| #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 *, ...); |
| |
| #ifdef SHARED |
| |
| #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 { |
| unsigned char *base; |
| 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; |
| void *tls_image; |
| size_t tls_len, tls_size, tls_align, tls_id, tls_offset; |
| 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; |
| char buf[]; |
| }; |
| |
| struct symdef { |
| Sym *sym; |
| struct dso *dso; |
| }; |
| |
| int __init_tp(void *); |
| void __init_libc(char **, char *); |
| |
| 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 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 }; |
| |
| struct debug *_dl_debug_addr = &debug; |
| |
| 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) |
| |
| 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*33 + *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(const char *s, uint32_t h1, struct dso *dso) |
| { |
| Sym *syms = dso->syms; |
| char *strings = dso->strings; |
| uint32_t *hashtab = dso->ghashtab; |
| uint32_t nbuckets = hashtab[0]; |
| uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4); |
| uint32_t h2; |
| uint32_t *hashval; |
| uint32_t i = buckets[h1 % nbuckets]; |
| |
| if (!i) return 0; |
| |
| hashval = buckets + nbuckets + (i - hashtab[1]); |
| |
| for (h1 |= 1; ; i++) { |
| h2 = *hashval++; |
| if ((!dso->versym || dso->versym[i] >= 0) |
| && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name)) |
| return syms+i; |
| if (h2 & 1) break; |
| } |
| |
| return 0; |
| } |
| |
| #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 = 0; |
| struct symdef def = {0}; |
| for (; dso; dso=dso->next) { |
| Sym *sym; |
| if (!dso->global) continue; |
| if (dso->ghashtab) { |
| if (!gh) gh = gnu_hash(s); |
| sym = gnu_lookup(s, gh, dso); |
| } 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])) continue; |
| type = R_TYPE(rel[1]); |
| if (type == REL_NONE) continue; |
| sym_index = R_SYM(rel[1]); |
| reloc_addr = (void *)(base + rel[0]); |
| if (sym_index) { |
| sym = syms + sym_index; |
| name = strings + sym->st_name; |
| ctx = type==REL_COPY ? head->next : head; |
| def = 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)def.dso->base+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_DTPMOD: |
| *reloc_addr = def.dso->tls_id; |
| break; |
| case REL_DTPOFF: |
| *reloc_addr = tls_val + addend; |
| 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 = (size_t *)(dso->base + start); |
| z = (size_t *)(dso->base + 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; |
| |
| 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 *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; |
| 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; |
| 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; |
| 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 = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start); |
| if (map==MAP_FAILED) goto error; |
| /* 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) 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(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((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) < 0) |
| goto error; |
| break; |
| } |
| dso->map = map; |
| dso->map_len = map_len; |
| dso->base = base; |
| dso->dynv = (void *)(base+dyn); |
| if (dso->tls_size) dso->tls_image = (void *)(base+tls_image); |
| if (!runtime) reclaim_gaps(dso); |
| free(allocated_buf); |
| return map; |
| noexec: |
| errno = ENOEXEC; |
| error: |
| if (map!=MAP_FAILED) munmap(map, map_len); |
| 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 = (void *)(p->base + dyn[DT_SYMTAB]); |
| p->strings = (void *)(p->base + dyn[DT_STRTAB]); |
| if (dyn[0]&(1<<DT_HASH)) |
| p->hashtab = (void *)(p->base + dyn[DT_HASH]); |
| if (dyn[0]&(1<<DT_RPATH)) |
| p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]); |
| if (dyn[0]&(1<<DT_RUNPATH)) |
| p->rpath_orig = (void *)(p->strings + dyn[DT_RUNPATH]); |
| if (search_vec(p->dynv, dyn, DT_GNU_HASH)) |
| p->ghashtab = (void *)(p->base + *dyn); |
| if (search_vec(p->dynv, dyn, DT_VERSYM)) |
| p->versym = (void *)(p->base + *dyn); |
| } |
| |
| 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) { |
| munmap(map, temp_dso.map_len); |
| 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)); |
| } |
| |
| tail->next = p; |
| p->prev = tail; |
| tail = 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, (void *)(p->base+dyn[DT_PLTGOT])); |
| do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ], |
| 2+(dyn[DT_PLTREL]==DT_RELA)); |
| do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2); |
| do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3); |
| |
| if (head != &ldso && p->relro_start != p->relro_end && |
| mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) { |
| 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 = (void *)(p->base + 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; |
| } |
| |
| static void do_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 *)(p->base + dyn[DT_FINI_ARRAY])+n; |
| while (n--) ((void (*)(void))*--fn)(); |
| } |
| #ifndef NO_LEGACY_INITFINI |
| if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI]) |
| ((void (*)(void))(p->base + 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]) |
| ((void (*)(void))(p->base + dyn[DT_INIT]))(); |
| #endif |
| if (dyn[0] & (1<<DT_INIT_ARRAY)) { |
| size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t); |
| size_t *fn = (void *)(p->base + 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); |
| } |
| |
| static void dl_debug_state(void) |
| { |
| } |
| |
| weak_alias(dl_debug_state, _dl_debug_state); |
| |
| void __reset_tls() |
| { |
| pthread_t self = __pthread_self(); |
| struct dso *p; |
| for (p=head; p; p=p->next) { |
| if (!p->tls_id || !self->dtv[p->tls_id]) continue; |
| memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len); |
| memset((char *)self->dtv[p->tls_id]+p->tls_len, 0, |
| p->tls_size - p->tls_len); |
| if (p->tls_id == (size_t)self->dtv[0]) break; |
| } |
| } |
| |
| void *__copy_tls(unsigned char *mem) |
| { |
| pthread_t td; |
| struct dso *p; |
| void **dtv; |
| |
| #ifdef TLS_ABOVE_TP |
| dtv = (void **)(mem + libc.tls_size) - (tls_cnt + 1); |
| |
| mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1); |
| td = (pthread_t)mem; |
| mem += sizeof(struct pthread); |
| |
| for (p=head; p; p=p->next) { |
| if (!p->tls_id) continue; |
| dtv[p->tls_id] = mem + p->tls_offset; |
| memcpy(dtv[p->tls_id], p->tls_image, p->tls_len); |
| } |
| #else |
| dtv = (void **)mem; |
| |
| mem += libc.tls_size - sizeof(struct pthread); |
| mem -= (uintptr_t)mem & (tls_align-1); |
| td = (pthread_t)mem; |
| |
| for (p=head; p; p=p->next) { |
| if (!p->tls_id) continue; |
| dtv[p->tls_id] = mem - p->tls_offset; |
| memcpy(dtv[p->tls_id], p->tls_image, p->tls_len); |
| } |
| #endif |
| dtv[0] = (void *)tls_cnt; |
| td->dtv = td->dtv_copy = dtv; |
| return td; |
| } |
| |
| __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]; |
| } |
| |
| /* 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)*sizeof(void *)*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]; |
| } |
| |
| static void update_tls_size() |
| { |
| 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. */ |
| |
| void __dls2(unsigned char *base, size_t *sp) |
| { |
| Ehdr *ehdr = (void *)base; |
| ldso.base = base; |
| ldso.name = ldso.shortname = "libc.so"; |
| ldso.global = 1; |
| ldso.phnum = ehdr->e_phnum; |
| ldso.phdr = (void *)(base + ehdr->e_phoff); |
| ldso.phentsize = ehdr->e_phentsize; |
| kernel_mapped_dso(&ldso); |
| decode_dyn(&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 = (void *)(base+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])) 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); |
| ((stage3_func)(ldso.base+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; |
| |
| /* 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; |
| if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) { |
| a_crash(); |
| } |
| |
| /* Find aux vector just past environ[] */ |
| for (i=argc+1; argv[i]; i++) |
| if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16)) |
| env_path = argv[i]+16; |
| else if (!memcmp(argv[i], "LD_PRELOAD=", 11)) |
| env_preload = argv[i]+11; |
| auxv = (void *)(argv+i+1); |
| |
| decode_vec(auxv, aux, AUX_CNT); |
| |
| /* Only trust user/env if kernel says we're not suid/sgid */ |
| if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID] |
| || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) { |
| env_path = 0; |
| env_preload = 0; |
| libc.secure = 1; |
| } |
| libc.page_size = aux[AT_PAGESZ]; |
| libc.auxv = auxv; |
| |
| /* 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 (app.tls_size) app.tls_image = (char *)app.base + tls_image; |
| if (interp_off) ldso.name = (char *)app.base + 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\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)app.base + 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 = (void *)(app.base |
| + app.phdr[i].p_vaddr); |
| } |
| dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base); |
| } |
| } |
| if (app.tls_size) { |
| 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); |
| |
| /* 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(); |
| |
| __init_libc(envp, argv[0]); |
| atexit(do_fini); |
| errno = 0; |
| do_init_fini(tail); |
| |
| CRTJMP((void *)aux[AT_ENTRY], argv-1); |
| for(;;); |
| } |
| |
| void *dlopen(const char *file, int mode) |
