Add a "fork" of musl as //fusl.

fusl/src/ldso/dynlink.c

Index: fusl/src/ldso/dynlink.c
diff --git a/fusl/src/ldso/dynlink.c b/fusl/src/ldso/dynlink.c
new file mode 100644
index 0000000000000000000000000000000000000000..93e7d67e96a59d01f77a2d0a4f473da0b9d0bef8
--- /dev/null
+++ b/fusl/src/ldso/dynlink.c
@@ -0,0 +1,2000 @@
+#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 {
+#if DL_FDPIC
+	struct fdpic_loadmap *loadmap;
+#else
+	unsigned char *base;
+#endif
+	char *name;
+	size_t *dynv;
+	struct dso *next, *prev;
+
+	Phdr *phdr;
+	int phnum;
+	size_t phentsize;
+	int refcnt;
+	Sym *syms;
+	uint32_t *hashtab;
+	uint32_t *ghashtab;
+	int16_t *versym;
+	char *strings;
+	unsigned char *map;
+	size_t map_len;
+	dev_t dev;
+	ino_t ino;
+	signed char global;
+	char relocated;
+	char constructed;
+	char kernel_mapped;
+	struct dso **deps, *needed_by;
+	char *rpath_orig, *rpath;
+	struct tls_module tls;
+	size_t tls_id;
+	size_t relro_start, relro_end;
+	void **new_dtv;
+	unsigned char *new_tls;
+	volatile int new_dtv_idx, new_tls_idx;
+	struct td_index *td_index;
+	struct dso *fini_next;
+	char *shortname;
+#if DL_FDPIC
+	unsigned char *base;
+#else
+	struct fdpic_loadmap *loadmap;
+#endif
+	struct funcdesc {
+		void *addr;
+		size_t *got;
+	} *funcdescs;
+	size_t *got;
+	char buf[];
+};
+
+struct symdef {
+	Sym *sym;
+	struct dso *dso;
+};
+
+int __init_tp(void *);
+void __init_libc(char **, char *);
+void *__copy_tls(unsigned char *);
+
+__attribute__((__visibility__("hidden")))
+const char *__libc_get_version(void);
+
+static struct builtin_tls {
+	char c;
+	struct pthread pt;
+	void *space[16];
+} builtin_tls[1];
+#define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
+
+#define ADDEND_LIMIT 4096
+static size_t *saved_addends, *apply_addends_to;
+
+static struct dso ldso;
+static struct dso *head, *tail, *fini_head;
+static char *env_path, *sys_path;
+static unsigned long long gencnt;
+static int runtime;
+static int ldd_mode;
+static int ldso_fail;
+static int noload;
+static jmp_buf *rtld_fail;
+static pthread_rwlock_t lock;
+static struct debug debug;
+static struct tls_module *tls_tail;
+static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
+static size_t static_tls_cnt;
+static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
+static struct fdpic_loadmap *app_loadmap;
+static struct fdpic_dummy_loadmap app_dummy_loadmap;
+
+struct debug *_dl_debug_addr = &debug;
+
+__attribute__((__visibility__("hidden")))
+void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
+
+__attribute__((__visibility__("hidden")))
+extern void (*const __init_array_end)(void), (*const __fini_array_end)(void);
+
+weak_alias(__init_array_start, __init_array_end);
+weak_alias(__fini_array_start, __fini_array_end);
+
+static int dl_strcmp(const char *l, const char *r)
+{
+	for (; *l==*r && *l; l++, r++);
+	return *(unsigned char *)l - *(unsigned char *)r;
+}
+#define strcmp(l,r) dl_strcmp(l,r)
+
+/* Compute load address for a virtual address in a given dso. */
+#if DL_FDPIC
+static void *laddr(const struct dso *p, size_t v)
+{
+	size_t j=0;
+	if (!p->loadmap) return p->base + v;
+	for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
+	return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
+}
+#define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
+	laddr(p, v), (p)->got })
+#else
+#define laddr(p, v) (void *)((p)->base + (v))
+#define fpaddr(p, v) ((void (*)())laddr(p, v))
+#endif
+
+static void decode_vec(size_t *v, size_t *a, size_t cnt)
+{
+	size_t i;
+	for (i=0; i<cnt; i++) a[i] = 0;
+	for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
+		a[0] |= 1UL<<v[0];
+		a[v[0]] = v[1];
+	}
+}
+
+static int search_vec(size_t *v, size_t *r, size_t key)
+{
+	for (; v[0]!=key; v+=2)
+		if (!v[0]) return 0;
+	*r = v[1];
+	return 1;
+}
+
+static uint32_t sysv_hash(const char *s0)
+{
+	const unsigned char *s = (void *)s0;
+	uint_fast32_t h = 0;
+	while (*s) {
+		h = 16*h + *s++;
+		h ^= h>>24 & 0xf0;
+	}
+	return h & 0xfffffff;
+}
+
+static uint32_t gnu_hash(const char *s0)
+{
+	const unsigned char *s = (void *)s0;
+	uint_fast32_t h = 5381;
+	for (; *s; s++)
+		h += h*32 + *s;
+	return h;
+}
+
+static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
+{
+	size_t i;
+	Sym *syms = dso->syms;
+	uint32_t *hashtab = dso->hashtab;
+	char *strings = dso->strings;
+	for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
+		if ((!dso->versym || dso->versym[i] >= 0)
+		    && (!strcmp(s, strings+syms[i].st_name)))
+			return syms+i;
+	}
+	return 0;
+}
+
+static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
+{
+	uint32_t nbuckets = hashtab[0];
+	uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
+	uint32_t i = buckets[h1 % nbuckets];
+
+	if (!i) return 0;
+
+	uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
+
+	for (h1 |= 1; ; i++) {
+		uint32_t h2 = *hashval++;
+		if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
+		    && !strcmp(s, dso->strings + dso->syms[i].st_name))
+			return dso->syms+i;
+		if (h2 & 1) break;
+	}
+
+	return 0;
+}
+
+static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
+{
+	const size_t *bloomwords = (const void *)(hashtab+4);
+	size_t f = bloomwords[fofs & (hashtab[2]-1)];
+	if (!(f & fmask)) return 0;
+
+	f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
+	if (!(f & 1)) return 0;
+
+	return gnu_lookup(h1, hashtab, dso, s);
+}
+
+#define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
+#define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
+
+#ifndef ARCH_SYM_REJECT_UND
+#define ARCH_SYM_REJECT_UND(s) 0
+#endif
+
+static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
+{
+	uint32_t h = 0, gh, gho, *ght;
+	size_t ghm = 0;
+	struct symdef def = {0};
+	for (; dso; dso=dso->next) {
+		Sym *sym;
+		if (!dso->global) continue;
+		if ((ght = dso->ghashtab)) {
+			if (!ghm) {
+				gh = gnu_hash(s);
+				int maskbits = 8 * sizeof ghm;
+				gho = gh / maskbits;
+				ghm = 1ul << gh % maskbits;
+			}
+			sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
+		} else {
+			if (!h) h = sysv_hash(s);
+			sym = sysv_lookup(s, h, dso);
+		}
+		if (!sym) continue;
+		if (!sym->st_shndx)
+			if (need_def || (sym->st_info&0xf) == STT_TLS
+			    || ARCH_SYM_REJECT_UND(sym))
+				continue;
+		if (!sym->st_value)
+			if ((sym->st_info&0xf) != STT_TLS)
+				continue;
+		if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
+		if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
+
+		if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
+		def.sym = sym;
+		def.dso = dso;
+		if (sym->st_info>>4 == STB_GLOBAL) break;
+	}
+	return def;
+}
+
+__attribute__((__visibility__("hidden")))
+ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
+
+static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
+{
+	unsigned char *base = dso->base;
+	Sym *syms = dso->syms;
+	char *strings = dso->strings;
+	Sym *sym;
+	const char *name;
+	void *ctx;
+	int type;
+	int sym_index;
+	struct symdef def;
+	size_t *reloc_addr;
+	size_t sym_val;
+	size_t tls_val;
+	size_t addend;
+	int skip_relative = 0, reuse_addends = 0, save_slot = 0;
+
+	if (dso == &ldso) {
+		/* Only ldso's REL table needs addend saving/reuse. */
+		if (rel == apply_addends_to)
+			reuse_addends = 1;
+		skip_relative = 1;
+	}
+
+	for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
+		if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
+		type = R_TYPE(rel[1]);
+		if (type == REL_NONE) continue;
+		sym_index = R_SYM(rel[1]);
+		reloc_addr = laddr(dso, rel[0]);
+		if (sym_index) {
+			sym = syms + sym_index;
+			name = strings + sym->st_name;
+			ctx = type==REL_COPY ? head->next : head;
+			def = (sym->st_info&0xf) == STT_SECTION
+				? (struct symdef){ .dso = dso, .sym = sym }
+				: find_sym(ctx, name, type==REL_PLT);
+			if (!def.sym && (sym->st_shndx != SHN_UNDEF
+			    || sym->st_info>>4 != STB_WEAK)) {
+				error("Error relocating %s: %s: symbol not found",
+					dso->name, name);
+				if (runtime) longjmp(*rtld_fail, 1);
+				continue;
+			}
+		} else {
+			sym = 0;
+			def.sym = 0;
+			def.dso = dso;
+		}
+
+		if (stride > 2) {
+			addend = rel[2];
+		} else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
+			addend = 0;
+		} else if (reuse_addends) {
+			/* Save original addend in stage 2 where the dso
+			 * chain consists of just ldso; otherwise read back
+			 * saved addend since the inline one was clobbered. */
+			if (head==&ldso)
+				saved_addends[save_slot] = *reloc_addr;
+			addend = saved_addends[save_slot++];
+		} else {
+			addend = *reloc_addr;
+		}
+
+		sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
+		tls_val = def.sym ? def.sym->st_value : 0;
+
+		switch(type) {
+		case REL_NONE:
+			break;
+		case REL_OFFSET:
+			addend -= (size_t)reloc_addr;
+		case REL_SYMBOLIC:
+		case REL_GOT:
+		case REL_PLT:
+			*reloc_addr = sym_val + addend;
+			break;
+		case REL_RELATIVE:
+			*reloc_addr = (size_t)base + addend;
+			break;
+		case REL_SYM_OR_REL:
+			if (sym) *reloc_addr = sym_val + addend;
+			else *reloc_addr = (size_t)base + addend;
+			break;
+		case REL_COPY:
+			memcpy(reloc_addr, (void *)sym_val, sym->st_size);
+			break;
+		case REL_OFFSET32:
+			*(uint32_t *)reloc_addr = sym_val + addend
+				- (size_t)reloc_addr;
+			break;
+		case REL_FUNCDESC:
+			*reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
+				+ (def.sym - def.dso->syms)) : 0;
+			break;
+		case REL_FUNCDESC_VAL:
+			if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
+			else *reloc_addr = sym_val;
+			reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
+			break;
+		case REL_DTPMOD:
+			*reloc_addr = def.dso->tls_id;
+			break;
+		case REL_DTPOFF:
+			*reloc_addr = tls_val + addend - DTP_OFFSET;
+			break;
+#ifdef TLS_ABOVE_TP
+		case REL_TPOFF:
+			*reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
+			break;
+#else
+		case REL_TPOFF:
+			*reloc_addr = tls_val - def.dso->tls.offset + addend;
+			break;
+		case REL_TPOFF_NEG:
+			*reloc_addr = def.dso->tls.offset - tls_val + addend;
+			break;
+#endif
+		case REL_TLSDESC:
+			if (stride<3) addend = reloc_addr[1];
+			if (runtime && def.dso->tls_id >= static_tls_cnt) {
+				struct td_index *new = malloc(sizeof *new);
+				if (!new) {
+					error(
+					"Error relocating %s: cannot allocate TLSDESC for %s",
+					dso->name, sym ? name : "(local)" );
+					longjmp(*rtld_fail, 1);
+				}
+				new->next = dso->td_index;
+				dso->td_index = new;
+				new->args[0] = def.dso->tls_id;
+				new->args[1] = tls_val + addend;
+				reloc_addr[0] = (size_t)__tlsdesc_dynamic;
+				reloc_addr[1] = (size_t)new;
+			} else {
+				reloc_addr[0] = (size_t)__tlsdesc_static;
+#ifdef TLS_ABOVE_TP
+				reloc_addr[1] = tls_val + def.dso->tls.offset
+					+ TPOFF_K + addend;
+#else
+				reloc_addr[1] = tls_val - def.dso->tls.offset
+					+ addend;
+#endif
+			}
+			break;
+		default:
+			error("Error relocating %s: unsupported relocation type %d",
+				dso->name, type);
+			if (runtime) longjmp(*rtld_fail, 1);
+			continue;
+		}
+	}
+}
+
+/* A huge hack: to make up for the wastefulness of shared libraries
+ * needing at least a page of dirty memory even if they have no global
+ * data, we reclaim the gaps at the beginning and end of writable maps
+ * and "donate" them to the heap by setting up minimal malloc
+ * structures and then freeing them. */
+
+static void reclaim(struct dso *dso, size_t start, size_t end)
+{
+	size_t *a, *z;
+	if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
+	if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
+	start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
+	end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
+	if (start>end || end-start < 4*sizeof(size_t)) return;
+	a = laddr(dso, start);
+	z = laddr(dso, end);
+	a[-2] = 1;
+	a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
+	z[1] = 1;
+	free(a);
+}
+
+static void reclaim_gaps(struct dso *dso)
+{
+	Phdr *ph = dso->phdr;
+	size_t phcnt = dso->phnum;
+
+	if (DL_FDPIC) return; // FIXME
+	for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
+		if (ph->p_type!=PT_LOAD) continue;
+		if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
+		reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
+		reclaim(dso, ph->p_vaddr+ph->p_memsz,
+			ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
+	}
+}
+
+static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
+{
+	static int no_map_fixed;
+	char *q;
+	if (!no_map_fixed) {
+		q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
+		if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
+			return q;
+		no_map_fixed = 1;
+	}
+	/* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
+	if (flags & MAP_ANONYMOUS) {
+		memset(p, 0, n);
+		return p;
+	}
+	ssize_t r;
+	if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
+	for (q=p; n; q+=r, off+=r, n-=r) {
+		r = read(fd, q, n);
+		if (r < 0 && errno != EINTR) return MAP_FAILED;
+		if (!r) {
+			memset(q, 0, n);
+			break;
+		}
+	}
+	return p;
+}
+
+static void unmap_library(struct dso *dso)
+{
+	if (dso->loadmap) {
+		size_t i;
+		for (i=0; i<dso->loadmap->nsegs; i++) {
+			if (!dso->loadmap->segs[i].p_memsz)
+				continue;
+			munmap((void *)dso->loadmap->segs[i].addr,
+				dso->loadmap->segs[i].p_memsz);
+		}
+		free(dso->loadmap);
+	} else if (dso->map && dso->map_len) {
+		munmap(dso->map, dso->map_len);
+	}
+}
+
+static void *map_library(int fd, struct dso *dso)
+{
+	Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
+	void *allocated_buf=0;
+	size_t phsize;
+	size_t addr_min=SIZE_MAX, addr_max=0, map_len;
+	size_t this_min, this_max;
+	size_t nsegs = 0;
+	off_t off_start;
+	Ehdr *eh;
+	Phdr *ph, *ph0;
+	unsigned prot;
+	unsigned char *map=MAP_FAILED, *base;
+	size_t dyn=0;
+	size_t tls_image=0;
+	size_t i;
+
+	ssize_t l = read(fd, buf, sizeof buf);
+	eh = buf;
+	if (l<0) return 0;
+	if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
+		goto noexec;
+	phsize = eh->e_phentsize * eh->e_phnum;
