| #define _GNU_SOURCE |
| #define SYSCALL_NO_TLS 1 |
| #include <stdlib.h> |
| #include <stdarg.h> |
| #include <stddef.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <stdint.h> |
| #include <elf.h> |
| #include <sys/mman.h> |
| #include <limits.h> |
| #include <fcntl.h> |
| #include <sys/stat.h> |
| #include <errno.h> |
| #include <link.h> |
| #include <setjmp.h> |
| #include <pthread.h> |
| #include <ctype.h> |
| #include <dlfcn.h> |
| #include <semaphore.h> |
| #include <sys/membarrier.h> |
| #include "pthread_impl.h" |
| #include "fork_impl.h" |
| #include "dynlink.h" |
| |
| 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; |
| void (*bp)(void); |
| int state; |
| void *base; |
| }; |
| |
| struct td_index { |
| size_t args[2]; |
| struct td_index *next; |
| }; |
| |
| struct dso { |
| #if DL_FDPIC |
| struct fdpic_loadmap *loadmap; |
| #else |
| unsigned char *base; |
| #endif |
| char *name; |
| size_t *dynv; |
| struct dso *next, *prev; |
| |
| Phdr *phdr; |
| int phnum; |
| size_t phentsize; |
| Sym *syms; |
| Elf_Symndx *hashtab; |
| uint32_t *ghashtab; |
| int16_t *versym; |
| char *strings; |
| struct dso *syms_next, *lazy_next; |
| size_t *lazy, lazy_cnt; |
| unsigned char *map; |
| size_t map_len; |
| dev_t dev; |
| ino_t ino; |
| 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; |
| struct td_index *td_index; |
| struct dso *fini_next; |
| char *shortname; |
| #if DL_FDPIC |
| unsigned char *base; |
| #else |
| struct fdpic_loadmap *loadmap; |
| #endif |
| struct funcdesc { |
| void *addr; |
| size_t *got; |
| } *funcdescs; |
| size_t *got; |
| char buf[]; |
| }; |
| |
| struct symdef { |
| Sym *sym; |
| struct dso *dso; |
| }; |
| |
| typedef void (*stage3_func)(size_t *, size_t *); |
| |
| static struct builtin_tls { |
| char c; |
| struct pthread pt; |
| void *space[16]; |
| } builtin_tls[1]; |
| #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt) |
| |
| #define ADDEND_LIMIT 4096 |
| static size_t *saved_addends, *apply_addends_to; |
| |
| static struct dso ldso; |
| static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head; |
| static char *env_path, *sys_path; |
| static unsigned long long gencnt; |
| 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; |
| 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; |
| |
| 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; |
| |
| extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void); |
| |
| weak_alias(__init_array_start, __init_array_end); |
| weak_alias(__fini_array_start, __fini_array_end); |
| |
| static int dl_strcmp(const char *l, const char *r) |
| { |
| for (; *l==*r && *l; l++, r++); |
| return *(unsigned char *)l - *(unsigned char *)r; |
| } |
| #define strcmp(l,r) dl_strcmp(l,r) |
| |
| /* Compute load address for a virtual address in a given dso. */ |
| #if DL_FDPIC |
| static void *laddr(const struct dso *p, size_t v) |
| { |
| size_t j=0; |
| if (!p->loadmap) return p->base + v; |
| for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++); |
| return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr); |
| } |
| static void *laddr_pg(const struct dso *p, size_t v) |
| { |
| size_t j=0; |
| size_t pgsz = PAGE_SIZE; |
| if (!p->loadmap) return p->base + v; |
| for (j=0; ; j++) { |
| size_t a = p->loadmap->segs[j].p_vaddr; |
| size_t b = a + p->loadmap->segs[j].p_memsz; |
| a &= -pgsz; |
| b += pgsz-1; |
| b &= -pgsz; |
| if (v-a<b-a) break; |
| } |
| return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr); |
| } |
| 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) |
| #define fpaddr(p, v) ((void (*)())laddr(p, v)) |
| #endif |
| |
| 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) { |
| if (v[0] < 8*sizeof(long)) |
| a[0] |= 1UL<<v[0]; |
| a[v[0]] = v[1]; |
| } |
| } |
| |
| static int search_vec(size_t *v, size_t *r, size_t key) |
| { |
| for (; v[0]!=key; v+=2) |
| if (!v[0]) return 0; |
| *r = v[1]; |
| return 1; |
| } |
| |
| static uint32_t sysv_hash(const char *s0) |
| { |
| const unsigned char *s = (void *)s0; |
| uint_fast32_t h = 0; |
| while (*s) { |
| h = 16*h + *s++; |
| h ^= h>>24 & 0xf0; |
| } |
| return h & 0xfffffff; |
| } |
| |
| static uint32_t gnu_hash(const char *s0) |
| { |
| const unsigned char *s = (void *)s0; |
| uint_fast32_t h = 5381; |
| for (; *s; s++) |
| h += h*32 + *s; |
| return h; |
| } |
| |
| static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso) |
| { |
| size_t i; |
| Sym *syms = dso->syms; |
| Elf_Symndx *hashtab = dso->hashtab; |
| char *strings = dso->strings; |
| for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) { |
| if ((!dso->versym || dso->versym[i] >= 0) |
| && (!strcmp(s, strings+syms[i].st_name))) |
| return syms+i; |
| } |
| return 0; |
| } |
| |
| static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s) |
| { |
| uint32_t nbuckets = hashtab[0]; |
| uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4); |
| uint32_t i = buckets[h1 % nbuckets]; |
| |
| if (!i) return 0; |
| |
| uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]); |
| |
| for (h1 |= 1; ; i++) { |
| uint32_t h2 = *hashval++; |
| if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0) |
| && !strcmp(s, dso->strings + dso->syms[i].st_name)) |
| return dso->syms+i; |
| if (h2 & 1) break; |
| } |
| |
| return 0; |
| } |
| |
| static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask) |
| { |
| const size_t *bloomwords = (const void *)(hashtab+4); |
| size_t f = bloomwords[fofs & (hashtab[2]-1)]; |
| if (!(f & fmask)) return 0; |
| |
| f >>= (h1 >> hashtab[3]) % (8 * sizeof f); |
| if (!(f & 1)) return 0; |
| |
| return gnu_lookup(h1, hashtab, dso, s); |
| } |
| |
| #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS) |
| #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE) |
| |
| #ifndef ARCH_SYM_REJECT_UND |
| #define ARCH_SYM_REJECT_UND(s) 0 |
| #endif |
| |
| #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}; |
| 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); |
| } else { |
| if (!h) h = sysv_hash(s); |
| sym = sysv_lookup(s, h, dso); |
| } |
| if (!sym) continue; |
| if (!sym->st_shndx) |
| if (need_def || (sym->st_info&0xf) == STT_TLS |
| || ARCH_SYM_REJECT_UND(sym)) |
| continue; |
| if (!sym->st_value) |
| if ((sym->st_info&0xf) != STT_TLS) |
| continue; |
