core-util: Attempt to make runtime paths smaller to avoid 108 char limit.

When the runtime path gets long (which can happen on some NFS
mounts where $HOME is not just /home/$USER), it can grow
longer the 108 char limit imposed by sockaddr_un.sun_path.

This just calls realpath which should ultimately point into
/tmp in most cases and result in a much smaller path.

Only do this when we are adding on a name component to the
runtime path so creating the actual symlink will still get
the original, long name, but this shouldn't be a problem
as it never goes into the sockaddr_un.sun_path.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=44680

1 files changed, 16 insertions, 5 deletions

diff --git a/src/pulsecore/core-util.c b/src/pulsecore/core-util.c
index 1aa5a9a6..61f980e7 100644
--- a/src/pulsecore/core-util.c
+++ b/src/pulsecore/core-util.c
@@ -1980,7 +1980,7 @@ static char *get_path(const char *fn, pa_bool_t prependmid, pa_bool_t rt) {
     rtp = rt ? pa_get_runtime_dir() : pa_get_state_dir();
 
     if (fn) {
-        char *r;
+        char *r, *canonical_rtp;
 
         if (pa_is_path_absolute(fn)) {
             pa_xfree(rtp);
@@ -1990,20 +1990,31 @@ static char *get_path(const char *fn, pa_bool_t prependmid, pa_bool_t rt) {
         if (!rtp)
             return NULL;
 
+        /* Hopefully make the path smaller to avoid 108 char limit (fdo#44680) */
+        if ((canonical_rtp = pa_realpath(rtp))) {
+            if (strlen(rtp) >= strlen(canonical_rtp))
+                pa_xfree(rtp);
+            else {
+                pa_xfree(canonical_rtp);
+                canonical_rtp = rtp;
+            }
+        } else
+            canonical_rtp = rtp;
+
         if (prependmid) {
             char *mid;
 
             if (!(mid = pa_machine_id())) {
-                pa_xfree(rtp);
+                pa_xfree(canonical_rtp);
                 return NULL;
             }
 
-            r = pa_sprintf_malloc("%s" PA_PATH_SEP "%s-%s", rtp, mid, fn);
+            r = pa_sprintf_malloc("%s" PA_PATH_SEP "%s-%s", canonical_rtp, mid, fn);
             pa_xfree(mid);
         } else
-            r = pa_sprintf_malloc("%s" PA_PATH_SEP "%s", rtp, fn);
+            r = pa_sprintf_malloc("%s" PA_PATH_SEP "%s", canonical_rtp, fn);
 
-        pa_xfree(rtp);
+        pa_xfree(canonical_rtp);
         return r;
     } else
         return rtp;