SEO

An earlier version of this was posted before, but I think this latest
one actually works. It adds support for listing shared library
dependencies, so for example:

% ldd /usr/local/lib/libgtk.so.1.2
/usr/local/lib/libgtk.so.1.2:
Start End Type Open Ref GrpRef Name
0d312000 2d349000 rlib 0 1 0 /usr/lib/libc.so.34.2
0965d000 0965d000 rtld 0 1 0 /usr/libexec/ld.so
0fb9b000 2fb9f000 rlib 0 1 0 /usr/local/lib/libgmodule.so.1.2
0344c000 23453000 rlib 0 1 0 /usr/local/lib/libglib.so.1.2
0a958000 2a95c000 rlib 0 1 0 /usr/X11R6/lib/libXi.so.8.0
00f02000 20f06000 rlib 0 2 0 /usr/X11R6/lib/libXext.so.8.0
0a553000 2a59e000 rlib 0 3 0 /usr/X11R6/lib/libX11.so.8.1
09ae4000 29aeb000 rlib 0 1 0 /usr/lib/libm.so.2.0
0c07d000 2c159000 rlib 0 1 0 /usr/local/lib/libiconv.so.4.0
05d0c000 25d10000 rlib 0 1 0 /usr/local/lib/libintl.so.2.0

It doesn't execute constructors and destructors as well. I tested it
with this library but maybe there's a better way:
#include <stdio.h>
void __attribute__ ((constructor)) dl_init(void) {
printf("constructor!\n");
}
void __attribute__ ((destructor)) dl_fini(void) {
printf("destructor!\n");
}

Anyone else want to test this or poke holes in it?

Thanks,
Matt

Index: include/dlfcn.h
================================================== =================
RCS file: /cvs/src/include/dlfcn.h,v
retrieving revision 1.9
diff -u -r1.9 dlfcn.h
--- include/dlfcn.h 11 Aug 2004 19:14:56 -0000 1.9
+++ include/dlfcn.h 24 Aug 2006 22:56:47 -0000
@@ -64,6 +64,7 @@
#define RTLD_GLOBAL 0x100
#define RTLD_LOCAL 0x000
#define DL_LAZY RTLD_LAZY /* Compat */
+#define RTLD_TRACE 0x200

/*
* Special handle arguments for dlsym().
Index: libexec/ld.so/dlfcn.c
================================================== =================
RCS file: /cvs/src/libexec/ld.so/dlfcn.c,v
retrieving revision 1.73
diff -u -r1.73 dlfcn.c
--- libexec/ld.so/dlfcn.c 8 May 2006 20:34:36 -0000 1.73
+++ libexec/ld.so/dlfcn.c 24 Aug 2006 22:56:59 -0000
@@ -53,6 +53,9 @@
if (libname == NULL)
return RTLD_DEFAULT;

+ if ((flags & RTLD_TRACE) == RTLD_TRACE)
+ _dl_traceld = "true";
+
DL_DEB(("dlopen: loading: %s\n", libname));

_dl_thread_kern_stop();
@@ -95,6 +98,11 @@
} else {
int err;
DL_DEB(("tail %s\n", object->load_name ));
+ if (_dl_traceld) {
+ _dl_show_objects();
+ _dl_unload_shlib(object);
+ _dl_exit(0);
+ }
err = _dl_rtld(object);
if (err != 0) {
_dl_real_close(object);
@@ -365,13 +373,23 @@
objtypename = "rtld";
break;
case OBJTYPE_EXE:
- objtypename = "exe ";
+ if (_dl_debug)
+ objtypename = "exe ";
+ else {
+ object = object->next;
+ continue;
+ }
break;
case OBJTYPE_LIB:
objtypename = "rlib";
break;
case OBJTYPE_DLO:
- objtypename = "dlib";
+ if (_dl_debug)
+ objtypename = "dlib";
+ else {
+ object = object->next;
+ continue;
+ }
break;
default:
objtypename = "????";
Index: libexec/ld.so/ldd/ldd.c
================================================== =================
RCS file: /cvs/src/libexec/ld.so/ldd/ldd.c,v
retrieving revision 1.11
diff -u -r1.11 ldd.c
--- libexec/ld.so/ldd/ldd.c 10 Jul 2003 00:04:28 -0000 1.11
+++ libexec/ld.so/ldd/ldd.c 24 Aug 2006 22:56:59 -0000
@@ -31,10 +31,12 @@
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
+#include <dlfcn.h>

#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/wait.h>
+#include <sys/param.h>

int usage(void);
int doit(char *);
@@ -93,8 +95,9 @@
Elf_Ehdr ehdr;
Elf_Phdr *phdr;
int fd, i, size, status;
+ char buf[MAXPATHLEN];
+ void * dlhandle;

- printf("%s:\n", name);

if ((fd = open(name, O_RDONLY)) < 0) {
warn("%s", name);
@@ -114,6 +117,21 @@
return 1;
}

+ if (ehdr.e_type == ET_DYN) {
+ printf("%s:\n", name);
+ if (realpath(name, buf) == NULL) {
+ warn("realpath(%s)", name);
+ return 1;
+ }
+ dlhandle = dlopen(buf, RTLD_TRACE);
+ if (dlhandle == NULL) {
+ printf("%s\n", dlerror());
+ return 1;
+ }
+ close(fd);
+ return 0;
+ }
+
size = ehdr.e_phnum * sizeof(Elf_Phdr);
if ((phdr = malloc(size)) == NULL)
err(1, "malloc");
@@ -135,6 +153,7 @@
return 1;
}

+ printf("%s:\n", name);
fflush(stdout);
switch (fork()) {
case -1: