41 lines
1.8 KiB
C
41 lines
1.8 KiB
C
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/* +-----------------------------------------------+
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| John Breaux - jab0910 - JohnBreaux@my.unt.edu |
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| syscalls.c - CSCE4600 Homework 1 Question 2 |
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+-----------------------------------------------+ */
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#include <sys/wait.h> // wait()
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#include <unistd.h> // fork(), getpid(), getppid(), execl(), exit()
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#include <stdlib.h> // EXIT_SUCCESS
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#include <stdio.h> // printf()
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// tabs are 3 spaces, because I find it more aesthetically pleasing than x=[1-8]|x!=3 spaces
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int main(int argc, char **argv) {
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// First we fork, and assign the child's pid to a variable
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int child = fork();
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// If we have a child, then we're the parent, and must wait for the child to execute
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if (child) {
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// We get our own pid
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int pid = getpid();
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printf("[PARENT]: pid = %d, child = %d\n", pid, child);
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// Wait for the child to exit, and acquire its status
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int status = 0;
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int exited_child = wait(&status);
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printf("[PARENT]: child %d exited with status %d.\n", exited_child, status);
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// exit
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exit(EXIT_SUCCESS);
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}
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// If we have no child, we are the child, and are assigned the task of executing
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else {
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// Get our pid, get parent's pid
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int pid = getpid(), parent_pid = getppid();
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// Print that information
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printf("[CHILD ]: pid = %d, parent_pid = %d\n", pid, parent_pid);
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// Hand control over to ls, with the arguments "-la"
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char *command = "/bin/ls", *argv1 = "-la";
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printf("[CHILD ]: execl(%s, %s, NULL);\n", command, argv1);
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// execl takes the command, the arguments, and a null-pointer terminator argument
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// argv[0] is the path to the command, argv[1] is the first argument
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// personally I prefer execv()/execve() for their relative ease of use
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execl(command, command, argv1, (char*)NULL);
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}
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}
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