I would like to trace a user's activity by monitoring system calls. Is there a way to use strace such that at startup it will begin tracing all system calls? Or is there any other method to automatically trace the system calls used during a user's session automatically without having to call strace manually?
View 6 RepliesWhat is the real difference between system calls and normal function calls. Ultimately function calls too would be passed to kernel for some or the other work.
View 7 Replies View RelatedI'm new to C language and some help finding places in the following code where a system call is made and error checking is not done. I found one but since I don't know C language at all I'm not exactly sure what else to look for. Link to my file: [URL]...
I found one and added error checking:
if (setoutpipe){
//Changes: Added error checking to the system call close()
//Orginal Code: close(pidefd[1]);
if(close(pipefd[1] != 0){
fprintf(stderr, "Could not close piple.
");
exit(255);
}
I want a log or live data that discloses the system calls an application makes. I have used strace but can't find a guide for it that is decent. I'm interested in knowing the calls made after user intervention like opening a menu and so on. If you run (strace application_name) it is static. What good is this? When does strace make this file? When is this log produced?
View 4 Replies View RelatedI've been receiving a ton of calls from telemarketers and political callcenters. What would be the simplest way to use Ubuntu to automatically drop calls incoming from blacklisted numbers?
I have Comcast Digital Voice service, which is technically VOIP but I think it interfaces with modems themselves just like any other phone service would.
I have a dedicated Ubuntu server sitting next to a phone jack already, so I'd like to use that if possible.
I've seen FreePBX and Asterisk, and hear that they can do the job. However, I haven't been able to tell just how easily they could be set up. It sounds like they might require me to get rid of all my phones and use soft phones instead... Does anybody know if it is as simple as buying a voice modem and configuring a PBX software to interface with it?
I've implemented a few custom system calls in my Ubuntu kernel, but I'm having some issues with the return values. Each function returns a variety of non-negative integers depending on which error is encountered. However, when I'm testing the system calls, the only negative value that gets returned to the user program is -1, regardless of what I have in the code.
Is there some special path I have to take to get the proper return values?
I need to include variables in a system() call. This is that I have:
[code]#include <iostream>
#include <stdio.h>
#include <stdlib.h>
using namespace std;
[Code]....
P.S.: I know this is a pointless redundant program, but it's part of a larger project learning process.
My data center informed me that my shared web hosting server is producing a massive attack. Attack against who? how? etc?... well.. other than "your server is generating an attack of over 150,000 UDP connections", they did not specify the target IP, nor the specific port. The attacks usually run for less than 5 minutes and pose a threat on the datacenter's firewall itself (from within).
I ran various searches on my server and came up with nothing. (over 300 websites with PHP in 25GB of data, database etc).
I do not allow any shell/bash other than myself, so no other logins are available. (I re-checked /etc/passwd for any bash).
I believe that there is probably some php fsckopen call or something to that degree that responds to a call from an external server. To make it easier to diagnose the problem and then stopping it, I need your assistance developing a simple tracing tool, methodology.
I have wireshark installed on the server.
My thoughts on how to capture this attack (which occurs at random) is as follow:
1. run a service that greps and count the UDP connections currently on the server and does this every 60 seconds. ( a simple one minute cron is enough).
netstat -a |grep UDP -cw
2. Currently the output shows: 0 (zero).
3. I do run a DNS server that can be queried, so I expect to see some UDP calls every so often. However, this is probably going to occur at < 50 entries.
4 . run this logic if no high loads on the server.
If servers load is < 3.00
{
If ( netstat -a |grep UDP -cw ) > 50
{
./tshark > wireshark.hacker.trace<timestamp>.txt;
email me an alert that "hey wireshark was triggered";
sleep (15)
killall -9 tshark
}
}
what is the command to show the recent system calls in the OS?
View 2 Replies View Relatedi upgraded to 10.04 and when i connect my psp system it calls it 9"e instead of PSP wich it used to in 9.04. how to rename it?
View 2 Replies View RelatedI know there is a way to call winapi in runtime in windows. I want to ask how can I call a system call in gcc in runtime (when I don't know what it can be)? I don't mean syscall that I think is for calling only system calls and not library functions.
View 4 Replies View RelatedWhat is the difference between creating a "regular" user and creating a "system" user on Linux?
For example:
Code:
adduser john
Code:
adduser --system john
Similarly it seems there are normal groups and system groups. Doing an internet search and reading man pages does not give much information on the whole concept of system and regular user/group.
