NetBSD/libexec/ld.aout_so/rtld.c

/*	$NetBSD: rtld.c,v 1.75 1999/06/17 21:11:42 thorpej Exp $	*/

/*-
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Paul Kranenburg.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/errno.h>
#include <sys/mman.h>
#include <err.h>
#include <dlfcn.h>
#include <fcntl.h>
#include <a.out.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

#include "shlib.h"
#include "ld.h"

#ifdef __m68k__
/*
 * This is a slight hack to allow the same loader to be used on
 * 4k and 8k __LDPGSZ executables.
 */
static int page_size = 0x2000;
#undef PAGSIZ
#define PAGSIZ	page_size
#endif /* __m68k__ */

#ifndef MAP_ANON
#define MAP_ANON	0
#define anon_open() do {					\
	if ((anon_fd = open("/dev/zero", O_RDWR, 0)) == -1)	\
		err("open: %s", "/dev/zero");			\
} while (0)
#define anon_close() do {	\
	(void)close(anon_fd);	\
	anon_fd = -1;		\
} while (0)
#else
#define anon_open()
#define anon_close()
#endif

/*
 * Loader private data, hung off <so_map>->som_spd
 */
struct somap_private {
	int		spd_version;
	struct so_map	*spd_parent;
	int		spd_refcount;
	int		spd_flags;
#define _RTLD_MAIN	1	/* Marks the main program */
#define _RTLD_RTLD	2	/* Marks the run-time linker */
#define _RTLD_DL	4	/* A dlopen'ed object */
#define _RTLD_GLOBAL	8	/* Map is open to global search */
	size_t		spd_size;
	int		spd_symbolsize;
	long		spd_symbolbase;
	char		*spd_stringbase;

#ifdef SUN_COMPAT
	long		spd_offset;	/* Correction for Sun main programs */
#endif
};

#define LM_PRIVATE(smp)	((struct somap_private *)(smp)->som_spd)

#ifdef SUN_COMPAT
#define LM_OFFSET(smp)	(LM_PRIVATE(smp)->spd_offset)
#else
#define LM_OFFSET(smp)	(0)
#endif

/* Base address for section_dispatch_table entries */
#define LM_LDBASE(smp)	(smp->som_addr + LM_OFFSET(smp))

/* Start of text segment */
#define LM_TXTADDR(smp)	(smp->som_addr == (caddr_t)0 ? PAGSIZ : 0)

/* Start of run-time relocation_info */
#define LM_REL(smp)	((struct relocation_info *) \
	(smp->som_addr + LM_OFFSET(smp) + LD_REL((smp)->som_dynamic)))

/* Start of symbols */
#define LM_SYMBOLBASE(smp)	((long) \
	(smp->som_addr + LM_OFFSET(smp) + LD_SYMBOL((smp)->som_dynamic)))
#define LM_SYMBOL(smp, i)	((struct nzlist *) \
	(LM_PRIVATE(smp)->spd_symbolbase + \
	(i) * LM_PRIVATE(smp)->spd_symbolsize))

/* Start of hash table */
#define LM_HASH(smp)	((struct rrs_hash *) \
	((smp)->som_addr + LM_OFFSET(smp) + LD_HASH((smp)->som_dynamic)))

/* Start of strings */
#define LM_STRINGBASE(smp)	((char *) \
	((smp)->som_addr + LM_OFFSET(smp) + LD_STRINGS((smp)->som_dynamic)))

/* Start of search paths */
#define LM_PATHS(smp)	((char *) \
	((smp)->som_addr + LM_OFFSET(smp) + LD_PATHS((smp)->som_dynamic)))

/* End of text */
#define LM_ETEXT(smp)	((char *) \
	((smp)->som_addr + LM_TXTADDR(smp) + LD_TEXTSZ((smp)->som_dynamic)))

/* PLT is in data segment, so don't use LM_OFFSET here */
#define LM_PLT(smp)	((jmpslot_t *) \
	((smp)->som_addr + LD_PLT((smp)->som_dynamic)))

/* Parent of link map */
#define LM_PARENT(smp)	(LM_PRIVATE(smp)->spd_parent)

static char		__main_progname[] = "main";
static char		*main_progname = __main_progname;
static char		us[] = "/usr/libexec/ld.so";

char			**environ;
char			*__progname = us;
int			errno;

static uid_t		uid, euid;
static gid_t		gid, egid;
static int		careful;
static int		anon_fd = -1;

struct so_map		*link_map_head, *main_map;
struct so_map		**link_map_tail = &link_map_head;
struct rt_symbol	*rt_symbol_head;

static char		*ld_library_path;
static char		*ld_preload_path;
static int		no_intern_search;
static int		ld_suppress_warnings;
static int		ld_warn_non_pure_code;

static int		ld_tracing;

static void		*__dlopen __P((const char *, int));
static int		__dlclose __P((void *));
static void		*__dlsym __P((void *, const char *));
static int		__dlctl __P((void *, int, void *));
static void		__dlexit __P((void));
static int		__dladdr __P((void *, Dl_info *));

static struct ld_entry	ld_entry = {
	__dlopen, __dlclose, __dlsym, __dlctl, __dlexit, __dladdr
};

       void		xprintf __P((char *, ...));
       int		rtld __P((int, struct crt_ldso *, struct _dynamic *));
       void		binder_entry __P((void));
       long		binder __P((jmpslot_t *));
static int		load_subs __P((struct so_map *));
static struct so_map	*map_object __P((struct sod *, struct so_map *));
static void		unmap_object __P((struct so_map *));
static struct so_map	*alloc_link_map __P((	char *, struct sod *,
						struct so_map *, caddr_t,
						size_t, struct _dynamic *));
static void		free_link_map __P((struct so_map *));
static inline void	check_text_reloc __P((	struct relocation_info *,
						struct so_map *,
						caddr_t));
static void		init_maps __P((struct so_map *));
static void		reloc_map __P((struct so_map *));
static void		reloc_copy __P((struct so_map *));
static void		call_map __P((struct so_map *, char *));
static char		*rtfindlib __P((char *, int, int, int *, char *));
static struct nzlist	*lookup __P((	const char *, struct so_map *,
					struct so_map **, int));
static inline struct rt_symbol	*lookup_rts __P((const char *));
static struct rt_symbol	*enter_rts __P((const char *, long, int, caddr_t,
						long, struct so_map *));
static void		maphints __P((void));
static void		unmaphints __P((void));
static int		hash_string __P((const char *));
static int		hinthash __P((char *, int, int));
static char		*findhint __P((char *, int, int, char *));

static void		preload __P((char *));
static void		ld_trace __P((struct so_map *));
static void		build_sod __P((const char *, struct sod *));

static inline int
strcmp (register const char *s1, register const char *s2)
{
	while (*s1 == *s2++)
		if (*s1++ == 0)
			return (0);
	return (*(unsigned char *)s1 - *(unsigned char *)--s2);
}

