X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fldso%2Fdynlink.c;h=f2bcd0f3d401e8dca13178d3b1a8dba64866dd0d;hb=dcd60371500a74d489372cac7240674c992c2484;hp=774ab84922283a6feb5838d9a6720ee2dde7ad6f;hpb=9b153c043ea486d28f96a7e01419f650fe0e1b26;p=musl diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index 774ab849..f2bcd0f3 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -68,11 +68,19 @@ struct dso { char constructed; struct dso **deps; void *tls_image; - size_t tls_len, tls_size, tls_align, tls_id; + size_t tls_len, tls_size, tls_align, tls_id, tls_offset; + void **new_dtv; + unsigned char *new_tls; + int new_dtv_idx, new_tls_idx; char *shortname; char buf[]; }; +struct symdef { + Sym *sym; + struct dso *dso; +}; + #include "reloc.h" void __init_ssp(size_t *); @@ -80,7 +88,6 @@ void *__install_initial_tls(void *); static struct dso *head, *tail, *libc; static char *env_path, *sys_path, *r_path; -static int rtld_used; static int ssp_used; static int runtime; static int ldd_mode; @@ -173,22 +180,18 @@ static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso) return 0; } -#define OK_TYPES (1<ghashtab) { gh = gnu_hash(s); - if (gh == 0xf9040207 && !strcmp(s, "dlopen")) rtld_used = 1; - if (gh == 0xf4dc4ae && !strcmp(s, "dlsym")) rtld_used = 1; if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1; } else { h = sysv_hash(s); - if (h == 0x6b366be && !strcmp(s, "dlopen")) rtld_used = 1; - if (h == 0x6b3afd && !strcmp(s, "dlsym")) rtld_used = 1; if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1; } for (; dso; dso=dso->next) { @@ -204,8 +207,9 @@ static void *find_sym(struct dso *dso, const char *s, int need_def) if (sym && (!need_def || sym->st_shndx) && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES) && (1<<(sym->st_info>>4) & OK_BINDS)) { - if (def && sym->st_info>>4 == STB_WEAK) continue; - def = dso->base + sym->st_value; + if (def.sym && sym->st_info>>4 == STB_WEAK) continue; + def.sym = sym; + def.dso = dso; if (sym->st_info>>4 == STB_GLOBAL) break; } } @@ -219,22 +223,20 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri char *strings = dso->strings; Sym *sym; const char *name; - size_t sym_val, sym_size; - size_t *reloc_addr; void *ctx; int type; int sym_index; + struct symdef def; for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) { - reloc_addr = (void *)(base + rel[0]); type = R_TYPE(rel[1]); sym_index = R_SYM(rel[1]); if (sym_index) { sym = syms + sym_index; name = strings + sym->st_name; ctx = IS_COPY(type) ? head->next : head; - sym_val = (size_t)find_sym(ctx, name, IS_PLT(type)); - if (!sym_val && sym->st_info>>4 != STB_WEAK) { + def = find_sym(ctx, name, IS_PLT(type)); + if (!def.sym && sym->st_info>>4 != STB_WEAK) { snprintf(errbuf, sizeof errbuf, "Error relocating %s: %s: symbol not found", dso->name, name); @@ -243,11 +245,14 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri ldso_fail = 1; continue; } - sym_size = sym->st_size; } else { - sym_val = sym_size = 0; + sym = 0; + def.sym = 0; + def.dso = 0; } - do_single_reloc(reloc_addr, type, sym_val, sym_size, base, rel[2]); + do_single_reloc(dso, base, (void *)(base + rel[0]), type, + stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def, + def.sym?