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// SPDX-License-Identifier: GPL-2.0-or-later
#define _GNU_SOURCE /* memmem() */
#include <subcmd/parse-options.h>
#include <stdlib.h>
#include <string.h>
#include <libgen.h>
#include <stdio.h>
#include <ctype.h>
#include <objtool/objtool.h>
#include <objtool/warn.h>
#include <objtool/arch.h>
#include <objtool/klp.h>
#include <objtool/util.h>
#include <arch/special.h>
#include <linux/align.h>
#include <linux/objtool_types.h>
#include <linux/livepatch_external.h>
#include <linux/stringify.h>
#include <linux/string.h>
#include <linux/jhash.h>
#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
struct elfs {
struct elf *orig, *patched, *out;
const char *modname;
};
struct export {
struct hlist_node hash;
char *mod, *sym;
};
bool debug, debug_correlate, debug_clone;
int indent;
static const char * const klp_diff_usage[] = {
"objtool klp diff [<options>] <in1.o> <in2.o> <out.o>",
NULL,
};
static const struct option klp_diff_options[] = {
OPT_GROUP("Options:"),
OPT_BOOLEAN('d', "debug", &debug, "enable all debug output"),
OPT_BOOLEAN(0, "debug-correlate", &debug_correlate, "enable correlation debug output"),
OPT_BOOLEAN(0, "debug-clone", &debug_clone, "enable cloning debug output"),
OPT_END(),
};
static DEFINE_HASHTABLE(exports, 15);
static char *escape_str(const char *orig)
{
size_t len = 0;
const char *a;
char *b, *new;
for (a = orig; *a; a++) {
switch (*a) {
case '\001': len += 5; break;
case '\n':
case '\t': len += 2; break;
default: len++;
}
}
new = malloc(len + 1);
if (!new)
return NULL;
for (a = orig, b = new; *a; a++) {
switch (*a) {
case '\001': memcpy(b, "<SOH>", 5); b += 5; break;
case '\n': *b++ = '\\'; *b++ = 'n'; break;
case '\t': *b++ = '\\'; *b++ = 't'; break;
default: *b++ = *a;
}
}
*b = '\0';
return new;
}
static int read_exports(void)
{
const char *symvers = "Module.symvers";
char line[1024], *path = NULL;
unsigned int line_num = 1;
FILE *file;
file = fopen(symvers, "r");
if (!file) {
path = top_level_dir(symvers);
if (!path) {
ERROR("can't open '%s', \"objtool diff\" should be run from the kernel tree", symvers);
return -1;
}
file = fopen(path, "r");
if (!file) {
ERROR_GLIBC("fopen");
return -1;
}
}
while (fgets(line, 1024, file)) {
char *sym, *mod, *type;
struct export *export;
sym = strchr(line, '\t');
if (!sym) {
ERROR("malformed Module.symvers (sym) at line %d", line_num);
return -1;
}
*sym++ = '\0';
mod = strchr(sym, '\t');
if (!mod) {
ERROR("malformed Module.symvers (mod) at line %d", line_num);
return -1;
}
*mod++ = '\0';
type = strchr(mod, '\t');
if (!type) {
ERROR("malformed Module.symvers (type) at line %d", line_num);
return -1;
}
*type++ = '\0';
if (*sym == '\0' || *mod == '\0') {
ERROR("malformed Module.symvers at line %d", line_num);
return -1;
}
export = calloc(1, sizeof(*export));
if (!export) {
ERROR_GLIBC("calloc");
return -1;
}
export->mod = strdup(mod);
if (!export->mod) {
ERROR_GLIBC("strdup");
return -1;
}
export->sym = strdup(sym);
if (!export->sym) {
ERROR_GLIBC("strdup");
return -1;
}
hash_add(exports, &export->hash, str_hash(sym));
}
free(path);
fclose(file);
return 0;
}
static int read_sym_checksums(struct elf *elf)
{
struct section *sec;
sec = find_section_by_name(elf, ".discard.sym_checksum");
if (!sec) {
ERROR("'%s' missing .discard.sym_checksum section, file not processed by 'objtool klp checksum'?",
