function::task_euid - Linux

Overview

The task_euid() function in Linux gets the effective user ID of the process specified by the tid parameter. This allows you to determine which user a process is running as, regardless of any set-user-ID bits that may be set on the process executable.

Syntax

int task_euid(pid_t tid);

Parameters

  • tid: The ID of the process whose effective user ID you want to get.

Return Value

The task_euid() function returns the effective user ID of the process specified by the tid parameter, or -1 if an error occurs.

Options/Flags

None.

Examples

#include <linux/sched.h>
#include <stdio.h>

int main() {
  pid_t tid = getpid();
  int euid = task_euid(tid);
  if (euid == -1) {
    perror("task_euid");
    return 1;
  }

  printf("The effective user ID of the current process is %d.\n", euid);
  return 0;
}

Common Issues

One common issue that you may encounter when using the task_euid() function is that it requires the CAP_SYS_NICE capability to be enabled in order to get the effective user ID of a process that does not belong to you. If you try to use the task_euid() function without the CAP_SYS_NICE capability enabled, you will get a EPERM error.

Integration

The task_euid() function can be used in conjunction with other Linux commands and tools to perform a variety of tasks. For example, you can use the task_euid() function to determine which user a process is running as, and then use that information to make decisions about how to handle the process.

Related Commands

  • getuid() – Gets the effective user ID of the current process.
  • geteuid() – Gets the real user ID of the current process.
  • setresuid() – Sets the real, effective, and saved user IDs of the current process.