General :: Regarding Fork() Multiple Process?
Aug 2, 2011trying to fork multiple child but the program does not go as i want...
My code :
Code:
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
[code].....
trying to fork multiple child but the program does not go as i want...
My code :
Code:
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
[code].....
I've a script that forks to another script.
The problem is that the child will not return to main process.
Main script "fork.sh"
Code:
The child process "smb_fork.sh"
Code:
when running it from the terminal "sh -x ./foork.sh"
Code:
My goal is via cron connect to ~100 remote winXP computers and download a single file. There fore I like to fork the process.
my code is very simple:
int pid, status;
printf("parent process id=%d, to call fork
",getpid());
if(pid=fork()<0)
[Code].....
but everytime I can only get two fork return pid=0. In parent process, the pid returned by fork() should be >0 and equal to the child process id.
I would like to run versions of Mozilla Firefox 3.6.5+ as a single process, just as it was in versions 3.6.3 and prior. The reason is that, on Linux, I am running within proxychains - which doesn't bind to forked processes. Because the plugins in versions 3.6.5+ run in a forked process I can't use proxychains to redirect Flash streams. Is there a setting in modern versions of Firefox that allow me to run plugins in the main process?
View 1 Replies View RelatedConsider the following code:
Code:
int main()
{
int i=0;
pid_t pid;
for(i=0;i<2;i++)
[code]....
I get the following output:
Parent: chid_pid=4356 i=0 parent's pid=4355
This is child 4356 i=0
This is child 4357 i=1
[code]....
I can observe instead of two children(as I expect) processes there are three. This is because child process 4356 creates its own child. Why all the messages of the type "This is child X i=Y" are concentrated one under another? How exactly fork works? Is affected by the fact that I have a dual-core processor?
I have a process running on Linux.When i do ps -eaf | grep <myProcess>, it show muliple entries for <myProcess> with different pids for each entry.Kindly tell me what could be the reason for a process having multiple pids?
View 1 Replies View Relatedi got basic knowledge about creating a single child from a parent using fork(). But when it comes into creating multiple children, i am simply stuck. I am trying to create two processes from a parent and it would wait for both two processes to finish. my attempt is as below
[Code]....
I know that fork() copies the address space of the calling process. Say, however, i have a linked list allocated. Will the list be copied over to the child process's space? If so, i would have to free them in the child process as well as the parent process, correct? Or will the variables be copied but not be pointing to any valid address? Or would it just kind of not do anything?example:
Code:
struct ll_ex {
struct ll_ex * next;
[code]....
Code:
int main()
{
int pi;
int i=10;
pid=fork();
[code]....
Q 1. The value of the variable pid returned by the fork() function will be greater than 0 in the parent process and equal to zero in the child process? but during forking, there values are exactly copied so what's went wrong here?
Q 2. "changes to the variable in one process is not reflected in the other process" why it is so? >> Even if we have variable i declared as a pointer or a global it wont make a difference.
Code:
int main()
{
int i, pid;
i=10;
printf("before fork i is %d
[code]....
Q. Through this program it is clear that both process is using the data from the same location, so where's the original value is residing when the child process is in execution.?
As an assignment i was doing a program to create two process using fork and pass messages between them using message queue.Did it worked well until my friend tried to copy it using scp.suddenly all hell broke loose as processes without ran syncronisation ie. in tech terms the process just wont wait wen a message queue is empty.it keeps on executing randomly.but after a reboot .. everything worked fine. until again i tried to do scp on my system on purpose. and again the program just went mad.
View 3 Replies View RelatedSuppose I have a server, foo, that runs on port 5555. I can make one connection to it at a time on that port. I want xinetd to fork new instances of foo so multiple clients can connect to it.
Here's a configuration entry:
1) How does xinetd fork a new instance of foo when a previous instance is already listening on port 5555? Wouldn't the new process fail to launch because port 5555 is already in use by the previous process?
2) Suppose five clients connect simultaneously, and xinetd forks five instances of foo. When the clients disconnect, does xinetd leave all five instances running?
I have a doubt about signals in C programming. I have done this little program to explain it. It creates a child process with fork and, when the child ends, receives the SIGCHLD signal and wait for its termination.Ok, quite easy, BUT when I execute this code the SIGCHLD signal is received twice, first as an error (returns -1) and the second one to finish the child process.I don't understand the meaning of the first received signal. Why is it generated? Is the code wrong? (if you add the SIGINT and press Ctrl+C during the execution it also receives two signals instead of one)
Code: #include <stdio.h>
#include <unistd.h>
#include <string.h>
[code]....
How can we run the linux process like tar on multiple core? For example if we want to build the kernel we can use -j4 to distribute process of 4 different core. Is it possible to run long time consuming process on mulitple core?
View 1 Replies View RelatedI have some random files in a folder. I want to rename all of the files in a batch process. I have a text file that contains the Currentname of all the files in the folder, as well as a text file with all of the Newname of files in the folder. I want to replace Currentnames with Newnames.
For example, here are the names of the files in the folder:
1.mp4
2.mp4
3.mp4
I have a text file with the Currentname of all the files in the folder:
1.mp4
2.mp4
3.mp4
I have a text file with the proper Newname of the file:
a.mp4
b.mp4
c.mp4
I want to rename Currentname with Newname in the folder. So when I go to the folder the Newname of the files are:
a.mp4
b.mp4
c.mp4
First post from a very new Linux user....I am trying to create a BASH script that will allow user to provide multiple directory names, Checks if the directory exists and if not create the directory.