elf->name);
return -1;
}
if (!sec->rsec) {
ERROR("missing reloc section for .discard.sym_checksum");
return -1;
}
if (sec_size(sec) % sizeof(struct sym_checksum)) {
ERROR("struct sym_checksum size mismatch");
return -1;
}
for (int i = 0; i < sec_size(sec) / sizeof(struct sym_checksum); i++) {
struct sym_checksum *sym_checksum;
struct reloc *reloc;
struct symbol *sym;
sym_checksum = (struct sym_checksum *)sec->data->d_buf + i;
reloc = find_reloc_by_dest(elf, sec, i * sizeof(*sym_checksum));
if (!reloc) {
ERROR("can't find reloc for sym_checksum[%d]", i);
return -1;
}
sym = reloc->sym;
if (is_sec_sym(sym)) {
ERROR("not sure how to handle section %s", sym->name);
return -1;
}
if (is_func_sym(sym) || is_object_sym(sym))
sym->csum.checksum = sym_checksum->checksum;
}
return 0;
}
static struct symbol *first_file_symbol(struct elf *elf)
{
struct symbol *sym;
for_each_sym(elf, sym) {
if (is_file_sym(sym))
return sym;
}
return NULL;
}
static struct symbol *next_file_symbol(struct elf *elf, struct symbol *sym)
{
for_each_sym_continue(elf, sym) {
if (is_file_sym(sym))
return sym;
}
return NULL;
}
/*
* Certain static local variables should never be correlated. They will be
* used in place rather than referencing the originals.
*/
static bool is_uncorrelated_static_local(struct symbol *sym)
{
static const char * const vars[] = {
"__already_done",
"__func__",
"__key",
"__warned",
"_entry",
"_entry_ptr",
"_rs",
"descriptor",
"CSWTCH",
};
const char *dot;
if (!is_object_sym(sym) || !is_local_sym(sym))
return false;
/* WARN_ONCE, etc */
if (!strcmp(sym->sec->name, ".data..once"))
return true;
dot = strchr(sym->name, '.');
if (!dot)
return false;
for (int i = 0; i < ARRAY_SIZE(vars); i++) {
size_t len = strlen(vars[i]);
/* GCC: <var>.<id> */
if (strstarts(sym->name, vars[i]) && (sym->name[len] == '.'))
return true;
/* Clang: <func>.<var>[.<id>] */
if (strstarts(dot + 1, vars[i]) &&
(dot[1 + len] == '.' || dot[1 + len] == '\0'))
return true;
}
return false;
}
/*
* .L symbols are assembler-local labels not present in kallsyms. They must
* never become KLP relocations; instead their data is cloned into the patch
* module. This covers .Ltmp* (Clang temp labels), .L__const.* (Clang local
* constants), and any other assembler-local pattern.
*/
static bool is_local_label(struct symbol *sym)
{
return strstarts(sym->name, ".L");
}
static bool is_special_section(struct section *sec)
{
static const char * const specials[] = {
".altinstructions",
".kcfi_traps",
".smp_locks",
"__bug_table",
"__ex_table",
"__jump_table",
"__mcount_loc",
/*
* Extract .static_call_sites here to inherit non-module
* preferential treatment. The later static call processing
* during klp module build will be skipped when it sees this
* section already exists.
*/
".static_call_sites",
};
static const char * const non_special_discards[] = {
".discard.addressable",
".discard.sym_checksum",
};
if (is_text_sec(sec))
return false;
for (int i = 0; i < ARRAY_SIZE(specials); i++) {
if (!strcmp(sec->name, specials[i]))
return true;
}
/* Most .discard data sections are special */
for (int i = 0; i < ARRAY_SIZE(non_special_discards); i++) {
if (!strcmp(sec->name, non_special_discards[i]))
return false;
}
return strstarts(sec->name, ".discard.");
}
/*
* These sections are referenced by special sections but aren't considered
* special sections themselves.
