[Qemu-devel] [PATCH v3 1/4] hw/nvram/fw_cfg: Add fw_cfg_add_file_from_host()

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

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 <philmd@redhat.com>
---
v2: s/ptr/data, corrected documentation (Laszlo)
v3: inverted the if() logic
---
 hw/nvram/fw_cfg.c         | 21 +++++++++++++++++++++
 include/hw/nvram/fw_cfg.h | 23 +++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 7fdf04adc9..2a345bfd5c 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -826,6 +826,27 @@ void fw_cfg_add_file(FWCfgState *s,  const char *filename,
     fw_cfg_add_file_callback(s, filename, NULL, NULL, NULL, data, len, true);
 }
 
+void *fw_cfg_add_file_from_host(FWCfgState *s, const char *filename,
+                                const char *host_path, size_t *len)
+{
+    GError *gerr = NULL;
+    gchar *data = NULL;
+    gsize contents_len = 0;
+
+    if (!g_file_get_contents(host_path, &data, &contents_len, &gerr)) {
+        error_report("%s", gerr->message);
+        g_error_free(gerr);
+        return NULL;
+    }
+    fw_cfg_add_file(s, filename, data, contents_len);
+
+    if (len) {
+        *len = contents_len;
+    }
+
+    return data;
+}
+
 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..7c4dbe2a2a 100644
--- a/include/hw/nvram/fw_cfg.h
+++ b/include/hw/nvram/fw_cfg.h
@@ -166,6 +166,29 @@ 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)
+ *
+ * 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: pointer to the newly allocated file content, or NULL if an error
+ * occured. The returned pointer must be freed with g_free().
+ */
+void *fw_cfg_add_file_from_host(FWCfgState *s, const char *filename,
+                                const char *host_path, size_t *len);
+
 /**
  * fw_cfg_add_file_callback:
  * @s: fw_cfg device being modified
-- 
2.20.1