PATCH: --with-sysroot for GDB

PATCH: --with-sysroot for GDB

[Daniel Jacobowitz]

[Copied to Dan K. 'cause I know he'll like it :)]

Both binutils and GCC now support (although GCC's support isn't quite
finished yet, working on it...) a mechanism called "sysroot" for
handling cross environments.  The basic principal is that anything that
would normally access the "target" filesystem does so just as if it
were a native debugger running on $target, but prefixes all paths with
the value of the sysroot prefix.  We use $target/usr/include,
$target/etc/ld.so.conf, $target/lib, et cetera.  This is really great
for people using, for instance, gdbserver to debug a remote GNU/Linux
installation.  I bet the QNX people could use this, too.

Free bonus: as long as the sysroot is actually within $exec_prefix
(otherwise the relocation functions don't work right), it will move
along with the binary.  You can pick up the whole tree, drop it
somewhere else, and keep using it; no rebuild, no reconfigure.

Here's a patch to do the same thing in GDB.  Right now all it sets is
solib-absolute-prefix; that's because I can't think of anything else it
should affect, but if you have any ideas speak right up.

It also documents solib-absolute-prefix and solib-search-path, which
have been conspicuously missing from the manual for some time.

Thoughts?  I'll look to apply this in a couple of days if no one
objects to the way I implemented it.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

2003-01-09  Daniel Jacobowitz  <drow@mvista.com>

	* Makefile.in (TARGET_SYSTEM_ROOT, TARGET_SYSTEM_ROOT_DEFINE): New
	variables.
	(main.o): Custom rule which uses $(TARGET_SYSTEM_ROOT_DEFINE).
	* configure.in: Add --with-sysroot.
	* main.c (gdb_sysroot): New variable.
	(captured_main): Initialize gdb_sysroot.
	* defs.h (gdb_sysroot): New extern declaration.

2003-01-09  Daniel Jacobowitz  <drow@mvista.com>

	* gdb.texinfo (Files): Document solib-absolute-prefix and
	solib-search-path.

Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.310
diff -u -p -r1.310 Makefile.in
--- Makefile.in	6 Jan 2003 20:45:30 -0000	1.310
+++ Makefile.in	9 Jan 2003 17:29:16 -0000
@@ -136,6 +136,10 @@ INTL_CFLAGS = -I$(INTL_DIR) -I$(INTL_SRC
 # Where is the ICONV library?  This can be empty if libc has iconv.
 LIBICONV = @LIBICONV@
 
+# Did the user give us a --with-sysroot option?
+TARGET_SYSTEM_ROOT = @TARGET_SYSTEM_ROOT@
+TARGET_SYSTEM_ROOT_DEFINE = @TARGET_SYSTEM_ROOT_DEFINE@
+
 #
 # CLI sub directory definitons
 #
@@ -1402,6 +1406,11 @@ hpux-thread.o: $(srcdir)/hpux-thread.c
 	$(CC) -c $(INTERNAL_CFLAGS) -I$(srcdir)/osf-share \
 		-I$(srcdir)/osf-share/HP800 -I/usr/include/dce \
 		$(srcdir)/hpux-thread.c
+
+# main.o needs an explicit build rule to get TARGET_SYSTEM_ROOT and BINDIR.
+main.o: main.c
+	$(CC) -c $(INTERNAL_CFLAGS) $(TARGET_SYSTEM_ROOT_DEFINE) \
+		-DBINDIR=\"$(bindir)\" $(srcdir)/main.c
 
 # FIXME: Procfs.o gets -Wformat errors because things like pid_t don't
 # match output format strings.
Index: configure.in
===================================================================
RCS file: /cvs/src/src/gdb/configure.in,v
retrieving revision 1.116
diff -u -p -r1.116 configure.in
--- configure.in	4 Jan 2003 23:47:12 -0000	1.116
+++ configure.in	9 Jan 2003 17:29:18 -0000
@@ -851,6 +851,38 @@ fi
 
 dnl Handle optional features that can be enabled.
 
