diff options
Diffstat (limited to 'ldso/dynlink.c')
| -rw-r--r-- | ldso/dynlink.c | 775 |
1 files changed, 563 insertions, 212 deletions
diff --git a/ldso/dynlink.c b/ldso/dynlink.c index ec921dfd..324aa859 100644 --- a/ldso/dynlink.c +++ b/ldso/dynlink.c @@ -1,5 +1,5 @@ #define _GNU_SOURCE -#include <stdio.h> +#define SYSCALL_NO_TLS 1 #include <stdlib.h> #include <stdarg.h> #include <stddef.h> @@ -17,16 +17,34 @@ #include <pthread.h> #include <ctype.h> #include <dlfcn.h> +#include <semaphore.h> +#include <sys/membarrier.h> #include "pthread_impl.h" -#include "libc.h" +#include "fork_impl.h" #include "dynlink.h" -#include "malloc_impl.h" -static void error(const char *, ...); +static size_t ldso_page_size; +#ifndef PAGE_SIZE +#define PAGE_SIZE ldso_page_size +#endif + +#include "libc.h" + +#define malloc __libc_malloc +#define calloc __libc_calloc +#define realloc __libc_realloc +#define free __libc_free + +static void error_impl(const char *, ...); +static void error_noop(const char *, ...); +static void (*error)(const char *, ...) = error_noop; #define MAXP2(a,b) (-(-(a)&-(b))) #define ALIGN(x,y) ((x)+(y)-1 & -(y)) +#define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m))) +#define countof(a) ((sizeof (a))/(sizeof (a)[0])) + struct debug { int ver; void *head; @@ -67,14 +85,19 @@ struct dso { char relocated; char constructed; char kernel_mapped; + char mark; + char bfs_built; + char runtime_loaded; struct dso **deps, *needed_by; + size_t ndeps_direct; + size_t next_dep; + pthread_t ctor_visitor; char *rpath_orig, *rpath; struct tls_module tls; size_t tls_id; size_t relro_start, relro_end; uintptr_t *new_dtv; unsigned char *new_tls; - volatile int new_dtv_idx, new_tls_idx; struct td_index *td_index; struct dso *fini_next; char *shortname; @@ -96,6 +119,8 @@ struct symdef { struct dso *dso; }; +typedef void (*stage3_func)(size_t *, size_t *); + static struct builtin_tls { char c; struct pthread pt; @@ -114,19 +139,26 @@ static int runtime; static int ldd_mode; static int ldso_fail; static int noload; +static int shutting_down; static jmp_buf *rtld_fail; static pthread_rwlock_t lock; static struct debug debug; static struct tls_module *tls_tail; static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN; static size_t static_tls_cnt; -static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE }; +static pthread_mutex_t init_fini_lock; +static pthread_cond_t ctor_cond; +static struct dso *builtin_deps[2]; +static struct dso *const no_deps[1]; +static struct dso *builtin_ctor_queue[4]; +static struct dso **main_ctor_queue; static struct fdpic_loadmap *app_loadmap; static struct fdpic_dummy_loadmap app_dummy_loadmap; -static struct dso *const nodeps_dummy; struct debug *_dl_debug_addr = &debug; +extern weak hidden char __ehdr_start[]; + extern hidden int __malloc_replaced; hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0; @@ -167,8 +199,14 @@ static void *laddr_pg(const struct dso *p, size_t v) } return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr); } -#define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \ - laddr(p, v), (p)->got }) +static void (*fdbarrier(void *p))() +{ + void (*fd)(); + __asm__("" : "=r"(fd) : "0"(p)); + return fd; +} +#define fpaddr(p, v) fdbarrier((&(struct funcdesc){ \ + laddr(p, v), (p)->got })) #else #define laddr(p, v) (void *)((p)->base + (v)) #define laddr_pg(p, v) laddr(p, v) @@ -180,7 +218,8 @@ static void decode_vec(size_t *v, size_t *a, size_t cnt) size_t i; for (i=0; i<cnt; i++) a[i] = 0; for (; v[0]; v+=2) if (v[0]-1<cnt-1) { - a[0] |= 1UL<<v[0]; + if (v[0] < 8*sizeof(long)) + a[0] |= 1UL<<v[0]; a[v[0]] = v[1]; } } @@ -267,12 +306,16 @@ static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, #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); @@ -297,6 +340,45 @@ static struct symdef find_sym(struct dso *dso, const char *s, int need_def) 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 struct symdef get_lfs64(const char *name) +{ + const char *p; + static const char lfs64_list[] = + "aio_cancel\0aio_error\0aio_fsync\0aio_read\0aio_return\0" + "aio_suspend\0aio_write\0alphasort\0creat\0fallocate\0" + "fgetpos\0fopen\0freopen\0fseeko\0fsetpos\0fstat\0" + "fstatat\0fstatfs\0fstatvfs\0ftello\0ftruncate\0ftw\0" + "getdents\0getrlimit\0glob\0globfree\0lio_listio\0" + "lockf\0lseek\0lstat\0mkostemp\0mkostemps\0mkstemp\0" + "mkstemps\0mmap\0nftw\0open\0openat\0posix_fadvise\0" + "posix_fallocate\0pread\0preadv\0prlimit\0pwrite\0" + "pwritev\0readdir\0scandir\0sendfile\0setrlimit\0" + "stat\0statfs\0statvfs\0tmpfile\0truncate\0versionsort\0" + "__fxstat\0__fxstatat\0__lxstat\0__xstat\0"; + size_t l; + char buf[16]; + for (l=0; name[l]; l++) { + if (l >= sizeof buf) goto nomatch; + buf[l] = name[l]; + } + if (!strcmp(name, "readdir64_r")) + return find_sym(&ldso, "readdir_r", 1); + if (l<2 || name[l-2]!