+	if (phsize > sizeof buf - sizeof *eh) {
+		allocated_buf = malloc(phsize);
+		if (!allocated_buf) return 0;
+		l = pread(fd, allocated_buf, phsize, eh->e_phoff);
+		if (l < 0) goto error;
+		if (l != phsize) goto noexec;
+		ph = ph0 = allocated_buf;
+	} else if (eh->e_phoff + phsize > l) {
+		l = pread(fd, buf+1, phsize, eh->e_phoff);
+		if (l < 0) goto error;
+		if (l != phsize) goto noexec;
+		ph = ph0 = (void *)(buf + 1);
+	} else {
+		ph = ph0 = (void *)((char *)buf + eh->e_phoff);
+	}
+	for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
+		if (ph->p_type == PT_DYNAMIC) {
+			dyn = ph->p_vaddr;
+		} else if (ph->p_type == PT_TLS) {
+			tls_image = ph->p_vaddr;
+			dso->tls.align = ph->p_align;
+			dso->tls.len = ph->p_filesz;
+			dso->tls.size = ph->p_memsz;
+		} else if (ph->p_type == PT_GNU_RELRO) {
+			dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
+			dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
+		}
+		if (ph->p_type != PT_LOAD) continue;
+		nsegs++;
+		if (ph->p_vaddr < addr_min) {
+			addr_min = ph->p_vaddr;
+			off_start = ph->p_offset;
+			prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
+				((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
+				((ph->p_flags&PF_X) ? PROT_EXEC : 0));
+		}
+		if (ph->p_vaddr+ph->p_memsz > addr_max) {
+			addr_max = ph->p_vaddr+ph->p_memsz;
+		}
+	}
+	if (!dyn) goto noexec;
+	if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
+		dso->loadmap = calloc(1, sizeof *dso->loadmap
+			+ nsegs * sizeof *dso->loadmap->segs);
+		if (!dso->loadmap) goto error;
+		dso->loadmap->nsegs = nsegs;
+		for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
+			if (ph->p_type != PT_LOAD) continue;
+			prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
+				((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
+				((ph->p_flags&PF_X) ? PROT_EXEC : 0));
+			map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
+				prot, MAP_PRIVATE,
+				fd, ph->p_offset & -PAGE_SIZE);
+			if (map == MAP_FAILED) {
+				unmap_library(dso);
+				goto error;
+			}
+			dso->loadmap->segs[i].addr = (size_t)map +
+				(ph->p_vaddr & PAGE_SIZE-1);
+			dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
+			dso->loadmap->segs[i].p_memsz = ph->p_memsz;
+			i++;
+			if (prot & PROT_WRITE) {
+				size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
+					+ ph->p_filesz;
+				size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
+				size_t pgend = brk + ph->p_memsz - ph->p_filesz
+					+ PAGE_SIZE-1 & -PAGE_SIZE;
+				if (pgend > pgbrk && mmap_fixed(map+pgbrk,
+					pgend-pgbrk, prot,
+					MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
+					-1, off_start) == MAP_FAILED)
+					goto error;
+				memset(map + brk, 0, pgbrk-brk);
+			}
+		}
+		map = (void *)dso->loadmap->segs[0].addr;
+		map_len = 0;
+		goto done_mapping;
+	}
+	addr_max += PAGE_SIZE-1;
+	addr_max &= -PAGE_SIZE;
+	addr_min &= -PAGE_SIZE;
+	off_start &= -PAGE_SIZE;
+	map_len = addr_max - addr_min + off_start;
+	/* The first time, we map too much, possibly even more than
+	 * the length of the file. This is okay because we will not
+	 * use the invalid part; we just need to reserve the right
+	 * amount of virtual address space to map over later. */
+	map = DL_NOMMU_SUPPORT
+		? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
+			MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
+		: mmap((void *)addr_min, map_len, prot,
+			MAP_PRIVATE, fd, off_start);
+	if (map==MAP_FAILED) goto error;
+	dso->map = map;
+	dso->map_len = map_len;
+	/* If the loaded file is not relocatable and the requested address is
+	 * not available, then the load operation must fail. */
+	if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
+		errno = EBUSY;
+		goto error;
+	}
+	base = map - addr_min;
+	dso->phdr = 0;
+	dso->phnum = 0;
+	for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
+		if (ph->p_type != PT_LOAD) continue;
+		/* Check if the programs headers are in this load segment, and
+		 * if so, record the address for use by dl_iterate_phdr. */
+		if (!dso->phdr && eh->e_phoff >= ph->p_offset
+		    && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
+			dso->phdr = (void *)(base + ph->p_vaddr
+				+ (eh->e_phoff-ph->p_offset));
+			dso->phnum = eh->e_phnum;
+			dso->phentsize = eh->e_phentsize;
+		}
+		/* Reuse the existing mapping for the lowest-address LOAD */
+		if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
+			continue;
+		this_min = ph->p_vaddr & -PAGE_SIZE;
+		this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
+		off_start = ph->p_offset & -PAGE_SIZE;
+		prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
+			((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
+			((ph->p_flags&PF_X) ? PROT_EXEC : 0));
+		if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
+			goto error;
+		if (ph->p_memsz > ph->p_filesz) {
+			size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
+			size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
+			memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
+			if (pgbrk-(size_t)base < this_max && mmap_fixed((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
+				goto error;
+		}
+	}
+	for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
+		if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
+			if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
+			    && errno != ENOSYS)
+				goto error;
+			break;
+		}
+done_mapping:
+	dso->base = base;
+	dso->dynv = laddr(dso, dyn);
+	if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
+	if (!runtime) reclaim_gaps(dso);
+	free(allocated_buf);
+	return map;
+noexec:
+	errno = ENOEXEC;
+error:
+	if (map!=MAP_FAILED) unmap_library(dso);
+	free(allocated_buf);
+	return 0;
+}
+
+static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
+{
+	size_t l;
+	int fd;
+	for (;;) {
+		s += strspn(s, ":\n");
+		l = strcspn(s, ":\n");
+		if (l-1 >= INT_MAX) return -1;
+		if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
+			if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
+			switch (errno) {
+			case ENOENT:
+			case ENOTDIR:
+			case EACCES:
+			case ENAMETOOLONG:
+				break;
+			default:
+				/* Any negative value but -1 will inhibit
+				 * futher path search. */
+				return -2;
+			}
+		}
+		s += l;
+	}
+}
+
+static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
+{
+	size_t n, l;
+	const char *s, *t, *origin;
+	char *d;
+	if (p->rpath || !p->rpath_orig) return 0;
+	if (!strchr(p->rpath_orig, '$')) {
+		p->rpath = p->rpath_orig;
+		return 0;
+	}
+	n = 0;
+	s = p->rpath_orig;
+	while ((t=strchr(s, '$'))) {
+		if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
+			return 0;
+		s = t+1;
+		n++;
+	}
+	if (n > SSIZE_MAX/PATH_MAX) return 0;
+
+	if (p->kernel_mapped) {
+		/* $ORIGIN searches cannot be performed for the main program
+		 * when it is suid/sgid/AT_SECURE. This is because the
+		 * pathname is under the control of the caller of execve.
