diff options
Diffstat (limited to 'ldso')
| -rw-r--r-- | ldso/dlstart.c | 146 | ||||
| -rw-r--r-- | ldso/dynlink.c | 1931 |
2 files changed, 2077 insertions, 0 deletions
diff --git a/ldso/dlstart.c b/ldso/dlstart.c new file mode 100644 index 00000000..4482d525 --- /dev/null +++ b/ldso/dlstart.c @@ -0,0 +1,146 @@ +#include <stddef.h> +#include "dynlink.h" + +#ifndef START +#define START "_dlstart" +#endif + +#include "crt_arch.h" + +#ifndef GETFUNCSYM +#define GETFUNCSYM(fp, sym, got) do { \ + __attribute__((__visibility__("hidden"))) void sym(); \ + static void (*static_func_ptr)() = sym; \ + __asm__ __volatile__ ( "" : "+m"(static_func_ptr) : : "memory"); \ + *(fp) = static_func_ptr; } while(0) +#endif + +__attribute__((__visibility__("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/ldso/dynlink.c b/ldso/dynlink.c new file mode 100644 index 00000000..26a60b4c --- /dev/null +++ b/ldso/dynlink.c @@ -0,0 +1,1931 @@ +#define _GNU_SOURCE +#include <stdio.h> +#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 "pthread_impl.h" +#include "libc.h" +#include "dynlink.h" + +static void error(const char *, ...); + +#define MAXP2(a,b) (-(-(a)&-(b))) +#define ALIGN(x,y) ((x)+(y)-1 & -(y)) + +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; + int refcnt; + Sym *syms; + uint32_t *hashtab; + uint32_t *ghashtab; + int16_t *versym; + char *strings; + unsigned char *map; + size_t map_len; + dev_t dev; + ino_t ino; + signed char global; + char relocated; + char constructed; + char kernel_mapped; + struct dso **deps, *needed_by; + char *rpath_orig, *rpath; + struct tls_module tls; + size_t tls_id; + size_t relro_start, relro_end; + void **new_dtv; + unsigned char *new_tls; + volatile int new_dtv_idx, new_tls_idx; + struct td_index *td_index; + struct dso *fini_next; + char *shortname; +#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; +}; + +int __init_tp(void *); +void __init_libc(char **, char *); +void *__copy_tls(unsigned char *); + +__attribute__((__visibility__("hidden"))) +const char *__libc_get_version(void); + +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; +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 jmp_buf *rtld_fail; +static pthread_rwlock_t lock; +static struct debug debug; +static struct tls_module *tls_tail; +static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN; +static size_t static_tls_cnt; +static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE }; +static struct fdpic_loadmap *app_loadmap; +static struct fdpic_dummy_loadmap app_dummy_loadmap; + +struct debug *_dl_debug_addr = &debug; + +__attribute__((__visibility__("hidden"))) +void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0; + +__attribute__((__visibility__("hidden"))) +extern 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); +} +#define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \ + laddr(p, v), (p)->got }) +#else +#define laddr(p, v) (void *)((p)->base + (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; + uint32_t *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 + +static struct symdef find_sym(struct dso *dso, const char *s, int need_def) +{ + uint32_t h = 0, gh, gho, *ght; + size_t ghm = 0; + struct symdef def = {0}; + for (; dso; dso=dso->next) { + Sym *sym; + if (!dso->global) continue; + if ((ght = dso->ghashtab)) { + if (!ghm) { + gh = gnu_hash(s); + int maskbits = 8 * sizeof ghm; + gho = gh / maskbits; + ghm = 1ul << gh % maskbits; + } + 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; + + if (def.sym && sym->st_info>>4 == STB_WEAK) continue; + def.sym = sym; + def.dso = dso; + if (sym->st_info>>4 == STB_GLOBAL) break; + } + return def; +} + +__attribute__((__visibility__("hidden"))) +ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic(); + +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; + sym_index = R_SYM(rel[1]); + reloc_addr = laddr(dso, rel[0]); + if (sym_index) { + sym = syms + sym_index; + name = strings + sym->st_name; + ctx = type==REL_COPY ? head->next : head; + def = (sym->st_info&0xf) == STT_SECTION + ? (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)) { + 