Support for .weak (in addition to the N_INDR stab) for gcc/g++. Also deal

with the -R option and store the path in the dynamic header when specified.
The $LD_RUN_PATH environment variable is not checked yet.

While here, split up the code a bit more to enable more selective replacing
of GPL'ed components that are linked with ld.so with others.

Obtained from: NetBSD (mostly, the breakup is my fault)

5 files changed, 562 insertions, 19 deletions

diff --git a/libexec/rtld-aout/dynamic.h b/libexec/rtld-aout/dynamic.h
new file mode 100644
index 0000000..1231a62
--- /dev/null
+++ b/libexec/rtld-aout/dynamic.h
@@ -0,0 +1,377 @@
+/*
+ * Copyright (c) 1993 Paul Kranenburg
+ * All rights reserved.
+ *
+ * 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 Paul Kranenburg.
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ *
+ *	$Id$
+ */
+
+#ifndef __DYNAMIC_H__
+#define __DYNAMIC_H__
+
+#define SUN_COMPAT
+
+#include "md.h"
+#include "link.h"
+
+#ifndef RELOC_JMPTAB_P
+
+#define RELOC_JMPTAB_P(r)		((r)->r_jmptable)
+#define RELOC_BASEREL_P(r)		((r)->r_baserel)
+#define RELOC_RELATIVE_P(r)		((r)->r_relative)
+#define RELOC_COPY_P(r)			((r)->r_copy)
+#define RELOC_LAZY_P(r)			((r)->r_jmptable)
+
+#define CHECK_GOT_RELOC(r)		((r)->r_pcrel)
+#define RELOC_PIC_TYPE(r)		((r)->r_baserel? \
+						PIC_TYPE_LARGE:PIC_TYPE_NONE)
+#endif
+
+#ifndef RELOC_INIT_SEGMENT_RELOC
+#define RELOC_INIT_SEGMENT_RELOC(r)
+#endif
+
+#ifndef MAX_GOTOFF
+#define MAX_GOTOFF(x)	(LONG_MAX)
+#endif
+
+#ifndef MIN_GOTOFF
+#define MIN_GOTOFF(x)	(LONG_MIN)
+#endif
+
+/*
+ * Internal representation of relocation types
+ */
+#define RELTYPE_EXTERN		1
+#define RELTYPE_JMPSLOT		2
+#define RELTYPE_BASEREL		4
+#define RELTYPE_RELATIVE	8
+#define RELTYPE_COPY		16
+
+#define N_ISWEAK(p)		(N_BIND(p) & BIND_WEAK)
+
+typedef struct localsymbol {
+	struct nzlist		nzlist;		/* n[z]list from file */
+	struct glosym		*symbol;	/* Corresponding global symbol,
+						   if any */
+	struct localsymbol	*next;		/* List of definitions */
+	struct file_entry	*entry;		/* Backpointer to file */
+	long			gotslot_offset;	/* Position in GOT, if any */
+	int			symbolnum;	/* Position in output nlist */
+	int			flags;
+#define LS_L_SYMBOL		1	/* Local symbol starts with an `L' */
+#define LS_WRITE		2	/* Symbol goes in output symtable */
+#define LS_RENAME		4	/* xlat name to `<file>.<name>' */
+#define LS_HASGOTSLOT		8	/* This symbol has a GOT entry */
+#define LS_WARNING		16	/* Second part of a N_WARNING duo */
+} localsymbol_t;
+
+/*
+ * Global symbol data is recorded in these structures, one for each global
+ * symbol. They are found via hashing in 'symtab', which points to a vector
+ * of buckets. Each bucket is a chain of these structures through the link
+ * field.
+ *
+ * Rewritten version to support extra info for dynamic linking.
+ */
+
+struct glosym {
+	struct glosym	*link;	/* Next symbol hash bucket. */
+	char		*name;	/* Name of this symbol.  */
+	long		value;	/* Value of this symbol */
+	localsymbol_t	*refs;	/* Chain of local symbols from object
+				   files pertaining to this global
+				   symbol */
+	localsymbol_t	*sorefs;/* Same for local symbols from shared
+				   object files. */
+
+	char	*warning;	/* message, from N_WARNING nlists */
+	int	common_size;	/* Common size */
+	int	symbolnum;	/* Symbol index in output symbol table */
+	int	rrs_symbolnum;	/* Symbol index in RRS symbol table */
+
+	localsymbol_t	*def_lsp;	/* The local symbol that gave this
+					   global symbol its definition */
+
+	char	defined;	/* Definition of this symbol */
+	char	so_defined;	/* Definition of this symbol in a shared