+		 * For libraries, however, $ORIGIN can be processed safely
+		 * since the library's pathname came from a trusted source
+		 * (either system paths or a call to dlopen). */
+		if (libc.secure)
+			return 0;
+		l = readlink("/proc/self/exe", buf, buf_size);
+		if (l == -1) switch (errno) {
+		case ENOENT:
+		case ENOTDIR:
+		case EACCES:
+			break;
+		default:
+			return -1;
+		}
+		if (l >= buf_size)
+			return 0;
+		buf[l] = 0;
+		origin = buf;
+	} else {
+		origin = p->name;
+	}
+	t = strrchr(origin, '/');
+	l = t ? t-origin : 0;
+	p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
+	if (!p->rpath) return -1;
+
+	d = p->rpath;
+	s = p->rpath_orig;
+	while ((t=strchr(s, '$'))) {
+		memcpy(d, s, t-s);
+		d += t-s;
+		memcpy(d, origin, l);
+		d += l;
+		/* It was determined previously that the '$' is followed
+		 * either by "ORIGIN" or "{ORIGIN}". */
+		s = t + 7 + 2*(t[1]=='{');
+	}
+	strcpy(d, s);
+	return 0;
+}
+
+static void decode_dyn(struct dso *p)
+{
+	size_t dyn[DYN_CNT];
+	decode_vec(p->dynv, dyn, DYN_CNT);
+	p->syms = laddr(p, dyn[DT_SYMTAB]);
+	p->strings = laddr(p, dyn[DT_STRTAB]);
+	if (dyn[0]&(1<<DT_HASH))
+		p->hashtab = laddr(p, dyn[DT_HASH]);
+	if (dyn[0]&(1<<DT_RPATH))
+		p->rpath_orig = p->strings + dyn[DT_RPATH];
+	if (dyn[0]&(1<<DT_RUNPATH))
+		p->rpath_orig = p->strings + dyn[DT_RUNPATH];
+	if (dyn[0]&(1<<DT_PLTGOT))
+		p->got = laddr(p, dyn[DT_PLTGOT]);
+	if (search_vec(p->dynv, dyn, DT_GNU_HASH))
+		p->ghashtab = laddr(p, *dyn);
+	if (search_vec(p->dynv, dyn, DT_VERSYM))
+		p->versym = laddr(p, *dyn);
+}
+
+static size_t count_syms(struct dso *p)
+{
+	if (p->hashtab) return p->hashtab[1];
+
+	size_t nsym, i;
+	uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
+	uint32_t *hashval;
+	for (i = nsym = 0; i < p->ghashtab[0]; i++) {
+		if (buckets[i] > nsym)
+			nsym = buckets[i];
+	}
+	if (nsym) {
+		hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
+		do nsym++;
+		while (!(*hashval++ & 1));
+	}
+	return nsym;
+}
+
+static void *dl_mmap(size_t n)
+{
+	void *p;
+	int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
+#ifdef SYS_mmap2
+	p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
+#else
+	p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
+#endif
+	return p == MAP_FAILED ? 0 : p;
+}
+
+static void makefuncdescs(struct dso *p)
+{
+	static int self_done;
+	size_t nsym = count_syms(p);
+	size_t i, size = nsym * sizeof(*p->funcdescs);
+
+	if (!self_done) {
+		p->funcdescs = dl_mmap(size);
+		self_done = 1;
+	} else {
+		p->funcdescs = malloc(size);
+	}
+	if (!p->funcdescs) {
+		if (!runtime) a_crash();
+		error("Error allocating function descriptors for %s", p->name);
+		longjmp(*rtld_fail, 1);
+	}
+	for (i=0; i<nsym; i++) {
+		if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
+			p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
+			p->funcdescs[i].got = p->got;
+		} else {
+			p->funcdescs[i].addr = 0;
+			p->funcdescs[i].got = 0;
+		}
+	}
+}
+
+static struct dso *load_library(const char *name, struct dso *needed_by)
+{
+	char buf[2*NAME_MAX+2];
+	const char *pathname;
+	unsigned char *map;
+	struct dso *p, temp_dso = {0};
+	int fd;
+	struct stat st;
+	size_t alloc_size;
+	int n_th = 0;
+	int is_self = 0;
+
+	if (!*name) {
+		errno = EINVAL;
+		return 0;
+	}
+
+	/* Catch and block attempts to reload the implementation itself */
+	if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
+		static const char *rp, reserved[] =
+			"c\0pthread\0rt\0m\0dl\0util\0xnet\0";
+		char *z = strchr(name, '.');
+		if (z) {
+			size_t l = z-name;
+			for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
+			if (*rp) {
+				if (ldd_mode) {
+					/* Track which names have been resolved
+					 * and only report each one once. */
+					static unsigned reported;
+					unsigned mask = 1U<<(rp-reserved);
+					if (!(reported & mask)) {
+						reported |= mask;
+						dprintf(1, "\t%s => %s (%p)\n",
+							name, ldso.name,
+							ldso.base);
+					}
+				}
+				is_self = 1;
+			}
+		}
+	}
+	if (!strcmp(name, ldso.name)) is_self = 1;
+	if (is_self) {
+		if (!ldso.prev) {
+			tail->next = &ldso;
+			ldso.prev = tail;
+			tail = ldso.next ? ldso.next : &ldso;
+		}
+		return &ldso;
+	}
+	if (strchr(name, '/')) {
+		pathname = name;
+		fd = open(name, O_RDONLY|O_CLOEXEC);
+	} else {
+		/* Search for the name to see if it's already loaded */
+		for (p=head->next; p; p=p->next) {
+			if (p->shortname && !strcmp(p->shortname, name)) {
+				p->refcnt++;
+				return p;
+			}
+		}
+		if (strlen(name) > NAME_MAX) return 0;
+		fd = -1;
+		if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
+		for (p=needed_by; fd == -1 && p; p=p->needed_by) {
+			if (fixup_rpath(p, buf, sizeof buf) < 0)
+				fd = -2; /* Inhibit further search. */
+			if (p->rpath)
+				fd = path_open(name, p->rpath, buf, sizeof buf);
+		}
+		if (fd == -1) {
+			if (!sys_path) {
+				char *prefix = 0;
+				size_t prefix_len;
+				if (ldso.name[0]=='/') {
+					char *s, *t, *z;
+					for (s=t=z=ldso.name; *s; s++)
+						if (*s=='/') z=t, t=s;
+					prefix_len = z-ldso.name;
+					if (prefix_len < PATH_MAX)
+						prefix = ldso.name;
+				}
+				if (!prefix) {
+					prefix = "";
+					prefix_len = 0;
+				}
+				char etc_ldso_path[prefix_len + 1
+					+ sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
+				snprintf(etc_ldso_path, sizeof etc_ldso_path,
+					"%.*s/etc/ld-musl-" LDSO_ARCH ".path",
+					(int)prefix_len, prefix);
+				FILE *f = fopen(etc_ldso_path, "rbe");
+				if (f) {
+					if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
+						free(sys_path);
+						sys_path = "";
+					}
+					fclose(f);
+				} else if (errno != ENOENT) {
+					sys_path = "";
+				}
+			}
+			if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
+			fd = path_open(name, sys_path, buf, sizeof buf);
+		}
+		pathname = buf;
+	}
+	if (fd < 0) return 0;
+	if (fstat(fd, &st) < 0) {
+		close(fd);
+		return 0;
+	}
+	for (p=head->next; p; p=p->next) {
+		if (p->dev == st.st_dev && p->ino == st.st_ino) {
+			/* If this library was previously loaded with a
+			 * pathname but a search found the same inode,
+			 * setup its shortname so it can be found by name. */
+			if (!p->shortname && pathname != name)
+				p->shortname = strrchr(p->name, '/')+1;
+			close(fd);
+			p->refcnt++;
+			return p;
+		}
+	}
+	map = noload ? 0 : map_library(fd, &temp_dso);
+	close(fd);
+	if (!map) return 0;
+
+	/* Allocate storage for the new DSO. When there is TLS, this
+	 * storage must include a reservation for all pre-existing
+	 * threads to obtain copies of both the new TLS, and an
+	 * extended DTV capable of storing an additional slot for
+	 * the newly-loaded DSO. */
