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freebsd/tools/build/check-links.sh
Bryan Drewery fcd2678171 Allow specifying an alternative LD_LIBRARY_PATH for the ldd(1) lookup.
This is needed to be able to run check-links.sh against a "sysrooted"
binary while ensuring that the ldd(1) call done on the host uses the
host libc.  It is not possible to set LD_LIBRARY_PATH before calling
check-links.sh as then the "sysrooted" libc would be incorrectly used.

A LD_PRELOAD=libc.so is used to ldd(1) as it needs to use the host libc
to run.  ldd(1) is a simple wrapper around execve(2) and dlopen(2) with
env LD_TRACE_LOADED_OBJECTS set.  Due to the dlopen(2) restriction on
shared library tracing ldd(1) is still required for this lookup.

Sponsored by:	EMC / Isilon Storage Division
2016-01-19 22:42:16 +00:00

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#!/bin/sh
# $FreeBSD$
libkey() {
libkey="lib_symbols_$1"
patterns=[.+,/-]
replacement=_
while :; do
case " ${libkey} " in
*${patterns}*)
libkey="${libkey%%${patterns}*}${replacement}${libkey#*${patterns}}"
;;
*)
break
;;
esac
done
return 0
}
usage() {
cat <<-EOF
usage: $0 [-Uv] [-L LD_LIBRARY_PATH] file
-L: Specify an alternative LD_LIBRARY_PATH for the library resolution.
-U: Skip looking for unresolved symbols.
-v: Show which library each symbol is resolved to.
EOF
exit 0
}
ret=0
CHECK_UNRESOLVED=1
VERBOSE_RESOLVED=0
while getopts "L:Uv" flag; do
case "${flag}" in
L) LIB_PATH="${OPTARG}" ;;
U) CHECK_UNRESOLVED=0 ;;
v) VERBOSE_RESOLVED=1 ;;
*) usage ;;
esac
done
shift $((OPTIND-1))
if ! [ -f "$1" ]; then
echo "No such file or directory: $1" >&2
exit 1
fi
mime=$(file -L --mime-type $1)
isbin=0
case $mime in
*application/x-executable) isbin=1 ;;
*application/x-sharedlib);;
*) echo "Not an elf file" >&2 ; exit 1;;
esac
# Gather all symbols from the target
unresolved_symbols=$(nm -u -D --format=posix "$1" | awk '$2 == "U" {print $1}' | tr '\n' ' ')
[ ${isbin} -eq 1 ] && bss_symbols=$(nm -D --format=posix "$1" | awk '$2 == "B" && $4 != "" {print $1}' | tr '\n' ' ')
if [ -n "${LIB_PATH}" ]; then
for libc in /lib/libc.so.*; do
LDD_ENV="LD_PRELOAD=${libc}"
done
LDD_ENV="${LDD_ENV} LD_LIBRARY_PATH=${LIB_PATH}"
fi
ldd_libs=$(env ${LDD_ENV} ldd $(realpath $1) | awk '{print $1 ":" $3}')
# Check for useful libs
list_libs=
resolved_symbols=
for lib in $(readelf -d $1 | awk '$2 ~ /\(?NEEDED\)?/ { sub(/\[/,"",$NF); sub(/\]/,"",$NF); print $NF }'); do
echo -n "checking if $lib is needed: "
if [ -n "${lib##/*}" ]; then
for libpair in ${ldd_libs}; do
case "${libpair}" in
${lib}:*) libpath="${libpair#*:}" && break ;;
esac
done
else
libpath="${lib}"
fi
list_libs="$list_libs $lib"
foundone=
lib_symbols="$(nm -D --defined-only --format=posix "${libpath}" | awk '$2 ~ /C|R|D|T|W|B|V/ {print $1}' | tr '\n' ' ')"
if [ ${CHECK_UNRESOLVED} -eq 1 ]; then
# Save the global symbols for this lib
libkey "${lib}"
setvar "${libkey}" "${lib_symbols}"
fi
for fct in ${lib_symbols}; do
case " ${unresolved_symbols} ${bss_symbols} " in
*\ ${fct}\ *) foundone="${fct}" && break ;;
esac
done
if [ -n "${foundone}" ]; then
echo "yes... ${foundone}"
else
echo "no"
ret=1
fi
done
if [ ${CHECK_UNRESOLVED} -eq 1 ]; then
# Add in crt1 symbols
list_libs="${list_libs} crt1.o"
lib_symbols="$(nm --defined-only --format=posix "/usr/lib/crt1.o" | awk '$2 ~ /C|R|D|T|W|B|V/ {print $1}' | tr '\n' ' ')"
# Save the global symbols for this lib
libkey "crt1.o"
setvar "${libkey}" "${lib_symbols}"
# Now search libs for all symbols and report missing ones.
for sym in ${unresolved_symbols}; do
found=0
for lib in ${list_libs}; do
libkey "${lib}"
eval "lib_symbols=\"\${${libkey}}\""
# lib_symbols now contains symbols for the lib.
case " ${lib_symbols} " in
*\ ${sym}\ *)
[ ${VERBOSE_RESOLVED} -eq 1 ] &&
echo "Resolved symbol ${sym} from ${lib}"
found=1
break
;;
esac
done
if [ $found -eq 0 ]; then
echo "Unresolved symbol $sym"
ret=1
fi
done
fi
exit ${ret}