Add cmake build instructions

1 files changed, 61 insertions, 0 deletions

diff --git a/src/io.h b/src/io.h
new file mode 100644
index 0000000..87778ec
--- /dev/null
+++ b/src/io.h
@@ -0,0 +1,61 @@
+#ifndef CHANGE_IO_H_
+#define CHANGE_IO_H_
+
+#include <unistd.h>
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+
+#include <cstring>
+
+namespace io {
+
+class FileDescriptorGuard {
+	public:
+		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);
+		}
+
+		operator int() {
+			return this->fd;
+		}
+
+	private:
+		int fd;
+
+};
+
+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);
+}
+
+}
+
+#endif  // CHANGE_IO_H_