Added signal handler and self connector to gracefully shutdown

.vscode/settings.json

@@ -1,6 +1,7 @@
 {
     "files.associations": {
         "stdlib.h": "c",
-        "process.h": "c"
+        "process.h": "c",
+        "unistd.h": "c"
     }
 }

src/process.c

@@ -0,0 +1,382 @@
+#include <dirent.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "process.h"
+#include "lxcstat.h"
+#include "parsing.h"
+
+#ifndef PF_KTHREAD
+#define PF_KTHREAD 0x00200000
+#endif
+
+#define skipRange(inclusive, exclusive)                            \
+  for (int i##inclusive = 0; i##inclusive < exclusive - inclusive; \
+       i##inclusive++)                                             \
+    location = strchr(location, ' ') + 1;
+
+int parseStatFile(Process *proc, char *filedata) {
+  char *location = filedata;
+  // (1) pid - %d
+  proc->pid = fast_str2ull(&location);
+  location += 2;
+
+  // (2) comm - %s
+  char *end = strrchr(location, ')');
+  size_t length = end - location;
+  memcpy(proc->label, location, length);
+  proc->label[length] = 0;
+  location = end + 2;
+
+  // (3) State - %c
+  location += 2;
+
+  // (4) ppid - %d
+  proc->ppid = fast_str2ull(&location);
+  location += 1;
+
+  // skip [5 - 9)
+  skipRange(5, 9);
+
+  // (9) flags - %u
+  proc->flags = fast_str2ull(&location);
+  location += 1;
+
+  proc->iskernel = (proc->flags & PF_KTHREAD) ? true : false;
+
+  // skip [10 - 14)
+  skipRange(10, 14);
+
+  // (14) utime - %lu
+  proc->cpuTime = fast_str2ull(&location);
+  location += 1;
+
+  // (15) stime - %lu
+  proc->cpuTime += fast_str2ull(&location);
+  proc->cCpuTime = proc->cpuTime;
+  location += 1;
+
+  // skip 16-19
+  skipRange(16, 20);
+
+  // (20) num_threads - %ld
+  proc->nThreads = fast_str2ull(&location);
+  location += 1;
+
+  return 0;
+}
+
+int parseStatusFile(Process *proc, char *filedata) {
+  proc->tgid = findAndParseField(&filedata, "Tgid");
+  proc->pid = findAndParseField(&filedata, "Pid");
+
+  if (proc->pid != proc->tgid)
+    return -1;  // ignore child threads, as their stats are the same as the
+                // parent
+
+  proc->resident = 1024 * findAndParseField(&filedata, "VmRSS");
+  proc->swap = 1024 * findAndParseField(&filedata, "VmSwap");
+  proc->cMemory = proc->resident;
+  proc->cSwap = proc->swap;
+  return 0;
+}
+
+int parseIOFile(Process *proc, char *filedata) {
+  proc->read = findAndParseField(&filedata, "read_bytes");
+  proc->written = findAndParseField(&filedata, "write_bytes");
+  proc->cRead = proc->read;
+  proc->cWrite = proc->written;
+  return 0;
+}
+
+int resetVisits(Process *head) {
+  Process *current = head;
+  int processCount = 0;
+
+  while (current != NULL) {
+    current->visited = 0;
+    current = current->next;
+    processCount++;
+  }
+
+  return processCount;
+}
+
+
+void linkFamily(Process *head) {
+  int orphans = 1;
+
+  while (orphans) {
+    orphans = 0;
+    Process *current = head;
+    // while on an actual process node, and it has a parent link or doesn't need a parent link (kernel)
+    while (current != NULL && (current->parent != NULL || current->ppid == current->pid)) current = current->next;
+    if (current == NULL) break;
+    orphans = 1;
+    
+    Process *parent = head;
+    while (parent != NULL && parent->pid != current->ppid) parent = parent->next;
+    if (parent == NULL) {
+      printf("Found orphan process: %d\n", current->pid);
+      current->ppid = -1;
+      continue;
+    }
+
+    // We have a parent and a child ready to be united
+    current->parent = parent;
+    Process **placement = &(parent->child);
+    while ((*placement) != NULL) placement = &((*placement)->sibling);
+    *placement = current;
+  }
+}
+
+void printFamilyTree(Process *head) {
+  int processCount = resetVisits(head);
+  int visited = 0;
+  Process *current = head;
+  int depth = 0;
