Re: [patch] Don't set DT_HP_DEBUG_PRIVATE in solib-pa64.c

John David Anglin
2008-08-06T23:10:03Z

> Otherwise, I think this is ok (but perhaps the message that suggests
> using chatr can be improved).

How does this look?

The best online documentation for the methods to privately map shared
library text is <http://docs.hp.com/en/B2355-60130/chatr_pa.1.html>.
This is for 11i v3 but the same features are available on all HP-UX 11
versions with a recent linker patch. On HP-UX 11.11, chatr +dbg
support was added in PHSS_32864. Using _HP_DLDOPTS, it is possible
to map privately all or specific libraries without modifying the
libraries or executable.

It is also possible to use "pxdb -s on" to privately map the text segments
of shared libraries. See <http://docs.hp.com/en/B2355-60130/ld_pa.1.html>.

Dave
--
J. David Anglin dave.anglin@nrc-cnrc.gc.ca
National Research Council of Canada (613) 990-0752 (FAX: 952-6602)

2008-08-06 John David Anglin <dave.anglin@nrc-cnrc.gc.ca>

* solib-pa64.c (pa64_solib_create_inferior_hook): Don't set
DT_HP_DEBUG_PRIVATE. Add warning if DT_HP_DEBUG_PRIVATE is not set.
Revise comment.
(pa64_current_sos): Remove map private warning warning.

Index: solib-pa64.c
===================================================================
RCS file: /cvs/src/src/gdb/solib-pa64.c,v
retrieving revision 1.12
diff -u -3 -p -r1.12 solib-pa64.c
--- solib-pa64.c 6 Aug 2008 20:17:21 -0000 1.12
+++ solib-pa64.c 6 Aug 2008 22:49:28 -0000
@@ -322,13 +322,12 @@ bfd_lookup_symbol (bfd *abfd, char *symn
to tell the dynamic linker that a private copy of the library is
needed (so GDB can set breakpoints in the library).

- We need to set two flag bits in this routine.
-
- DT_HP_DEBUG_PRIVATE to indicate that shared libraries should be
- mapped private.
-
- DT_HP_DEBUG_CALLBACK to indicate that we want the dynamic linker to
- call the breakpoint routine for significant events. */
+ We need to set DT_HP_DEBUG_CALLBACK to indicate that we want the
+ dynamic linker to call the breakpoint routine for significant events.
+ We used to set DT_HP_DEBUG_PRIVATE to indicate that shared libraries
+ should be mapped private. However, this flag can be set using
+ "chatr +dbg enable". Not setting DT_HP_DEBUG_PRIVATE allows debugging
+ with shared libraries mapped shareable. */

static void
pa64_solib_create_inferior_hook (void)
@@ -360,8 +359,15 @@ pa64_solib_create_inferior_hook (void)
if (! read_dynamic_info (shlib_info, &dld_cache))
error (_("Unable to read the .dynamic section."));

+ /* If the libraries were not mapped private, warn the user. */
+ if ((dld_cache.dld_flags & DT_HP_DEBUG_PRIVATE) == 0)
+ warning
+ (_("Private mapping of shared library text was not specified\n"
+ "by the executable; setting a breakpoint in a shared library which\n"
+ "is not privately mapped will not work. See the HP-UX 11i v3 chatr\n"
+ "manpage for methods to privately map shared library text.\n"));
+
/* Turn on the flags we care about. */
- dld_cache.dld_flags |= DT_HP_DEBUG_PRIVATE;
dld_cache.dld_flags |= DT_HP_DEBUG_CALLBACK;
status = target_write_memory (dld_cache.dld_flags_addr,
(char *) &dld_cache.dld_flags,
@@ -454,12 +460,6 @@ pa64_current_sos (void)
if (! read_dld_descriptor ())
return NULL;

- /* If the libraries were not mapped private, warn the user. */
- if ((dld_cache.dld_flags & DT_HP_DEBUG_PRIVATE) == 0)
- warning (_("The shared libraries were not privately mapped; setting a\n"
- "breakpoint in a shared library will not work until you rerun "
- "the program.\n"));
-
for (dll_index = -1; ; dll_index++)
{
struct load_module_desc dll_desc;