I am using the following code:
Which works fine as long as the user enters a single directory name. How can I modify this so it will process all directory names user enters on the read response?
I have created a simple download schedular with source-code give below :
---------------------record_strokes.sh-------------------
touch /home/student/packs/lynx/logfile
lynx -cmd_log /home/student/packs/lynx/logfile
[code]....
1) Write a C program using the fork() system call that that generates the Fibonacci sequence in the child process. The number of the sequence will be provided in the command line. For example, if 5 is provided, the first five numbers in the Fibonacci sequence will be output by the child process. Because the parent and child processes have their own copies of the data, it will be necessary for the child to output the sequence. Have the parent invoke the wait() call to wait for the child process to complete before exiting the program. Perform necessary error checking to ensure that a non-negative number is passed on the command line.
2) Repeat the preceding exercise, this time using the CreateProcess () in the Win32 API. In this instance, you will need to specify a separate program to be invoked from CreateProcess(). It is this separate program that will run as a child process outputting the Fibonacci sequence. Perform necessary error checking to ensure that a non-negative number is passed on the command line.i have done with Fibonacci sequence .but i dont know how to include tht fork() function and win32 api .any one can help to finish?
I am continuously getting fork: resources temporarily unavailable even when I am typing ls command.
View 1 Replies View RelatedI am working on a project where I need to use the C language to generate a tree of processes. I understand how fork() works but I cant seem to get fork() to create two children from one parent and then have the two children create two more children.
Right now what i am seeing is a chain...where the parent creates one child...and that child creates another ONE child..etc.
Here is what I have so far:
for (i=0; i<n;i++){
if (childpid = fork()) break;
}
if (childpid == -1){
perror ("
[Code]....
When a application is ran from the shell:fork() is calledexecve() is calledI know the shell stats the file to make sure the required permissions are allowed in the child shell. But I can not find this in the man fork. Nor can I find this in man execve. Which one of these processes/calls stats the binary to be ran?
View 1 Replies View RelatedI am quite confused about the following description on fork. Could you please explain it ?The child process shall have its own copy of the parent's file descriptors. Each of the child's file descriptors shall refer to the same open file description with the corresponding file descriptor of the parent.For example, I am opening a socket and then fork. Now, does the child have a separate socket or is shares it with the parent. Does I have any impact on using it in child?
View 2 Replies View RelatedI tried the google and browsing the known bugs in the sticky before posting this thread.On boot the machine is pegged at 100%. It is a dual-core with 4GB of ram and is running 10.04, 64bit. Also, as time goes on it eats up all the ram till theres maybe 32mb free. What happens is there are multiple 4-10+ identical processes running. seem to be gnome related.The machine sits idle on my floor and runs samba and apache/mysql/gallery for my test website that no on but myself visits.
View 5 Replies View RelatedI recently inherited a server that I'm now looking after, and when browsing the running processes I came across a number of processes labelled:"/usr/local/apache-2.2.6/bin/.libs/lt-httpd -k start"
At any one time there are between 10 and 15 of them running.Googling the issue has been surprisingly unhelpful... can anybody even tell me what this process is, much less what sort of issue might result in multiple running copies? I'm running Debian Etch (release 4.0).
I have created a simple download schedular with source-code give below :
---------------------record_strokes.sh-------------------
touch /home/student/packs/lynx/logfile
lynx -cmd_log /home/student/packs/lynx/logfile
[code]....
So, this is a simple download scheduler program code. Which creates multiple threads of the downloading process - wget (i could also have used 'curl' instead 'wget').Can you debug this code?
I'm porting C++ application from ARM to MIPS platform. It works now, but I see some strange timing problems. I've seen now that My app process is called multiply time. Here is "top" output:
Mem: 24592K used, 102084K free, 0K shrd, 0K buff, 16864K cached
CPU: 0% usr 99% sys 0% nice 0% idle 0% io 0% irq 0% softirq
Load average: 4.02 2.17 0.95
PID PPID USER STAT VSZ %MEM %CPU COMMAND
1888 1875 admin R 12096 10% 98% ./my_app.exe
code....
I don't see something like this when I compile it for x86, nor ARM.On MIPS I use uClibc instead of glibc.
I scanned hundreds of pages in gray scale and would like to batch process them to B&W. You can do this using the gimp GUI. what it does is get rid of all the gray shading from reflections off the paper when scanned. So you get crisp white backgrounds with black text and diagrams. I would like to simply do this to the entire group directory at one time as it would be quite a lot of effort to open them and do them one by one.
View 3 Replies View Relatedone tell me the internal working of kill command. that is how it kills a process internally or from where it picks file to continue its process.
View 3 Replies View RelatedI have a high priority service that I start with sudo nice -n -10 process. This process does not need superuser rights though, except for the priority elevation. But nice requires superuser privileges to elevate priority.
View 3 Replies View Relatedsend the details raid configuration how to use in linux el5 and how to indentify the raid degrade process and how to rebuilt the process.
View 4 Replies View RelatedCode:
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
[code]....
Description of what the code does or what i intended to do:
1. Created a child process from parent process using 'fork()'
2. Sent a signal 'SIGALRM' from child process to parent process using 'sigqueue' function.
(The Third parameter of 'siqueue' function contains the message (message msg) which the child process wants to send to the parent process.'msg' is a stucture instance containing a) pid of child and b) string) 5. Print the 'msg' sent by child process inside the signal handler function 'sig_action_function' of the parent process I am getting some junk value when this line is executed
Code:
printf("%d
",msg->cpid);
I expected to get the pid of child process, which the child process sent to parent process through the signal.