File Descriptor Closure Delay Mechanism
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Solution Overview
Problem
Existing systems face issues with double closures of file descriptors, leading to incorrect resource sharing and object serving due to premature reassignment of file descriptors, causing bugs where multiple threads share the same descriptor.
Innovation Solution
Implementing a method that intercepts the close() system call using a dup2() system call to duplicate the file descriptor onto an innocuous file, ensuring atomic closure and reopening, and introducing a threshold delay to prevent rapid reassignment, thereby preventing double closures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a file descriptor is closed and immediately reassigned to another resource, then resource turnover and productivity are improved, but the risk of double closure bugs increases when multiple threads share the same descriptor
Solution Approach 1:
The patent applies preliminary action by proactively delaying the closure of file descriptors using a delay queue and timeout mechanism. Before a file descriptor is closed and reassigned, it is scheduled for closure after a delay period, allowing time for any delayed operations to complete. This prevents double closure bugs while maintaining resource turnover by ensuring descriptors are eventually closed and reassigned.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a delay queue and timeout manager that mediates between the close() system call and the actual file descriptor closure. This intermediary layer tracks closed descriptors, delays their actual closure, and coordinates reassignment, preventing race conditions while enabling resource reuse.
2Reliability
If a threshold delay is introduced before closing file descriptors, then double closure prevention is improved, but system complexity and processing time increase
Solution Approach 1:
The patent applies self-service by implementing a timeout-based automatic closure mechanism. File descriptors are added to a delay queue with timeout values, and the system automatically processes closures after the specified delay without requiring manual intervention or complex coordination logic. This reduces system complexity while maintaining reliability.
Solution Approach 2:
The patent changes the temporal parameter of file descriptor closure by introducing a delay queue with timeout values. Instead of immediate closure, descriptors are scheduled for closure after a configurable delay period. This parameter change simplifies the closure management system by using time-based scheduling rather than complex coordination protocols.
3Reliability
If file descriptors are held open longer to prevent double closures, then reliability is improved, but resource availability and productivity decrease
Solution Approach 1:
The patent applies dynamics by implementing a flexible, configurable timeout mechanism for file descriptor closure. The delay duration can be adjusted based on the specific use case and operational requirements. This dynamic approach allows the system to balance reliability and productivity by tuning the timeout parameters to match actual operational patterns.
Solution Approach 2:
The patent uses periodic action through timeout-based scheduled closure of file descriptors. Descriptors are closed at predetermined intervals after the close() call, creating a rhythmic pattern of closure and reassignment. This periodic approach ensures reliability while maintaining productivity by systematically managing descriptor availability.
Data Source
AI summary
This disclosure describes systems, methods, and devices related to preventing multiple closures of a file descriptor. A method may include identifying a close( ) system call requesting closure of a file descriptor that is opened to a first file; generating, based on the close( ) system call, prior to closing the file descriptor, a dup2( ) system call for the file descriptor; releasing, based on the dup2( ) system call, the first file from the file descriptor; opening, based on the dup2( ) system call, the file descriptor to a second file; determining that a threshold delay from receipt of the close( ) system call has expired; and closing, based on the expiration of the threshold delay, the file descriptor.