/* `md-static-funcs.c' implements these functions: */
static void	md_relocate_simple __P((struct relocation_info *,
					long, char *));

#include "md-static-funcs.c"

/*
 * Called from assembler stub that has set up crtp (passed from crt0)
 * and dp (our __DYNAMIC).
 */
int
rtld(version, crtp, dp)
	int			version;
	struct crt_ldso		*crtp;
	struct _dynamic		*dp;
{
	int			n;
	int			nreloc;		/* # of ld.so relocations */
	struct relocation_info	*reloc;
	struct so_debug		*ddp;
	struct so_map		*smp;

	/* Check version */
	if (		version != CRT_VERSION_BSD_2 &&
			version != CRT_VERSION_BSD_3 &&
			version != CRT_VERSION_BSD_4 &&
			version != CRT_VERSION_SUN)
		return -1;

	/* Fixup __DYNAMIC structure */
	(long)dp->d_un.d_sdt += crtp->crt_ba;

	/* Divide by hand to avoid possible use of library division routine */
	for (	nreloc = 0, n = LD_RELSZ(dp);
		n > 0;
		n -= sizeof(struct relocation_info) ) nreloc++;

	
	/* Relocate ourselves */
	for (	reloc = (struct relocation_info *)(LD_REL(dp) + crtp->crt_ba);
		nreloc;
		nreloc--, reloc++) {

		register long	addr = reloc->r_address + crtp->crt_ba;

		md_relocate_simple(reloc, crtp->crt_ba, (char *)addr);
	}

	/* Now (and NOT BEFORE this point) we can call externals. */

	if (version >= CRT_VERSION_BSD_4)
		__progname = crtp->crt_ldso;

	if (version >= CRT_VERSION_BSD_3)
		main_progname = crtp->crt_prog;

	/* Setup out (private) environ variable */
	environ = crtp->crt_ep;

	/*
	 * Make sure we do not allow the library search path
	 * to be modified through the environment if we are
	 * running either setuid or setgid.
	 */
	uid = getuid(); euid = geteuid();
	gid = getgid(); egid = getegid();
	careful = (uid != euid) || (gid != egid);
	if (careful) {
		unsetenv("LD_LIBRARY_PATH");
		unsetenv("LD_PRELOAD");
	}

#ifdef __m68k__
	/*
	 * Locate the a.out header and check the machine ID.
	 * If we see MID_M68K4K, we alter the page size we
	 * use for address calculations.  This allows the
	 * same loader to be used for 4k and 8k executables
	 * and libraries.  Trust me; the world is a better
	 * place because this.
	 */
	{
		register long textaddr;
		register struct exec *eh;

		/* XXX Assume this is near the start of text. */
		textaddr = ((long)crtp->crt_bp) & ~0xFFF;
		eh = (struct exec *) textaddr;
#if 0
		xprintf("%s: textaddr is 0x%x\n", us, textaddr);
		xprintf("\t magic=0x%x\n", eh->a_midmag);
#endif
		/*
		 * Use this rather than N_PAGSIZ(), to be
		 * safe...
		 */
		if (N_GETMID((*eh)) == MID_M68K4K)
			page_size = 0x1000;
#if 0
		xprintf("\t page_size=%d\n", page_size);
#endif
	}
#endif /* __m68k__ */

	/* Setup directory search */
	ld_library_path = getenv("LD_LIBRARY_PATH");
	add_search_path(ld_library_path);
	if (getenv("LD_NOSTD_PATH") == NULL)
		std_search_path();

	ld_suppress_warnings = getenv("LD_SUPPRESS_WARNINGS") != NULL;
	ld_warn_non_pure_code = getenv("LD_WARN_NON_PURE_CODE") != NULL;

	no_intern_search = getenv("LD_NO_INTERN_SEARCH") != 0;

	anon_open();

	/*
	 * Init object administration. We start off with a map description
	 * for `main' and `rtld'.
	 */
	smp = alloc_link_map(main_progname, (struct sod *)0, (struct so_map *)0,
					(caddr_t)0, 0, crtp->crt_dp);
	LM_PRIVATE(smp)->spd_refcount++;
	LM_PRIVATE(smp)->spd_flags |= _RTLD_MAIN | _RTLD_GLOBAL;

	smp = alloc_link_map(us, (struct sod *)0, (struct so_map *)0,
					(caddr_t)crtp->crt_ba, 0, dp);
	LM_PRIVATE(smp)->spd_refcount++;
	LM_PRIVATE(smp)->spd_flags |= _RTLD_RTLD;

	/* Fill in some field in main's __DYNAMIC structure */
	if (version >= CRT_VERSION_BSD_4)
		crtp->crt_ldentry = &ld_entry;
	else
		crtp->crt_dp->d_entry = &ld_entry;


	/* Handle LD_PRELOAD's here */
	ld_preload_path = getenv("LD_PRELOAD");
	if (ld_preload_path != NULL)
		preload(ld_preload_path);

	/* Load subsidiary objects into the process address space */
	ld_tracing = (int)getenv("LD_TRACE_LOADED_OBJECTS");
	load_subs(link_map_head);
	if (ld_tracing) {
		ld_trace(link_map_head);
		exit(0);
	}

	init_maps(link_map_head);

	crtp->crt_dp->d_un.d_sdt->sdt_loaded = link_map_head->som_next;

	ddp = crtp->crt_dp->d_debug;
	ddp->dd_cc = rt_symbol_head;
	if (ddp->dd_in_debugger) {
		caddr_t	addr = (caddr_t)((long)crtp->crt_bp & (~(PAGSIZ - 1)));

		/* Set breakpoint for the benefit of debuggers */
		if (mprotect(addr, PAGSIZ,
				PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
			err(1, "Cannot set breakpoint (%s)", main_progname);
		}
		md_set_breakpoint((long)crtp->crt_bp, (long *)&ddp->dd_bpt_shadow);
		if (mprotect(addr, PAGSIZ, PROT_READ|PROT_EXEC) == -1) {
			err(1, "Cannot re-protect breakpoint (%s)",
				main_progname);
		}

		ddp->dd_bpt_addr = crtp->crt_bp;
		if (link_map_head)
			ddp->dd_sym_loaded = 1;
	}

	/* Close the hints file */
	unmaphints();

	/* Close our file descriptor */
	(void)close(crtp->crt_ldfd);
	anon_close();
	return 0;
}


static int
load_subs(smp)
	struct so_map	*smp;
{
	int flag = 0;

