+++ /dev/null
->From a57cd35acf26ba6202ed6534a57f496464f431a1 Mon Sep 17 00:00:00 2001
-From: Szabolcs Nagy <nsz@port70.net>
-Date: Sat, 10 Aug 2019 23:14:40 +0000
-Subject: [PATCH] make relocation time symbol lookup and dlsym consistent
-
-Using common code path for all symbol lookups fixes three dlsym issues:
-
-- st_shndx of STT_TLS symbols were not checked and thus an undefined
- tls symbol reference could be incorrectly treated as a definition
- (the sysv hash lookup returns undefined symbols, gnu does not, so should
- be rare in practice).
-
-- symbol binding was not checked so a hidden symbol may be returned
- (in principle STB_LOCAL symbols may appear in the dynamic symbol table
- for hidden symbols, but linkers most likely don't produce it).
-
-- mips specific behaviour was not applied (ARCH_SYM_REJECT_UND) so
- undefined symbols may be returned on mips.
-
-always_inline is used to avoid relocation performance regression, the
-code generation for find_sym should not be affected.
----
- ldso/dynlink.c | 84 +++++++++++++++++++-------------------------------
- 1 file changed, 31 insertions(+), 53 deletions(-)
-
---- a/ldso/dynlink.c
-+++ b/ldso/dynlink.c
-@@ -283,12 +283,16 @@ static Sym *gnu_lookup_filtered(uint32_t
- #define ARCH_SYM_REJECT_UND(s) 0
- #endif
-
--static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
-+#if defined(__GNUC__)
-+__attribute__((always_inline))
-+#endif
-+static inline struct symdef find_sym2(struct dso *dso, const char *s, int need_def, int use_deps)
- {
- uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
- size_t ghm = 1ul << gh % (8*sizeof(size_t));
- struct symdef def = {0};
-- for (; dso; dso=dso->syms_next) {
-+ struct dso **deps = use_deps ? dso->deps : 0;
-+ for (; dso; dso=use_deps ? *deps++ : dso->syms_next) {
- Sym *sym;
- if ((ght = dso->ghashtab)) {
- sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
-@@ -313,6 +317,11 @@ static struct symdef find_sym(struct dso
- return def;
- }
-
-+static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
-+{
-+ return find_sym2(dso, s, need_def, 0);
-+}
-+
- static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
- {
- unsigned char *base = dso->base;
-@@ -2118,58 +2127,27 @@ static void *addr2dso(size_t a)
-
- static void *do_dlsym(struct dso *p, const char *s, void *ra)
- {
-- size_t i;
-- uint32_t h = 0, gh = 0, *ght;
-- Sym *sym;
-- if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
-- if (p == RTLD_DEFAULT) {
-- p = head;
-- } else if (p == RTLD_NEXT) {
-- p = addr2dso((size_t)ra);
-- if (!p) p=head;
-- p = p->next;
-- }
-- struct symdef def = find_sym(p, s, 0);
-- if (!def.sym) goto failed;
-- if ((def.sym->st_info&0xf) == STT_TLS)
-- return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
-- if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
-- return def.dso->funcdescs + (def.sym - def.dso->syms);
-- return laddr(def.dso, def.sym->st_value);
-- }
-- if (__dl_invalid_handle(p))
-+ int use_deps = 0;
-+ if (p == head || p == RTLD_DEFAULT) {
-+ p = head;
-+ } else if (p == RTLD_NEXT) {
-+ p = addr2dso((size_t)ra);
-+ if (!p) p=head;
-+ p = p->next;
-+ } else if (__dl_invalid_handle(p)) {
-+ return 0;
-+ } else
-+ use_deps = 1;
-+ struct symdef def = find_sym2(p, s, 0, use_deps);
-+ if (!def.sym) {
-+ error("Symbol not found: %s", s);
- return 0;
-- if ((ght = p->ghashtab)) {
-- gh = gnu_hash(s);
-- sym = gnu_lookup(gh, ght, p, s);
-- } else {
-- h = sysv_hash(s);
-- sym = sysv_lookup(s, h, p);
-- }
-- if (sym && (sym->st_info&0xf) == STT_TLS)
-- return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value-DTP_OFFSET});
-- if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
-- return p->funcdescs + (sym - p->syms);
-- if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
-- return laddr(p, sym->st_value);
-- for (i=0; p->deps[i]; i++) {
-- if ((ght = p->deps[i]->ghashtab)) {
-- if (!gh) gh = gnu_hash(s);
-- sym = gnu_lookup(gh, ght, p->deps[i], s);
-- } else {
-- if (!h) h = sysv_hash(s);
-- sym = sysv_lookup(s, h, p->deps[i]);
-- }
-- if (sym && (sym->st_info&0xf) == STT_TLS)
-- return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value-DTP_OFFSET});
-- if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
-- return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
-- if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
-- return laddr(p->deps[i], sym->st_value);
- }
--failed:
-- error("Symbol not found: %s", s);
-- return 0;
-+ if ((def.sym->st_info&0xf) == STT_TLS)
-+ return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
-+ if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
-+ return def.dso->funcdescs + (def.sym - def.dso->syms);
-+ return laddr(def.dso, def.sym->st_value);
- }
-
- int dladdr(const void *addr_arg, Dl_info *info)
projects / openwrt / staging / chunkeey.git / blobdiff