| if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue; |
| if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue; |
| def.sym = sym; |
| def.dso = dso; |
| break; |
| } |
| 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; |
| Sym *syms = dso->syms; |
| char *strings = dso->strings; |
| Sym *sym; |
| const char *name; |
| void *ctx; |
| int type; |
| int sym_index; |
| struct symdef def; |
| size_t *reloc_addr; |
| size_t sym_val; |
| size_t tls_val; |
| size_t addend; |
| int skip_relative = 0, reuse_addends = 0, save_slot = 0; |
| |
| if (dso == &ldso) { |
| /* Only ldso's REL table needs addend saving/reuse. */ |
| if (rel == apply_addends_to) |
| reuse_addends = 1; |
| skip_relative = 1; |
| } |
| |
| for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) { |
| if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue; |
| type = R_TYPE(rel[1]); |
| if (type == REL_NONE) continue; |
| reloc_addr = laddr(dso, rel[0]); |
| |
| if (stride > 2) { |
| addend = rel[2]; |
| } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) { |
| addend = 0; |
| } else if (reuse_addends) { |
| /* Save original addend in stage 2 where the dso |
| * chain consists of just ldso; otherwise read back |
| * saved addend since the inline one was clobbered. */ |
| if (head==&ldso) |
| saved_addends[save_slot] = *reloc_addr; |
| addend = saved_addends[save_slot++]; |
| } else { |
| addend = *reloc_addr; |
| } |
| |
| sym_index = R_SYM(rel[1]); |
| if (sym_index) { |
| sym = syms + sym_index; |
| name = strings + sym->st_name; |
| ctx = type==REL_COPY ? head->syms_next : head; |
| 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)) { |
| dso->lazy[3*dso->lazy_cnt+0] = rel[0]; |
| dso->lazy[3*dso->lazy_cnt+1] = rel[1]; |
| dso->lazy[3*dso->lazy_cnt+2] = addend; |
| dso->lazy_cnt++; |
| continue; |
| } |
| error("Error relocating %s: %s: symbol not found", |
| dso->name, name); |
| if (runtime) longjmp(*rtld_fail, 1); |
| continue; |
| } |
| } else { |
| sym = 0; |
| def.sym = 0; |
| def.dso = dso; |
| } |
| |
| sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0; |
| tls_val = def.sym ? def.sym->st_value : 0; |
| |
| if ((type == REL_TPOFF || type == REL_TPOFF_NEG) |
| && 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); |
| longjmp(*rtld_fail, 1); |
| } |
| |
| switch(type) { |
| case REL_OFFSET: |
| addend -= (size_t)reloc_addr; |
| case REL_SYMBOLIC: |
| case REL_GOT: |
| 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; |
| case REL_SYM_OR_REL: |
| if (sym) *reloc_addr = sym_val + addend; |
| else *reloc_addr = (size_t)base + addend; |
| break; |
| case REL_COPY: |
| memcpy(reloc_addr, (void *)sym_val, sym->st_size); |
| break; |
| case REL_OFFSET32: |
| *(uint32_t *)reloc_addr = sym_val + addend |
| - (size_t)reloc_addr; |
| break; |
| case REL_FUNCDESC: |
| *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs |
| + (def.sym - def.dso->syms)) : 0; |
| break; |
| case REL_FUNCDESC_VAL: |
| if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val; |
| else *reloc_addr = sym_val; |
| reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0; |
| break; |
| case REL_DTPMOD: |
| *reloc_addr = def.dso->tls_id; |
| break; |
| case REL_DTPOFF: |
| *reloc_addr = tls_val + addend - DTP_OFFSET; |
| break; |
| #ifdef TLS_ABOVE_TP |
| case REL_TPOFF: |
| *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend; |
| break; |
| #else |
| case REL_TPOFF: |
| *reloc_addr = tls_val - def.dso->tls.offset + addend; |
| break; |
| case REL_TPOFF_NEG: |
| *reloc_addr = def.dso->tls.offset - tls_val + addend; |
| break; |
| #endif |
| case REL_TLSDESC: |
| 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( |
| "Error relocating %s: cannot allocate TLSDESC for %s", |
| dso->name, sym ? name : "(local)" ); |
| longjmp(*rtld_fail, 1); |
| } |
| new->next = dso->td_index; |
| dso->td_index = new; |
| new->args[0] = def.dso->tls_id; |
| new->args[1] = tls_val + addend - DTP_OFFSET; |
| reloc_addr[0] = (size_t)__tlsdesc_dynamic; |
| reloc_addr[1] = (size_t)new; |
| } else { |
| reloc_addr[0] = (size_t)__tlsdesc_static; |
| #ifdef TLS_ABOVE_TP |
| reloc_addr[1] = tls_val + def.dso->tls.offset |
| + TPOFF_K + addend; |
| #else |
| reloc_addr[1] = tls_val - def.dso->tls.offset |
| + addend; |
| #endif |
| } |
| /* Some archs (32-bit ARM at least) invert the order of |
| * the descriptor members. Fix them up here. */ |
| 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", |
| dso->name, type); |
| if (runtime) longjmp(*rtld_fail, 1); |
| continue; |
| } |
| } |
| } |
| |
| 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; |
| lazy_head = 0; |
| for (; p; p=next) { |
| next = p->lazy_next; |
| size_t size = p->lazy_cnt*3*sizeof(size_t); |
| p->lazy_cnt = 0; |
| do_relocs(p, p->lazy, size, 3); |
| if (p->lazy_cnt) { |
| p->lazy_next = lazy_head; |
| lazy_head = p; |
| } else { |
| free(p->lazy); |
| p->lazy = 0; |
| p->lazy_next = 0; |
| } |
| } |
| } |
| |
| /* A huge hack: to make up for the wastefulness of shared libraries |
| * needing at least a page of dirty memory even if they have no global |
| * data, we reclaim the gaps at the beginning and end of writable maps |
| * and "donate" them to the heap. */ |
| |
| static void reclaim(struct dso *dso, size_t start, size_t end) |
| { |
| if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end; |
| if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start; |
| if (start >= end) return; |
| char *base = laddr_pg(dso, start); |
| __malloc_donate(base, base+(end-start)); |
| } |
| |
| static void reclaim_gaps(struct dso *dso) |
| { |
| Phdr *ph = dso->phdr; |
| size_t phcnt = dso->phnum; |
| |
| for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) { |
| if (ph->p_type!=PT_LOAD) continue; |
| if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue; |
| reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr); |
| reclaim(dso, ph->p_vaddr+ph->p_memsz, |
| ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE); |
| } |
| } |
| |
| 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) |
| return q; |
| no_map_fixed = 1; |
| } |
| /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */ |
| if (flags & MAP_ANONYMOUS) { |
| memset(p, 0, n); |
| return p; |
| } |
| ssize_t r; |
| if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED; |
