David Smart / SWUpdate Featured

Software Update via Ethernet - the mbed application can pull down an updated application binary from a web server and activate that binary. This library works only with the LPC1768, as it relies on the magic-chip boot-loader mechanism.

Dependents:   WattEye X10Svr PUB_SWUpdate

Success!! With this library, a network connection, and a web server hosting a new binary image, you can update the mbed firmware over the air (FOTA) - well, at least via Ethernet so far.

As of March 2015, it has been tested with the following mbed official libraries:

And a custom derivation:

  • HTTPClient v33, v32, which includes a custom HTTPFile.

Part of the update process involves checking the integrity of the downloaded binary file, for both a checksum and the program (file) size. To create this additional information, a small perl script is used (the important part is only 20 lines of code). See the documentation in the header file.

After the new binary is successfully downloaded, the checksum and the size are evaluated and if correct, then the old binary file is removed (this is the only way to cause the new binary to activate).

The mbed can then be automatically reset to activate the new image, or this may be deferred in case there is some other process necessary for an orderly restart.

Details are in the SWUpdate header file, and PUB_SWUpdate is a publicly accessible demonstration program for this library.

Diff: SWUpdate.cpp

Revision:
1:208de08b1a19
Parent:
0:e221363f7942
Child:
3:c69fff55fc60
--- a/SWUpdate.cpp	Mon Apr 21 00:20:05 2014 +0000
+++ b/SWUpdate.cpp	Sat Jun 14 15:59:02 2014 +0000
@@ -1,6 +1,7 @@
 
 // Software Update via Ethernet from forum - 
 // http://mbed.org/forum/mbed/topic/1183/
+//
 #include "mbed.h"
 #include "SWUpdate.h"
 #include "HTTPClient.h"
@@ -24,6 +25,10 @@
 #define INFO(x, ...)
 #endif
 
+static bool PassesIntegrityCheck(const char * fname) {
+    return true;
+}
+
 bool SoftwareUpdate(const char *url, const char * name, Reboot_T reboot) {
     HTTPClient http;
     //http.setTimeout( 15000 ); 
@@ -63,34 +68,43 @@
             HTTPFile latest(fwfn);
             r = http.get(fqurl, &latest);
             if (r == HTTP_OK) {
-                sprintf(fwfn, "/local/%s%d.BIN", name, inst_ver);
-                INFO("  Firmware downloaded, removing old version (%s).", fwfn);
-//                if (remove(fwfn)) {
-                    ERR("  *** Failed to remove old version. ***");
-//                }
-                INFO("Updating stored version number.");
-                fv = fopen(verfn, "w");
-                if (fv) {
-                    int fr = fputs(buf, fv);
-                    if (fr < 0) {
-                        ERR("Failed (%d) to update stored version number.", fr);
-                        fclose( fv );
+                // Check the integrity of the freshly downloaded file,
+                // before swapping out the old version.
+                // ... to appear here ...
+                if (PassesIntegrityCheck(fwfn)) {
+                    sprintf(fwfn, "/local/%s%d.BIN", name, inst_ver);
+                    INFO("  Firmware downloaded, removing old version (%s).", fwfn);
+                    if (remove(fwfn)) {
+                        ERR("  *** Failed to remove old version. ***");
+                    }
+                    INFO("Updating stored version number.");
+                    fv = fopen(verfn, "w");
+                    if (fv) {
+                        int fr = fputs(buf, fv);
+                        if (fr < 0) {
+                            ERR("Failed (%d) to update stored version number.", fr);
+                            fclose( fv );
+                        } else {
+                            fclose( fv );
+                            if (reboot == AUTO_REBOOT) {
+                                WARN("Resetting...\n");
+                                wait_ms(200);
+                                mbed_reset();
+                            }
+                            result = true;
+                        }
                     } else {
-                        fclose( fv );
-                        if (reboot == AUTO_REBOOT) {
-                            WARN("Resetting...\n");
-                            wait_ms(200);
-                            mbed_reset();
-                        }
-                        result = true;
+                        WARN("Failed to update local version info in %s.", verfn);
                     }
+                } else {
+                    WARN("New file {%s} did not pass integrity check.", fwfn);
                 }
             } else {
-                WARN("Couldn't download lastest firmware.\n");
+                WARN("Failed to download lastest firmware.");
             }
         }
     } else {
-        WARN("Couldn't check latest firmware version.\n");
+        WARN("Failed to download online firmware version number.");
     }
     return result;
 }