| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <stdint.h> |
| #include <elf.h> |
| #include <sys/mman.h> |
| #include <limits.h> |
| #include <stdint.h> |
| #include <fcntl.h> |
| #include <sys/stat.h> |
| #include <errno.h> |
| #include <limits.h> |
| #include <elf.h> |
| #include <setjmp.h> |
| #include <pthread.h> |
| #include <ctype.h> |
| #include <dlfcn.h> |
| |
| static int errflag; |
| static char errbuf[128]; |
| |
| #ifdef SHARED |
| |
| #include "reloc.h" |
| |
| #if ULONG_MAX == 0xffffffff |
| typedef Elf32_Ehdr Ehdr; |
| typedef Elf32_Phdr Phdr; |
| typedef Elf32_Sym Sym; |
| #define R_TYPE(x) ((x)&255) |
| #define R_SYM(x) ((x)>>8) |
| #else |
| typedef Elf64_Ehdr Ehdr; |
| typedef Elf64_Phdr Phdr; |
| typedef Elf64_Sym Sym; |
| #define R_TYPE(x) ((x)&0xffffffff) |
| #define R_SYM(x) ((x)>>32) |
| #endif |
| |
| struct debug { |
| int ver; |
| void *head; |
| void (*bp)(void); |
| int state; |
| void *base; |
| }; |
| |
| struct dso { |
| unsigned char *base; |
| char *name; |
| size_t *dynv; |
| struct dso *next, *prev; |
| |
| int refcnt; |
| Sym *syms; |
| uint32_t *hashtab; |
| char *strings; |
| unsigned char *map; |
| size_t map_len; |
| dev_t dev; |
| ino_t ino; |
| signed char global; |
| char relocated; |
| char constructed; |
| struct dso **deps; |
| char *shortname; |
| char buf[]; |
| }; |
| |
| void __init_ssp(size_t *); |
| |
| static struct dso *head, *tail, *libc; |
| static char *env_path, *sys_path, *r_path; |
| static int rtld_used; |
| static int ssp_used; |
| static int runtime; |
| static int ldd_mode; |
| static jmp_buf rtld_fail; |
| static pthread_rwlock_t lock; |
| static struct debug debug; |
| |
| struct debug *_dl_debug_addr = &debug; |
| |
| #define AUX_CNT 24 |
| #define DYN_CNT 34 |
| |
| static void decode_vec(size_t *v, size_t *a, size_t cnt) |
| { |
| memset(a, 0, cnt*sizeof(size_t)); |
| for (; v[0]; v+=2) if (v[0]<cnt) { |
| a[0] |= 1ULL<<v[0]; |
| a[v[0]] = v[1]; |
| } |
| } |
| |
| static uint32_t 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 Sym *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 (!strcmp(s, strings+syms[i].st_name)) |
| return syms+i; |
| } |
| return 0; |
| } |
| |
| #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON) |
| #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK) |
| |
| static void *find_sym(struct dso *dso, const char *s, int need_def) |
| { |
| uint32_t h = hash(s); |
| void *def = 0; |
| if (h==0x6b366be && !strcmp(s, "dlopen")) rtld_used = 1; |
| if (h==0x6b3afd && !strcmp(s, "dlsym")) rtld_used = 1; |
| if (h==0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1; |
| for (; dso; dso=dso->next) { |
| Sym *sym; |
| if (!dso->global) continue; |
| sym = lookup(s, h, dso); |
| if (sym && (!need_def || sym->st_shndx) && sym->st_value |
| && (1<<(sym->st_info&0xf) & OK_TYPES) |
| && (1<<(sym->st_info>>4) & OK_BINDS)) { |
| if (def && sym->st_info>>4 == STB_WEAK) continue; |
| def = dso->base + sym->st_value; |
| if (sym->st_info>>4 == STB_GLOBAL) break; |
| } |
| } |
| return def; |
| } |
| |
| static void do_relocs(unsigned char *base, size_t *rel, size_t rel_size, size_t stride, Sym *syms, char *strings) |
| { |
| Sym *sym; |
| const char *name; |
| size_t sym_val, sym_size; |
| size_t *reloc_addr; |
| void *ctx; |
| int type; |
| int sym_index; |
| |
| for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) { |
| reloc_addr = (void *)(base + rel[0]); |
| type = R_TYPE(rel[1]); |
| sym_index = R_SYM(rel[1]); |
| if (sym_index) { |
| sym = syms + sym_index; |
