nixpkgs/pkgs/build-support/setup-hooks/auto-patchelf.sh
aszlig 4a6e3e4185
autoPatchelfHook: Skip on missing segment headers
If the file in question is not a shared object file but an ELF, we
really want to skip the file, because we won't have anything to patch
there.

For example if the file is created via "gcc -c -o foo.o foo.c", we don't
get a segment header and so far autoPatchelf was trying to patch such a
file.

By checking for missing segment headers, we're now no longer going to
attempt patching such a file.

Signed-off-by: aszlig <aszlig@nix.build>
Reported-by: Sander van der Burg <svanderburg@gmail.com>
2018-11-26 01:58:36 +01:00

235 lines
7.6 KiB
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declare -a autoPatchelfLibs
gatherLibraries() {
autoPatchelfLibs+=("$1/lib")
}
addEnvHooks "$targetOffset" gatherLibraries
isExecutable() {
# For dynamically linked ELF files it would be enough to check just for the
# INTERP section. However, we won't catch statically linked executables as
# they only have an ELF type of EXEC but no INTERP.
#
# So what we do here is just check whether *either* the ELF type is EXEC
# *or* there is an INTERP section. This also catches position-independent
# executables, as they typically have an INTERP section but their ELF type
# is DYN.
LANG=C readelf -h -l "$1" 2> /dev/null \
| grep -q '^ *Type: *EXEC\>\|^ *INTERP\>'
}
# We cache dependencies so that we don't need to search through all of them on
# every consecutive call to findDependency.
declare -a cachedDependencies
addToDepCache() {
local existing
for existing in "${cachedDependencies[@]}"; do
if [ "$existing" = "$1" ]; then return; fi
done
cachedDependencies+=("$1")
}
declare -gi depCacheInitialised=0
declare -gi doneRecursiveSearch=0
declare -g foundDependency
getDepsFromSo() {
ldd "$1" 2> /dev/null | sed -n -e 's/[^=]*=> *\(.\+\) \+([^)]*)$/\1/p'
}
populateCacheWithRecursiveDeps() {
local so found foundso
for so in "${cachedDependencies[@]}"; do
for found in $(getDepsFromSo "$so"); do
local libdir="${found%/*}"
local base="${found##*/}"
local soname="${base%.so*}"
for foundso in "${found%/*}/$soname".so*; do
addToDepCache "$foundso"
done
done
done
}
getSoArch() {
objdump -f "$1" | sed -ne 's/^architecture: *\([^,]\+\).*/\1/p'
}
# NOTE: If you want to use this function outside of the autoPatchelf function,
# keep in mind that the dependency cache is only valid inside the subshell
# spawned by the autoPatchelf function, so invoking this directly will possibly
# rebuild the dependency cache. See the autoPatchelf function below for more
# information.
findDependency() {
local filename="$1"
local arch="$2"
local lib dep
if [ $depCacheInitialised -eq 0 ]; then
for lib in "${autoPatchelfLibs[@]}"; do
for so in "$lib/"*.so*; do addToDepCache "$so"; done
done
depCacheInitialised=1
fi
for dep in "${cachedDependencies[@]}"; do
if [ "$filename" = "${dep##*/}" ]; then
if [ "$(getSoArch "$dep")" = "$arch" ]; then
foundDependency="$dep"
return 0
fi
fi
done
# Populate the dependency cache with recursive dependencies *only* if we
# didn't find the right dependency so far and afterwards run findDependency
# again, but this time with $doneRecursiveSearch set to 1 so that it won't
# recurse again (and thus infinitely).
if [ $doneRecursiveSearch -eq 0 ]; then
populateCacheWithRecursiveDeps
doneRecursiveSearch=1
findDependency "$filename" "$arch" || return 1
return 0
fi
return 1
}
autoPatchelfFile() {
local dep rpath="" toPatch="$1"
local interpreter="$(< "$NIX_CC/nix-support/dynamic-linker")"
if isExecutable "$toPatch"; then
patchelf --set-interpreter "$interpreter" "$toPatch"
if [ -n "$runtimeDependencies" ]; then
for dep in $runtimeDependencies; do