	/* Propagate _RTLD_GLOBAL parent flag */
	flag |= (LM_PRIVATE(smp)->spd_flags & _RTLD_GLOBAL);

	for (; smp; smp = smp->som_next) {
		struct sod	*sodp;
		long		next = 0;

		if (LM_PRIVATE(smp)->spd_flags & _RTLD_RTLD)
			continue;

		if (smp->som_dynamic)
			next = LD_NEED(smp->som_dynamic);

		while (next) {
			struct so_map	*newmap;

			sodp = (struct sod *)(LM_LDBASE(smp) + next);

			if ((newmap = map_object(sodp, smp)) == NULL) {
				if (!ld_tracing) {
					char *fmt = sodp->sod_library ?
						"%s: lib%s.so.%d.%d" :
						"%s: %s";
					err(1, fmt, main_progname,
						sodp->sod_name+LM_LDBASE(smp),
						sodp->sod_major,
						sodp->sod_minor);
				}
				newmap = alloc_link_map(NULL, sodp, smp, 0, 0, 0);
			}
			LM_PRIVATE(newmap)->spd_refcount++;
			/* Note: existing maps also acquire the new flag */
			LM_PRIVATE(newmap)->spd_flags |= flag;
			next = sodp->sod_next;
		}
	}
	return 0;
}

void
ld_trace(smp)
	struct so_map	*smp;
{
	char	*fmt1, *fmt2, *fmt, *main_local;
	int	c;

	if ((main_local = getenv("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
		main_local = "";

	if ((fmt1 = getenv("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
		fmt1 = "\t-l%o.%m => %p (%x)\n";

	if ((fmt2 = getenv("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
		fmt2 = "\t%o (%x)\n";

	for (; smp; smp = smp->som_next) {
		struct sod	*sodp;
		char		*name, *path;

		if ((sodp = smp->som_sod) == NULL)
			continue;

		name = (char *)sodp->sod_name;
		if (LM_PARENT(smp))
			name += (long)LM_LDBASE(LM_PARENT(smp));

		if ((path = smp->som_path) == NULL)
			path = "not found";

		fmt = sodp->sod_library ? fmt1 : fmt2;
		while ((c = *fmt++) != '\0') {
			switch (c) {
			default:
				putchar(c);
				continue;
			case '\\':
				switch (c = *fmt) {
				case '\0':
					continue;
				case 'n':
					putchar('\n');
					break;
				case 't':
					putchar('\t');
					break;
				}
				break;
			case '%':
				switch (c = *fmt) {
				case '\0':
					continue;
				case '%':
				default:
					putchar(c);
					break;
				case 'A':
					printf("%s", main_local);
					break;
				case 'a':
					printf("%s", main_progname);
					break;
				case 'o':
					printf("%s", name);
					break;
				case 'm':
					printf("%d", sodp->sod_major);
					break;
				case 'n':
					printf("%d", sodp->sod_minor);
					break;
				case 'p':
					printf("%s", path);
					break;
				case 'x':
					printf("%p", smp->som_addr);
					break;
				}
				break;
			}
			++fmt;
		}
	}
}

/*
 * Allocate a new link map for shared object NAME loaded at ADDR as a
 * result of the presence of link object LOP in the link map PARENT.
 */
static struct so_map *
alloc_link_map(path, sodp, parent, addr, size, dp)
	char		*path;
	struct sod	*sodp;
	struct so_map	*parent;
	caddr_t		addr;
	size_t		size;
	struct _dynamic	*dp;
{
	struct so_map		*smp;
	struct somap_private	*smpp;

	smpp = (struct somap_private *)xmalloc(sizeof(struct somap_private));
	smp = (struct so_map *)xmalloc(sizeof(struct so_map));
	smp->som_next = NULL;
	*link_map_tail = smp;
	link_map_tail = &smp->som_next;

	/*smp->som_sodbase = 0; NOT USED */
	smp->som_write = 0;
	smp->som_addr = addr;
	smp->som_path = path?strdup(path):NULL;
	smp->som_sod = sodp;
	smp->som_dynamic = dp;
	smp->som_spd = (caddr_t)smpp;

	smpp->spd_refcount = 0;
	smpp->spd_flags = 0;
	smpp->spd_parent = parent;
	smpp->spd_size = size;
	if (dp == NULL)
		return (smp);

/*XXX*/	if (addr == 0) main_map = smp;

#ifdef SUN_COMPAT
	smpp->spd_offset =
		(addr==0 && dp->d_version==LD_VERSION_SUN) ? PAGSIZ : 0;
#endif

	/*
	 * Pre-compute the location of symbol and string tables;
	 * they do not change while this object is loaded.
	 */
	smpp->spd_symbolsize = LD_VERSION_NZLIST_P(dp->d_version)
				? sizeof(struct nzlist)
				: sizeof(struct nlist);
	smpp->spd_symbolbase = LM_SYMBOLBASE(smp);
	smpp->spd_stringbase = LM_STRINGBASE(smp);

	return (smp);
}

/*
 * Free the link map for an object being unmapped.  The link map
 * has already been removed from the link map list, so it can't be used
 * after it's been unmapped.
 */
static void
free_link_map(smp)
	struct so_map	*smp;
{

	if ((LM_PRIVATE(smp)->spd_flags & _RTLD_DL) != 0) {
		/* free synthetic sod structure allocated in __dlopen() */
		free((char *)smp->som_sod->sod_name);
		free(smp->som_sod);
	}

	/* free the link map structure. */
	free(smp->som_spd);
	if (smp->som_path != NULL)
		free(smp->som_path);
	free(smp);
}

/*
 * Map object identified by link object SODP which was found
 * in link map SMP.
 */
static struct so_map *
map_object(sodp, smp)
	struct sod	*sodp;
	struct so_map	*smp;
{
	char		*name;
	struct _dynamic	*dp;
	char		*path, *ipath;
	int		fd;
	caddr_t		addr;
	struct exec	hdr;
	int		usehints = 0;
	struct so_map	*p;

	name = (char *)sodp->sod_name;
	if (smp)
		name += (long)LM_LDBASE(smp);

	if (sodp->sod_library) {
		usehints = 1;
again:
		if (smp == NULL || no_intern_search ||
		    LD_PATHS(smp->som_dynamic) == 0) {
			ipath = NULL;
		} else {
			ipath = LM_PATHS(smp);
			add_search_path(ipath);
		}

		path = rtfindlib(name, sodp->sod_major,
				 sodp->sod_minor, &usehints, ipath);
		if (ipath)
			remove_search_path(ipath);

		if (path == NULL) {
			errno = ENOENT;
			return NULL;
		}
	} else {
		if (careful && *name != '/') {
			errno = EACCES;
			return NULL;
		}
		path = name;
	}

