cap_get_flag - Linux

Overview

cap_get_flag is a command-line tool used to retrieve the value of a capability flag associated with a process or file descriptor. It’s commonly used for troubleshooting and debugging purposes, as well as for managing capabilities in applications.

Syntax

cap_get_flag [-hv] [--process-id <pid>] [--file-descriptor <fd>] <flag>

Options/Flags

• -h, –help: Display help information.
• -v, –verbose: Print additional information about the capability flag.
• –process-id : Get the capability flag for the process with the specified PID.
• –file-descriptor : Get the capability flag for the file descriptor associated with the given file descriptor number.
• : The capability flag to retrieve. See proc(5) for a list of available flags.

Examples

Get the effective capabilities of the current process:

cap_get_flag CAP_SYS_ADMIN

Get the permitted capabilities of a specific process:

cap_get_flag --process-id 1234 CAP_DAC_OVERRIDE

Get the inheritable capabilities for a file descriptor:

cap_get_flag --file-descriptor 3 CAP_CHOWN

Common Issues

• Permission denied: Ensure that the user running the command has sufficient permissions to retrieve the capability flag.
• Invalid flag: Check that the specified capability flag is valid.
• Invalid PID or file descriptor: Confirm that the provided PID or file descriptor is valid and corresponds to an existing process or file descriptor.

Integration

cap_get_flag can be used in conjunction with other commands to manage capabilities, such as:

• capset: Set the capabilities of a process or file descriptor.
• cap_drop: Drop specific capabilities from a process.
• getcap: Retrieve the capabilities associated with a file.

Related Commands

• getcap(1)
• capset(1)
• cap_drop(1)