='6' || name[l-1]!='4') + goto nomatch; + buf[l-=2] = 0; + for (p=lfs64_list; *p; p++) { + if (!strcmp(buf, p)) return find_sym(&ldso, buf, 1); + while (*p) p++; + } +nomatch: + return (struct symdef){ 0 }; +} + static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride) { unsigned char *base = dso->base; @@ -347,9 +429,10 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri sym = syms + sym_index; name = strings + sym->st_name; ctx = type==REL_COPY ? head->syms_next : head; - def = (sym->st_info&0xf) == STT_SECTION + def = (sym->st_info>>4) == STB_LOCAL ? (struct symdef){ .dso = dso, .sym = sym } : find_sym(ctx, name, type==REL_PLT); + if (!def.sym) def = get_lfs64(name); if (!def.sym && (sym->st_shndx != SHN_UNDEF || sym->st_info>>4 != STB_WEAK)) { if (dso->lazy && (type==REL_PLT || type==REL_GOT)) { @@ -374,7 +457,7 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri tls_val = def.sym ? def.sym->st_value : 0; if ((type == REL_TPOFF || type == REL_TPOFF_NEG) - && runtime && def.dso->tls_id > static_tls_cnt) { + && def.dso->tls_id > static_tls_cnt) { error("Error relocating %s: %s: initial-exec TLS " "resolves to dynamic definition in %s", dso->name, name, def.dso->name); @@ -382,8 +465,6 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri } switch(type) { - case REL_NONE: - break; case REL_OFFSET: addend -= (size_t)reloc_addr; case REL_SYMBOLIC: @@ -391,6 +472,9 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri case REL_PLT: *reloc_addr = sym_val + addend; break; + case REL_USYMBOLIC: + memcpy(reloc_addr, &(size_t){sym_val + addend}, sizeof(size_t)); + break; case REL_RELATIVE: *reloc_addr = (size_t)base + addend; break; @@ -433,8 +517,8 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri break; #endif case REL_TLSDESC: - if (stride<3) addend = reloc_addr[1]; - if (runtime && def.dso->tls_id > static_tls_cnt) { + if (stride<3) addend = reloc_addr[!TLSDESC_BACKWARDS]; + if (def.dso->tls_id > static_tls_cnt) { struct td_index *new = malloc(sizeof *new); if (!new) { error( @@ -458,13 +542,13 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri + addend; #endif } -#ifdef TLSDESC_BACKWARDS /* Some archs (32-bit ARM at least) invert the order of * the descriptor members. Fix them up here. */ - size_t tmp = reloc_addr[0]; - reloc_addr[0] = reloc_addr[1]; - reloc_addr[1] = tmp; -#endif + if (TLSDESC_BACKWARDS) { + size_t tmp = reloc_addr[0]; + reloc_addr[0] = reloc_addr[1]; + reloc_addr[1] = tmp; + } break; default: error("Error relocating %s: unsupported relocation type %d", @@ -475,6 +559,24 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri } } +static void do_relr_relocs(struct dso *dso, size_t *relr, size_t relr_size) +{ + if (dso == &ldso) return; /* self-relocation was done in _dlstart */ + unsigned char *base = dso->base; + size_t *reloc_addr; + for (; relr_size; relr++, relr_size-=sizeof(size_t)) + if ((relr[0]&1) == 0) { + reloc_addr = laddr(dso, relr[0]); + *reloc_addr++ += (size_t)base; + } else { + int i = 0; + for (size_t bitmap=relr[0]; (bitmap>>=1); i++) + if (bitmap&1) + reloc_addr[i] += (size_t)base; + reloc_addr += 8*sizeof(size_t)-1; + } +} + static void redo_lazy_relocs() { struct dso *p = lazy_head, *next; @@ -523,10 +625,25 @@ static void reclaim_gaps(struct dso *dso) } } +static ssize_t read_loop(int fd, void *p, size_t n) +{ + for (size_t i=0; i<n; ) { + ssize_t l = read(fd, (char *)p+i, n-i); + if (l<0) { + if (errno==EINTR) continue; + else return -1; + } + if (l==0) return i; + i += l; + } + return n; +} + static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off) { static int no_map_fixed; char *q; + if (!n) return p; if (!no_map_fixed) { q = mmap(p, n, prot, flags|MAP_FIXED, fd, off); if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL) @@ -813,7 +930,7 @@ static int fixup_rpath(struct dso *p, char *buf, size_t buf_size) case ENOENT: case ENOTDIR: case EACCES: - break; + return 0; default: return -1; } @@ -904,7 +1021,7 @@ static void *dl_mmap(size_t n) #else p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0); #endif - return p == MAP_FAILED ? 