(size_t)(def.dso->base+def.sym->st_value):0); } } @@ -418,6 +423,8 @@ static struct dso *load_library(const char *name) struct dso *p, temp_dso = {0}; int fd; struct stat st; + size_t alloc_size; + int n_th = 0; /* Catch and block attempts to reload the implementation itself */ if (name[0]=='l' && name[1]=='i' && name[2]=='b') { @@ -485,18 +492,27 @@ static struct dso *load_library(const char *name) map = map_library(fd, &temp_dso); close(fd); if (!map) return 0; - p = malloc(sizeof *p + strlen(pathname) + 1); + + /* Allocate storage for the new DSO. When there is TLS, this + * storage must include a reservation for all pre-existing + * threads to obtain copies of both the new TLS, and an + * extended DTV capable of storing an additional slot for + * the newly-loaded DSO. */ + alloc_size = sizeof *p + strlen(pathname) + 1; + if (runtime && temp_dso.tls_image) { + size_t per_th = temp_dso.tls_size + temp_dso.tls_align + + sizeof(void *) * (tls_cnt+3); + n_th = __libc.threads_minus_1 + 1; + if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX; + else alloc_size += n_th * per_th; + } + p = calloc(1, alloc_size); if (!p) { munmap(map, map_len); return 0; } memcpy(p, &temp_dso, sizeof temp_dso); decode_dyn(p); - if (p->tls_image) { - p->tls_id = ++tls_cnt; - tls_size += p->tls_size + p->tls_align + 8*sizeof(size_t) - 1 - & -4*sizeof(size_t); - } p->dev = st.st_dev; p->ino = st.st_ino; p->refcnt = 1; @@ -504,6 +520,14 @@ static struct dso *load_library(const char *name) strcpy(p->name, pathname); /* Add a shortname only if name arg was not an explicit pathname. */ if (pathname != name) p->shortname = strrchr(p->name, '/')+1; + if (p->tls_image) { + p->tls_id = ++tls_cnt; + tls_size += p->tls_size + p->tls_align + 8*sizeof(size_t) - 1 + & -4*sizeof(size_t); + p->new_dtv = (void *)(-sizeof(size_t) & + (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t))); + p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1)); + } tail->next = p; p->prev = tail; @@ -635,14 +659,14 @@ void _dl_debug_state(void) { } -void *__copy_tls(unsigned char *mem, size_t cnt) +void *__copy_tls(unsigned char *mem) { struct dso *p; void **dtv = (void *)mem; - dtv[0] = (void *)cnt; - mem = (void *)(dtv + cnt + 1); + dtv[0] = (void *)tls_cnt; + mem = (void *)(dtv + tls_cnt + 1); for (p=tail; p; p=p->prev) { - if (p->tls_id-1 >= cnt) continue; + if (!p->tls_id) continue; mem += -p->tls_len & (4*sizeof(size_t)-1); mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1); @@ -654,14 +678,46 @@ void *__copy_tls(unsigned char *mem, size_t cnt) return mem; } -void *__tls_get_addr(size_t *p) +void *__tls_get_addr(size_t *v) { pthread_t self = __pthread_self(); - if ((size_t)self->dtv[0] < p[0]) { - // FIXME: obtain new DTV and TLS from the DSO - a_crash(); + if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) + return (char *)self->dtv[v[0]]+v[1]; + + /* Block signals to make accessing new TLS async-signal-safe */ + sigset_t set; + sigfillset(&set); + pthread_sigmask(SIG_BLOCK, &set, &set); + if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) { + pthread_sigmask(SIG_SETMASK, &set, 0); + return (char *)self->dtv[v[0]]+v[1]; + } + + /* This is safe without any locks held because, if the caller + * is able to request the Nth entry of the DTV, the DSO list + * must be valid at least that far out and it was synchronized + * at program startup or by an already-completed call to dlopen. */ + struct dso *p; + for (p=head; p->tls_id != v[0]; p=p->next); + + /* Get new DTV space from new DSO if needed */ + if (!self->dtv || v[0] > (size_t)self->dtv[0]) { + void **newdtv = p->new_dtv + + (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1); + if (self->dtv) memcpy(newdtv, self->dtv, + ((size_t)self->dtv[0]+1) * sizeof(void *)); + newdtv[0] = (void *)v[0]; + self->dtv = newdtv; } - return (char *)self->dtv[p[0]] + p[1]; + + /* Get new TLS memory from new DSO */ + unsigned char *mem = p->new_tls + + (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1); + mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1); + self->dtv[v[0]] = mem; + memcpy(mem, p->tls_image, p->tls_size); + pthread_sigmask(SIG_SETMASK, &set, 0); + return mem + v[1]; } void *__dynlink(int argc, char **argv) @@ -821,9 +877,37 @@ void *__dynlink(int argc, char **argv) if (env_preload) load_preload(env_preload); load_deps(app); make_global(app); + + /* Make an initial pass setting up TLS before performing relocs. + * This provides the TP-based offset of each DSO's TLS for + * use in TP-relative relocations. After relocations, we need + * to copy the TLS images again in case they had relocs. */ + tls_size += sizeof(struct pthread) + 4*sizeof(size_t); + __libc.tls_size = tls_size; + if (tls_cnt) { + struct dso *p; + void *mem = mmap(0, __libc.tls_size, PROT_READ|PROT_WRITE, + MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); + if (mem==MAP_FAILED || + !__install_initial_tls(__copy_tls(mem))) { + dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n", + argv[0], tls_size); + _exit(127); + } + for (p=head; p; p=p->next) { + if (!p->tls_id) continue; + p->tls_offset = (char *)__pthread_self() + - (char *)__pthread_self()->dtv[p->tls_id]; + } + } + reloc_all(app->next); reloc_all(app); + /* The initial DTV is located at the base of the memory + * allocated for TLS. Repeat copying TLS to pick up relocs. */ + if (tls_cnt) __copy_tls((void *)__pthread_self()->dtv); + if (ldso_fail) _exit(127); if (ldd_mode) _exit(0); @@ -845,36 +929,18 @@ void *__dynlink(int argc, char **argv) debug.state = 0; _dl_debug_state(); - tls_size += sizeof(struct pthread) + 4*sizeof(size_t); - __libc.tls_size = tls_size; - __libc.tls_cnt = tls_cnt; - if (tls_cnt) { - void *mem = mmap(0, __libc.tls_size, PROT_READ|PROT_WRITE, - MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); - if (mem==MAP_FAILED || - !__install_initial_tls(__copy_tls(mem, tls_cnt))) { - dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n", - argv[0], tls_size); - _exit(127); - } - } if (ssp_used) __init_ssp(auxv); do_init_fini(tail); - if (!rtld_used) { - free_all(head); - free(sys_path); - reclaim((void *)builtin_dsos, 0, sizeof builtin_dsos); - } - errno = 0; return (void *)aux[AT_ENTRY]; } void *dlopen(const char *file, int mode) { - struct dso *volatile p, *orig_tail = tail, *next; + struct dso *volatile p, *orig_tail, *next; + size_t orig_tls_cnt; size_t i; int cs; @@ -882,10 +948,15 @@ void *dlopen(const char *file, int mode) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); pthread_rwlock_wrlock(&lock); + __inhibit_ptc(); + + p = 0; + orig_tls_cnt = tls_cnt; + orig_tail = tail; if (setjmp(rtld_fail)) { /* Clean up anything new that was (partially) loaded */ - if (p->deps) for (i=0; p->deps[i]; i++) + if (p && p->deps) for (i=0; p->deps[i]; i++) if (p->deps[i]->global < 0) p->deps[i]->global = 0; for (p=orig_tail->next; p; p=next) { @@ -894,6 +965,8 @@ void *dlopen(const char *file, int mode) free(p->deps); free(p); } + tls_cnt = orig_tls_cnt; + tls_size = __libc.tls_size; tail = orig_tail; tail->next = 0; p = 0; @@ -928,12 +1001,15 @@ void *dlopen(const char *file, int mode) p->global = 1; } + __libc.tls_size = tls_size; + if (ssp_used) __init_ssp(auxv); _dl_debug_state(); do_init_fini(tail); end: + __release_ptc(); pthread_rwlock_unlock(&lock); pthread_setcancelstate(cs, 0); return p; @@ -944,17 +1020,14 @@ static void *do_dlsym(struct dso *p, const char *s, void *ra) size_t i; uint32_t h = 0, gh = 0; Sym *sym; - if (p == RTLD_NEXT) { - for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next); - if (!p) p=head; - void *res = find_sym(p->next, s, 0); - if (!res) goto failed; - return res; - } - if (p == head || p == RTLD_DEFAULT) { - void *res = find_sym(head, s, 0); - if (!res) goto failed; - return res; + if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) { + if (p == RTLD_NEXT) { + for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next); + if (!p) p=head; + } + struct symdef def = find_sym(p->next, s, 0); + if (!def.sym) goto failed; + return def.dso->base + def.sym->st_value; } if (p->ghashtab) { gh = gnu_hash(s);