	/* Check if already loaded */
	for (p = link_map_head; p; p = p->som_next)
		if (p->som_path && strcmp(p->som_path, path) == 0)
			break;

	if (p != NULL)
		return p;

	if ((fd = open(path, O_RDONLY, 0)) == -1) {
		if (usehints) {
			usehints = 0;
			goto again;
		}
		return NULL;
	}

	if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
		(void)close(fd);
		/*errno = x;*/
		return NULL;
	}

	if (N_BADMAG(hdr)) {
		(void)close(fd);
		errno = EFTYPE;
		return NULL;
	}

	if ((addr = mmap(0, hdr.a_text + hdr.a_data + hdr.a_bss,
	         PROT_READ|PROT_EXEC,
	         MAP_FILE|MAP_PRIVATE, fd, 0)) == (caddr_t)-1) {
		(void)close(fd);
		return NULL;
	}
#if DEBUG
	xprintf("map1: 0x%x for 0x%x\n", addr, hdr.a_text + hdr.a_data + hdr.a_bss);
#endif

	if (mprotect(addr + hdr.a_text, hdr.a_data,
	    PROT_READ|PROT_WRITE|PROT_EXEC) != 0) {
		(void)close(fd);
		return NULL;
	}

	if (mmap(addr + hdr.a_text + hdr.a_data, hdr.a_bss,
		 PROT_READ|PROT_WRITE|PROT_EXEC,
		 MAP_ANON|MAP_PRIVATE|MAP_FIXED,
		 anon_fd, 0) == (caddr_t)-1) {
		(void)close(fd);
		return NULL;
	}

	(void)close(fd);

	/* Assume _DYNAMIC is the first data item */
	dp = (struct _dynamic *)(addr+hdr.a_text);

	/* Fixup __DYNAMIC structure */
	(long)dp->d_un.d_sdt += (long)addr;

	return alloc_link_map(path, sodp, smp, addr,
	    hdr.a_text + hdr.a_data + hdr.a_bss, dp);
}

/*
 * Unmap a mapped object.
 */
static void
unmap_object(smp)
	struct so_map	*smp;
{
	struct so_map *p, **pp;

	/* remove from link map list */
	pp = &link_map_head;
	while ((p = *pp) != NULL) {
		if (p == smp)
			break;
		pp = &p->som_next;
	}
	if (p == NULL) {
		warnx("warning: link map entry for %s not on link map list!",
		    smp->som_path);
		return;
	}

	*pp = smp->som_next;			/* make list skip it */
	if (link_map_tail == &smp->som_next)	/* and readjust tail pointer */
		link_map_tail = pp;

	/* unmap from address space */
	(void)munmap(smp->som_addr, LM_PRIVATE(smp)->spd_size);
}

void
init_maps(head)
	struct so_map	*head;
{
	struct so_map	*smp;

	/* Relocate all loaded objects according to their RRS segments */
	for (smp = head; smp; smp = smp->som_next) {
		if (LM_PRIVATE(smp)->spd_flags & _RTLD_RTLD)
			continue;
		reloc_map(smp);
	}

	/* Copy any relocated initialized data. */
	for (smp = head; smp; smp = smp->som_next) {
		if (LM_PRIVATE(smp)->spd_flags & _RTLD_RTLD)
			continue;
		reloc_copy(smp);
	}

	/* Call any object initialization routines. */
	for (smp = head; smp; smp = smp->som_next) {
		if (LM_PRIVATE(smp)->spd_flags & _RTLD_RTLD)
			continue;
		call_map(smp, ".init");
		call_map(smp, "__init");
	}
}

static inline void
check_text_reloc(r, smp, addr)
	struct relocation_info	*r;
	struct so_map		*smp;
	caddr_t			addr;
{
	char	*sym;

	if (addr >= LM_ETEXT(smp))
		return;

	if (RELOC_EXTERN_P(r))
		sym = LM_PRIVATE(smp)->spd_stringbase +
		      LM_SYMBOL(smp, RELOC_SYMBOL(r))->nz_strx;
	else
		sym = "";

	if (ld_warn_non_pure_code && !ld_suppress_warnings)
		warnx("warning: non pure code in %s at %x (%s)",
				smp->som_path, r->r_address, sym);

	if (smp->som_write == 0 &&
		mprotect(smp->som_addr + LM_TXTADDR(smp),
				LD_TEXTSZ(smp->som_dynamic),
				PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {

		err(1, "Cannot enable writes to %s:%s",
					main_progname, smp->som_path);
	}

	smp->som_write = 1;
}

static void
reloc_map(smp)
	struct so_map		*smp;
{
	struct _dynamic		*dp = smp->som_dynamic;
	struct relocation_info	*r = LM_REL(smp);
	struct relocation_info	*rend = r + LD_RELSZ(dp)/sizeof(*r);
	long			symbolbase = LM_PRIVATE(smp)->spd_symbolbase;
	char			*stringbase = LM_PRIVATE(smp)->spd_stringbase;
	int			symsize = LM_PRIVATE(smp)->spd_symbolsize;

	if (LD_PLTSZ(dp))
		md_fix_jmpslot(LM_PLT(smp),
				(long)LM_PLT(smp), (long)binder_entry, 1);

	for (; r < rend; r++) {
		char	*sym;
		caddr_t	addr = smp->som_addr + r->r_address;

		check_text_reloc(r, smp, addr);

		if (RELOC_EXTERN_P(r)) {
			struct so_map	*src_map = NULL;
			struct nzlist	*p, *np;
			long	relocation = md_get_addend(r, addr);

			if (RELOC_LAZY_P(r))
				continue;

			p = (struct nzlist *)
				(symbolbase + symsize * RELOC_SYMBOL(r));

			if (p->nz_type == (N_SETV + N_EXT))
				src_map = smp;

			sym = stringbase + p->nz_strx;

#if defined(__arm32__) && 1 /* XXX MAGIC! */
			if (r->r_baserel && r->r_length == 2)
				relocation = 0;
#endif
			np = lookup(sym, smp, &src_map, 0/*XXX-jumpslots!*/);
			if (np == NULL)
				errx(1, "Undefined symbol \"%s\" in %s:%s\n",
					sym, main_progname, smp->som_path);

			/*
			 * Found symbol definition.
			 * If it's in a link map, adjust value
			 * according to the load address of that map.
			 * Otherwise it's a run-time allocated common
			 * whose value is already up-to-date.
			 */
			relocation += np->nz_value;
			if (src_map)
				relocation += (long)src_map->som_addr;

			if (RELOC_PCREL_P(r))
				relocation -= (long)smp->som_addr;

			if (RELOC_COPY_P(r) && src_map) {
				if (p->nz_size != np->nz_size)
					warnx("symbol %s at %p in %s changed "
					      "size: expected %ld, actual %ld",
					      sym,
					      src_map->som_addr + np->nz_value,
					      src_map->som_path,
					      p->nz_size, np->nz_size);
				(void)enter_rts(sym,
					(long)addr,
					N_DATA + N_EXT,
					src_map->som_addr + np->nz_value,
					p->nz_size, src_map);
				continue;
			}
			md_relocate(r, relocation, addr, 0);