0 : p; + return (unsigned long)p > -4096UL ? 0 : p; } static void makefuncdescs(struct dso *p) @@ -1027,13 +1144,17 @@ static struct dso *load_library(const char *name, struct dso *needed_by) snprintf(etc_ldso_path, sizeof etc_ldso_path, "%.*s/etc/ld-musl-" LDSO_ARCH ".path", (int)prefix_len, prefix); - FILE *f = fopen(etc_ldso_path, "rbe"); - if (f) { - if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) { + fd = open(etc_ldso_path, O_RDONLY|O_CLOEXEC); + if (fd>=0) { + size_t n = 0; + if (!fstat(fd, &st)) n = st.st_size; + if ((sys_path = malloc(n+1))) + sys_path[n] = 0; + if (!sys_path || read_loop(fd, sys_path, n)<0) { free(sys_path); sys_path = ""; } - fclose(f); + close(fd); } else if (errno != ENOENT) { sys_path = ""; } @@ -1101,6 +1222,7 @@ static struct dso *load_library(const char *name, struct dso *needed_by) p->ino = st.st_ino; p->needed_by = needed_by; p->name = p->buf; + p->runtime_loaded = runtime; 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; @@ -1108,9 +1230,9 @@ static struct dso *load_library(const char *name, struct dso *needed_by) p->tls_id = ++tls_cnt; tls_align = MAXP2(tls_align, p->tls.align); #ifdef TLS_ABOVE_TP - p->tls.offset = tls_offset + ( (tls_align-1) & - -(tls_offset + (uintptr_t)p->tls.image) ); - tls_offset += p->tls.size; + p->tls.offset = tls_offset + ( (p->tls.align-1) & + (-tls_offset + (uintptr_t)p->tls.image) ); + tls_offset = p->tls.offset + p->tls.size; #else tls_offset += p->tls.size + p->tls.align - 1; tls_offset -= (tls_offset + (uintptr_t)p->tls.image) @@ -1136,30 +1258,99 @@ static struct dso *load_library(const char *name, struct dso *needed_by) return p; } +static void load_direct_deps(struct dso *p) +{ + size_t i, cnt=0; + + if (p->deps) return; + /* For head, all preloads are direct pseudo-dependencies. + * Count and include them now to avoid realloc later. */ + if (p==head) for (struct dso *q=p->next; q; q=q->next) + cnt++; + for (i=0; p->dynv[i]; i+=2) + if (p->dynv[i] == DT_NEEDED) cnt++; + /* Use builtin buffer for apps with no external deps, to + * preserve property of no runtime failure paths. */ + p->deps = (p==head && cnt<2) ? builtin_deps : + calloc(cnt+1, sizeof *p->deps); + if (!p->deps) { + error("Error loading dependencies for %s", p->name); + if (runtime) longjmp(*rtld_fail, 1); + } + cnt=0; + if (p==head) for (struct dso *q=p->next; q; q=q->next) + p->deps[cnt++] = q; + for (i=0; p->dynv[i]; i+=2) { + if (p->dynv[i] != DT_NEEDED) continue; + struct dso *dep = load_library(p->strings + p->dynv[i+1], p); + if (!dep) { + error("Error loading shared library %s: %m (needed by %s)", + p->strings + p->dynv[i+1], p->name); + if (runtime) longjmp(*rtld_fail, 1); + continue; + } + p->deps[cnt++] = dep; + } + p->deps[cnt] = 0; + p->ndeps_direct = cnt; +} + static void load_deps(struct dso *p) { - size_t i, ndeps=0; - struct dso ***deps = &p->deps, **tmp, *dep; - for (; p; p=p->next) { - for (i=0; p->dynv[i]; i+=2) { - if (p->dynv[i] != DT_NEEDED) continue; - dep = load_library(p->strings + p->dynv[i+1], p); - if (!dep) { - error("Error loading shared library %s: %m (needed by %s)", - p->strings + p->dynv[i+1], p->name); - if (runtime) longjmp(*rtld_fail, 1); - continue; - } - if (runtime) { - tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2)); - if (!tmp) longjmp(*rtld_fail, 1); - tmp[ndeps++] = dep; - tmp[ndeps] = 0; - *deps = tmp; - } + if (p->deps) return; + for (; p; p=p->next) + load_direct_deps(p); +} + +static void extend_bfs_deps(struct dso *p) +{ + size_t i, j, cnt, ndeps_all; + struct dso **tmp; + + /* Can't use realloc if the original p->deps was allocated at + * program entry and malloc has been replaced, or if it's + * the builtin non-allocated trivial main program deps array. */ + int no_realloc = (__malloc_replaced && !p->runtime_loaded) + || p->deps == builtin_deps; + + if (p->bfs_built) return; + ndeps_all = p->ndeps_direct; + + /* Mark existing (direct) deps so they won't be duplicated. */ + for (i=0; p->deps[i]; i++) + p->deps[i]->mark = 1; + + /* For each dependency already in the