fscrypt: Adding additional documentation

This commit moves most of the documentation about contributing to
fscrypt into CONTRIBUTING.md and updates the legal disclaimer.

It also updates the README.md to include all of fscrypt's planned
functionality and dependencies. Finally, the makefile is updated to
include more documentation, versioning support, and a different location
for the output file.

Change-Id: Ib7be98d41bc06dd12b02e42addf06e12a940235a

1 files changed, 29 insertions, 11 deletions

diff --git a/Makefile b/Makefile
index ac41537..22da24a 100644
--- a/Makefile
+++ b/Makefile
@@ -16,18 +16,36 @@
 # the License.
 
 NAME = fscrypt
-BUILD_DIR = build
-CFLAGS += -O2 -Wall
+# VERSION is formatted as <major>.<minor>.<bugfix>
+# Bugfix releases resolve issues in existing features.
+# Minor releases introduce new features.
+# Major releases may introduce breaking changes to the API.
+VERSION = 0.1.0
+# Holds a formatted string of the build time
+BUILD_TIME = $(shell date)
 
+CFLAGS += -O2 -Wall
 CMD_DIR = $(NAME)/cmd/$(NAME)
 
-# So we don't have to put our flags in each go file. This also lets the caller
-# of the makefile change the build flags in the normal manner:
+# The code below lets the caller of the makefile change the build flags for
+# fscrypt in a familiar manner. For example, to force the program to statically
+# link its C components, run "make fscrypt" with:
 #	make fscrypt "LDFLAGS += -static"
+#
+# Similarly, to modify the flags passed to the C components, just modify CFLAGS
+# or LDFLAGS as you would with a C program. To modify the Go flags, either
+# modify GO_FLAGS or GO_LINK_FLAGS (as appropriate).
+
+# Set the C flags so we don't need to set C flags in each CGO file.
 export CGO_CFLAGS = $(CFLAGS)
-ifdef LDFLAGS
-	GOFLAGS += --ldflags '-extldflags "$(LDFLAGS)"'
-endif
+
+# Pass the version to the command line program
+VERSION_FLAG = -X "main.version=$(VERSION)"
+# Pass the current date and time to the command line program
+DATE_FLAG = -X "main.buildTime=$(BUILD_TIME)"
+# Pass the C linking flags into Go
+GO_LINK_FLAGS += -s -w $(VERSION_FLAG) $(DATE_FLAG) -extldflags "$(LDFLAGS)"
+GOFLAGS += --ldflags '$(GO_LINK_FLAGS)'
 
 .PHONY: default all $(NAME) go update lint format install clean
 
@@ -35,12 +53,11 @@ default: $(NAME)
 all: update go format lint $(NAME)
 
 $(NAME):
-	@mkdir -p $(BUILD_DIR)
-	go build $(GOFLAGS) -o $(BUILD_DIR)/$(NAME) $(CMD_DIR)
+	go build $(GOFLAGS) -o $(NAME) $(CMD_DIR)
 
 # Makes sure go files build and tests pass
 go:
-	govendor generate $(GOFLAGS) +local
+	govendor generate +local
 	govendor build $(GOFLAGS) +local
 	govendor test $(GOFLAGS) +local
 
@@ -55,9 +72,10 @@ lint:
 
 format:
 	@govendor fmt +local
+	@find . -name "*.h" -o -name "*.c" -not -path "./vendor/*" | xargs clang-format -i -style=Google
 
 install:
 	govendor install $(GOFLAGS) +local
 
 clean:
-	rm -rf $(BUILD_DIR)
+	rm -rf $(NAME)