+  
+  while (visited < processCount) {
+    if (current == NULL) {
+      printf("Bad visit count: %d visited of %d processes\n", visited, processCount);
+      break;
+    }
+
+    current->visited = 1;
+    visited++;
+
+    printf("%10d  %10d  %1d  ", current->pid, current->ppid, current->iskernel);
+    // `ps f` style tree
+    for (int i=1; i<depth; i++) printf("    ");
+    if (depth > 0) printf(" \\_ ");
+    printf("%s\n", current->label);
+
+nextProcess:
+    if (current->child != NULL && !current->child->visited) {
+      // process children first
+      depth++;
+      current = current->child; 
+    } else if (current->sibling != NULL) {
+      // process siblings next
+      current = current->sibling;
+    } else if (current->parent != NULL) {
+      // return to parent when tree is exhausted
+      depth--;
+      current = current->parent;
+      goto nextProcess;      // parent was already visited, so find next process from parent
+    } else {
+      // no parent - scan for unvisited process
+      while (current != NULL && current->visited) current = current->next;
+    }
+  }
+}
+
+void aggregateStats(Process *head) {
+  int processCount = resetVisits(head);
+  Process *current = head;
+  int depth = 0;
+  int maxdepth = 0;
+  int visited = 0;
+
+  // assign depth (aka level) of each process
+  while (visited < processCount) {
+    if (current == NULL) {
+      printf("Bad visit count: %d visited of %d processes\n", visited, processCount);
+      break;
+    }
+
+    visited++;
+    current->visited = visited; // store to tag the order the process is visited
+    current->level = depth;
+
+    if (depth > maxdepth) maxdepth = depth;
+
+nextProcess:
+    if (current->child != NULL && !current->child->visited) {
+      // process children first
+      depth++;
+      current = current->child; 
+    } else if (current->sibling != NULL) {
+      // process siblings next
+      current = current->sibling;
+    } else if (current->parent != NULL) {
+      // return to parent when tree is exhausted
+      depth--;
+      current = current->parent;
+      goto nextProcess;      // parent was already visited, so find next process from parent
+    } else {
+      // no parent - scan for unvisited process
+      while (current != NULL && current->visited) current = current->next;
+    }
+  }
+
+  // scan for each depth level, tally stats upwards
+  for (depth=maxdepth; depth>0; depth--) {
+    current = head;
+    while (current != NULL) {
+      while (current != NULL && current->level != depth) current = current->next;
+      if (current == NULL) continue;
+
+      Process *parent = current->parent;
+      parent->cCpuTime += current->cCpuTime;
+      parent->cMemory += current->cMemory;
+      parent->cSwap += current->cSwap;
+      parent->cRead += current->cRead;
+      parent->cWrite += current->cWrite;
+      current = current->next;
+    }
+  }
+}
+
+char *readProcesses(char *procdir) {
+  int len;
+  struct dirent *pDirent;
+  DIR *pDir;
+
+  // Ensure we can open directory.
+
+  pDir = opendir(procdir);
+  if (pDir == NULL) {
+    printf("Cannot open directory '%s'\n", procdir);
+    return NULL;
+  }
+
+  // Process each entry.
+
+  char *buffer = malloc(4096);
+  char *fname = malloc(1024);
+  char first;
+  FILE *file;
+
+  Process *head = calloc(1, sizeof(Process));
+  Process *cur = head;
+  Process *prev = NULL;
+  lxcinfo *lxcs = NULL;
+
+  // First process node is the kernel
+  strcpy(cur->label, "kernel");
+  cur->lxc = -1;
+  cur->visited = 1;
+
+  while ((pDirent = readdir(pDir)) != NULL) {
+    first = pDirent->d_name[0];
+    if (first < '0' || first > '9') continue;
+
+    if (cur->visited) {
+      // get new process if necessary
+      prev = cur;
+      cur->next = calloc(1, sizeof(Process));
+      cur = cur->next;