*/
static bool is_special_section_aux(struct section *sec)
{
static const char * const specials_aux[] = {
".altinstr_replacement",
".altinstr_aux",
};
for (int i = 0; i < ARRAY_SIZE(specials_aux); i++) {
if (!strcmp(sec->name, specials_aux[i]))
return true;
}
return false;
}
/*
* Symbols created by ___ADDRESSABLE() are only used to convince the toolchain
* not to optimize out the referenced symbol.
*/
static bool is_addressable_sym(struct symbol *sym)
{
return !strcmp(sym->sec->name, ".discard.addressable");
}
/*
* ABS symbols are typically assembly .set/.equ constants which are never
* referenced by relocations. (Exclude FILE symbols which are also SHN_ABS.)
*/
static bool is_abs_sym(struct symbol *sym)
{
return sym->sym.st_shndx == SHN_ABS && !is_file_sym(sym);
}
static bool is_initcall_sym(struct symbol *sym)
{
return strstarts(sym->name, "__initcall__") ||
strstarts(sym->name, "__initstub__");
}
/*
* Some .rodata is anonymous and can't be correlated due to there being no
* symbol names.
*
* The .rodata.cst* sections aren't technically anonymous, they're SHF_MERGE
* constant pool sections containing small fixed-size data (lookup tables,
* bitmasks) which are only read by value, so pointer equivalence isn't needed.
* They are typically referenced by UBSAN data sections.
*/
static bool is_anonymous_rodata(struct symbol *sym)
{
return is_rodata_sec(sym->sec) &&
(!is_object_sym(sym) || strstarts(sym->sec->name, ".rodata.cst"));
}
/*
* These symbols should never be correlated, so their local patched versions
* are used instead of linking to the originals.
*/
static bool dont_correlate(struct symbol *sym)
{
return is_file_sym(sym) ||
is_null_sym(sym) ||
is_sec_sym(sym) ||
is_abs_sym(sym) ||
is_prefix_func(sym) ||
is_uncorrelated_static_local(sym) ||
is_local_label(sym) ||
is_string_sec(sym->sec) ||
is_anonymous_rodata(sym) ||
is_initcall_sym(sym) ||
is_addressable_sym(sym) ||
is_special_section(sym->sec) ||
is_special_section_aux(sym->sec);
}
static const char *llvm_suffix(const char *name)
{
return strstr(name, ".llvm.");
}
static bool is_llvm_sym(struct symbol *sym)
{
return llvm_suffix(sym->name);
}
/*
* Determine if two symbols have compatible source file origins:
*
* - If both symbols are local, only return true if they belong to the same
* ELF file symbol.
*
* - If both symbols are global, always return true, as globals don't have
* file associations.
*
* - If they have different scopes, also return true, as the patch might have
* changed the symbol's scope.
*
* Works for both same-ELF (direct pointer compare) and cross-ELF
* (compare via file->twin) cases.
*/
static bool maybe_same_file(struct symbol *sym1, struct symbol *sym2)
{
if (!sym1->file || !sym2->file)
return true;
if (sym1->file == sym2->file)
return true;
return sym1->file->twin == sym2->file;
}
/*
* Similar to maybe_same_file(), but strict: no scope changes allowed.
*
* Works for both same-ELF (direct pointer compare) and cross-ELF
* (compare via file->twin) cases.
*/
static bool same_file(struct symbol *sym1, struct symbol *sym2)
{
if (llvm_suffix(sym1->name) && llvm_suffix(sym2->name))
return true;
if (!sym1->file && !sym2->file)
return true;
if (!sym1->file || !sym2->file)
return false;
if (sym1->file == sym2->file)
return true;
return sym1->file->twin == sym2->file;
}
/*
* Is it a local symbol, or at least was it local in the translation unit
* before LLVM promoted it?
*/
static bool is_tu_local_sym(struct symbol *sym)
{
return is_local_sym(sym) || is_llvm_sym(sym);
}
/*
* Try to find sym1's twin in patched using deterministic matching.