+				   object. These go into the RRS symbol table */
+	u_char	undef_refs;	/* Count of number of "undefined"
+				   messages printed for this symbol */
+	u_char	mult_defs;	/* Same for "multiply defined" symbols */
+	struct glosym	*alias;	/* For symbols of type N_INDR, this
+				   points at the real symbol. */
+	int	setv_count;	/* Number of elements in N_SETV symbols */
+	int	size;		/* Size of this symbol (either from N_SIZE
+				   symbols or a from shared object's RRS */
+	int	aux;		/* Auxiliary type information conveyed in
+				   the `n_other' field of nlists */
+
+	/* The offset into one of the RRS tables, -1 if not used */
+	long	jmpslot_offset;
+	long	gotslot_offset;
+
+	long			flags;
+
+#define GS_DEFINED		0x1	/* Symbol has definition (notyetused)*/
+#define GS_REFERENCED		0x2	/* Symbol is referred to by something
+					   interesting */
+#define GS_TRACE		0x4	/* Symbol will be traced */
+#define GS_HASJMPSLOT		0x8	/*				 */
+#define GS_HASGOTSLOT		0x10	/* Some state bits concerning    */
+#define GS_CPYRELOCRESERVED	0x20	/* entries in GOT and PLT tables */
+#define GS_CPYRELOCCLAIMED	0x40	/*				 */
+#define GS_WEAK			0x80	/* Symbol is weakly defined */
+
+};
+#ifndef __symbol_defined__
+#define __symbol_defined__
+typedef struct glosym symbol;
+#endif
+
+/* The symbol hash table: a vector of SYMTABSIZE pointers to struct glosym. */
+extern symbol *symtab[];
+#define FOR_EACH_SYMBOL(i,sp) {					\
+	int i;							\
+	for (i = 0; i < SYMTABSIZE; i++) {				\
+		register symbol *sp;				\
+		for (sp = symtab[i]; sp; sp = sp->link)
+
+#define END_EACH_SYMBOL	}}
+
+extern symbol	*got_symbol;		/* the symbol __GLOBAL_OFFSET_TABLE_ */
+extern symbol	*dynamic_symbol;	/* the symbol __DYNAMIC */
+
+/*
+ * Each input file, and each library member ("subfile") being loaded, has a
+ * `file_entry' structure for it.
+ *
+ * For files specified by command args, these are contained in the vector which
+ * `file_table' points to.
+ *
+ * For library members, they are dynamically allocated, and chained through the
+ * `chain' field. The chain is found in the `subfiles' field of the
+ * `file_entry'. The `file_entry' objects for the members have `superfile'
+ * fields pointing to the one for the library.
+ *
+ * Rewritten version to support extra info for dynamic linking.
+ */
+
+struct file_entry {
+	char	*filename;	/* Name of this file.  */
+	/*
+	 * Name to use for the symbol giving address of text start Usually
+	 * the same as filename, but for a file spec'd with -l this is the -l
+	 * switch itself rather than the filename.
+	 */
+	char		*local_sym_name;
+	struct exec	header;	/* The file's a.out header.  */
+	localsymbol_t	*symbols;	/* Symbol table of the file. */
+	int		nsymbols;	/* Number of symbols in above array. */
+	int		string_size;	/* Size in bytes of string table. */
+	char		*strings;	/* Pointer to the string table when
+					   in core, NULL otherwise */
+	int		strings_offset;	/* Offset of string table,
+					   (normally N_STROFF() + 4) */
+	/*
+	 * Next two used only if `relocatable_output' or if needed for
+	 * output of undefined reference line numbers.
+	 */
+	struct relocation_info	*textrel;	/* Text relocations */
+	int			ntextrel;	/* # of text relocations */
+	struct relocation_info	*datarel;	/* Data relocations */
+	int			ndatarel;	/* # of data relocations */
+
+	/*
+	 * Relation of this file's segments to the output file.
+	 */
+	int 	text_start_address;	/* Start of this file's text segment
+					   in the output file core image. */
+	int	data_start_address;	/* Start of this file's data segment
+					   in the output file core image. */