| name = strings + sym->st_name; |
| ctx = IS_COPY(type) ? head->next : head; |
| sym_val = (size_t)find_sym(ctx, name, IS_PLT(type)); |
| if (!sym_val && sym->st_info>>4 != STB_WEAK) { |
| snprintf(errbuf, sizeof errbuf, |
| "Error relocating %s: %s: symbol not found", |
| "???", name); |
| if (runtime) longjmp(rtld_fail, 1); |
| dprintf(2, "%s\n", errbuf); |
| _exit(127); |
| } |
| sym_size = sym->st_size; |
| } |
| do_single_reloc(reloc_addr, type, sym_val, sym_size, base, rel[2]); |
| } |
| } |
| |
| /* 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(unsigned char *base, size_t start, size_t end) |
| { |
| size_t *a, *z; |
| 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 *)(base + start); |
| z = (size_t *)(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(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt) |
| { |
| for (; phcnt--; ph=(void *)((char *)ph+phent)) { |
| if (ph->p_type!=PT_LOAD) continue; |
| if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue; |
| reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr); |
| reclaim(base, ph->p_vaddr+ph->p_memsz, |
| ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE); |
| } |
| } |
| |
| static void *map_library(int fd, size_t *lenp, unsigned char **basep, size_t *dynp) |
| { |
| Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)]; |
| 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; |
| unsigned prot; |
| unsigned char *map, *base; |
| size_t dyn; |
| size_t i; |
| |
| ssize_t l = read(fd, buf, sizeof buf); |
| if (l<sizeof *eh) return 0; |
| eh = buf; |
| phsize = eh->e_phentsize * eh->e_phnum; |
| if (phsize + sizeof *eh > l) return 0; |
| if (eh->e_phoff + phsize > l) { |
| l = pread(fd, buf+1, phsize, eh->e_phoff); |
| if (l != phsize) return 0; |
| eh->e_phoff = sizeof *eh; |
| } |
| ph = (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; |
| 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) return 0; |
| 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) return 0; |
| base = map - addr_min; |
| ph = (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_LOAD) continue; |
| /* 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; |
| } |
| if (!runtime) reclaim_gaps(base, (void *)((char *)buf + eh->e_phoff), |
| eh->e_phentsize, eh->e_phnum); |
| *lenp = map_len; |
| *basep = base; |
| *dynp = dyn; |
| return map; |
| error: |
| munmap(map, map_len); |
| return 0; |
| } |
| |
| static int path_open(const char *name, const char *search, char *buf, size_t buf_size) |
| { |
| const char *s=search, *z; |
| int l, fd; |
| for (;;) { |
| while (*s==':') s++; |
| if (!*s) return -1; |
| z = strchr(s, ':'); |
| l = z ? z-s : strlen(s); |
| snprintf(buf, buf_size, "%.*s/%s", l, s, name); |
| if ((fd = open(buf, O_RDONLY))>=0) return fd; |
| s += l; |
| } |
| } |
| |
| static void decode_dyn(struct dso *p) |
| { |
| size_t dyn[DYN_CNT] = {0}; |
| decode_vec(p->dynv, dyn, DYN_CNT); |
| p->syms = (void *)(p->base + dyn[DT_SYMTAB]); |
| p->hashtab = (void *)(p->base + dyn[DT_HASH]); |
| p->strings = (void *)(p->base + dyn[DT_STRTAB]); |
| } |
| |
| static struct dso *load_library(const char *name) |
| { |
| char buf[2*NAME_MAX+2]; |
| const char *pathname; |
| unsigned char *base, *map; |
| size_t dyno, map_len; |
| struct dso *p; |
| int fd; |
| struct stat st; |
| |
| /* 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 && memcmp(name+3, rp, l-3); rp+=strlen(rp)+1); |
| if (*rp) { |
| if (!libc->prev) { |
| tail->next = libc; |
| libc->prev = tail; |
| tail = libc->next ? libc->next : libc; |