list, copy its list of direct + * dependencies to the list, excluding any items already in the + * list. Note that the list this loop iterates over will grow during + * the loop, but since duplicates are excluded, growth is bounded. */ + for (i=0; p->deps[i]; i++) { + struct dso *dep = p->deps[i]; + for (j=cnt=0; j<dep->ndeps_direct; j++) + if (!dep->deps[j]->mark) cnt++; + tmp = no_realloc ? + malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) : + realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1)); + if (!tmp) { + error("Error recording dependencies for %s", p->name); + if (runtime) longjmp(*rtld_fail, 1); + continue; + } + if (no_realloc) { + memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1)); + no_realloc = 0; + } + p->deps = tmp; + for (j=0; j<dep->ndeps_direct; j++) { + if (dep->deps[j]->mark) continue; + dep->deps[j]->mark = 1; + p->deps[ndeps_all++] = dep->deps[j]; } + p->deps[ndeps_all] = 0; } - if (!*deps) *deps = (struct dso **)&nodeps_dummy; + p->bfs_built = 1; + for (p=head; p; p=p->next) + p->mark = 0; } static void load_preload(char *s) @@ -1228,13 +1419,17 @@ static void reloc_all(struct dso *p) 2+(dyn[DT_PLTREL]==DT_RELA)); do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2); do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3); - - if (head != &ldso && p->relro_start != p->relro_end && - mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ) - && errno != ENOSYS) { - error("Error relocating %s: RELRO protection failed: %m", - p->name); - if (runtime) longjmp(*rtld_fail, 1); + if (!DL_FDPIC) + do_relr_relocs(p, laddr(p, dyn[DT_RELR]), dyn[DT_RELRSZ]); + + if (head != &ldso && p->relro_start != p->relro_end) { + long ret = __syscall(SYS_mprotect, laddr(p, p->relro_start), + p->relro_end-p->relro_start, PROT_READ); + if (ret != 0 && ret != -ENOSYS) { + error("Error relocating %s: RELRO protection failed: %m", + p->name); + if (runtime) longjmp(*rtld_fail, 1); + } } p->relocated = 1; @@ -1275,7 +1470,18 @@ void __libc_exit_fini() { struct dso *p; size_t dyn[DYN_CNT]; + pthread_t self = __pthread_self(); + + /* Take both locks before setting shutting_down, so that + * either lock is sufficient to read its value. The lock + * order matches that in dlopen to avoid deadlock. */ + pthread_rwlock_wrlock(&lock); + pthread_mutex_lock(&init_fini_lock); + shutting_down = 1; + pthread_rwlock_unlock(&lock); for (p=fini_head; p; p=p->fini_next) { + while (p->ctor_visitor && p->ctor_visitor!=self) + pthread_cond_wait(&ctor_cond, &init_fini_lock); if (!p->constructed) continue; decode_vec(p->dynv, dyn, DYN_CNT); if (dyn[0] & (1<<DT_FINI_ARRAY)) { @@ -1290,22 +1496,108 @@ void __libc_exit_fini() } } -static void do_init_fini(struct dso *p) +void __ldso_atfork(int who) { - size_t dyn[DYN_CNT]; - int need_locking = libc.threads_minus_1; - /* Allow recursive calls that arise when a library calls - * dlopen from one of its constructors, but block any - * other threads until all ctors have finished. */ - if (need_locking) pthread_mutex_lock(&init_fini_lock); - for (; p; p=p->prev) { - if (p->constructed) continue; - p->constructed = 1; + if (who<0) { + pthread_rwlock_wrlock(&lock); + pthread_mutex_lock(&init_fini_lock); + } else { + pthread_mutex_unlock(&init_fini_lock); + pthread_rwlock_unlock(&lock); + } +} + +static struct dso **queue_ctors(struct dso *dso) +{ + size_t cnt, qpos, spos, i; + struct dso *p, **queue, **stack; + + if (ldd_mode) return 0; + + /* Bound on queue size is the total number of indirect deps. + * If a bfs deps list was built, we can use it. Otherwise, + * bound by the total number of DSOs, which is always safe and + * is reasonable we use it (for main app at startup). */ + if (dso->bfs_built) { + for (cnt=0; dso->deps[cnt]; cnt++) + dso->deps[cnt]->mark = 0; + cnt++; /* self, not included in deps */ + } else { + for (cnt=0, p=head; p; cnt++, p=p->next) + p->mark = 0; + } + cnt++; /* termination slot */ + if (dso==head && cnt <= countof(builtin_ctor_queue)) + queue = builtin_ctor_queue; + else + queue = calloc(cnt, sizeof *queue); + + if (!queue) { + error("Error allocating constructor queue: %m\n"); + if (runtime) longjmp(*rtld_fail, 1); + return 0; + } + + /* Opposite ends of the allocated buffer serve as an output queue + * and a working stack. Setup initial stack with just the argument + * dso and