+	int	bss_start_address;	/* Start of this file's bss segment
+					   in the output file core image. */
+	struct file_entry *subfiles;	/* For a library, points to chain of
+					   entries for the library members. */
+	struct file_entry *superfile;	/* For library member, points to the
+					   library's own entry.  */
+	struct file_entry *chain;	/* For library member, points to next
+					   entry for next member.  */
+	int	starting_offset;	/* For a library member, offset of the
+					   member within the archive. Zero for
+					   files that are not library members.*/
+	int	total_size;		/* Size of contents of this file,
+					   if library member. */
+#ifdef SUN_COMPAT
+	struct file_entry *silly_archive;/* For shared libraries which have
+					    a .sa companion */
+#endif
+	int	lib_major, lib_minor;	/* Version numbers of a shared object */
+
+	int	flags;
+#define E_IS_LIBRARY		1	/* File is a an archive */
+#define E_HEADER_VALID		2	/* File's header has been read */
+#define E_SEARCH_DIRS		4	/* Search directories for file */
+#define E_SEARCH_DYNAMIC	8	/* Search for shared libs allowed */
+#define E_JUST_SYMS		0x10	/* File is used for incremental load */
+#define E_DYNAMIC		0x20	/* File is a shared object */
+#define E_SCRAPPED		0x40	/* Ignore this file */
+#define E_SYMBOLS_USED		0x80	/* Symbols from this entry were used */
+#define E_SECONDCLASS		0x100	/* Shared object is a subsidiary */
+};
+
+/*
+ * Runtime Relocation Section (RRS).
+ * This describes the data structures that go into the output text and data
+ * segments to support the run-time linker. The RRS can be empty (plain old
+ * static linking), or can just exist of GOT and PLT entries (in case of
+ * statically linked PIC code).
+ */
+extern int		rrs_section_type;	/* What's in the RRS section */
+#define RRS_NONE	0
+#define RRS_PARTIAL	1
+#define RRS_FULL	2
+extern int		rrs_text_size;		/* Size of RRS text additions */
+extern int		rrs_text_start;		/* Location of above */
+extern int		rrs_data_size;		/* Size of RRS data additions */
+extern int		rrs_data_start;		/* Location of above */
+extern char		*rrs_search_paths;	/* `-L' RT paths */
+
+/* Version number to put in __DYNAMIC (set by -V) */
+extern int	soversion;
+#ifndef DEFAULT_SOVERSION
+#define DEFAULT_SOVERSION	LD_VERSION_BSD
+#endif
+
+extern int		pc_relocation;		/* Current PC reloc value */
+
+extern int		number_of_shobjs;	/* # of shared objects linked in */
+
+/* Current link mode */
+extern int		link_mode;
+#define DYNAMIC		1		/* Consider shared libraries */
+#define SYMBOLIC	2		/* Force symbolic resolution */
+#define FORCEARCHIVE	4		/* Force inclusion of all members
+					   of archives */
+#define SHAREABLE	8		/* Build a shared object */
+#define SILLYARCHIVE	16		/* Process .sa companions, if any */
+
+extern FILE		*outstream;	/* Output file. */
+extern struct exec	outheader;	/* Output file header. */
+extern int		magic;		/* Output file magic. */
+extern int		oldmagic;
+extern int		relocatable_output;
+extern int		pic_type;
+#define PIC_TYPE_NONE	0
+#define PIC_TYPE_SMALL	1
+#define PIC_TYPE_LARGE	2
+
+void	read_header __P((int, struct file_entry *));
+void	read_entry_symbols __P((int, struct file_entry *));
+void	read_entry_strings __P((int, struct file_entry *));
+void	read_entry_relocation __P((int, struct file_entry *));
+void	enter_file_symbols __P((struct file_entry *));
+void	read_file_symbols __P((struct file_entry *));
+int	set_element_prefixed_p __P((char *));
+int	text_offset __P((struct file_entry *));
+int	file_open __P((struct file_entry *));
+void	each_file __P((void (*)(), void *));
+void	each_full_file __P((void (*)(), void *));