+    }
+
+    sprintf(fname, "/proc/%s/status", pDirent->d_name);
+    file = fopen(fname, "rb");
+    if (file == NULL) continue;
+    fread(buffer, 1, 4096, file);
+    fclose(file);
+
+    if (parseStatusFile(cur, buffer)) continue;
+
+    // truncate 'status' to 'stat'
+    len = strlen(fname);
+    fname[len - 2] = 0;
+    file = fopen(fname, "rb");
+    if (file == NULL) continue;
+    fread(buffer, 1, 4096, file);
+    fclose(file);
+
+    if (parseStatFile(cur, buffer)) continue;
+
+    sprintf(fname, "/proc/%s/io", pDirent->d_name);
+    file = fopen(fname, "rb");
+    if (file == NULL) continue;
+    fread(buffer, 1, 4096, file);
+    fclose(file);
+
+    if (parseIOFile(cur, buffer)) continue;
+
+    sprintf(fname, "/proc/%s/cpuset", pDirent->d_name);
+    file = fopen(fname, "rb");
+    if (file == NULL) goto nextProcess;
+    fread(cur->cpuset, 1, sizeof(cur->cpuset), file);
+    fclose(file);
+
+    strtok(cur->cpuset, "\n\t ");
+    char *lxcTag = "/lxc/";
+    if (memcmp(cur->cpuset, lxcTag, strlen(lxcTag)) == 0) {
+      // Resides in LXC -- read file and tag
+      sscanf(cur->cpuset, "/lxc/%d/ns", &cur->lxc);
+      if (getLXCInfo(&lxcs, cur->lxc) == NULL) 
+        printf("Failed to read LXC config <%d>\n", cur->lxc);
+    } else {
+      cur->lxc = -1;
+    }
+
+nextProcess:
+    cur->visited = 1;
+  }
+
+  if (!cur->visited) {
+    // if there's an unused node, remove it
+    prev->next = NULL;
+    free(cur);
+  }
+  
+  linkFamily(head);
+  aggregateStats(head);
+  // printFamilyTree(head);
+
+  int clocks = sysconf(_SC_CLK_TCK);
+  char *output = malloc(8 * 1024 * 1024);
+  char *ptr = output;
+
+  cur = head;
+  while (cur != NULL) {
+    // create process descriptor
+    sprintf(buffer,
+            "pid=\"%d\",ppid=\"%d\",label=\"%s\",lxc=\"%d\"",
+            cur->pid, cur->ppid, cur->label, cur->lxc);
+    // process specific stats
+    ptr += sprintf(ptr, "process_cpu_time_seconds{%s} %f\n", buffer, (double) cur->cpuTime / clocks);
+    ptr += sprintf(ptr, "process_num_threads{%s} %lu\n", buffer, cur->nThreads);
+    ptr += sprintf(ptr, "process_resident_bytes{%s} %lu\n", buffer, cur->resident);
+    ptr += sprintf(ptr, "process_swap_bytes{%s} %lu\n", buffer, cur->swap);
+    ptr += sprintf(ptr, "process_fileio_bytes_written{%s} %lu\n", buffer, cur->written);
+    ptr += sprintf(ptr, "process_fileio_bytes_read{%s} %lu\n", buffer, cur->read);
+    ptr += sprintf(ptr, "process_is_kernel_process{%s} %d\n", buffer, cur->iskernel);
+    // cumulative fields
+    ptr += sprintf(ptr, "process_cumulative_cpu_time_seconds{%s} %lu\n", buffer, cur->cCpuTime);
+    ptr += sprintf(ptr, "process_cumulative_resident_bytes{%s} %lu\n", buffer, cur->cMemory);
+    ptr += sprintf(ptr, "process_cumulative_swap_bytes{%s} %lu\n", buffer, cur->cSwap);
+    ptr += sprintf(ptr, "process_cumulative_bytes_read{%s} %lu\n", buffer, cur->cRead);
+    ptr += sprintf(ptr, "process_cumulative_bytes_written{%s} %lu\n", buffer, cur->cWrite);
+    // stats used to make flame chart
+    ptr += sprintf(ptr, "process_tree_depth{%s} %d\n", buffer, cur->level);
+    ptr += sprintf(ptr, "process_visit_index{%s} %d\n", buffer, cur->visited);
+    // free and proceed
+    Process *prev = cur;
+    cur = cur->next;
+    free(prev);
+  }
+
+  lxcinfo *lxc = lxcs;
+  while (lxc != NULL) {
+    sprintf(buffer, "lxc=\"%d\",lxcname=\"%s\"", lxc->lxcid, lxc->hostname);
+    ptr += sprintf(ptr, "lxc_cpu_core_count{%s} %u\n", buffer, lxc->cpucount);
+    ptr += sprintf(ptr, "lxc_memory_limit_bytes{%s} %llu\n", buffer, lxc->memlimit);
+    ptr += sprintf(ptr, "lxc_swap_limit_bytes{%s} %llu\n", buffer, lxc->swaplimit);
+    // free and proceed
+    lxcinfo *prev = lxc;
+    lxc = lxc->next;
+    free(prev);
+  }
+
+  closedir(pDir);
+  free(buffer);
+  free(fname);
+  return output;
+}

