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koreader/platform/kobo/obtain-ip.sh
NiLuJe 9fd6c82b3b
Kobo: Overengineer the manual CLOEXEC logic in the Wi-Fi scripts (#12045)
So it catches non-CLOEXEC sockets properly...

Fix #12043
2024-06-18 21:20:14 +02:00

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#!/bin/sh
# NOTE: Close any non-standard fds, so that it doesn't come back to bite us in the ass with USBMS (or sockets) later...
for fd in /proc/"$$"/fd/*; do
close_me="false"
fd_id="$(basename "${fd}")"
fd_path="$(readlink -f "${fd}")"
if [ -e "${fd}" ] && [ "${fd_id}" -gt 2 ]; then
if [ -S "${fd}" ]; then
# Close any and all sockets
# NOTE: Old busybox builds do something stupid when attempting to canonicalize pipes/sockets...
# (i.e., they'll spit out ${fd} as-is, losing any and all mention of a socket/pipe).
fd_path="$(readlink "${fd}")"
close_me="true"
elif [ -p "${fd}" ]; then
# We *might* be catching temporary pipes created by this very test, se we have to leave pipes alone...
# Although it would take extremely unlucky timing, as by the time we go through the top-level -e test,
# said temporary pipe is already gone, and as such we *should* never really enter this branch for temporary pipes ;).
fd_path="$(readlink "${fd}")"
close_me="false"
else
# NOTE: dash (meaning, in turn, busybox's ash) uses fd 10+ open to /dev/tty or $0 (w/ CLOEXEC)
# NOTE: The last fd != fd_path check is there to (potentially) whitelist non-regular files we might have failed to handle,
# it's designed to match the unhelpful result from old buysbox's readlink -f on non-regular files (c.f., previous notes).
if [ "${fd_path}" != "/dev/tty" ] && [ "${fd_path}" != "$(readlink -f "${0}")" ] && [ "${fd}" != "${fd_path}" ]; then
close_me="true"
else
close_me="false"
fi
fi
fi
if [ "${fd_id}" -gt 2 ]; then
if [ "${close_me}" = "true" ]; then
eval "exec ${fd_id}>&-"
echo "[obtain-ip.sh] Closed fd ${fd_id} -> ${fd_path}"
else
# Try to log something more helpful when old busybox's readlink -f mangled it...
if [ "${fd}" = "${fd_path}" ]; then
fd_path="${fd_path} => $(readlink "${fd}")"
if [ ! -e "${fd}" ]; then
# Flag (potentially?) temporary items as such
fd_path="${fd_path} (temporary?)"
fi
fi
echo "[obtain-ip.sh] Left fd ${fd_id} -> ${fd_path} open"
fi
fi
done
./release-ip.sh
# NOTE: Prefer dhcpcd over udhcpc if available. That's what Nickel uses,
# and udhcpc appears to trip some insanely wonky corner cases on current FW (#6421)
if [ -x "/sbin/dhcpcd" ]; then
dhcpcd -d -t 30 -w "${INTERFACE}"
else
udhcpc -S -i "${INTERFACE}" -s /etc/udhcpc.d/default.script -b -q
fi