initial queue empty... */ + stack = queue; + qpos = 0; + spos = cnt; + stack[--spos] = dso; + dso->next_dep = 0; + dso->mark = 1; + + /* Then perform pseudo-DFS sort, but ignoring circular deps. */ + while (spos<cnt) { + p = stack[spos++]; + while (p->next_dep < p->ndeps_direct) { + if (p->deps[p->next_dep]->mark) { + p->next_dep++; + } else { + stack[--spos] = p; + p = p->deps[p->next_dep]; + p->next_dep = 0; + p->mark = 1; + } + } + queue[qpos++] = p; + } + queue[qpos] = 0; + for (i=0; i<qpos; i++) queue[i]->mark = 0; + for (i=0; i<qpos; i++) + if (queue[i]->ctor_visitor && queue[i]->ctor_visitor->tid < 0) { + error("State of %s is inconsistent due to multithreaded fork\n", + queue[i]->name); + free(queue); + if (runtime) longjmp(*rtld_fail, 1); + } + + return queue; +} + +static void do_init_fini(struct dso **queue) +{ + struct dso *p; + size_t dyn[DYN_CNT], i; + pthread_t self = __pthread_self(); + + pthread_mutex_lock(&init_fini_lock); + for (i=0; (p=queue[i]); i++) { + while ((p->ctor_visitor && p->ctor_visitor!=self) || shutting_down) + pthread_cond_wait(&ctor_cond, &init_fini_lock); + if (p->ctor_visitor || p->constructed) + continue; + p->ctor_visitor = self; + decode_vec(p->dynv, dyn, DYN_CNT); if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) { p->fini_next = fini_head; fini_head = p; } + + pthread_mutex_unlock(&init_fini_lock); + #ifndef NO_LEGACY_INITFINI if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT]) fpaddr(p, dyn[DT_INIT])(); @@ -1315,17 +1607,21 @@ static void do_init_fini(struct dso *p) size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]); while (n--) ((void (*)(void))*fn++)(); } - if (!need_locking && libc.threads_minus_1) { - need_locking = 1; - pthread_mutex_lock(&init_fini_lock); - } + + pthread_mutex_lock(&init_fini_lock); + p->ctor_visitor = 0; + p->constructed = 1; + pthread_cond_broadcast(&ctor_cond); } - if (need_locking) pthread_mutex_unlock(&init_fini_lock); + pthread_mutex_unlock(&init_fini_lock); } void __libc_start_init(void) { - do_init_fini(tail); + do_init_fini(main_ctor_queue); + if (!__malloc_replaced && main_ctor_queue != builtin_ctor_queue) + free(main_ctor_queue); + main_ctor_queue = 0; } static void dl_debug_state(void) @@ -1338,48 +1634,6 @@ void __init_tls(size_t *auxv) { } -hidden void *__tls_get_new(tls_mod_off_t *v) -{ - pthread_t self = __pthread_self(); - - /* Block signals to make accessing new TLS async-signal-safe */ - sigset_t set; - __block_all_sigs(&set); - if (v[0] <= self->dtv[0]) { - __restore_sigs(&set); - return (void *)(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 */ - uintptr_t *newdtv = p->new_dtv + - (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1); - memcpy(newdtv, self->dtv, (self->dtv[0]+1) * sizeof(uintptr_t)); - newdtv[0] = v[0]; - self->dtv = self->dtv_copy = newdtv; - - /* Get new TLS memory from all new DSOs up to the requested one */ - unsigned char *mem; - for (p=head; ; p=p->next) { - if (!p->tls_id || self->dtv[p->tls_id]) continue; - 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[p->tls_id] = (uintptr_t)mem + DTP_OFFSET; - memcpy(mem, p->tls.image, p->tls.len); - if (p->tls_id == v[0]) break; - } - __restore_sigs(&set); - return mem + v[1] + DTP_OFFSET; -} - static void update_tls_size() { libc.tls_cnt = tls_cnt; @@ -1392,6 +1646,56 @@ static void update_tls_size() tls_align); } +static void install_new_tls(void) +{ + sigset_t set; + pthread_t self = __pthread_self(), td; + struct dso *dtv_provider = container_of(tls_tail, struct dso, tls); + uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv; + struct dso *p; + size_t i, j; + size_t old_cnt = self->dtv[0]; + + __block_app_sigs(&set); + __tl_lock(); + /* Copy existing dtv contents from all existing threads. */ + for (i=0, td=self; !i || td!=self; i++, td=td->next) { + memcpy(newdtv+i, td->dtv, + (old_cnt+1)*sizeof(uintptr_t)); + newdtv[i][0] = tls_cnt; + } + /* Install new dtls into the enlarged, uninstalled dtv copies. */ + for (p=head; ; p=p->next) { + if (p->tls_id <= old_cnt) continue; + unsigned char *mem = p->new_tls; + for (j=0; j<i; j++) { + unsigned char *new = mem; + new += ((uintptr_t)p->tls.image - (uintptr_t)mem) + & (p->tls.align-1); + memcpy(new, p->tls.image, p->tls.len); + newdtv[j][p->tls_id] = + (uintptr_t)new + DTP_OFFSET; + mem += p->tls.size + p->tls.align; + } + if (p->tls_id == tls_cnt) break; + } + + /* Broadcast barrier to ensure contents of new dtv is visible + * if the new dtv pointer is. The __membarrier function has a + * fallback emulation using signals for kernels that lack the + * feature at the syscall level. */ + + __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0); + + /* Install new dtv for each thread. */ + for (j=0, td=self; !j || td!