+	alloc_size = sizeof *p + strlen(pathname) + 1;
+	if (runtime && temp_dso.tls.image) {
+		size_t per_th = temp_dso.tls.size + temp_dso.tls.align
+			+ sizeof(void *) * (tls_cnt+3);
+		n_th = libc.threads_minus_1 + 1;
+		if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
+		else alloc_size += n_th * per_th;
+	}
+	p = calloc(1, alloc_size);
+	if (!p) {
+		unmap_library(&temp_dso);
+		return 0;
+	}
+	memcpy(p, &temp_dso, sizeof temp_dso);
+	decode_dyn(p);
+	p->dev = st.st_dev;
+	p->ino = st.st_ino;
+	p->refcnt = 1;
+	p->needed_by = needed_by;
+	p->name = p->buf;
+	strcpy(p->name, pathname);
+	/* Add a shortname only if name arg was not an explicit pathname. */
+	if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
+	if (p->tls.image) {
+		p->tls_id = ++tls_cnt;
+		tls_align = MAXP2(tls_align, p->tls.align);
+#ifdef TLS_ABOVE_TP
+		p->tls.offset = tls_offset + ( (tls_align-1) &
+			-(tls_offset + (uintptr_t)p->tls.image) );
+		tls_offset += p->tls.size;
+#else
+		tls_offset += p->tls.size + p->tls.align - 1;
+		tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
+			& (p->tls.align-1);
+		p->tls.offset = tls_offset;
+#endif
+		p->new_dtv = (void *)(-sizeof(size_t) &
+			(uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
+		p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
+		if (tls_tail) tls_tail->next = &p->tls;
+		else libc.tls_head = &p->tls;
+		tls_tail = &p->tls;
+	}
+
+	tail->next = p;
+	p->prev = tail;
+	tail = p;
+
+	if (DL_FDPIC) makefuncdescs(p);
+
+	if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
+
+	return p;
+}
+
+static void load_deps(struct dso *p)
+{
+	size_t i, ndeps=0;
+	struct dso ***deps = &p->deps, **tmp, *dep;
+	for (; p; p=p->next) {
+		for (i=0; p->dynv[i]; i+=2) {
+			if (p->dynv[i] != DT_NEEDED) continue;
+			dep = load_library(p->strings + p->dynv[i+1], p);
+			if (!dep) {
+				error("Error loading shared library %s: %m (needed by %s)",
+					p->strings + p->dynv[i+1], p->name);
+				if (runtime) longjmp(*rtld_fail, 1);
+				continue;
+			}
+			if (runtime) {
+				tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
+				if (!tmp) longjmp(*rtld_fail, 1);
+				tmp[ndeps++] = dep;
+				tmp[ndeps] = 0;
+				*deps = tmp;
+			}
+		}
+	}
+}
+
+static void load_preload(char *s)
+{
+	int tmp;
+	char *z;
+	for (z=s; *z; s=z) {
+		for (   ; *s && (isspace(*s) || *s==':'); s++);
+		for (z=s; *z && !isspace(*z) && *z!=':'; z++);
+		tmp = *z;
+		*z = 0;
+		load_library(s, 0);
+		*z = tmp;
+	}
+}
+
+static void make_global(struct dso *p)
+{
+	for (; p; p=p->next) p->global = 1;
+}
+
+static void do_mips_relocs(struct dso *p, size_t *got)
+{
+	size_t i, j, rel[2];
+	unsigned char *base = p->base;
+	i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
+	if (p==&ldso) {
+		got += i;
+	} else {
+		while (i--) *got++ += (size_t)base;
+	}
+	j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
+	i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
+	Sym *sym = p->syms + j;
+	rel[0] = (unsigned char *)got - base;
+	for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
+		rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
+		do_relocs(p, rel, sizeof rel, 2);
+	}
+}
+
+static void reloc_all(struct dso *p)
+{
+	size_t dyn[DYN_CNT];
+	for (; p; p=p->next) {
+		if (p->relocated) continue;
+		decode_vec(p->dynv, dyn, DYN_CNT);
+		if (NEED_MIPS_GOT_RELOCS)
+			do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
+		do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
+			2+(dyn[DT_PLTREL]==DT_RELA));
+		do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
+		do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
+
+		if (head != &ldso && p->relro_start != p->relro_end &&
+		    mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
+		    && errno != ENOSYS) {
+			error("Error relocating %s: RELRO protection failed: %m",
+				p->name);
+			if (runtime) longjmp(*rtld_fail, 1);
+		}
+
+		p->relocated = 1;
+	}
+}
+
+static void kernel_mapped_dso(struct dso *p)
+{
+	size_t min_addr = -1, max_addr = 0, cnt;
+	Phdr *ph = p->phdr;
+	for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
+		if (ph->p_type == PT_DYNAMIC) {
+			p->dynv = laddr(p, ph->p_vaddr);
+		} else if (ph->p_type == PT_GNU_RELRO) {
+			p->relro_start = ph->p_vaddr & -PAGE_SIZE;
+			p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
+		}
+		if (ph->p_type != PT_LOAD) continue;
+		if (ph->p_vaddr < min_addr)
+			min_addr = ph->p_vaddr;
+		if (ph->p_vaddr+ph->p_memsz > max_addr)
+			max_addr = ph->p_vaddr+ph->p_memsz;
+	}
+	min_addr &= -PAGE_SIZE;
+	max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
+	p->map = p->base + min_addr;
+	p->map_len = max_addr - min_addr;
+	p->kernel_mapped = 1;
+}
+
+void __libc_exit_fini()
+{
+	struct dso *p;
+	size_t dyn[DYN_CNT];
+	for (p=fini_head; p; p=p->fini_next) {
+		if (!p->constructed) continue;
+		decode_vec(p->dynv, dyn, DYN_CNT);
+		if (dyn[0] & (1<<DT_FINI_ARRAY)) {
+			size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
+			size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
+			while (n--) ((void (*)(void))*--fn)();
+		}
+#ifndef NO_LEGACY_INITFINI
+		if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
+			fpaddr(p, dyn[DT_FINI])();
+#endif
+	}
+}
+
+static void do_init_fini(struct dso *p)
+{
+	size_t dyn[DYN_CNT];
+	int need_locking = libc.threads_minus_1;
+	/* Allow recursive calls that arise when a library calls
+	 * dlopen from one of its constructors, but block any
+	 * other threads until all ctors have finished. */
+	if (need_locking) pthread_mutex_lock(&init_fini_lock);
+	for (; p; p=p->prev) {
+		if (p->constructed) continue;
+		p->constructed = 1;
+		decode_vec(p->dynv, dyn, DYN_CNT);
+		if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
+			p->fini_next = fini_head;
+			fini_head = p;
+		}
+#ifndef NO_LEGACY_INITFINI
+		if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
+			fpaddr(p, dyn[DT_INIT])();
+#endif
+		if (dyn[0] & (1<<DT_INIT_ARRAY)) {
+			size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
+			size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
+			while (n--) ((void (*)(void))*fn++)();
+		}
+		if (!need_locking && libc.threads_minus_1) {
+			need_locking = 1;
+			pthread_mutex_lock(&init_fini_lock);
+		}
+	}
+	if (need_locking) pthread_mutex_unlock(&init_fini_lock);
+}
+
+void __libc_start_init(void)
+{
+	do_init_fini(tail);
+}
+
+static void dl_debug_state(void)
+{
+}
+
+weak_alias(dl_debug_state, _dl_debug_state);
+
+void __init_tls(size_t *auxv)
+{
+}
+
+__attribute__((__visibility__("hidden")))
+void *__tls_get_new(size_t *v)
+{
+	pthread_t self = __pthread_self();
+
+	/* Block signals to make accessing new TLS async-signal-safe */
