Incorporate John Polstra's sods.c display of the details about the

dynamic linking information in the executable.  It's quite extensive.
It's connected to ldd's (new) -v option.

4 files changed, 533 insertions, 4 deletions

diff --git a/usr.bin/ldd/Makefile b/usr.bin/ldd/Makefile
index 282a8fd..0335103 100644
--- a/usr.bin/ldd/Makefile
+++ b/usr.bin/ldd/Makefile
@@ -1,7 +1,7 @@
-#	$Id: Makefile,v 1.2 1993/11/09 04:19:24 paul Exp $
+#	$Id: Makefile,v 1.3 1993/12/16 21:51:27 nate Exp $
 
 PROG=	ldd
-SRCS=	ldd.c
+SRCS=	ldd.c sods.c
 BINDIR= /usr/bin
 
 .include <bsd.prog.mk>
diff --git a/usr.bin/ldd/ldd.1 b/usr.bin/ldd/ldd.1
index 8253470..1a09103 100644
--- a/usr.bin/ldd/ldd.1
+++ b/usr.bin/ldd/ldd.1
@@ -7,6 +7,7 @@
 .Sh SYNOPSIS
 .Nm ldd
 .Op Fl f Ar format
+.Op Fl v
 .Ar program ...
 .Sh DESCRIPTION
 .Nm ldd
@@ -25,6 +26,12 @@ and allows customization of
 output. See
 .Xr rtld 1
 for a list of recognised conversion characters.
+.Pp
+The
+.Fl v
+option displays an verbose listing of the dynamic linking headers
+encoded in the executable.  See the source code and include
+files for the definitive meaning of all the fields.
 .Sh SEE ALSO
 .Xr ld 1 ,
 .Xr ld.so 1 ,
@@ -34,3 +41,7 @@ A
 .Nm ldd
 utility first appeared in SunOS 4.0, it appeared in its current form
 in FreeBSD 1.1.
+.Pp
+The
+.Fl v
+support is based on code written by John Polstra <jdp@polstra.com>
diff --git a/usr.bin/ldd/ldd.c b/usr.bin/ldd/ldd.c
index 79a229b..841baf8 100644
--- a/usr.bin/ldd/ldd.c
+++ b/usr.bin/ldd/ldd.c
@@ -27,7 +27,7 @@
  * (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: ldd.c,v 1.5 1994/12/23 22:31:31 nate Exp $
+ *	$Id: ldd.c,v 1.6 1996/10/01 01:34:32 peter Exp $
  */
 
 #include <sys/types.h>
@@ -44,6 +44,9 @@
 #include <string.h>
 #include <unistd.h>
 
+extern void	dump_filename __P((const char *));
+extern int	error_count;
+
 void
 usage()
 {
@@ -61,9 +64,13 @@ char	*argv[];
 	char		*fmt1 = NULL, *fmt2 = NULL;
 	int		rval;
 	int		c;
+	int		vflag;
 
-	while ((c = getopt(argc, argv, "f:")) != EOF) {
+	while ((c = getopt(argc, argv, "vf:")) != EOF) {
 		switch (c) {
+		case 'v':
+			vflag++;
+			break;
 		case 'f':
 			if (fmt1) {
 				if (fmt2)
@@ -80,11 +87,20 @@ char	*argv[];
 	argc -= optind;
 	argv += optind;
 
+	if (vflag && fmt1)
+		errx(1, "-v may not be used with -f");
+
 	if (argc <= 0) {
 		usage();
 		/*NOTREACHED*/
 	}
 