+AC_ARG_WITH(sysroot,
+[  --with-sysroot[=DIR] Search for usr/lib et al within DIR.],
+[
+ case ${with_sysroot} in
+ yes) AC_ERROR(with-sysroot must specify path) ;;
+ *) TARGET_SYSTEM_ROOT=$with_sysroot ;;
+ esac
+
+ TARGET_SYSTEM_ROOT_DEFINE='-DTARGET_SYSTEM_ROOT=\"$(TARGET_SYSTEM_ROOT)\"'
+
+ if test "x$exec_prefix" = xNONE; then
+  if test "x$prefix" = xNONE; then
+   test_prefix=/usr/local
+  else
+   test_prefix=$prefix
+  fi
+ else
+  test_prefix=$exec_prefix
+ fi
+ case ${TARGET_SYSTEM_ROOT} in
+ ${test_prefix}*)
+   t="$TARGET_SYSTEM_ROOT_DEFINE -DTARGET_SYSTEM_ROOT_RELOCATABLE"
+   TARGET_SYSTEM_ROOT_DEFINE="$t"
+   ;;
+ esac
+], [
+ TARGET_SYSTEM_ROOT=
+ TARGET_SYSTEM_ROOT_DEFINE='-DTARGET_SYSTEM_ROOT=\"\"'
+])
+AC_SUBST(TARGET_SYSTEM_ROOT)
+AC_SUBST(TARGET_SYSTEM_ROOT_DEFINE)
+
 # NOTE: Don't add -Wall or -Wunused, they both include
 # -Wunused-parameter which reports bogus warnings.
 # NOTE: If you add to this list, remember to update
Index: defs.h
===================================================================
RCS file: /cvs/src/src/gdb/defs.h,v
retrieving revision 1.107
diff -u -p -r1.107 defs.h
--- defs.h	6 Jan 2003 18:49:08 -0000	1.107
+++ defs.h	9 Jan 2003 17:29:18 -0000
@@ -169,6 +169,9 @@ extern int xdb_commands;
 /* enable dbx commands if set */
 extern int dbx_commands;
 
+/* System root path, used to find libraries etc.  */
+extern char *gdb_sysroot;
+
 extern int quit_flag;
 extern int immediate_quit;
 extern int sevenbit_strings;
Index: main.c
===================================================================
RCS file: /cvs/src/src/gdb/main.c,v
retrieving revision 1.20
diff -u -p -r1.20 main.c
--- main.c	26 Sep 2002 17:46:04 -0000	1.20
+++ main.c	9 Jan 2003 17:29:18 -0000
@@ -65,6 +65,9 @@ int xdb_commands = 0;
 /* Whether dbx commands will be handled */
 int dbx_commands = 0;
 
+/* System root path, used to find libraries etc.  */
+char *gdb_sysroot = 0;
+
 struct ui_file *gdb_stdout;
 struct ui_file *gdb_stderr;
 struct ui_file *gdb_stdlog;
@@ -200,6 +203,29 @@ captured_main (void *data)
 
   /* initialize error() */
   error_init ();
+
+  /* Set the sysroot path.  */
+#ifdef TARGET_SYSTEM_ROOT_RELOCATABLE
+  gdb_sysroot = make_relative_prefix (argv[0], BINDIR, TARGET_SYSTEM_ROOT);
+  if (gdb_sysroot)
+    {
+      struct stat s;
+      int res = stat (gdb_sysroot, &s) == 0 && S_ISDIR (s.st_mode);
+      if (!res)
+	{
+	  free (gdb_sysroot);
+	  gdb_sysroot = TARGET_SYSTEM_ROOT;
+	}
+    }
+  else
+    gdb_sysroot = TARGET_SYSTEM_ROOT;
+#else
+#if defined (TARGET_SYSTEM_ROOT)
+  gdb_sysroot = TARGET_SYSTEM_ROOT;
+#else
+  gdb_sysroot = "";
+#endif
+#endif
 
   /* Parse arguments and options.  */
   {
Index: solib.c
===================================================================
RCS file: /cvs/src/src/gdb/solib.c,v
retrieving revision 1.51
diff -u -p -r1.51 solib.c
--- solib.c	9 Dec 2002 00:59:26 -0000	1.51
+++ solib.c	9 Jan 2003 17:29:19 -0000
@@ -875,6 +875,10 @@ For other (relative) files, you can add 
   add_show_from_set (c, &showlist);
   set_cmd_completer (c, filename_completer);
 