| } |
| return libc; |
| } |
| } |
| } |
| if (strchr(name, '/')) { |
| pathname = name; |
| fd = open(name, O_RDONLY); |
| } 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 (r_path) fd = path_open(name, r_path, buf, sizeof buf); |
| if (fd < 0 && env_path) fd = path_open(name, env_path, buf, sizeof buf); |
| if (fd < 0) { |
| if (!sys_path) { |
| FILE *f = fopen(ETC_LDSO_PATH, "r"); |
| if (f) { |
| if (getline(&sys_path, (size_t[1]){0}, f) > 0) |
| sys_path[strlen(sys_path)-1]=0; |
| fclose(f); |
| } |
| } |
| if (sys_path) fd = path_open(name, sys_path, buf, sizeof buf); |
| else fd = path_open(name, "/lib:/usr/local/lib:/usr/lib", 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) p->shortname = strrchr(p->name, '/')+1; |
| close(fd); |
| p->refcnt++; |
| return p; |
| } |
| } |
| map = map_library(fd, &map_len, &base, &dyno); |
| close(fd); |
| if (!map) return 0; |
| p = calloc(1, sizeof *p + strlen(pathname) + 1); |
| if (!p) { |
| munmap(map, map_len); |
| return 0; |
| } |
| |
| p->map = map; |
| p->map_len = map_len; |
| p->base = base; |
| p->dynv = (void *)(base + dyno); |
| decode_dyn(p); |
| |
| p->dev = st.st_dev; |
| p->ino = st.st_ino; |
| p->refcnt = 1; |
| 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; |
| |
| tail->next = p; |
| p->prev = tail; |
| tail = p; |
| |
| if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, 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_RPATH) continue; |
| r_path = (void *)(p->strings + p->dynv[i+1]); |
| } |
| for (i=0; p->dynv[i]; i+=2) { |
| if (p->dynv[i] != DT_NEEDED) continue; |
| dep = load_library(p->strings + p->dynv[i+1]); |
| if (!dep) { |
| snprintf(errbuf, sizeof errbuf, |
| "Error loading shared library %s: %m (needed by %s)", |
| p->strings + p->dynv[i+1], p->name); |
| if (runtime) longjmp(rtld_fail, 1); |
| dprintf(2, "%s\n", errbuf); |
| _exit(127); |
| } |
| if (runtime) { |
| tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2)); |
| if (!tmp) longjmp(rtld_fail, 1); |
| tmp[ndeps++] = dep; |
| tmp[ndeps] = 0; |
| *deps = tmp; |
| } |
| } |
| r_path = 0; |
| } |
| } |
| |
| static void load_preload(char *s) |
| { |
| int tmp; |
| char *z; |
| for (z=s; *z; s=z) { |
| for ( ; *s && isspace(*s); s++); |
| for (z=s; *z && !isspace(*z); z++); |
| tmp = *z; |
| *z = 0; |
| load_library(s); |
| *z = tmp; |
| } |
| } |
| |
| static void make_global(struct dso *p) |
| { |
| for (; p; p=p->next) p->global = 1; |
| } |
| |
| static void reloc_all(struct dso *p) |
| { |
| size_t dyn[DYN_CNT] = {0}; |
| for (; p; p=p->next) { |
| if (p->relocated) continue; |
| decode_vec(p->dynv, dyn, DYN_CNT); |
| do_relocs(p->base, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ], |
| 2+(dyn[DT_PLTREL]==DT_RELA), p->syms, p->strings); |
| do_relocs(p->base, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], |
| 2, p->syms, p->strings); |
| do_relocs(p->base, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], |
| 3, p->syms, p->strings); |
| p->relocated = 1; |
| } |
| } |
| |
| static void free_all(struct dso *p) |
| { |
| struct dso *n; |
| while (p) { |
| n = p->next; |
| if (p->map) free(p); |
| p = n; |
| } |
| } |
| |
| static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride) |
| { |
| for (; cnt--; ph = (void *)((char *)ph + stride)) |
| if (ph->p_type == PT_DYNAMIC) |
| return ph->p_vaddr; |
| return 0; |
| } |
| |
| static void do_init_fini(struct dso *p) |
| { |
| size_t dyn[DYN_CNT] = {0}; |
| for (; p; p=p->prev) { |
| if (p->constructed) return; |
