How To Share The Same Code Segment Between Two Processes Using Mmaps?

Hi guys,

I am looking to write a script where I need to process many sets of transactions.
I want to process the set if $ 1 == "01" field $5 = "W", and $ 1 == "07" field $3 = "YY" otherwise copy set to output.

Example of the input file:

Code:

01 08 77 78  W  9890
02 08 66 68 0 8554
07 08  YY  85 9 7545
01 08 99 87 X 8787
04 09 85 85 4 8758
09 87 88 78 7 6584
10 84 ZZ 99 8 9887

A new set is always starting with $1 == "01".
Script should only process first set because its 5th value is "W" and put "MATCHED" in the end.
and copy the unmatched set "X" as it is to output.

Code:

Example of output file:
 01 08 77 78 W 9890
02 08 66 68 0 8554
07 08 YY 85 9 7545
MATCHED 
 01 08 99 87 X 8787
04 09 85 85 4 8758
09 87 88 78 7 6584
10 84 ZZ 99 8 9887 

and so on..
thanks for your help

I want to know the approximate maximum memory usage by my process. If I start the process using "time -v <myprocess>", I get the output after it terminates. This works fine in RedHat Enterprise Linux, but not in Centos. There does not seem to be an option "-v" for time. Do I miss anything ? What is the equivalent in Centos to know the peak memory usage by a process ?

Hello,

I am troubleshooting something and I got this problem.

If I do "pstree -p"

It shows,

Code:

        ├─soffice.bin(7734)─┬─{soffice.bin}(7735)
        │                   ├─{soffice.bin}(7736)
        │                   ├─{soffice.bin}(7737)
        │                   └─{soffice.bin}(7743)

However, it does NOT show up in "ps -elf"

Code:

ps -elf | grep soffi
0 S whho      7734     1  0  80   0 - 36435 -      11:14 pts/2    00:00:03 /usr/lib/openoffice/program/soffice.bin -splash-pipe=5
0 S whho      7833  7759  0  80   0 -   751 -      11:21 pts/3    00:00:00 grep soffi

I was wondering if 7735, 7736, 7737, 7743 were really processes. Then I checked /proc, I could cd to /proc/7735, /proc/7736, etc, but I could not ls them out.

I looked at the man page of "pstree", it says,

Code:

Child threads  of a process are found under the parent process and are shown with the process name in curly braces, e.g.

           icecast2---13*[{icecast2}]

So, what does all this mean? Does it mean that 7735, 7736, 7737, 7743 are just threads but not processes? If so, why could I cd to /proc/<id> but not see them in "ps -elf".

Would somebody please help me?

Thanks!

whho

Hello,

I am working on a board (sbc6000x with at91sam9261 micro, linux 2.6.24 to be precise) and having some fun making script i wanted to make real application.
The board is coming with a cross compilation toolchain. When trying to make a simple "hello world" executable to print on the terminal there is no problem.
I open my terminal, give the path of the compiler, cd into the folder where my .c file is and then i type :
Code:

arm-linux-gcc -o hello hello.c

Which create my executable "hello" and this one is working. But like i said, this program only played with the terminal.

The board is starting with a script calling another executable which use the lcd display, i have the source of this executable. My idea was to look at what was in the source of this application (lots of folders and files) in order to understand how it was working. I wanted to test the toolchain on the source (with the makefile) to see if i was able to generate an executable from a application with folderS/fileS but when i try to "make" it i have this error.

In my understanding this is an object file but aside from that i don't see why it would not works.

Thank you for your future answers !

i need to complete this exercise but my code has some issues
HERE is the PRoblem:
Create a script that can accept ANY amount of numbers from the command line. Process the numbers one at a time, where numbers greater than 10 print “large”, numbers less than or equal to 10 print “small”
E.g. process 5 10 15 would print
small
small
large

and here is my code so far
if [ $@ -le "10" ]
then
echo "smaller"
else
echo "bigger"
shift
fi
if [ $@ -le "10" ]
then
echo "smaller"
else
echo "bigger"
shift
fi
if [ $@ -le "10" ]
then
echo "smaller"
else
echo "bigger"
shift
fi
if [ $@ -le "10" ]
then
echo "smaller"
else
echo "bigger"
shift
fi

any help would be greatly appreciated

I have a directory w/ a file that I created using:
Code:

fd = open("file", O_CREAT);

The file turned out to be executable. When I did a 'ls -l' on the directory w'/ that file it has a "T" at the end of the permissions where the executable bit would be set for the "other" group.

I'm currently reading Brian Wards book: How Linux Works: What Every Superuser Should Know 2nd edition and I'm confused about step 3 in the context of the other steps:
1. The CPU (the actual hardware) interrupts the current process based on an internal timer, switches into kernel mode, and hands control back to the kernel.

2. The kernel records the current state of the CPU and memory, which will be essential to resuming the process that was just interrupted.

3. The kernel performs any tasks that might have come up during the preceding time slice (such as collecting data from input and output, or I/O, operations).

4. The kernel is now ready to let another process run. The kernel analyzes the list of processes that are ready to run and chooses one.

5. The kernel prepares the memory for this new process, and then prepares the CPU.

6. The kernel tells the CPU how long the time slice for the new process will last.

7. The kernel switches the CPU into user mode and hands control of the CPU to the process.

What does he mean preceding time slice as surely the tasks have been completed during the time slice in steps 1-2?

Hello,

I am new to Linux images (pxe, livecd). I would like to add files to a linux image, like something under etc or var, and have the files be available on the client.
The server I am working on was already configured with a pxe image, and only 2 files are present under the pxe client folder: initrd and vmlinuz. So I am wondering if either of these files contain the dirs /etc, /var, etc..., and how I could add files to them.

To give some background, I have done the same thing in Windows. An image in Windows is typically either boot.img or install.img. You can mount either of these to a folder using the Windows SDK tool imagex.exe /mountrw <img file> 1 <mount point>. From here you can add/remove/modify any files you want. Then commit the changes with imagex.exe /unmount <mountpoint> /commit.

Can someone provide insight to the linux image creation process, which of the files (initrd, vmlinuz/vmlinux, etc...) contain what for the client boot, or something similar to the Windows Image editing process?

I know I'm asking for a range of info, but pointers to any material to help my understanding will be greatly appreciated.

Thanks,
Jon

hi all
i am new to linux system programming.
request u to give idea with examples for linux process creation fork() and exec setsig() setalarm(). how to catch these process id's

Regards
Bala

Hi ,
In my program, for a process A executing operation, there are multiple threads created.
One of the thread A checks whether process is active or not
Second thread B executes a function
One of the periodic thread C calls a callback function that executes an audit after every 30 secs.

In the audit , the function uses g_spawn_commmand_line_sync() function to spawn a child process that executes a command line (shell script).

Since g_spawn_commmand_line_sync() spawns a new child process .
In the error case scenario, the spawned child process got stuck and became zombie process. It did not get killed.Also it acquired sockets which were assigned to a thread B executing operation.

Even though the thread B got terminated ,the child process did not release the sockets that were connected to it.


My question is ,I have to automate this in C program that if it finds spawned process of g_spawn_commmand_line_sync() defunct, the
health check thread B should be able to clean it without klling the main process.

i could not find any spawn function that will help me find the PID of g_spawn_commmand_line_sync() spawned process.

I get the details from ps commands. But how can I find it in a c-program?