insert date into cgo files to invalidate cache

README.md

@@ -1,6 +1,7 @@
 # wolfSSL Golang Wrapper
 
-This repository contains a very light wrapper around wolfSSL for GO, a server/client example, and some example wolfCrypt applications.
+This repository contains a very light wrapper around wolfSSL for GO, a
+server/client example, and some example wolfCrypt applications.
 
 ## Usage
 
@@ -19,60 +20,76 @@ If you plan to use the `wolftls` subpackage and need concurrent `Read` and
 `Write` on a single `Conn` to run in parallel, add `--enable-writedup` to the
 `./configure` line above. Otherwise, the calls will be serialized.
 
-Then clone the go-wolfssl repo and run the `./generateOptions.sh` script to customize go-wolfssl to the same feature set as wolfSSL. This script will generate an `options.go` file that will keep go-wolfssl and wolfSSL in sync. `generateOptions` should be run any time you change your wolfSSL configure options. If the path to your wolfSSL directory is `../wolfssl`, just run:
+Then clone the go-wolfssl repo and run the `./generateOptions.sh` script to
+customize go-wolfssl to the same feature set as wolfSSL. This script will
+generate an `options.go` file that will keep go-wolfssl and wolfSSL in sync.
+Ideally, `generateOptions` should be run any time the wolfSSL install is
+modified. At minimum, it should be run whenever the configure changes. If the
+path to your wolfSSL directory is `./wolfssl`, just run:
+
 ```
 git clone https://github.com/wolfSSL/go-wolfssl
 cd go-wolfssl
 ./generateOptions.sh
 ```
 
-If you have a different path to your wolfSSL directory, run the script with the right path:
+If you have a different path to your wolfSSL directory, run the script with
+the right path:
+
 ```
-./generateOptions.sh ../files/wolfSSL
+./generateOptions.sh /path/to/wolfssl
 ```
 
 If wolfSSL is installed (i.e. `make install`'d to a custom `--prefix=...` path),
 pass the install prefix instead:
+
 ```
 ./generateOptions.sh /usr/local        # system install
 ./generateOptions.sh /opt/wolfssl-fips # custom prefix
 ```
 
-Every invocation regenerates `options.go` and rewrites the `#cgo` `CFLAGS` /
-`LDFLAGS` directives in every cgo-bearing file, so the whole tree agrees on one
-wolfSSL. An install prefix points them at that prefix; a source root or no
-argument points them at `/usr/local`.
+Every invocation regenerates `options.go`, writes a new options generation date,
+and rewrites the `#cgo` `CFLAGS` / `LDFLAGS` directives in every cgo-bearing
+file, so the whole tree agrees on one wolfSSL. An install prefix points the
+files at the given prefix. A source root or no argument will point the files
+at `/usr/local`.
 
 The prefix may contain only letters, digits and `/ _ . : + -`, since a `#cgo`
 directive cannot express a path containing spaces or shell metacharacters.
 Anything else is rejected. On any failure the script exits 99 and leaves the
 tree as it found it.
 
 To install the wrapper module, run these commands:
+
 ```
 go get -u github.com/wolfssl/go-wolfssl
-go mod edit -replace github.com/wolfssl/go-wolfssl=<path to your go-wolfssl directory>
+go mod edit -replace github.com/wolfssl/go-wolfssl=</path/to/go-wolfssl>
 ```
 
 ## Running the TLS Server/Client example
 
 The example `.go` files are located in the `client` and `server` directories.
 
 To build the server, run:
+
 ```
 cd examples/server
 go build server.go
 ```
 
 To build the client, run:
+
 ```
 cd examples/client
 go build client.go
 ```
 
-**NOTE**: Make sure to run both the server and client from within their directories or change the certificate and key paths in the code so that the files are found.
+**NOTE**: Make sure to run both the server and client from within their
+directories or change the certificate and key paths in the code so that the
+files are found.
 
-See [examples/README.md](examples/README.md) for details on building/running the other examples.
+See [examples/README.md](examples/README.md) for details on building/running
+the other examples.
 