| { |
| struct dso *volatile p, *orig_tail, *next; |
| 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_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; |
| munmap(p->map, p->map_len); |
| while (p->td_index) { |
| void *tmp = p->td_index->next; |
| free(p->td_index); |
| p->td_index = tmp; |
| } |
| if (p->rpath != p->rpath_orig) |
| free(p->rpath); |
| free(p->deps); |
| free(p); |
| } |
| 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; |
| } |
| |
| static int invalid_dso_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; |
| } |
| |
| 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; |
| Sym *sym; |
| if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) { |
| if (p == RTLD_DEFAULT) { |
| p = head; |
| } else if (p == RTLD_NEXT) { |
| for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next); |
| 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}); |
| return def.dso->base + def.sym->st_value; |
| } |
| if (invalid_dso_handle(p)) |
| return 0; |
| if (p->ghashtab) { |
| gh = gnu_hash(s); |
| sym = gnu_lookup(s, gh, p); |
| } 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 (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) |
| return p->base + sym->st_value; |
| if (p->deps) for (i=0; p->deps[i]; i++) { |
| if (p->deps[i]->ghashtab) { |
| if (!gh) gh = gnu_hash(s); |
| sym = gnu_lookup(s, gh, p->deps[i]); |
| } 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 (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) |
| return p->deps[i]->base + 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; |
| uint32_t nsym; |
| char *strings; |
| size_t i; |
| void *best = 0; |
| char *bestname; |
| |
| pthread_rwlock_rdlock(&lock); |
| for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next); |
| pthread_rwlock_unlock(&lock); |
| |
| if (!p) return 0; |
| |
| sym = p->syms; |
| strings = p->strings; |
| if (p->hashtab) { |
| nsym = p->hashtab[1]; |
| } else { |
| uint32_t *buckets; |
| uint32_t *hashval; |
| buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4); |
| sym += p->ghashtab[1]; |
| for (i = nsym = 0; i < p->ghashtab[0]; i++) { |
| if (buckets[i] > nsym) |
| nsym = buckets[i]; |
| } |
| if (nsym) { |
| nsym -= p->ghashtab[1]; |
| hashval = buckets + p->ghashtab[0] + nsym; |
| do nsym++; |
| while (!(*hashval++ & 1)); |
| } |
| } |
| |
| for (; nsym; nsym--, sym++) { |
| if (sym->st_value |
| && (1<<(sym->st_info&0xf) & OK_TYPES) |
| && (1<<(sym->st_info>>4) & OK_BINDS)) { |
| void *symaddr = p->base + sym->st_value; |
| if (symaddr > addr || symaddr < best) |
| continue; |
| best = symaddr; |
| bestname = strings + sym->st_name; |
| if (addr == symaddr) |
| break; |
| } |
| } |
| |
| if (!best) return 0; |
| |
| info->dli_fname = p->name; |
| info->dli_fbase = p->base; |
| info->dli_sname = bestname; |
| 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; |
| } |
| #else |
| static int invalid_dso_handle(void *h) |
| { |
| error("Invalid library handle %p", (void *)h); |
| return 1; |
| } |
| void *dlopen(const char *file, int mode) |
| { |
| error("Dynamic loading not supported"); |
| return 0; |
| } |
| void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra) |
| { |
| error("Symbol not found: %s", s); |
| return 0; |
| } |
| int __dladdr (const void *addr, Dl_info *info) |
| { |
| return 0; |
| } |
| #endif |
| |
| int __dlinfo(void *dso, int req, void *res) |
| { |
| if (invalid_dso_handle(dso)) return -1; |
| if (req != RTLD_DI_LINKMAP) { |
| error("Unsupported request %d", req); |
| return -1; |
| } |
| *(struct link_map **)res = dso; |
| return 0; |
| } |
| |
| char *dlerror() |
| { |
| pthread_t self = __pthread_self(); |
| if (!self->dlerror_flag) return 0; |
| self->dlerror_flag = 0; |
| char *s = self->dlerror_buf; |
| if (s == (void *)-1) |
| return "Dynamic linker failed to allocate memory for error message"; |
| else |
| return s; |
| } |
| |
| int dlclose(void *p) |
| { |
| return invalid_dso_handle(p); |
| } |
| |
| void __dl_thread_cleanup(void) |
| { |
| pthread_t self = __pthread_self(); |
| if (self->dlerror_buf != (void *)-1) |
| free(self->dlerror_buf); |
| } |
| |
| static void error(const char *fmt, ...) |
| { |
| va_list ap; |
| va_start(ap, fmt); |
| #ifdef SHARED |
| if (!runtime) { |
| vdprintf(2, fmt, ap); |
| dprintf(2, "\n"); |
| ldso_fail = 1; |
| va_end(ap); |
| return; |
| } |
| #endif |
| pthread_t self = __pthread_self(); |
| if (self->dlerror_buf != (void *)-1) |
| free(self->dlerror_buf); |
| size_t len = vsnprintf(0, 0, fmt, ap); |
| va_end(ap); |
| char *buf = malloc(len+1); |
| if (buf) { |
| va_start(ap, fmt); |
| vsnprintf(buf, len+1, fmt, ap); |
| va_end(ap); |
| } else { |
| buf = (void *)-1; |
| } |
| self->dlerror_buf = buf; |
| self->dlerror_flag = 1; |
| } |