+	if (vflag) {
+		for (c = 0; c < argc; c++)
+			dump_file(argv[c]);
+		exit(error_count == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
+	}
+
 	/* ld.so magic */
 	setenv("LD_TRACE_LOADED_OBJECTS", "", 1);
 	if (fmt1)
diff --git a/usr.bin/ldd/sods.c b/usr.bin/ldd/sods.c
new file mode 100644
index 0000000..4a9e904
--- /dev/null
+++ b/usr.bin/ldd/sods.c
@@ -0,0 +1,502 @@
+/*
+ * Copyright (C) 1996 John D. Polstra.  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 JOHN D. POLSTRA 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 JOHN D. POLSTRA 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 <assert.h>
+#include <ctype.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#include <a.out.h>
+#include <link.h>
+#include <stab.h>
+
+#ifndef N_SETA
+#define	N_SETA	0x14		/* Absolute set element symbol */
+#endif				/* This is input to LD, in a .o file.  */
+
+#ifndef N_SETT
+#define	N_SETT	0x16		/* Text set element symbol */
+#endif				/* This is input to LD, in a .o file.  */
+
+#ifndef N_SETD
+#define	N_SETD	0x18		/* Data set element symbol */
+#endif				/* This is input to LD, in a .o file. */
+
+#ifndef N_SETB
+#define	N_SETB	0x1A		/* Bss set element symbol */
+#endif				/* This is input to LD, in a .o file. */
+
+#ifndef N_SETV
+#define N_SETV	0x1C		/* Pointer to set vector in data area. */
+#endif				/* This is output from LD. */
+
+#ifdef STANDALONE
+static
+#endif
+void dump_file(const char *);
+
+static void dump_rels(const char *, const struct relocation_info *,
+    unsigned long, const char *(*)(unsigned long), unsigned char *);
+static void dump_segs();
+static void dump_sods();
+static void dump_sym(const struct nlist *);
+static void dump_syms();
+
+static void dump_rtrels();
+static void dump_rtsyms();
+
+static void error(const char *, ...);
+static const char *rtsym_name(unsigned long);
+static const char *sym_name(unsigned long);
+
+#ifdef STANDALONE
+static
+#endif
+int error_count;
+
+/*
+ * Variables ending in _base are pointers to things in our address space,
+ * i.e., in the file itself.
+ *
+ * Variables ending in _addr are adjusted according to where things would
+ * actually appear in memory if the file were loaded.
+ */
+static const char *file_base;
+static const char *text_base;
+static const char *data_base;
+static const struct relocation_info *rel_base;
+static const struct nlist *sym_base;
+static const char *str_base;
+
+static const struct relocation_info *rtrel_base;
+static const struct nzlist *rtsym_base;
+static const char *rtstr_base;
+
+static const struct exec *ex;
+static const struct _dynamic *dyn;
+static const struct section_dispatch_table *sdt;
+
+static const char *text_addr;
+static const char *data_addr;
+
+static unsigned long rel_count;
+static unsigned long sym_count;
+
+static unsigned long rtrel_count;
+static unsigned long rtsym_count;
+
+/* Dynamically allocated flags, 1 byte per symbol, to record whether each
+   symbol was referenced by a relocation entry. */
+static unsigned char *sym_used;
+static unsigned char *rtsym_used;
+
+static unsigned long origin;	/* What values are relocated relative to */
+
+#ifdef STANDALONE
+main(int argc, char *argv[])
+{
+    int i;
+
+    for(i = 1;  i < argc;  ++i)
+	dump_file(argv[i]);
+
+    return error_count == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+#endif
+
+#ifdef STANDALONE
+static
+#endif
+void
+dump_file(const char *fname)
+{
+    int fd;
+    struct stat sb;
+    caddr_t objbase;
+    long load_offset;
+
+    if(stat(fname, &sb) == -1) {
+	error("Cannot stat \"%s\"", fname);
+	return;
+    }
+
+    if((sb.st_mode & S_IFMT) != S_IFREG) {
