tools/build/check-links.sh

   1 #!/bin/sh
   2
   3 libkey() {
   4         libkey="lib_symbols_$1"
   5         patterns=[.+,/-]
   6         replacement=_
   7         while :; do
   8                 case " ${libkey} " in
   9                         *${patterns}*)
  10                                 libkey="${libkey%%${patterns}*}${replacement}${libkey#*${patterns}}"
  11                                 ;;
  12                         *)
  13                                 break
  14                                 ;;
  15                 esac
  16         done
  17         return 0
  18 }
  19
  20 usage() {
  21         cat <<-EOF
  22         usage: $0 [-Uv] [-L LD_LIBRARY_PATH] file
  23                -L:       Specify an alternative LD_LIBRARY_PATH for the library resolution.
  24                -U:       Skip looking for unresolved symbols.
  25                -v:       Show which library each symbol is resolved to.
  26         EOF
  27         exit 0
  28 }
  29
  30 ret=0
  31 CHECK_UNRESOLVED=1
  32 VERBOSE_RESOLVED=0
  33 while getopts "L:Uv" flag; do
  34         case "${flag}" in
  35                 L) LIB_PATH="${OPTARG}" ;;
  36                 U) CHECK_UNRESOLVED=0 ;;
  37                 v) VERBOSE_RESOLVED=1 ;;
  38                 *) usage ;;
  39         esac
  40 done
  41 shift $((OPTIND-1))
  42
  43 if ! [ -f "$1" ]; then
  44         echo "No such file or directory: $1" >&2
  45         exit 1
  46 fi
  47
  48 mime=$(file -L --mime-type $1)
  49 isbin=0
  50 case $mime in
  51 *application/x-executable|*application/x-pie-executable) isbin=1 ;;
  52 *application/x-sharedlib);;
  53 *) echo "Not an elf file" >&2 ; exit 1;;
  54 esac
  55
  56 # Gather all symbols from the target
  57 unresolved_symbols=$(nm -u -D --format=posix "$1" | awk '$2 == "U" {print $1}' | tr '\n' ' ')
  58 [ ${isbin} -eq 1 ] && bss_symbols=$(nm -D --format=posix "$1" | awk '$2 == "B" && $4 != "" {print $1}' | tr '\n' ' ')
  59 if [ -n "${LIB_PATH}" ]; then
  60         for libc in /lib/libc.so.*; do
  61                 LDD_ENV="LD_PRELOAD=${libc}"
  62         done
  63         LDD_ENV="${LDD_ENV} LD_LIBRARY_PATH=${LIB_PATH}"
  64 fi
  65
  66 ldd_libs=$(env ${LDD_ENV} ldd $(realpath $1) | awk '{print $1 ":" $3}')
  67
  68 # Check for useful libs
  69 list_libs=
  70 resolved_symbols=
  71 for lib in $(readelf -d $1 | awk '$2 ~ /\(?NEEDED\)?/ { sub(/\[/,"",$NF); sub(/\]/,"",$NF); print $NF }'); do
  72         echo -n "checking if $lib is needed: "
  73         if [ -n "${lib##/*}" ]; then
  74                 for libpair in ${ldd_libs}; do
  75                         case "${libpair}" in
  76                                 ${lib}:*) libpath="${libpair#*:}" && break ;;
  77                         esac
  78                 done
  79         else
  80                 libpath="${lib}"
  81         fi
  82         list_libs="$list_libs $lib"
  83         foundone=
  84         lib_symbols="$(nm -D --defined-only --format=posix "${libpath}" | awk '$2 ~ /C|R|D|T|W|B|V/ {print $1}' | tr '\n' ' ')"
  85         if [ ${CHECK_UNRESOLVED} -eq 1 ]; then
  86                 # Save the global symbols for this lib
  87                 libkey "${lib}"
  88                 setvar "${libkey}" "${lib_symbols}"
  89         fi
  90         for fct in ${lib_symbols}; do
  91                 case " ${unresolved_symbols} ${bss_symbols} " in
  92                         *\ ${fct}\ *) foundone="${fct}" && break ;;
  93                 esac
  94         done
  95         if [ -n "${foundone}" ]; then
  96                 echo "yes... ${foundone}"
  97         else
  98                 echo "no"
  99                 ret=1
 100         fi
 101 done
 102
 103 if [ ${CHECK_UNRESOLVED} -eq 1 ]; then
 104         # Add in crt1 symbols
 105         list_libs="${list_libs} crt1.o"
 106         lib_symbols="$(nm --defined-only --format=posix "/usr/lib/crt1.o" | awk '$2 ~ /C|R|D|T|W|B|V/ {print $1}' | tr '\n' ' ')"
 107         # Save the global symbols for this lib
 108         libkey "crt1.o"
 109         setvar "${libkey}" "${lib_symbols}"
 110
 111         # Now search libs for all symbols and report missing ones.
 112         for sym in ${unresolved_symbols}; do
 113                 found=0
 114                 for lib in ${list_libs}; do
 115                         libkey "${lib}"
 116                         eval "lib_symbols=\"\${${libkey}}\""
 117                         # lib_symbols now contains symbols for the lib.
 118                         case " ${lib_symbols} " in
 119                                 *\ ${sym}\ *)
 120                                         [ ${VERBOSE_RESOLVED} -eq 1 ] &&
 121                                             echo "Resolved symbol ${sym} from ${lib}"
 122                                         found=1
 123                                         break
 124                                         ;;
 125                         esac
 126                 done
 127                 if [ $found -eq 0 ]; then
 128                         echo "Unresolved symbol $sym"
 129                         ret=1
 130                 fi
 131         done
 132 fi
 133
 134 exit ${ret}