glibc/scripts/localplt.awk

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# 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) {
print FILENAME ": *** failed to find expected output (readelf -WSdr)";
result = 2;
}
lastfile = FILENAME;
jmprel_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 { 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
}
END { exit(result) }