feat: add basic code to list running processes pids

main.c

@@ -0,0 +1,40 @@
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+
+void list_running_processes(void) {
+  DIR *proc_dir = opendir("/proc");
+  if (!proc_dir) {
+    perror("Failed to open /proc");
+    return;
+  }
+
+  struct dirent *entry;
+  struct stat statbuf;
+  char path[512];
+  char *endptr;
+
+  while ((entry = readdir(proc_dir))) {
+    if (entry->d_name[0] == '.') {
+      continue;
+    }
+
+    strtol(entry->d_name, &endptr, 10);
+    if (*endptr != '\0') {
+      continue;
+    }
+
+    snprintf(path, sizeof(path), "/proc/%s", entry->d_name);
+    if (stat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
+      printf("%s\n", entry->d_name);
+    }
+  }
+
+  closedir(proc_dir);
+}
+
+int main(void) {
+  list_running_processes();
+  return 0;
+}