src/process.h

@@ -35,4 +35,16 @@ typedef struct st_process {
     uint64_t cWrite;
 } Process;
 
+char *readProcesses(char *procdir);
+void aggregateStats(Process *head);
+
+int resetVisits(Process *head);
+void linkFamily(Process *head);
+void printFamilyTree(Process *head);
+int parseStatFile(Process *proc, char *filedata);
+int parseStatusFile(Process *proc, char *filedata);
+int parseIOFile(Process *proc, char *filedata);
+
+
+
 #endif

src/server.c

@@ -1,7 +1,6 @@
 #include <arpa/inet.h>
-#include <dirent.h>
+#include <pthread.h>
-#include <stdbool.h>
+#include <signal.h>
-#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -10,377 +9,37 @@
 
 #include "process.h"
 #include "lxcstat.h"
-#include "parsing.h"
 
-#ifndef PF_KTHREAD
+volatile sig_atomic_t stop_server = 0;
-#define PF_KTHREAD 0x00200000
-#endif
 
-#define skipRange(inclusive, exclusive)                            \
+void handle_signal(int signal) {
-  for (int i##inclusive = 0; i##inclusive < exclusive - inclusive; \
+    stop_server = 1; // Set the flag to stop the server
-       i##inclusive++)                                             \
-    location = strchr(location, ' ') + 1;
-
-int parseStatFile(Process *proc, char *filedata) {
-  char *location = filedata;
-  // (1) pid - %d
-  proc->pid = fast_str2ull(&location);
-  location += 2;
-
-  // (2) comm - %s
-  char *end = strrchr(location, ')');
-  size_t length = end - location;
-  memcpy(proc->label, location, length);
-  proc->label[length] = 0;
-  location = end + 2;
-
-  // (3) State - %c
-  location += 2;
-
-  // (4) ppid - %d
-  proc->ppid = fast_str2ull(&location);
-  location += 1;
-
-  // skip [5 - 9)
-  skipRange(5, 9);
-
-  // (9) flags - %u
-  proc->flags = fast_str2ull(&location);
-  location += 1;
-
-  proc->iskernel = (proc->flags & PF_KTHREAD) ? true : false;
-
-  // skip [10 - 14)
-  skipRange(10, 14);
-
-  // (14) utime - %lu
-  proc->cpuTime = fast_str2ull(&location);
-  location += 1;
-
-  // (15) stime - %lu
-  proc->cpuTime += fast_str2ull(&location);
-  proc->cCpuTime = proc->cpuTime;
-  location += 1;
-
-  // skip 16-19
-  skipRange(16, 20);
-
-  // (20) num_threads - %ld
-  proc->nThreads = fast_str2ull(&location);
-  location += 1;
-
-  return 0;
 }
 
