From 26248772325231d2a1d0b8bf81083228836378ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Yves=20R=C5=B1tschl=C3=A9?= <git1@rutschle.net>
Date: Tue, 12 Aug 2025 23:05:24 +0200
Subject: [PATCH] sslh-ev: keep track of forked processes

---
 hash.c         |  3 ++-
 processes.c    | 39 +++++++++++++++++++++------------------
 processes.h    |  3 ++-
 sslh-ev.c      | 20 ++++++++++++++++++++
 sslh-select.c  | 23 +++++++++++++++++++++++
 tcp-listener.c | 13 ++++---------
 tcp-listener.h |  8 --------
 7 files changed, 72 insertions(+), 37 deletions(-)

diff --git a/hash.c b/hash.c
index cd79f2d..5105254 100644
--- a/hash.c
+++ b/hash.c
@@ -46,6 +46,7 @@
 
 #if 0
 #define DEBUG 1
+#include <stdio.h>
 #endif
 
 typedef void* hash_item;
@@ -169,7 +170,7 @@ int hash_insert(hash* h, hash_item new)
         if (distance(index, h, curr_item) < distance(index, h, new)) {
             gap_set(h->data, index, new);
 #if DEBUG
-            fprintf(stderr, "intermediate insert [%d] at %d\n", new->pid, index);
+            fprintf(stderr, "intermediate insert at %d\n", index);
 #endif
             new = curr_item;
         }
diff --git a/processes.c b/processes.c
index 294b114..0f20688 100644
--- a/processes.c
+++ b/processes.c
@@ -26,6 +26,14 @@
 #include "probe.h"
 #include "log.h"
 
+/* Struct to keep track of an association of a forked PID to its
+ * listening socket and its protocol */
+struct pid2proto {
+    pid_t pid;
+    struct listen_endpoint* endpoint;
+    struct sslhcfg_protocols_item* proto;
+};
+
 
 int tidy_connection(struct connection *cnx, struct loop_info* fd_info)
 {
@@ -130,10 +138,7 @@ static int pid_cmp(hash_item item1, hash_item item2)
 
 /* When a child has died, update the counts appropriately */
 void decrease_forked_connection(struct loop_info* loop, pid_t pid) {
-    struct pid2proto p2p = {
-        .pid = pid,
-        .proto = NULL
-    };
+    struct pid2proto p2p = { .pid = pid };
     struct pid2proto* found = hash_find(loop->pid2proto, &p2p);
     dec_proto_connections(found->proto);
     dec_listen_connections(found->endpoint);
@@ -142,20 +147,18 @@ void decrease_forked_connection(struct loop_info* loop, pid_t pid) {
     free(found);
 }
 
-/* Check if SIGCHLD was received, find which PID and reap appropriately */
-extern volatile sig_atomic_t received_sigchld;
-void sigchld_process(struct loop_info* loop)
+
+typedef struct pid2proto* hash_item;
+#include "hash.h"
+void remember_child_data(struct loop_info* fd_info,
+                         struct connection* cnx, pid_t pid)
 {
-    int chld;
-    if (received_sigchld) {
-        received_sigchld = 0;
-        do {
-            chld = waitpid(-1, NULL, WNOHANG);
-            CHECK_RES_RETURN(chld, "waitpid", );
-            if (chld) {
-                decrease_forked_connection(loop, chld);
-            }
-        } while (chld);
+    struct pid2proto* pid2proto = malloc(sizeof(*pid2proto));
+    pid2proto->pid = pid;
+    pid2proto->proto = cnx->proto;
+    pid2proto->endpoint = cnx->endpoint;
+    if (hash_insert(fd_info->pid2proto, pid2proto)) {
+        /* TODO something if it fails */
     }
 }
 
@@ -170,7 +173,7 @@ void loop_init(struct loop_info* loop)
 
     loop->pid2proto = hash_init(32, pid_make_key, pid_cmp);
     if (!loop->pid2proto) {
-        /* do something!  (we're also not doing anything for UDP) */
+        /* TODO do something!  (we're also not doing anything for UDP) */
     }
 }
 
diff --git a/processes.h b/processes.h
index 6c3afae..acc0eaf 100644
--- a/processes.h
+++ b/processes.h
@@ -33,7 +33,8 @@ struct connection* cnx_accept_process(struct loop_info* fd_info, struct listen_e
 int tidy_connection(struct connection *cnx, struct loop_info* fd_info);
 void loop_init(struct loop_info* loop);
 
-void sigchld_process(struct loop_info* loop);
+void remember_child_data(struct loop_info* fd_info, 
+                         struct connection* cnx, pid_t pid);
 