| decode_vec(p->dynv, dyn, DYN_CNT); |
| if (dyn[0] & (1<<DT_FINI)) |
| atexit((void (*)(void))(p->base + dyn[DT_FINI])); |
| if (dyn[0] & (1<<DT_INIT)) |
| ((void (*)(void))(p->base + dyn[DT_INIT]))(); |
| p->constructed = 1; |
| } |
| } |
| |
| void _dl_debug_state(void) |
| { |
| } |
| |
| void *__dynlink(int argc, char **argv) |
| { |
| size_t *auxv, aux[AUX_CNT] = {0}; |
| size_t i; |
| Phdr *phdr; |
| Ehdr *ehdr; |
| static struct dso builtin_dsos[3]; |
| struct dso *const app = builtin_dsos+0; |
| struct dso *const lib = builtin_dsos+1; |
| struct dso *const vdso = builtin_dsos+2; |
| char *env_preload=0; |
| |
| /* 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; |
| } |
| |
| /* If the dynamic linker was invoked as a program itself, AT_BASE |
| * will not be set. In that case, we assume the base address is |
| * the start of the page containing the PHDRs; I don't know any |
| * better approach... */ |
| if (!aux[AT_BASE]) { |
| aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE; |
| aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0; |
| } |
| |
| /* The dynamic linker load address is passed by the kernel |
| * in the AUX vector, so this is easy. */ |
| lib->base = (void *)aux[AT_BASE]; |
| lib->name = lib->shortname = "libc.so"; |
| lib->global = 1; |
| ehdr = (void *)lib->base; |
| lib->dynv = (void *)(lib->base + find_dyn( |
| (void *)(aux[AT_BASE]+ehdr->e_phoff), |
| ehdr->e_phnum, ehdr->e_phentsize)); |
| decode_dyn(lib); |
| |
| if (aux[AT_PHDR]) { |
| size_t interp_off = 0; |
| /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */ |
| phdr = (void *)aux[AT_PHDR]; |
| 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; |
| } |
| if (interp_off) lib->name = (char *)app->base + interp_off; |
| app->name = argv[0]; |
| app->dynv = (void *)(app->base + find_dyn( |
| (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT])); |
| } else { |
| int fd; |
| char *ldname = argv[0]; |
| size_t dyno, l = strlen(ldname); |
| if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1; |
| *argv++ = (void *)-1; |
| if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1; |
| if (!argv[0]) { |
| dprintf(2, "musl libc/dynamic program loader\n"); |
| dprintf(2, "usage: %s pathname%s\n", 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 = (void *)map_library(fd, &app->map_len, &app->base, &dyno); |
| if (!ehdr) { |
| dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]); |
| _exit(1); |
| } |
| runtime = 0; |
| close(fd); |
| lib->name = ldname; |
| app->name = argv[0]; |
| app->dynv = (void *)(app->base + dyno); |
| aux[AT_ENTRY] = ehdr->e_entry; |
| } |
| app->global = 1; |
| app->constructed = 1; |
| decode_dyn(app); |
| |
| /* Attach to vdso, if provided by the kernel */ |
| for (i=0; auxv[i]; i+=2) { |
| size_t vdso_base = auxv[i+1]; |
| if (auxv[i] != AT_SYSINFO_EHDR) continue; |
| ehdr = (void *)vdso_base; |
| phdr = (void *)(vdso_base + ehdr->e_phoff); |
| 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; |
| decode_dyn(vdso); |
| vdso->prev = lib; |
| lib->next = vdso; |
| break; |
| } |
| |
| /* Initial dso chain consists only of the app. We temporarily |
| * append the dynamic linker/libc so we can relocate it, then |
| * restore the initial chain in preparation for loading third |
| * party libraries (preload/needed). */ |
| head = tail = app; |
| libc = lib; |
| app->next = lib; |
| reloc_all(lib); |
| app->next = 0; |
| |
| /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */ |
| |
| /* Donate unused parts of app and library mapping to malloc */ |
| reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]); |
| ehdr = (void *)lib->base; |
| reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff), |
| ehdr->e_phentsize, ehdr->e_phnum); |
| |
| /* Load preload/needed libraries, add their symbols to the global |
| * namespace, and perform all remaining relocations. The main |
| * program must be relocated LAST since it may contain copy |
| * relocations which depend on libraries' relocations. */ |
| if (env_preload) load_preload(env_preload); |
| load_deps(app); |
| make_global(app); |
| reloc_all(app->next); |
| reloc_all(app); |
| |
| 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. If the dynamic loader (dlopen) will not be used, free |
| * all memory used by the dynamic linker. */ |
| runtime = 1; |
| |
| for (i=0; app->dynv[i]; i+=2) |
| if (app->dynv[i]==DT_DEBUG) |
| app->dynv[i+1] = (size_t)&debug; |
| debug.ver = 1; |
| debug.bp = _dl_debug_state; |
| debug.head = head; |
| debug.base = lib->base; |
| debug.state = 0; |
| _dl_debug_state(); |
| |
| if (ssp_used) __init_ssp(auxv); |
| |
| do_init_fini(tail); |
| |
| if (!rtld_used) { |
| free_all(head); |
| free(sys_path); |
| reclaim((void *)builtin_dsos, 0, sizeof builtin_dsos); |
| } |
| |
| errno = 0; |
| return (void *)aux[AT_ENTRY]; |
| } |
| |
| void *dlopen(const char *file, int mode) |
| { |
| struct dso *volatile p, *orig_tail = tail, *next; |
| size_t i; |
| int cs; |
| |
| if (!file) return head; |
| |
| pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); |
| pthread_rwlock_wrlock(&lock); |
| |
| if (setjmp(rtld_fail)) { |
| /* Clean up anything new that was (partially) loaded */ |
| if (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); |
| free(p->deps); |
| free(p); |
| } |
| tail = orig_tail; |
| tail->next = 0; |
| p = 0; |
| errflag = 1; |
| goto end; |
| } else p = load_library(file); |
| |
| if (!p) { |
| snprintf(errbuf, sizeof errbuf, |
| "Error loading shared library %s: %m", file); |
| errflag = 1; |
| 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; |
| } |
| |
| _dl_debug_state(); |
| |
| do_init_fini(tail); |
| end: |
| pthread_rwlock_unlock(&lock); |
| pthread_setcancelstate(cs, 0); |
| return p; |
| } |
| |
| static void *do_dlsym(struct dso *p, const char *s, void *ra) |
| { |
| size_t i; |
| uint32_t h; |
| Sym *sym; |
| if (p == RTLD_NEXT) { |
| for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next); |
| if (!p) p=head; |
| void *res = find_sym(p->next, s, 0); |
| if (!res) goto failed; |
| return res; |
| } |
| if (p == head || p == RTLD_DEFAULT) { |
| void *res = find_sym(head, s, 0); |
| if (!res) goto failed; |
| return res; |
| } |
| h = hash(s); |
| sym = lookup(s, h, p); |
| 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++) { |
| sym = lookup(s, h, p); |
| if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) |
| return p->deps[i]->base + sym->st_value; |
| } |
| failed: |
| errflag = 1; |
| snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s); |
| return 0; |
| } |
| |
| void *__dlsym(void *p, const char *s, void *ra) |
| { |
| void *res; |
| pthread_rwlock_rdlock(&lock); |
| res = do_dlsym(p, s, ra); |
| pthread_rwlock_unlock(&lock); |
| return res; |
| } |
| #else |
| void *dlopen(const char *file, int mode) |
| { |
| return 0; |
| } |
| void *__dlsym(void *p, const char *s, void *ra) |
| { |
| return 0; |
| } |
| #endif |
| |
| char *dlerror() |
| { |
| if (!errflag) return 0; |
| errflag = 0; |
| return errbuf; |
| } |
| |
| int dlclose(void *p) |
| { |
| return 0; |
| } |