You have to seteuid to the user, get the group, then return to uid 0. Because setuid() will change all of the uid settings (real, effective, etc.) you may think you can call seteuid() instead, so that you can later call setuid to root. But seteuid() does not change groups. Which does not work for what you want....
So, you have to exec(), setuid() to nobody, write the result of getgroups to shared memory, exit the child process.
IMO, It is probably less complicated to try this:
Then parse out the uids, usually nobody is a single group so one atoi call returns the group.
Last edited by jim mcnamara; 04-28-2011 at 02:15 PM..
Reason: change -g to -R see red text
when /var directory of my machine gets filled up (85%) i removed some old logs. but after cleaning df -k command still shows that /var is still 85% full.
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What's the best way to find out how much memory is being used/available? I tried using free, but I didn't quite understand the output. Can someone explain it?
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total used free shared buffers cached
Mem: 16304536 16256376 48160 0 ... (6 Replies)
What is amount of free RAM i have now?
total used free shared buffers cached
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Above is the output of... (1 Reply)
how can I find cpu usage memory usage swap usage and
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As I am new to Linux server, I am facing some doubts like: On linux server virtual memory usage goes to 99%, but I have Threshold limit of 95%. So it crossed the threshold limit and alarmd.
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Hi,
My server is Centos 6 i686.
Is it possible get an openssl download from this site
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and use it on 32 bit platforms also?
Thx,
Aigini (5 Replies)
Discussion started by: anaigini45
5 Replies
LEARN ABOUT REDHAT
getgroups
GETGROUPS(2) Linux Programmer's Manual GETGROUPS(2)NAME
getgroups, setgroups - get/set list of supplementary group IDs
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
int getgroups(int size, gid_t list[]);
#include <grp.h>
int setgroups(size_t size, const gid_t *list);
DESCRIPTION
getgroups
Up to size supplementary group IDs are returned in list. It is unspecified whether the effective group ID of the calling process is
included in the returned list. (Thus, an application should also call getegid(2) and add or remove the resulting value.) If size is
zero, list is not modified, but the total number of supplementary group IDs for the process is returned.
setgroups
Sets the supplementary group IDs for the process. Only the super-user may use this function.
RETURN VALUE
getgroups
On success, the number of supplementary group IDs is returned. On error, -1 is returned, and errno is set appropriately.
setgroups
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
ERRORS
EFAULT list has an invalid address.
EPERM For setgroups, the user is not the super-user.
EINVAL For setgroups, size is greater than NGROUPS (32 for Linux 2.0.32). For getgroups, size is less than the number of supplementary
group IDs, but is not zero.
NOTES
A process can have up to at least NGROUPS_MAX supplementary group IDs in addition to the effective group ID. The set of supplementary group
IDs is inherited from the parent process and may be changed using setgroups. The maximum number of supplementary group IDs can be found
using sysconf(3):
long ngroups_max;
ngroups_max = sysconf(_SC_NGROUPS_MAX);
The maximal return value of getgroups cannot be larger than one more than the value obtained this way.
The prototype for setgroups is only available if _BSD_SOURCE is defined (either explicitly, or implicitly, by not defining _POSIX_SOURCE or
compiling with the -ansi flag).
CONFORMING TO
SVr4, SVID (issue 4 only; these calls were not present in SVr3), X/OPEN, 4.3BSD. The getgroups function is in POSIX.1. Since setgroups
requires privilege, it is not covered by POSIX.1.
SEE ALSO initgroups(3), getgid(2), setgid(2)Linux 2.0.32 1997-12-10 GETGROUPS(2)