[PATCH v4 2/4] libxl: add libxl__xs_path_cleanup

[Roger Pau Monne <roger.pau@citrix.com>]

Add a function which behaves like "xenstore-rm -t", and which will be
used to
clean xenstore after unplug since we will be no longer executing
xen-hotplug-cleanup script, that used to do that for us.

Changes since v3:

 * Better error checking and function description.

Changes since v2:

 * Moved the function to libxl_xshelp.c and added the prototype to
   libxl_internal.h.

Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>
---
 tools/libxl/libxl_internal.h |    7 +++++++
 tools/libxl/libxl_xshelp.c   |   30 ++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 0 deletions(-)

diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 9ab76f8..fc2024d 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -494,6 +494,13 @@ _hidden bool libxl__xs_mkdir(libxl__gc *gc, xs_transaction_t t,
 
 _hidden char *libxl__xs_libxl_path(libxl__gc *gc, uint32_t domid);
 
+/*
+ * This is a recursive delete, from top to bottom. What this function does
+ * is remove empty folders that contained the deleted entry.
+ *
+ * It mimics xenstore-rm -t behaviour.
+ */
+_hidden int libxl__xs_path_cleanup(libxl__gc *gc, char *user_path);
 
 /*
  * Event generation functions provided by the libxl event core to the
diff --git a/tools/libxl/libxl_xshelp.c b/tools/libxl/libxl_xshelp.c
index 3ea8d08..7339236 100644
--- a/tools/libxl/libxl_xshelp.c
+++ b/tools/libxl/libxl_xshelp.c
@@ -135,6 +135,36 @@ char *libxl__xs_libxl_path(libxl__gc *gc, uint32_t domid)
     return s;
 }
 
+int libxl__xs_path_cleanup(libxl__gc *gc, char *user_path)
+{
+    unsigned int nb = 0;
+    char *path, *last;
+
+    if (!user_path) {
+        LOGE(ERROR, "null path provided");
+        return ERROR_FAIL;
+    }
+
+    path = libxl__strdup(gc, user_path);
+    xs_rm(CTX->xsh, XBT_NULL, path);
+
+    for (last = strrchr(path, '/'); last != NULL; last = strrchr(path, '/')) {
+        *last = '\0';
+
+        if (!strlen(path)) break;
+
+        if (!libxl__xs_directory(gc, XBT_NULL, path, &nb)) {
+            LOG(DEBUG, "failed to read directory contents of %s", path);
+            return ERROR_FAIL;
+        }
+
+        if (nb == 0) {
+            xs_rm(CTX->xsh, XBT_NULL, path);
+        }
+    }
+    return 0;
+}
+
 /*
  * Local variables:
  * mode: C
-- 
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