# This awk script expects to get command-line files that are each

# the output of 'readelf -WSdr' on a single shared object, and named

# .../NAME.jmprel where NAME is the unadorned file name of the shared object.

# It writes "NAME: SYMBOL" for each PLT entry in NAME that refers to a

# symbol defined in the same object.

BEGIN { result = 0 }

FILENAME != lastfile {

  if (lastfile && jmprel_offset == 0 && rela_offset == 0 && rel_offset == 0) {

    print FILENAME ": *** failed to find expected output (readelf -WSdr)";

    result = 2;

  }

  lastfile = FILENAME;

  jmprel_offset = 0;

  rela_offset = 0;

  rel_offset = 0;

  delete section_offset_by_address;

}

/^Section Headers:/ { in_shdrs = 1; next }

in_shdrs && !/^ +\[/ { in_shdrs = 0 }

in_shdrs && /^ +\[/ { sub(/\[ +/, "[") }

in_shdrs {

  address = strtonum("0x" $4);

  offset = strtonum("0x" $5);

  section_offset_by_address[address] = offset;

}

in_shdrs { next }

$1 == "Offset" && $2 == "Info" { in_relocs = 1; next }

NF == 0 { in_relocs = 0 }

in_relocs && relocs_offset == jmprel_offset && NF >= 5 {

  # Relocations against GNU_IFUNC symbols are not shown as an hexadecimal

  # value, but rather as the resolver symbol followed by ().

  if ($4 ~ /\(\)/) {

    print whatfile, gensub(/@.*/, "", "g", $5)

  } else {

    symval = strtonum("0x" $4);

    if (symval != 0)

      print whatfile, gensub(/@.*/, "", "g", $5)

  }

}

in_relocs && relocs_offset == rela_offset && NF >= 5 {

  # Relocations against GNU_IFUNC symbols are not shown as an hexadecimal

  # value, but rather as the resolver symbol followed by ().

  if ($4 ~ /\(\)/) {

    print whatfile, gensub(/@.*/, "", "g", $5), "RELA", $3

  } else {

    symval = strtonum("0x" $4);

    if (symval != 0)

      print whatfile, gensub(/@.*/, "", "g", $5), "RELA", $3

  }

}

in_relocs && relocs_offset == rel_offset && NF >= 5 {

  # Relocations against GNU_IFUNC symbols are not shown as an hexadecimal

  # value, but rather as the resolver symbol followed by ().

  if ($4 ~ /\(\)/) {

    print whatfile, gensub(/@.*/, "", "g", $5), "REL", $3

  } else {

    symval = strtonum("0x" $4);

    if (symval != 0)

      print whatfile, gensub(/@.*/, "", "g", $5), "REL", $3

  }

}

in_relocs { next }

$1 == "Relocation" && $2 == "section" && $5 == "offset" {

  relocs_offset = strtonum($6);

  whatfile = gensub(/^.*\/([^/]+)\.jmprel$/, "\\1:", 1, FILENAME);

  next

}

$2 == "(JMPREL)" {

  jmprel_addr = strtonum($3);

  if (jmprel_addr in section_offset_by_address) {

    jmprel_offset = section_offset_by_address[jmprel_addr];

  } else {

    print FILENAME ": *** DT_JMPREL does not match any section's address";

    result = 2;

  }

  next

}

$2 == "(RELA)" {

  rela_addr = strtonum($3);

  if (rela_addr in section_offset_by_address) {

    rela_offset = section_offset_by_address[rela_addr];

  } else {

    print FILENAME ": *** DT_RELA does not match any section's address";

    result = 2;

  }

  next

}

$2 == "(REL)" {

  rel_addr = strtonum($3);

  if (rel_addr in section_offset_by_address) {

    rel_offset = section_offset_by_address[rel_addr];

  } else {

    print FILENAME ": *** DT_REL does not match any section's address";

    result = 2;

  }

  next

}

END { exit(result) }