-int parseStatusFile(Process *proc, char *filedata) {
+void *self_connector_thread(void *arg) {
-  proc->tgid = findAndParseField(&filedata, "Tgid");
+  int port = *((int *) arg);
-  proc->pid = findAndParseField(&filedata, "Pid");
 
-  if (proc->pid != proc->tgid)
+  while (!stop_server) {
-    return -1;  // ignore child threads, as their stats are the same as the
+    sleep(3);  // Wait for the stop signal
-                // parent
-
-  proc->resident = 1024 * findAndParseField(&filedata, "VmRSS");
-  proc->swap = 1024 * findAndParseField(&filedata, "VmSwap");
-  proc->cMemory = proc->resident;
-  proc->cSwap = proc->swap;
-  return 0;
   }
 
-int parseIOFile(Process *proc, char *filedata) {
+  // Connect to the server's listening port to unblock accept()
-  proc->read = findAndParseField(&filedata, "read_bytes");
+  int sock_fd = socket(AF_INET, SOCK_STREAM, 0);
-  proc->written = findAndParseField(&filedata, "write_bytes");
+  if (sock_fd < 0) {
-  proc->cRead = proc->read;
+    perror("self-connector socket");
-  proc->cWrite = proc->written;
-  return 0;
-}
-
-int resetVisits(Process *head) {
-  Process *current = head;
-  int processCount = 0;
-
-  while (current != NULL) {
-    current->visited = 0;
-    current = current->next;
-    processCount++;
-  }
-
-  return processCount;
-}
-
-
-void linkFamily(Process *head) {
-  int orphans = 1;
-
-  while (orphans) {
-    orphans = 0;
-    Process *current = head;
-    // while on an actual process node, and it has a parent link or doesn't need a parent link (kernel)
-    while (current != NULL && (current->parent != NULL || current->ppid == current->pid)) current = current->next;
-    if (current == NULL) break;
-    orphans = 1;
-    
-    Process *parent = head;
-    while (parent != NULL && parent->pid != current->ppid) parent = parent->next;
-    if (parent == NULL) {
-      printf("Found orphan process: %d\n", current->pid);
-      current->ppid = -1;
-      continue;
-    }
-
-    // We have a parent and a child ready to be united
-    current->parent = parent;
-    Process **placement = &(parent->child);
-    while ((*placement) != NULL) placement = &((*placement)->sibling);
-    *placement = current;
-  }
-}
-
-void printFamilyTree(Process *head) {
-  int processCount = resetVisits(head);
-  int visited = 0;
-  Process *current = head;
-  int depth = 0;
-  
-  while (visited < processCount) {
-    if (current == NULL) {
-      printf("Bad visit count: %d visited of %d processes\n", visited, processCount);
-      break;
-    }
-
-    current->visited = 1;
-    visited++;
-
-    printf("%10d  %10d  %1d  ", current->pid, current->ppid, current->iskernel);
-    // `ps f` style tree
-    for (int i=1; i<depth; i++) printf("    ");
-    if (depth > 0) printf(" \\_ ");
-    printf("%s\n", current->label);
-
-nextProcess:
-    if (current->child != NULL && !current->child->visited) {
-      // process children first
-      depth++;
-      current = current->child; 
-    } else if (current->sibling != NULL) {
-      // process siblings next
-      current = current->sibling;
-    } else if (current->parent != NULL) {
-      // return to parent when tree is exhausted
-      depth--;
-      current = current->parent;
-      goto nextProcess;      // parent was already visited, so find next process from parent
-    } else {
-      // no parent - scan for unvisited process
-      while (current != NULL && current->visited) current = current->next;
-    }
-  }
-}
-
-void aggregateStats(Process *head) {
-  int processCount = resetVisits(head);
-  Process *current = head;
-  int depth = 0;
-  int maxdepth = 0;
-  int visited = 0;
-
-  // assign depth (aka level) of each process
-  while (visited < processCount) {
-    if (current == NULL) {
-      printf("Bad visit count: %d visited of %d processes\n", visited, processCount);
-      break;
-    }
-
-    visited++;
-    current->visited = visited; // store to tag the order the process is visited
-    current->level = depth;
-
-    if (depth > maxdepth) maxdepth = depth;
-
-nextProcess:
-    if (current->child != NULL && !current->child->visited) {
-      // process children first
-      depth++;
-      current = current->child; 
-    } else if (current->sibling != NULL) {
-      // process siblings next
-      current = current->sibling;
-    } else if (current->parent != NULL) {
-      // return to parent when tree is exhausted
-      depth--;
-      current = current->parent;
-      goto nextProcess;      // parent was already visited, so find next process from parent
-    } else {
-      // no parent - scan for unvisited process
-      while (current != NULL && current->visited) current = current->next;
-    }
-  }
-
-  // scan for each depth level, tally stats upwards
-  for (depth=maxdepth; depth>0; depth--) {
-    current = head;
-    while (current != NULL) {
-      while (current != NULL && current->level != depth) current = current->next;
-      if (current == NULL) continue;
-
-      Process *parent = current->parent;
-      parent->cCpuTime += current->cCpuTime;
-      parent->cMemory += current->cMemory;
-      parent->cSwap += current->cSwap;
-      parent->cRead += current->cRead;
-      parent->cWrite += current->cWrite;
-      current = current->next;
-    }
-  }
-}
-
-char *readProcesses(char *procdir) {
-  int len;
-  struct dirent *pDirent;
-  DIR *pDir;
-
-  // Ensure we can open directory.
-
-  pDir = opendir(procdir);
-  if (pDir == NULL) {
-    printf("Cannot open directory '%s'\n", procdir);
     return NULL;
   }
 
-  // Process each entry.
+  struct sockaddr_in server_address = {
+      .sin_family = AF_INET,
+      .sin_port = htons(port),
+      .sin_addr.s_addr = htonl(INADDR_LOOPBACK),  // Connect to localhost
+  };
 
