From c62f93a168f85ffdee223b4b96584daaaef05e75 Mon Sep 17 00:00:00 2001
From: Gerhard Rieger <gerhard@dest-unreach.org>
Date: Fri, 12 Aug 2022 12:33:32 +0200
Subject: [PATCH] error.c: signal handler messages socket pair is disabled in
 Filan

---
 CHANGES      |  4 ++++
 error.c      | 31 ++++++++++++++++++++++++++-----
 filan_main.c |  1 +
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/CHANGES b/CHANGES
index 31ba206..8b56ae1 100644
--- a/CHANGES
+++ b/CHANGES
@@ -40,6 +40,10 @@ Corrections:
 	ctype(3) functions need there arguments to be unsigned char.
 	Thanks to Taylor R Campbell for sending a patch.
 
+	Filan library uses Socats diag/error message system and therefore had
+	always the signal handler messages socket pair open. This fix avoids
+	this socketpair in standalone Filan.
+
 Porting:
 	OpenSSL, at least 1.1 on Ubuntu, crashed with SIGSEGV under certain
 	conditions: client connection to server with certificate with empty
diff --git a/error.c b/error.c
index c0a829b..2fad6c2 100644
--- a/error.c
+++ b/error.c
@@ -37,6 +37,7 @@ struct diag_opts {
    int exitstatus;	/* pass signal number to error exit */
    bool withhostname;	/* in custom logs add hostname */
    char *hostname;
+   bool signalsafe;
 } ;
 
 
@@ -44,7 +45,7 @@ static void _diag_exit(int status);
 
 
 struct diag_opts diagopts =
-  { NULL, E_ERROR, E_ERROR, 0, NULL, LOG_DAEMON, false, 0 } ;
+  { NULL, E_ERROR, E_ERROR, 0, NULL, LOG_DAEMON, false, 0, false, NULL, true } ;
 
 static void msg2(
 #if HAVE_CLOCK_GETTIME
@@ -134,8 +135,10 @@ static int diag_init(void) {
    diaginitialized = 1;
    /* gcc with GNU libc refuses to set this in the initializer */
    diagopts.logfile = stderr;
-   if (diag_sock_pair() < 0) {
-      return -1;
+   if (diagopts.signalsafe) {
+      if (diag_sock_pair() < 0) {
+	 return -1;
+      }
    }
    return 0;
 }
@@ -143,6 +146,16 @@ static int diag_init(void) {
 
 
 void diag_set(char what, const char *arg) {
+   switch (what) {
+   case 'I':
+      if (diagopts.signalsafe) {
+	 if (diag_sock_send >= 0) { Close(diag_sock_send); diag_sock_send = -1; }
+	 if (diag_sock_recv >= 0) { Close(diag_sock_recv); diag_sock_recv = -1; }
+      }
+      diagopts.signalsafe = false;
+      return;
+   }
+
    DIAG_INIT;
    switch (what) {
       const struct wordent *keywd;
@@ -240,7 +253,10 @@ int diag_reserve_fd(int fd) {
 int diag_fork() {
    Close(diag_sock_send);
    Close(diag_sock_recv);
-   return diag_sock_pair();
+   if (diagopts.signalsafe) {
+      return diag_sock_pair();
+   }
+   return 0;
 }
 
 /* Linux and AIX syslog format:
@@ -281,7 +297,7 @@ void msg(int level, const char *format, ...) {
    diag_dgram.level = level;
    diag_dgram.exitcode = diagopts.exitstatus;
    vsnprintf_r(diag_dgram.text, sizeof(diag_dgram.text), format, ap);
-   if (diag_in_handler && !diag_immediate_msg) {
+   if (diagopts.signalsafe && diag_in_handler && !diag_immediate_msg) {
       send(diag_sock_send, &diag_dgram, sizeof(diag_dgram)-TEXTLEN + strlen(diag_dgram.text)+1,
 	   0 	/* for canonical reasons */
 #ifdef MSG_DONTWAIT
@@ -399,6 +415,11 @@ static void _msg(int level, const char *buff, const char *syslp) {
 void diag_flush(void) {
    struct diag_dgram recv_dgram;
    char exitmsg[20];
+
+   if (!diagopts.signalsafe) {
+      return;
+   }
+
    while (recv(diag_sock_recv, &recv_dgram, sizeof(recv_dgram)-1,
 	       0 	/* for canonical reasons */
 #ifdef MSG_DONTWAIT
diff --git a/filan_main.c b/filan_main.c
index d19e7b6..5e8ccca 100644
--- a/filan_main.c
+++ b/filan_main.c
@@ -32,6 +32,7 @@ int main(int argc, const char *argv[]) {
    const char *outfname = NULL;
    unsigned long fildes;
 
+   diag_set('I', false);
    diag_set('p', strchr(argv[0], '/') ? strrchr(argv[0], '/')+1 : argv[0]);
 
    arg1 = argv+1;  --argc;