Real, effective and saved user id in C program

8 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

Regarding real example of user of semicolon(;) and + in find/exec command.

Hello All, Was recently working on an requirement where we have to search files more than a specific number, following is the example on same. Let's say file names are test_40000.txt,test_40001.txt and so on till test_99999.txt. Now requirement was to search from find command only those...

2. UNIX for Dummies Questions & Answers

[Solved] effective user id upon exec

Hello all. Despite the exec man page, the exec system call seems to turn my effective-user-id into my real-user-id. I coded and compiled 2 very simple c programs as user 1 (uid=501) The first one (A) prints real and effective user IDs and then execs the second one (B), which in turn prints...

3. UNIX for Dummies Questions & Answers

Real and Effective IDs

Can anyone explain me in details of Real and Effective IDs

4. Solaris

Help with who am i . Not displaying real user

Hi I'm trying to get the real username of any user running as root on my server. On one of my server running Sol 10, if I su to root and run who am i, it displays my username. which is what I want. But when I run it on another server, this time on Sol 8, it displays root as the user. Is...

5. Shell Programming and Scripting

In real time - what user connects or disconnect

Write a tool that will be displayed in real time, what user connects or disconnects from a system that uses this tool :)) Maybe anyone can help me?

6. Shell Programming and Scripting

how to get real user name

I know that in order to get a real user name I should use the following command: cut -d: -f5 /etc/passwd. But how can I get the real user name for those users who are currently logged in to the system??? :confused: Can somebody help me???

7. Post Here to Contact Site Administrators and Moderators

I'm need effective program for advertising internet-projects

Anybody can recomend me websites for purchase professional software for website advertising? It's really important to me. Please, help. Thanks P.S. Also I need for advertising soft that can break CAPTHA's, can mass posting, can sort sites by Google PageRank (PR) and others. Also, I'm interested...

8. Cybersecurity

Changing effective user

I would like to give execution rights for a script to one user. (that's the easy part...) When that user is running the script, I would like the effective user ID to be that of the file-owner. Is this possible?

LEARN ABOUT REDHAT

setreuid

SETREUID(2)						     Linux Programmer's Manual						       SETREUID(2)

NAME

       setreuid, setregid - set real and/or effective user or group ID

SYNOPSIS

       #include <sys/types.h>
       #include <unistd.h>

       int setreuid(uid_t ruid, uid_t euid);
       int setregid(gid_t rgid, gid_t egid);

DESCRIPTION

       setreuid  sets real and effective user IDs of the current process.  Unprivileged users may only set the real user ID to the real user ID or
       the effective user ID, and may only set the effective user ID to the real user ID, the effective user ID or the saved user ID.

       Supplying a value of -1 for either the real or effective user ID forces the system to leave that ID unchanged.

       If the real user ID is set or the effective user ID is set to a value not equal to the previous real user ID, the saved user ID will be set
       to the new effective user ID.

       Completely analogously, setregid sets real and effective group ID's of the current process, and all of the above holds with "group" instead
       of "user".

RETURN VALUE

       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       EPERM  The current process is not the super-user and changes other than (i) swapping the effective user	(group)  ID  with  the	real  user
	      (group)  ID,  or (ii) setting one to the value of the other or (iii) setting the effective user (group) ID to the value of the saved
	      user (group) ID was specified.

NOTES

       Setting the effective user (group) ID to the saved user ID is possible since Linux 1.1.37 (1.1.38).

CONFORMING TO

       BSD 4.3 (the setreuid and setregid function calls first appeared in 4.2BSD).

SEE ALSO

       getuid(2), getgid(2), setuid(2), setgid(2), seteuid(2), setresuid(2)

Linux 1.1.38							    1994-08-02							       SETREUID(2)

Programming