nshlib/cmd_memdump: support new command: memdump

Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>

nshlib/nsh_fsutils.c

@@ -286,6 +286,65 @@ int nsh_readfile(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
 }
 #endif
 
+/****************************************************************************
+ * Name: nsh_writefile
+ *
+ * Description:
+ *   Dump the contents of a file to the current NSH terminal.
+ *
+ * Input Paratemets:
+ *   vtbl     - session vtbl
+ *   cmd      - NSH command name to use in error reporting
+ *   buffer   - The pointer of writting buffer
+ *   len      - The length of writting buffer
+ *   filepath - The full path to the file to be dumped
+ *
+ * Returned Value:
+ *   Zero (OK) on success; -1 (ERROR) on failure.
+ *
+ ****************************************************************************/
+
+#ifdef NSH_HAVE_WRITEFILE
+int nsh_writefile(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
+                  FAR const char *buffer, size_t len,
+                  FAR const char *filepath)
+{
+  int fd;
+  int ret;
+
+  /* Open the file for reading */
+
+  fd = open(filepath, O_WRONLY);
+  if (fd < 0)
+    {
+#if defined(CONFIG_NSH_PROC_MOUNTPOINT)
+      if (strncmp(filepath, CONFIG_NSH_PROC_MOUNTPOINT,
+                  strlen(CONFIG_NSH_PROC_MOUNTPOINT)) == 0)
+        {
+          nsh_error(vtbl,
+                    "nsh: %s: Could not open %s (is procfs mounted?): %d\n",
+                    cmd, filepath, NSH_ERRNO);
+        }
+      else
+#endif
+        {
+          nsh_error(vtbl, g_fmtcmdfailed, cmd, "open", NSH_ERRNO);
+        }
+
+      return ERROR;
+    }
+
+  ret = write(fd, buffer, len);
+  if (ret < 0)
+    {
+      nsh_error(vtbl, g_fmtcmdfailed, cmd, "write", NSH_ERRNO);
+    }
+
+  close(fd);
+  return ret > 0 ? OK : ERROR;
+}
+#endif
+
 /****************************************************************************
  * Name: nsh_foreach_direntry
  *