+  /* Set the default value of "solib-absolute-prefix" from the sysroot, if
+     one is set.  */
+  solib_absolute_prefix = xstrdup (gdb_sysroot);
+
   c = add_set_cmd ("solib-search-path", class_support, var_string,
 		   (char *) &solib_search_path,
 		   "Set the search path for loading non-absolute shared library symbol files.\n\
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.136
diff -u -p -r1.136 gdb.texinfo
--- doc/gdb.texinfo	5 Jan 2003 04:34:39 -0000	1.136
+++ doc/gdb.texinfo	9 Jan 2003 17:29:23 -0000
@@ -9719,6 +9719,49 @@ Mb).
 Display the current autoloading size threshold, in megabytes.
 @end table
 
+Shared libraries are also supported in many cross or remote debugging
+configurations.  A copy of the target's libraries need to be present on the
+host system; they need to be the same as the target libraries, although the
+copies on the target can be stripped as long as the copies on the host are
+not.
+
+You need to tell @value{GDBN} where the target libraries are, so that it can
+load the correct copies---otherwise, it may try to load the host's libraries.
+@value{GDBN} has two variables to specify the search directories for target
+libraries.
+
+@table @code
+@kindex set solib-absolute-prefix
+@item set solib-absolute-prefix @var{path}
+If this variable is set, @var{path} will be used as a prefix for any
+absolute shared library paths; many runtime loaders store the absolute
+paths to the shared library in the target program's memory.  If you use
+@samp{solib-absolute-prefix} to find shared libraries, they need to be laid
+out in the same way that they are on the target, with e.g.@: a
+@file{/usr/lib} hierarchy under @var{path}.
+
+You can set the default value of @samp{solib-absolute-prefix} by using the
+configure-time @samp{--with-sysroot} option.
+
+@kindex show solib-absolute-prefix
+@item show solib-absolute-prefix
+Display the current shared library prefix.
+
+@kindex set solib-search-path
+@item set solib-search-path @var{path}
+If this variable is set, @var{path} is a colon-separated list of directories
+to search for shared libraries.  @samp{solib-search-path} is used after
+@samp{solib-absolute-prefix} fails to locate the library, or if the path to
+the library is relative instead of absolute.  If you want to use
+@samp{solib-search-path} instead of @samp{solib-absolute-prefix}, be sure to
+set @samp{solib-absolute-prefix} to a nonexistant directory to prevent
+@value{GDBN} from finding your host's libraries.
+
+@kindex show solib-search-path
+@item show solib-search-path
+Display the current shared library search path.
+@end table
+
 @node Symbol Errors
 @section Errors reading symbol files
 

Re: PATCH: --with-sysroot for GDB

[Kevin Buettner]

On Jan 9, 12:38pm, Daniel Jacobowitz wrote:

> Thoughts?  I'll look to apply this in a couple of days if no one
> objects to the way I implemented it.
> 
> 
> 2003-01-09  Daniel Jacobowitz  <drow@mvista.com>
> 
> 	* Makefile.in (TARGET_SYSTEM_ROOT, TARGET_SYSTEM_ROOT_DEFINE): New
> 	variables.
> 	(main.o): Custom rule which uses $(TARGET_SYSTEM_ROOT_DEFINE).
> 	* configure.in: Add --with-sysroot.
> 	* main.c (gdb_sysroot): New variable.
> 	(captured_main): Initialize gdb_sysroot.
> 	* defs.h (gdb_sysroot): New extern declaration.

You missed a ChangeLog entry for solib.c, but I've looked over that part
of the patch and it looks good.  (But do write a ChangeLog entry for it.)

Anyway, thanks -- something like this has been needed for a long time now.

Kevin

Re: PATCH: --with-sysroot for GDB

[Daniel Jacobowitz]

On Thu, Jan 09, 2003 at 11:37:00AM -0700, Kevin Buettner wrote:
> On Jan 9, 12:38pm, Daniel Jacobowitz wrote:
> 
> > Thoughts?  I'll look to apply this in a couple of days if no one
> > objects to the way I implemented it.
> > 
> > 
> > 2003-01-09  Daniel Jacobowitz  <drow@mvista.com>
> > 
> > 	* Makefile.in (TARGET_SYSTEM_ROOT, TARGET_SYSTEM_ROOT_DEFINE): New
> > 	variables.
> > 	(main.o): Custom rule which uses $(TARGET_SYSTEM_ROOT_DEFINE).
> > 	* configure.in: Add --with-sysroot.
> > 	* main.c (gdb_sysroot): New variable.
> > 	(captured_main): Initialize gdb_sysroot.
> > 	* defs.h (gdb_sysroot): New extern declaration.
> 
> You missed a ChangeLog entry for solib.c, but I've looked over that part
> of the patch and it looks good.  (But do write a ChangeLog entry for it.)