| for (q=p; n; q+=r, off+=r, n-=r) { |
| r = read(fd, q, n); |
| if (r < 0 && errno != EINTR) return MAP_FAILED; |
| if (!r) { |
| memset(q, 0, n); |
| break; |
| } |
| } |
| return p; |
| } |
| |
| static void unmap_library(struct dso *dso) |
| { |
| if (dso->loadmap) { |
| size_t i; |
| for (i=0; i<dso->loadmap->nsegs; i++) { |
| if (!dso->loadmap->segs[i].p_memsz) |
| continue; |
| munmap((void *)dso->loadmap->segs[i].addr, |
| dso->loadmap->segs[i].p_memsz); |
| } |
| free(dso->loadmap); |
| } else if (dso->map && dso->map_len) { |
| munmap(dso->map, dso->map_len); |
| } |
| } |
| |
| static void *map_library(int fd, struct dso *dso) |
| { |
| Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)]; |
| void *allocated_buf=0; |
| size_t phsize; |
| size_t addr_min=SIZE_MAX, addr_max=0, map_len; |
| size_t this_min, this_max; |
| size_t nsegs = 0; |
| off_t off_start; |
| Ehdr *eh; |
| Phdr *ph, *ph0; |
| unsigned prot; |
| unsigned char *map=MAP_FAILED, *base; |
| size_t dyn=0; |
| size_t tls_image=0; |
| size_t i; |
| |
| ssize_t l = read(fd, buf, sizeof buf); |
| eh = buf; |
| if (l<0) return 0; |
| if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC)) |
| goto noexec; |
| phsize = eh->e_phentsize * eh->e_phnum; |
| if (phsize > sizeof buf - sizeof *eh) { |
| allocated_buf = malloc(phsize); |
| if (!allocated_buf) return 0; |
| l = pread(fd, allocated_buf, phsize, eh->e_phoff); |
| if (l < 0) goto error; |
| if (l != phsize) goto noexec; |
| ph = ph0 = allocated_buf; |
| } else if (eh->e_phoff + phsize > l) { |
| l = pread(fd, buf+1, phsize, eh->e_phoff); |
| if (l < 0) goto error; |
| if (l != phsize) goto noexec; |
| ph = ph0 = (void *)(buf + 1); |
| } else { |
| ph = ph0 = (void *)((char *)buf + eh->e_phoff); |
| } |
| for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) { |
| if (ph->p_type == PT_DYNAMIC) { |
| dyn = ph->p_vaddr; |
| } else if (ph->p_type == PT_TLS) { |
| tls_image = ph->p_vaddr; |
| dso->tls.align = ph->p_align; |
| dso->tls.len = ph->p_filesz; |
| dso->tls.size = ph->p_memsz; |
| } else if (ph->p_type == PT_GNU_RELRO) { |
| dso->relro_start = ph->p_vaddr & -PAGE_SIZE; |
| dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE; |
| } else if (ph->p_type == PT_GNU_STACK) { |
| if (!runtime && ph->p_memsz > __default_stacksize) { |
| __default_stacksize = |
| ph->p_memsz < DEFAULT_STACK_MAX ? |
| ph->p_memsz : DEFAULT_STACK_MAX; |
| } |
| } |
| if (ph->p_type != PT_LOAD) continue; |
| nsegs++; |
| if (ph->p_vaddr < addr_min) { |
| addr_min = ph->p_vaddr; |
| off_start = ph->p_offset; |
| prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) | |
| ((ph->p_flags&PF_W) ? PROT_WRITE: 0) | |
| ((ph->p_flags&PF_X) ? PROT_EXEC : 0)); |
| } |
| if (ph->p_vaddr+ph->p_memsz > addr_max) { |
| addr_max = ph->p_vaddr+ph->p_memsz; |
| } |
| } |
| if (!dyn) goto noexec; |
| if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) { |
| dso->loadmap = calloc(1, sizeof *dso->loadmap |
| + nsegs * sizeof *dso->loadmap->segs); |
| if (!dso->loadmap) goto error; |
| dso->loadmap->nsegs = nsegs; |
| for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) { |
| if (ph->p_type != PT_LOAD) continue; |
| prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) | |
| ((ph->p_flags&PF_W) ? PROT_WRITE: 0) | |
| ((ph->p_flags&PF_X) ? PROT_EXEC : 0)); |
| map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1), |
| prot, MAP_PRIVATE, |
| fd, ph->p_offset & -PAGE_SIZE); |
| if (map == MAP_FAILED) { |
| unmap_library(dso); |
| goto error; |
| } |
| dso->loadmap->segs[i].addr = (size_t)map + |
| (ph->p_vaddr & PAGE_SIZE-1); |
| dso->loadmap->segs[i].p_vaddr = ph->p_vaddr; |
| dso->loadmap->segs[i].p_memsz = ph->p_memsz; |
| i++; |
| if (prot & PROT_WRITE) { |
| size_t brk = (ph->p_vaddr & PAGE_SIZE-1) |
| + ph->p_filesz; |
| size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE; |
| size_t pgend = brk + ph->p_memsz - ph->p_filesz |
| + PAGE_SIZE-1 & -PAGE_SIZE; |
| if (pgend > pgbrk && mmap_fixed(map+pgbrk, |
| pgend-pgbrk, prot, |
| MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, |
| -1, off_start) == MAP_FAILED) |
| goto error; |
| memset(map + brk, 0, pgbrk-brk); |
| } |
| } |
| map = (void *)dso->loadmap->segs[0].addr; |
| map_len = 0; |
| goto done_mapping; |
| } |
| addr_max += PAGE_SIZE-1; |
| addr_max &= -PAGE_SIZE; |
| addr_min &= -PAGE_SIZE; |
| off_start &= -PAGE_SIZE; |
| map_len = addr_max - addr_min + off_start; |
| /* The first time, we map too much, possibly even more than |
| * the length of the file. This is okay because we will not |
| * use the invalid part; we just need to reserve the right |
| * amount of virtual address space to map over later. */ |
| map = DL_NOMMU_SUPPORT |
| ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC, |
| MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) |
| : mmap((void *)addr_min, map_len, prot, |
| MAP_PRIVATE, fd, off_start); |
| if (map==MAP_FAILED) goto error; |
| dso->map = map; |
| dso->map_len = map_len; |
| /* If the loaded file is not relocatable and the requested address is |
| * not available, then the load operation must fail. */ |
| if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) { |
| errno = EBUSY; |
| goto error; |
| } |
| base = map - addr_min; |
| dso->phdr = 0; |
| dso->phnum = 0; |
| for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) { |
| if (ph->p_type != PT_LOAD) continue; |
| /* Check if the programs headers are in this load segment, and |
| * if so, record the address for use by dl_iterate_phdr. */ |
| if (!dso->phdr && eh->e_phoff >= ph->p_offset |
| && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) { |
| dso->phdr = (void *)(base + ph->p_vaddr |
| + (eh->e_phoff-ph->p_offset)); |
| dso->phnum = eh->e_phnum; |
| dso->phentsize = eh->e_phentsize; |
| } |
| this_min = ph->p_vaddr & -PAGE_SIZE; |
| this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE; |
| off_start = ph->p_offset & -PAGE_SIZE; |
| prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) | |
| ((ph->p_flags&PF_W) ? PROT_WRITE: 0) | |
| ((ph->p_flags&PF_X) ? PROT_EXEC : 0)); |
| /* Reuse the existing mapping for the lowest-address LOAD */ |
| if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT) |
| if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED) |