+	error("\"%s\" is not a regular file", fname);
+	return;
+    }
+
+    if((fd = open(fname, O_RDONLY, 0)) == -1) {
+	error("Cannot open \"%s\"", fname);
+	return;
+    }
+
+    objbase = mmap(0, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);
+    if(objbase == (caddr_t) -1) {
+	error("Cannot mmap \"%s\"", fname);
+	close(fd);
+	return;
+    }
+
+    close(fd);
+
+    file_base = (const char *) objbase;	/* Makes address arithmetic easier */
+
+    ex = (const struct exec *) file_base;
+
+    printf("%s: a_midmag = 0x%lx\n", fname, ex->a_midmag);
+    printf("  magic = 0x%x = 0%o, netmagic = 0x%x = 0%o\n",
+	N_GETMAGIC(*ex), N_GETMAGIC(*ex),
+	N_GETMAGIC_NET(*ex), N_GETMAGIC_NET(*ex));
+
+    if(N_BADMAG(*ex)) {
+	error("%s: Bad magic number", fname);
+	munmap(objbase, sb.st_size);
+	return;
+    }
+
+    printf("  a_text   = 0x%lx\n", ex->a_text);
+    printf("  a_data   = 0x%lx\n", ex->a_data);
+    printf("  a_bss    = 0x%lx\n", ex->a_bss);
+    printf("  a_syms   = 0x%lx\n", ex->a_syms);
+    printf("  a_entry  = 0x%lx\n", ex->a_entry);
+    printf("  a_trsize = 0x%lx\n", ex->a_trsize);
+    printf("  a_drsize = 0x%lx\n", ex->a_drsize);
+
+    load_offset = N_TXTADDR(*ex) - N_TXTOFF(*ex);
+
+    text_base = file_base + N_TXTOFF(*ex);
+    data_base = file_base + N_DATOFF(*ex);
+    rel_base = (const struct relocation_info *) (file_base + N_RELOFF(*ex));
+    sym_base = (const struct nlist *) (file_base + N_SYMOFF(*ex));
+    str_base = file_base + N_STROFF(*ex);
+
+    rel_count = (ex->a_trsize + ex->a_drsize) / sizeof rel_base[0];
+    assert(rel_count * sizeof rel_base[0] == ex->a_trsize + ex->a_drsize);
+    sym_count = ex->a_syms / sizeof sym_base[0];
+    assert(sym_count * sizeof sym_base[0] == ex->a_syms);
+
+    if(sym_count != 0) {
+	sym_used = (unsigned char *) calloc(sym_count, sizeof(unsigned char));
+	assert(sym_used != NULL);
+    }
+
+    printf("  Entry = 0x%x, load offset = 0x%lx\n",
+	ex->a_entry, load_offset);
+    printf("  Text offset = %lx, address = %lx\n", N_TXTOFF(*ex),
+	N_TXTADDR(*ex));
+    printf("  Data offset = %lx, address = %lx\n", N_DATOFF(*ex),
+	N_DATADDR(*ex));
+
+    /*
+     * DEBUG
+     *
+     * In an executable program file, everything is relocated relative to
+     * the assumed run-time load address, i.e., N_TXTADDR(*ex), i.e., 0x1000.
+     *
+     * In a shared library file, everything is relocated relative to the
+     * start of the file, i.e., N_TXTOFF(*ex), i.e., 0.
+     *
+     * The way to tell the difference is by looking at ex->a_entry.   If it
+     * is >= 0x1000, then we have an executable program.  Otherwise, we
+     * have a shared library.
+     *
+     * When a program is executed, the entire file is mapped into memory,
+     * including the a.out header and so forth.  But it is not mapped at
+     * address 0; rather it is mapped at address 0x1000.  The first page
+     * of the user's address space is left unmapped in order to catch null
+     * pointer dereferences.
+     *
+     * In this program, when we map in an executable program, we have to
+     * simulate the empty page by decrementing our assumed base address by
+     * a pagesize.
+     */
+
+    text_addr = text_base;
+    data_addr = data_base;
+    origin = 0;
+
+    if(ex->a_entry >= load_offset) {	/* Executable, not a shared library */
+	/*
+	 * The fields in the object have already been relocated on the
+	 * assumption that the object will be loaded at N_TXTADDR(*ex).
+	 * We have to compensate for that.
+	 */
+	text_addr -= load_offset;
+	data_addr -= load_offset;
+	origin = load_offset;
+	printf("  Program, origin = %lx\n", origin);
