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.