| goto error; |
| if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) { |
| size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz; |
| size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE; |
| memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1); |
| if (pgbrk-(size_t)base < this_max && mmap_fixed((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED) |
| goto error; |
| } |
| } |
| for (i=0; ((size_t *)(base+dyn))[i]; i+=2) |
| if (((size_t *)(base+dyn))[i]==DT_TEXTREL) { |
| if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) |
| && errno != ENOSYS) |
| goto error; |
| break; |
| } |
| done_mapping: |
| dso->base = base; |
| dso->dynv = laddr(dso, dyn); |
| if (dso->tls.size) dso->tls.image = laddr(dso, tls_image); |
| free(allocated_buf); |
| return map; |
| noexec: |
| errno = ENOEXEC; |
| error: |
| if (map!=MAP_FAILED) unmap_library(dso); |
| free(allocated_buf); |
| return 0; |
| } |
| |
| static int path_open(const char *name, const char *s, char *buf, size_t buf_size) |
| { |
| size_t l; |
| int fd; |
| for (;;) { |
| s += strspn(s, ":\n"); |
| l = strcspn(s, ":\n"); |
| if (l-1 >= INT_MAX) return -1; |
| if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) { |
| if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd; |
| switch (errno) { |
| case ENOENT: |
| case ENOTDIR: |
| case EACCES: |
| case ENAMETOOLONG: |
| break; |
| default: |
| /* Any negative value but -1 will inhibit |
| * futher path search. */ |
| return -2; |
| } |
| } |
| s += l; |
| } |
| } |
| |
| static int fixup_rpath(struct dso *p, char *buf, size_t buf_size) |
| { |
| size_t n, l; |
| const char *s, *t, *origin; |
| char *d; |
| if (p->rpath || !p->rpath_orig) return 0; |
| if (!strchr(p->rpath_orig, '$')) { |
| p->rpath = p->rpath_orig; |
| return 0; |
| } |
| n = 0; |
| s = p->rpath_orig; |
| while ((t=strchr(s, '$'))) { |
| if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9)) |
| return 0; |
| s = t+1; |
| n++; |
| } |
| if (n > SSIZE_MAX/PATH_MAX) return 0; |
| |
| if (p->kernel_mapped) { |
| /* $ORIGIN searches cannot be performed for the main program |
| * when it is suid/sgid/AT_SECURE. This is because the |
| * pathname is under the control of the caller of execve. |
| * For libraries, however, $ORIGIN can be processed safely |
| * since the library's pathname came from a trusted source |
| * (either system paths or a call to dlopen). */ |
| if (libc.secure) |
| return 0; |
| l = readlink("/proc/self/exe", buf, buf_size); |
| if (l == -1) switch (errno) { |
| case ENOENT: |
| case ENOTDIR: |
| case EACCES: |
| return 0; |
| default: |
| return -1; |
| } |
| if (l >= buf_size) |
| return 0; |
| buf[l] = 0; |
| origin = buf; |
| } else { |
| origin = p->name; |
| } |
| t = strrchr(origin, '/'); |
| if (t) { |
| l = t-origin; |
| } else { |
| /* Normally p->name will always be an absolute or relative |
| * pathname containing at least one '/' character, but in the |
| * case where ldso was invoked as a command to execute a |
| * program in the working directory, app.name may not. Fix. */ |
| origin = "."; |
| l = 1; |
| } |
| /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */ |
| if (libc.secure && *origin != '/') |
| return 0; |
| p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1); |
| if (!p->rpath) return -1; |
| |
| d = p->rpath; |
| s = p->rpath_orig; |
| while ((t=strchr(s, '$'))) { |
| memcpy(d, s, t-s); |
| d += t-s; |
| memcpy(d, origin, l); |
| d += l; |
| /* It was determined previously that the '$' is followed |
| * either by "ORIGIN" or "{ORIGIN}". */ |
| s = t + 7 + 2*(t[1]=='{'); |
| } |
| strcpy(d, s); |
| return 0; |
| } |
| |
| static void decode_dyn(struct dso *p) |
| { |
| size_t dyn[DYN_CNT]; |
| decode_vec(p->dynv, dyn, DYN_CNT); |
| p->syms = laddr(p, dyn[DT_SYMTAB]); |
| p->strings = laddr(p, dyn[DT_STRTAB]); |
| if (dyn[0]&(1<<DT_HASH)) |
| p->hashtab = laddr(p, dyn[DT_HASH]); |
| if (dyn[0]&(1<<DT_RPATH)) |
| p->rpath_orig = p->strings + dyn[DT_RPATH]; |
| if (dyn[0]&(1<<DT_RUNPATH)) |
| p->rpath_orig = p->strings + dyn[DT_RUNPATH]; |
| if (dyn[0]&(1<<DT_PLTGOT)) |
| p->got = laddr(p, dyn[DT_PLTGOT]); |
| if (search_vec(p->dynv, dyn, DT_GNU_HASH)) |
| p->ghashtab = laddr(p, *dyn); |
| if (search_vec(p->dynv, dyn, DT_VERSYM)) |
| p->versym = laddr(p, *dyn); |
| } |
| |
| static size_t count_syms(struct dso *p) |
| { |
| if (p->hashtab) return p->hashtab[1]; |
| |
| size_t nsym, i; |
| uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4); |
| uint32_t *hashval; |
| for (i = nsym = 0; i < p->ghashtab[0]; i++) { |
| if (buckets[i] > nsym) |
| nsym = buckets[i]; |
| } |
| if (nsym) { |
| hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]); |
| do nsym++; |
| while (!(*hashval++ & 1)); |
| } |
| return nsym; |
| } |
| |
| static void *dl_mmap(size_t n) |
| { |
| void *p; |
| int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE; |
| #ifdef SYS_mmap2 |
| p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0); |
| #else |
| p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0); |
| #endif |
| return (unsigned long)p > -4096UL ? 0 : p; |
| } |
| |
| static void makefuncdescs(struct dso *p) |
| { |
| static int self_done; |
| size_t nsym = count_syms(p); |
| size_t i, size = nsym * sizeof(*p->funcdescs); |
| |
| if (!self_done) { |
| p->funcdescs = dl_mmap(size); |
| self_done = 1; |
| } else { |
| p->funcdescs = malloc(size); |
| } |
| if (!p->funcdescs) { |
| if (!runtime) a_crash(); |
| error("Error allocating function descriptors for %s", p->name); |
| longjmp(*rtld_fail, 1); |
| } |
| for (i=0; i<nsym; i++) { |
| if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) { |
| p->funcdescs[i].addr = laddr(p, p->syms[i].st_value); |
| p->funcdescs[i].got = p->got; |
| } else { |
| p->funcdescs[i].addr = 0; |
| p->funcdescs[i].got = 0; |
| } |
| } |
| } |
| |
| static struct dso *load_library(const char *name, struct dso *needed_by) |
| { |
| char buf[2*NAME_MAX+2]; |
| const char *pathname; |
| unsigned char *map; |
| struct dso *p, temp_dso = {0}; |
| int fd; |
| struct stat st; |
| size_t alloc_size; |
| int n_th = 0; |
| int is_self = 0; |
| |
| if (!*name) { |
| errno = EINVAL; |
| return 0; |
| } |
| |
| /* Catch and block attempts to reload the implementation itself */ |
