#define _GNU_SOURCE
#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 <link.h>
#include <setjmp.h>
#include <pthread.h>
#include <ctype.h>
#include <dlfcn.h>
#include "pthread_impl.h"
#include "libc.h"
static int errflag;
static char errbuf[128];
#ifdef SHARED
#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
#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 dso {
unsigned char *base;
char *name;
size_t *dynv;
struct dso *next, *prev;
Phdr *phdr;
int phnum;
int refcnt;
Sym *syms;
uint32_t *hashtab;
uint32_t *ghashtab;
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;
void *tls_image;
size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
void **new_dtv;
unsigned char *new_tls;
int new_dtv_idx, new_tls_idx;
struct dso *fini_next;
char *shortname;
char buf[];
};
struct symdef {
Sym *sym;
struct dso *dso;
};
#include "reloc.h"
void __init_ssp(size_t *);
void *__install_initial_tls(void *);
void __init_libc(char **, char *);
static struct dso *head, *tail, *ldso, *fini_head;
static char *env_path, *sys_path, *r_path;
static unsigned long long gencnt;
static int ssp_used;
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 = 4*sizeof(size_t);
static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
struct debug *_dl_debug_addr = &debug;
#define AUX_CNT 38
#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 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 (!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 *sym;
char *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 n = buckets[h1 % nbuckets];
if (!n) return 0;
strings = dso->strings;
sym = dso->syms + n;
hashval = buckets + nbuckets + (n - hashtab[1]);
for (h1 |= 1; ; sym++) {
h2 = *hashval++;
if ((h1 == (h2|1)) && !strcmp(s, strings + sym->st_name))
return sym;
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)
static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
{
uint32_t h = 0, gh = 0;
struct symdef def = {0};
if (dso->ghashtab) {
gh = gnu_hash(s);
if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
} else {
h = sysv_hash(s);
if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
}
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)
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;
}
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;
for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
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;
def = find_sym(ctx, name, IS_PLT(type));
if (!def.sym && sym->st_info>>4 != STB_WEAK) {
snprintf(errbuf, sizeof errbuf,
"Error relocating %s: %s: symbol not found",
dso->name, name);
if (runtime) longjmp(*rtld_fail, 1);
dprintf(2, "%s\n", errbuf);
ldso_fail = 1;
continue;
}
} else {
sym = 0;
def.sym = 0;
def.dso = 0;
}
do_single_reloc(dso, base, (void *)(base + rel[0]), type,
stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
}
}
/* A huge hack: to make up for the wastefulness of shared libraries
* needing at least a page of dirty memory even if they have no global
* data, we reclaim the gaps at the beginning and end of writable maps
* and "donate" them to the heap 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, struct dso *dso)
{
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, *ph0;
unsigned prot;
unsigned char *map, *base;
size_t dyn;
size_t tls_image=0;
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;
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;
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;
}
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;
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;
}
/* 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, ph0, eh->e_phentsize, eh->e_phnum);
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);
return map;
error:
munmap(map, map_len);
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)
continue;
if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=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->strings = (void *)(p->base + dyn[DT_STRTAB]);
if (dyn[0]&(1<<DT_HASH))
p->hashtab = (void *)(p->base + dyn[DT_HASH]);
if (search_vec(p->dynv, dyn, DT_GNU_HASH))
p->ghashtab = (void *)(p->base + *dyn);
}
static struct dso *load_library(const char *name)
{
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;
/* 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 (!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 (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) {
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);
}
}
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->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) {
if (runtime && !__pthread_self_init()) {
munmap(map, p->map_len);
free(p);
return 0;
}
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_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);
ldso_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;
}
}
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);
#ifdef NEED_ARCH_RELOCS
do_arch_relocs(p, head);
#endif
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);
p->relocated = 1;
}
}
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 find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
{
size_t min_addr = -1, max_addr = 0;
for (; cnt--; ph = (void *)((char *)ph + stride)) {
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;
}
static void do_fini()
{
struct dso *p;
size_t dyn[DYN_CNT] = {0};
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))
((void (*)(void))(p->base + dyn[DT_FINI]))();
#endif
}
}
static void do_init_fini(struct dso *p)
{
size_t dyn[DYN_CNT] = {0};
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))
((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);
}
void _dl_debug_state(void)
{
}
void *__copy_tls(unsigned char *mem)
{
pthread_t td;
struct dso *p;
if (!tls_cnt) return mem;
void **dtv = (void *)mem;
dtv[0] = (void *)tls_cnt;
#ifdef TLS_ABOVE_TP
mem += sizeof(void *) * (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
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
td->dtv = dtv;
return td;
}
void *__tls_get_addr(size_t *v)
{
pthread_t self = __pthread_self();
if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
return (char *)self->dtv[v[0]]+v[1];
/* Block signals to make accessing new TLS async-signal-safe */
sigset_t set;
pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
pthread_sigmask(SIG_SETMASK, &set, 0);
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 = newdtv;
}
/* Get new TLS memory from new DSO */
unsigned char *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[v[0]] = mem;
memcpy(mem, p->tls_image, p->tls_len);
pthread_sigmask(SIG_SETMASK, &set, 0);
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);
}
void *__dynlink(int argc, char **argv)
{
size_t 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;
size_t vdso_base;
size_t *auxv;
char **envp = argv+argc+1;
/* 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->phnum = ehdr->e_phnum;
lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
ehdr->e_phnum, ehdr->e_phentsize));
decode_dyn(lib);
if (aux[AT_PHDR]) {
size_t interp_off = 0;
size_t tls_image = 0;
/* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
app->phdr = phdr = (void *)aux[AT_PHDR];
app->phnum = aux[AT_PHNUM];
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) 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]));
find_map_range((void *)aux[AT_PHDR],
aux[AT_PHNUM], aux[AT_PHENT], 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++ = (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);
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->phnum = ehdr->e_phnum;
app->phdr = (void *)(app->base + ehdr->e_phoff);
aux[AT_ENTRY] = ehdr->e_entry;
}
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 = (void *)vdso_base;
vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
vdso->phnum = ehdr->e_phnum;
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;
}
/* 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;
ldso = 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);
update_tls_size();
if (tls_cnt) {
void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
if (mem==MAP_FAILED ||
!__install_initial_tls(__copy_tls(mem))) {
dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
argv[0], libc.tls_size);
_exit(127);
}
}
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. If the dynamic loader (dlopen) will not be used, free
* all memory used by the dynamic linker. */
runtime = 1;
#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
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((void *)aux[AT_RANDOM]);
__init_libc(envp, argv[0]);
atexit(do_fini);
errno = 0;
do_init_fini(tail);
return (void *)aux[AT_ENTRY];
}
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);
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;
errflag = 1;
goto end;
} else p = load_library(file);
if (!p) {
snprintf(errbuf, sizeof errbuf, noload ?
"Library %s is not already loaded" :
"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;
}
update_tls_size();
if (ssp_used) __init_ssp(libc.auxv);
_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;
snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
errflag = 1;
return 1;
}
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 (p != RTLD_DEFAULT && p != RTLD_NEXT && 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:
errflag = 1;
snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
return 0;
}
int __dladdr(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 = 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;
}
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)
{
snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
errflag = 1;
return 1;
}
void *dlopen(const char *file, int mode)
{
return 0;
}
void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
{
return 0;
}
int __dladdr (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) {
snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
errflag = 1;
return -1;
}
*(struct link_map **)res = dso;
return 0;
}
char *dlerror()
{
if (!errflag) return 0;
errflag = 0;
return errbuf;
}
int dlclose(void *p)
{
return invalid_dso_handle(p);
}