[Qemu-devel] [PATCH v4 1/4] hw/nvram/fw_cfg: Add fw_cfg_add_file_from_host()

[Philippe Mathieu-Daudé]

Add a function to read the full content of file on the host, and add
a new 'file' name item to the fw_cfg device.

Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
---
v2: s/ptr/data, corrected documentation (Laszlo)
v3: inverted the if() logic
v4: does not return pointer to alloc'd data (Markus)
---
 hw/nvram/fw_cfg.c         | 23 +++++++++++++++++++++++
 include/hw/nvram/fw_cfg.h | 25 +++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 5c3a46ce6f..a8fb829162 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -825,6 +825,29 @@ void fw_cfg_add_file(FWCfgState *s,  const char *filename,
     fw_cfg_add_file_callback(s, filename, NULL, NULL, NULL, data, len, true);
 }
 
+bool fw_cfg_add_file_from_host(FWCfgState *s, const char *filename,
+                               const char *host_path, size_t *len,
+                               Error **errp)
+{
+    GError *gerr = NULL;
+    gchar *data = NULL;
+    gsize contents_len = 0;
+
+    if (!g_file_get_contents(host_path, &data, &contents_len, &gerr)) {
+        error_setg(errp, "%s", gerr->message);
+        g_error_free(gerr);
+        return false;
+    }
+    fw_cfg_add_file(s, filename, data, contents_len);
+    /* TODO g_free 'data' */
+
+    if (len) {
+        *len = contents_len;
+    }
+
+    return true;
+}
+
 void *fw_cfg_modify_file(FWCfgState *s, const char *filename,
                         void *data, size_t len)
 {
diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h
index f5a6895a74..4c8cdd89bb 100644
--- a/include/hw/nvram/fw_cfg.h
+++ b/include/hw/nvram/fw_cfg.h
@@ -166,6 +166,31 @@ void fw_cfg_add_i64(FWCfgState *s, uint16_t key, uint64_t 
value);
 void fw_cfg_add_file(FWCfgState *s, const char *filename, void *data,
                      size_t len);
 
+/**
+ * fw_cfg_add_file_from_host:
+ * @s: fw_cfg device being modified
+ * @filename: name of new fw_cfg file item
+ * @host_path: path of the host file to read the data from
+ * @len: pointer to hold the length of the host file (optional)
+ * @errp: pointer to a NULL initialized error object
+ *
+ * Read the content of a host file as a raw "blob" then add a new NAMED
+ * fw_cfg item of the file size. If @len is provided, it will contain the
+ * total length read from the host file. The data read from the host
+ * filesystem is owned by the new fw_cfg entry, and is stored into the data
+ * structure of the fw_cfg device.
+ * The next available (unused) selector key starting at FW_CFG_FILE_FIRST
+ * will be used; also, a new entry will be added to the file directory
+ * structure residing at key value FW_CFG_FILE_DIR, containing the item name,
+ * data size, and assigned selector key value.
+ *
+ * Returns true on success, false on failure. In the latter case,
+ * an Error object is returned through @errp.
+ */
+bool fw_cfg_add_file_from_host(FWCfgState *s, const char *filename,
+                               const char *host_path, size_t *len,
+                               Error **errp);
+
 /**
  * fw_cfg_add_file_callback:
  * @s: fw_cfg device being modified
-- 
2.20.1