diff --git a/include/dlfcn.h b/include/dlfcn.h index dea74c7..8524e0b 100644 --- a/include/dlfcn.h +++ b/include/dlfcn.h @@ -18,6 +18,17 @@ char *dlerror(void); void *dlopen(const char *, int); void *dlsym(void *, const char *); +#ifdef _GNU_SOURCE +typedef struct { + const char *dli_fname; + void *dli_fbase; + const char *dli_sname; + void *dli_saddr; +} Dl_info; + +int dladdr (void *addr, Dl_info *info); +#endif + #ifdef __cplusplus } #endif diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index f55c6f1..d63da1c 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -1,3 +1,4 @@ +#define _GNU_SOURCE #include #include #include @@ -28,14 +29,20 @@ typedef Elf32_Phdr Phdr; typedef Elf32_Sym Sym; #define R_TYPE(x) ((x)&255) #define R_SYM(x) ((x)>>8) +#define ELF_ST_TYPE ELF32_ST_TYPE #else typedef Elf64_Ehdr Ehdr; typedef Elf64_Phdr Phdr; typedef Elf64_Sym Sym; #define R_TYPE(x) ((x)&0xffffffff) #define R_SYM(x) ((x)>>32) +#define ELF_ST_TYPE ELF64_ST_TYPE #endif +#define SYSV_HASH 0 +#define GNU_HASH 1 +#define NHASH 2 + struct debug { int ver; void *head; @@ -53,6 +60,7 @@ struct dso { int refcnt; Sym *syms; uint32_t *hashtab; + uint32_t *ghashtab; char *strings; unsigned char *map; size_t map_len; @@ -85,16 +93,27 @@ struct debug *_dl_debug_addr = &debug; #define AUX_CNT 24 #define DYN_CNT 34 -static void decode_vec(size_t *v, size_t *a, size_t cnt) +struct tag_range { + size_t start; + size_t size; +}; + +static void decode_vec(size_t *v, const struct tag_range *defs, size_t **storages, size_t defsize) { - memset(a, 0, cnt*sizeof(size_t)); - for (; v[0]; v+=2) if (v[0]defs[i].start && v[0]<=defs[i].start+defs[i].size) { + storages[i][0] |= 1ULL<syms; @@ -118,20 +146,86 @@ static Sym *lookup(const char *s, uint32_t h, struct dso *dso) return 0; } +static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso) +{ + size_t i; + Sym *sym; + char *strings = dso->strings; + uint32_t *hashtab = dso->ghashtab; + uint32_t nbuckets = hashtab[0]; + size_t *maskwords = (size_t *)(hashtab + 4); + uint32_t *buckets = hashtab + 4 + (hashtab[2]*(sizeof(size_t)/sizeof(uint32_t))); + uint32_t symndx = hashtab[1]; + Sym *syms = dso->syms; + uint32_t shift2 = hashtab[3]; + uint32_t h2 = h1 >> shift2; + uint32_t *hashvals = buckets + nbuckets; + uint32_t *hashval; + size_t c = sizeof(size_t) * 8; + size_t n = (h1/c) & (hashtab[2]-1); + size_t bitmask = (1 << (h1%c)) | (1 << (h2%c)); + + if ((maskwords[n] & bitmask) != bitmask) + return 0; + + n = buckets[h1 % nbuckets]; + if (!n) + return 0; + + sym = syms + n; + hashval = hashvals + n - symndx; + + for (h1 &= (uint32_t)-2;; sym++) { + h2 = *hashval++; + if ((h1 == (h2 & ~1)) && !strcmp(s, strings + sym->st_name)) + return sym; + + if (h2 & 1) + break; + } + + return 0; +} + #define OK_TYPES (1<hashtab) { + h = sysv_hash(s); + precomptab = precomp[0]; + } else { + gh = gnu_hash(s); + precomptab = precomp[0]; + } + + if (h == precomptab[0] && !strcmp(s, "dlopen")) rtld_used = 1; + if (h == precomptab[1] && !strcmp(s, "dlsym")) rtld_used = 1; + if (h == precomptab[2] && !strcmp(s, "__stack_chk_fail")) ssp_used = 1; + for (; dso; dso=dso->next) { Sym *sym; + if (!dso->global) continue; - sym = lookup(s, h, dso); + + if (dso->hashtab && (h || !dso->ghashtab)) { + if (!h) + h = sysv_hash(s); + sym = sysv_lookup(s, h, dso); + } else { + if (!gh) + gh = gnu_hash(s); + sym = gnu_lookup(s, gh, dso); + } + if (sym && (!need_def || sym->st_shndx) && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES) && (1<<(sym->st_info>>4) & OK_BINDS)) { @@ -320,11 +414,18 @@ static int path_open(const char *name, const char *search, char *buf, size_t buf static void decode_dyn(struct dso *p) { - size_t dyn[DYN_CNT] = {0}; - decode_vec(p->dynv, dyn, DYN_CNT); - p->syms = (void *)(p->base + dyn[DT_SYMTAB]); - p->hashtab = (void *)(p->base + dyn[DT_HASH]); - p->strings = (void *)(p->base + dyn[DT_STRTAB]); + static const struct tag_range defs[2] = {{0, DYN_CNT}, {DT_ADDRRNGHI-DT_ADDRNUM, DT_ADDRNUM}}; + size_t dynbase[DYN_CNT] = {0}; + size_t dynaddr[DT_ADDRNUM+1] = {0}; + size_t *storage[2] = {dynbase, dynaddr}; + decode_vec (p->dynv, defs, storage, 2); + p->syms = (void *)(p->base + dynbase[DT_SYMTAB]); + p->strings = (void *)(p->base + dynbase[DT_STRTAB]); + if (dynbase[DT_HASH]) + p->hashtab = (void *)(p->base + dynbase[DT_HASH]); + if (dynaddr[DT_ADDRNUM-DT_ADDRTAGIDX(DT_GNU_HASH)]) + p->ghashtab = (void *)(p->base + dynaddr[DT_ADDRNUM-DT_ADDRTAGIDX(DT_GNU_HASH)]); + } static struct dso *load_library(const char *name) @@ -486,9 +587,11 @@ static void make_global(struct dso *p) static void reloc_all(struct dso *p) { size_t dyn[DYN_CNT] = {0}; + static const struct tag_range defs = {0, DYN_CNT}; + size_t *storage = dyn; for (; p; p=p->next) { if (p->relocated) continue; - decode_vec(p->dynv, dyn, DYN_CNT); + decode_vec(p->dynv, &defs, &storage, 1); #ifdef NEED_ARCH_RELOCS do_arch_relocs(p, head); #endif @@ -521,9 +624,11 @@ static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride) static void do_init_fini(struct dso *p) { size_t dyn[DYN_CNT] = {0}; + static const struct tag_range defs = {0, DYN_CNT}; + size_t *storage = dyn; for (; p; p=p->prev) { if (p->constructed) return; - decode_vec(p->dynv, dyn, DYN_CNT); + decode_vec(p->dynv, &defs, &storage, 1); if (dyn[0] & (1<base + dyn[DT_FINI])); if (dyn[0] & (1<map>p->map_len; p=p->next); if (!p) p=head; @@ -798,12 +906,29 @@ static void *do_dlsym(struct dso *p, const char *s, void *ra) if (!res) goto failed; return res; } - h = hash(s); - sym = lookup(s, h, p); + + if (p->hashtab) { + h = sysv_hash(s); + sym = sysv_lookup(s, h, p); + } else { + gh = gnu_hash(s); + sym = gnu_lookup(s, gh, p); + } + + if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) return p->base + sym->st_value; if (p->deps) for (i=0; p->deps[i]; i++) { - sym = lookup(s, h, p->deps[i]); + if (p->deps[i]->hashtab && (h || !p->deps[i]->ghashtab)) { + if (!h) + h = sysv_hash(s); + sym = sysv_lookup(s, h, p->deps[i]); + } else { + if (!gh) + gh = gnu_hash(s); + sym = gnu_lookup(s, h, p->deps[i]); + } + if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) return p->deps[i]->base + sym->st_value; } @@ -813,6 +938,97 @@ failed: return 0; } +struct sym_search { + void *addr; + Dl_info *info; +}; + +static int find_closest_sym (struct dso *dso, Sym *sym, struct sym_search *search) +{ + void *symaddr = dso->base + sym->st_value; + char *strings = dso->strings; + Dl_info *info = search->info; + void *addr = search->addr; + void *prevaddr = info->dli_saddr; + + if (sym->st_value == 0 && sym->st_shndx == SHN_UNDEF) + return 1; + + if (ELF_ST_TYPE(sym->st_info) == STT_TLS) + return 1; + + if (addr < symaddr) + return 1; + + if (prevaddr && (addr - symaddr) > (addr - prevaddr)) + return 1; + + info->dli_saddr = symaddr; + info->dli_sname = strings + sym->st_name; + + if (addr == symaddr) + return 0; + + return 1; + +} + +static int do_dladdr (void *addr, Dl_info *info) +{ + struct sym_search search; + struct dso *p; + memset (info, 0, sizeof (*info)); + search.info = info; + search.addr = addr; + for (p=head; p; p=p->next) { + if ((unsigned char *)addr >= p->map && (unsigned char *)addr < p->map + p->map_len) { + Sym *syms = p->syms; + uint32_t *hashtab; + size_t i; + info->dli_fname = p->name; + info->dli_fbase = p->base; + if (p->hashtab) { + hashtab = p->hashtab; + for (i = 0; i < hashtab[1]; i++) { + if (!find_closest_sym (p, syms + i, &search)) + return 1; + } + } else { + uint32_t *buckets; + uint32_t nbuckets; + uint32_t *hashvals; + uint32_t symndx; + hashtab = p->ghashtab; + buckets = hashtab + 4 + (hashtab[2] * (sizeof(size_t)/sizeof(uint32_t))); + nbuckets = hashtab[0]; + hashvals = buckets + nbuckets; + symndx = hashtab[1]; + for (i = 0; i < nbuckets; ++i) { + uint32_t n = buckets[i]; + Sym *sym = syms + n; + uint32_t *hashval = hashvals + n - symndx; + + do { + if (!find_closest_sym (p, sym, &search)) + return 1; + }while (!(*hashval++ & 1)); + } + } + return 1; + } + } + return 0; +} + +int dladdr (void *addr, Dl_info *info) +{ + int res; + pthread_rwlock_rdlock(&lock); + res = do_dladdr (addr, info); + pthread_rwlock_unlock(&lock); + return res; +} + void *__dlsym(void *p, const char *s, void *ra) { void *res;