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73 lines
2.0 KiB
Bash
Executable File
73 lines
2.0 KiB
Bash
Executable File
#!/bin/ash
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# This is the very first script invoked by the Linux kernel and is
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# running out of the ram disk. There are no fileysstems mounted.
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# It is important to have a way to invoke a recovery shell in case
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# the boot scripts are messed up, but also important to modify the
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# PCRs if this happens to prevent the TPM disk keys from being revealed.
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# First thing it is vital to mount the /dev and other system directories
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mkdir /proc /sys /dev /tmp /boot /media 2>&- 1>&-
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mount /dev
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mount /proc
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mount /sys
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# Recovery shells will erase anything from here
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mkdir -p /tmp/secret
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# Setup our path
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export PATH=/sbin:/bin
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# Now it is safe to print a banner
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if [ -r /etc/motd ]; then
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cat /etc/motd
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fi
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# Load the date from the hardware clock, setting it in local time
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hwclock -l -s
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# Read the system configuration parameters
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. /etc/functions
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. /etc/config
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# Add our boot devices into the /etc/fstab, if they are defined
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# in the configuration file.
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if [ ! -z "$CONFIG_BOOT_DEV" ]; then
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echo >> /etc/fstab "$CONFIG_BOOT_DEV /boot auto defaults,ro 0 0"
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fi
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if [ ! -z "$CONFIG_USB_BOOT_DEV" ]; then
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echo >> /etc/fstab "$CONFIG_USB_BOOT_DEV /media auto defaults,ro 0 0"
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fi
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if [ ! -x "$CONFIG_BOOTSCRIPT" ]; then
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recovery 'Boot script missing? Entering recovery shell'
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# just in case...
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tpm extend -ix 4 -ic recovery
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exec /bin/ash
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fi
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# If the user has been holding down r, enter a recovery shell
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# otherwise immediately start the configured boot script.
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# We don't print a prompt, since this is a near instant timeout.
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read \
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-t 0.1 \
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-n 1 \
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boot_option
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echo
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if [ "$boot_option" = "r" ]; then
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# Start an interactive shell
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recovery 'User requested recovery shell'
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# just in case...
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tpm extend -ix 4 -ic recovery
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exec /bin/ash
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fi
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echo '***** Normal boot:' $CONFIG_BOOTSCRIPT
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exec "$CONFIG_BOOTSCRIPT"
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# We should never reach here, but just in case...
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recovery 'Boot script failure? Entering recovery shell'
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# belts and suspenders, just in case...
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tpm extend -ix 4 -ic recovery
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exec /bin/ash
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