+	sigset_t set;
+	__block_all_sigs(&set);
+	if (v[0]<=(size_t)self->dtv[0]) {
+		__restore_sigs(&set);
+		return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
+	}
+
+	/* This is safe without any locks held because, if the caller
+	 * is able to request the Nth entry of the DTV, the DSO list
+	 * must be valid at least that far out and it was synchronized
+	 * at program startup or by an already-completed call to dlopen. */
+	struct dso *p;
+	for (p=head; p->tls_id != v[0]; p=p->next);
+
+	/* Get new DTV space from new DSO if needed */
+	if (v[0] > (size_t)self->dtv[0]) {
+		void **newdtv = p->new_dtv +
+			(v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
+		memcpy(newdtv, self->dtv,
+			((size_t)self->dtv[0]+1) * sizeof(void *));
+		newdtv[0] = (void *)v[0];
+		self->dtv = self->dtv_copy = newdtv;
+	}
+
+	/* Get new TLS memory from all new DSOs up to the requested one */
+	unsigned char *mem;
+	for (p=head; ; p=p->next) {
+		if (!p->tls_id || self->dtv[p->tls_id]) continue;
+		mem = p->new_tls + (p->tls.size + p->tls.align)
+			* a_fetch_add(&p->new_tls_idx,1);
+		mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
+			& (p->tls.align-1);
+		self->dtv[p->tls_id] = mem;
+		memcpy(mem, p->tls.image, p->tls.len);
+		if (p->tls_id == v[0]) break;
+	}
+	__restore_sigs(&set);
+	return mem + v[1] + DTP_OFFSET;
+}
+
+static void update_tls_size()
+{
+	libc.tls_cnt = tls_cnt;
+	libc.tls_align = tls_align;
+	libc.tls_size = ALIGN(
+		(1+tls_cnt) * sizeof(void *) +
+		tls_offset +
+		sizeof(struct pthread) +
+		tls_align * 2,
+	tls_align);
+}
+
+/* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
+ * following stage 2 and stage 3 functions via primitive symbolic lookup
+ * since it does not have access to their addresses to begin with. */
+
+/* Stage 2 of the dynamic linker is called after relative relocations 
+ * have been processed. It can make function calls to static functions
+ * and access string literals and static data, but cannot use extern
+ * symbols. Its job is to perform symbolic relocations on the dynamic
+ * linker itself, but some of the relocations performed may need to be
+ * replaced later due to copy relocations in the main program. */
+
+__attribute__((__visibility__("hidden")))
+void __dls2(unsigned char *base, size_t *sp)
+{
+	if (DL_FDPIC) {
+		void *p1 = (void *)sp[-2];
+		void *p2 = (void *)sp[-1];
+		if (!p1) {
+			size_t *auxv, aux[AUX_CNT];
+			for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
+			decode_vec(auxv, aux, AUX_CNT);
+			if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
+			else ldso.base = (void *)(aux[AT_PHDR] & -4096);
+		}
+		app_loadmap = p2 ? p1 : 0;
+		ldso.loadmap = p2 ? p2 : p1;
+		ldso.base = laddr(&ldso, 0);
+	} else {
+		ldso.base = base;
+	}
+	Ehdr *ehdr = (void *)ldso.base;
+	ldso.name = ldso.shortname = "libc.so";
+	ldso.global = 1;
+	ldso.phnum = ehdr->e_phnum;
+	ldso.phdr = laddr(&ldso, ehdr->e_phoff);
+	ldso.phentsize = ehdr->e_phentsize;
+	kernel_mapped_dso(&ldso);
+	decode_dyn(&ldso);
+
+	if (DL_FDPIC) makefuncdescs(&ldso);
+
+	/* Prepare storage for to save clobbered REL addends so they
+	 * can be reused in stage 3. There should be very few. If
+	 * something goes wrong and there are a huge number, abort
+	 * instead of risking stack overflow. */
+	size_t dyn[DYN_CNT];
+	decode_vec(ldso.dynv, dyn, DYN_CNT);
+	size_t *rel = laddr(&ldso, dyn[DT_REL]);
+	size_t rel_size = dyn[DT_RELSZ];
+	size_t symbolic_rel_cnt = 0;
+	apply_addends_to = rel;
+	for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
+		if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
+	if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
+	size_t addends[symbolic_rel_cnt+1];
+	saved_addends = addends;
+
+	head = &ldso;
+	reloc_all(&ldso);
+
+	ldso.relocated = 0;
+
+	/* Call dynamic linker stage-3, __dls3, looking it up
+	 * symbolically as a barrier against moving the address
+	 * load across the above relocation processing. */
+	struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
+	if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
+	else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
+}
+
+/* Stage 3 of the dynamic linker is called with the dynamic linker/libc
+ * fully functional. Its job is to load (if not already loaded) and
+ * process dependencies and relocations for the main application and
+ * transfer control to its entry point. */
+
+_Noreturn void __dls3(size_t *sp)
+{
+	static struct dso app, vdso;
+	size_t aux[AUX_CNT], *auxv;
+	size_t i;
+	char *env_preload=0;
+	size_t vdso_base;
+	int argc = *sp;
+	char **argv = (void *)(sp+1);
+	char **argv_orig = argv;
+	char **envp = argv+argc+1;
+
+	/* Find aux vector just past environ[] and use it to initialize
+	 * global data that may be needed before we can make syscalls. */
+	__environ = envp;
+	for (i=argc+1; argv[i]; i++);
+	libc.auxv = auxv = (void *)(argv+i+1);
+	decode_vec(auxv, aux, AUX_CNT);
+	__hwcap = aux[AT_HWCAP];
+	libc.page_size = aux[AT_PAGESZ];
+	libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
+		|| aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
+
+	/* Setup early thread pointer in builtin_tls for ldso/libc itself to
+	 * use during dynamic linking. If possible it will also serve as the
+	 * thread pointer at runtime. */
+	libc.tls_size = sizeof builtin_tls;
+	libc.tls_align = tls_align;
+	if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
+		a_crash();
+	}
+
+	/* Only trust user/env if kernel says we're not suid/sgid */
+	if (!libc.secure) {
+		env_path = getenv("LD_LIBRARY_PATH");
+		env_preload = getenv("LD_PRELOAD");
+	}
+
+	/* If the main program was already loaded by the kernel,
+	 * AT_PHDR will point to some location other than the dynamic
+	 * linker's program headers. */
+	if (aux[AT_PHDR] != (size_t)ldso.phdr) {
+		size_t interp_off = 0;
+		size_t tls_image = 0;
+		/* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
+		Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
+		app.phnum = aux[AT_PHNUM];
+		app.phentsize = aux[AT_PHENT];
+		for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
+			if (phdr->p_type == PT_PHDR)
+				app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
+			else if (phdr->p_type == PT_INTERP)
+				interp_off = (size_t)phdr->p_vaddr;
+			else if (phdr->p_type == PT_TLS) {
+				tls_image = phdr->p_vaddr;
+				app.tls.len = phdr->p_filesz;
+				app.tls.size = phdr->p_memsz;
+				app.tls.align = phdr->p_align;
+			}
+		}
+		if (DL_FDPIC) app.loadmap = app_loadmap;
+		if (app.tls.size) app.tls.image = laddr(&app, tls_image);
+		if (interp_off) ldso.name = laddr(&app, interp_off);
+		if ((aux[0] & (1UL<<AT_EXECFN))