*
* Multiple symbols can share a demangled name (e.g., static functions in
* different TUs). This function counts same-named candidates through a
* funnel of progressively tighter filters. Each level is a strict subset
* of the previous one.
*
* The widest level that yields a 1:1 match wins. Narrower levels are only
* needed when the wider level is ambiguous (count > 1).
*
* Candidates are pre-filtered by maybe_same_file(), which narrows most
* local symbols to their own TU. For example, 19 different static
* type_show() functions across vmlinux.o each see only one candidate after
* pre-filtering, so they match immediately at Level 1.
*
* Level 1 (name): Works when the demangled name is unique after
* pre-filtering. Handles most symbols: unique globals like copy_signal(),
* or per-TU locals like pcspkr_probe().
*
* Level 2 (scope): Filters by local-vs-global (TU-local-vs-not). Example:
* parse_header() exists as both a static and a global function. Level 1
* sees both (same demangled name), but Level 2 separates them by scope.
*
* Level 3 (file): Strict file matching via same_file(), which rejects scope
* changes. Example: LLVM-promoted foo.llvm.12345 (global, no FILE symbol)
* vs genuine local foo (has FILE symbol). Both are TU-local so Level 2
* can't distinguish them, but same_file() rejects the pair because one has
* a file association and the other doesn't.
*
* Level 4 (checksum): Distinguishes by function checksum. Example:
* usb_devnode.llvm.AAA and usb_devnode.llvm.BBB are two LLVM-promoted
* functions from different TUs with the same demangled name. After a TU
* change, the .llvm. hashes change but the functions themselves may be
* unchanged. Level 4 matches each to the patched candidate with the
* same checksum.
*/
static struct symbol *find_twin(struct elfs *e, struct symbol *sym1)
{
struct symbol *name_last = NULL, *scope_last = NULL,
*file_last = NULL, *csum_last = NULL;
unsigned int name_orig = 0, name_patched = 0;
unsigned int scope_orig = 0, scope_patched = 0;
unsigned int file_orig = 0, file_patched = 0;
unsigned int csum_orig = 0, csum_patched = 0;
struct symbol *sym2, *match = NULL;
/* Count orig candidates */
for_each_sym_by_demangled_name(e->orig, sym1->demangled_name, sym2) {
if (sym2->twin || sym1->type != sym2->type || sym2->dont_correlate ||
(!maybe_same_file(sym1, sym2)))
continue;
/* Level 1: name match (widest filter) */
name_orig++;
/* Level 2: scope (scope changes allowed) */
if (is_tu_local_sym(sym1) != is_tu_local_sym(sym2))
continue;
scope_orig++;
/* Level 3: file (scope changes disallowed) */
if (!same_file(sym1, sym2))
continue;
file_orig++;
/* Level 4: checksum (unchanged symbols) */
if (sym1->len != sym2->len || !sym1->csum.checksum ||
sym1->csum.checksum != sym2->csum.checksum)
continue;
csum_orig++;
}
/* Count patched candidates */
for_each_sym_by_demangled_name(e->patched, sym1->demangled_name, sym2) {
if (sym2->twin || sym1->type != sym2->type || sym2->dont_correlate ||
!maybe_same_file(sym1, sym2))
continue;
/* Level 1 */
name_patched++;
name_last = sym2;
/* Level 2 */
if (is_tu_local_sym(sym1) != is_tu_local_sym(sym2))
continue;
scope_patched++;
scope_last = sym2;
/* Level 3 */
if (!same_file(sym1, sym2))
continue;
file_patched++;
file_last = sym2;
/* Level 4 */
if (sym1->len != sym2->len || !sym1->csum.checksum ||
sym1->csum.checksum != sym2->csum.checksum)
continue;
csum_patched++;
csum_last = sym2;
}
/* Return the widest level that yields a unique (1:1) match */
if (name_orig == 1 && name_patched == 1)
match = name_last;
else if (scope_orig == 1 && scope_patched == 1)
match = scope_last;
else if (file_orig == 1 && file_patched == 1)
match = file_last;
else if (csum_orig == 1 && csum_patched == 1)
match = csum_last;
if (!match)
return NULL;
if (name_orig != 1 || name_patched != 1)
dbg_correlate("find_twin(): %s%s -> %s%s",
sym1->name, is_func_sym(sym1) ? "()" : "",
match->name, is_func_sym(match) ? "()" : "");
return match;
}
struct llvm_suffix_pair {
struct hlist_node hash;
const char *orig;
const char *patched;
};
static DECLARE_HASHTABLE(suffix_map, 7);
/*
* Build a mapping of known orig-to-patched LLVM suffixes based on
* already-correlated symbol pairs. All promoted symbols from the same TU
* share the same .llvm.<hash> suffix, so one correlated pair seeds the map
* for the entire TU.
