Add pages with notes on uhttpd and building an image.

BuildOpenwrt.md

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+# Building OpenWRT for the WifiBox
+
+TODO: add steps to clone openwrt, install required software, create an image (on OSX) and fetch package feeds
+
+When changing enabled packages, make sure the image has been created (check the timestamp). If not, the contents were probably too large to fit on the device.
+Luci and Python (even mini) are notable for causing this.
+
+## Configuration changes
+- set target system ar7xxx/ar9xxx
+- set target profile to TP-Link MR3020 or WR703N
+- disable all target images except squashfs
+- enable 'Build the OpenWrt SDK' (or just toolchain?) in case you want to include your own packages
+- enable Base System/wireless-tools (Utilities/iwinfo not needed unless cmdline tool is needed)
+- enable Languages/Lua/lua
+- enable Libraries/libuci-lua
+- Languages/Lua/libiwinfo-lua
+- (*ignore this one, it crashes uhttpd*) enable Network/Web Servers&Proxies/uhhtpd-mod-lua and follow this: http://wiki.openwrt.org/doc/uci/uhttpd#embedded.lua
+- disable Network/ppp and Network/ppp/ppp-mod-pppoe
+- (Global build settings) disable kernel symbol table, debug info and sysrq support
+- (Global build settings) disable ipv6
+
+## Extra changes (optional)
+- enable LuCI/Collections/luci if you want it
+- enable LuCI/Themes/luci-theme-bootstrap if you like
+- enable Languages/Python/python-mini if you want Python
+- enable uhttpd debug messages (Network/Web Servers\/Proxies)
+
+## Further notes on setting up an unconfigured device
+- it might be necessary to remove the host key from .ssh/known_hosts to prevent an ssh error
+- it might be handy to add a host entry to `.ssh/config` so you don't need to use an account name and can use a hostname instead of IP
+- set password to have the device switch from telnet to ssh
+- upload `.ssh/id_rsa.pub` to `/etc/dropbear/authorized_keys` for public key authorization
+- change the wired IP to something not very common to avoid collisions (e.g. 192.168.5.1/24)
+- upload files under <<file extra/wifibox-restore-files master>> to the device
+- deploy contents of src directory to /usr/share/lua/autowifi (create the directory first with mkdir -p)
+- check the <<file src/README master>> in the src directory for final setup steps

UhttpdCrash.md

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+# Analyzing uhttpd crashes
+
+TODO: describe when this happens (sometimes in portal mode and always when webroot does not exist?).
+
+- First, enable debug support in the binary by modifying package/network/services/uhttpd/Makefile: add `TARGET_CFLAGS += -ggdb3 -O0` below `TARGET_LDFLAGS`.
+- Next, enable building the toolchain (we need a gdb which understands mips images).
+- Make sure symbol stripping is disabled (under Global build settings) and check that other settings are correct as well (e.g. core dumps and process debugging enabled).
+- After updating with the new firmware, enable core dumps by running `ulimit -c unlimited`.
+- Stop uhttpd (`/etc/init.d/uhttpd stop`).
+- Run it yourself: `uhttpd -f -p 80 -h /www`.
+- Do something to make it crash and voila.
+- After copying the file over to the host computer, open it in gdb with this command: `<gdb-executable> uhttpd <core-file>`.
+  There must be a more logical place, but at least the gdb executable can be found under the `staging_dir/toolchain/<target-spec>/bin` directory.
+  (More likely is `build_dir/target-<spec>/OpenWrt-Toolchain-<spec>/toolchain-<spec>/bin`...add it to the PATH for easier access)
+
+## Some handy gdb commands
+From [here](http://stackoverflow.com/questions/5115613/core-dump-file-analysis).
+
+- bt			(backtrace)
+- frame n		(select stack frame n)
+- info locals	(display variables)
+- list			(display code)
+- print v
+
+## Further notes
+- [posts about uhttpd on openwrt](https://dev.openwrt.org/search?q=uhttpd)