-  char *buffer = malloc(4096);
+  connect(sock_fd, (struct sockaddr *)&server_address, sizeof(server_address));
-  char *fname = malloc(1024);
+  sleep(1);
-  char first;
+  close(sock_fd);
-  FILE *file;
+  return NULL;
-
-  Process *head = calloc(1, sizeof(Process));
-  Process *cur = head;
-  Process *prev = NULL;
-  lxcinfo *lxcs = NULL;
-
-  // First process node is the kernel
-  strcpy(cur->label, "kernel");
-  cur->lxc = -1;
-  cur->visited = 1;
-
-  while ((pDirent = readdir(pDir)) != NULL) {
-    first = pDirent->d_name[0];
-    if (first < '0' || first > '9') continue;
-
-    if (cur->visited) {
-      // get new process if necessary
-      prev = cur;
-      cur->next = calloc(1, sizeof(Process));
-      cur = cur->next;
-    }
-
-    sprintf(fname, "/proc/%s/status", pDirent->d_name);
-    file = fopen(fname, "rb");
-    if (file == NULL) continue;
-    fread(buffer, 1, 4096, file);
-    fclose(file);
-
-    if (parseStatusFile(cur, buffer)) continue;
-
-    // truncate 'status' to 'stat'
-    len = strlen(fname);
-    fname[len - 2] = 0;
-    file = fopen(fname, "rb");
-    if (file == NULL) continue;
-    fread(buffer, 1, 4096, file);
-    fclose(file);
-
-    if (parseStatFile(cur, buffer)) continue;
-
-    sprintf(fname, "/proc/%s/io", pDirent->d_name);
-    file = fopen(fname, "rb");
-    if (file == NULL) continue;
-    fread(buffer, 1, 4096, file);
-    fclose(file);
-
-    if (parseIOFile(cur, buffer)) continue;
-
-    sprintf(fname, "/proc/%s/cpuset", pDirent->d_name);
-    file = fopen(fname, "rb");
-    if (file == NULL) goto nextProcess;
-    fread(cur->cpuset, 1, sizeof(cur->cpuset), file);
-    fclose(file);
-
-    strtok(cur->cpuset, "\n\t ");
-    char *lxcTag = "/lxc/";
-    if (memcmp(cur->cpuset, lxcTag, strlen(lxcTag)) == 0) {
-      // Resides in LXC -- read file and tag
-      sscanf(cur->cpuset, "/lxc/%d/ns", &cur->lxc);
-      if (getLXCInfo(&lxcs, cur->lxc) == NULL) 
-        printf("Failed to read LXC config <%d>\n", cur->lxc);
-    } else {
-      cur->lxc = -1;
-    }
-
-nextProcess:
-    cur->visited = 1;
-  }
-
-  if (!cur->visited) {
-    // if there's an unused node, remove it
-    prev->next = NULL;
-    free(cur);
-  }
-  
-  linkFamily(head);
-  aggregateStats(head);
-  // printFamilyTree(head);
-
