diff options
Diffstat (limited to 'libc-top-half/musl/ldso')
| -rw-r--r-- | libc-top-half/musl/ldso/dlstart.c | 148 | ||||
| -rw-r--r-- | libc-top-half/musl/ldso/dynlink.c | 2361 |
2 files changed, 2509 insertions, 0 deletions
diff --git a/libc-top-half/musl/ldso/dlstart.c b/libc-top-half/musl/ldso/dlstart.c new file mode 100644 index 0000000..20d50f2 --- /dev/null +++ b/libc-top-half/musl/ldso/dlstart.c @@ -0,0 +1,148 @@ +#include <stddef.h> +#include "dynlink.h" +#include "libc.h" + +#ifndef START +#define START "_dlstart" +#endif + +#define SHARED + +#include "crt_arch.h" + +#ifndef GETFUNCSYM +#define GETFUNCSYM(fp, sym, got) do { \ + hidden void sym(); \ + static void (*static_func_ptr)() = sym; \ + __asm__ __volatile__ ( "" : "+m"(static_func_ptr) : : "memory"); \ + *(fp) = static_func_ptr; } while(0) +#endif + +hidden void _dlstart_c(size_t *sp, size_t *dynv) +{ + size_t i, aux[AUX_CNT], dyn[DYN_CNT]; + size_t *rel, rel_size, base; + + int argc = *sp; + char **argv = (void *)(sp+1); + + for (i=argc+1; argv[i]; i++); + size_t *auxv = (void *)(argv+i+1); + + for (i=0; i<AUX_CNT; i++) aux[i] = 0; + for (i=0; auxv[i]; i+=2) if (auxv[i]<AUX_CNT) + aux[auxv[i]] = auxv[i+1]; + +#if DL_FDPIC + struct fdpic_loadseg *segs, fakeseg; + size_t j; + if (dynv) { + /* crt_arch.h entry point asm is responsible for reserving + * space and moving the extra fdpic arguments to the stack + * vector where they are easily accessible from C. */ + segs = ((struct fdpic_loadmap *)(sp[-1] ? sp[-1] : sp[-2]))->segs; + } else { + /* If dynv is null, the entry point was started from loader + * that is not fdpic-aware. We can assume normal fixed- + * displacement ELF loading was performed, but when ldso was + * run as a command, finding the Ehdr is a heursitic: we + * have to assume Phdrs start in the first 4k of the file. */ + base = aux[AT_BASE]; + if (!base) base = aux[AT_PHDR] & -4096; + segs = &fakeseg; + segs[0].addr = base; + segs[0].p_vaddr = 0; + segs[0].p_memsz = -1; + Ehdr *eh = (void *)base; + Phdr *ph = (void *)(base + eh->e_phoff); + size_t phnum = eh->e_phnum; + size_t phent = eh->e_phentsize; + while (phnum-- && ph->p_type != PT_DYNAMIC) + ph = (void *)((size_t)ph + phent); + dynv = (void *)(base + ph->p_vaddr); + } +#endif + + for (i=0; i<DYN_CNT; i++) dyn[i] = 0; + for (i=0; dynv[i]; i+=2) if (dynv[i]<DYN_CNT) + dyn[dynv[i]] = dynv[i+1]; + +#if DL_FDPIC + for (i=0; i<DYN_CNT; i++) { + if (i==DT_RELASZ || i==DT_RELSZ) continue; + if (!dyn[i]) continue; + for (j=0; dyn[i]-segs[j].p_vaddr >= segs[j].p_memsz; j++); + dyn[i] += segs[j].addr - segs[j].p_vaddr; + } + base = 0; + + const Sym *syms = (void *)dyn[DT_SYMTAB]; + + rel = (void *)dyn[DT_RELA]; + rel_size = dyn[DT_RELASZ]; + for (; rel_size; rel+=3, rel_size-=3*sizeof(size_t)) { + if (!IS_RELATIVE(rel[1], syms)) continue; + for (j=0; rel[0]-segs[j].p_vaddr >= segs[j].p_memsz; j++); + size_t *rel_addr = (void *) + (rel[0] + segs[j].addr - segs[j].p_vaddr); + if (R_TYPE(rel[1]) == REL_FUNCDESC_VAL) { + *rel_addr += segs[rel_addr[1]].addr + - segs[rel_addr[1]].p_vaddr + + syms[R_SYM(rel[1])].st_value; + rel_addr[1] = dyn[DT_PLTGOT]; + } else { + size_t val = syms[R_SYM(rel[1])].st_value; + for (j=0; val-segs[j].p_vaddr >= segs[j].p_memsz; j++); + *rel_addr = rel[2] + segs[j].addr - segs[j].p_vaddr + val; + } + } +#else + /* If the dynamic linker is invoked as a command, its load + * address is not available in the aux vector. Instead, compute + * the load address as the difference between &_DYNAMIC and the + * virtual address in the PT_DYNAMIC program header. */ + base = aux[AT_BASE]; + if (!base) { + size_t phnum = aux[AT_PHNUM]; + size_t phentsize = aux[AT_PHENT]; + Phdr *ph = (void *)aux[AT_PHDR]; + for (i=phnum; i--; ph = (void *)((char *)ph + phentsize)) { + if (ph->p_type == PT_DYNAMIC) { + base = (size_t)dynv - ph->p_vaddr; + break; + } + } + } + + /* MIPS uses an ugly packed form for GOT relocations. Since we + * can't make function calls yet and the code is tiny anyway, + * it's simply inlined here. */ + if (NEED_MIPS_GOT_RELOCS) { + size_t local_cnt = 0; + size_t *got = (void *)(base + dyn[DT_PLTGOT]); + for (i=0; dynv[i]; i+=2) if (dynv[i]==DT_MIPS_LOCAL_GOTNO) + local_cnt = dynv[i+1]; + for (i=0; i<local_cnt; i++) got[i] += base; + } + + rel = (void *)(base+dyn[DT_REL]); + rel_size = dyn[DT_RELSZ]; + for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t)) { + if (!IS_RELATIVE(rel[1], 0)) continue; + size_t *rel_addr = (void *)(base + rel[0]); + *rel_addr += base; + } + + rel = (void *)(base+dyn[DT_RELA]); + rel_size = dyn[DT_RELASZ]; + for (; rel_size; rel+=3, rel_size-=3*sizeof(size_t)) { + if (!IS_RELATIVE(rel[1], 0)) continue; + size_t *rel_addr = (void *)(base + rel[0]); + *rel_addr = base + rel[2]; + } +#endif + + stage2_func dls2; + GETFUNCSYM(&dls2, __dls2, base+dyn[DT_PLTGOT]); + dls2((void *)base, sp); +} diff --git a/libc-top-half/musl/ldso/dynlink.c b/libc-top-half/musl/ldso/dynlink.c new file mode 100644 index 0000000..5b9c8be --- /dev/null +++ b/libc-top-half/musl/ldso/dynlink.c @@ -0,0 +1,2361 @@ +#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 "libc.h" +#include "dynlink.h" + +#define malloc __libc_malloc +#define calloc __libc_calloc +#define realloc __libc_realloc +#define free __libc_free + +static void error(const char *, ...); + +#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 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) { + 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 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 && (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[1]; + 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 + } +#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 + break; + default: + error("Error relocating %s: unsupported relocation type %d", + dso->name, type); + if (runtime) longjmp(*rtld_fail, 1); + continue; + } + } +} + +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, $ORIGIN can be processed safely + * since the library's pathname came from a trusted source + * (either system paths or a call to dlopen). */ + if (libc.secure) + return 0; + l = readlink("/proc/self/exe", buf, buf_size); + if (l == -1) switch (errno) { + case ENOENT: + case ENOTDIR: + case EACCES: + break; + default: + return -1; + } + if (l >= buf_size) + return 0; + buf[l] = 0; + origin = buf; + } else { + origin = p->name; + } + t = strrchr(origin, '/'); + if (t) { + l = t-origin; + } else { + /* Normally p->name will always be an absolute or relative + * pathname containing at least one '/' character, but in the + * case where ldso was invoked as a command to execute a + * program in the working directory, app.name may not. Fix. */ + origin = "."; + l = 1; + } + /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */ + if (libc.secure && *origin != '/') + return 0; + p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1); + if (!p->rpath) return -1; + + d = p->rpath; + s = p->rpath_orig; + while ((t=strchr(s, '$'))) { + 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 (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); + } + + 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 = (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; + 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"); + } + + /* 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; + } + } + + /* 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(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); +} |