| if (name[0]=='l' && name[1]=='i' && name[2]=='b') { |
| static const char reserved[] = |
| "c.pthread.rt.m.dl.util.xnet."; |
| const char *rp, *next; |
| for (rp=reserved; *rp; rp=next) { |
| next = strchr(rp, '.') + 1; |
| if (strncmp(name+3, rp, next-rp) == 0) |
| break; |
| } |
| if (*rp) { |
| if (ldd_mode) { |
| /* Track which names have been resolved |
| * and only report each one once. */ |
| static unsigned reported; |
| unsigned mask = 1U<<(rp-reserved); |
| if (!(reported & mask)) { |
| reported |= mask; |
| dprintf(1, "\t%s => %s (%p)\n", |
| name, ldso.name, |
| ldso.base); |
| } |
| } |
| is_self = 1; |
| } |
| } |
| if (!strcmp(name, ldso.name)) is_self = 1; |
| if (is_self) { |
| if (!ldso.prev) { |
| tail->next = &ldso; |
| ldso.prev = tail; |
| tail = &ldso; |
| } |
| return &ldso; |
| } |
| if (strchr(name, '/')) { |
| pathname = name; |
| fd = open(name, O_RDONLY|O_CLOEXEC); |
| } else { |
| /* Search for the name to see if it's already loaded */ |
| for (p=head->next; p; p=p->next) { |
| if (p->shortname && !strcmp(p->shortname, name)) { |
| return p; |
| } |
| } |
| if (strlen(name) > NAME_MAX) return 0; |
| fd = -1; |
| if (env_path) fd = path_open(name, env_path, buf, sizeof buf); |
| for (p=needed_by; fd == -1 && p; p=p->needed_by) { |
| if (fixup_rpath(p, buf, sizeof buf) < 0) |
| fd = -2; /* Inhibit further search. */ |
| if (p->rpath) |
| fd = path_open(name, p->rpath, buf, sizeof buf); |
| } |
| if (fd == -1) { |
| if (!sys_path) { |
| char *prefix = 0; |
| size_t prefix_len; |
| if (ldso.name[0]=='/') { |
| char *s, *t, *z; |
| for (s=t=z=ldso.name; *s; s++) |
| if (*s=='/') z=t, t=s; |
| prefix_len = z-ldso.name; |
| if (prefix_len < PATH_MAX) |
| prefix = ldso.name; |
| } |
| if (!prefix) { |
| prefix = ""; |
| prefix_len = 0; |
| } |
| char etc_ldso_path[prefix_len + 1 |
| + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"]; |
| snprintf(etc_ldso_path, sizeof etc_ldso_path, |
| "%.*s/etc/ld-musl-" LDSO_ARCH ".path", |
| (int)prefix_len, prefix); |
| 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 = ""; |
| } |
| close(fd); |
| } else if (errno != ENOENT) { |
| sys_path = ""; |
| } |
| } |
| if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib"; |
| fd = path_open(name, sys_path, buf, sizeof buf); |
| } |
| pathname = buf; |
| } |
| if (fd < 0) return 0; |
| if (fstat(fd, &st) < 0) { |
| close(fd); |
| return 0; |
| } |
| for (p=head->next; p; p=p->next) { |
| if (p->dev == st.st_dev && p->ino == st.st_ino) { |
| /* If this library was previously loaded with a |
| * pathname but a search found the same inode, |
| * setup its shortname so it can be found by name. */ |
| if (!p->shortname && pathname != name) |
| p->shortname = strrchr(p->name, '/')+1; |
| close(fd); |
| return p; |
| } |
| } |
| map = noload ? 0 : map_library(fd, &temp_dso); |
| close(fd); |
| if (!map) return 0; |
| |
| /* Avoid the danger of getting two versions of libc mapped into the |
| * same process when an absolute pathname was used. The symbols |
| * checked are chosen to catch both musl and glibc, and to avoid |
| * false positives from interposition-hack libraries. */ |
| decode_dyn(&temp_dso); |
| if (find_sym(&temp_dso, "__libc_start_main", 1).sym && |
| find_sym(&temp_dso, "stdin", 1).sym) { |
| unmap_library(&temp_dso); |
| return load_library("libc.so", needed_by); |
| } |
| /* Past this point, if we haven't reached runtime yet, ldso has |
| * committed either to use the mapped library or to abort execution. |
| * Unmapping is not possible, so we can safely reclaim gaps. */ |
| if (!runtime) reclaim_gaps(&temp_dso); |
| |
| /* 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) { |
| unmap_library(&temp_dso); |
| return 0; |
| } |
| memcpy(p, &temp_dso, sizeof temp_dso); |
| p->dev = st.st_dev; |
| 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; |
| if (p->tls.image) { |
| p->tls_id = ++tls_cnt; |
| tls_align = MAXP2(tls_align, p->tls.align); |
| #ifdef TLS_ABOVE_TP |
| 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) |
| & (p->tls.align-1); |
| p->tls.offset = tls_offset; |
| #endif |
| 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)); |
| if (tls_tail) tls_tail->next = &p->tls; |
| else libc.tls_head = &p->tls; |
| tls_tail = &p->tls; |
| } |
| |
| tail->next = p; |
| p->prev = tail; |
| tail = p; |
| |
| if (DL_FDPIC) makefuncdescs(p); |
| |
| if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base); |
| |
| 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) |
| { |
| 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; |
| } |
| p->bfs_built = 1; |
| for (p=head; p; p=p->next) |
| p->mark = 0; |
| } |
| |
| static void load_preload(char *s) |
| { |
| int tmp; |
| char *z; |
| for (z=s; *z; s=z) { |
| for ( ; *s && (isspace(*s) || *s==':'); s++); |
| for (z=s; *z && !isspace(*z) && *z!=':'; z++); |
| tmp = *z; |
| *z = 0; |
| load_library(s, 0); |
| *z = tmp; |
| } |
| } |
| |
| static void add_syms(struct dso *p) |
| { |
| if (!p->syms_next && syms_tail != p) { |
| syms_tail->syms_next = p; |
| syms_tail = p; |
| } |
| } |
| |
| static void revert_syms(struct dso *old_tail) |
| { |
| struct dso *p, *next; |
| /* Chop off the tail of the list of dsos that participate in |
| * the global symbol table, reverting them to RTLD_LOCAL. */ |
| for (p=old_tail; p; p=next) { |
| next = p->syms_next; |
| p->syms_next = 0; |
| } |
| syms_tail = old_tail; |
| } |
| |
| static void do_mips_relocs(struct dso *p, size_t *got) |
| { |
| size_t i, j, rel[2]; |
| unsigned char *base = p->base; |
| i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO); |
| if (p==&ldso) { |
| got += i; |
| } else { |
| while (i--) *got++ += (size_t)base; |
| } |
| j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM); |
| i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO); |
| Sym *sym = p->syms + j; |
| rel[0] = (unsigned char *)got - base; |
| for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) { |
| rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT); |
| do_relocs(p, rel, sizeof rel, 2); |
| } |
| } |
| |
| static void reloc_all(struct dso *p) |
| { |
| size_t dyn[DYN_CNT]; |
| for (; p; p=p->next) { |
| if (p->relocated) continue; |
| decode_vec(p->dynv, dyn, DYN_CNT); |
| if (NEED_MIPS_GOT_RELOCS) |