=self; j++, td=td->next) { + td->dtv = newdtv[j]; + } + + __tl_unlock(); + __restore_sigs(&set); +} + /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the * following stage 2 and stage 3 functions via primitive symbolic lookup * since it does not have access to their addresses to begin with. */ @@ -1405,13 +1709,14 @@ static void update_tls_size() hidden void __dls2(unsigned char *base, size_t *sp) { + size_t *auxv; + for (auxv=sp+1+*sp+1; *auxv; auxv++); + auxv++; if (DL_FDPIC) { void *p1 = (void *)sp[-2]; void *p2 = (void *)sp[-1]; if (!p1) { - size_t *auxv, aux[AUX_CNT]; - for (auxv=sp+1+*sp+1; *auxv; auxv++); - auxv++; + size_t aux[AUX_CNT]; decode_vec(auxv, aux, AUX_CNT); if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE]; else ldso.base = (void *)(aux[AT_PHDR] & -4096); @@ -1422,11 +1727,12 @@ hidden void __dls2(unsigned char *base, size_t *sp) } else { ldso.base = base; } - Ehdr *ehdr = (void *)ldso.base; + Ehdr *ehdr = __ehdr_start ? (void *)__ehdr_start : (void *)ldso.base; ldso.name = ldso.shortname = "libc.so"; ldso.phnum = ehdr->e_phnum; ldso.phdr = laddr(&ldso, ehdr->e_phoff); ldso.phentsize = ehdr->e_phentsize; + search_vec(auxv, &ldso_page_size, AT_PAGESZ); kernel_mapped_dso(&ldso); decode_dyn(&ldso); @@ -1457,8 +1763,8 @@ hidden void __dls2(unsigned char *base, size_t *sp) * symbolically as a barrier against moving the address * load across the above relocation processing. */ struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0); - if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp); - else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp); + if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp, auxv); + else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp, auxv); } /* Stage 2b sets up a valid thread pointer, which requires relocations @@ -1467,11 +1773,13 @@ hidden void __dls2(unsigned char *base, size_t *sp) * so that loads of the thread pointer and &errno can be pure/const and * thereby hoistable. */ -_Noreturn void __dls2b(size_t *sp) +void __dls2b(size_t *sp, size_t *auxv) { /* Setup early thread pointer in builtin_tls for ldso/libc itself to * use during dynamic linking. If possible it will also serve as the * thread pointer at runtime. */ + search_vec(auxv, &__hwcap, AT_HWCAP); + libc.auxv = auxv; libc.tls_size = sizeof builtin_tls; libc.tls_align = tls_align; if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) { @@ -1479,8 +1787,8 @@ _Noreturn void __dls2b(size_t *sp) } struct symdef dls3_def = find_sym(&ldso, "__dls3", 0); - if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp); - else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp); + if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp, auxv); + else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp, auxv); } /* Stage 3 of the dynamic linker is called with the dynamic linker/libc @@ -1488,10 +1796,10 @@ _Noreturn void __dls2b(size_t *sp) * process dependencies and relocations for the main application and * transfer control to its entry point. */ -_Noreturn void __dls3(size_t *sp) +void __dls3(size_t *sp, size_t *auxv) { static struct dso app, vdso; - size_t aux[AUX_CNT], *auxv; + size_t aux[AUX_CNT]; size_t i; char *env_preload=0; char *replace_argv0=0; @@ -1504,10 +1812,9 @@ _Noreturn void __dls3(size_t *sp) /* Find aux vector just past environ[] and use it to initialize * global data that may be needed before we can make syscalls. */ __environ = envp; - for (i=argc+1; argv[i]; i++); - libc.auxv = auxv = (void *)(argv+i+1); decode_vec(auxv, aux, AUX_CNT); - __hwcap = aux[AT_HWCAP]; + search_vec(auxv, &__sysinfo, AT_SYSINFO); + __pthread_self()->sysinfo = __sysinfo; libc.page_size = aux[AT_PAGESZ]; libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID] || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]); @@ -1518,6 +1825,9 @@ _Noreturn void __dls3(size_t *sp) env_preload = getenv("LD_PRELOAD"); } + /* Activate