+unsigned long	check_each_file __P((unsigned long (*)(), void *));
+void	mywrite __P((void *, int, int, FILE *));
+void	padfile __P((int, FILE *));
+
+/* In warnings.c: */
+void	perror_name __P((char *));
+void	perror_file __P((struct file_entry *));
+void	print_symbols __P((FILE *));
+char	*get_file_name __P((struct file_entry *));
+void	print_file_name __P((struct file_entry *, FILE *));
+void	prline_file_name __P((struct file_entry *, FILE *));
+int	do_warnings __P((FILE *));
+
+/* In etc.c: */
+#include "support.h"
+
+/* In symbol.c: */
+void	symtab_init __P((int));
+symbol	*getsym __P((char *)), *getsym_soft __P((char *));
+
+/* In lib.c: */
+void	search_library __P((int, struct file_entry *));
+void	read_shared_object __P((int, struct file_entry *));
+int	findlib __P((struct file_entry *));
+
+/* In shlib.c: */
+#include "shlib.h"
+
+/* In rrs.c: */
+void	init_rrs __P((void));
+int	rrs_add_shobj __P((struct file_entry *));
+void	alloc_rrs_reloc __P((struct file_entry *, symbol *));
+void	alloc_rrs_segment_reloc __P((struct file_entry *, struct relocation_info  *));
+void	alloc_rrs_jmpslot __P((struct file_entry *, symbol *));
+void	alloc_rrs_gotslot __P((struct file_entry *, struct relocation_info  *, localsymbol_t *));
+void	alloc_rrs_cpy_reloc __P((struct file_entry *, symbol *));
+
+int	claim_rrs_reloc __P((struct file_entry *, struct relocation_info *, symbol *, long *));
+long	claim_rrs_jmpslot __P((struct file_entry *, struct relocation_info *, symbol *, long));
+long	claim_rrs_gotslot __P((struct file_entry *, struct relocation_info *, struct localsymbol *, long));
+long	claim_rrs_internal_gotslot __P((struct file_entry *, struct relocation_info *, struct localsymbol *, long));
+void	claim_rrs_cpy_reloc __P((struct file_entry *, struct relocation_info *, symbol *));
+void	claim_rrs_segment_reloc __P((struct file_entry *, struct relocation_info *));
+void	consider_rrs_section_lengths __P((void));
+void	relocate_rrs_addresses __P((void));
+void	write_rrs __P((void));
+
+/* In <md>.c */
+void	md_init_header __P((struct exec *, int, int));
+long	md_get_addend __P((struct relocation_info *, unsigned char *));
+void	md_relocate __P((struct relocation_info *, long, unsigned char *, int));
+void	md_make_jmpslot __P((jmpslot_t *, long, long));
+void	md_fix_jmpslot __P((jmpslot_t *, long, u_long));
+int	md_make_reloc __P((struct relocation_info *, struct relocation_info *, int));
+void	md_make_jmpreloc __P((struct relocation_info *, struct relocation_info *, int));
+void	md_make_gotreloc __P((struct relocation_info *, struct relocation_info *, int));
+void	md_make_copyreloc __P((struct relocation_info *, struct relocation_info *));
+void	md_set_breakpoint __P((long, long *));
+
+#ifdef NEED_SWAP
+/* In xbits.c: */
+void	swap_longs __P((long *, int));
+void	swap_symbols __P((struct nlist *, int));
+void	swap_zsymbols __P((struct nzlist *, int));
+void	swap_ranlib_hdr __P((struct ranlib *, int));
+void	swap__dynamic __P((struct link_dynamic *));
+void	swap_section_dispatch_table __P((struct section_dispatch_table *));
+void	swap_so_debug __P((struct so_debug *));
+void	swapin_sod __P((struct sod *, int));
+void	swapout_sod __P((struct sod *, int));
+void	swapout_fshash __P((struct fshash *, int));
+#endif
+
+#endif /* __DYNAMIC_H__ */
diff --git a/libexec/rtld-aout/shlib.c b/libexec/rtld-aout/shlib.c
index 9460d35..44e30f0 100644
--- a/libexec/rtld-aout/shlib.c
+++ b/libexec/rtld-aout/shlib.c
@@ -27,28 +27,26 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *	$Id: shlib.c,v 1.14 1996/01/13 00:14:53 jdp Exp $
+ *	$Id: shlib.c,v 1.15 1996/04/20 18:27:56 jdp Exp $
  */
 