Oops, thanks for spotting that!  Will fix before I check it in.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: PATCH: --with-sysroot for GDB

[Elena Zannoni]

Daniel Jacobowitz writes:
 > [Copied to Dan K. 'cause I know he'll like it :)]
 > 
 > Both binutils and GCC now support (although GCC's support isn't quite
 > finished yet, working on it...) a mechanism called "sysroot" for
 > handling cross environments.  The basic principal is that anything that
 > would normally access the "target" filesystem does so just as if it
 > were a native debugger running on $target, but prefixes all paths with
 > the value of the sysroot prefix.  We use $target/usr/include,
 > $target/etc/ld.so.conf, $target/lib, et cetera.  This is really great
 > for people using, for instance, gdbserver to debug a remote GNU/Linux
 > installation.  I bet the QNX people could use this, too.
 > 
 > Free bonus: as long as the sysroot is actually within $exec_prefix
 > (otherwise the relocation functions don't work right), it will move
 > along with the binary.  You can pick up the whole tree, drop it
 > somewhere else, and keep using it; no rebuild, no reconfigure.
 > 
 > Here's a patch to do the same thing in GDB.  Right now all it sets is
 > solib-absolute-prefix; that's because I can't think of anything else it
 > should affect, but if you have any ideas speak right up.
 > 
 > It also documents solib-absolute-prefix and solib-search-path, which
 > have been conspicuously missing from the manual for some time.
 > 
 > Thoughts?  I'll look to apply this in a couple of days if no one
 > objects to the way I implemented it.

main.c ok, except for.... see below:

 > 
 > -- 
 > Daniel Jacobowitz
 > MontaVista Software                         Debian GNU/Linux Developer
 > 
 > 2003-01-09  Daniel Jacobowitz  <drow@mvista.com>
 > 
 > 	* Makefile.in (TARGET_SYSTEM_ROOT, TARGET_SYSTEM_ROOT_DEFINE): New
 > 	variables.
 > 	(main.o): Custom rule which uses $(TARGET_SYSTEM_ROOT_DEFINE).
 > 	* configure.in: Add --with-sysroot.
 > 	* main.c (gdb_sysroot): New variable.
 > 	(captured_main): Initialize gdb_sysroot.
 > 	* defs.h (gdb_sysroot): New extern declaration.
 > 
 > 2003-01-09  Daniel Jacobowitz  <drow@mvista.com>
 > 
 > 	* gdb.texinfo (Files): Document solib-absolute-prefix and
 > 	solib-search-path.
 > 
 > Index: Makefile.in
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/Makefile.in,v
 > retrieving revision 1.310
 > diff -u -p -r1.310 Makefile.in
 > --- Makefile.in	6 Jan 2003 20:45:30 -0000	1.310
 > +++ Makefile.in	9 Jan 2003 17:29:16 -0000
 > @@ -136,6 +136,10 @@ INTL_CFLAGS = -I$(INTL_DIR) -I$(INTL_SRC
 >  # Where is the ICONV library?  This can be empty if libc has iconv.
 >  LIBICONV = @LIBICONV@
 >  
 > +# Did the user give us a --with-sysroot option?
 > +TARGET_SYSTEM_ROOT = @TARGET_SYSTEM_ROOT@
 > +TARGET_SYSTEM_ROOT_DEFINE = @TARGET_SYSTEM_ROOT_DEFINE@
 > +
 >  #
 >  # CLI sub directory definitons
 >  #
 > @@ -1402,6 +1406,11 @@ hpux-thread.o: $(srcdir)/hpux-thread.c
 >  	$(CC) -c $(INTERNAL_CFLAGS) -I$(srcdir)/osf-share \
 >  		-I$(srcdir)/osf-share/HP800 -I/usr/include/dce \
 >  		$(srcdir)/hpux-thread.c
 > +
 > +# main.o needs an explicit build rule to get TARGET_SYSTEM_ROOT and BINDIR.
 > +main.o: main.c
 > +	$(CC) -c $(INTERNAL_CFLAGS) $(TARGET_SYSTEM_ROOT_DEFINE) \
 > +		-DBINDIR=\"$(bindir)\" $(srcdir)/main.c
 >  
 >  # FIXME: Procfs.o gets -Wformat errors because things like pid_t don't
 >  # match output format strings.
 > Index: configure.in
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/configure.in,v
 > retrieving revision 1.116
 > diff -u -p -r1.116 configure.in
 > --- configure.in	4 Jan 2003 23:47:12 -0000	1.116
 > +++ configure.in	9 Jan 2003 17:29:18 -0000
 > @@ -851,6 +851,38 @@ fi
 >  
 >  dnl Handle optional features that can be enabled.
 >  
 > +AC_ARG_WITH(sysroot,
 > +[  --with-sysroot[=DIR] Search for usr/lib et al within DIR.],
 > +[
 > + case ${with_sysroot} in
 > + yes) AC_ERROR(with-sysroot must specify path) ;;
 > + *) TARGET_SYSTEM_ROOT=$with_sysroot ;;
 > + esac
 > +
 > + TARGET_SYSTEM_ROOT_DEFINE='-DTARGET_SYSTEM_ROOT=\"$(TARGET_SYSTEM_ROOT)\"'
 > +
 > + if test "x$exec_prefix" = xNONE; then
 > +  if test "x$prefix" = xNONE; then
 > +   test_prefix=/usr/local
 > +  else
 > +   test_prefix=$prefix
 > +  fi
 > + else
 > +  test_prefix=$exec_prefix
 > + fi
 > + case ${TARGET_SYSTEM_ROOT} in
 > + ${test_prefix}*)
 > +   t="$TARGET_SYSTEM_ROOT_DEFINE -DTARGET_SYSTEM_ROOT_RELOCATABLE"
 > +   TARGET_SYSTEM_ROOT_DEFINE="$t"
 > +   ;;
 > + esac
 > +], [
 > + TARGET_SYSTEM_ROOT=
 > + TARGET_SYSTEM_ROOT_DEFINE='-DTARGET_SYSTEM_ROOT=\"\"'
 > +])
 > +AC_SUBST(TARGET_SYSTEM_ROOT)
 > +AC_SUBST(TARGET_SYSTEM_ROOT_DEFINE)
 > +
 >  # NOTE: Don't add -Wall or -Wunused, they both include
 >  # -Wunused-parameter which reports bogus warnings.
 >  # NOTE: If you add to this list, remember to update
 > Index: defs.h
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/defs.h,v
 > retrieving revision 1.107
 > diff -u -p -r1.107 defs.h
 > --- defs.h	6 Jan 2003 18:49:08 -0000	1.107
 > +++ defs.h	9 Jan 2003 17:29:18 -0000
 > @@ -169,6 +169,9 @@ extern int xdb_commands;
 >  /* enable dbx commands if set */
 >  extern int dbx_commands;
 >  
 > +/* System root path, used to find libraries etc.  */
 > +extern char *gdb_sysroot;
 > +
 >  extern int quit_flag;
 >  extern int immediate_quit;
 >  extern int sevenbit_strings;
 > Index: main.c
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/main.c,v
 > retrieving revision 1.20
 > diff -u -p -r1.20 main.c
 > --- main.c	26 Sep 2002 17:46:04 -0000	1.20
 > +++ main.c	9 Jan 2003 17:29:18 -0000
 > @@ -65,6 +65,9 @@ int xdb_commands = 0;
 >  /* Whether dbx commands will be handled */
 >  int dbx_commands = 0;
 >  
 > +/* System root path, used to find libraries etc.  */
 > +char *gdb_sysroot = 0;
 > +
 >  struct ui_file *gdb_stdout;
 >  struct ui_file *gdb_stderr;
 >  struct ui_file *gdb_stdlog;
 > @@ -200,6 +203,29 @@ captured_main (void *data)
 >  
 >    /* initialize error() */
 >    error_init ();
 > +
 > +  /* Set the sysroot path.  */
 > +#ifdef TARGET_SYSTEM_ROOT_RELOCATABLE
 > +  gdb_sysroot = make_relative_prefix (argv[0], BINDIR, TARGET_SYSTEM_ROOT);
 > +  if (gdb_sysroot)
 > +    {
 > +      struct stat s;
 > +      int res = stat (gdb_sysroot, &s) == 0 && S_ISDIR (s.st_mode);

please split this statement into an if + assignment.

Re: PATCH: --with-sysroot for GDB

[Daniel Jacobowitz]

On Thu, Jan 09, 2003 at 12:38:10PM -0500, Daniel Jacobowitz wrote:
> [Copied to Dan K. 'cause I know he'll like it :)]
> 
> Both binutils and GCC now support (although GCC's support isn't quite
> finished yet, working on it...) a mechanism called "sysroot" for
> handling cross environments.  The basic principal is that anything that
> would normally access the "target" filesystem does so just as if it
> were a native debugger running on $target, but prefixes all paths with
> the value of the sysroot prefix.  We use $target/usr/include,
> $target/etc/ld.so.conf, $target/lib, et cetera.  This is really great
> for people using, for instance, gdbserver to debug a remote GNU/Linux
> installation.  I bet the QNX people could use this, too.
> 
> Free bonus: as long as the sysroot is actually within $exec_prefix
> (otherwise the relocation functions don't work right), it will move
> along with the binary.  You can pick up the whole tree, drop it
> somewhere else, and keep using it; no rebuild, no reconfigure.
> 
> Here's a patch to do the same thing in GDB.  Right now all it sets is
> solib-absolute-prefix; that's because I can't think of anything else it
> should affect, but if you have any ideas speak right up.
> 
> It also documents solib-absolute-prefix and solib-search-path, which
> have been conspicuously missing from the manual for some time.
> 
> Thoughts?  I'll look to apply this in a couple of days if no one
> objects to the way I implemented it.

Thanks to Kevin and Elena for their feedback.  Here's what I committed;
I was also missing a ChangeLog entry for regenerating configure.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

2003-01-13  Daniel Jacobowitz  <drow@mvista.com>

	* Makefile.in (TARGET_SYSTEM_ROOT, TARGET_SYSTEM_ROOT_DEFINE): New
	variables.
	(main.o): Custom rule which uses $(TARGET_SYSTEM_ROOT_DEFINE).
	* configure.in: Add --with-sysroot.
	* configure: Regenerated.
	* main.c (gdb_sysroot): New variable.
	(captured_main): Initialize gdb_sysroot.
	* defs.h (gdb_sysroot): New extern declaration.
	* solib.c (_initialize_solib): Initialize solib_absolute_prefix.

2003-01-13  Daniel Jacobowitz  <drow@mvista.com>

	* gdb.texinfo (Files): Document solib-absolute-prefix and
	solib-search-path.

Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.311
diff -u -p -r1.311 Makefile.in
--- Makefile.in	9 Jan 2003 18:03:35 -0000	1.311
+++ Makefile.in	13 Jan 2003 17:29:57 -0000
@@ -136,6 +136,10 @@ INTL_CFLAGS = -I$(INTL_DIR) -I$(INTL_SRC
 # Where is the ICONV library?  This can be empty if libc has iconv.
 LIBICONV = @LIBICONV@
 
+# Did the user give us a --with-sysroot option?
+TARGET_SYSTEM_ROOT = @TARGET_SYSTEM_ROOT@
+TARGET_SYSTEM_ROOT_DEFINE = @TARGET_SYSTEM_ROOT_DEFINE@
+
 #
 # CLI sub directory definitons
 #
@@ -1402,6 +1406,11 @@ hpux-thread.o: $(srcdir)/hpux-thread.c
 	$(CC) -c $(INTERNAL_CFLAGS) -I$(srcdir)/osf-share \
 		-I$(srcdir)/osf-share/HP800 -I/usr/include/dce \
 		$(srcdir)/hpux-thread.c
+
+# main.o needs an explicit build rule to get TARGET_SYSTEM_ROOT and BINDIR.
+main.o: main.c
+	$(CC) -c $(INTERNAL_CFLAGS) $(TARGET_SYSTEM_ROOT_DEFINE) \
+		-DBINDIR=\"$(bindir)\" $(srcdir)/main.c
 
 # FIXME: Procfs.o gets -Wformat errors because things like pid_t don't
 # match output format strings.
Index: configure.in
===================================================================
RCS file: /cvs/src/src/gdb/configure.in,v
retrieving revision 1.116
diff -u -p -r1.116 configure.in
--- configure.in	4 Jan 2003 23:47:12 -0000	1.116
+++ configure.in	13 Jan 2003 17:29:59 -0000
@@ -851,6 +851,38 @@ fi
 
 dnl Handle optional features that can be enabled.
 