-  int clocks = sysconf(_SC_CLK_TCK);
-  char *output = malloc(8 * 1024 * 1024);
-  char *ptr = output;
-
-  cur = head;
-  while (cur != NULL) {
-    // create process descriptor
-    sprintf(buffer,
-            "pid=\"%d\",ppid=\"%d\",label=\"%s\",lxc=\"%d\"",
-            cur->pid, cur->ppid, cur->label, cur->lxc);
-    // process specific stats
-    ptr += sprintf(ptr, "process_cpu_time_seconds{%s} %f\n", buffer, (double) cur->cpuTime / clocks);
-    ptr += sprintf(ptr, "process_num_threads{%s} %lu\n", buffer, cur->nThreads);
-    ptr += sprintf(ptr, "process_resident_bytes{%s} %lu\n", buffer, cur->resident);
-    ptr += sprintf(ptr, "process_swap_bytes{%s} %lu\n", buffer, cur->swap);
-    ptr += sprintf(ptr, "process_fileio_bytes_written{%s} %lu\n", buffer, cur->written);
-    ptr += sprintf(ptr, "process_fileio_bytes_read{%s} %lu\n", buffer, cur->read);
-    ptr += sprintf(ptr, "process_is_kernel_process{%s} %d\n", buffer, cur->iskernel);
-    // cumulative fields
-    ptr += sprintf(ptr, "process_cumulative_cpu_time_seconds{%s} %lu\n", buffer, cur->cCpuTime);
-    ptr += sprintf(ptr, "process_cumulative_resident_bytes{%s} %lu\n", buffer, cur->cMemory);
-    ptr += sprintf(ptr, "process_cumulative_swap_bytes{%s} %lu\n", buffer, cur->cSwap);
-    ptr += sprintf(ptr, "process_cumulative_bytes_read{%s} %lu\n", buffer, cur->cRead);
-    ptr += sprintf(ptr, "process_cumulative_bytes_written{%s} %lu\n", buffer, cur->cWrite);
-    // stats used to make flame chart
-    ptr += sprintf(ptr, "process_tree_depth{%s} %d\n", buffer, cur->level);
-    ptr += sprintf(ptr, "process_visit_index{%s} %d\n", buffer, cur->visited);
-    // free and proceed
-    Process *prev = cur;
-    cur = cur->next;
-    free(prev);
-  }
-
-  lxcinfo *lxc = lxcs;
-  while (lxc != NULL) {
-    sprintf(buffer, "lxc=\"%d\",lxcname=\"%s\"", lxc->lxcid, lxc->hostname);
-    ptr += sprintf(ptr, "lxc_cpu_core_count{%s} %u\n", buffer, lxc->cpucount);
-    ptr += sprintf(ptr, "lxc_memory_limit_bytes{%s} %llu\n", buffer, lxc->memlimit);
-    ptr += sprintf(ptr, "lxc_swap_limit_bytes{%s} %llu\n", buffer, lxc->swaplimit);
-    // free and proceed
-    lxcinfo *prev = lxc;
-    lxc = lxc->next;
-    free(prev);
-  }
-
-  closedir(pDir);
-  free(buffer);
-  free(fname);
-  return output;
 }
 
