3.9 KiB
process
build kernel with initramfs
initramfs /etc/init runs exec busybox switch_root /v3 /opt/wz_mini/etc/init.d/v3_init.sh
within /opt/wz_mini/etc/init.d/v3_init.sh:
bind replace /etc/init.d/inittab with our own version that has rcS located at /opt/wz_mini/tmp/.storage/rcS
bind replace /etc/profile with out own version with added PATH variables for the shell
mount /tmp and /run
mount /system
bind replace /system/bin/factorycheck, this stock firmware program unmounts the binds that we do later in the file, its a debug program. We don't need it.
bind replace /etc/fstab with our own version which includes /opt/wz_mini/tmp as a tmpfs path
create wz_mini's workplace directory at /opt/wz_mini/tmp
copy the stock /etc/init.d/rcS to the workplace directory
modify the stock rcS, add set -x debug mode, inject the following script /opt/wz_mini/etc/init.d/v3_post.sh to run, and add a section to change PATH and LD_LIBRARY if desired
bind replace /etc/shadow to change the stock password
check to see if the swap archive is present at /opt/wz_mini/swap.gz, if it is, extract it, then mkswap it, and drop the vm cache.
check to see if the /opt/wz_mini/usr/share/terminfo directory is present, if not, extract the terminfo files for console programs
mount /configs to check if the .ssh dir is present, a requirement for the dropbear ssh server
check to see if /opt/wz_mini/run_mmc.sh has debug mode enabled, if it does, skip loading /system/bin/app_init.sh and /media/mmc/wz_mini/run_mmc.sh
run /media/mmc/wz_mini/run_mmc.sh, but delay execution for 30 seconds, enough time for WiFi or wired ethernet/usb to load and connect successfully to the internet
run /linuxrc to kick off the stock boot process
our modified inittab runs from /opt/wz_mini/tmp/.storage/rcS, we have enabled set -x debug info, added /opt/wz_mini/bin and /opt/wz_mini/lib to the system PATH's, and added /opt/wz_mini/etc/init.d/v3_post.sh to run before /system/init/app_init.sh runs.
/opt/wz_mini/etc/init.d/v3_post.sh checks if run_mmc.sh has the RTSP server enabled, and if it does, we copy /system/bin/iCamera to our workplace directory at /opt/wz_mini/tmp/.storage/
bind replace /system/bin/iCamera
our version of iCamera is a script which injects the libcallback.so library as LD_PRELOAD to hook the Audio and Video to the RTSP Server, calling iCamera from it's new home at /opt/wz_mini/tmp/.storage/
we then load the video loopback driver from /opt/wz_mini/lib/modules/v4l2loopback.ko
/system/bin/app_init.sh loads the stock system software
During execution of run_mmc.sh, if DISABLE_FW_UPGRADE is set to false we intercept the stock firmware upgrade process. We run inotifyd at startup, to observe the /tmp/Upgrade directory.
Normally, iCamera downloads the firmware upgrade tar to /tmp/img, renames it to /tmp/Upgrade.tar, then extracts it to /tmp/Upgrade
inotifyd monitors /tmp/Upgrade for the file upgraderun.sh, this is the script responsible for flashing the firmware files to their respective partitions. Once the file appears, inotifyd calls the script /opt/wz_mini/usr/bin/watch_up.sh which will rename the file to upgraderun.old and kill the script if iCamera was fast enough to launch it before we renamed it.
watch_up.sh will then proceed to flash the main partitions directly, instead of doing what the stock script does, which is to flash the images to backup partitions, and then let the bootloader flash the main partitions upon reboot, since this process is currently broken when using the loading the kernel from the micro sd card, which we do.
Once the partitions have been flashed, we reboot the camera, and the FW upgrade is complete.