76 deletions(-)

(limited to 'change_log.cc')

diff --git a/change_log.cc b/change_log.cc
index 58ba0db..dc245da 100644
--- a/change_log.cc
+++ b/change_log.cc
@@ -2,55 +2,16 @@
 #define _GNU_SOURCE
 #endif
 
-#include <unistd.h>
-#include <dlfcn.h>
-#include <fcntl.h>
-#include <sys/stat.h>
-
-#include <ext/stdio_filebuf.h>
-
-#include <cstring>
-#include <iostream>
-#include <utility>
+#include <memory>
 #include <functional>
 #include <unordered_set>
-#include <memory>
-
-struct FileDescriptorGuard {
-	FileDescriptorGuard(const std::string& path) {
-		this->fd = open(path.c_str(), O_WRONLY | O_APPEND);
-
-		if ( !this->fd ) {
-			this->fd = STDERR_FILENO;
-		}
-	}
-
-	~FileDescriptorGuard() {
-		close(this->fd);
-	}
-
-	int fd;
-};
-
-class LogGuard {
-	public:
-		LogGuard(const int target_fd):
-			buffer(target_fd, std::ios::out),
-			stream(&this->buffer) { }
-
-		void append(const std::string& msg) {
-			this->stream << msg << std::endl;
-		}
-
-	private:
-		__gnu_cxx::stdio_filebuf<char> buffer;
-		std::ostream                   stream;
-};
 
-static std::unordered_set<std::string> tracked_files;
+#include "io.h"
+#include "utility.h"
 
-static std::unique_ptr<FileDescriptorGuard> fd_guard;
-static std::unique_ptr<LogGuard>            log;
+static std::unique_ptr<std::unordered_set<std::string>> tracked_files;
+static std::unique_ptr<io::FileDescriptorGuard>         fd_guard;
+static std::unique_ptr<utility::Logger>                 log;
 
 template <class Result, typename... Arguments>
 std::function<Result(Arguments...)> get_real_function(
@@ -66,11 +27,15 @@ std::function<Result(Arguments...)> get_real_function(
 
 void init() __attribute__ ((constructor));
 void init() {
+	tracked_files = std::make_unique<std::unordered_set<std::string>>();
+
 	if ( getenv("CHANGE_LOG_TARGET") != NULL ) {
-		fd_guard = std::make_unique<FileDescriptorGuard>(getenv("CHANGE_LOG_TARGET"));
-		log      = std::make_unique<LogGuard>(fd_guard->fd);
+		fd_guard = std::make_unique<io::FileDescriptorGuard>(
+			getenv("CHANGE_LOG_TARGET")
+		);
+		log      = std::make_unique<utility::Logger>(fd_guard->fd);
 	} else {
-		log      = std::make_unique<LogGuard>(STDERR_FILENO);
+		log      = std::make_unique<utility::Logger>(STDERR_FILENO);
 	}
 }
 
@@ -78,42 +43,19 @@ void exit(int status) {
 	get_real_function<void, int>("exit")(status);
 }
 
-std::string get_file_name(int fd) {
-	char proc_link[20];
-	char file_name[256];
-
-	snprintf(proc_link, sizeof(proc_link), "/proc/self/fd/%d", fd);
-	const ssize_t name_size = readlink(proc_link, file_name, sizeof(file_name));
-
-	if ( name_size > 0 ) {
-		file_name[name_size] = '\0';
-
-		return std::string(file_name);
-	} else {
-		return std::string();
-	}
-}
-
-bool is_regular_file(int fd) {
-	struct stat fd_stat;
-	fstat(fd, &fd_stat);
-
-	return S_ISREG(fd_stat.st_mode);
-}
-
 bool is_tracked_file(const std::string& file_name) {
-	return tracked_files.find(file_name) != tracked_files.end();
+	return tracked_files->find(file_name) != tracked_files->end();
 }
 
 bool track_file(const std::string& file_name) {
-	return tracked_files.emplace(file_name).second;
+	return tracked_files->emplace(file_name).second;
 }
 
 ssize_t write(int fd, const void* buffer, size_t count) {
 	static auto real_write = get_real_function<ssize_t, int, const void*, size_t>("write");
 
-	if ( is_regular_file(fd) ) {
-		const std::string file_name{ get_file_name(fd) };
+	if ( io::is_regular_file(fd) ) {
+		const std::string file_name{ io::get_file_name(fd) };
 
 		if ( !is_tracked_file(file_name) ) {
 			track_file(file_name);
@@ -155,7 +97,7 @@ int unlinkat(int dirfd, const char* path, int flags) {
 	if ( dirfd == AT_FDCWD ) {
 		log->append("removed '" + std::string(path) + "'");
 	} else {
-		log->append("removed '" + get_file_name(dirfd) + path + "'");
+		log->append("removed '" + io::get_file_name(dirfd) + path + "'");
 	}
 
 	return real_unlinkat(dirfd, path, flags);
-- 
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