Process Control Block

The Process Control Block

Every process in Linux is represented by a Process Control Block (PCB) — a struct that holds everything the kernel needs to know about a process. In the Linux source, this is called task_struct and lives in include/linux/sched.h.

A minimal PCB contains:

#define NEW     0
#define READY   1
#define RUNNING 2
#define WAITING 3
#define ZOMBIE  4

typedef struct {
    int  pid;
    int  state;
    char name[32];
    int  priority;
} PCB;

• pid — process ID, unique identifier assigned by the kernel
• state — current lifecycle state of the process
• name — human-readable name (in Linux: comm, 16 bytes max)
• priority — scheduling priority (0 = highest in Linux's real-time range)

Your Implementation

Write void print_pcb(PCB *p) that prints each field on its own line:

PID:      1
Name:     init
State:    RUNNING
Priority: 0

Use a helper const char *state_name(int s) that maps the state integer to its string.

Your Task

Implement print_pcb that prints the PCB fields in the format shown above.