 #include <sys/param.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/file.h>
 #include <sys/time.h>
+#include <a.out.h>
+#include <ctype.h>
+#include <dirent.h>
 #include <err.h>
 #include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
-#include <ctype.h>
-#include <dirent.h>
-#include <a.out.h>
 
-#include "ld.h"
-
-#ifdef SUNOS4
-char	*strsep();
-#endif
+#include <link.h>
+#include "shlib.h"
+#include "support.h"
 
 /*
  * Standard directories to search for files specified by -l.
@@ -59,7 +57,7 @@ char	*strsep();
 
 /*
  * Actual vector of library search directories,
- * including `-L'ed and LD_LIBARAY_PATH spec'd ones.
+ * including `-L'ed and LD_LIBRARY_PATH spec'd ones.
  */
 char	 **search_dirs;
 int	n_search_dirs;
@@ -73,9 +71,14 @@ void
 add_search_dir(name)
 	char	*name;
 {
+	int n;
+
+	for (n = 0; n < n_search_dirs; n++)
+		if (strcmp(search_dirs[n], name) == 0)
+			return;
 	n_search_dirs++;
 	search_dirs = (char **)
-		xrealloc(search_dirs, n_search_dirs * sizeof(char *));
+		xrealloc(search_dirs, n_search_dirs * sizeof search_dirs[0]);
 	search_dirs[n_search_dirs - 1] = strdup(name);
 }
 
@@ -83,17 +86,16 @@ void
 add_search_path(path)
 char	*path;
 {
-	register char	*cp;
+	register char	*cp, *dup;
 
 	if (path == NULL)
 		return;
 
-	/* Add search directories from `paths' */
-	while ((cp = strsep(&path, ":")) != NULL) {
+	/* Add search directories from `path' */
+	path = dup = strdup(path);
+	while ((cp = strsep(&path, ":")) != NULL)
 		add_search_dir(cp);
-		if (path)
-			*(path-1) = ':';
-	}
+	free(dup);
 }
 
 void
diff --git a/libexec/rtld-aout/shlib.h b/libexec/rtld-aout/shlib.h
new file mode 100644
index 0000000..796d37e
--- /dev/null
+++ b/libexec/rtld-aout/shlib.h
@@ -0,0 +1,43 @@
+/*-
+ * Copyright (C) 1996
+ *	Peter Wemm.  All rights reserved.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ *-
+ * $Id$
+ */
+
+/*
+ * prototypes for shlib.c.  Big deal.
+ */
+
+extern char	**search_dirs;
+extern int	n_search_dirs;
+
+void	add_search_dir __P((char *));
+void	add_search_path __P((char *));
+void	std_search_path __P((void));
+int	getdewey __P((int[], char *));
+int	cmpndewey __P((int[], int, int[], int));
+char	*findshlib __P((char *, int *, int *, int));
+char	*find_lib_file __P((char *));
+char	*search_lib_dir __P((char *, char *, int *, int *, int));
diff --git a/libexec/rtld-aout/support.c b/libexec/rtld-aout/support.c
new file mode 100644
index 0000000..6fdf505
--- /dev/null
+++ b/libexec/rtld-aout/support.c
@@ -0,0 +1,86 @@
+/*
+ * Generic "support" routines to replace those obtained from libiberty for ld.
+ *
+ * I've collected these from random bits of (published) code I've written
+ * over the years, not that they are a big deal.  peter@freebsd.org
+ *-
+ * Copyright (C) 1996
+ *	Peter Wemm.  All rights reserved.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ *-
+ * $Id$
+ */
+#include <sys/types.h>
+#include <string.h>
+#include <stdlib.h>
+#include <err.h>
+
+#include "support.h"
+
+char *
+concat(s1, s2, s3)
+	const char *s1, *s2, *s3;
+{
+	int len = 1;
+	char *s;
+	if (s1)
+		len += strlen(s1);
+	if (s2)
+		len += strlen(s2);
+	if (s3)
+		len += strlen(s3);
+	s = malloc(len);
+	s[0] = '\0';
+	if (s1)
+		strcat(s, s1);
+	if (s2)
+		strcat(s, s2);
+	if (s3)
+		strcat(s, s3);
+	return s;
+}
+
+void *
+xmalloc(n)
+	size_t n;
+{
+	char *p = malloc(n);
+
+	if (p == NULL)
+		errx(1, "Could not allocate memory");
+
+	return p;
+}
+
+void *
+xrealloc(p, n)
+	void *p;
+	size_t n;
+{
+	p = realloc(p, n);
+
+	if (p == NULL)
+		errx(1, "Could not allocate memory");
+
+	return p;
+}
diff --git a/libexec/rtld-aout/support.h b/libexec/rtld-aout/support.h
new file mode 100644
index 0000000..5be1e31
--- /dev/null
+++ b/libexec/rtld-aout/support.h
@@ -0,0 +1,35 @@
+/*-
+ * Copyright (C) 1996
+ *	Peter Wemm.  All rights reserved.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ *-
+ * $Id$
+ */
+
+/*
+ * prototypes for support.c.  Big deal.
+ */
+
+void	*xmalloc __P((size_t));
+void	*xrealloc __P((void *, size_t));
+char	*concat __P((const char *, const char *, const char *));