		} else {
			md_relocate(r,
#ifdef SUN_COMPAT
				md_get_rt_segment_addend(r, addr)
#else
				md_get_addend(r, addr)
#endif
					+ (long)smp->som_addr, addr, 0);
		}

	}

	if (smp->som_write) {
		if (mprotect(smp->som_addr + LM_TXTADDR(smp),
				LD_TEXTSZ(smp->som_dynamic),
				PROT_READ|PROT_EXEC) == -1) {

			err(1, "Cannot disable writes to %s:%s\n",
						main_progname, smp->som_path);
		}
		smp->som_write = 0;
	}
}

static void
reloc_copy(smp)
	struct so_map		*smp;
{
	struct rt_symbol	*rtsp;

	for (rtsp = rt_symbol_head; rtsp; rtsp = rtsp->rt_next)
		if ((rtsp->rt_smp == NULL || rtsp->rt_smp == smp) &&
				rtsp->rt_sp->nz_type == N_DATA + N_EXT) {
			bcopy(rtsp->rt_srcaddr, (caddr_t)rtsp->rt_sp->nz_value,
							rtsp->rt_sp->nz_size);
		}
}

static void
call_map(smp, sym)
	struct so_map		*smp;
	char			*sym;
{
	struct so_map		*src_map = smp;
	struct nzlist		*np;

	np = lookup(sym, smp, &src_map, 1);
	if (np) {
#if DEBUG
xprintf("call_map: %s at %#x+%#x enter\n", sym, src_map->som_addr, np->nz_value);
#endif
#if defined(__arm32__) && 1 /* XXX MAGIC! */
	(*(void (*) __P((u_int)))(src_map->som_addr + np->nz_value))((u_int)src_map->som_addr);
#else
		(*(void (*) __P((void)))(src_map->som_addr + np->nz_value))();
#endif
#if DEBUG
xprintf("call_map: %s at %#x+%#x exit\n", sym, src_map->som_addr, np->nz_value);
#endif
	}
}

/*
 * Run-time common symbol table.
 */

#define RTC_TABSIZE		57
static struct rt_symbol 	*rt_symtab[RTC_TABSIZE];

/*
 * Compute hash value for run-time symbol table
 */
static inline int
hash_string(key)
	const char *key;
{
	const char *cp;
	int k;

	cp = key;
	k = 0;
	while (*cp)
		k = (((k << 1) + (k >> 14)) ^ (*cp++)) & 0x3fff;

	return k;
}

/*
 * Lookup KEY in the run-time common symbol table.
 */

static inline struct rt_symbol *
lookup_rts(key)
	const char *key;
{
	register int			hashval;
	register struct rt_symbol	*rtsp;

	/* Determine which bucket.  */

	hashval = hash_string(key) % RTC_TABSIZE;

	/* Search the bucket.  */

	for (rtsp = rt_symtab[hashval]; rtsp; rtsp = rtsp->rt_link)
		if (strcmp(key, rtsp->rt_sp->nz_name) == 0)
			return rtsp;

	return NULL;
}

static struct rt_symbol *
enter_rts(name, value, type, srcaddr, size, smp)
	const char	*name;
	long		value;
	int		type;
	caddr_t		srcaddr;
	long		size;
	struct so_map	*smp;
{
	register int			hashval;
	register struct rt_symbol	*rtsp, **rpp;

	/* Determine which bucket */
	hashval = hash_string(name) % RTC_TABSIZE;

	/* Find end of bucket */
	for (rpp = &rt_symtab[hashval]; *rpp; rpp = &(*rpp)->rt_link)
		;

	/* Allocate new common symbol */
	rtsp = (struct rt_symbol *)malloc(sizeof(struct rt_symbol));
	rtsp->rt_sp = (struct nzlist *)malloc(sizeof(struct nzlist));
	rtsp->rt_sp->nz_name = strdup(name);
	rtsp->rt_sp->nz_value = value;
	rtsp->rt_sp->nz_type = type;
	rtsp->rt_sp->nz_size = size;
	rtsp->rt_srcaddr = srcaddr;
	rtsp->rt_smp = smp;
	rtsp->rt_link = NULL;

	/* Link onto linear list as well */
	rtsp->rt_next = rt_symbol_head;
	rt_symbol_head = rtsp;

	*rpp = rtsp;

	return rtsp;
}


/*
 * Lookup NAME in the link maps. The link map producing a definition
 * is returned in SRC_MAP. If SRC_MAP is not NULL on entry the search is
 * confined to that map. If STRONG is set, the symbol returned must
 * have a proper type (used by binder()).
 */
static struct nzlist *
lookup(name, ref_map, src_map, strong)
	const char	*name;
	struct so_map	*ref_map;	/* map cont. the reference */
	struct so_map	**src_map;	/* map cont. the definition IN/OUT */
	int		strong;
{
	long			common_size = 0;
	struct so_map		*smp, *weak_smp;
	struct rt_symbol	*rtsp;
	struct	nzlist		*weak_np = 0;

	if ((rtsp = lookup_rts(name)) != NULL)
		return (rtsp->rt_sp);

	weak_smp = NULL; /* XXX - gcc! */

	/*
	 * Search all maps for a definition of NAME
	 */
	for (smp = link_map_head; smp; smp = smp->som_next) {
		int		buckets;
		long		hashval;
		struct rrs_hash	*hp;
		char		*cp;
		struct	nzlist	*np;

		/* Some local caching */
		long		symbolbase;
		struct rrs_hash	*hashbase;
		char		*stringbase;
		int		symsize;

		np = NULL; /* XXX - gcc! */

		if (*src_map && smp != *src_map)
			continue;

