[PATCH 0/1] MR4023: server: Add cross-platform get_path_from_fd function.

[Marc-Aurel Zent (＠marzent)]

This allows *BSD systems that support kqueue (including macOS) to have working file change notifications when configuring wine `--with-inotify` and linking against https://github.com/libinotify-kqueue/libinotify-kqueue

[PATCH 1/1] server: Add cross-platform get_path_from_fd function.

[Marc-Aurel Zent]

From: Marc-Aurel Zent

---
 server/change.c | 36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

diff --git a/server/change.c b/server/change.c
index 7a806abc017..584df1a0233 100644
--- a/server/change.c
+++ b/server/change.c
@@ -721,6 +721,18 @@ static unsigned int filter_from_inode( struct inode *inode, int is_parent )
     return filter;
 }

+static int get_path_from_fd( int fd, char *path )
+{
+#if defined(__APPLE__) || defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
+    return fcntl( fd, F_GETPATH, path );
+#elif defined(linux)
+    sprintf( path, "/proc/self/fd/%u", fd );
+    return 0;
+#else
+    return -1;
+#endif
+}
+
 static char *inode_get_path( struct inode *inode, int sz )
 {
     struct list *head;
@@ -734,9 +746,15 @@ static char *inode_get_path( struct inode *inode, int sz )
     if (head)
     {
         int unix_fd = get_unix_fd( LIST_ENTRY( head, struct dir, in_entry )->fd );
-        path = malloc ( 32 + sz );
+        path = malloc ( PATH_MAX );
         if (path)
-            sprintf( path, "/proc/self/fd/%u/", unix_fd );
+        {
+            if (get_path_from_fd( unix_fd, path ))
+            {
+                free( path );
+                return NULL;
+            }
+        }
         return path;
     }

@@ -964,7 +982,7 @@ static int inotify_adjust_changes( struct dir *dir )
     unsigned int filter;
     struct inode *inode;
     struct stat st;
-    char path[32];
+    char path[PATH_MAX];
     int wd, unix_fd;

if (!inotify_fd)
@@ -990,7 +1008,8 @@ static int inotify_adjust_changes( struct dir *dir )

filter = filter_from_inode( inode, 0 );

-    sprintf( path, "/proc/self/fd/%u", unix_fd );
+    if (get_path_from_fd( unix_fd, path ))
+        return 0;
     wd = inotify_add_dir( path, filter );
     if (wd == -1) return 0;

@@ -1042,7 +1061,7 @@ static int dir_add_to_existing_notify( struct dir *dir )
     struct inode *inode, *parent;
     unsigned int filter = 0;
     struct stat st, st_new;
-    char link[35], *name;
+    char link[PATH_MAX], *name;
     int wd, unix_fd;

if (!inotify_fd)
@@ -1058,7 +1077,9 @@ static int dir_add_to_existing_notify( struct dir *dir )
         return 0;

/* lookup the parent */
-    sprintf( link, "/proc/self/fd/%u/..", unix_fd );
+    if (get_path_from_fd( unix_fd, link ))
+        return 0;
+    strcat( link, "/.." );
     if (-1 == stat( link, &st ))
         return 0;

@@ -1079,7 +1100,8 @@ static int dir_add_to_existing_notify( struct dir *dir )
     if (!filter)
         return 0;

-    sprintf( link, "/proc/self/fd/%u", unix_fd );
+    if (get_path_from_fd( unix_fd, link ))
+        return 0;
     name = get_basename( link );
     if (!name)
         return 0;

[Alexandre Julliard (＠julliard)]

The buffer size needs to be platform-specific as well, we don't want to use PATH_MAX if not necessary. Also you still have to allocate extra space when appending to the buffer.