+    } else
+	printf("  Library, origin = %lx\n", origin);
+
+    if(N_GETFLAG(*ex) & EX_DYNAMIC) {
+	dyn = (const struct _dynamic *) data_base;
+	sdt = (const struct section_dispatch_table *)
+	    (text_addr + (unsigned long) dyn->d_un.d_sdt);
+
+	rtrel_base =
+	    (const struct relocation_info *) (text_addr + sdt->sdt_rel);
+	rtrel_count = (sdt->sdt_hash - sdt->sdt_rel) / sizeof rtrel_base[0];
+	assert(rtrel_count * sizeof rtrel_base[0] ==
+	    sdt->sdt_hash - sdt->sdt_rel);
+
+	rtsym_base = (const struct nzlist *) (text_addr + sdt->sdt_nzlist);
+	rtsym_count = (sdt->sdt_strings - sdt->sdt_nzlist) /
+	    sizeof rtsym_base[0];
+	assert(rtsym_count * sizeof rtsym_base[0] ==
+	    sdt->sdt_strings - sdt->sdt_nzlist);
+
+	if(rtsym_count != 0) {
+	    rtsym_used = (unsigned char *) calloc(rtsym_count,
+		sizeof(unsigned char));
+	    assert(rtsym_used != NULL);
+	}
+
+	rtstr_base = text_addr + sdt->sdt_strings;
+    }
+
+    dump_segs();
+    dump_sods();
+    dump_rels("Relocations", rel_base, rel_count, sym_name, sym_used);
+    dump_syms();
+
+    dump_rels("Run-time relocations", rtrel_base, rtrel_count, rtsym_name,
+	rtsym_used);
+    dump_rtsyms();
+
+    if(rtsym_used != NULL) {
+	free(rtsym_used);
+	rtsym_used = NULL;
+    }
+    if(sym_used != NULL) {
+	free(sym_used);
+	sym_used = NULL;
+    }
+    munmap(objbase, sb.st_size);
+}
+
+static void
+dump_rels(const char *label, const struct relocation_info *base,
+    unsigned long count, const char *(*name)(unsigned long),
+    unsigned char *sym_used_flags)
+{
+    unsigned long i;
+
+    printf("  %s:\n", label);
+    for(i = 0;  i < count;  ++i) {
+	const struct relocation_info *r = &base[i];
+
+	printf("    %6lu %8x/%u %c%c%c%c%c%c", i,
+	    r->r_address, 1u << r->r_length,
+	    r->r_extern   ? 'e' : '-',
+	    r->r_jmptable ? 'j' : '-',
+	    r->r_relative ? 'r' : '-',
+	    r->r_baserel  ? 'b' : '-',
+	    r->r_pcrel    ? 'p' : '-',
+	    r->r_copy     ? 'c' : '-');
+
+	if(r->r_extern || r->r_baserel || r->r_jmptable || r->r_copy) {
+	    printf(" %4u %s", r->r_symbolnum, name(r->r_symbolnum));
+	    sym_used_flags[r->r_symbolnum] = 1;
+	}
+
+	printf("\n");
+    }
+}
+
+static void
+dump_rtsyms()
+{
+    unsigned long i;
+
+    printf("  Run-time symbols:\n");
+    for(i = 0;  i < rtsym_count;  ++i) {
+	printf("    %6lu%c ", i, rtsym_used[i] ? '*' : ' ');
+	dump_sym(&rtsym_base[i].nlist);
+	printf("/%-5ld %s\n", rtsym_base[i].nz_size, rtsym_name(i));
+    }
+}
+
+static void
+dump_segs()
+{
+    printf("  Text segment starts at address %lx\n", origin + N_TXTOFF(*ex));
+    if(N_GETFLAG(*ex) & EX_DYNAMIC) {
+	printf("    rel starts at %lx\n", sdt->sdt_rel);
+	printf("    hash starts at %lx\n", sdt->sdt_hash);
+	printf("    nzlist starts at %lx\n", sdt->sdt_nzlist);
+	printf("    strings starts at %lx\n", sdt->sdt_strings);
+    }
+
+    printf("  Data segment starts at address %lx\n", origin + N_DATOFF(*ex));
+    if(N_GETFLAG(*ex) & EX_DYNAMIC) {
+	printf("    _dynamic starts at %lx\n", origin + N_DATOFF(*ex));
+	printf("    so_debug starts at %lx\n", (unsigned long) dyn->d_debug);
+	printf("    sdt starts at %lx\n", (unsigned long) dyn->d_un.d_sdt);
+	printf("    got starts at %lx\n", sdt->sdt_got);
+	printf("    plt starts at %lx\n", sdt->sdt_plt);
+	printf("    rest of stuff starts at %lx\n",
+	    sdt->sdt_plt + sdt->sdt_plt_sz);
+    }
+}
+
+static void
+dump_sods()
+{
+    long sod_offset;
+    long paths_offset;
+
+    if(dyn == NULL)		/* Not a shared object */
+	return;
+
+    sod_offset = sdt->sdt_sods;
+    printf("  Shared object dependencies:\n");
+    while(sod_offset != 0) {