		/*
		 * When doing a global search, consider only maps
		 * marked for global lookup.
		 */
		if (*src_map == NULL && smp != ref_map &&
		    (LM_PRIVATE(smp)->spd_flags & _RTLD_GLOBAL) == 0)
			continue;

		if ((buckets = LD_BUCKETS(smp->som_dynamic)) == 0)
			continue; 

		if (LM_PRIVATE(smp)->spd_flags & _RTLD_RTLD)
			continue;

restart:
		/*
		 * Compute bucket in which the symbol might be found.
		 */
		for (hashval = 0, cp = (char *) name; *cp; cp++)
			hashval = (hashval << 1) + *cp;

		hashval = (hashval & 0x7fffffff) % buckets;

		hashbase = LM_HASH(smp);
		hp = hashbase + hashval;
		if (hp->rh_symbolnum == -1)
			/* Nothing in this bucket */
			continue;

		symbolbase = LM_PRIVATE(smp)->spd_symbolbase;
		stringbase = LM_PRIVATE(smp)->spd_stringbase;
		symsize = LM_PRIVATE(smp)->spd_symbolsize;

		while (hp) {
			np = (struct nzlist *)
				(symbolbase + hp->rh_symbolnum * symsize);
			cp = stringbase + np->nz_strx;
			if (strcmp(cp, name) == 0)
				break;
			if (hp->rh_next == 0)
				hp = NULL;
			else
				hp = hashbase + hp->rh_next;
		}
		if (hp == NULL)
			/* Nothing in this bucket */
			continue;

		/*
		 * We have a symbol with the name we're looking for.
		 */
		if (np->nz_type == N_INDR+N_EXT) {
			/*
			 * Next symbol gives the aliased name. Restart
			 * search with new name and confine to this map.
			 */
			name = stringbase + (++np)->nz_strx;
			*src_map = smp;
			goto restart;
		}

		if (np->nz_value == 0)
			/* It's not a definition */
			continue;

		if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
			if (N_AUX(&np->nlist) == AUX_FUNC) {
				/* It's a `weak' function definition */
				if (strong)
					continue;
			} else {
				/* It's a common, note value and continue search */
				if (common_size < np->nz_value)
					common_size = np->nz_value;
				continue;
			}
		}
		if (N_BIND(&np->nlist) == BIND_WEAK && weak_np == 0) {
			weak_np = np;
			weak_smp = smp;
			continue;
		}

		*src_map = smp;
		return np;
	}

	if (weak_np) {
		*src_map = weak_smp;
		return weak_np;
	}

	if (common_size == 0)
		/* Not found */
		return NULL;

	/*
	 * It's a common, enter into run-time common symbol table.
	 */
	rtsp = enter_rts(name, (long)calloc(1, common_size),
					N_UNDF + N_EXT, 0, common_size, NULL);

#if DEBUG
xprintf("Allocating common: %s size %d at %#x\n", name, common_size, rtsp->rt_sp->nz_value);
#endif

	return rtsp->rt_sp;
}

/*
 * Find the symbol in any mapped object that is closest to, but not
 * exceeds, the given address.
 */
static int
__dladdr(addr, dli)
	void	*addr;
	Dl_info	*dli;
{
	struct so_map		*smp;
	struct rt_symbol	*rtsp;
	int			i, found = 0;

	/*
	 * First look for an exact match in the commons table.
	 */
	for (i = 0; i < RTC_TABSIZE; i++) {
		for (rtsp = rt_symtab[i]; rtsp; rtsp = rtsp->rt_link)
			if (rtsp->rt_sp->nz_value == (long)addr) {
				dli->dli_fname = 0;
				dli->dli_fbase = 0;
				dli->dli_sname = rtsp->rt_sp->nz_name;
				dli->dli_saddr = addr;
				return (1);
			}
	}

	/*
	 * Search all symbols tables for a ADDR
	 */
	for (smp = link_map_head; smp; smp = smp->som_next) {
		struct so_map	*src_map = smp;
		int		buckets;
		struct rrs_hash	*hp;
		struct	nzlist	*np;
		caddr_t		cur = 0;

		/* Some local caching */
		long		symbolbase;
		struct rrs_hash	*hashbase;
		char		*stringbase;
		int		symsize;

#if 0
		if ((LM_PRIVATE(smp)->spd_flags & _RTLD_GLOBAL) == 0)
			continue;
#endif
		if (LM_PRIVATE(smp)->spd_flags & _RTLD_RTLD)
			continue;

		if ((caddr_t)addr < smp->som_addr)
			continue;

		np = lookup("_end", smp, &src_map, 1);
		if ((caddr_t)addr > np->nz_value + smp->som_addr)
			continue;

		if ((buckets = LD_BUCKETS(smp->som_dynamic)) == 0)
			continue; 

		/* 
		 * Walk the entire symbol table of this object
		 * in search for the nearest symbol.
		 */
		hashbase = LM_HASH(smp);
		symbolbase = LM_PRIVATE(smp)->spd_symbolbase;
		stringbase = LM_PRIVATE(smp)->spd_stringbase;
		symsize = LM_PRIVATE(smp)->spd_symbolsize;

		for (i = 0; i < buckets; i++) {
			hp = hashbase + i;
			if (hp->rh_symbolnum == -1)
				/* Nothing in this bucket */
				continue;

			while (hp) {
				caddr_t v;
				np = (struct nzlist *)
				     (symbolbase + hp->rh_symbolnum * symsize);

				hp = (hp->rh_next == 0)
					? NULL
					: hashbase + hp->rh_next;

				/* Skip any undefined symbol */
				if (np->nz_type == N_UNDF+N_EXT)
					continue;

				/* Compute absolute address */
				v = np->nz_value + src_map->som_addr;

				/*
				 * Make this symbol the new candidate if it
				 * is closer to, but not exceeding, ADDR.
				 */
				if (v >= cur && v <= (caddr_t)addr) {
					dli->dli_fname = smp->som_path;
					dli->dli_fbase = LM_LDBASE(smp);
					dli->dli_sname = stringbase +
								np->nz_strx;
					dli->dli_saddr = v;
					if (v == addr)
						return (1);
					cur = v;
					found = 1;
				}
			}
		}
		if (found)
			return (1);
	}

	return (0);
}

/*
 * This routine is called from the jumptable to resolve
 * procedure calls to shared objects.
 */
long
binder(jsp)
	jmpslot_t	*jsp;
{
	struct so_map	*smp, *src_map = NULL;
	long		addr;
	char		*sym;
	struct nzlist	*np;
	int		index;

	/*
	 * Find the PLT map that contains JSP.
	 */
	for (smp = link_map_head; smp; smp = smp->som_next) {
		if (LM_PLT(smp) < jsp &&
		    jsp < LM_PLT(smp) + LD_PLTSZ(smp->som_dynamic)/sizeof(*jsp))
			break;
	}

	if (smp == NULL)
		errx(1, "Call to binder from unknown location: %p\n", jsp);

	index = jsp->reloc_index & JMPSLOT_RELOC_MASK;

	/* Get the local symbol this jmpslot refers to */
	sym = LM_PRIVATE(smp)->spd_stringbase +
	      LM_SYMBOL(smp,RELOC_SYMBOL(&LM_REL(smp)[index]))->nz_strx;

	np = lookup(sym, smp, &src_map, 1);
	if (np == NULL)
		errx(1, "Undefined symbol \"%s\" called from %s:%s at %p",
				sym, main_progname, smp->som_path, jsp);