 #define BUFFER_SIZE 1024
@@ -427,25 +86,35 @@ void handle_client(int client_socket) {
 closeConnection:
   printf("Closing connection\n");
   // Close the client socket
-  shutdown(client_socket, SHUT_WR);
-  sleep(1);
   close(client_socket);
-
   free(data);
 }
 
 int main(int argc, char *argv[]) {
-  int port = 9101;
-
   if (argc == 1) {
     char *buf = readProcesses("/proc");
-    if (buf == NULL) return 4;
+    if (buf == NULL) return 1;
     printf(buf);
     free(buf);
     return 0;
+  }
 
-  } else {
+  for (int i=0; i<strlen(argv[1]); i++) {
-    port = atoi(argv[1]);
+    if (argv[1][i] < '0' || argv[1][i] > '9') {
+      fprintf(stderr, "Argument '%s' is not a valid port", argv[1]);
+      return 1;
+    }
+  }
+  
+  int port = atoi(argv[1]);
+  // Set up signal handling
+  struct sigaction sa;
+  sa.sa_handler = handle_signal;
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = 0;
+  if (sigaction(SIGINT, &sa, NULL) == -1 || sigaction(SIGTERM, &sa, NULL) == -1) {
+      perror("sigaction");
+      exit(EXIT_FAILURE);
   }
 
   int server_socket, client_socket;
@@ -478,12 +147,19 @@ int main(int argc, char *argv[]) {
     exit(EXIT_FAILURE);
   }
 
-  printf("Server is listening on port %d\n", port);
+  // Start the self-connector thread
+  pthread_t connector_thread;
+  pthread_create(&connector_thread, NULL, self_connector_thread, (void *) &port);
+
+  printf("Server is listening on port %d (PID %d)\n", port, getpid());
 
   // Accept and handle incoming connections
   while (1) {
-    if ((client_socket = accept(server_socket, (struct sockaddr *)&client_addr,
+    client_socket = accept(server_socket, (struct sockaddr *)&client_addr, &addr_len);
-                                &addr_len)) == -1) {
+    printf("Got client connection\n");
+    if (stop_server) break; // stop if we received SIGTERM or SIGINT
+
+    if (client_socket == -1) {
       perror("Accept failed");
       continue;
     }
@@ -492,8 +168,10 @@ int main(int argc, char *argv[]) {
     handle_client(client_socket);
   }
 
-  // Close the server socket (this won't actually be reached in this example)
+  close(client_socket);
   close(server_socket);
 
+  printf("Shutting down\n");
+  pthread_join(connector_thread, NULL);
   return 0;
 }