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; + } + + 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_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0; + tls_val = def.sym ? def.sym->st_value : 0; + + switch(type) { + case REL_NONE: + break; + 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_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 (runtime && 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; + 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 + } + break; + default: + error("Error relocating %s: unsupported relocation type %d", + dso->name, type); + if (runtime) longjmp(*rtld_fail, 1); + continue; + } + } +} + +/* 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 by setting up minimal malloc + * structures and then freeing them. */ + +static void reclaim(struct dso *dso, size_t start, size_t end) +{ + size_t *a, *z; + 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; + start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t); + end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t); + if (start>end || end-start < 4*sizeof(size_t)) return; + a = laddr(dso, start); + z = laddr(dso, end); + a[-2] = 1; + a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1; + z[1] = 1; + free(a); +} + +static void reclaim_gaps(struct dso *dso) +{ + Phdr *ph = dso->phdr; + size_t phcnt = dso->phnum; + + if (DL_FDPIC) return; // FIXME + 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 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 (!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; + } + 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; + } + /* Reuse the existing mapping for the lowest-address LOAD */ + if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT) + continue; + 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)); + 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) { + 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); + if (!runtime) reclaim_gaps(dso); + 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, $ORIGIN can be processed safely + * since the library's pathname came from a trusted source + * (either system paths or a call to dlopen). */ + if (libc.secure) + return 0; + l = readlink("/proc/self/exe", buf, buf_size); + if (l == -1) switch (errno) { + case ENOENT: + case ENOTDIR: + case EACCES: + break; + default: + return -1; + } + if (l >= buf_size) + return 0; + buf[l] = 0; + origin = buf; + } else { + origin = p->name; + } + t = strrchr(origin, '/'); + l = t ? t-origin : 0; + p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1); + if (!p->rpath) return -1; + + d = p->rpath; + s = p->rpath_orig; + while ((t=strchr(s, '$'))) { + 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 p == MAP_FAILED ? 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 *rp, reserved[] = + "c\0pthread\0rt\0m\0dl\0util\0xnet\0"; + char *z = strchr(name, '.'); + if (z) { + size_t l = z-name; + for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1); + 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.next ? ldso.next : &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)) { + p->refcnt++; + 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); + FILE *f = fopen(etc_ldso_path, "rbe"); + if (f) { + if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) { + free(sys_path); + sys_path = ""; + } + fclose(f); + } 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); + p->refcnt++; + return p; + } + } + map = noload ? 