How to use the command 'extrace' (with examples)

The ’extrace’ command is a tool for tracing ’exec()’ calls in a program. It provides useful information about program executions and allows the user to track various process activities. This article will illustrate several use cases of the ’extrace’ command and provide examples for each.

Use case 1: Trace all program executions occurring on the system

Code:

sudo extrace

Motivation: By running sudo extrace command, all program executions occurring on the system are traced. This can be useful for monitoring system activities, identifying resource usages, and troubleshooting issues related to program execution.

Explanation:

• sudo: This command is used to execute ’extrace’ as the superuser, granting the necessary permissions to trace all program executions.
• extrace: The main command that is executed. It traces exec() calls in programs.

Example output:

PID#13  (process-name) path-to-executed-file
...

Use case 2: Run a command and only trace descendants of this command

Code:

sudo extrace command

Motivation: Sometimes, it is only necessary to trace the descendants of a specific command to analyze their behavior or execution pattern. This use case allows users to focus on a specific command and its child processes.

Explanation:

• sudo: The superuser privileges are required to execute ’extrace'.
• extrace: The main command to trace exec() calls.
• command: The specific command that will be run and whose descendants will be traced.

Example output:

PID#13  (process-name) path-to-executed-file
...

Use case 3: Print the current working directory of each process

Code:

sudo extrace -d

Motivation: The current working directory (CWD) of a process can have significant implications on its functionality. By printing the CWD of each process, users can understand the file system context in which the processes operate.

Explanation:

• sudo: Superuser privileges are required.
• extrace: The command responsible for tracing exec() calls.
• -d: This flag instructs ’extrace’ to print the current working directory of each process.

Example output:

PID#13  (process-name) path-to-executed-file  [CWD: /path/to/current_directory]
...

Use case 4: Resolve the full path of each executable

Code:

sudo extrace -l

Motivation: When troubleshooting or analyzing a system, resolving the full path of an executable can provide crucial information about its origin and version. This use case allows users to obtain the complete path of each executable being executed.

Explanation:

• sudo: Execution as the superuser is required.
• extrace: The command used to trace exec() calls.
• -l: This option instructs ’extrace’ to resolve and display the full path of each executable.

Example output:

PID#13  (process-name) /path/to/executable
...

Use case 5: Display the user running each process

Code:

sudo extrace -u

Motivation: Knowing which user is running a specific process can help in system monitoring, user-specific debugging, and security auditing. This use case allows users to identify the user associated with each traced process.

Explanation:

• sudo: Execution as the superuser is required.
• extrace: The main command to trace exec() calls.
• -u: This flag instructs ’extrace’ to display the user running each process.

Example output:

PID#13  (process-name) [User: username]
...

Conclusion:

The ’extrace’ command is a powerful tool for tracing exec() calls and gaining insights into program executions on a system. By exploring these various use cases, users can effectively monitor and analyze system activities, understand process behaviors, and troubleshoot issues arising from program execution.