Add support for the utime(2) family of system calls to the sdcard fuse filesystem.

Add support for the utime(2) family of system calls to change the modify
and access time of files.  Requires an updated bionic with support for
the utimensat(2) system call.

Change-Id: I8cc0c0e6671c5708849752f47e4c3d4be2858b61
diff --git a/sdcard/sdcard.c b/sdcard/sdcard.c
index 0b8f656..7112ebf 100644
--- a/sdcard/sdcard.c
+++ b/sdcard/sdcard.c
@@ -581,17 +581,50 @@
         struct fuse_attr_out out;
         char *path, buffer[PATH_BUFFER_SIZE];
         int res = 0;
+        struct timespec times[2];
 
         TRACE("SETATTR fh=%llx id=%llx valid=%x\n",
               req->fh, hdr->nodeid, req->valid);
 
-        /* XXX: incomplete implementation -- truncate only.  chmod/chown
-         * should NEVER be implemented. */
+        /* XXX: incomplete implementation on purpose.   chmod/chown
+         * should NEVER be implemented.*/
 
         path = node_get_path(node, buffer, 0);
         if (req->valid & FATTR_SIZE)
             res = truncate(path, req->size);
+        if (res)
+            goto getout;
 
+        /* Handle changing atime and mtime.  If FATTR_ATIME_and FATTR_ATIME_NOW
+         * are both set, then set it to the current time.  Else, set it to the
+         * time specified in the request.  Same goes for mtime.  Use utimensat(2)
+         * as it allows ATIME and MTIME to be changed independently, and has
+         * nanosecond resolution which fuse also has.
+         */
+        if (req->valid & (FATTR_ATIME | FATTR_MTIME)) {
+            times[0].tv_nsec = UTIME_OMIT;
+            times[1].tv_nsec = UTIME_OMIT;
+            if (req->valid & FATTR_ATIME) {
+                if (req->valid & FATTR_ATIME_NOW) {
+                  times[0].tv_nsec = UTIME_NOW;
+                } else {
+                  times[0].tv_sec = req->atime;
+                  times[0].tv_nsec = req->atimensec;
+                }
+            }
+            if (req->valid & FATTR_MTIME) {
+                if (req->valid & FATTR_MTIME_NOW) {
+                  times[1].tv_nsec = UTIME_NOW;
+                } else {
+                  times[1].tv_sec = req->mtime;
+                  times[1].tv_nsec = req->mtimensec;
+                }
+            }
+            TRACE("Calling utimensat on %s with atime %ld, mtime=%ld\n", path, times[0].tv_sec, times[1].tv_sec);
+            res = utimensat(-1, path, times, 0);
+        }
+
+        getout:
         memset(&out, 0, sizeof(out));
         node_get_attr(node, &out.attr);
         out.attr_valid = 10;