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|
# Read the symbols list and create regexs to use for processing readelf output.
BEGIN {
COUNT = 0;
sym_regex = "";
while ((getline line < SYMBOLS_FILE) > 0) {
if (line ~ /^ *#/ || line ~ /^$/)
continue;
split(line, fields);
symbol = fields[1];
SYMBOLS[++COUNT] = symbol;
if (sym_regex)
sym_regex = sym_regex "|";
sym_regex = sym_regex symbol;
}
SYMBOL_REGEX = "^(" sym_regex ")(@|$)";
WEAK_SYMBOL_REGEX = "^__(" sym_regx ")(@@|$)";
}
/^ OS\/ABI:/ {
ABI = $NF
}
{
# Unstripped libc's have '.symtab' section as well, and
# we should stop processing when we hit that
if ($0 ~ "^Symbol (.*)table '.symtab'")
nextfile;
# On x86, x86_64 and others, $8 is the symbol name, but on
# alpha, its $10, so rather use $NF, as it should be the
# last field
if ($NF ~ SYMBOL_REGEX) {
split($NF, symbol_array, /@|@@/);
# Don't add local symbols of versioned libc's
if (VERSIONED_LIBC && !symbol_array[2])
next;
# We have a versioned libc
if (symbol_array[2] && !VERSIONED_LIBC)
VERSIONED_LIBC = 1;
ADD = 1;
# Check that we do not add duplicates
for (y in PROCESSED_SYMBOLS) {
if (y == $NF) {
ADD = 0;
break;
}
}
if (ADD) {
SYMBOL_LIST[symbol_array[1]] = SYMBOL_LIST[symbol_array[1]] " " $NF;
PROCESSED_SYMBOLS[$NF] = $NF;
}
}
# No apparent need to handle weak __XXX symbols ... so disable
# until we have documentation on why ...
# If we do re-add this, need to update the `readelf` call in
# libsandbox/ to include the -h flag again.
next;
if (($5 == "WEAK") && ($NF ~ WEAK_SYMBOL_REGEX)) {
split($NF, symbol_array, /@@/);
# Don't add local symbols of versioned libc's
if (VERSIONED_LIBC && !symbol_array[2])
next;
# Blacklist __getcwd on FreeBSD
# Unleashed - May 2006
if ((symbol_array[1] == "__getcwd") && (ABI == "FreeBSD"))
next;
# We have a versioned libc
if (symbol_array[2] && !VERSIONED_LIBC)
VERSIONED_LIBC = 1;
ADD = 1;
# Check that we do not add duplicates
for (y in PROCESSED_SYMBOLS) {
if (y == $NF) {
ADD = 0;
break;
}
}
if (ADD) {
WEAK_SYMBOLS[SYMBOLS[x]] = WEAK_SYMBOLS[SYMBOLS[x]] " " $NF;
PROCESSED_SYMBOLS[$NF] = $NF;
}
}
}
END {
printf("#ifndef __symbols_h\n");
printf("#define __symbols_h\n\n");
SB_MAX_STRING_LEN = 0
# We use the order in SYMBOLS, as some wrappers depends on others ...
for (i = 1; i <= COUNT; ++i) {
sym_index = SYMBOLS[i];
full_count = split(SYMBOL_LIST[sym_index], sym_full_names);
if (length(sym_index) > SB_MAX_STRING_LEN)
SB_MAX_STRING_LEN = length(sym_index);
if (full_count == 0)
printf("#define SB_NR_%s (SB_NR_UNDEF - %i)\n", toupper(sym_index), i);
for (x in sym_full_names) {
split(sym_full_names[x], symbol_array, /@|@@/);
# Defualt symbol have '@@' and not '@', so name it by
# prepending '__' rather than the symbol version so
# that we know what the name is in libsandbox.c ...
# Also do this for non-versioned libc's ...
if (sym_full_names[x] ~ /@@/ || !symbol_array[2]) {
sym_is_default = 1;
sym_real_name = sym_index "_DEFAULT";
} else {
sym_is_default = 0;
sym_real_name = sym_full_names[x];
gsub(/@|\./, "_", sym_real_name);
}
# Avoid libc's symbol rename via #define. musl defines aliases as:
# #define mkstemp64 mkstemp
# #define mkstemps64 mkstemps
printf("#undef %s\n", sym_index);
printf("#define symname_%s \"%s\"\n", sym_real_name, sym_index);
# We handle non-versioned libc's by setting symver_*
# to NULL ...
if (!symbol_array[2])
printf("#define symver_%s NULL\n", sym_real_name);
else
printf("#define symver_%s \"%s\"\n", sym_real_name,
symbol_array[2]);
printf("#define STRING_NAME \"%s\"\n", sym_index);
printf("#define EXTERN_NAME %s\n", sym_index);
printf("#define WRAPPER_NAME %s\n", sym_real_name);
printf("#define WRAPPER_TRUE_NAME true_%s\n", sym_real_name);
printf("#define WRAPPER_SYMNAME symname_%s\n", sym_real_name);
printf("#define WRAPPER_SYMVER symver_%s\n", sym_real_name);
printf("#define SB_NR_%s %i\n", toupper(sym_index), i);
printf("#define WRAPPER_NR SB_NR_%s\n", toupper(sym_index));
printf("#include \"wrapper-funcs/%s.c\"\n", sym_index);
pre_check = "wrapper-funcs/" sym_index "_pre_check.c"
if (sym_is_default && system("test -e " srcdir "/" pre_check) == 0)
printf("#include \"%s\"\n", pre_check);
printf("#undef STRING_NAME\n");
printf("#undef EXTERN_NAME\n");
printf("#undef WRAPPER_NAME\n");
printf("#undef WRAPPER_TRUE_NAME\n");
printf("#undef WRAPPER_SYMNAME\n");
printf("#undef WRAPPER_SYMVER\n");
printf("#undef WRAPPER_NR\n");
printf("#undef WRAPPER_ARGS\n");
printf("#undef WRAPPER_ARGS_PROTO\n");
printf("#undef WRAPPER_SAFE\n");
printf("#undef WRAPPER_RET_TYPE\n");
printf("#undef WRAPPER_RET_DEFAULT\n");
printf("#undef WRAPPER_PRE_CHECKS\n");
if (symbol_array[2]) {
# Only add symbol versions for versioned libc's
if (sym_full_names[x] ~ /@@/)
printf("default_symbol_version(%s, %s, %s);\n",
sym_real_name, sym_index, symbol_array[2]);
else
printf("symbol_version(%s, %s, %s);\n",
sym_real_name, sym_index, symbol_array[2]);
} else {
# For non-versioned libc's we use strong aliases
printf("strong_alias(%s, %s);\n", sym_real_name,
sym_index);
}
if (WEAK_SYMBOLS[sym_index]) {
split(WEAK_SYMBOLS[sym_index], sym_weak_full);
for (y in sym_weak_full) {
split(sym_weak_full[y], sym_weak_array, /@@/);
# Add weak symbols for libc's like glibc that
# have them
if (sym_weak_array[1] == "__" sym_index)
printf("weak_alias(%s, %s);\n",
sym_real_name,
sym_weak_array[1]);
}
}
printf("\n");
}
}
printf("#define SB_MAX_STRING_LEN %i\n\n", SB_MAX_STRING_LEN);
printf("#endif /* __symbols_h */\n");
}
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