I'm trying to produce a alphabetic, non-repetitive list of all System service calls in all c files located in a folder. Here's what I got so far.
grep -ow '[A-Za-z]*SYS[$][A-Za-z]*' *.c | sort
Which produces all system service calls in alphabetic order I just need to find out how to make it non-repetitive.
I am working with fedora 6 , i386 architecture.I am trying to write on keyboard port via program.On inspation i come to know that 0x0060 to 0xz006f are used for keyboard in linux 2.6 kernel in the i/o space from kernel.
#include<sys/io.h>
#include<stdio.h>
#include</usr/lib/syslinux/com32/include/sys/io.h>
#include<unistd.h>
//#define
[Code]...
How to find, what are the files (system & user) created after login to the system in RHEL 5.0?
Any single command available?
I often get responses from people who first say: "Are you sure? You want your network to be exposed to the outside world?" I am not experimenting on a Production Server of NASA or any Security Concern Department. Friends, there is no harm in experimenting on your personal computer or on a test computer which is isolated from the production environment. Look at hackers! What do they do? If they don't know how security is breached then how would they come up with security measures?
If my question reads... "How to let any user perform Administrative Tasks on a Linux System irrespective of his/her privileges on that particular system?" then I would not get the right answers in the first place. They will say... "You are letting everyone destroy your system... are you sure you want to do that?" My question is: Why should we restrict ourselves from experimenting even if it sounds weird to other people?
I give you an example where it is desirable to let an unprivileged user perform certain tasks. You want to know if there are any employees in your office who are storing videos in their home directory and filling up the disk space to a great amount. You have a department called "Command Center or Data Center Operations or Help Desk" call it whatever you would, whose work is to monitor such activities, and you create an account "monitor" for them to monitor such activities but they are not able to do them:
[Code]..
I need to write a script. In which, the 2nd part commands need to run under another bash shell environment.The enter_antoher_bash_env.sh will setup a new shell environment, call "bash". The rest commands need to run under the new env. (I cannot change this script too. )If I run these command one by one manually, it works of course. If I put them into a script, enter_another_bash_env.sh won't return because it calls "bash" command inside.
View 10 Replies View RelatedFor system calls, is blocking or non-blocking default in C? Simple question, just am not seeing the answer super quickly.
View 4 Replies View RelatedI'm Pab, just like to know, How can I allow a new user to run specific software like sqlplus.
Scenario:
I have an oradb@database user where i can execute sqlplus /nolog command, but when i created a new user named allan@database the bash says....-bash:sqlplus: command not found.
Some context: I'm calling some functions from within a C program and want to measure how long they take to execute. I've done this successfully, calling printf to print the results to the screen. This is reasonably fast. Ideally I'd like these to be dumped to a file, but fprintf presumably has some overhead since it writes to disk? Unless the data is buffered by the kernel and flushed later? What kind of delay can I expect before fprintf returns?
If I redirect the stdout to a file when I instantiate the binary as a process, will calls to printf also experience any overhead from redirection to a file? My aim here is to capture all data in a file, with the minimal amount of coding and effort, but with minimal impact in terms of time overheads for printf calls.
Can someone tell me what the number '2' refers to in function calls, for example fork(2).
View 3 Replies View RelatedWhat is the value to set unlimited quota for system user in linux?
View 1 Replies View RelatedHow to I get linux to stop prompting me for a password and remember it? For instance, when using the root user, I always get prompted, but I would rather only be prompted once per user session.
View 1 Replies View RelatedI need create user .when user login --> system go to shutdown .I create this script :
Code:
### Shutdown Script ###
#!/bin/bash
[code]...
I am working on a program lets say programX which must run when the computer is not in use. I want to develop a monitoring program to monitor if there is user activity on the system so that it can stop the programX from running when the user is using the system and start programX when there is no user activity. Is there a way to determine this in linux?
View 4 Replies View Relatedhow to give nfs share to only one particular user in that particular system. that is for example if 192.168.0.5 has many users but i wanna make only one particular user to acces that share.
View 5 Replies View Relatedi am using rhel 5.4 , in my system mails are not coming from one user to another user.....crontab also not work...
root: mail -s "hello" james
james: no mails for james
lately i notice that when i add a new user withthe useradd and passwd command, and then try to login using this new account, am being prompted with a message,saying ' you cannot access /home/newuser. that the account doesnot have permission on his home directory. i have even tried go give the user(john) ownership over his home directory with the #chown -R john:john /home/john
View 8 Replies View RelatedIs there any way in linux that user & group security can be set ?
excluding the owner & group permissions.
Whats the best app/client for video calls in OpenSuse 11.2 or any other OpenSuse for that matter, other than Kopete or Skype?
View 1 Replies View Related