From 02fbb7a8ea54d1188b2a8410ecd64ae93ac0210e Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Fri, 13 Jan 2023 15:52:17 +0100
Subject: Added process functions

---
 process.cpp | 112 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)

(limited to 'process.cpp')

diff --git a/process.cpp b/process.cpp
index b30ef3d..67cf1ce 100644
--- a/process.cpp
+++ b/process.cpp
@@ -1,9 +1,16 @@
 #include "process.h"
 
 #include <filesystem>
+#include <fstream>
 #include <string>
+#include <thread>
+
+#include <boost/algorithm/string.hpp>
+
+#include <fmt/core.h>
 
 #include "file.h"
+#include "stringhelper.h"
 
 namespace fs = std::filesystem;
 
@@ -25,3 +32,108 @@ bool Reichwein::Process::is_running(pid_t pid)
 
   return state == "R" || state == "S";
 }
+
+// tcp: tcp or tcp6
+bool Reichwein::Process::tcp_is_pid_listening_on(const std::string& tcp, pid_t pid, int port)
+{
+ std::string filename{fmt::format("/proc/{}/net/{}", pid, tcp)};
+ std::ifstream f{filename, std::ios::in};
+ // e.g.:
+ //   sl  local_address rem_address   st tx_queue rx_queue tr tm->when retrnsmt   uid  timeout inode
+ //    0: 00000000:C799 00000000:0000 0A 00000000:00000000 00:00000000 00000000   107        0 21869 1 00000000335416a4 100 0 0 10 0
+ std::string s;
+ std::getline(f, s); // skip head line
+ while (std::getline(f, s)) {
+  boost::algorithm::trim_left(s);
+
+  size_t pos_space1{s.find(' ')};
+  if (pos_space1 == std::string::npos)
+   throw std::runtime_error("Expected first space in " + filename);
+
+  size_t pos_colon1{s.find(':', pos_space1 + 1)};
+  if (pos_colon1 == std::string::npos)
+   throw std::runtime_error("Expected first colon in " + filename);
+  
+  size_t pos_space2{s.find(' ', pos_colon1 + 1)};
+  if (pos_space2 == std::string::npos)
+   throw std::runtime_error("Expected second space in " + filename);
+
+  std::string port_s{s.substr(pos_colon1 + 1, pos_space2 - (pos_colon1 + 1))};
+  auto current_port{std::stoul(port_s, nullptr, 16)};
+  if (current_port != port)
+   continue;
+
+  // now, we are in a line related to matching local port
+  
+  size_t pos_space3{s.find(' ', pos_space2 + 1)};
+  if (pos_space3 == std::string::npos)
+   throw std::runtime_error("Expected third space in " + filename);
+
+  size_t pos_space4{s.find(' ', pos_space3 + 1)};
+  if (pos_space4 == std::string::npos)
+   throw std::runtime_error("Expected fourth space in " + filename);
+
+  std::string state_s{s.substr(pos_space3 + 1, pos_space4 - (pos_space3 + 1))};
+  if (state_s == "0A") // listening state TCP_LISTEN, from <linux_source>/include/net/tcp_states.h
+   return true;
+ }
+
+ return false; // not found
+}
+
+bool Reichwein::Process::is_pid_listening_on(pid_t pid, int port)
+{
+ return tcp_is_pid_listening_on("tcp", pid, port) || tcp_is_pid_listening_on("tcp6", pid, port);
+}
+
+bool Reichwein::Process::unix_is_pid_listening_on(pid_t pid, const std::string& path)
+{
+ std::string filename{fmt::format("/proc/{}/net/unix", pid)};
+ std::ifstream f{filename, std::ios::in};
+ // e.g.:
+ // Num       RefCount Protocol Flags    Type St Inode Path
+ // 000000009ce259a6: 00000003 00000000 00000000 0001 03 29015
+ // 000000003a686108: 00000003 00000000 00000000 0001 03 27263 /run/user/1000/pulse/native
+ // 000000006d62b584: 00000002 00000000 00010000 0001 01 6126359 @/tmp/dbus-b8l6vAYN
+ std::string s;
+ std::getline(f, s); // skip head line
+ while (std::getline(f, s)) {
+  boost::algorithm::trim_left(s);
+  std::vector<std::string> columns{Reichwein::Stringhelper::split(s, " ")};
+  if (columns.size() < 8)
+   continue;
+
+  std::string current_path = columns[7];
+
+  if (current_path[0] == '@')
+   current_path = current_path.substr(1);
+
+  if (current_path != path)
+   continue;
+
+  std::string state = columns[5];
+
+  // I would expect "0A" here, since net/unix/af_unix.c also uses
+  // TCP_LISTEN etc. as in TCP sockets /proc/{}/net/tcp.
+  // But practically, I always get "01"
+  if (state == "0A" || state == "01") // listening state TCP_LISTEN, from <linux_source>/include/net/tcp_states.h
+   return true;
+ }
+
+ return false; // not found
+}
+
+void Reichwein::Process::wait_for_pid_listening_on(pid_t pid, int port)
+{
+ while (!is_pid_listening_on(pid, port)) {
+  std::this_thread::sleep_for(std::chrono::milliseconds(10));
+ }
+}
+
+void Reichwein::Process::wait_for_pid_listening_on(pid_t pid, const std::string& path)
+{
+ while (!unix_is_pid_listening_on(pid, path)) {
+  std::this_thread::sleep_for(std::chrono::milliseconds(10));
+ }
+}
+
-- 
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