+	const struct sod *sodp = (const struct sod *) (text_addr + sod_offset);
+	const char *name = (const char *) (text_addr + sodp->sod_name);
+
+	printf("    -l%-16s version %d.%d\n", name, sodp->sod_major,
+	    sodp->sod_minor);
+	sod_offset = sodp->sod_next;
+    }
+    paths_offset = sdt->sdt_paths;
+    printf("  Shared object additional paths:\n");
+    if (paths_offset != 0) {
+	char *path = (char *)(text_addr + paths_offset);
+	printf("    %s\n", path);
+    } else {
+	printf("    NULL\n");
+    }
+}
+
+static void
+dump_sym(const struct nlist *np)
+{
+    char type[8];
+    char *p;
+
+    switch(np->n_type & ~N_EXT) {
+    case N_UNDF:	strcpy(type, "undf");  break;
+    case N_ABS:		strcpy(type, "abs");  break;
+    case N_TEXT:	strcpy(type, "text");  break;
+    case N_DATA:	strcpy(type, "data");  break;
+    case N_BSS:		strcpy(type, "bss");  break;
+    case N_INDR:	strcpy(type, "indr");  break;
+    case N_SIZE:	strcpy(type, "size");  break;
+    case N_COMM:	strcpy(type, "comm");  break;
+    case N_SETA:	strcpy(type, "seta");  break;
+    case N_SETT:	strcpy(type, "sett");  break;
+    case N_SETD:	strcpy(type, "setd");  break;
+    case N_SETB:	strcpy(type, "setb");  break;
+    case N_SETV:	strcpy(type, "setv");  break;
+    case N_FN:		strcpy(type, np->n_type&N_EXT ? "fn" : "warn");  break;
+    case N_GSYM:	strcpy(type, "gsym");  break;
+    case N_FNAME:	strcpy(type, "fname");  break;
+    case N_FUN:		strcpy(type, "fun");  break;
+    case N_STSYM:	strcpy(type, "stsym");  break;
+    case N_LCSYM:	strcpy(type, "lcsym");  break;
+    case N_MAIN:	strcpy(type, "main");  break;
+    case N_PC:		strcpy(type, "pc");  break;
+    case N_RSYM:	strcpy(type, "rsym");  break;
+    case N_SLINE:	strcpy(type, "sline");  break;
+    case N_DSLINE:	strcpy(type, "dsline");  break;
+    case N_BSLINE:	strcpy(type, "bsline");  break;
+    case N_SSYM:	strcpy(type, "ssym");  break;
+    case N_SO:		strcpy(type, "so");  break;
+    case N_LSYM:	strcpy(type, "lsym");  break;
+    case N_BINCL:	strcpy(type, "bincl");  break;
+    case N_SOL:		strcpy(type, "sol");  break;
+    case N_PSYM:	strcpy(type, "psym");  break;
+    case N_EINCL:	strcpy(type, "eincl");  break;
+    case N_ENTRY:	strcpy(type, "entry");  break;
+    case N_LBRAC:	strcpy(type, "lbrac");  break;
+    case N_EXCL:	strcpy(type, "excl");  break;
+    case N_RBRAC:	strcpy(type, "rbrac");  break;
+    case N_BCOMM:	strcpy(type, "bcomm");  break;
+    case N_ECOMM:	strcpy(type, "ecomm");  break;
+    case N_ECOML:	strcpy(type, "ecoml");  break;
+    case N_LENG:	strcpy(type, "leng");  break;
+    default:		sprintf(type, "0x%02x", np->n_type);
+    }
+
+    if(np->n_type & N_EXT && type[0] != '0')
+	for(p = type;  *p != '\0';  ++p)
+	    *p = toupper(*p);
+
+    printf("%-5s %8lx", type, np->n_value);
+}
+
+static void
+dump_syms()
+{
+    unsigned long i;
+
+    printf("  Symbols:\n");
+    for(i = 0;  i < sym_count;  ++i) {
+	printf("    %6lu%c ", i, sym_used[i] ? '*' : ' ');
+	dump_sym(&sym_base[i]);
+	printf(" %s\n", sym_name(i));
+    }
+}
+
+static void
+error(const char *format, ...)
+{
+    va_list ap;
+
+    va_start(ap, format);
+    vfprintf(stderr, format, ap);
+    va_end(ap);
+    putc('\n', stderr);
+
+    ++error_count;
+}
+
+static const char *
+rtsym_name(unsigned long n)
+{
+    assert(n < rtsym_count);
+    if(rtsym_base[n].nz_strx == 0)
+	return "";
+    return rtstr_base + rtsym_base[n].nz_strx;
+}
+
+static const char *
+sym_name(unsigned long n)
+{
+    assert(n < sym_count);
+    if(sym_base[n].n_un.n_strx == 0)
+	return "";
+    return str_base + sym_base[n].n_un.n_strx;
+}