daemon: Fix regression introduced in f1d1447e.

With Tanu's patch, the server no longer starts when a server is configured.
While this is sensible in most circumstances there is a corner case where
we still want to start.

In a typical X11 login, module-x11-publish will be loaded and will thus
set the PULSE_SERVER X11 property on the root window. This then hits the
check introduced in f1d1447e and exits. If PA had previously crashed
(thus leaving behind it's X11 properties) then this means that we will not
autospawn nor even allow ourselves to be started manually until
pax11publish -r is run to clear out the X11 properties. This is obviously
not desirable.

This patch introduces a more in-depth check of the server. If it looks like
a local unix domain socket, then we do not exit straight away and instead
probe further. This should not pose any problems with e.g. remote SSH
usage as the DBus Machine ID is used in the server string.

diff --git a/src/daemon/main.c b/src/daemon/main.c
index f939313c27ff6f1cae8159292f2f1103fd4831a8..531665602618a64aecd8ea401333ddc21909df23 100644 (file)
--- a/src/daemon/main.c
+++ b/src/daemon/main.c
@@ -90,6 +90,7 @@
 #include <pulsecore/once.h>
 #include <pulsecore/shm.h>
 #include <pulsecore/memtrap.h>
+#include <pulsecore/strlist.h>
 #ifdef HAVE_DBUS
 #include <pulsecore/dbus-shared.h>
 #endif
@@ -673,10 +674,49 @@ int main(int argc, char *argv[]) {
     }
 
     if (conf->cmd == PA_CMD_START && (configured_address = check_configured_address())) {
-        pa_log_notice(_("User-configured server at %s, not autospawning."), configured_address);
+        /* There is an server address in our config, but where did it come from?
+         * By default a standard X11 login will load module-x11-publish which will
+         * inject PULSE_SERVER X11 property. If the PA daemon crashes, we will end
+         * up hitting this code path. So we have to check to see if our configured_address
+         * is the same as the value that would go into this property so that we can
+         * recover (i.e. autospawn) from a crash.
+         */
+        char *ufn;
+        pa_bool_t start_anyway = FALSE;
+
+        if ((ufn = pa_runtime_path(PA_NATIVE_DEFAULT_UNIX_SOCKET))) {
+            char *id;
+
+            if ((id = pa_machine_id())) {
+                pa_strlist *server_list;
+                char formatted_ufn[256];
+
+                pa_snprintf(formatted_ufn, sizeof(formatted_ufn), "{%s}unix:%s", id, ufn);
+                pa_xfree(id);
+
+                if ((server_list = pa_strlist_parse(configured_address))) {
+                    char *u = NULL;
+
+                    /* We only need to check the first server */
+                    server_list = pa_strlist_pop(server_list, &u);
+                    pa_strlist_free(server_list);
+
+                    start_anyway = (u && pa_streq(formatted_ufn, u));
+                    pa_xfree(u);
+                }
+            }
+            pa_xfree(ufn);
+        }
+
+        if (!start_anyway) {
+            pa_log_notice(_("User-configured server at %s, refusing to start/autospawn."), configured_address);
+            pa_xfree(configured_address);
+            retval = 0;
+            goto finish;
+        }
+
+        pa_log_notice(_("User-configured server at %s, which appears to be local. Probing deeper."), configured_address);
         pa_xfree(configured_address);
-        retval = 0;
-        goto finish;
     }
 
     if (conf->system_instance && !conf->disallow_exit)