| do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT])); |
| do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ], |
| 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 (!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; |
| } |
| } |
| |
| static void kernel_mapped_dso(struct dso *p) |
| { |
| size_t min_addr = -1, max_addr = 0, cnt; |
| Phdr *ph = p->phdr; |
| for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) { |
| if (ph->p_type == PT_DYNAMIC) { |
| p->dynv = laddr(p, ph->p_vaddr); |
| } else if (ph->p_type == PT_GNU_RELRO) { |
| p->relro_start = ph->p_vaddr & -PAGE_SIZE; |
| p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE; |
| } else if (ph->p_type == PT_GNU_STACK) { |
| if (!runtime && ph->p_memsz > __default_stacksize) { |
| __default_stacksize = |
| ph->p_memsz < DEFAULT_STACK_MAX ? |
| ph->p_memsz : DEFAULT_STACK_MAX; |
| } |
| } |
| if (ph->p_type != PT_LOAD) continue; |
| if (ph->p_vaddr < min_addr) |
| min_addr = ph->p_vaddr; |
| if (ph->p_vaddr+ph->p_memsz > max_addr) |
| max_addr = ph->p_vaddr+ph->p_memsz; |
| } |
| min_addr &= -PAGE_SIZE; |
| max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE; |
| p->map = p->base + min_addr; |
| p->map_len = max_addr - min_addr; |
| p->kernel_mapped = 1; |
| } |
| |
| 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)) { |
| size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t); |
| size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n; |
| while (n--) ((void (*)(void))*--fn)(); |
| } |
| #ifndef NO_LEGACY_INITFINI |
| if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI]) |
| fpaddr(p, dyn[DT_FINI])(); |
| #endif |
| } |
| } |
| |
| void __ldso_atfork(int who) |
| { |
| 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])(); |
| #endif |
| if (dyn[0] & (1<<DT_INIT_ARRAY)) { |
| size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t); |
| size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]); |
| while (n--) ((void (*)(void))*fn++)(); |
| } |
| |
| pthread_mutex_lock(&init_fini_lock); |
| p->ctor_visitor = 0; |
| p->constructed = 1; |
| pthread_cond_broadcast(&ctor_cond); |
| } |
| pthread_mutex_unlock(&init_fini_lock); |
| } |
| |
| void __libc_start_init(void) |
| { |
| 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) |
| { |
| } |
| |
| weak_alias(dl_debug_state, _dl_debug_state); |
| |
| void __init_tls(size_t *auxv) |
| { |
| } |
| |
| static void update_tls_size() |
| { |
| libc.tls_cnt = tls_cnt; |
| libc.tls_align = tls_align; |
| libc.tls_size = ALIGN( |
| (1+tls_cnt) * sizeof(void *) + |
| tls_offset + |
| sizeof(struct pthread) + |
| tls_align * 2, |
| 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. */ |
| |
| /* Stage 2 of the dynamic linker is called after relative relocations |
| * have been processed. It can make function calls to static functions |
| * and access string literals and static data, but cannot use extern |
| * symbols. Its job is to perform symbolic relocations on the dynamic |
| * linker itself, but some of the relocations performed may need to be |
| * replaced later due to copy relocations in the main program. */ |
| |
| 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 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); |
| } |
| app_loadmap = p2 ? p1 : 0; |
| ldso.loadmap = p2 ? p2 : p1; |
| ldso.base = laddr(&ldso, 0); |
| } else { |
| ldso.base = 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); |
| |
| if (DL_FDPIC) makefuncdescs(&ldso); |
| |
| /* Prepare storage for to save clobbered REL addends so they |
| * can be reused in stage 3. There should be very few. If |
| * something goes wrong and there are a huge number, abort |
| * instead of risking stack overflow. */ |
| size_t dyn[DYN_CNT]; |
| decode_vec(ldso.dynv, dyn, DYN_CNT); |
| size_t *rel = laddr(&ldso, dyn[DT_REL]); |
| size_t rel_size = dyn[DT_RELSZ]; |
| size_t symbolic_rel_cnt = 0; |
| apply_addends_to = rel; |
| for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t)) |
| if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++; |
| if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash(); |
| size_t addends[symbolic_rel_cnt+1]; |
| saved_addends = addends; |
| |
| head = &ldso; |
| reloc_all(&ldso); |
| |
| ldso.relocated = 0; |
| |
| /* Call dynamic linker stage-2b, __dls2b, looking it up |
| * 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, auxv); |
| else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp, auxv); |
| } |
| |
| /* Stage 2b sets up a valid thread pointer, which requires relocations |
| * completed in stage 2, and on which stage 3 is permitted to depend. |
| * This is done as a separate stage, with symbolic lookup as a barrier, |
| * so that loads of the thread pointer and &errno can be pure/const and |
| * thereby hoistable. */ |
| |
| 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) { |
| a_crash(); |
| } |
| |
| struct symdef dls3_def = find_sym(&ldso, "__dls3", 0); |
| 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 |
| * fully functional. Its job is to load (if not already loaded) and |
| * process dependencies and relocations for the main application and |
| * transfer control to its entry point. */ |
| |
| void __dls3(size_t *sp, size_t *auxv) |
| { |
| static struct dso app, vdso; |
| size_t aux[AUX_CNT]; |
| size_t i; |
| char *env_preload=0; |
| char *replace_argv0=0; |
| size_t vdso_base; |
| int argc = *sp; |
| char **argv = (void *)(sp+1); |
| char **argv_orig = argv; |
| char **envp = argv+argc+1; |
| |
| /* Find aux vector just past environ[] and use it to initialize |
| * global data that may be needed before we can make syscalls. */ |
| __environ = envp; |
| decode_vec(auxv, aux, AUX_CNT); |
| 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]); |
| |
| /* Only trust user/env if kernel says we're not suid/sgid */ |
| if (!libc.secure) { |
| env_path = getenv("LD_LIBRARY_PATH"); |
| 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. */ |
| if (aux[AT_PHDR] != (size_t)ldso.phdr) { |
| size_t interp_off = 0; |
| size_t tls_image = 0; |
| /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */ |
| Phdr *phdr = app.phdr = (void *)aux[AT_PHDR]; |
| app.phnum = aux[AT_PHNUM]; |
| app.phentsize = aux[AT_PHENT]; |
| for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) { |