 /* These must be declared in the loop handler, sslh-ev or sslh-select */
 void watchers_add_read(watchers* w, int fd);
diff --git a/sslh-ev.c b/sslh-ev.c
index 3e2a4b9..321d5d0 100644
--- a/sslh-ev.c
+++ b/sslh-ev.c
@@ -129,6 +129,26 @@ static void cnx_accept_cb(EV_P_ ev_io *w, int revents)
     cnx_accept_process(info, gap_get(info->watchers->fd2ls, w->fd));
 }
 
+
+void sigchld_cb(EV_P_ ev_child *w, int revents)
+{
+    printf("sigchld_cb %d\n", w->pid);
+    struct loop_info* info = ev_userdata(EV_A);
+    ev_child_stop(EV_A_ w);
+
+    decrease_forked_connection(info, w->pid);
+    free(w);
+}
+
+void watcher_sigchld(struct loop_info* fd_info, struct connection* cnx, pid_t pid)
+{
+    ev_child* cw = malloc(sizeof(*cw));
+
+    ev_child_init(cw, sigchld_cb, pid, 0);
+    ev_child_start(EV_DEFAULT_ cw);
+}
+
+
 void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
 {
     struct loop_info ev_info;
diff --git a/sslh-select.c b/sslh-select.c
index 8516779..e5e82fc 100644
--- a/sslh-select.c
+++ b/sslh-select.c
@@ -88,8 +88,31 @@ void watchers_del_write(watchers* w, int fd)
     FD_CLR(fd, &w->fds_w);
 }
 
+void watcher_sigchld(struct loop_info* fd_info, struct connection* cnx, pid_t pid)
+{
+    /* Nothing to do, watcher is processed in the event loop when select() is
+     * interrupted by the signal */
+}
+
 /* /end watchers */
 
+/* Check if SIGCHLD was received, find which PID and reap appropriately */
+extern volatile sig_atomic_t received_sigchld;
+static void sigchld_process(struct loop_info* loop)
+{
+    int chld;
+    printf("sigchld_process\n");
+    if (received_sigchld) {
+        received_sigchld = 0;
+        do {
+            chld = waitpid(-1, NULL, WNOHANG);
+            CHECK_RES_RETURN(chld, "waitpid", );
+            if (chld) {
+                decrease_forked_connection(loop, chld);
+            }
+        } while (chld);
+    }
+}
 
 
 
diff --git a/tcp-listener.c b/tcp-listener.c
index 227e79d..728d426 100644
--- a/tcp-listener.c
+++ b/tcp-listener.c
@@ -26,8 +26,6 @@
 #include "log.h"
 
 
-typedef struct pid2proto* hash_item;
-#include "hash.h"
 
 /* Removes cnx from probing list */
 static void remove_probing_cnx(struct loop_info* fd_info, struct connection* cnx)
@@ -309,15 +307,12 @@ void fork_shoveling_process(struct loop_info* fd_info, struct connection* cnx) {
     case -1: print_message(msg_system_error, "fork failed: err %d: %s\n", errno, strerror(errno));
              break;
     default: /* parent */
-             struct pid2proto* pid2proto = malloc(sizeof(*pid2proto));
-             pid2proto->pid = pid;
-             pid2proto->proto = cnx->proto;
-             if (hash_insert(fd_info->pid2proto, pid2proto)) {
-                 /* TODO something if it fails */
-             }
+             remember_child_data(fd_info, cnx, pid);
+             watcher_sigchld(fd_info, cnx, pid);
              break;
     }
-    /* Free file descriptor, but do not reduce protocol count */
+    /* Free file descriptor (used only in child), but do not reduce connection
+     * counts */
     cnx->proto = NULL;
     cnx->endpoint = NULL;
     tidy_connection(cnx, fd_info);
diff --git a/tcp-listener.h b/tcp-listener.h
index e6f8e53..e67606d 100644
--- a/tcp-listener.h
+++ b/tcp-listener.h
@@ -5,14 +5,6 @@
 #include "collection.h"
 #include "tcp-probe.h"
 
-/* Struct to keep track of an association of a forked PID to its
- * listening socket and its protocol */
-struct pid2proto {
-    pid_t pid;
-    struct listen_endpoint* endpoint;
-    struct sslhcfg_protocols_item* proto;
-};
-
 void tcp_read_process(struct loop_info* fd_info, int fd);
 struct connection* accept_new_connection(struct listen_endpoint* endpoint, struct loop_info* fd_info);
 void probing_read_process(struct connection* cnx, struct loop_info* fd_info);