[Qemu-devel] [PATCH v3 01/26] chardev: avoid crash if no associated address

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

A socket chardev may not have associated address (when adding client
fd manually for example). But on disconnect, updating socket filename
expects an address and may lead to this crash:

  Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
  0x0000555555d8c70c in SocketAddress_to_str (prefix=0x555556043062 "disconnected:", addr=0x0, is_listen=false, is_telnet=false) at /home/elmarco/src/qq/chardev/char-socket.c:388
  388	    switch (addr->type) {
  (gdb) bt
  #0  0x0000555555d8c70c in SocketAddress_to_str (prefix=0x555556043062 "disconnected:", addr=0x0, is_listen=false, is_telnet=false) at /home/elmarco/src/qq/chardev/char-socket.c:388
  #1  0x0000555555d8c8aa in update_disconnected_filename (s=0x555556b1ed00) at /home/elmarco/src/qq/chardev/char-socket.c:419
  #2  0x0000555555d8c959 in tcp_chr_disconnect (chr=0x555556b1ed00) at /home/elmarco/src/qq/chardev/char-socket.c:438
  #3  0x0000555555d8cba1 in tcp_chr_hup (channel=0x555556b75690, cond=G_IO_HUP, opaque=0x555556b1ed00) at /home/elmarco/src/qq/chardev/char-socket.c:482
  #4  0x0000555555da596e in qio_channel_fd_source_dispatch (source=0x555556bb68b0, callback=0x555555d8cb58 <tcp_chr_hup>, user_data=0x555556b1ed00) at /home/elmarco/src/qq/io/channel-watch.c:84

Replace filename with a generic "disconnected:socket" in this case.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 chardev/char-socket.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index 159e69c3b1..2a33079f8e 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -416,8 +416,12 @@ static void update_disconnected_filename(SocketChardev *s)
     Chardev *chr = CHARDEV(s);
 
     g_free(chr->filename);
-    chr->filename = SocketAddress_to_str("disconnected:", s->addr,
-                                         s->is_listen, s->is_telnet);
+    if (s->addr) {
+        chr->filename = SocketAddress_to_str("disconnected:", s->addr,
+                                             s->is_listen, s->is_telnet);
+    } else {
+        chr->filename = g_strdup("disconnected:socket");
+    }
 }
 
 /* NB may be called even if tcp_chr_connect has not been
-- 
2.18.0.rc1