| if (phdr->p_type == PT_PHDR) |
| app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr); |
| else if (phdr->p_type == PT_INTERP) |
| interp_off = (size_t)phdr->p_vaddr; |
| else if (phdr->p_type == PT_TLS) { |
| tls_image = phdr->p_vaddr; |
| app.tls.len = phdr->p_filesz; |
| app.tls.size = phdr->p_memsz; |
| app.tls.align = phdr->p_align; |
| } |
| } |
| if (DL_FDPIC) app.loadmap = app_loadmap; |
| if (app.tls.size) app.tls.image = laddr(&app, tls_image); |
| if (interp_off) ldso.name = laddr(&app, interp_off); |
| if ((aux[0] & (1UL<<AT_EXECFN)) |
| && strncmp((char *)aux[AT_EXECFN], "/proc/", 6)) |
| app.name = (char *)aux[AT_EXECFN]; |
| else |
| app.name = argv[0]; |
| kernel_mapped_dso(&app); |
| } else { |
| int fd; |
| char *ldname = argv[0]; |
| size_t l = strlen(ldname); |
| if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1; |
| argv++; |
| while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') { |
| char *opt = argv[0]+2; |
| *argv++ = (void *)-1; |
| if (!*opt) { |
| break; |
| } else if (!memcmp(opt, "list", 5)) { |
| ldd_mode = 1; |
| } else if (!memcmp(opt, "library-path", 12)) { |
| if (opt[12]=='=') env_path = opt+13; |
| else if (opt[12]) *argv = 0; |
| else if (*argv) env_path = *argv++; |
| } else if (!memcmp(opt, "preload", 7)) { |
| if (opt[7]=='=') env_preload = opt+8; |
| else if (opt[7]) *argv = 0; |
| else if (*argv) env_preload = *argv++; |
| } else if (!memcmp(opt, "argv0", 5)) { |
| if (opt[5]=='=') replace_argv0 = opt+6; |
| else if (opt[5]) *argv = 0; |
| else if (*argv) replace_argv0 = *argv++; |
| } else { |
| argv[0] = 0; |
| } |
| } |
| argv[-1] = (void *)(argc - (argv-argv_orig)); |
| if (!argv[0]) { |
| dprintf(2, "musl libc (" LDSO_ARCH ")\n" |
| "Version %s\n" |
| "Dynamic Program Loader\n" |
| "Usage: %s [options] [--] pathname%s\n", |
| __libc_version, ldname, |
| ldd_mode ? "" : " [args]"); |
| _exit(1); |
| } |
| fd = open(argv[0], O_RDONLY); |
| if (fd < 0) { |
| dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno)); |
| _exit(1); |
| } |
| Ehdr *ehdr = map_library(fd, &app); |
| if (!ehdr) { |
| dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]); |
| _exit(1); |
| } |
| close(fd); |
| ldso.name = ldname; |
| app.name = argv[0]; |
| aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry); |
| /* Find the name that would have been used for the dynamic |
| * linker had ldd not taken its place. */ |
| if (ldd_mode) { |
| for (i=0; i<app.phnum; i++) { |
| if (app.phdr[i].p_type == PT_INTERP) |
| ldso.name = laddr(&app, app.phdr[i].p_vaddr); |
| } |
| dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base); |
| } |
| } |
| if (app.tls.size) { |
| libc.tls_head = tls_tail = &app.tls; |
| app.tls_id = tls_cnt = 1; |
| #ifdef TLS_ABOVE_TP |
| app.tls.offset = GAP_ABOVE_TP; |
| 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) |
| & (app.tls.align-1) ); |
| #endif |
| tls_align = MAXP2(tls_align, app.tls.align); |
| } |
| decode_dyn(&app); |
| if (DL_FDPIC) { |
| makefuncdescs(&app); |
| if (!app.loadmap) { |
| app.loadmap = (void *)&app_dummy_loadmap; |
| app.loadmap->nsegs = 1; |
| app.loadmap->segs[0].addr = (size_t)app.map; |
| app.loadmap->segs[0].p_vaddr = (size_t)app.map |
| - (size_t)app.base; |
| app.loadmap->segs[0].p_memsz = app.map_len; |
| } |
| argv[-3] = (void *)app.loadmap; |
| } |
| |
| /* Initial dso chain consists only of the app. */ |
| head = tail = syms_tail = &app; |
| |
| /* Donate unused parts of app and library mapping to malloc */ |
| reclaim_gaps(&app); |
| 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) |
| add_syms(p); |
| |
| /* Attach to vdso, if provided by the kernel, last so that it does |
| * not become part of the global namespace. */ |
| if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) { |
| Ehdr *ehdr = (void *)vdso_base; |
| Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff); |
| vdso.phnum = ehdr->e_phnum; |
| vdso.phentsize = ehdr->e_phentsize; |
| for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) { |
| if (phdr->p_type == PT_DYNAMIC) |
| vdso.dynv = (void *)(vdso_base + phdr->p_offset); |
| if (phdr->p_type == PT_LOAD) |
| vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset); |
| } |
| 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; |
| tail = &vdso; |
| } |
| |
| for (i=0; app.dynv[i]; i+=2) { |
| if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG) |
| app.dynv[i+1] = (size_t)&debug; |
| if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) { |
| 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; |
| } |
| } |
| |
| /* 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) { |
| 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(); |
| } |
| } else { |
| size_t tmp_tls_size = libc.tls_size; |
| pthread_t self = __pthread_self(); |
| /* Temporarily set the tls size to the full size of |
| * builtin_tls so that __copy_tls will use the same layout |
| * as it did for before. Then check, just to be safe. */ |
| libc.tls_size = sizeof builtin_tls; |
| if (__copy_tls((void*)builtin_tls) != self) a_crash(); |
| libc.tls_size = tmp_tls_size; |
| } |
| |
| if (ldso_fail) _exit(127); |
| if (ldd_mode) _exit(0); |
| |
| /* Determine if malloc was interposed by a replacement implementation |
| * so that calloc and the memalign family can harden against the |
| * 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 |
| * error. */ |
| runtime = 1; |
| |
| debug.ver = 1; |
| debug.bp = dl_debug_state; |
| debug.head = head; |
| debug.base = ldso.base; |
| debug.state = RT_CONSISTENT; |
| _dl_debug_state(); |
| |
| if (replace_argv0) argv[0] = replace_argv0; |
| |
| errno = 0; |
| |
| CRTJMP((void *)aux[AT_ENTRY], argv-1); |
| for(;;); |
| } |
| |
| static void prepare_lazy(struct dso *p) |
| { |
| size_t dyn[DYN_CNT], n, flags1=0; |
| decode_vec(p->dynv, dyn, DYN_CNT); |
| search_vec(p->dynv, &flags1, DT_FLAGS_1); |
| if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW)) |
| return; |
| n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1; |
| if (NEED_MIPS_GOT_RELOCS) { |
| size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM); |
| size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO); |
| n += i-j; |
| } |
| p->lazy = calloc(n, 3*sizeof(size_t)); |
| if (!p->lazy) { |
