diff options
Diffstat (limited to 'src/ldso')
| -rw-r--r-- | src/ldso/dynlink.c | 100 |
1 files changed, 81 insertions, 19 deletions
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index 2bbd492a..f2bcd0f3 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -69,6 +69,9 @@ struct dso { struct dso **deps; void *tls_image; 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[]; }; @@ -420,6 +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') { @@ -487,18 +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; @@ -506,6 +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; @@ -637,14 +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); @@ -656,14 +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) @@ -830,13 +884,12 @@ void *__dynlink(int argc, char **argv) * 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; - __libc.tls_cnt = tls_cnt; 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, tls_cnt))) { + !__install_initial_tls(__copy_tls(mem))) { dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n", argv[0], tls_size); _exit(127); @@ -853,7 +906,7 @@ void *__dynlink(int argc, char **argv) /* 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, tls_cnt); + if (tls_cnt) __copy_tls((void *)__pthread_self()->dtv); if (ldso_fail) _exit(127); if (ldd_mode) _exit(0); @@ -887,6 +940,7 @@ void *__dynlink(int argc, char **argv) void *dlopen(const char *file, int mode) { struct dso *volatile p, *orig_tail, *next; + size_t orig_tls_cnt; size_t i; int cs; @@ -894,12 +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) { @@ -908,6 +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; @@ -942,12 +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; |