+		    && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
+			app.name = (char *)aux[AT_EXECFN];
+		else
+			app.name = argv[0];
+		kernel_mapped_dso(&app);
+	} else {
+		int fd;
+		char *ldname = argv[0];
+		size_t l = strlen(ldname);
+		if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
+		argv++;
+		while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
+			char *opt = argv[0]+2;
+			*argv++ = (void *)-1;
+			if (!*opt) {
+				break;
+			} else if (!memcmp(opt, "list", 5)) {
+				ldd_mode = 1;
+			} else if (!memcmp(opt, "library-path", 12)) {
+				if (opt[12]=='=') env_path = opt+13;
+				else if (opt[12]) *argv = 0;
+				else if (*argv) env_path = *argv++;
+			} else if (!memcmp(opt, "preload", 7)) {
+				if (opt[7]=='=') env_preload = opt+8;
+				else if (opt[7]) *argv = 0;
+				else if (*argv) env_preload = *argv++;
+			} else {
+				argv[0] = 0;
+			}
+		}
+		argv[-1] = (void *)(argc - (argv-argv_orig));
+		if (!argv[0]) {
+			dprintf(2, "musl libc\n"
+				"Version %s\n"
+				"Dynamic Program Loader\n"
+				"Usage: %s [options] [--] pathname%s\n",
+				__libc_get_version(), ldname,
+				ldd_mode ? "" : " [args]");
+			_exit(1);
+		}
+		fd = open(argv[0], O_RDONLY);
+		if (fd < 0) {
+			dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
+			_exit(1);
+		}
+		runtime = 1;
+		Ehdr *ehdr = (void *)map_library(fd, &app);
+		if (!ehdr) {
+			dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
+			_exit(1);
+		}
+		runtime = 0;
+		close(fd);
+		ldso.name = ldname;
+		app.name = argv[0];
+		aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
+		/* Find the name that would have been used for the dynamic
+		 * linker had ldd not taken its place. */
+		if (ldd_mode) {
+			for (i=0; i<app.phnum; i++) {
+				if (app.phdr[i].p_type == PT_INTERP)
+					ldso.name = laddr(&app, app.phdr[i].p_vaddr);
+			}
+			dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
+		}
+	}
+	if (app.tls.size) {
+		libc.tls_head = &app.tls;
+		app.tls_id = tls_cnt = 1;
+#ifdef TLS_ABOVE_TP
+		app.tls.offset = 0;
+		tls_offset = app.tls.size
+			+ ( -((uintptr_t)app.tls.image + app.tls.size)
+			& (app.tls.align-1) );
+#else
+		tls_offset = app.tls.offset = app.tls.size
+			+ ( -((uintptr_t)app.tls.image + app.tls.size)
+			& (app.tls.align-1) );
+#endif
+		tls_align = MAXP2(tls_align, app.tls.align);
+	}
+	app.global = 1;
+	decode_dyn(&app);
+	if (DL_FDPIC) {
+		makefuncdescs(&app);
+		if (!app.loadmap) {
+			app.loadmap = (void *)&app_dummy_loadmap;
+			app.loadmap->nsegs = 1;
+			app.loadmap->segs[0].addr = (size_t)app.map;
+			app.loadmap->segs[0].p_vaddr = (size_t)app.map
+				- (size_t)app.base;
+			app.loadmap->segs[0].p_memsz = app.map_len;
+		}
+		argv[-3] = (void *)app.loadmap;
+	}
+
+	/* Attach to vdso, if provided by the kernel */
+	if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
+		Ehdr *ehdr = (void *)vdso_base;
+		Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
+		vdso.phnum = ehdr->e_phnum;
+		vdso.phentsize = ehdr->e_phentsize;
+		for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
+			if (phdr->p_type == PT_DYNAMIC)
+				vdso.dynv = (void *)(vdso_base + phdr->p_offset);
+			if (phdr->p_type == PT_LOAD)
+				vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
+		}
+		vdso.name = "";
+		vdso.shortname = "linux-gate.so.1";
+		vdso.global = 1;
+		vdso.relocated = 1;
+		decode_dyn(&vdso);
+		vdso.prev = &ldso;
+		ldso.next = &vdso;
+	}
+
+	/* Initial dso chain consists only of the app. */
+	head = tail = &app;
+
+	/* Donate unused parts of app and library mapping to malloc */
+	reclaim_gaps(&app);
+	reclaim_gaps(&ldso);
+
+	/* Load preload/needed libraries, add their symbols to the global
+	 * namespace, and perform all remaining relocations. */
+	if (env_preload) load_preload(env_preload);
+	load_deps(&app);
+	make_global(&app);
+
+#ifndef DYNAMIC_IS_RO
+	for (i=0; app.dynv[i]; i+=2)
+		if (app.dynv[i]==DT_DEBUG)
+			app.dynv[i+1] = (size_t)&debug;
+#endif
+
+	/* The main program must be relocated LAST since it may contin
+	 * copy relocations which depend on libraries' relocations. */
+	reloc_all(app.next);
+	reloc_all(&app);
+
+	update_tls_size();
+	if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
+		void *initial_tls = calloc(libc.tls_size, 1);
+		if (!initial_tls) {
+			dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
+				argv[0], libc.tls_size);
+			_exit(127);
+		}
+		if (__init_tp(__copy_tls(initial_tls)) < 0) {
+			a_crash();
+		}
+	} else {
+		size_t tmp_tls_size = libc.tls_size;
+		pthread_t self = __pthread_self();
+		/* Temporarily set the tls size to the full size of
+		 * builtin_tls so that __copy_tls will use the same layout
+		 * as it did for before. Then check, just to be safe. */
+		libc.tls_size = sizeof builtin_tls;
+		if (__copy_tls((void*)builtin_tls) != self) a_crash();
+		libc.tls_size = tmp_tls_size;
+	}
+	static_tls_cnt = tls_cnt;
+
+	if (ldso_fail) _exit(127);
+	if (ldd_mode) _exit(0);
+
+	/* Switch to runtime mode: any further failures in the dynamic
+	 * linker are a reportable failure rather than a fatal startup
+	 * error. */
+	runtime = 1;
+
+	debug.ver = 1;
+	debug.bp = dl_debug_state;
+	debug.head = head;
+	debug.base = ldso.base;
+	debug.state = 0;
+	_dl_debug_state();
+
+	errno = 0;
+
+	CRTJMP((void *)aux[AT_ENTRY], argv-1);
+	for(;;);
+}
+
+void *dlopen(const char *file, int mode)
+{
+	struct dso *volatile p, *orig_tail, *next;
+	struct tls_module *orig_tls_tail;
+	size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
+	size_t i;
+	int cs;
+	jmp_buf jb;
+
+	if (!file) return head;
+
+	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+	pthread_rwlock_wrlock(&lock);
+	__inhibit_ptc();
+
+	p = 0;
+	orig_tls_tail = tls_tail;
+	orig_tls_cnt = tls_cnt;
+	orig_tls_offset = tls_offset;
+	orig_tls_align = tls_align;
+	orig_tail = tail;
+	noload = mode & RTLD_NOLOAD;
+
+	rtld_fail = &jb;
+	if (setjmp(*rtld_fail)) {
+		/* Clean up anything new that was (partially) loaded */
+		if (p && p->deps) for (i=0; p->deps[i]; i++)
+			if (p->deps[i]->global < 0)
+				p->deps[i]->global = 0;
+		for (p=orig_tail->next; p; p=next) {
+			next = p->next;
+			while (p->td_index) {
+				void *tmp = p->td_index->next;
+				free(p->td_index);
+				p->td_index = tmp;
+			}
+			free(p->funcdescs);
+			if (p->rpath != p->rpath_orig)
+				free(p->rpath);
+			free(p->deps);
+			unmap_library(p);
+			free(p);
+		}
+		if (!orig_tls_tail) libc.tls_head = 0;
+		tls_tail = orig_tls_tail;
+		tls_cnt = orig_tls_cnt;
+		tls_offset = orig_tls_offset;
+		tls_align = orig_tls_align;
+		tail = orig_tail;
+		tail->next = 0;
+		p = 0;
+		goto end;
+	} else p = load_library(file, head);
+
+	if (!p) {
+		error(noload ?