	/* Fixup jmpslot so future calls transfer directly to target */
	addr = np->nz_value;
	if (src_map)
		addr += (long)src_map->som_addr;

	md_fix_jmpslot(jsp, (long)jsp, addr, 0);

#if DEBUG
xprintf(" BINDER: %s located at %d(%p) = %#x in %s\n", sym, index, jsp, addr, src_map->som_path);
#endif
	return addr;
}


static int			hfd;
static size_t			hsize;
static struct hints_header	*hheader;
static struct hints_bucket	*hbuckets;
static char			*hstrtab;
static char			*hint_search_path = "";

#define HINTS_VALID (hheader != NULL && hheader != (struct hints_header *)-1)

static void
maphints()
{
	caddr_t		addr;
	struct stat	statbuf;

	if ((hfd = open(_PATH_LD_HINTS, O_RDONLY, 0)) == -1)
		goto nohints;

	if (fstat(hfd, &statbuf) != 0 ||
	    (hsize = (size_t)statbuf.st_size) < sizeof(struct hints_header))
		goto nohints;

	hsize = (hsize + PAGSIZ - 1) & -PAGSIZ;

	addr = mmap(0, hsize, PROT_READ, MAP_FILE|MAP_PRIVATE, hfd, 0);
	if (addr == (caddr_t)-1)
		goto nohints;

	hheader = (struct hints_header *)addr;
	if (HH_BADMAG(*hheader) || hheader->hh_ehints > hsize) {
		munmap(addr, hsize);
		goto nohints;
	}

	if (hheader->hh_version != LD_HINTS_VERSION_1 &&
	    hheader->hh_version != LD_HINTS_VERSION_2) {
		munmap(addr, hsize);
		goto nohints;
	}

	hbuckets = (struct hints_bucket *)(addr + hheader->hh_hashtab);
	hstrtab = (char *)(addr + hheader->hh_strtab);
	if (hheader->hh_version >= LD_HINTS_VERSION_2)
		hint_search_path = hstrtab + hheader->hh_dirlist;

	return;

nohints:
	if (hfd >= 0)
		close(hfd);
	hheader = (struct hints_header *)-1;
	return;
}

static void
unmaphints()
{

	if (HINTS_VALID) {
		munmap((caddr_t)hheader, hsize);
		close(hfd);
		hheader = NULL;
	}
}

int
hinthash(cp, vmajor, vminor)
	char	*cp;
	int	vmajor, vminor;
{
	int	k = 0;

	while (*cp)
		k = (((k << 1) + (k >> 14)) ^ (*cp++)) & 0x3fff;

	k = (((k << 1) + (k >> 14)) ^ (vmajor*257)) & 0x3fff;
	if (hheader->hh_version == LD_HINTS_VERSION_1)
		k = (((k << 1) + (k >> 14)) ^ (vminor*167)) & 0x3fff;

	return k;
}

#undef major
#undef minor

static char *
findhint(name, major, minor, prefered_path)
	char	*name;
	int	major, minor;
	char	*prefered_path;
{
	struct hints_bucket	*bp;

	bp = hbuckets + (hinthash(name, major, minor) % hheader->hh_nbucket);

	while (1) {
		/* Sanity check */
		if (bp->hi_namex >= hheader->hh_strtab_sz) {
			warnx("Bad name index: %#x\n", bp->hi_namex);
			break;
		}
		if (bp->hi_pathx >= hheader->hh_strtab_sz) {
			warnx("Bad path index: %#x\n", bp->hi_pathx);
			break;
		}

		if (strcmp(name, hstrtab + bp->hi_namex) == 0) {
			/* It's `name', check version numbers */
			if (bp->hi_major == major &&
				(bp->hi_ndewey < 2 || bp->hi_minor >= minor)) {
					if (prefered_path == NULL ||
					    strncmp(prefered_path,
						hstrtab + bp->hi_pathx,
						strlen(prefered_path)) == 0) {
						return hstrtab + bp->hi_pathx;
					}
			}
		}

		if (bp->hi_next == -1)
			break;

		/* Move on to next in bucket */
		bp = &hbuckets[bp->hi_next];
	}

	/* No hints available for name */
	return NULL;
}

static char *
rtfindlib(name, major, minor, usehints, ipath)
	char	*name;
	int	major, minor;
	int	*usehints;
	char	*ipath;
{
	register char	*cp;
	int		realminor;

	if (hheader == NULL)
		maphints();

	if (!HINTS_VALID || !(*usehints))
		goto lose;

	/* NOTE: `ipath' may reside in a piece of read-only memory */

	if (ld_library_path || ipath) {
		/* Prefer paths from some explicit LD_LIBRARY_PATH */
		register char	*lpath;
		char		*dp;

		dp = lpath = concat(ld_library_path ? ld_library_path : "",
				    (ld_library_path && ipath) ? ":" : "",
				    ipath ? ipath : "");

		while ((cp = strsep(&dp, ":")) != NULL) {
			cp = findhint(name, major, minor, cp);
			if (cp) {
				free(lpath);
				return cp;
			}
		}
		free(lpath);

		/*
		 * Not found in hints; try directory search now, before
		 * we get a spurious hint match below (i.e. a match not
		 * on one of the paths we're supposed to search first.
		 */
		realminor = -1;
		cp = (char *)findshlib(name, &major, &realminor, 0);
		if (cp && realminor >= minor)
			return cp;
	}

	/* No LD_LIBRARY_PATH or lib not found in there; check default */
	cp = findhint(name, major, minor, NULL);
	if (cp)
		return cp;

lose:
	/* No hints available for name */
	*usehints = 0;
	realminor = -1;
	add_search_path(hint_search_path);
	cp = (char *)findshlib(name, &major, &realminor, 0);
	remove_search_path(hint_search_path);
	if (cp) {
		if (realminor < minor && !ld_suppress_warnings)
			warnx("warning: lib%s.so.%d.%d: "
			      "minor version >= %d expected, using it anyway",
			      name, major, realminor, minor);
		return cp;
	}
	return NULL;
}

void
preload(paths)
	char		*paths;
{
	struct so_map	*nsmp;
	struct sod	*sodp;
	char		*cp, *dp;

	dp = paths = strdup(paths);
	if (dp == NULL) {
		errx(1, "preload: out of memory");
	}

	while ((cp = strsep(&dp, ":")) != NULL) {
		if ((sodp = (struct sod *)malloc(sizeof(struct sod))) == NULL) {
			errx(1, "preload: %s: out of memory", cp);
			return;
		}

		sodp->sod_name = (long)strdup(cp);
		sodp->sod_library = 0;
		sodp->sod_major = sodp->sod_minor = 0;

		if ((nsmp = map_object(sodp, 0)) == NULL) {
			errx(1, "preload: %s: cannot map object", cp);
		}
		LM_PRIVATE(nsmp)->spd_refcount++;
		LM_PRIVATE(nsmp)->spd_flags |= _RTLD_GLOBAL;
	}
	free(paths);
	return;
}

