fcd2678171
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
136 lines
3.2 KiB
Bash
Executable File
136 lines
3.2 KiB
Bash
Executable File
#!/bin/sh
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# $FreeBSD$
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libkey() {
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libkey="lib_symbols_$1"
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patterns=[.+,/-]
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replacement=_
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while :; do
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case " ${libkey} " in
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*${patterns}*)
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libkey="${libkey%%${patterns}*}${replacement}${libkey#*${patterns}}"
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;;
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*)
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break
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;;
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esac
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done
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return 0
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}
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usage() {
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cat <<-EOF
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usage: $0 [-Uv] [-L LD_LIBRARY_PATH] file
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-L: Specify an alternative LD_LIBRARY_PATH for the library resolution.
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-U: Skip looking for unresolved symbols.
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-v: Show which library each symbol is resolved to.
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EOF
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exit 0
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}
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ret=0
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CHECK_UNRESOLVED=1
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VERBOSE_RESOLVED=0
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while getopts "L:Uv" flag; do
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case "${flag}" in
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L) LIB_PATH="${OPTARG}" ;;
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U) CHECK_UNRESOLVED=0 ;;
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v) VERBOSE_RESOLVED=1 ;;
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*) usage ;;
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esac
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done
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shift $((OPTIND-1))
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if ! [ -f "$1" ]; then
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echo "No such file or directory: $1" >&2
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exit 1
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fi
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mime=$(file -L --mime-type $1)
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isbin=0
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case $mime in
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*application/x-executable) isbin=1 ;;
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*application/x-sharedlib);;
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*) echo "Not an elf file" >&2 ; exit 1;;
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esac
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# Gather all symbols from the target
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unresolved_symbols=$(nm -u -D --format=posix "$1" | awk '$2 == "U" {print $1}' | tr '\n' ' ')
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[ ${isbin} -eq 1 ] && bss_symbols=$(nm -D --format=posix "$1" | awk '$2 == "B" && $4 != "" {print $1}' | tr '\n' ' ')
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if [ -n "${LIB_PATH}" ]; then
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for libc in /lib/libc.so.*; do
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LDD_ENV="LD_PRELOAD=${libc}"
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done
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LDD_ENV="${LDD_ENV} LD_LIBRARY_PATH=${LIB_PATH}"
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fi
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ldd_libs=$(env ${LDD_ENV} ldd $(realpath $1) | awk '{print $1 ":" $3}')
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# Check for useful libs
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list_libs=
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resolved_symbols=
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for lib in $(readelf -d $1 | awk '$2 ~ /\(?NEEDED\)?/ { sub(/\[/,"",$NF); sub(/\]/,"",$NF); print $NF }'); do
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echo -n "checking if $lib is needed: "
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if [ -n "${lib##/*}" ]; then
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for libpair in ${ldd_libs}; do
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case "${libpair}" in
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${lib}:*) libpath="${libpair#*:}" && break ;;
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esac
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done
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else
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libpath="${lib}"
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fi
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list_libs="$list_libs $lib"
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foundone=
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lib_symbols="$(nm -D --defined-only --format=posix "${libpath}" | awk '$2 ~ /C|R|D|T|W|B|V/ {print $1}' | tr '\n' ' ')"
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if [ ${CHECK_UNRESOLVED} -eq 1 ]; then
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# Save the global symbols for this lib
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libkey "${lib}"
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setvar "${libkey}" "${lib_symbols}"
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fi
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for fct in ${lib_symbols}; do
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case " ${unresolved_symbols} ${bss_symbols} " in
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*\ ${fct}\ *) foundone="${fct}" && break ;;
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esac
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done
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if [ -n "${foundone}" ]; then
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echo "yes... ${foundone}"
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else
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echo "no"
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ret=1
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fi
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done
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if [ ${CHECK_UNRESOLVED} -eq 1 ]; then
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# Add in crt1 symbols
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list_libs="${list_libs} crt1.o"
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lib_symbols="$(nm --defined-only --format=posix "/usr/lib/crt1.o" | awk '$2 ~ /C|R|D|T|W|B|V/ {print $1}' | tr '\n' ' ')"
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# Save the global symbols for this lib
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libkey "crt1.o"
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setvar "${libkey}" "${lib_symbols}"
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# Now search libs for all symbols and report missing ones.
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for sym in ${unresolved_symbols}; do
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found=0
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for lib in ${list_libs}; do
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libkey "${lib}"
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eval "lib_symbols=\"\${${libkey}}\""
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# lib_symbols now contains symbols for the lib.
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case " ${lib_symbols} " in
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*\ ${sym}\ *)
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[ ${VERBOSE_RESOLVED} -eq 1 ] &&
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echo "Resolved symbol ${sym} from ${lib}"
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found=1
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break
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;;
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esac
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done
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if [ $found -eq 0 ]; then
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echo "Unresolved symbol $sym"
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ret=1
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fi
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done
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fi
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exit ${ret}
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