+AC_ARG_WITH(sysroot,
+[  --with-sysroot[=DIR] Search for usr/lib et al within DIR.],
+[
+ case ${with_sysroot} in
+ yes) AC_ERROR(with-sysroot must specify path) ;;
+ *) TARGET_SYSTEM_ROOT=$with_sysroot ;;
+ esac
+
+ TARGET_SYSTEM_ROOT_DEFINE='-DTARGET_SYSTEM_ROOT=\"$(TARGET_SYSTEM_ROOT)\"'
+
+ if test "x$exec_prefix" = xNONE; then
+  if test "x$prefix" = xNONE; then
+   test_prefix=/usr/local
+  else
+   test_prefix=$prefix
+  fi
+ else
+  test_prefix=$exec_prefix
+ fi
+ case ${TARGET_SYSTEM_ROOT} in
+ ${test_prefix}*)
+   t="$TARGET_SYSTEM_ROOT_DEFINE -DTARGET_SYSTEM_ROOT_RELOCATABLE"
+   TARGET_SYSTEM_ROOT_DEFINE="$t"
+   ;;
+ esac
+], [
+ TARGET_SYSTEM_ROOT=
+ TARGET_SYSTEM_ROOT_DEFINE='-DTARGET_SYSTEM_ROOT=\"\"'
+])
+AC_SUBST(TARGET_SYSTEM_ROOT)
+AC_SUBST(TARGET_SYSTEM_ROOT_DEFINE)
+
 # NOTE: Don't add -Wall or -Wunused, they both include
 # -Wunused-parameter which reports bogus warnings.
 # NOTE: If you add to this list, remember to update
Index: defs.h
===================================================================
RCS file: /cvs/src/src/gdb/defs.h,v
retrieving revision 1.107
diff -u -p -r1.107 defs.h
--- defs.h	6 Jan 2003 18:49:08 -0000	1.107
+++ defs.h	13 Jan 2003 17:29:59 -0000
@@ -1,7 +1,7 @@
 /* *INDENT-OFF* */ /* ATTR_FORMAT confuses indent, avoid running it for now */
 /* Basic, host-specific, and target-specific definitions for GDB.
    Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
-   1997, 1998, 1999, 2000, 2001, 2002
+   1997, 1998, 1999, 2000, 2001, 2002, 2003
    Free Software Foundation, Inc.
 
    This file is part of GDB.
@@ -168,6 +168,9 @@ extern int xdb_commands;
 
 /* enable dbx commands if set */
 extern int dbx_commands;
+
+/* System root path, used to find libraries etc.  */
+extern char *gdb_sysroot;
 
 extern int quit_flag;
 extern int immediate_quit;
Index: main.c
===================================================================
RCS file: /cvs/src/src/gdb/main.c,v
retrieving revision 1.20
diff -u -p -r1.20 main.c
--- main.c	26 Sep 2002 17:46:04 -0000	1.20
+++ main.c	13 Jan 2003 17:29:59 -0000
@@ -1,6 +1,6 @@
 /* Top level stuff for GDB, the GNU debugger.
    Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
-   1996, 1997, 1998, 1999, 2000, 2001, 2002
+   1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
    Free Software Foundation, Inc.
 