rpath="$rpath${rpath:+:}$dep/lib"
done
fi
fi
echo "searching for dependencies of $toPatch" >&2
# We're going to find all dependencies based on ldd output, so we need to
# clear the RPATH first.
patchelf --remove-rpath "$toPatch"
local missing="$(
ldd "$toPatch" 2> /dev/null | \
sed -n -e 's/^[\t ]*\([^ ]\+\) => not found.*/\1/p'
)"
# This ensures that we get the output of all missing dependencies instead
# of failing at the first one, because it's more useful when working on a
# new package where you don't yet know its dependencies.
local -i depNotFound=0
for dep in $missing; do
echo -n " $dep -> " >&2
if findDependency "$dep" "$(getSoArch "$toPatch")"; then
rpath="$rpath${rpath:+:}${foundDependency%/*}"
echo "found: $foundDependency" >&2
else
echo "not found!" >&2
depNotFound=1
fi
done
# This makes sure the builder fails if we didn't find a dependency, because
# the stdenv setup script is run with set -e. The actual error is emitted
# earlier in the previous loop.
[ $depNotFound -eq 0 ]
if [ -n "$rpath" ]; then
echo "setting RPATH to: $rpath" >&2
patchelf --set-rpath "$rpath" "$toPatch"
fi
}
# Can be used to manually add additional directories with shared object files
# to be included for the next autoPatchelf invocation.
addAutoPatchelfSearchPath() {
local -a findOpts=()
# XXX: Somewhat similar to the one in the autoPatchelf function, maybe make
# it DRY someday...
while [ $# -gt 0 ]; do
case "$1" in
--) shift; break;;
--no-recurse) shift; findOpts+=("-maxdepth" 1);;
--*)
echo "addAutoPatchelfSearchPath: ERROR: Invalid command line" \
"argument: $1" >&2
return 1;;
*) break;;
esac
done
cachedDependencies+=(
$(find "$@" "${findOpts[@]}" \! -type d \
\( -name '*.so' -o -name '*.so.*' \))
)
}
autoPatchelf() {
local norecurse=
while [ $# -gt 0 ]; do
case "$1" in
--) shift; break;;
--no-recurse) shift; norecurse=1;;
--*)
echo "autoPatchelf: ERROR: Invalid command line" \
"argument: $1" >&2
return 1;;
*) break;;
esac
done
if [ $# -eq 0 ]; then
echo "autoPatchelf: No paths to patch specified." >&2
return 1
fi
echo "automatically fixing dependencies for ELF files" >&2
# Add all shared objects of the current output path to the start of
# cachedDependencies so that it's choosen first in findDependency.
addAutoPatchelfSearchPath ${norecurse:+--no-recurse} -- "$@"
# Here we actually have a subshell, which also means that
# $cachedDependencies is final at this point, so whenever we want to run
# findDependency outside of this, the dependency cache needs to be rebuilt
# from scratch, so keep this in mind if you want to run findDependency
# outside of this function.
while IFS= read -r -d $'\0' file; do
isELF "$file" || continue
segmentHeaders="$(LANG=C readelf -l "$file")"
# Skip if the ELF file doesn't have segment headers (eg. object files).
echo "$segmentHeaders" | grep -q '^Program Headers:' || continue
if isExecutable "$file"; then
# Skip if the executable is statically linked.
echo "$segmentHeaders" | grep -q "^ *INTERP\\>" || continue
fi
autoPatchelfFile "$file"
done < <(find "$@" ${norecurse:+-maxdepth 1} -type f -print0)
}
# XXX: This should ultimately use fixupOutputHooks but we currently don't have
# a way to enforce the order. If we have $runtimeDependencies set, the setup
# hook of patchelf is going to ruin everything and strip out those additional
# RPATHs.
#
# So what we do here is basically run in postFixup and emulate the same
# behaviour as fixupOutputHooks because the setup hook for patchelf is run in
# fixupOutput and the postFixup hook runs later.
postFixupHooks+=('
if [ -z "$dontAutoPatchelf" ]; then
autoPatchelf -- $(for output in $outputs; do
[ -e "${!output}" ] || continue
echo "${!output}"
done)
fi
')