*/
static int update_suffix_map(struct elf *elf)
{
struct llvm_suffix_pair *entry;
struct symbol *sym;
for_each_sym(elf, sym) {
const char *s1, *s2;
bool found;
if (!sym->twin)
continue;
s1 = llvm_suffix(sym->name);
s2 = llvm_suffix(sym->twin->name);
if (!s1 || !s2)
continue;
found = false;
hash_for_each_possible(suffix_map, entry, hash, str_hash(s1)) {
if (!strcmp(entry->orig, s1)) {
found = true;
break;
}
}
if (found)
continue;
entry = calloc(1, sizeof(*entry));
if (!entry) {
ERROR_GLIBC("calloc");
return -1;
}
entry->orig = s1;
entry->patched = s2;
hash_add(suffix_map, &entry->hash, str_hash(s1));
}
return 0;
}
/*
* Match by translating the symbol's .llvm.<hash> suffix through the suffix
* map to find the corresponding hash suffix for the patched object.
*
* Example: In the original kernel, TU drivers/base/core.c contains
* foo.llvm.12345 and bar.llvm.12345 (same TU, same hash). After patching,
* they become foo.llvm.67890 and bar.llvm.67890. If foo was already
* correlated by find_twin() (e.g., unique by name), the suffix map records
* .llvm.12345 -> .llvm.67890. When processing bar.llvm.12345, this
* function looks up .llvm.12345, gets .llvm.67890, constructs the name
* bar.llvm.67890, and finds the match.
*/
static struct symbol *find_twin_suffixed(struct elf *elf, struct symbol *sym1)
{
const char *suffix, *patched_suffix = NULL;
struct symbol *sym2, *match = NULL;
char name[SYM_NAME_LEN];
struct llvm_suffix_pair *entry;
int count = 0;
suffix = llvm_suffix(sym1->name);
if (!suffix)
return NULL;
hash_for_each_possible(suffix_map, entry, hash, str_hash(suffix)) {
if (!strcmp(entry->orig, suffix)) {
patched_suffix = entry->patched;
break;
}
}
if (!patched_suffix)
return NULL;
if (snprintf_check(name, SYM_NAME_LEN, "%s%s",
sym1->demangled_name, patched_suffix))
return NULL;
for_each_sym_by_name(elf, name, sym2) {
if (sym2->twin || sym1->type != sym2->type || sym2->dont_correlate)
continue;
count++;
match = sym2;
}
if (count != 1)
return NULL;
dbg_correlate("find_suffixed_twin(): %s%s -> %s%s",
sym1->name, is_func_sym(sym1) ? "()" : "",
match->name, is_func_sym(match) ? "()" : "");
return match;
}
/*
* Last-resort positional matching.
*
* Finds a symbol with the same position in the symbol table among
* same-demangled-name candidates, similar to livepatch sympos. Note that
* LLVM-promoted symbols are globals, which come after locals in the symbol
* table, so we have to be careful not to compare different scopes.
*
* Example: arch/x86/events/intel/core.c defines many __quirk variables via
* X86_MATCH_*() macros. In the symbol table they appear as __quirk.90,
* __quirk.97, __quirk.101, etc., all with demangled name __quirk, same
* scope, and same FILE symbol. No deterministic filter can distinguish
* them, so they're matched by position: the 1st __quirk in orig matches the
* 1st in patched, the 2nd matches the 2nd, etc.