#if 0
static struct somap_private dlmap_private = {
		0,
		(struct so_map *)0,
		0,
#ifdef SUN_COMPAT
		0,
#endif
};

static struct so_map dlmap = {
	(caddr_t)0,
	"internal",
	(struct so_map *)0,
	(struct sod *)0,
	(caddr_t)0,
	(u_int)0,
	(struct _dynamic *)0,
	(caddr_t)&dlmap_private
};
#endif
static int dlerrno;

/*
 * Populate sod struct for dlopen's call to map_object
 */
void
build_sod(name, sodp)
	const char	*name;
	struct sod	*sodp;
{
	unsigned int	tuplet;
	int		major, minor;
	char		*realname = NULL, *tok, *etok, *cp;

	/* default is an absolute or relative path */
	sodp->sod_name = (long)strdup(name);    /* strtok is destructive */
	sodp->sod_library = 0;
	sodp->sod_major = sodp->sod_minor = 0;

	/* asking for lookup? */
	if (strncmp((char *)sodp->sod_name, "lib", 3) != 0)
		return;

	/* skip over 'lib' */
	cp = (char *)sodp->sod_name + 3;

	/* dot guardian */
	if ((strchr(cp, '.') == NULL) || (*(cp+strlen(cp)-1) == '.'))
		return;

	/* default */
	major = minor = -1;

	/* loop through name - parse skipping name */
	for (tuplet = 0; (tok = strsep(&cp, ".")) != NULL; tuplet++) {
		switch (tuplet) {
		case 0:
			/* removed 'lib' and extensions from name */
			realname = tok;
			break;
		case 1:
			/* 'so' extension */
			if (strcmp(tok, "so") != 0)
				goto backout;
			break;
		case 2:
			/* major version extension */
			major = strtol(tok, &etok, 10);
			if (*tok == '\0' || *etok != '\0')
				goto backout;
			break;
		case 3:
			/* minor version extension */
			minor = strtol(tok, &etok, 10);
			if (*tok == '\0' || *etok != '\0')
				goto backout;
			break;
		/* if we get here, it must be weird */
		default:
			goto backout;
		}
	}
	if (realname == NULL)
		goto backout;

	cp = (char *)sodp->sod_name;
	sodp->sod_name = (long)strdup(realname);
	free(cp);
	sodp->sod_library = 1;
	sodp->sod_major = major;
	sodp->sod_minor = minor;
	return;

backout:
	free((char *)sodp->sod_name);
	sodp->sod_name = (long)strdup(name);
}

static void *
__dlopen(name, mode)
	const char	*name;
	int		mode;
{
	struct sod	*sodp;
	struct so_map	*smp;

	/*
	 * A NULL argument returns the current set of mapped objects.
	 */
	if (name == NULL) {
		LM_PRIVATE(link_map_head)->spd_refcount++;
		/* Return magic token */
		return (void *)1;
	}

	if ((sodp = (struct sod *)malloc(sizeof(struct sod))) == NULL) {
		dlerrno = ENOMEM;
		return NULL;
	}

	build_sod(name, sodp);

	if ((smp = map_object(sodp, 0)) == NULL) {
#ifdef DEBUG
xprintf("%s: %s\n", name, strerror(errno));
#endif
		dlerrno = errno;
		free((char *)sodp->sod_name);
		free(sodp);
		return NULL;
	}
	if ((mode & RTLD_LOCAL) == 0)
		LM_PRIVATE(smp)->spd_flags |= _RTLD_GLOBAL;

	if (LM_PRIVATE(smp)->spd_refcount++ > 0) {
		free((char *)sodp->sod_name);
		free(sodp);
		return smp;
	}

	LM_PRIVATE(smp)->spd_flags |= _RTLD_DL;

	if (load_subs(smp) != 0) {
		if (--LM_PRIVATE(smp)->spd_refcount == 0) {
			unmap_object(smp);
			free_link_map(smp);
		}
		return NULL;
	}

	init_maps(smp);
	return smp;
}

static int
__dlclose(fd)
	void	*fd;
{
	struct so_map	*smp;

	if (fd == (void *)1)
		return 0;

	smp = (struct so_map *)fd;
#ifdef DEBUG
xprintf("dlclose(%s): refcount = %d\n", smp->som_path, LM_PRIVATE(smp)->spd_refcount);
#endif
	if (--LM_PRIVATE(smp)->spd_refcount != 0)
		return 0;

	if ((LM_PRIVATE(smp)->spd_flags & _RTLD_DL) == 0)
		return 0;

	/* Dismantle shared object map and descriptor */
	call_map(smp, "__fini");
#if 0
	unload_subs(smp);		/* XXX should unload implied objects */
#endif
	unmap_object(smp);
	free_link_map(smp);
	return 0;
}

static void *
__dlsym(fd, sym)
	void		*fd;
	const char	*sym;
{
	struct so_map	*smp, *src_map = NULL;
	struct nzlist	*np;
	long		addr;

	/*
	 * Restrict search to passed map if dlopen()ed.
	 */
	if (fd == (void *)1)
		smp = link_map_head;
	else
		src_map = smp = (struct so_map *)fd;

	np = lookup(sym, smp, &src_map, 1);
	if (np == NULL)
		return NULL;

	/* Fixup jmpslot so future calls transfer directly to target */
	addr = np->nz_value;
	if (src_map)
		addr += (long)src_map->som_addr;

	return (void *)addr;
}

static int
__dlctl(fd, cmd, arg)
	void *fd;
	int cmd;
	void *arg;
{

	switch (cmd) {
	case DL_GETERRNO:
		*(int *)arg = dlerrno;
		dlerrno = 0;
		return (0);
	default:
		dlerrno = EOPNOTSUPP;
		return (-1);
	}
	return (-1);
}

static void
__dlexit()
{
	struct so_map	*smp;

	/* Call any object initialization routines. */
	for (smp = link_map_head; smp; smp = smp->som_next) {
		if (LM_PRIVATE(smp)->spd_flags & _RTLD_RTLD)
			continue;
		call_map(smp, ".fini");
	}
}

void
#if __STDC__
xprintf(char *fmt, ...)
#else
xprintf(fmt, va_alist)
char	*fmt;
#endif
{
	char buf[256];
	va_list	ap;
#if __STDC__
	va_start(ap, fmt);
#else
	va_start(ap);
#endif

	vsprintf(buf, fmt, ap);
	(void)write(1, buf, strlen(buf));
	va_end(ap);
}