+			"Library %s is not already loaded" :
+			"Error loading shared library %s: %m",
+			file);
+		goto end;
+	}
+
+	/* First load handling */
+	if (!p->deps) {
+		load_deps(p);
+		if (p->deps) for (i=0; p->deps[i]; i++)
+			if (!p->deps[i]->global)
+				p->deps[i]->global = -1;
+		if (!p->global) p->global = -1;
+		reloc_all(p);
+		if (p->deps) for (i=0; p->deps[i]; i++)
+			if (p->deps[i]->global < 0)
+				p->deps[i]->global = 0;
+		if (p->global < 0) p->global = 0;
+	}
+
+	if (mode & RTLD_GLOBAL) {
+		if (p->deps) for (i=0; p->deps[i]; i++)
+			p->deps[i]->global = 1;
+		p->global = 1;
+	}
+
+	update_tls_size();
+	_dl_debug_state();
+	orig_tail = tail;
+end:
+	__release_ptc();
+	if (p) gencnt++;
+	pthread_rwlock_unlock(&lock);
+	if (p) do_init_fini(orig_tail);
+	pthread_setcancelstate(cs, 0);
+	return p;
+}
+
+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;
+}
+
+static void *addr2dso(size_t a)
+{
+	struct dso *p;
+	size_t i;
+	if (DL_FDPIC) for (p=head; p; p=p->next) {
+		i = count_syms(p);
+		if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
+			return p;
+	}
+	for (p=head; p; p=p->next) {
+		if (DL_FDPIC && p->loadmap) {
+			for (i=0; i<p->loadmap->nsegs; i++) {
+				if (a-p->loadmap->segs[i].p_vaddr
+				    < p->loadmap->segs[i].p_memsz)
+					return p;
+			}
+		} else {
+			if (a-(size_t)p->map < p->map_len)
+				return p;
+		}
+	}
+	return 0;
+}
+
+void *__tls_get_addr(size_t *);
+
+static void *do_dlsym(struct dso *p, const char *s, void *ra)
+{
+	size_t i;
+	uint32_t h = 0, gh = 0, *ght;
+	Sym *sym;
+	if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
+		if (p == RTLD_DEFAULT) {
+			p = head;
+		} else if (p == RTLD_NEXT) {
+			p = addr2dso((size_t)ra);
+			if (!p) p=head;
+			p = p->next;
+		}
+		struct symdef def = find_sym(p, s, 0);
+		if (!def.sym) goto failed;
+		if ((def.sym->st_info&0xf) == STT_TLS)
+			return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
+		if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
+			return def.dso->funcdescs + (def.sym - def.dso->syms);
+		return laddr(def.dso, def.sym->st_value);
+	}
+	if (invalid_dso_handle(p))
+		return 0;
+	if ((ght = p->ghashtab)) {
+		gh = gnu_hash(s);
+		sym = gnu_lookup(gh, ght, p, s);
+	} else {
+		h = sysv_hash(s);
+		sym = sysv_lookup(s, h, p);
+	}
+	if (sym && (sym->st_info&0xf) == STT_TLS)
+		return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
+	if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
+		return p->funcdescs + (sym - p->syms);
+	if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
+		return laddr(p, sym->st_value);
+	if (p->deps) for (i=0; p->deps[i]; i++) {
+		if ((ght = p->deps[i]->ghashtab)) {
+			if (!gh) gh = gnu_hash(s);
+			sym = gnu_lookup(gh, ght, p->deps[i], s);
+		} else {
+			if (!h) h = sysv_hash(s);
+			sym = sysv_lookup(s, h, p->deps[i]);
+		}
+		if (sym && (sym->st_info&0xf) == STT_TLS)
+			return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
+		if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
+			return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
+		if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
+			return laddr(p->deps[i], sym->st_value);
+	}
+failed:
+	error("Symbol not found: %s", s);
+	return 0;
+}
+
+int __dladdr(const void *addr, Dl_info *info)
+{
+	struct dso *p;
+	Sym *sym, *bestsym;
+	uint32_t nsym;
+	char *strings;
+	void *best = 0;
+
+	pthread_rwlock_rdlock(&lock);
+	p = addr2dso((size_t)addr);
+	pthread_rwlock_unlock(&lock);
+
+	if (!p) return 0;
+
+	sym = p->syms;
+	strings = p->strings;
+	nsym = count_syms(p);
+
+	if (DL_FDPIC) {
+		size_t idx = ((size_t)addr-(size_t)p->funcdescs)
+			/ sizeof(*p->funcdescs);
+		if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
+			best = p->funcdescs + idx;
+			bestsym = sym + idx;
+		}
+	}
+
+	if (!best) for (; nsym; nsym--, sym++) {
+		if (sym->st_value
+		 && (1<<(sym->st_info&0xf) & OK_TYPES)
+		 && (1<<(sym->st_info>>4) & OK_BINDS)) {
+			void *symaddr = laddr(p, sym->st_value);
+			if (symaddr > addr || symaddr < best)
+				continue;
+			best = symaddr;
+			bestsym = sym;
+			if (addr == symaddr)
+				break;
+		}
+	}
+
+	if (!best) return 0;
+
+	if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
+		best = p->funcdescs + (bestsym - p->syms);
+
+	info->dli_fname = p->name;
+	info->dli_fbase = p->base;
+	info->dli_sname = strings + bestsym->st_name;
+	info->dli_saddr = best;
+
+	return 1;
+}
+
+__attribute__((__visibility__("hidden")))
+void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
+{
+	void *res;
+	pthread_rwlock_rdlock(&lock);
+	res = do_dlsym(p, s, ra);
+	pthread_rwlock_unlock(&lock);
+	return res;
+}
+
+int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
+{
+	struct dso *current;
+	struct dl_phdr_info info;
+	int ret = 0;
+	for(current = head; current;) {
+		info.dlpi_addr      = (uintptr_t)current->base;
+		info.dlpi_name      = current->name;
+		info.dlpi_phdr      = current->phdr;
+		info.dlpi_phnum     = current->phnum;
+		info.dlpi_adds      = gencnt;
+		info.dlpi_subs      = 0;
+		info.dlpi_tls_modid = current->tls_id;
+		info.dlpi_tls_data  = current->tls.image;
+
+		ret = (callback)(&info, sizeof (info), data);
+
+		if (ret != 0) break;
+
+		pthread_rwlock_rdlock(&lock);
+		current = current->next;
+		pthread_rwlock_unlock(&lock);
+	}
+	return ret;
+}
+#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;
+}