Line discipline for carriage return + ps/kill kshell commands

src/kapps/kshell.c

@@ -13,6 +13,7 @@
 #include <kernel.h>
 #include <time/date.h>
 #include <mem/kheap.h>
+#include <sched/process.h>
 
 __attribute__((noinline))
 void smash_it()
@@ -23,6 +24,52 @@ void smash_it()
     }
 }
 
+extern struct process* processes_list;
+
+void ps()
+{
+    printf("pid\tname\tstatus\n");
+    struct process* curr = processes_list;
+    while (curr != NULL) {
+        char* status;
+        switch (curr->status) {
+            case READY: status = "READY"; break;
+            case RUNNING: status = "RUNNING"; break;
+            case DEAD: status = "DEAD"; break;
+            default: status = "N/A"; break;
+        }
+        printf("%u\t%s\t%s\n", curr->pid, curr->name, status);
+        if (curr->next != NULL) {
+            curr = curr->next;
+        } else {
+            break;
+        }
+    }
+}
+
+void kill()
+{
+    char input_buf[11] = {0};
+    printf("pid> ");
+    keyboard_getline(input_buf, 10);
+    int pid = atoi(input_buf);
+
+    struct process* curr = processes_list;
+    while (curr != NULL) {
+        if (curr->pid == (size_t)pid) {
+            curr->status = DEAD; // equivalent of SIGKILL (no clean termination like SIGTERM)
+            printf("killed %d\n", pid);
+            break;
+        }
+        if (curr->next != NULL) {
+            curr = curr->next;
+        } else {
+            printf("couldn't find process with PID %d\n", pid);
+            break;
+        }
+    }
+}
+
 /*
  * pedicel_main - Kernel shell main function
  * @arg: argument (optional)
@@ -44,15 +91,17 @@ void pedicel_main(void* arg)
         
         if (strncmp(input_buf, "help", 4) == 0) {
             printf("++ shell builtins ++\r\n\r\n"
-                            "\tclear   - clear the screen\r\n"
-                            "\tpanic   - trigger a test panic\r\n"
-                            "\tsyscall - trigger int 0x80\r\n"
-                            "\tpf      - trigger a page fault\r\n"
-                            "\tnow     - get current date\r\n"
-                            "\tsmash   - smash the stack\r\n"
-                            "\tmem     - get used heap info\r\n"
-                            "\tload    - load an user executable\r\n"
-                            "\tlist    - list initfs.tar contents\r\n");
+                            "\tclear   - clear the screen\n"
+                            "\tpanic   - trigger a test panic\n"
+                            "\tsyscall - trigger int 0x80\n"
+                            "\tpf      - trigger a page fault\n"
+                            "\tnow     - get current date\n"
+                            "\tsmash   - smash the stack\n"
+                            "\tmem     - get used heap info\n"
+                            "\tload    - load an user executable\n"
+                            "\tlist    - list initfs.tar contents\n"
+                            "\tps      - list running processes\n"
+                            "\tkill    - kill a running process by PID\n");
             continue;
         }
 
@@ -107,6 +156,16 @@ void pedicel_main(void* arg)
             continue;
         }
 
+        if (strncmp(input_buf, "ps", 2) == 0) {
+            ps();
+            continue;
+        }
+
+        if (strncmp(input_buf, "kill", 4) == 0) {
+            kill();
+            continue;
+        }
+
         printf("%s: command not found\r\n", input_buf);
     }
 }