| error("Error preparing lazy relocation for %s: %m", p->name); |
| longjmp(*rtld_fail, 1); |
| } |
| p->lazy_next = lazy_head; |
| lazy_head = p; |
| } |
| |
| void *dlopen(const char *file, int mode) |
| { |
| struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next; |
| struct tls_module *orig_tls_tail; |
| size_t orig_tls_cnt, orig_tls_offset, orig_tls_align; |
| size_t i; |
| int cs; |
| jmp_buf jb; |
| struct dso **volatile ctor_queue = 0; |
| |
| if (!file) return head; |
| |
| pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); |
| 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; |
| orig_tls_align = tls_align; |
| orig_lazy_head = lazy_head; |
| orig_syms_tail = syms_tail; |
| orig_tail = tail; |
| noload = mode & RTLD_NOLOAD; |
| |
| rtld_fail = &jb; |
| if (setjmp(*rtld_fail)) { |
| /* Clean up anything new that was (partially) loaded */ |
| revert_syms(orig_syms_tail); |
| for (p=orig_tail->next; p; p=next) { |
| next = p->next; |
| while (p->td_index) { |
| void *tmp = p->td_index->next; |
| free(p->td_index); |
| p->td_index = tmp; |
| } |
| free(p->funcdescs); |
| if (p->rpath != p->rpath_orig) |
| free(p->rpath); |
| 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; |
| tls_cnt = orig_tls_cnt; |
| tls_offset = orig_tls_offset; |
| tls_align = orig_tls_align; |
| lazy_head = orig_lazy_head; |
| tail = orig_tail; |
| tail->next = 0; |
| p = 0; |
| goto end; |
| } else p = load_library(file, head); |
| |
| if (!p) { |
| error(noload ? |
| "Library %s is not already loaded" : |
| "Error loading shared library %s: %m", |
| file); |
| goto end; |
| } |
| |
| /* First load handling */ |
| 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 (!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 (!p->relocated) { |
| reloc_all(p); |
| } |
| |
| /* If RTLD_GLOBAL was not specified, undo any new additions |
| * to the global symbol table. This is a nop if the library was |
| * previously loaded and already global. */ |
| if (!(mode & RTLD_GLOBAL)) |
| revert_syms(orig_syms_tail); |
| |
| /* Processing of deferred lazy relocations must not happen until |
| * the new libraries are committed; otherwise we could end up with |
| * relocations resolved to symbol definitions that get removed. */ |
| redo_lazy_relocs(); |
| |
| update_tls_size(); |
| 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 (ctor_queue) { |
| do_init_fini(ctor_queue); |
| free(ctor_queue); |
| } |
| pthread_setcancelstate(cs, 0); |
| return p; |
| } |
| |
| hidden int __dl_invalid_handle(void *h) |
| { |
| struct dso *p; |
| for (p=head; p; p=p->next) if (h==p) return 0; |
| error("Invalid library handle %p", (void *)h); |
| return 1; |
| } |
| |
| static void *addr2dso(size_t a) |
| { |
| struct dso *p; |
| size_t i; |
| if (DL_FDPIC) for (p=head; p; p=p->next) { |
| i = count_syms(p); |
| if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs)) |
| return p; |
| } |
| for (p=head; p; p=p->next) { |
| if (DL_FDPIC && p->loadmap) { |
| for (i=0; i<p->loadmap->nsegs; i++) { |
| if (a-p->loadmap->segs[i].p_vaddr |
| < p->loadmap->segs[i].p_memsz) |
| return p; |
| } |
| } else { |
| Phdr *ph = p->phdr; |
| size_t phcnt = p->phnum; |
| size_t entsz = p->phentsize; |
| size_t base = (size_t)p->base; |
| for (; phcnt--; ph=(void *)((char *)ph+entsz)) { |
| if (ph->p_type != PT_LOAD) continue; |
| if (a-base-ph->p_vaddr < ph->p_memsz) |
| return p; |
| } |
| if (a-(size_t)p->map < p->map_len) |
| return 0; |
| } |
| } |
| return 0; |
| } |
| |
| static void *do_dlsym(struct dso *p, const char *s, void *ra) |
| { |
| 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 ((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) |
| { |
| size_t addr = (size_t)addr_arg; |
| struct dso *p; |
| Sym *sym, *bestsym; |
| uint32_t nsym; |
| char *strings; |
| size_t best = 0; |
| size_t besterr = -1; |
| |
| pthread_rwlock_rdlock(&lock); |
| p = addr2dso(addr); |
| pthread_rwlock_unlock(&lock); |
| |
| if (!p) return 0; |
| |
| sym = p->syms; |
| strings = p->strings; |
| nsym = count_syms(p); |
| |
| if (DL_FDPIC) { |
| size_t idx = (addr-(size_t)p->funcdescs) |
| / sizeof(*p->funcdescs); |
| if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) { |
| best = (size_t)(p->funcdescs + idx); |
| bestsym = sym + idx; |
| besterr = 0; |
| } |
| } |
| |
| if (!best) for (; nsym; nsym--, sym++) { |
| if (sym->st_value |
| && (1<<(sym->st_info&0xf) & OK_TYPES) |
| && (1<<(sym->st_info>>4) & OK_BINDS)) { |
| size_t symaddr = (size_t)laddr(p, sym->st_value); |
| if (symaddr > addr || symaddr <= best) |
| continue; |
| best = symaddr; |
| bestsym = sym; |
| besterr = addr - symaddr; |
| if (addr == symaddr) |
| break; |
| } |
| } |
| |
| if (best && besterr > bestsym->st_size-1) { |
| best = 0; |
| bestsym = 0; |
| } |
| |
| info->dli_fname = p->name; |
| info->dli_fbase = p->map; |
| |
| if (!best) { |
| info->dli_sname = 0; |
| info->dli_saddr = 0; |
| return 1; |
| } |
| |
| if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC) |
| best = (size_t)(p->funcdescs + (bestsym - p->syms)); |
| info->dli_sname = strings + bestsym->st_name; |
| info->dli_saddr = (void *)best; |
| |
| return 1; |
| } |
| |
| hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra) |
| { |
| void *res; |
| pthread_rwlock_rdlock(&lock); |
| res = do_dlsym(p, s, ra); |
| pthread_rwlock_unlock(&lock); |
| 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; |
| struct dl_phdr_info info; |
| int ret = 0; |
| for(current = head; current;) { |
| info.dlpi_addr = (uintptr_t)current->base; |
| info.dlpi_name = current->name; |
| info.dlpi_phdr = current->phdr; |
| info.dlpi_phnum = current->phnum; |
| info.dlpi_adds = gencnt; |
| info.dlpi_subs = 0; |
| info.dlpi_tls_modid = current->tls_id; |
| 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); |
| |
| if (ret != 0) break; |
| |
| pthread_rwlock_rdlock(&lock); |
| current = current->next; |
| pthread_rwlock_unlock(&lock); |
| } |
| return ret; |
| } |
| |
| static void error_impl(const char *fmt, ...) |
| { |
| va_list ap; |
| va_start(ap, fmt); |
| if (!runtime) { |
| vdprintf(2, fmt, ap); |
| dprintf(2, "\n"); |
| ldso_fail = 1; |
| va_end(ap); |
| return; |
| } |
| __dl_vseterr(fmt, ap); |
| va_end(ap); |
| } |
| |
| static void error_noop(const char *fmt, ...) |
| { |
| } |