Add thread_create

Author: theo543

frk.c

@@ -1,36 +1,75 @@
+#define _DEFAULT_SOURCE
+
+#include <stdatomic.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <stdio.h>
 
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <sys/mman.h>
+#include <unistd.h>
 
 #include "frk.h"
 
+struct shared_data {
+    atomic_int total_threads;
+    atomic_int total_processes;
+};
+
 static bool initialized = false;
 static int depth = 0;
+static int thread_nr = 0;
+static struct shared_data *shared_data = NULL;
 
 static void close_graph(void) {
     while(wait(NULL) != -1);
+    if(thread_nr > 0) {
+        printf("    %d [xlabel=\"T: %d\"];\n", getpid(), thread_nr);
+    }
     if(depth == 0) {
+        printf("    label=\"Total threads: %d\\nTotal processes: %d\";\n", shared_data->total_threads, shared_data->total_processes);
         printf("}\n");
     }
+    if(munmap(shared_data, sizeof(struct shared_data)) == -1) {
+        perror("munmap");
+    }
 }
 
-pid_t frk(void) {
-    if(!initialized) {
-        printf("digraph process_tree {\n");
-        printf("    %d [label=\"root\"];\n", getpid());
-        atexit(close_graph);
-        initialized = true;
+static void initialize(void) {
+    if(initialized) {
+        return;
+    }
+    shared_data = mmap(NULL, sizeof(struct shared_data), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+    if(shared_data == MAP_FAILED) {
+        perror("mmap");
+        exit(1);
     }
+    shared_data->total_threads = 0;
+    shared_data->total_processes = 1;
+    printf("digraph process_tree {\n");
+    printf("    %d [label=\"root\"];\n", getpid());
+    atexit(close_graph);
+    initialized = true;
+}
+
+pid_t frk(void) {
+    initialize();
     fflush(stdout);
     pid_t child = fork();
     if(child != 0) {
         printf("    %d -> %d;\n", getpid(), child);
         printf("    %d [label=\"lvl %d\"];\n", child, depth + 1);
     } else {
         depth++;
+        thread_nr = 0;
+        shared_data->total_processes++;
     }
     return child;
 }
+
+void thread_create(void) {
+    initialize();
+    thread_nr++;
+    shared_data->total_threads++;
+}

frk.h

@@ -1,3 +1,4 @@
 #include <sys/types.h>
 
 pid_t frk(void);
+void thread_create(void);