*
* This is less deterministic than the other strategies, so it's done last.
*/
static struct symbol *find_twin_positional(struct elfs *e, struct symbol *sym1)
{
unsigned int idx_orig = 0, idx_patched = 0;
unsigned int sym1_pos = 0;
struct symbol *sym2, *match = NULL;
for_each_sym_by_demangled_name(e->orig, sym1->demangled_name, sym2) {
if (sym2->twin || sym1->type != sym2->type || sym2->dont_correlate ||
!maybe_same_file(sym1, sym2))
continue;
if (is_tu_local_sym(sym1) != is_tu_local_sym(sym2) ||
is_llvm_sym(sym1) != is_llvm_sym(sym2))
continue;
if (sym1 == sym2)
sym1_pos = idx_orig;
idx_orig++;
}
for_each_sym_by_demangled_name(e->patched, sym1->demangled_name, sym2) {
if (sym2->twin || sym1->type != sym2->type || sym2->dont_correlate ||
!maybe_same_file(sym1, sym2))
continue;
if (is_tu_local_sym(sym1) != is_tu_local_sym(sym2) ||
is_llvm_sym(sym1) != is_llvm_sym(sym2))
continue;
if (idx_patched == sym1_pos)
match = sym2;
idx_patched++;
}
if (idx_orig != idx_patched)
return NULL;
dbg_correlate("find_twin_positional(): %s%s -> %s%s",
sym1->name, is_func_sym(sym1) ? "()" : "",
match->name, is_func_sym(match) ? "()" : "");
return match;
}
/*
* Correlate symbols between the orig and patched objects. This is a
* prerequisite for detecting changed functions, as well as for properly
* translating relocations so they point to the correct symbol.
*/
static int correlate_symbols(struct elfs *e)
{
struct symbol *file1_sym, *file2_sym;
struct symbol *sym1, *sym2;
bool progress;
for_each_sym(e->orig, sym1)
sym1->dont_correlate = dont_correlate(sym1);
for_each_sym(e->patched, sym2)
sym2->dont_correlate = dont_correlate(sym2);
/* Correlate FILE symbols */
file1_sym = first_file_symbol(e->orig);
file2_sym = first_file_symbol(e->patched);
for (; ; file1_sym = next_file_symbol(e->orig, file1_sym),
file2_sym = next_file_symbol(e->patched, file2_sym)) {
if (!file1_sym && file2_sym) {
ERROR("FILE symbol mismatch: NULL != %s", file2_sym->name);
return -1;
}
if (file1_sym && !file2_sym) {
ERROR("FILE symbol mismatch: %s != NULL", file1_sym->name);
return -1;
}
if (!file1_sym)
break;
if (strcmp(file1_sym->name, file2_sym->name)) {
ERROR("FILE symbol mismatch: %s != %s", file1_sym->name, file2_sym->name);
return -1;
}
file1_sym->twin = file2_sym;
file2_sym->twin = file1_sym;
}
/*
* Correlate in two phases: loop deterministic levels until no more
* progress, then use positional fallback for the rest. This prevents
* the nondeterministic positional matching from stealing symbols that
* have deterministic matches.