    This file is part of GDB.
@@ -65,6 +65,9 @@ int xdb_commands = 0;
 /* Whether dbx commands will be handled */
 int dbx_commands = 0;
 
+/* System root path, used to find libraries etc.  */
+char *gdb_sysroot = 0;
+
 struct ui_file *gdb_stdout;
 struct ui_file *gdb_stderr;
 struct ui_file *gdb_stdlog;
@@ -200,6 +203,34 @@ captured_main (void *data)
 
   /* initialize error() */
   error_init ();
+
+  /* Set the sysroot path.  */
+#ifdef TARGET_SYSTEM_ROOT_RELOCATABLE
+  gdb_sysroot = make_relative_prefix (argv[0], BINDIR, TARGET_SYSTEM_ROOT);
+  if (gdb_sysroot)
+    {
+      struct stat s;
+      int res = 0;
+
+      if (stat (gdb_sysroot, &s) == 0)
+	if (S_ISDIR (s.st_mode))
+	  res = 1;
+
+      if (res == 0)
+	{
+	  free (gdb_sysroot);
+	  gdb_sysroot = TARGET_SYSTEM_ROOT;
+	}
+    }
+  else
+    gdb_sysroot = TARGET_SYSTEM_ROOT;
+#else
+#if defined (TARGET_SYSTEM_ROOT)
+  gdb_sysroot = TARGET_SYSTEM_ROOT;
+#else
+  gdb_sysroot = "";
+#endif
+#endif
 
   /* Parse arguments and options.  */
   {
Index: solib.c
===================================================================
RCS file: /cvs/src/src/gdb/solib.c,v
retrieving revision 1.51
diff -u -p -r1.51 solib.c
--- solib.c	9 Dec 2002 00:59:26 -0000	1.51
+++ solib.c	13 Jan 2003 17:30:00 -0000
@@ -1,7 +1,7 @@
 /* Handle shared libraries for GDB, the GNU Debugger.
 
    Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -874,6 +874,10 @@ For other (relative) files, you can add 
 		   &setlist);
   add_show_from_set (c, &showlist);
   set_cmd_completer (c, filename_completer);
+
+  /* Set the default value of "solib-absolute-prefix" from the sysroot, if
+     one is set.  */
+  solib_absolute_prefix = xstrdup (gdb_sysroot);
 
   c = add_set_cmd ("solib-search-path", class_support, var_string,
 		   (char *) &solib_search_path,
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.136
diff -u -p -r1.136 gdb.texinfo
--- doc/gdb.texinfo	5 Jan 2003 04:34:39 -0000	1.136
+++ doc/gdb.texinfo	13 Jan 2003 17:30:05 -0000
@@ -9719,6 +9719,49 @@ Mb).
 Display the current autoloading size threshold, in megabytes.
 @end table
 
+Shared libraries are also supported in many cross or remote debugging
+configurations.  A copy of the target's libraries need to be present on the
+host system; they need to be the same as the target libraries, although the
+copies on the target can be stripped as long as the copies on the host are
+not.
+
+You need to tell @value{GDBN} where the target libraries are, so that it can
+load the correct copies---otherwise, it may try to load the host's libraries.
+@value{GDBN} has two variables to specify the search directories for target
+libraries.
+
+@table @code
+@kindex set solib-absolute-prefix
+@item set solib-absolute-prefix @var{path}
+If this variable is set, @var{path} will be used as a prefix for any
+absolute shared library paths; many runtime loaders store the absolute
+paths to the shared library in the target program's memory.  If you use
+@samp{solib-absolute-prefix} to find shared libraries, they need to be laid
+out in the same way that they are on the target, with e.g.@: a
+@file{/usr/lib} hierarchy under @var{path}.
+
+You can set the default value of @samp{solib-absolute-prefix} by using the
+configure-time @samp{--with-sysroot} option.
+
+@kindex show solib-absolute-prefix
+@item show solib-absolute-prefix
+Display the current shared library prefix.
+
+@kindex set solib-search-path
+@item set solib-search-path @var{path}
+If this variable is set, @var{path} is a colon-separated list of directories
+to search for shared libraries.  @samp{solib-search-path} is used after
+@samp{solib-absolute-prefix} fails to locate the library, or if the path to
+the library is relative instead of absolute.  If you want to use
+@samp{solib-search-path} instead of @samp{solib-absolute-prefix}, be sure to
+set @samp{solib-absolute-prefix} to a nonexistant directory to prevent
+@value{GDBN} from finding your host's libraries.
+
+@kindex show solib-search-path
+@item show solib-search-path
+Display the current shared library search path.
+@end table
+
 @node Symbol Errors
 @section Errors reading symbol files