error handler function */ + error = error_impl; + /* If the main program was already loaded by the kernel, * AT_PHDR will point to some location other than the dynamic * linker's program headers. */ @@ -1593,7 +1903,7 @@ _Noreturn void __dls3(size_t *sp) dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno)); _exit(1); } - Ehdr *ehdr = (void *)map_library(fd, &app); + Ehdr *ehdr = map_library(fd, &app); if (!ehdr) { dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]); _exit(1); @@ -1617,10 +1927,9 @@ _Noreturn void __dls3(size_t *sp) app.tls_id = tls_cnt = 1; #ifdef TLS_ABOVE_TP app.tls.offset = GAP_ABOVE_TP; - app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1); - tls_offset = app.tls.offset + app.tls.size - + ( -((uintptr_t)app.tls.image + app.tls.size) - & (app.tls.align-1) ); + app.tls.offset += (-GAP_ABOVE_TP + (uintptr_t)app.tls.image) + & (app.tls.align-1); + tls_offset = app.tls.offset + app.tls.size; #else tls_offset = app.tls.offset = app.tls.size + ( -((uintptr_t)app.tls.image + app.tls.size) @@ -1650,6 +1959,7 @@ _Noreturn void __dls3(size_t *sp) reclaim_gaps(&ldso); /* Load preload/needed libraries, add symbols to global namespace. */ + ldso.deps = (struct dso **)no_deps; if (env_preload) load_preload(env_preload); load_deps(&app); for (struct dso *p=head; p; p=p->next) @@ -1671,6 +1981,7 @@ _Noreturn void __dls3(size_t *sp) vdso.name = ""; vdso.shortname = "linux-gate.so.1"; vdso.relocated = 1; + vdso.deps = (struct dso **)no_deps; decode_dyn(&vdso); vdso.prev = tail; tail->next = &vdso; @@ -1684,21 +1995,42 @@ _Noreturn void __dls3(size_t *sp) size_t *ptr = (size_t *) app.dynv[i+1]; *ptr = (size_t)&debug; } + if (app.dynv[i]==DT_DEBUG_INDIRECT_REL) { + size_t *ptr = (size_t *)((size_t)&app.dynv[i] + app.dynv[i+1]); + *ptr = (size_t)&debug; + } } - /* The main program must be relocated LAST since it may contin - * copy relocations which depend on libraries' relocations. */ - reloc_all(app.next); - reloc_all(&app); + /* This must be done before final relocations, since it calls + * malloc, which may be provided by the application. Calling any + * application code prior to the jump to its entry point is not + * valid in our model and does not work with FDPIC, where there + * are additional relocation-like fixups that only the entry point + * code can see to perform. */ + main_ctor_queue = queue_ctors(&app); + /* Initial TLS must also be allocated before final relocations + * might result in calloc being a call to application code. */ update_tls_size(); + void *initial_tls = builtin_tls; if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) { - void *initial_tls = calloc(libc.tls_size, 1); + initial_tls = calloc(libc.tls_size, 1); if (!initial_tls) { dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n", argv[0], libc.tls_size); _exit(127); } + } + static_tls_cnt = tls_cnt; + + /* The main program must be relocated LAST since it may contain + * copy relocations which depend on libraries' relocations. */ + reloc_all(app.next); + reloc_all(&app); + + /* Actual copying to new TLS needs to happen after relocations, + * since the TLS images might have contained relocated addresses. */ + if (initial_tls != builtin_tls) { if (__init_tp(__copy_tls(initial_tls)) < 0) { a_crash(); } @@ -1712,7 +2044,6 @@ _Noreturn void __dls3(size_t *sp) if (__copy_tls((void*)builtin_tls) != self) a_crash(); libc.tls_size = tmp_tls_size; } - static_tls_cnt = tls_cnt; if (ldso_fail) _exit(127); if (ldd_mode) _exit(0); @@ -1722,6 +2053,8 @@ _Noreturn void __dls3(size_t *sp) * possibility of incomplete replacement. */ if (find_sym(head, "malloc", 1).dso != &ldso) __malloc_replaced = 1; + if (find_sym(head, "aligned_alloc", 1).dso != &ldso) + __aligned_alloc_replaced = 1; /* Switch to runtime mode: any further failures in the dynamic * linker are a reportable failure rather than a fatal startup @@ -1732,7 +2065,7 @@ _Noreturn void __dls3(size_t *sp) debug.bp = dl_debug_state; debug.head = head; debug.base = ldso.base; - debug.state = 0; + debug.state = RT_CONSISTENT; _dl_debug_state(); if (replace_argv0) argv[0] = replace_argv0; @@ -1773,6 +2106,7 @@ void *dlopen(const char *file, int mode) size_t i; int cs; jmp_buf jb; + struct dso **volatile ctor_queue = 0; if (!file) return head; @@ -1780,7 +2114,14 @@ void *dlopen(const char *file, int