*/
hash_init(suffix_map);
do {
progress = false;
for_each_sym(e->orig, sym1) {
if (sym1->twin || sym1->dont_correlate)
continue;
sym2 = find_twin(e, sym1);
if (!sym2)
continue;
sym1->twin = sym2;
sym2->twin = sym1;
progress = true;
}
if (update_suffix_map(e->orig))
return -1;
for_each_sym(e->orig, sym1) {
if (sym1->twin || sym1->dont_correlate)
continue;
sym2 = find_twin_suffixed(e->patched, sym1);
if (!sym2)
continue;
sym1->twin = sym2;
sym2->twin = sym1;
progress = true;
}
} while (progress);
for_each_sym(e->orig, sym1) {
if (sym1->twin || sym1->dont_correlate)
continue;
sym2 = find_twin_positional(e, sym1);
if (!sym2)
continue;
sym1->twin = sym2;
sym2->twin = sym1;
}
for_each_sym(e->orig, sym1) {
if (sym1->twin || sym1->dont_correlate)
continue;
WARN("no correlation: %s", sym1->name);
}
return 0;
}
/* "sympos" is used by livepatch to disambiguate duplicate symbol names */
static unsigned long find_sympos(struct elf *elf, struct symbol *sym)
{
bool vmlinux = str_ends_with(objname, "vmlinux.o");
unsigned long sympos = 0, nr_matches = 0;
bool has_dup = false;
struct symbol *s;
if (sym->bind != STB_LOCAL)
return 0;
if (vmlinux && is_func_sym(sym)) {
/*
* HACK: Unfortunately, symbol ordering can differ between
* vmlinux.o and vmlinux due to the linker script emitting
* .text.unlikely* before .text*. Count .text.unlikely* first.
*
* TODO: Disambiguate symbols more reliably (checksums?)
*/
for_each_sym(elf, s) {
if (strstarts(s->sec->name, ".text.unlikely") &&
!strcmp(s->name, sym->name)) {
nr_matches++;
if (s == sym)
sympos = nr_matches;
else
has_dup = true;
}
}
for_each_sym(elf, s) {
if (!strstarts(s->sec->name, ".text.unlikely") &&
!strcmp(s->name, sym->name)) {
nr_matches++;
if (s == sym)
sympos = nr_matches;
else
has_dup = true;
}
}
} else {
for_each_sym(elf, s) {
if (!strcmp(s->name, sym->name)) {
nr_matches++;
if (s == sym)
sympos = nr_matches;
else
has_dup = true;
}
}
}
if (!sympos) {
ERROR("can't find sympos for %s", sym->name);
return ULONG_MAX;
}
return has_dup ? sympos : 0;
}
static int clone_sym_relocs(struct elfs *e, struct symbol *patched_sym);
static struct symbol *__clone_symbol(struct elf *elf, struct symbol *patched_sym,
bool data_too)
{
struct section *out_sec = NULL;
unsigned long offset = 0;
struct symbol *out_sym;
if (data_too && !is_undef_sym(patched_sym)) {
struct section *patched_sec = patched_sym->sec;
out_sec = find_section_by_name(elf, patched_sec->name);
if (!out_sec) {
out_sec = elf_create_section(elf, patched_sec->name, 0,
patched_sec->sh.sh_entsize,
patched_sec->sh.sh_type,
patched_sec->sh.sh_addralign,
patched_sec->sh.sh_flags);
if (!out_sec)
return NULL;
}
if (is_string_sec(patched_sym->sec)) {
out_sym = elf_create_section_symbol(elf, out_sec);
if (!out_sym)
return NULL;
goto sym_created;
}
if (!is_sec_sym(patched_sym))
offset = ALIGN(sec_size(out_sec), out_sec->sh.sh_addralign);
if (patched_sym->len || is_sec_sym(patched_sym)) {
void *data = NULL;
size_t size;
/* bss doesn't have data */
if (patched_sym->sec->data && patched_sym->sec->data->d_buf)
data = patched_sym->sec->data->d_buf + patched_sym->offset;
if (is_sec_sym(patched_sym))
size = sec_size(patched_sym->sec);
else
size = patched_sym->len;
if (!elf_add_data(elf, out_sec, data, size))
return NULL;
}
}
out_sym = elf_create_symbol(elf, patched_sym->name, out_sec,
patched_sym->bind, patched_sym->type,
offset, patched_sym->len);
if (!out_sym)
return NULL;
sym_created:
patched_sym->clone = out_sym;
out_sym->clone = patched_sym;
return out_sym;
}
static const char *sym_type(struct symbol *sym)
{
switch (sym->type) {
case STT_NOTYPE: return "NOTYPE";
case STT_OBJECT: return "OBJECT";
case STT_FUNC: return "FUNC";
case STT_SECTION: return "SECTION";
case STT_FILE: return "FILE";