0 : map_library(fd, &temp_dso); + close(fd); + if (!map) return 0; + + /* 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); + decode_dyn(p); + p->dev = st.st_dev; + p->ino = st.st_ino; + p->refcnt = 1; + p->needed_by = needed_by; + p->name = p->buf; + 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 + ( (tls_align-1) & + -(tls_offset + (uintptr_t)p->tls.image) ); + 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_deps(struct dso *p) +{ + size_t i, ndeps=0; + struct dso ***deps = &p->deps, **tmp, *dep; + for (; p; p=p->next) { + for (i=0; p->dynv[i]; i+=2) { + if (p->dynv[i] != DT_NEEDED) continue; + dep = load_library(p->strings + p->dynv[i+1], p); + if (!dep) { + error("Error loading shared library %s: %m (needed by %s)", + p->strings + p->dynv[i+1], p->name); + if (runtime) longjmp(*rtld_fail, 1); + continue; + } + if (runtime) { + tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2)); + if (!tmp) longjmp(*rtld_fail, 1); + tmp[ndeps++] = dep; + tmp[ndeps] = 0; + *deps = tmp; + } + } + } +} + +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 make_global(struct dso *p) +{ + for (; p; p=p->next) p->global = 1; +} + +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] = sym-p->syms << 8 | 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; + } + 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]; + for (p=fini_head; p; p=p->fini_next) { + 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 + } +} + +static void do_init_fini(struct dso *p) +{ + size_t dyn[DYN_CNT]; + int need_locking = libc.threads_minus_1; + /* Allow recursive calls that arise when a library calls + * dlopen from one of its constructors, but block any + * other threads until all ctors have finished. */ + if (need_locking) pthread_mutex_lock(&init_fini_lock); + for (; p; p=p->prev) { + if (p->constructed) continue; + p->constructed = 1; + 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; + } +#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++)(); + } + if (!need_locking && libc.threads_minus_1) { + need_locking = 1; + pthread_mutex_lock(&init_fini_lock); + } + } + if (need_locking) pthread_mutex_unlock(&init_fini_lock); +} + +void __libc_start_init(void) +{ + do_init_fini(tail); +} + +static void dl_debug_state(void) +{ +} + +weak_alias(dl_debug_state, _dl_debug_state); + +void __init_tls(size_t *auxv) +{ +} + +__attribute__((__visibility__("hidden"))) +void *__tls_get_new(size_t *v) +{ + pthread_t self = __pthread_self(); + + /* Block signals to make accessing new TLS async-signal-safe */ + sigset_t set; + __block_all_sigs(&set); + if (v[0]<=(size_t)self->dtv[0]) { + __restore_sigs(&set); + return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET; + } + + /* This is safe without any locks held because, if the caller + * is able to request the Nth entry of the DTV, the DSO list + * must be valid at least that far out and it was synchronized + * at program startup or by an already-completed call to dlopen. */ + struct dso *p; + for (p=head; p->tls_id != v[0]; p=p->next); + + /* Get new DTV space from new DSO if needed */ + if (v[0] > (size_t)self->dtv[0]) { + void **newdtv = p->new_dtv + + (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1); + memcpy(newdtv, self->dtv, + ((size_t)self->dtv[0]+1) * sizeof(void *)); + newdtv[0] = (void *)v[0]; + self->dtv = self->dtv_copy = newdtv; + } + + /* Get new TLS memory from all new DSOs up to the requested one */ + unsigned char *mem; + for (p=head; ; p=p->next) { + if (!p->tls_id || self->dtv[p->tls_id]) continue; + mem = p->new_tls + (p->tls.size + p->tls.align) + * a_fetch_add(&p->new_tls_idx,1); + mem += ((uintptr_t)p->tls.image - (uintptr_t)mem) + & (p->tls.align-1); + self->dtv[p->tls_id] = mem; + memcpy(mem, p->tls.image, p->tls.len); + if (p->tls_id == v[0]) break; + } + __restore_sigs(&set); + return mem + v[1] + DTP_OFFSET; +} + +static void update_tls_size() +{ + libc.tls_cnt = tls_cnt; + libc.tls_align = tls_align; + libc.tls_size = ALIGN( + (1+tls_cnt) * sizeof(void *) + + tls_offset + + sizeof(struct pthread) + + tls_align * 2, + tls_align); +} + +/* 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. */ + +__attribute__((__visibility__("hidden"))) +void __dls2(unsigned char *base, size_t *sp) +{ + if (DL_FDPIC) { + void *p1 = (void *)sp[-2]; + void *p2 = (void *)sp[-1]; + if (!p1) { + size_t *auxv, aux[AUX_CNT]; + for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++; + 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.global = 1; + 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-3, __dls3, looking it up + * symbolically as a barrier against moving the address + * load across the above relocation