mode) pthread_rwlock_wrlock(&lock); __inhibit_ptc(); + debug.state = RT_ADD; + _dl_debug_state(); + p = 0; + if (shutting_down) { + error("Cannot dlopen while program is exiting."); + goto end; + } orig_tls_tail = tls_tail; orig_tls_cnt = tls_cnt; orig_tls_offset = tls_offset; @@ -1804,11 +2145,12 @@ void *dlopen(const char *file, int mode) free(p->funcdescs); if (p->rpath != p->rpath_orig) free(p->rpath); - if (p->deps != &nodeps_dummy) - free(p->deps); + free(p->deps); unmap_library(p); free(p); } + free(ctor_queue); + ctor_queue = 0; if (!orig_tls_tail) libc.tls_head = 0; tls_tail = orig_tls_tail; if (tls_tail) tls_tail->next = 0; @@ -1831,24 +2173,26 @@ void *dlopen(const char *file, int mode) } /* First load handling */ - int first_load = !p->deps; - if (first_load) { - load_deps(p); - if (!p->relocated && (mode & RTLD_LAZY)) { - prepare_lazy(p); - for (i=0; p->deps[i]; i++) - if (!p->deps[i]->relocated) - prepare_lazy(p->deps[i]); - } + load_deps(p); + extend_bfs_deps(p); + pthread_mutex_lock(&init_fini_lock); + int constructed = p->constructed; + pthread_mutex_unlock(&init_fini_lock); + if (!constructed) ctor_queue = queue_ctors(p); + if (!p->relocated && (mode & RTLD_LAZY)) { + prepare_lazy(p); + for (i=0; p->deps[i]; i++) + if (!p->deps[i]->relocated) + prepare_lazy(p->deps[i]); } - if (first_load || (mode & RTLD_GLOBAL)) { + if (!p->relocated || (mode & RTLD_GLOBAL)) { /* Make new symbols global, at least temporarily, so we can do * relocations. If not RTLD_GLOBAL, this is reverted below. */ add_syms(p); for (i=0; p->deps[i]; i++) add_syms(p->deps[i]); } - if (first_load) { + if (!p->relocated) { reloc_all(p); } @@ -1864,13 +2208,19 @@ void *dlopen(const char *file, int mode) redo_lazy_relocs(); update_tls_size(); - _dl_debug_state(); + if (tls_cnt != orig_tls_cnt) + install_new_tls(); orig_tail = tail; end: + debug.state = RT_CONSISTENT; + _dl_debug_state(); __release_ptc(); if (p) gencnt++; pthread_rwlock_unlock(&lock); - if (p) do_init_fini(orig_tail); + if (ctor_queue) { + do_init_fini(ctor_queue); + free(ctor_queue); + } pthread_setcancelstate(cs, 0); return p; } @@ -1918,58 +2268,27 @@ 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; - 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; + } 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 ((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) @@ -2017,7 +2336,7 @@ int dladdr(const void *addr_arg, Dl_info *info) } } - if (bestsym && besterr > bestsym->st_size-1) { + if (best && besterr > bestsym->st_size-1) { best = 0; bestsym = 0; } @@ -2048,6 +2367,33 @@ hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra return res; } +hidden void *__dlsym_redir_time64(void *restrict p, const char *restrict s, void *restrict ra) +{ +#if _REDIR_TIME64 + const char *suffix, *suffix2 = ""; + char redir[36]; + + /* Map the symbol name to a time64 version of itself according to the + * pattern used for naming the redirected time64 symbols. */ + size_t l = strnlen(s, sizeof redir); + if (l<4 || l==sizeof redir) goto no_redir; + if (s[l-2]=='_' && s[l-1]=='r') { + l -= 2; + suffix2 = s+l; + } + if (l<4) goto no_redir; + if (!strcmp(s+l-4, "time")) suffix = "64"; + else suffix = "_time64"; + + /* Use the presence of the remapped symbol name in libc to determine + * whether it's one that requires time64 redirection; replace if so. */ + snprintf(redir, sizeof redir, "__%.*s%s%s", (int)l, s, suffix, suffix2); + if (find_sym(&ldso, redir, 1).sym) s = redir; +no_redir: +#endif + return __dlsym(p, s, ra); +} + int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data) { struct dso *current; @@ -2061,7 +2407,8 @@ int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void info.dlpi_adds = gencnt; info.dlpi_subs = 0; info.dlpi_tls_modid = current->tls_id; - info.dlpi_tls_data = current->tls.image; + info.dlpi_tls_data = !current->tls_id ? 0 : + __tls_get_addr((tls_mod_off_t[]){current->tls_id,0}); ret = (callback)(&info, sizeof (info), data); @@ -2074,7 +2421,7 @@ int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void return ret; } -static void error(const char *fmt, ...) +static void error_impl(const char *fmt, ...) { va_list ap; va_start(ap, fmt); @@ -2088,3 +2435,7 @@ static void error(const char *fmt, ...) __dl_vseterr(fmt, ap); va_end(ap); } + +static void error_noop(const char *fmt, ...) +{ +} |