CODEWITHSUNDEEP
cunix
user1434883
user1434883

Reputation: 9

Finding pid of background process from c prog

I am writing a program for creating a shell which handles basic functionalities such as executing basic commands,piping,redirection,executing background process.However i am not being able to kill a background process, i need to know the pid() of the background process so that i can send a kill call along with the pid.Any idea how to get the pid() of a background process from a c pogram? For running the commands I am taking input from commandline into an array,parsing it and putting the command in arr[0] and the subsequent arguments in the subsequent indexes,i am taking the PATH of the system into another array and storing them as strings by using strtok and delim option as :,after this i am concatenating the path with the command,and then doing an execv().

I am stuck with this part where i have to kill a background process.Any suggestion would be extremely helpful.

Thanks in advance.

Upvotes: 0

Views: 443

Answers (3)

fhtuft
fhtuft

Reputation: 976

You can call getpid() (in the childprosses), or the pid of the child is returned to the parent when calling fork()

Upvotes: 0

yasar
yasar

Reputation: 13728

You should do something like this:

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

int main()
{
    pid_t pID = fork();
    if (pID == 0) {
        execl("/bin/ls", "/bin/ls", "-r", "-t", "-l", (char *) 0);
    } else {
        waitpid(pID, NULL, 0); // wait for child process
    }
}

Upvotes: 1

aztaroth
aztaroth

Reputation: 989

fork returns the PID of the child in the parent process, store it someplace and then use it to kill?

Upvotes: 1

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