processing. */ + struct symdef dls3_def = find_sym(&ldso, "__dls3", 0); + if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp); + else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp); +} + +/* 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. */ + +_Noreturn void __dls3(size_t *sp) +{ + static struct dso app, vdso; + size_t aux[AUX_CNT], *auxv; + size_t i; + char *env_preload=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; + for (i=argc+1; argv[i]; i++); + libc.auxv = auxv = (void *)(argv+i+1); + decode_vec(auxv, aux, AUX_CNT); + __hwcap = aux[AT_HWCAP]; + 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]); + + /* 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. */ + libc.tls_size = sizeof builtin_tls; + libc.tls_align = tls_align; + if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) { + a_crash(); + } + + /* 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 { + 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_get_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); + } + runtime = 1; + Ehdr *ehdr = (void *)map_library(fd, &app); + if (!ehdr) { + dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]); + _exit(1); + } + runtime = 0; + 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 = &app.tls; + app.tls_id = tls_cnt = 1; +#ifdef TLS_ABOVE_TP + app.tls.offset = 0; + tls_offset = app.tls.size + + ( -((uintptr_t)app.tls.image + app.tls.size) + & (app.tls.align-1) ); +#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); + } + app.global = 1; + 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; + } + + /* Attach to vdso, if provided by the kernel */ + if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) { + 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.global = 1; + vdso.relocated = 1; + decode_dyn(&vdso); + vdso.prev = &ldso; + ldso.next = &vdso; + } + + /* Initial dso chain consists only of the app. */ + head = tail = &app; + + /* Donate unused parts of app and library mapping to malloc */ + reclaim_gaps(&app); + reclaim_gaps(&ldso); + + /* Load preload/needed libraries, add their symbols to the global + * namespace, and perform all remaining relocations. */ + if (env_preload) load_preload(env_preload); + load_deps(&app); + make_global(&app); + +#ifndef DYNAMIC_IS_RO + for (i=0; app.dynv[i]; i+=2) + if (app.dynv[i]==DT_DEBUG) + app.dynv[i+1] = (size_t)&debug; +#endif + + /* The main program must be relocated LAST since it may contin + * copy relocations which depend on libraries' relocations. */ + reloc_all(app.next); + reloc_all(&app); + + update_tls_size(); + if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) { + void *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); + } + 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; + } + static_tls_cnt = tls_cnt; + + if (ldso_fail) _exit(127); + if (ldd_mode) _exit(0); + + /* 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 = 0; + _dl_debug_state(); + + errno = 0; + + CRTJMP((void *)aux[AT_ENTRY], argv-1); + for(;;); +} + +void *dlopen(const char *file, int mode) +{ + struct dso *volatile p, *orig_tail, *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; + + if (!file) return head; + + pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); + pthread_rwlock_wrlock(&lock); + __inhibit_ptc(); + + p = 0; + orig_tls_tail = tls_tail; + orig_tls_cnt = tls_cnt; + orig_tls_offset = tls_offset; + orig_tls_align = tls_align; + orig_tail = tail; + noload = mode & RTLD_NOLOAD; + + rtld_fail = &jb; + if (setjmp(*rtld_fail)) { + /* Clean up anything new that was (partially) loaded */ + if (p && p->deps) for (i=0; p->deps[i]; i++) + if (p->deps[i]->global < 0) + p->deps[i]->global = 0; + for (p=orig_tail->next; p; p=next) { + 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); + } + if (!orig_tls_tail) libc.tls_head = 0; + tls_tail = orig_tls_tail; + tls_cnt = orig_tls_cnt; + tls_offset = orig_tls_offset; + tls_align = orig_tls_align; + 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 */ + if (!p->deps) { + load_deps(p); + if (p->deps) for (i=0; p->deps[i]; i++) + if (!p->deps[i]->global) + p->deps[i]->global = -1; + if (!p->global) p->global = -1; + reloc_all(p); + if (p->deps) for (i=0; p->deps[i]; i++) + if (p->deps[i]->global < 0) + p->deps[i]->global = 0; + if (p->global < 0) p->global = 0; + } + + if (mode & RTLD_GLOBAL) { + if (p->deps) for (i=0; p->deps[i]; i++) + p->deps[i]->global = 1; + p->global = 1; + } + + update_tls_size(); + _dl_debug_state(); + orig_tail = tail; +end: + __release_ptc(); + if (p) gencnt++; + pthread_rwlock_unlock(&lock); + if (p) do_init_fini(orig_tail); + pthread_setcancelstate(cs, 0); + return p; +} + +__attribute__((__visibility__("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 { + if (a-(size_t)p->map < p->map_len) + return p; + } + } + return 0; +} + +void *__tls_get_addr(size_t *); + +static void *do_dlsym(struct dso *p, const char *s, void *ra) +{ + size_t i; + uint32_t h = 0, gh = 0, *ght; + Sym *sym; + if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) { + if (p == RTLD_DEFAULT) { + p = head; + } else if (p == RTLD_NEXT) { + p = addr2dso((size_t)ra); + if (!p) p=head; + p = p->next; + } + struct symdef def = find_sym(p, s, 0); + if (!def.sym) goto failed; + if ((def.sym->st_info&0xf) == STT_TLS) + return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value}); + if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC) + return def.dso->funcdescs + (def.sym - def.dso->syms); + return laddr(def.dso, def.sym->st_value); + } + if (__dl_invalid_handle(p)) + return 0; + if ((ght = p->ghashtab)) { + gh = gnu_hash(s); + sym = gnu_lookup(gh, ght, p, s); + } else { + h = sysv_hash(s); + sym = sysv_lookup(s, h, p); + } + if (sym && (sym->st_info&0xf) == STT_TLS) + return __tls_get_addr((size_t []){p->tls_id, sym->st_value}); + if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC) + return p->funcdescs + (sym - p->syms); + if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) + return laddr(p, sym->st_value); + if (p->deps) for (i=0; p->deps[i]; i++) { + if ((ght = p->deps[i]->ghashtab)) { + if (!gh) gh = gnu_hash(s); + sym = gnu_lookup(gh, ght, p->deps[i], s); + } else { + if (!h) h = sysv_hash(s); + sym = sysv_lookup(s, h, p->deps[i]); + } + if (sym && (sym->st_info&0xf) == STT_TLS) + return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value}); + if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC) + return p->deps[i]->funcdescs + (sym - p->deps[i]->syms); + if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) + return laddr(p->deps[i], sym->st_value); + } +failed: + error("Symbol not found: %s", s); + return 0; +} + +int dladdr(const void *addr, Dl_info *info) +{ + struct dso *p; + Sym *sym, *bestsym; + uint32_t nsym; + char *strings; + void *best = 0; + + pthread_rwlock_rdlock(&lock); + p = addr2dso((size_t)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 = ((size_t)addr-(size_t)p->funcdescs) + / sizeof(*p->funcdescs); + if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) { + best = p->funcdescs + idx; + bestsym = sym + idx; + } + } + + if (!best) for (; nsym; nsym--, sym++) { + if (sym->st_value + && (1<<(sym->st_info&0xf) & OK_TYPES) + && (1<<(sym->st_info>>4) & OK_BINDS)) { + void *symaddr = laddr(p, sym->st_value); + if (symaddr > addr || symaddr < best) + continue; + best = symaddr; + bestsym = sym; + if (addr == symaddr) + break; + } + } + + if (!best) return 0; + + if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC) + best = p->funcdescs + (bestsym - p->syms); + + info->dli_fname = p->name; + info->dli_fbase = p->base; + info->dli_sname = strings + bestsym->st_name; + info->dli_saddr = best; + + return 1; +} + +__attribute__((__visibility__("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; +} + +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.image; + + ret = (callback)(&info, sizeof (info), data); + + if (ret != 0) break; + + pthread_rwlock_rdlock(&lock); + current = current->next; + pthread_rwlock_unlock(&lock); + } + return ret; +} + +__attribute__((__visibility__("hidden"))) +void __dl_vseterr(const char *, va_list); + +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); +} |