 ## Support
 

aes.go

@@ -20,6 +20,8 @@
 
 package wolfSSL
 
+// Options generation date:
+
 // #cgo CFLAGS: -g -Wall -I/usr/local/include
 // #cgo LDFLAGS: -L/usr/local/lib -lwolfssl -lm
 // #include <wolfssl/options.h>

examples/client/client-psk.go

@@ -20,6 +20,8 @@
 
 package main
 
+// Options generation date:
+
 // #cgo CFLAGS: -g -Wall -I/usr/local/include
 //#include <string.h>
 //#include <wolfssl/options.h>

examples/server/server-psk.go

@@ -20,6 +20,8 @@
 
 package main
 
+// Options generation date:
+
 // #cgo CFLAGS: -g -Wall -I/usr/local/include
 //#include <string.h>
 //#include <wolfssl/options.h>

generateOptions.sh

@@ -11,6 +11,7 @@
 OPTIONS_H="../wolfssl/wolfssl/options.h"
 DEFAULT_PREFIX="/usr/local"
 PREFIX=""
+DATE="$(date)"
 
 CGO_FILES="aes.go wolftls/conn.go wolfx509/certgen_wolfcrypt.go \
            examples/client/client-psk.go examples/server/server-psk.go"
@@ -90,12 +91,18 @@ esac
 trap on_exit EXIT
 trap 'exit 99' INT TERM
 
+# The 'Options generation date:' lines below are not decorative. These help
+# invalidate the cache generated by go (i.e., when wolfssl is rebuilt with the
+# same configure).
+
 rm -f options.go
-echo "package wolfSSL"                                       >> options.go
-echo ""                                                      >> options.go
-echo "// #cgo CFLAGS: -g -Wall -I$PREFIX/include"            >> options.go
-echo "// #cgo LDFLAGS: -L$PREFIX/lib -lwolfssl -lm"          >> options.go
-sed 's/^/\/\/ /' "$OPTIONS_H"                                >> options.go
+echo "package wolfSSL"                                      >> options.go
+echo ""                                                     >> options.go
+echo "// Options generation date: $DATE"                    >> options.go
+echo ""                                                     >> options.go
+echo "// #cgo CFLAGS: -g -Wall -I$PREFIX/include"           >> options.go
+echo "// #cgo LDFLAGS: -L$PREFIX/lib -lwolfssl -lm"         >> options.go
+sed 's/^/\/\/ /' "$OPTIONS_H"                               >> options.go
 if [ $? -ne 0 ]; then
     echo "Failed to generate options.go from $OPTIONS_H."
     exit 99
@@ -105,6 +112,7 @@ echo "options.go generated from $OPTIONS_H."
 # #cgo directives are package-scoped, so each cgo-using package carries one
 # declaration. Replace the whole directive line to prevent drift.
 sed -i.bak \
+    -e "s|^// Options generation date:.*|// Options generation date: $DATE|" \
     -e "s|^// #cgo CFLAGS:.*|// #cgo CFLAGS: -g -Wall -I$PREFIX/include|" \
     -e "s|^// #cgo LDFLAGS:.*|// #cgo LDFLAGS: -L$PREFIX/lib -lwolfssl -lm|" \
     $CGO_FILES
@@ -113,6 +121,11 @@ if [ $? -ne 0 ]; then
     exit 99
 fi
 
+for f in $CGO_FILES; do
+    grep -q -- 'Options generation date: ' "$f" || \
+        { echo "$f Options generation date not updated"; exit 99; }
+done
+
 SUCCESS=1
 
 echo "cgo paths pointed at $PREFIX."

wolftls/conn.go

@@ -20,6 +20,8 @@
 
 package wolftls
 
+// Options generation date:
+
 // #cgo CFLAGS: -g -Wall -I/usr/local/include
 // #cgo LDFLAGS: -L/usr/local/lib -lwolfssl -lm
 import "C"

wolfx509/certgen_wolfcrypt.go

@@ -20,6 +20,8 @@
 
 package wolfx509
 
+// Options generation date:
+
 // #cgo CFLAGS: -g -Wall -I/usr/local/include
 // #cgo LDFLAGS: -L/usr/local/lib -lwolfssl -lm
 // #include <stdlib.h>